CN110905697A

CN110905697A - System and method for intelligent vehicle evaporative emission diagnostics

Info

Publication number: CN110905697A
Application number: CN201910876224.1A
Authority: CN
Inventors: 艾德·M·杜道尔
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2018-09-18
Filing date: 2019-09-17
Publication date: 2020-03-24
Also published as: DE102019125039A1

Abstract

The present disclosure provides a system and method for intelligent vehicle evaporative emission diagnostics. Methods and systems are provided for cleaning a fuel vapor storage canister positioned in an evaporative emission control system of a vehicle. In one example, a method comprises: sealing a fuel system of the vehicle for reducing the predicted change in altitude ahead; and after the vehicle reduces the change in altitude, unsealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to a fuel tank of the vehicle. In this way, blowdown emissions from the fuel vapor storage canister may be reduced and engine operation may be improved.

Description

System and method for intelligent vehicle evaporative emission diagnostics

Technical Field

The present description relates generally to methods and systems for controlling a passive purge event of a fuel vapor storage canister based on a driving route known in advance.

Background

Vehicle emissions control systems may be configured to store fuel vapors from tank refueling and daytime engine operation in a fuel vapor storage canister and then purge the stored vapors during subsequent engine operation. In particular, purging stored vapor during engine operation may include: a canister purge valve positioned in a purge line between the engines is commanded to open and a canister vent valve positioned in a vent line coupling the canister to atmosphere is commanded to open. In this way, engine intake manifold vacuum may be applied to the canister, whereby atmospheric air may be drawn across the canister, which desorbs stored fuel vapors from the canister and directs them to the engine for combustion.

However, certain vehicles may face challenges in efficiently purging adsorbed fuel vapor from the fuel vapor storage canister. As one example, hybrid electric vehicles and/or vehicles equipped with start/stop capabilities may encounter limited engine run times in which the canister is to be cleaned. Additional problems may be encountered with vehicles designed to reduce engine intake manifold vacuum, as engine intake manifold vacuum is a pumping impairment. For example, a vehicle having an engine equipped with dual independent variable cam timing (TiVCT) may operate at low engine intake manifold vacuum, which may reduce the chance of effective canister purging. In yet another example, a boosted engine may generally be operated under positive engine intake manifold vacuum conditions, thus reducing the opportunity for canister purging. While such supercharged engines may have specific hardware for facilitating purging during supercharging operations, such as check valves and injectors, such purging may not be effective because the vacuum generated in such engines equipped with injectors may be limited due to throttling. It is therefore desirable for such vehicles to utilize any opportunity to clean the canister to reduce the opportunity for drain emissions from the canister to the atmosphere that may occur if the canister is not cleaned often.

To this end, U.S. patent No. 9,739,248 teaches: during engine off conditions when ambient temperature is falling, the vacuum in the fuel tank may increase to a point such that the vacuum-based valve opens, drawing air through the fuel vapor canister, thereby purging the canister and transporting fuel vapor back to the tank. This canister purge is referred to as a passive purge, as opposed to an active purge that relies on engine intake manifold vacuum. However, the inventors herein have recognized several problems with this approach. First, depending on environmental conditions (e.g., temperature, precipitation, wind, etc.), a sufficient vacuum may not be generated to achieve passive cleaning of the canister. Second, this approach relies on specially designed valves (e.g., vacuum-based valves) that may not be desirable to include in all vehicle fuel systems and which may increase the costs associated with vehicle assembly. Third, such vacuum-based valves may only have one set point below which the pressure in the fuel system is reached, thus limiting the ability to exercise any level of control over the extent to which the canister can be passively purged. Fourth, this approach relies on the vehicle soaking with the engine off for a significant period of time. Such extended vehicle shutdown soak periods may be very rare as more and more vehicles participate in the automobile sharing model in which vehicles may be rented for a short period of time, and thus, the chances of canister passive purging may be too rare.

Disclosure of Invention

The inventors herein have recognized the above-mentioned problems, and have developed systems and methods for at least partially addressing these problems. In one example, a method comprises: sealing a fuel system of a vehicle and then reducing an altitude change, the altitude change being predicted before the vehicle reduces the altitude change; and after the vehicle reduces the change in altitude, unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister to a fuel tank of the vehicle. In this way, the loading state of the canister may be reduced during vehicle operation without relying on engine operation. In one example, the altitude change predicted in advance may include an altitude change occurring along a learned driving route, wherein the learned driving route is learned over time. In another example, the altitude change known in advance may be based on a driving route selected by a driver of the vehicle or selected by a passenger.

In some examples, the altitude change predicted in advance may result in a negative pressure being created in the fuel system relative to atmospheric pressure, the negative pressure being at least a predetermined negative pressure, e.g., -8InH 2O.

In yet another example, such a method may include: de-activating the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude under conditions in the fuel system reaching a predetermined passive purge threshold negative pressure during the reducing the change in altitude; and resealing the fuel system in response to a pressure in the fuel system during the reducing the altitude change being within a threshold of atmospheric pressure (e.g., no more than 5% from atmospheric pressure). In some examples, the predetermined passive purge threshold negative pressure may include-16 InH 2O. Further, de-sealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude, and re-sealing the fuel system in response to the fuel system being within the threshold of atmospheric pressure, may occur any number of times during the time the vehicle is reducing the change in altitude.

The above advantages and other advantages and features of the present description will be readily apparent from the following detailed description when taken alone or in connection with the accompanying drawings.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. This is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

FIG. 1 schematically illustrates an exemplary vehicle propulsion system.

FIG. 2 schematically illustrates an exemplary vehicle system having a fuel system and an evaporative emission system.

FIG. 3 illustrates a high level flow chart of an exemplary method for machine learning common driving routes.

Fig. 4A schematically illustrates an exemplary learned driving route with predicted/learned stops, hill sections, and final destination.

Fig. 4B exemplarily illustrates an exemplary lookup table storing information about the exemplary learned driving route depicted at fig. 4A.

FIG. 5 illustrates a high level flow chart of an exemplary method for scheduling a test for undesirable evaporative emissions based on predicted/learned altitude changes encountered in a learned driving course.

FIG. 6 illustrates a high level flow chart for scheduling tests for undesirable evaporative emissions based on predicted/learned altitude changes encountered in a learned driving course.

FIG. 7 illustrates an exemplary timeline for testing for undesirable evaporative emissions based on predicted/learned altitude changes according to the methods of FIGS. 5 and 6.

FIG. 8 depicts a high level flow chart of an exemplary method for scheduling an Engine Off Natural Vacuum (EONV) test in response to one or more predicted/learned stops indicating greater than a predetermined duration for a current driving route.

FIG. 9 depicts a high level flow chart of an exemplary method for conducting an EONV test.

FIG. 10 illustrates an exemplary timeline for EONV testing for undesirable evaporative emissions according to the methods of FIGS. 8 and 9.

FIG. 11 illustrates a high level flow chart of an exemplary method for conducting an active vacuum drawn evaporative emissions test in response to one or more predicted/learned stops indicating less than a predetermined duration for a current driving route.

FIG. 12 shows a high level flow chart for conducting an active vacuum suction evaporative emissions test.

FIG. 13 illustrates an exemplary timeline for performing an active vacuum drawn evaporative emissions test according to the method of FIGS. 11 and 12.

FIG. 14 depicts a high level flow chart for generating an optimized schedule for conducting an evaporative emissions test diagnostic routine based on a learned route of travel.

FIG. 15 illustrates a high level flow chart for adjusting the aggressiveness of a canister purge event as a function of the results of a test for undesired evaporative emissions performed in accordance with the method of FIG. 6.

FIG. 16 shows a high level flow chart for performing a canister purge event depending on whether the aggressiveness of the purge event is adjusted according to FIG. 15.

FIG. 17 shows a high level flow chart for scheduling passive washes for one or more specific points of a driving cycle given the course of the driving cycle.

FIG. 18 illustrates a high level flow chart for conducting a passive purge event scheduled in accordance with the method depicted at FIG. 17.

FIG. 19 depicts an exemplary timeline for a passive wash event according to the method of FIG. 18.

Detailed Description

The following description relates to systems and methods for testing vehicle fuel systems and evaporative emissions systems for undesirable evaporative emissions and/or for passively purging a fuel vapor storage canister. Testing for undesirable evaporative emissions may be conducted on a vehicle system (such as the vehicle system depicted in fig. 1) that is capable of being propelled via the engine, via an on-board energy storage device (such as a battery), or a combination of the engine and the on-board energy storage device. The test may indicate whether the vehicle fuel system and evaporative emissions system depicted at FIG. 2 are free of undesirable evaporative emissions. The test for determining whether the fuel system and the evaporative emissions system are free of undesirable evaporative emissions may be based on a learned driving program for normal vehicle driving, where the normal driving program may be learned according to the method depicted at FIG. 3. The learned common travel program may include information regarding elevation changes associated with the hill section and the duration of vehicle parking along the learned route shown in fig. 4A. Such information may be stored in one or more look-up tables stored at the vehicle controller, as shown in fig. 4B.

Based on the learned travel schedule, tests for undesirable evaporative emissions may be scheduled accordingly. For example, in response to one or more hill sections indicated for a particular travel program, a Barometric Pressure (BP) change evaporative emission test may be scheduled according to the method depicted at fig. 5. The method for performing the BP change evaporative emissions test is shown at fig. 6. An exemplary timeline for performing the BP change evaporative emissions test is shown at fig. 7. In some examples, in response to one or more stops being indicated along a particular learned route, where the one or more stops are greater than a predetermined threshold duration, an Engine Off Natural Vacuum (EONV) test may be scheduled according to the method depicted at FIG. 8. A method for conducting the EONV test is shown at fig. 9. An exemplary timeline for conducting an EONV test is shown at FIG. 10. In still other examples, in response to one or more stops being indicated along a particular learned route, wherein the one or more stops are less than a predetermined threshold duration, an active vacuum drawn evaporative emissions test may be scheduled according to the method of fig. 11. A method for conducting an active suction evaporative emissions test is shown at fig. 12. An exemplary timeline for conducting an active suction evaporative emissions test is shown at FIG. 13. In some examples, a particular route may include one or more stops, where the one or more stops may include a predicted/learned stop duration that is greater than a predetermined threshold duration, less than a predetermined threshold duration, or some combination. Further, the particular route may additionally include one or more hill sections in which BP variation evaporative emission testing may be scheduled. Accordingly, an optimized schedule for evaporative emissions testing for a particular learned route of travel may be performed according to the method illustrated in FIG. 14.

In some examples, the fuel vapor canister may be passively purged after the BP change evaporative emissions test. In the event that such testing also results in passive canister purging, the aggressiveness of any active purging that relies on engine manifold vacuum to purge the canister may be adjusted based on the results of the BP change evaporative emissions test. Thus, FIG. 15 depicts an exemplary method for adjusting the aggressiveness of active purging as a function of the results of the BP varying evaporative emissions test. FIG. 16 depicts an exemplary method for actively purging the fuel vapor storage canister based on whether aggressiveness of the purge operation is adjusted. While in some examples, the canister passive purge may be performed after the BP change evaporative emissions test, in other examples, such passive purge may be scheduled based on a learned or otherwise known travel schedule. A method for scheduling one or more passive wash operations for a particular driving cycle is therefore depicted at fig. 17. FIG. 18 depicts an exemplary method for performing one or more scheduled passive purge operations. An exemplary timeline for performing the scheduled passive purge operation is depicted at fig. 19.

FIG. 1 illustrates an exemplary vehicle propulsion system 100. The vehicle propulsion system 100 includes a fuel-fired engine 110 and a motor 120. By way of non-limiting example, the engine 110 includes an internal combustion engine and the motor 120 includes an electric motor. Motor 120 may be configured to utilize or consume a different energy source than engine 110. For example, engine 110 may consume a liquid fuel (e.g., gasoline) to produce an engine output, and motor 120 may consume electrical energy to produce a motor output. Accordingly, a vehicle having a propulsion system 100 may be referred to as a Hybrid Electric Vehicle (HEV).

The vehicle propulsion system 100 may utilize a variety of different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes may enable engine 110 to be maintained in an off state (i.e., set to a deactivated state) in which fuel combustion at the engine is stopped. For example, under selected operating conditions, motor 120 may propel the vehicle via drive wheels 130, as indicated by arrow 122, while engine 110 is deactivated.

During other conditions, engine 110 may be set to a deactivated state (as described above), while motor 120 may be operable to charge energy storage device 150. For example, the motor 120 may receive wheel torque from the drive wheels 130, as indicated by arrow 122, wherein the motor may convert kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150, as indicated by arrow 124. This operation may be referred to as regenerative vehicle braking. Thus, in some examples, the motor 120 may provide a generator function. However, in other examples, the generator 160 may alternatively receive wheel torque from the drive wheels 130, wherein the generator may convert kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150, as indicated by arrow 162.

During still other operating conditions, engine 110 may operate by combusting fuel received from fuel system 140, as indicated by arrow 142. For example, engine 110 may be operable to propel the vehicle via drive wheels 130, as indicated by arrow 112, while motor 120 is deactivated. During other operating conditions, both the engine 110 and the motor 120 are each operable to propel the vehicle via the drive wheels 130, as indicated by

arrows

112 and 122, respectively. Configurations in which both the engine and the motor can selectively propel the vehicle may be referred to as parallel-type vehicle propulsion systems. It should be noted that in some examples, motor 120 may propel the vehicle via a first set of drive wheels, and engine 110 may propel the vehicle via a second set of drive wheels.

In other examples, vehicle propulsion system 100 may be configured as a tandem type vehicle propulsion system, where the engine does not directly propel the drive wheels. Conversely, the engine 110 is operable to provide power to the motor 120, which motor 120 in turn may propel the vehicle via the drive wheels 130, as indicated by arrow 122. For example, during selected operating conditions, the engine 110 may drive the generator 160, as indicated by arrow 116, and the generator 160 may in turn supply electrical energy to one or more of the motor 120 (as indicated by arrow 114) or the energy storage device 150 (as indicated by arrow 162). As another example, the engine 110 may be operable to drive the motor 120, and the motor 120 may in turn provide a generator function to convert the engine output to electrical energy, where the electrical energy may be stored at the energy storage device 150 for later use by the motor.

Fuel system 140 may include one or more fuel storage tanks 144 for storing fuel on-board the vehicle. For example, fuel tank 144 may store one or more liquid fuels, including but not limited to gasoline, diesel, and alcohol fuels. In some examples, the fuel may be stored on-board the vehicle as a blend of two or more different fuels. For example, the fuel tank 144 may be configured to store a blend of gasoline and ethanol (e.g., E10, E85, etc.) or a blend of gasoline and methanol (e.g., M10, M85, etc.), where these fuels or fuel blends may be delivered to the engine 110, as indicated by arrow 142. Still other suitable fuels or fuel blends may be supplied to the engine 110 where the fuel or fuel blend may be combusted at the engine 110 to produce an engine output. The engine output may be used to propel the vehicle, as indicated by arrow 112, or to recharge energy storage device 150 via motor 120 or generator 160.

In some examples, the energy storage device 150 may be configured to store electrical energy that may be supplied to other electrical loads (other than motors) resident on the vehicle, including cabin heating and air conditioning systems, engine starting systems, headlights, cabin audio and video systems, and the like. As non-limiting examples, energy storage device 150 may include one or more batteries and/or capacitors.

The control system 190 may be in communication with one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. The control system 190 may receive sensory feedback information from one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. Additionally, the control system 190 may send control signals to one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160 in response to such sensory feedback. The control system 190 may receive an indication of a driver requested output from the vehicle propulsion system of the vehicle driver 102. For example, control system 190 may receive sensory feedback from a pedal position sensor 194 in communication with pedal 192. Pedal 192 may illustratively refer to a brake pedal and/or an accelerator pedal. Further, in some examples, the control system 190 may communicate with a remote engine start receiver 195 (or transceiver), the remote engine start receiver 195 receiving the wireless signal 106 from the key fob 104 with the remote start button 105. In other examples (not shown), a remote engine start may be initiated via a cellular telephone or smartphone-based system, where the user's cellular telephone sends data to a server and the server communicates with the vehicle to start the engine.

The energy storage device 150 may periodically receive electrical energy from a power source 180 residing outside of the vehicle (e.g., not part of the vehicle), as indicated by arrow 184. As a non-limiting example, the vehicle propulsion system 100 may be configured as a plug-in Hybrid Electric Vehicle (HEV), wherein electrical energy may be supplied from the power source 180 to the energy storage device 150 via the electrical energy transfer cable 182. During operation to recharge the energy storage device 150 from the power source 180, the electrical transmission cable 182 may electrically couple the energy storage device 150 and the power source 180. When the vehicle propulsion system is operating to propel the vehicle, the electrical transmission cable 182 may be disconnected between the power source 180 and the energy storage device 150. The control system 190 may identify and/or control an amount of electrical energy stored at the energy storage device, which may be referred to as a state of charge (SOC).

In other examples, the electrical transmission cable 182 may be omitted, wherein electrical energy may be wirelessly received at the energy storage device 150 from the power source 180. For example, the energy storage device 150 may receive electrical energy from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. Accordingly, it should be appreciated that any suitable method may be used to recharge energy storage device 150 from a power source that does not form part of the vehicle. In this manner, motor 120 may propel the vehicle by utilizing an energy source other than the fuel utilized by engine 110.

The fuel system 140 may periodically receive fuel from a fuel source residing outside the vehicle. By way of non-limiting example, vehicle propulsion system 100 may be refueled by receiving fuel via fuel dispensing device 170, as indicated by arrow 172. In some examples, fuel tank 144 may be configured to store fuel received from fuel dispensing device 170 until the fuel is supplied to engine 110 for combustion. In some examples, the control system 190 may receive an indication of the level of fuel stored at the fuel tank 144 via a fuel level sensor. The level of fuel stored at the fuel tank 144 (e.g., as identified by a fuel level sensor) may be communicated to the vehicle operator, for example, via a fuel gauge or an indication in the vehicle dashboard 196.

The vehicle propulsion system 100 may also include an ambient temperature/humidity sensor 198, as well as roll stability control sensors, such as one or more lateral and/or longitudinal and/or yaw rate sensors 199. The vehicle dashboard 196 may include one or more indicator lights, and/or a text-based display in which messages are displayed to the operator. The vehicle dashboard 196 may also include various input portions for receiving driver inputs, such as buttons, touch screens, voice inputs/identifications, and the like. For example, the vehicle dashboard 196 may include a refuel button 197, which refuel button 197 may be manually actuated or pressed by the vehicle operator to initiate refueling. For example, as described in more detail below, in response to a vehicle operator actuating the refuel button 197, a fuel tank in the vehicle may depressurize such that refuelling may be performed.

The control system 190 may be communicatively coupled to other vehicles or infrastructure using suitable communication techniques, as is known in the art. For example, the control system 190 may be coupled to other vehicles or infrastructure via a wireless network 131, which wireless network 131 may include Wi-Fi, bluetooth, a type of cellular service, wireless data transfer protocols, and the like. The control system 190 may broadcast (and receive) information regarding vehicle data, vehicle diagnostics, traffic conditions, vehicle location information, vehicle operating procedures, etc. via vehicle-to-vehicle (V2V), vehicle-to-infrastructure-to-vehicle (V2I 2V), and/or vehicle-to-infrastructure (V2I) technology. The communications and information exchanged between vehicles may be direct between vehicles or may be multi-hop. In some examples, longer range communications (e.g., WiMax) may be used in conjunction with V2V or V2I2V to extend coverage over miles. In still other examples, the vehicle control system 190 may be communicatively coupled to other vehicles or infrastructure via the wireless network 131 and the internet (e.g., the cloud), as is generally known in the art. In some examples, the control system may be coupled to other vehicles or infrastructure via wireless network 131 in order to retrieve information applicable to route learning, as will be discussed in detail below.

The vehicle system 100 may also include an in-vehicle navigation system 132 (e.g., a global positioning system) with which a vehicle driver may interact. The navigation system 132 may include one or more position sensors for assisting in estimating vehicle speed, vehicle altitude, vehicle orientation/position, and the like. This information may be used to infer engine operating parameters, such as local atmospheric pressure. As discussed above, the control system 190 may be further configured to receive information via the internet or other communication network. Information received from a Global Positioning System (GPS) may be cross-referenced with information available via the internet to determine local weather conditions, local vehicle regulations, and the like. In one example, information received from a GPS may be used in conjunction with a route learning method so that the vehicle control system 190 may learn a route that the vehicle typically travels. In some examples, other sensors (e.g., 133) such as lasers, radar, sonar, acoustic sensors, etc. may additionally or alternatively be used in conjunction with an on-board navigation system to perform route learning for routes typically traveled by vehicles.

Fig. 2 shows a schematic depiction of a vehicle system 206. It is understood that the vehicle system 206 may comprise the same vehicle system as the vehicle system 100 depicted in FIG. 1. The vehicle system 206 includes an engine system 208, the engine system 208 coupled to an emissions control system 251 and a fuel system 218. It is understood that the fuel system 218 may include the same fuel system as the fuel system 140 depicted in FIG. 1. Emission control system 251 includes a fuel vapor container or canister 222 that may be used to capture and store fuel vapor. In some examples, the vehicle system 206 may be a hybrid electric vehicle system. However, it is understood that the description herein may relate to a non-hybrid vehicle, such as a vehicle equipped with only an engine and no on-board energy storage device, without departing from the scope of the present disclosure.

The engine system 208 may include an engine 110 having a plurality of cylinders 230. The engine 110 includes an engine intake 223 and an engine exhaust 225. The engine intake 223 includes a throttle 262, the throttle 262 being in fluid communication with the engine intake manifold 244 via an intake passage 242. Further, engine intake 223 may include an air box and filter (not shown) positioned upstream of throttle 262. The engine exhaust system 225 includes an exhaust manifold 248, the exhaust manifold 248 opening into an exhaust passage 235 that directs exhaust gas to the atmosphere. The engine exhaust system 225 may include one or more exhaust catalysts 270 that may be installed in the exhaust passage in a close-coupled position. The one or more emission control devices may include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, and/or the like. It should be understood that other components (such as various valves and sensors) may be included in the engine. For example, barometric pressure sensor 213 may be included in an engine intake. In one example, barometric pressure sensor 213 may be a Manifold Air Pressure (MAP) sensor and may be coupled to the engine intake downstream of throttle 262. Barometric pressure sensor 213 may rely on a partially open throttle or wide-open throttle condition, such as when the opening amount of throttle 262 is greater than a threshold, in order to accurately determine BP.

The fuel system 218 may include a fuel tank 220, the fuel tank 220 coupled to a fuel pumping system 221. It is understood that the fuel tank 220 may comprise the same fuel tank as the fuel tank 144 depicted above at fig. 1. Fuel pump system 221 may include one or more pumps for pressurizing fuel delivered to injectors of engine 110, such as the exemplary injector 266 shown. Although only a single injector 266 is shown, additional injectors may be provided for each cylinder. It should be appreciated that the fuel system 218 may be a returnless fuel system, or various other types of fuel systems. The fuel tank 220 may hold a variety of fuel blends, including fuels having a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, and the like, as well as combinations thereof. A fuel level sensor 234 located in the fuel tank 220 may provide an indication of the fuel level ("fuel level input") to the controller 212. As depicted, the fuel level sensor 234 may include a float connected to a variable resistor. Alternatively, other types of fuel level sensors may be used.

The vapors generated in the fuel system 218 may be directed to an evaporative emissions control system 251 including a fuel vapor canister 222 via a vapor recovery line 231 before being purged to the engine intake 223. The vapor recovery line 231 may be coupled to the fuel tank 220 via one or more conduits and may include one or more valves for isolating the fuel tank during certain conditions. For example, vapor recovery line 231 may be coupled to fuel tank 220 via one or more of conduits 271, 273, and 275, or a combination thereof.

Further, in some examples, one or more tank vent valves may be positioned in conduits 271, 273, or 275. Among other functions, the fuel tank vent valve may allow the fuel vapor canister of the emission control system to be maintained at a low pressure or vacuum without increasing the rate of evaporation of fuel from the tank (which would otherwise occur if the fuel tank pressure were reduced). For example, the conduit 271 may include a Grade Vent Valve (GVV) 287, the conduit 273 may include a Fill Limit Vent Valve (FLVV) 285, and the conduit 275 may include a Grade Vent Valve (GVV) 283. Additionally, in some examples, the recovery line 231 may be coupled to the fuel fill system 219. In some examples, the fueling system may include a fuel tank cap 205 for sealing the fueling system from the atmosphere. Refueling system 219 is coupled to fuel tank 220 via a fuel filler tube or neck 211.

Additionally, the refuel system 219 may include a refuel lock 245. In some examples, the fuel refill lock 245 may be a fuel tank cap locking mechanism. The fuel cap locking mechanism may be configured to automatically lock the fuel cap in the closed position such that the fuel cap cannot be opened. For example, the fuel tank cap 205 may remain locked via the fuel refill lock 245 when the pressure or vacuum in the fuel tank is greater than a threshold. In response to a refueling request, such as a request initiated by a vehicle driver, the fuel tank may be depressurized and the fuel tank cap unlocked after the pressure or vacuum in the fuel tank drops below a threshold. The fuel cap locking mechanism may be a latch or clutch that when engaged prevents removal of the fuel cap. The latch or clutch may be electrically latched, such as by a solenoid; or may be mechanically locked, for example by a pressure diaphragm.

In some examples, refuel lock 245 may be a filler pipe valve located at the mouth of fuel fill pipe 211. In such examples, the fuel refill lock 245 may not prevent the fuel cap 205 from being removed. Conversely, refuel lock 245 may prevent insertion of a refueling pump into fuel filler tube 211. The fill pipe valve may be electrically locked, such as by a solenoid; or mechanically locked, for example by a pressure diaphragm.

In some examples, refuel lock 245 may be a refuel door lock, such as a latch or clutch, that locks a refuel door located in a body panel of the vehicle. The refuel door lock may be electrically locked, such as by a solenoid; or mechanically locked, for example by a pressure diaphragm.

In examples where an electric mechanism is used to lock the refuel lock 245, the refuel lock 245 may be unlocked by a command from the controller 212, such as when the fuel tank pressure drops below a pressure threshold. In examples where a mechanical mechanism is used to lock the refuel lock 245, the refuel lock 245 is unlocked via a pressure gradient, such as when the fuel tank pressure drops to atmospheric pressure.

Emission control system 251 may include one or more emission control devices, such as one or more fuel vapor canisters 222 filled with a suitable adsorbent 286b, configured to temporarily trap fuel vapors (including vaporized hydrocarbons) and "run-away" (i.e., fuel vaporized during vehicle operation) during fuel tank refill operations. In one example, the sorbent 286b used is activated carbon. Emission control system 251 may also include a canister vent path or vent line 227, which canister vent path or vent line 227 may direct gas from canister 222 to the atmosphere when storing or trapping fuel vapor from fuel system 218.

The canister 222 may include a buffer zone 222a (or buffer zone), each of which includes an adsorbent. As shown, the volume of the buffer region 222a can be less than the volume of the canister 222 (e.g., a fraction of the volume of the canister 222). The sorbent 286a in the buffer zone 222a can be the same as or different from the sorbent in the canister (e.g., both can include carbon). The buffer zone 222a may be positioned within the canister 222 such that during loading of the canister, fuel tank vapors are first adsorbed within the buffer zone and then when the buffer zone is saturated, additional fuel tank vapors are adsorbed within the canister. In contrast, during canister purging, fuel vapor is first desorbed from the canister (e.g., to a threshold amount) and then desorbed from the buffer zone. In other words, the loading and unloading of the buffer zone is not coincident with the loading and unloading of the canister. Thus, the canister buffer zone functions to mitigate any fuel vapor spike flowing from the fuel tank to the canister, thereby reducing the likelihood of any fuel vapor spike entering the engine. One or more temperature sensors 232 may be coupled to and/or within canister 222. When the adsorbent in the canister adsorbs the fuel vapor, heat (adsorption heat) is generated. Likewise, heat is consumed when the adsorbent in the canister desorbs fuel vapor. In this manner, adsorption and desorption of fuel vapor by the canister may be monitored and estimated based on temperature changes within the canister.

Vent line 227 may also allow fresh air to be drawn into canister 222 when stored fuel vapor is purged from fuel system 218 to engine intake 223 via purge line 228 and purge valve 261. For example, purge valve 261 may be normally closed, but may be opened during certain conditions such that vacuum from engine intake manifold 244 is provided to the fuel vapor canister for purging. In some examples, the vent line 227 may include an air filter 259 disposed therein upstream of the canister 222.

In some examples, the flow of air and vapor between canister 222 and the atmosphere may be regulated by a canister vent valve 297 coupled within vent line 227. When canister vent valve 297 is included, canister vent valve 297 may be a normally open valve, such that fuel tank isolation valve 252 (FTIV) may control venting of fuel tank 220 to atmosphere. The FTIV 252 may be positioned between the fuel tank and the fuel vapor canister 222 within the conduit 278. The FTIV 252 may be a normally closed valve that, when open, allows fuel vapor to vent from the fuel tank 220 to the fuel vapor canister 222. The fuel vapor may then be vented to the atmosphere or purged to the engine intake system 223 via canister purge valve 261. As will be discussed in detail below, in some examples, an FTIV may not be included, while in other examples, an FTIV may be included. Accordingly, the use of FTIV will be discussed in relation to the methods described below where relevant.

The fuel system 218 may be operated in multiple modes by the controller 212 by selectively adjusting various valves and solenoids. It is understood that the control system 214 may comprise the same control system as the control system 190 depicted at FIG. 1 above. For example, the fuel system may be operated in a fuel vapor storage mode (e.g., during a fuel tank refueling operation and in the event the engine is not combusting air and fuel), wherein the controller 212 may open the isolation valve 252 (when included) while closing the Canister Purge Valve (CPV) 261 to direct the refueling vapors into the canister 222 while preventing the fuel vapors from being directed into the intake manifold.

As another example, the fuel system may be operated in a refueling mode (e.g., when a vehicle driver requests fuel tank refueling), wherein the controller 212 may open the isolation valve 252 (when included) while maintaining the canister purge valve 261 closed to depressurize the fuel tank before allowing fuel to be allowed to be added to the fuel tank. In this way, isolation valve 252 (when included) may remain open during refueling operations to allow refueling vapors to be stored in the canister. After the refueling is complete, the isolation valve may be closed.

As yet another example, the fuel system may be operated in a canister purge mode (e.g., after the emission control device light-off temperature has been reached and where the engine is combusting air and fuel), where the controller 212 may open the canister purge valve 261 while closing the isolation valve 252 (when included). Herein, vacuum generated by the intake manifold of the engine in operation may be used to draw fresh air through the air duct 227 and through the fuel vapor canister 222 to purge stored fuel vapor into the intake manifold 244. In this mode, fuel vapor purged from the canister is combusted in the engine. Purging may continue until the amount of fuel vapor stored in the canister is below a threshold.

The controller 212 may form part of a control system 214. In some examples, control system 214 may be the same as control system 190 shown in fig. 1. Control system 214 is shown receiving information from a plurality of sensors 216 (various examples of which are described herein) and sending control signals to a plurality of actuators 281 (various examples of which are described herein). As one example, the sensors 216 may include: an exhaust gas sensor 237 located upstream of the emission control device 270; a temperature sensor 233; a pressure sensor 291; a pressure sensor 282; and a canister temperature sensor 232. Other sensors (such as pressure, temperature, air-fuel ratio, and composition sensors) may be coupled to various locations in the vehicle system 206. As another example, the actuators may include a throttle 262, a fuel tank isolation valve 252, a canister purge valve 261, and a canister vent valve 297. The control system 214 may include a controller 212. The controller may receive input data from various sensors, process the input data, and trigger various actuators in response to the processed input data based on instructions or code programmed therein corresponding to one or more programs. Example control routines are described herein with respect to fig. 3, 5-6, 8-9, 11-12, and 14.

In some examples, the controller may be placed in a reduced power mode or sleep mode, where the controller maintains only basic functionality and operates at lower battery consumption than in a corresponding awake mode. For example, the controller may be placed in a sleep mode after a vehicle shutdown event in order to perform a diagnostic routine for a duration of time after the vehicle shutdown event. The controller may have a wake-up input that allows the controller to return to a wake-up mode based on input received from the one or more sensors. For example, opening of the vehicle door may trigger a return to the wake mode. In other examples, particularly with respect to the methods depicted in fig. 5-6, 8-9, 11-12, and 14, the controller may need to be awake in order to perform such methods. In such an example, the controller may remain awake for a duration (referred to as a period of time during which the controller remains awake to perform the long-term shutdown function) such that the controller may be awake to perform the evaporative emissions test diagnostic routine. In another example, the wake-up capability may enable the circuitry to wake-up the controller while refueling is occurring.

Controller 212 may intermittently perform an undesirable evaporative emissions detection procedure on fuel system 218 and/or evaporative emissions system 251 to confirm that undesirable evaporative emissions are not present in the fuel system and/or evaporative emissions system. Accordingly, the evaporative emissions detection routine (engine off test) may be performed at engine off using the Engine Off Natural Vacuum (EONV) and/or vacuum supplemented from the vacuum pump due to changes in temperature and pressure at the fuel tank after engine off. Alternatively, the evaporative emissions detection procedure may be performed by operating a vacuum pump and/or using engine intake manifold vacuum while the engine is operating. In some configurations, a Canister Vent Valve (CVV) 297 may be coupled within vent line 227. The CVV 297 may function to regulate the flow of air and vapor between the canister 222 and the atmosphere. CVV can also be used for diagnostic procedures. When included, the CVV may be opened during fuel vapor storage operations (e.g., during fuel tank refueling and while the engine is not running) so that air stripped of fuel vapor after passing through the canister may be pushed out to the atmosphere. Likewise, during a purge operation (e.g., during canister regeneration and while the engine is running), the CVV may be opened to allow a fresh airflow to strip off fuel vapors stored in the canister. In some examples, CVV 297 may be a solenoid valve, wherein opening or closing of the valve occurs via actuation of a canister vent solenoid. In particular, the canister vent valve may be open, which closes upon actuation of the canister vent solenoid. In some examples, CVV 297 may be configured as a latchable solenoid valve. In other words, when the valve is placed in the closed configuration, it latches closed without requiring additional current or voltage. For example, the valve may be closed with a 100ms pulse and then opened with another 100ms pulse at a later point in time. In this way, the battery charge required to maintain CVV closure is reduced. In particular, the CVV may be closed when the vehicle is shut down, thereby maintaining battery charge while maintaining the fuel emission control system sealed from the atmosphere.

While the EONV test is discussed above, other tests for undesirable evaporative emissions may be conducted, such as a barometric pressure change evaporative emissions test, which may rely on changes in altitude that result in pressure increases or decreases in the sealed fuel system and evaporative emissions system (e.g., closed CPV and closed CVV). The pressure trapped in the fuel system and the evaporative emissions system may be monitored for either a bleed-up or a bleed-down (depending on whether the vehicle is at a reduced or increased altitude, respectively) to indicate the presence or absence of undesirable evaporative emissions. Another example may include an active suction evaporative emissions test, which may include transmitting engine intake manifold vacuum (e.g., via an open CPV and a closed CVV) over the fuel system and the evaporative emissions system until a vehicle shut-down event associated with a learned stop is indicated. In response to indicating a vehicle shut-down event, the fuel system and evaporative emissions system (e.g., closed CPV and closed CVV) may be sealed, and the pressure bleed-off rise monitored to indicate the presence or absence of undesirable evaporative emissions. Such exemplary methods will be discussed in more detail below with respect to fig. 5-6, 8-9, 11-12, and 14.

Turning now to FIG. 3, a high level exemplary method 300 for learning a common driving route being traveled by a vehicle is shown. More particularly, method 300 may be used to learn common driving routes, and may further be used to learn/predict parking and hill segments associated with particular driving routes. It is to be understood that "park" herein may refer to a vehicle shutdown event (e.g., a key shutdown event). The duration of the learned/predicted stop corresponding to a particular driving route may be stored in one or more look-up tables stored at the vehicle controller. Further, information related to learned/predicted hill segments for a particular learned/predicted driving route may similarly be stored in one or more look-up tables stored at the vehicle controller. Still further, a final destination corresponding to one or more particular learned/predicted driving routes may be determined and stored in one or more look-up tables stored at the vehicle controller. Such information may be used to schedule appropriate evaporative emissions test diagnostic procedures, as will be discussed in detail below.

The method 300 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 300 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 300 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below.

The method 300 begins at 305 and may include: indicating whether a key start event is indicated. The key-on event may include: the ignition key is utilized to start the vehicle in an engine start mode or an electric only operating mode. In other examples, the key-on event may include depressing an ignition button on, for example, an instrument panel. Other examples may include a key fob (or other remote device including a smartphone, tablet, etc.) starting the vehicle in an engine start mode or an electric-only operating mode. If a key start event is not indicated at 305, the method 300 may proceed to 310 and may include: current vehicle operating parameters are maintained. For example, at 310, method 300 may include: the CPV, CVV, engine, etc. are maintained in their current configuration and/or current operating mode. The method 300 may then end.

Returning to 305, in response to indicating a key start event, method 300 may proceed to 315 and may include: access vehicle location, driver information, day of the week (DOW), time of day (TOD), etc. The identity of the driver may be entered by the driver or inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, etc. The vehicle location may be accessed via an in-vehicle navigation system (e.g., via GPS) or otherwise, such as via wireless communication with the internet.

Proceeding to 320, the method 300 may include: vehicle route information is recorded during a driving cycle beginning with a key-on event. In some examples, the vehicle route information may be divided into one or more segments, where the one or more segments are bounded by a key-on event indicating a starting location and a key-off event indicating a final destination. However, it is understood that there may be one or more stops between a key-on event signaling the start of the route and a key-off event indicating arrival at the final destination. Such a shutdown event may be an opportunity to perform an evaporative emissions test diagnostic, depending on the duration of the shutdown, as will be discussed in further detail below.

At 320, the vehicle controller may continuously collect data from various sensor systems and external sources regarding the operation/condition of the vehicle, location, traffic information, local weather information, and the like. Data may be collected by, for example, GPS (e.g., 132), inertial sensors (e.g., 199), lasers, radar, sonar, acoustic sensors, etc. (e.g., 133). Other feedback signals may also be read from the vehicle, such as inputs from sensors specific to the vehicle. Exemplary sensors may include: a tire pressure sensor, an engine temperature sensor, a braking heat sensor, a brake pad state sensor, a tire tread sensor, a fuel sensor, an oil level and quality sensor, and an air quality sensor for detecting temperature, humidity, and the like. Still further, at 320, the vehicle controller may also retrieve various types of non-real-time data that may be stored at the controller or may be retrieved wirelessly, such as information from detailed maps.

Thus, data regarding a particular route or course of travel may be obtained and stored at the vehicle controller during the course of driving the vehicle along the particular vehicle driving route. Proceeding to 325, the method 300 may include: the data is processed to establish a predicted/learned driving route. For example, numerous travel routes and corresponding information may be obtained and stored at a vehicle controller such that a predicted/learned driving route may be implemented with high accuracy. In some examples, the vehicle may travel along a route that is not traveled frequently (e.g., not "frequently"). It will therefore be appreciated that route information which is not significantly relevant to a normally traveled route may be periodically forgotten or removed from the vehicle controller in order to prevent an excessive amount of data relating to the vehicle travel program from accumulating.

In some examples, data collected from a vehicle travel program (including GPS data) may be applied to algorithms that are fed into one or more machine learning algorithms to determine common vehicle travel routes. Such examples are intended to be illustrative, and not limiting. For example, any common vehicle route learning method may be utilized via the vehicle controller to establish a learned travel route without departing from the scope of the present disclosure.

Learning the driving route at 325 may include: a hill segment of the particular driving route for which the pressure change production may be greater than a predetermined pressure change production threshold of the sealed fuel system and evaporative emissions system is determined. Learning the driving route at 325 may further include: a stop between the starting destination and the final destination (inclusive) is determined. For example, learning the driving route at 325 may include: learned/predicted vehicle stops (e.g., vehicle shut-down events) that are typically less than a predetermined duration (e.g., less than 45 minutes), and may further include: the learning/prediction is typically greater than a predetermined duration of parking (e.g., greater than 45 minutes). As discussed above and in further detail below, such information may be used to schedule evaporative emissions test diagnostics.

Proceeding to 330, the method 300 may include: information relating to the learned driving route is stored into one or more look-up tables at the vehicle controller. Such information may include the segments of a particular vehicle route, as well as one or more predicted/learned pressure change outcomes of the sealed fuel system and evaporative emissions system corresponding to the height variations of each segment (e.g., hill). Further, such information stored in one or more look-up tables may include an indication of the segment in which the parking is indicated, and may also include an indication of the learned/predicted duration of each indicated parking. Further, the information stored in the one or more look-up tables may include an indication of whether an evaporative emission test protocol may be performed for each segment of a particular learned driving route, and may also include an indication of which type of evaporative emission test may be performed for each segment in which it is indicated that an evaporative emission test may be performed. Such a lookup table may be utilized during a particular vehicle driving procedure in order to schedule evaporative emissions test diagnostic procedures such that robust results may be obtained, and wherein scheduling evaporative emissions tests may result in reducing or eliminating premature suspension of the initiated evaporative emissions tests.

Turning now to fig. 4A, a schematic diagram of an exemplary driving route 400 is shown. More particularly, the driving route 400 may include a learned driving route, as discussed above with respect to fig. 3. Driving route 400 may be divided into a plurality of individual segments, such as

segments

401, 402, 403, 404, 405, 406, 407, 408, and 409. Segment 402 may include a segment of driving route 400 that corresponds to an altitude that may be determined to result in a vacuum generation of-8 InH2O or higher, for example, for a sealed fuel system and evaporative emissions system of a particular vehicle. Similarly, the segment 406 may include a segment of the driving route 400 that corresponds to an altitude drop that may be determined to result in a vacuum generation of-8 InH2O or higher, for example, for a sealed fuel system and evaporative emissions system of a particular vehicle. In some examples, the determination of a section of the driving route where the expected vacuum production (of the sealed evaporative emission system and the fuel system) or alternatively the expected pressure production (of the sealed evaporative emission system and the fuel system where altitude is rising) is greater than a predetermined threshold (e.g., -8InH2O or 8InH2O) may be indicated in response to the learned driving route. In other examples, the segment in which the expected vacuum or pressure production of the sealed evaporative emissions system and fuel system is greater than a predetermined threshold may be determined in response to the vehicle driver entering the programmed route into an on-board navigation system (GPS system). For example, a vehicle driver-entered route may be analyzed for hill sections that may result in vacuum or pressure generation greater than one or more predetermined thresholds for a sealed fuel system and evaporative emissions system.

Driving route 400 also includes two potential stops corresponding to first stop 410 and second stop 412. As discussed above, the first and

second stops

410, 412 may be predicted or determined based on learned routes from driver usage profiles.

Turning to FIG. 4B, illustrated that coexistence can be generatedAn example table 420 stored at a vehicle controller (e.g., 212). The exemplary table 420 may represent the driving route 400 depicted at FIG. 4A. In particular, the exemplary table 420 may include the

segment

401 and 409, where the

segment

401 and 409 may correspond to the

segment

401 and 409 depicted at FIG. 4A above. The predicted/learned pressure change generation for the sealed evaporative emissions system and fuel system for each segment may be stored at exemplary table 420. Only the driving route 400 in which the predicted/learned pressure change generation amount is larger than the predetermined pressure change generation amount threshold (e.g., the pressure change generation amount threshold)>-8InH2O or>8InH2O) may be the section in which atmospheric pressure (BP) variation evaporative emissions testing may be conducted. More particularly, segment 402 may include a segment of driving route 400 where a decrease in altitude may cause the sealed fuel system and evaporative emissions system to create a vacuum generation of-9 InH 2O. Accordingly, BP change evaporative emissions testing may be conducted during the segment 402, as indicated at table 420. Similarly, segment 406 may include a segment of driving route 400 where a decrease in altitude may cause the sealed fuel system and evaporative emissions system to create a vacuum generation of-11 InH 2O. Accordingly, BP change evaporative emissions testing may be conducted during the segment 406, as indicated at table 420. Detailed examples of BP change evaporative emission tests will be discussed below with respect to the methods shown in fig. 5-6. In some examples, predicting the amount of vacuum to be achieved by a sealed fuel system and evaporative emissions system based on changes in altitude may be based on fuel levels. For example, as fuel levels decrease, the amount of vacuum available may be less. Thus, in some examples, the achievable vacuum level may be based on a low fuel level (e.g., less than full)¹/₄)。

Further, the

zones

401, 403, 404, 405, 407, 408, and 409 may represent zones in which BP variation evaporative emissions testing may not be conducted because the predicted/learned vacuum/pressure generation levels of the sealed fuel system and evaporative emissions system are less than a predetermined pressure variation generation threshold (e.g., < -8InH2O or <8InH 2O). Thus, BP-change evaporative emissions tests may not be conducted on such segments (e.g.,

segments

401, 403, 404, 405, 407, 408, and 409) where the predicted/learned vacuum/pressure production is less than the predetermined pressure change production threshold.

The example table 420 may also include predicted/learned stops along the driving route 400. Thus, the first stop 410 in segment 403 may include stops predicted/learned to have a duration of less than 45 minutes. Because the first stop 410 may include a stop predicted/learned to have a duration of less than 45 minutes (e.g., a vehicle shut-down event), an Engine Off Natural Vacuum (EONV) test may not be performed at the first stop 410. More particularly, as discussed above and in further detail below, the EONV test may comprise an evaporative emissions test that may last for 45 minutes. Thus, if the stop includes a duration of less than 45 minutes, the EONV test may not be completed before the vehicle is driven again. An initiated but not completed EONV test may affect the EONV test completion rate, may increase canister loading, may result in undesirable use of the valve being commanded open/closed for testing, and in some examples, may result in premature shut down of a refueling dispenser at a refueling station, and the like. Thus, by predicting which stops are less than 45 minutes, the EONV test may be prevented from being performed for such stops.

For predicted/learned stops expected to be less than 45 minutes, different approaches may be utilized so that evaporative emissions test diagnostics may be conducted in an accelerated manner. In particular, active vacuum suction evaporative emissions testing may be performed. The active vacuum draw evaporative emissions test may include: the Canister Purge Valve (CPV) is commanded to open and the Canister Vent Valve (CVV) is commanded to close to evacuate the fuel system and evaporative emissions system prior to engine shutdown. In response to engine shutdown, the fuel system and the evaporative emissions system may be sealed from the atmosphere and engine intake and pressure bleed-off rise may be monitored. A pressure bleed-up less than a pressure bleed-up threshold or a pressure bleed-up rate less than a pressure bleed-up rate threshold may indicate that the fuel system and the evaporative emissions system are free of undesirable evaporative emissions. Such an example of an active suction evaporative emissions test will be discussed in further detail below with respect to the methods depicted at fig. 11-12.

Thus, because the stop 410 during the segment 403 is indicated as being predicted/learned to be less than 45 minutes in duration, the type of evaporative emissions test that may be scheduled for the stop 410 may include an active vacuum draw evaporative emissions test. Such information may be included in the example table 420 and may be stored at the controller.

The parking 412 indicated as occurring during the segment 408 may be predicted/learned to be greater than 45 minutes in duration. Because the stop is greater than 45 minutes, the EONV test may be performed, as indicated at table 420. Typical examples of the EONV test will be discussed in detail below with respect to the methods depicted at FIGS. 8-9. Briefly, as discussed above, the EONV test may comprise: the fuel system and the evaporative emissions system are sealed in response to an engine shut-off event, and a pressure increase is monitored. If the pressure increase does not reach the positive pressure threshold, the system may be unsealed and returned to atmospheric pressure (e.g., the pressure may be relieved), after which the system may be resealed and vacuum buildup may be monitored. In response to the vacuum in the fuel system and the evaporative emissions system not reaching a vacuum threshold within a time frame of the EONV test (e.g., 45 minutes), an undesirable evaporative emission may be indicated. Alternatively, if a positive pressure threshold or a vacuum threshold is reached during the EONV test, the fuel system and the evaporative emissions system may be indicated as being free of undesirable evaporative emissions. In some examples, the positive pressure threshold and the vacuum threshold may be adjusted according to fuel level, fuel reed vapor pressure, ambient temperature, weather conditions, and the like.

However, while the EONV test may be conducted at predicted/learned stops of greater than 45 minutes, there may be situations where it may be beneficial to conduct an active vacuum drawn evaporative emissions test. Such examples may include a case where conditions for conducting an EONV test are not indicated to be met. For example, and as will be discussed in more detail below, if heat rejection from the engine to the fuel system is not indicated to be greater than a heat rejection inference threshold, an active vacuum drawn evaporative emissions test may instead be conducted. Thus, for the stop 412, and for the predicted/learned final destination (where both stops are predicted/learned to have a duration greater than 45 minutes), an EONV test or an active vacuum drawn evaporative emissions test may be conducted, depending on whether, for example, conditions are met for conducting the EONV test. Other examples where the EONV test may not be conducted may include an indication of wind speeds above a wind speed threshold or other weather conditions that may make EONV less likely to provide a robust result.

Turning to FIG. 5, a high level flow chart of an exemplary method 500 for scheduling and conducting a Barometric Pressure (BP) varying evaporative emissions test is shown. More specifically, method 500 may be implemented in response to the start of a driving cycle. In other words, the method 500 may be performed in response to initiating a driving cycle. The beginning of the driving cycle may include, for example, a key-on event.

The method 500 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 500 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 500 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below.

Method 500 begins at 505 and may include: indicating whether a key start event is indicated. The key-on event may include: the ignition key is utilized to start the vehicle in an engine start mode or an electric only operating mode. In other examples, the key-on event may include: depressing an ignition button on, for example, an instrument panel. Other examples may include: the key fob starts the vehicle in an engine start mode or an electric-only operating mode. If a key start event is not indicated at 505, method 500 may proceed to 510 and may include: current vehicle operating parameters are maintained. For example, at 510, method 500 may include: the CPV, CVV, engine, etc. are maintained in their current configuration and/or current operating mode. The method 500 may then end.

Returning to 505, if a key start event is indicated, method 500 may proceed to 515. At 515, the method 500 may include: driving route information is accessed. For example, accessing driving route information at 515 may include: learned driving route information is retrieved from a vehicle controller. More particularly, the particular learned driving route may be indicated as being the same as the current driving route. In other words, the current driving route can be matched with the learned driving route with a high probability. The learned driving route may be matched to the current driving route based on a plurality of variables including vehicle location, time of day, date, day of the week, trajectory, and/or driver status. The identity of the driver may be entered by the driver or may be inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, and the like. In another example, the vehicle driver may enter one or more destinations into an in-vehicle navigation system (e.g., GPS) such that accessing driving route information at 515 may include: driving route information input by a driver of the vehicle is accessed. In some examples, accessing driving route information may include: a lookup table, such as lookup table 420 depicted above at fig. 4B, is accessed in response to a particular driving route being identified with a high probability as the current driving route.

Proceeding to 520, the method 500 may include: indicating whether any segment of the current driving cycle contains an altitude change in which the pressure change generating amount may be greater than a predetermined pressure change generating amount threshold for the sealed fuel system and the evaporative emissions system. As discussed above, the pressure change production threshold may include vacuum formation of-8 InH2O or greater or pressure buildup of 8InH2O or greater.

If at 520, no hill segment is identified in the predicted/learned current driving cycle for which the vacuum or pressure production is greater than the predetermined pressure change production of the sealed fuel system and evaporative emissions system, method 500 may proceed to 525. At 525, the method 500 may include: the current driving cycle is continued without venting the atmospheric pressure (BP) change evaporative emissions test. The method 500 may then end.

Alternatively, at 520, in response to the current driving cycle including an indication of one or more hill sections in which BP-change evaporative emission testing may be conducted, method 500 may proceed to 530. At step 530, the method 500 may include: the BP-change evaporative emission test is scheduled for one or more appropriate segments of the current driving cycle. In some examples, if more than one segment is indicated as including a hill segment for which BP-varying evaporative emission tests may be conducted, then the BP-varying evaporative emission test may be scheduled for one of the one or more segments. As one example, where more than one segment is indicated as including a hill segment for which BP-varying evaporative emission tests may be conducted, BP-varying evaporative emission tests may be scheduled for segments in which the predicted/learned BP variation is greatest. However, in other examples, the BP change evaporative emission test may be scheduled for a segment where the predicted/learned BP change is lowest (but still above a predetermined pressure change generation threshold). In other examples, the BP-change evaporative emission test may be scheduled for a segment in which the BP change rate is the fastest. In still further examples, more than one BP change evaporative emissions test may be scheduled for the current driving cycle in response to an indication of more than one segment in which the predicted/learned vacuum/pressure generation is indicated as being greater than a predetermined pressure/vacuum generation for the sealed fuel system and evaporative emissions system. In other examples, BP varying evaporative emission tests may be arranged for a section in which a flat (e.g., non-rising or non-falling altitude) continuum of predetermined length follows a hill section, such that test results may be robust and do not require complex factors, such as varying BP.

In response to scheduling one or more BP change evaporative emissions tests at 530, method 500 may proceed to 535. At 535, the method 500 may include: the BP change evaporative emissions test was performed at an appropriate point in the current driving cycle. This method for performing the BP change evaporative emissions test is depicted in detail at fig. 6. In response to performing the BP change evaporative emissions test, the method 500 may end.

Turning to FIG. 6, a high level flow chart of an exemplary method 600 for conducting a Barometric Pressure (BP) change evaporative emissions test is shown. More particularly, such testing may be scheduled for one or more segments of a driving cycle, as discussed above with respect to the method 500 depicted at fig. 5 above. Such testing may be performed via the method 600 discussed below in response to conditions being met for performing the BP change evaporative emissions test.

The method 600 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 600 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 600 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as will be discussed below.

The method 600 begins at 602, and may include: indicating whether the conditions for conducting the BP change evaporative emissions test are met. In one example, satisfying the condition may include: the scheduled BP varying evaporative emissions test position was reached. Such an indication may be provided via an in-vehicle navigation system (e.g., GPS). In other examples, if GPS is not available, satisfying the condition may include: the scheduled BP varying evaporative emissions test location is reached as indicated via a lookup table, wherein the lookup table includes learned information from the common route, as discussed above with respect to fig. 4A-4B. Additionally or alternatively, in some examples, a vehicle BP sensor (e.g., 213) may be utilized to indicate that conditions for conducting a BP change evaporative emission test are satisfied. As one example, a predetermined amount of pressure change may be communicated to a vehicle controller to provide an indication that the vehicle is experiencing a change in altitude. Such information may be combined with information from learned common routes so that it may be determined whether the conditions for conducting the BP change evaporative emission test are met. In some examples, satisfying the conditions for performing the BP change evaporative emissions test may include: an indication that the fuel vapor storage canister (e.g., 222) is not being purged.

If conditions for performing the BP varying evaporative emissions test are indicated at 602 as not being met, the method 600 may proceed to 604 and may include: current vehicle operating parameters are maintained. For example, the CPV, CVV, and FTIV (where included) may be maintained in their current operating states. Method 600 may then end.

Returning to 602, in response to indicating that the conditions for performing the BP change evaporative emissions test are satisfied, method 600 may proceed to 605. At 605, the method 600 may include: the CVV is closed to seal the fuel system and the evaporative emissions system. Although not explicitly shown, in examples where the vehicle system includes an FTIV (e.g., 252), the FTIV may first be commanded open to allow the pressure in the fuel system and evaporative emissions system to reach atmospheric pressure before the CVV is commanded closed. Further, while not explicitly shown, it is understood that CPV is additionally maintained (or commanded) closed at 605.

Proceeding to 610, method 600 may include: fuel system and evaporative emissions system pressures are monitored. The pressure in the fuel system and the evaporative emissions system may be monitored via a Fuel Tank Pressure Transducer (FTPT) (e.g., 291). In the case of sealing the fuel system and the evaporative emission system during the elevation or lowering of the hill section, a positive pressure with respect to the atmospheric pressure may be formed, or a vacuum (e.g., a negative pressure with respect to the atmospheric pressure) may be formed. More specifically, if the altitude of the vehicle is rising (BP is falling), a positive pressure may be created, and in response to the altitude of the vehicle falling (BP rising), a negative pressure may be created. Thus, proceeding to step 615, the method 600 may include: indicating whether the first target pressure is reached. The first target pressure may include a pressure that, if reached, may indicate that the fuel system and the evaporative emissions system do not contain significant undesirable evaporative emissions (e.g., 0.09 inches). More particularly, if the first target pressure is not reached during an uphill or downhill grade, it may indicate that the undesirable evaporative emissions are escaping from a source having a size of 0.09 inches or greater. However, if the first target pressure is reached during an uphill or downhill grade, it may indicate that the undesirable evaporative emissions are not escaping from a source having a size of 0.09 inches or more.

Accordingly, at 615, it may be indicated whether a first target pressure threshold is reached. If at 615, it is not indicated that the first target pressure is reached, method 600 may proceed to 620 and may include: indicating whether the end of the predicted/learned hill section has been reached. Such an indication may be determined via a BP sensor (if the vehicle is equipped), via GPS, via information from learned routes, etc. If at 620 it is indicated that the end of the hill section has not been reached, then method 620 may return to 610 and may include: fuel system and evaporative emissions system pressures continue to be monitored. Alternatively, if the end of the hill section has been reached as indicated at 620, method 600 may proceed to 625. At 625, method 600 may include: indicating severe undesirable evaporative emissions (e.g., 0.09 inches or greater). Such an indication may be stored, for example, at the controller. Further, a Malfunction Indicator Light (MIL) may be illuminated on the vehicle dashboard to indicate to the vehicle driver that service of the vehicle is required.

Proceeding to 630, the method 600 may include: mitigating action is taken in response to an indication of severe undesirable evaporative emissions. In one example, taking mitigating actions may include: the vehicle is operated in an electric mode of operation whenever possible so that the undesirable evaporative emissions may be reduced until the source of the undesirable evaporative emissions has been addressed. Method 600 may then end.

Returning to 615, in response to reaching the first target pressure, method 600 may proceed to 635. At 635, the method 600 may include: indicating the absence of significant undesirable evaporative emissions. Such an indication may be stored, for example, at a vehicle controller.

Proceeding to 640, method 600 may include: the fuel system and evaporative discharge pressure are maintained at the target pressure until the end of the hill section is reached or the elevation change is completed. Thus, at 645, the method 600 may include: the CVV is cycled such that the target pressure is maintained during the duration of the vehicle upslope or downslope. By duty cycling the CVV, for example, pressure in the fuel system and the evaporative emissions system may be prevented from building up to a pressure greater than the target pressure. More particularly, the method 600 may include: indicating whether the change in altitude is complete, and in response to the pressure in the sealed fuel system and the evaporative emissions system reaching a predetermined pressure change generation threshold (also referred to herein as a target pressure) before the change in altitude is complete, maintaining the pressure in the fuel system and the evaporative emissions system below the predetermined pressure change generation threshold until the change in altitude is complete is indicated.

Proceeding to 650, method 600 may include: indicating whether the end of the hill section has been reached or the elevation change has been completed. As discussed above, such an indication may be indicated via a BP sensor (if the vehicle is equipped), via GPS, via information from learned routes, and so forth. If the end of the hill section has not been reached, indicated at 650, method 600 may include: maintaining the pressures in the fuel system and the evaporative emissions system at predetermined target pressures may include duty cycling the CVV, as discussed above.

Alternatively, in response to an indication that the end of the hill section has been reached or that the elevation change has been completed, method 600 may proceed to 655 and may include: command or maintain CVV closed. Although not explicitly shown, it is understood that the CPV may be maintained closed at 655. Thus, the fuel system and the evaporative emissions system may be sealed from the atmosphere and engine intake. In the event that a target positive pressure or vacuum is reached (depending on vehicle altitude rise or vehicle altitude fall, respectively), and the fuel system and evaporative emissions system are sealed from the atmosphere and engine air intake, the pressure in the fuel system and evaporative emissions system may be monitored at 660 for a duration to indicate the presence or absence of undesirable evaporative emissions that are not severe (e.g., 0.04 inches or greater, but less than 0.09 inches).

Thus, proceeding to 665, method 600 may include: indicating whether the pressure variations in the fuel system and the evaporative emissions system are less than a predetermined threshold. In some examples, at 665, method 600 may include: indicating whether the rate of pressure change in the fuel system and the evaporative emissions system is less than a predetermined rate of pressure change threshold. The predetermined threshold or predetermined rate of pressure change threshold may include one or more thresholds that, if met or exceeded, may indicate the presence of less severe undesirable evaporative emissions. In some examples, it may be appreciated that the predetermined threshold and/or the predetermined rate of pressure change threshold may be adjusted based on ambient temperature and fuel level.

Method 600 may proceed to 670 in response to a pressure change or rate of pressure change in the fuel system and the evaporative emissions system reaching or exceeding a predetermined pressure threshold or predetermined rate of pressure change threshold. At 670, the method 600 may include: indicating that there is not severe undesirable evaporative emissions. Such an indication may be stored, for example, at the controller. Further, the MIL may be illuminated, for example, on a vehicle dashboard, thereby alerting a vehicle driver to a need to service the vehicle.

Proceeding to 675, method 600 may include: a de-encapsulated fuel system and an evaporative emissions system. For example, the de-encapsulated fuel system and the evaporative emissions system may include: the CVV is commanded to open so that the pressure in the fuel system and the evaporative emissions system may return to atmospheric pressure. Although not explicitly shown, for vehicles equipped with an FTIV, the FTIV may be commanded to close in response to an indication that the fuel system and evaporative emissions system have reached atmospheric pressure.

Proceeding to 680, method 600 may include: the state of the fuel system and the evaporative emissions system is updated. For example, in response to an indication of less severe desired evaporative emissions in the fuel system and the evaporative emissions system, the controller may update the vehicle operating state to include operating the vehicle in an electric mode more frequently to reduce the amount of the desired evaporative emissions that may be released to the atmosphere. In another example, the canister purge schedule may be updated so that canister purges may be performed more frequently in order to direct vapors that may otherwise potentially escape to the atmosphere to the engine intake for combustion. Method 600 may then end.

Returning to 665, if a pressure change or rate of pressure change in the fuel system and the evaporative emissions system is indicated to have not reached or exceeded a predetermined pressure threshold, method 600 may proceed to 685. At 685, the method 600 can include: indicating the absence of undesirable evaporative emissions in the fuel system and the evaporative emissions system. Such an indication may be stored, for example, at the controller. Proceeding to 675, method 600 may include: a de-encapsulated fuel system and an evaporative emissions system. As discussed above, the de-encapsulated fuel system and evaporative emissions system may include: the CVV is commanded to open to return the fuel system and the evaporative emissions system to atmospheric pressure. As discussed, for vehicles equipped with an FTIV, the FTIV may be commanded to close in response to an indication that the fuel system and evaporative emissions system have reached atmospheric pressure.

Proceeding to 680, method 600 may include: the state of the fuel system and the evaporative emissions system is updated. Since it is indicated that there are no undesirable evaporative emissions in the fuel system and/or the evaporative emissions system, updating the state of the fuel system and the evaporative emissions system at 680 may include: the current operating parameters are maintained. Method 600 may then end.

Turning now to fig. 7, an exemplary timeline 700 for conducting a Barometric Pressure (BP) change vapor emission test according to the methods described herein with respect to fig. 5-6 and applicable to the systems described herein with reference to fig. 1-2 is shown. The timeline 700 includes a curve 705 indicating a start or shut down state of a vehicle engine over time. The timeline 700 also includes: a curve 710 indicating whether the conditions for the BP variation evaporative emissions test are met over time; and a curve 715 indicating whether over time the end of the hill segment on which the vehicle is traveling has been reached (yes) or has not been reached (no). The timeline 700 also includes: a curve 720 indicating the open or closed state of the CVV (e.g., 297) over time; and a curve 725 indicating the open or closed status of the CPV (e.g., 261) over time. The timeline 700 also includes a curve 730 that indicates pressure in the vehicle fuel system and the evaporative emissions system over time. The pressure may be at atmospheric pressure (atm), either positive (+) or negative (-) with respect to atmospheric pressure. Line 731 represents a first target pressure threshold (also referred to herein as a predetermined pressure change generating amount threshold) that, if not reached, may indicate a severe undesirable evaporative emission. Line 732 represents a predetermined pressure threshold that, if reached, may indicate a less severe, undesirable evaporative emission. It will be appreciated that both the first target pressure threshold 731 and the predetermined pressure threshold 732 may be below atmospheric pressure (e.g., negative relative to atmospheric pressure) when the vehicle is lowering in altitude. Line 733 represents another first target pressure threshold (also referred to herein as a predetermined pressure change generating amount threshold) that, if not reached, may indicate a severe undesirable evaporative emission. Line 734 represents another predetermined pressure threshold that, if reached, may indicate a less severe undesirable evaporative emission. It is appreciated that when the height of the vehicle is increasing, both the first target pressure threshold 733 and the predetermined pressure threshold 734 may be above atmospheric pressure (e.g., positive relative to atmospheric pressure). The timeline 700 also includes a curve 735 indicating whether undesirable evaporative emissions are indicated in the fuel system and the evaporative emissions system over time.

At time t0, it can be appreciated that the vehicle is in operation, being propelled via electric power only, because the engine is off, as indicated by curve 705. However, as shown by curve 710, the conditions for performing the BP change evaporative emissions test are not indicated to be satisfied. The vehicle has not yet begun an uphill or downhill slope and, therefore, has not indicated that the end of the hill section has been reached, which is shown by curve 715. The CVV is open and the CPV is closed, these are shown by

curves

720 and 725, respectively. The fuel tank is at atmospheric pressure, which is shown by curve 730. In this exemplary timeline, it can be appreciated that the vehicle does not have an FTIV. Thus, with the CVV open, the fuel tank is at atmospheric pressure. However, where appropriate in this specification, the use of an FTIV for an FTIV-equipped vehicle will be discussed. Furthermore, because the BP change evaporative emissions test has not been conducted in the current driving cycle, no undesirable evaporative emissions are indicated, which is shown by curve 735.

At time t1, it is indicated that the conditions for conducting the BP varying evaporative emissions test are satisfied. As discussed above, meeting the conditions for the BP change evaporative emissions test may include: the scheduled BP varying evaporative emissions test position was reached. Such an indication may be provided via GPS or via a look-up table that includes learned information from common routes, as discussed above with respect to fig. 4A-4B. In some examples, a vehicle BP sensor (e.g., 213) may be utilized to indicate that conditions for conducting a BP change evaporative emission test are satisfied, as discussed above with respect to fig. 6.

The CVV is commanded to close in response to the conditions for performing the BP change evaporative emissions test being met. More particularly, a signal may be sent via the controller to an actuator of the CVV to actuate the CVV to close. In this exemplary illustration, it can be appreciated that at time t1, a decrease in vehicle altitude begins. Thus, with the CVV and CPV closed, as the vehicle lowers height, vacuum builds up in the fuel system and evaporative emissions system between times t1 and t2, which is indicated by curve 730. While this exemplary illustration depicts a vehicle without an FTIV, it is understood that in response to conditions being met for performing a BP varying evaporative emissions test, the FTIV may be commanded open to relieve pressure in the fuel system prior to sealing the fuel system and the evaporative emissions system via closing the CVV.

At time t2, vacuum builds to a first target threshold represented by line 731. The first target threshold may represent a threshold that, if reached, indicates that there are no significant undesirable evaporative emissions (illustrated by curve 735). However, although the target vacuum has been reached, the end of reaching the hill section has not been indicated. Thus, the CVV cycle is duty cycled between times t2 and t3 to maintain the vacuum in the fuel system and the evaporative emissions system at the target vacuum level represented by line 731.

At time t3, the end of the hill section is indicated. Such an indication may be provided via GPS (if the vehicle is equipped), via a look-up table based on learned driving routes, via a BP sensor, etc. In response to an indication that the end of the hill section has been reached, the fuel system and evaporative emission system may be sealed by closing the CVV and maintaining the CPV closed. Thus, between times t3 and t4, the pressure in the fuel system and the evaporative emissions system is monitored for a pressure bleed-off rise. In some examples, the time frame for monitoring the pressure relief rise may include a predetermined duration. Because the pressure in the fuel system and the evaporative emissions system remains below the predetermined threshold, shown by line 732, no less severe undesirable evaporative emissions are indicated, which is shown by curve 735. In some examples, rather than utilizing a predetermined pressure threshold, a predetermined rate of pressure change threshold may be utilized to monitor the rate of pressure change in the fuel system and the evaporative emissions system. In such an example, in response to the rate of pressure change in the fuel system and the evaporative emissions system being below a predetermined rate of pressure change threshold, no less severe undesirable evaporative emissions may be indicated.

In response to the indication at time t4 that there are no undesirable evaporative emissions, the CVV is commanded to open, thereby relieving pressure in the fuel system and the evaporative emissions system such that the pressure returns to atmospheric pressure. When the test is complete, it is no longer indicated that the conditions for conducting the BP change evaporative emissions test are satisfied.

After a period of time, the vehicle is operated again. For example, the vehicle may have been shut down and another driving route may then begin. At time t5, it is indicated that the conditions for conducting the BP varying evaporative emissions test are satisfied. In this example, at time t5, it can be appreciated that the vehicle is beginning to ascend a hill. In the event that the conditions for conducting the BP change evaporative emissions test are met, the CVV is commanded to close, and thus, the pressure in the fuel system and the evaporative emissions system builds up between times t5 and t6 as a result of the vehicle altitude increasing. As discussed above, for vehicles equipped with an FTIV, in response to the conditions for the BP change evaporative emissions test being met, the FTIV may be commanded to open to relieve pressure in the fuel system and the evaporative emissions system prior to commanding the CVV to close.

At time t6, another first target pressure, represented by line 733, is reached. However, the vehicle has not finished ascending a hill. Thus, between times t6 and t7, the CVV cycle is duty cycled to maintain the pressure in the fuel system and the evaporative emissions system at the target pressure. Furthermore, because another first target pressure is reached at time t6, severe undesirable evaporative emissions are not indicated, which is illustrated by curve 735.

At time t7, it is indicated that the end of the hill section has been reached. Thus, the fuel system and the evaporative emissions system are sealed from the atmosphere and the engine intake via commanding the CVV to close and maintaining the CPV closed. The pressure in the fuel system and the evaporative emissions system is then monitored for a pressure bleed down. In some examples, the monitored rate of pressure bleed down may be compared to a predetermined rate of pressure bleed down threshold. However, in this exemplary illustration, a predetermined pressure threshold is utilized as represented by line 734. For example, if the pressures in the fuel system and the evaporative emissions system meet or exceed a predetermined pressure threshold, then less severe undesirable evaporative emissions may be indicated.

At time t8, the pressure relief in the fuel system and the evaporative emissions system drops to a predetermined pressure threshold represented by line 734. Thus, at time t8, less severe undesirable evaporative emissions are indicated, which is represented by curve 735. In the event that less severe undesirable evaporative emissions are indicated at time t8, the conditions for conducting the BP varying evaporative emissions test are no longer indicated, as shown by curve 710. The CVV is commanded to open to relieve pressure in the fuel system and the evaporative emissions system. Thus, between times t8 and t9, the pressure in the fuel system and the evaporative emissions system is returned to atmospheric pressure. For vehicles equipped with an FTIV, the FTIV may be commanded to close in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure.

In some examples, although not explicitly shown herein, for vehicles having an FTIV, there may be opportunities to specifically diagnose the presence or absence of undesirable evaporative emissions in the fuel system or evaporative emissions system. For example, a BP change evaporative emissions test may be first conducted with the FTIV open, as discussed above. If an undesired evaporative emission is indicated, a subsequent BP varying evaporative emission test may be conducted with the FTIV closed to isolate the source of the undesired evaporative emission. For example, with the FTIV closed, the pressure in both the fuel system and the evaporative emissions system may be monitored separately. Thus, each system (e.g., fuel system and evaporative emissions system) may be diagnosed separately in the same manner as the coupled fuel system and evaporative emissions system. In this way, the source of the undesirable evaporative emissions may be more accurately indicated for vehicles having an FTIV.

Turning to FIG. 8, a high level flow chart of an exemplary method 800 for conducting an Engine Off Natural Vacuum (EONV) test is shown. More particularly, the EONV test may be scheduled only for those parking or destinations for which the vehicle is predicted/learned to be in a key-off (e.g., vehicle-off) state for greater than a predetermined duration (e.g., >45 minutes).

The method 800 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 800 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 800 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as will be discussed below.

Method 800 begins at 805 and may include: indicating whether a key start event is indicated. As discussed above, the key-on event may include: the ignition key is utilized to start the vehicle in an engine start mode or an electric only operating mode. In other examples, the key-on event may include: depressing an ignition button on, for example, an instrument panel. Other examples may include: the key fob starts the vehicle in an engine start mode or an electric-only operating mode. If a key start event is not indicated at 805, the method 800 may proceed to 810 and may include: current vehicle operating parameters are maintained. For example, at 510, method 500 may include: the CPV, CVV, engine, etc. are maintained in their current configuration and/or current operating mode. Method 800 may then end.

Returning to 805, if a key-on event is indicated, method 800 may proceed to 815. At 815, the method 800 may include: driving route information is accessed. For example, accessing driving route information at 815 may include: learned driving route information is retrieved from a vehicle controller. More particularly, the particular learned driving route may be indicated as being the same as the current driving route. In other words, the current driving route can be matched with the learned driving route with a high probability. The learned driving route may be matched to the current driving route based on a plurality of variables including vehicle location, time of day, date, day of the week, trajectory, and/or driver status. The identity of the driver may be entered by the driver or may be inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, and the like. In another example, the vehicle driver may enter one or more destinations into an in-vehicle navigation system (e.g., GPS), such that accessing driving route information at 815 may include: driving route information input by a driver of the vehicle is accessed. In some examples, accessing driving route information may include: a lookup table, such as lookup table 420 depicted above at fig. 4B, is accessed in response to a particular driving route being identified with a high probability as the current driving route.

Proceeding to 820, method 800 may include: indicating whether any predicted/learned stops are indicated for a particular driving route including the current driving cycle. More particularly, at 820, method 800 may include: indicating whether any predicted/learned stops are greater than a predetermined threshold duration, where the predetermined threshold duration may include a duration of 45 minutes or longer, for example. If at 820 it is indicated that there is a high likelihood of no predicted/learned stops in the current driving cycle comprising the predicted/learned driving route, method 800 may proceed to 825 and may include: the EONV test is scheduled for the final destination. In some examples, the final destination may include a home in which the vehicle is parked after being utilized during the day. In other examples, the final destination may include a work site or the like. In still other examples, the final destination may be programmed into an in-vehicle navigation system (such as GPS), for example. It will be appreciated that the final destination may include a destination where the duration of the predicted/learned vehicle stop will be greater than a predetermined threshold duration.

Alternatively, in response to one or more stops during the current driving cycle being predicted to be greater than 45 minutes in duration (e.g., greater than a predetermined threshold duration), an EONV test may be scheduled for one or more stops greater than the predetermined threshold duration. In some examples, only one EONV test may be scheduled during a driving cycle in which a stop is predicted/learned to be greater than a predetermined threshold duration more than once. However, in other examples, multiple EONV tests may be scheduled during a driving cycle in response to an indication that more than one stop is predicted/learned to be greater than a predetermined threshold duration. In some examples, where more than one stop is indicated as being greater than a predetermined threshold duration, an EONV test may be scheduled for stops where conditions for conducting the EONV test are most likely to be met. For example, because the EONV test is based on the amount of heat rejected from the engine during a driving cycle, the EONV test may be scheduled for a stop after which conditions for conducting the EONV test will most likely be met, such as aggressive driving for a period of time (where heat rejection to the engine is likely to be high).

Thus, in response to predicting/learning an indication that one or more stops in the current driving cycle are greater than a predetermined threshold duration, method 800 may proceed to 830 and may include: the EONV test is scheduled for one or more stops of greater than a predetermined duration.

Whether the EONV test is scheduled for the final destination as indicated at step 825 or scheduled for one or more stops predicted/learned to be greater than a predetermined duration as indicated at step 830, the method 800 may include: at 835 an EONV test is performed according to the method depicted at FIG. 9. Method 800 may then end.

Turning to FIG. 9, a high-level flow diagram of an exemplary method 900 for conducting an EONV test is shown. More particularly, the EONV test may be scheduled for one or more stops during the driving route, where the one or more stops are predicted to be greater than a predetermined threshold duration. Alternatively, in response to no stop being predicted/learned to be greater than a predetermined threshold duration during the driving route, an EONV test may be conducted at the final destination, as discussed above with respect to method 800 depicted at FIG. 8. In either case, however, the EONV test is performed in the same manner, and thus, the method for conducting the EONV test is depicted herein in accordance with method 900. In still other examples, an EONV test may be scheduled for a final destination even if one or more stops are predicted to be greater than a predetermined threshold duration.

In one example, diagnosing the fuel system and the evaporative emissions system based on the learned shutdown duration may include: sealing the fuel system and the evaporative emissions system in response to a vehicle shut-down event corresponding to a learned shutdown duration comprising a duration greater than a predetermined threshold duration; and indicating the absence of the undesirable evaporative emissions in response to reaching the predetermined positive pressure threshold. In a condition in which a positive pressure threshold is not indicated to be reached, the method may include: the pressure in the fuel system and the evaporative emissions system is released and the fuel system and the evaporative emissions system are then resealed. Subsequently, the method may comprise: in response to reaching the predetermined negative pressure threshold, an absence of undesirable evaporative emissions in the fuel system and the evaporative emissions system is indicated.

The method 900 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 900 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 900 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as will be discussed below.

Method 900 begins at 905 and may include: and evaluating the current working condition. The operating conditions may be estimated, measured, and/or inferred, and may include one or more vehicle conditions (such as vehicle speed, vehicle location, etc.), various engine conditions (such as engine state, engine load, engine speed, air/fuel (A/F) ratio, etc.), various fuel system conditions (such as fuel level, fuel type, fuel temperature, etc.), various evaporative emission system conditions (such as fuel vapor canister load, fuel tank pressure, etc.), and various environmental conditions (such as ambient temperature, humidity, atmospheric pressure, etc.).

Proceeding to 910, method 900 may include: indicating whether a condition for conducting an EONV test is indicated to be met. Satisfying the conditions for conducting the EONV test may include: a vehicle shutdown event, which may include an engine shutdown event and may be indicated by other events (such as a key shutdown event). The conditions for conducting the EONV test may further include: the parking of the vehicle concurrent with the key-off event is predicted/learned as an indication of greater than a predetermined threshold duration (e.g., greater than 45 minutes), as discussed above with respect to fig. 8. Satisfying the conditions for the EONV test at 910 may also include: a threshold length of engine run time prior to an engine shut-down event, a threshold amount of fuel in the fuel tank, and a threshold battery state of charge.

In some examples, satisfying the conditions for conducting the EONV test at 910 may include: an HRI greater than a Heat Rejection Inference (HRI) threshold. In one example, the HRI may be based on the amount of heat the engine has rejected during previous driving cycles, the timing of the amount of heat rejected, the length of time spent at different levels of driving aggressiveness, ambient conditions, and the like. The heat rejected by the engine may be inferred based on one or more of engine load, injected fuel summed over time, intake manifold air mass summed over time, mileage, etc. In some examples, the HRI threshold may be a function of ambient temperature and fuel level. For example, for a given ambient temperature, a fuel tank with a higher fill level may require a greater amount of engine run time in order to meet the HRI threshold. More specifically, for a given ambient temperature, the HRI threshold may decrease with decreasing fuel level, and for a given ambient temperature, the HRI threshold may increase with increasing fuel level.

If at 910, conditions for conducting the EONV test are not indicated to be met, the method 900 may proceed to 915 and may include: current vehicle operating parameters are maintained. For example, CPV, CVV, and FTIV (where included) may be maintained in their current configuration. Further, in response to not indicating that the conditions for the EONV test are met, the engine may remain in its current operating state. Method 900 may then end.

Returning to 910, in response to indicating that the conditions for conducting the EONV test are satisfied, method 900 may proceed to 920. At 920, method 900 may include: keeping the vehicle controller awake (e.g., maintaining power to the controller) and sealing the fuel system and evaporative emissions system. More specifically, the CVV may be commanded to close to seal the fuel system and the evaporative emissions system from the atmosphere. Further, the CPV may be maintained in (or commanded to) a closed configuration to seal the fuel system and the evaporative emissions system from the engine air intake. Still further, where an FTIV is included in the vehicle, the FTIV may be commanded open to couple the fuel system to the evaporative emission system.

Proceeding to 925, method 900 may include: fuel system and evaporative emissions system pressures are monitored for a duration of time. Fuel system and evaporative emissions system pressures may be monitored, for example, via a fuel tank pressure sensor (FTPT) (e.g., 291). Proceeding to 930, method 900 may include: indicating whether a positive pressure threshold has been reached. In response to the indication that the positive pressure threshold has been reached, method 900 may proceed to 935 and may include: indicating the absence of undesirable evaporative emissions in the fuel system and the evaporative emissions system. Such an indication may be stored, for example, at the controller.

In response to an indication of an absence of undesired evaporative emissions, method 900 may proceed to 940 and may include: a de-encapsulated fuel system and an evaporative emissions system. For example, at 940, method 900 may include commanding the CVV to open. In some examples where the vehicle includes an FTIV, the FTIV may be held open in response to commanding the CVV to open, and may be commanded closed in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure.

Proceeding to 945, method 900 may include: the vehicle operating parameters are updated. In the event that an EONV test is conducted and no undesirable evaporative emissions are indicated, updating 945 the vehicle operating parameters may include: current vehicle operating parameters are maintained. For example, a canister purge schedule may be maintained in its currently scheduled state. Additionally, engine operating parameters, etc. may be maintained.

Returning to 930, if a positive pressure threshold is not indicated, method 900 may proceed to 950. At 950, method 900 may include: indicating whether a pressure plateau has been reached. For example, the pressure plateau may include the pressure in the fuel system and the evaporative emissions system reaching a particular pressure that is below the positive pressure threshold and does not continue to rise further in the direction of the positive pressure threshold. In some examples, a pressure plateau may be indicated if the pressure in the fuel system and the evaporative emissions system reaches a predetermined level below the positive pressure threshold for a duration of time. If a pressure plateau is not indicated at 950, method 900 may return to 925 and may continue to monitor the pressure in the fuel system and the evaporative emissions system. Alternatively, at 950, if a pressure plateau is indicated, method 900 may proceed to 955.

At 955, the method 900 may include: command CVV to open, and may further include: allowing the pressure in the fuel system and the evaporative emissions system to stabilize. For example, allowing the fuel system and the evaporative emissions system to stabilize may include: allowing the pressure in the fuel system and evaporative emissions system to reach atmospheric pressure. In vehicles including an FTIV, the FTIV may be maintained open at 955.

In response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure, method 900 may proceed to 960, and may include: the CVV is closed to again seal the fuel system and the evaporative emissions system from the atmosphere and engine intake. Proceeding to 965, the method 900 may include: fuel system and evaporative emissions system pressures are monitored, similar to those discussed above. At 970, method 900 may comprise: indicating whether a vacuum threshold (e.g., a negative pressure threshold relative to atmospheric pressure) has been reached in the fuel system and the evaporative emissions system. In response to reaching the vacuum threshold at 970, method 900 may proceed to 935 and may include: indicating the absence of undesirable evaporative emissions. Proceeding to 940, method 900 may include: the fuel system and the evaporative emissions system are de-sealed so that the fuel system and evaporative emissions system pressures may return to atmospheric pressure. In examples where the vehicle includes an FTIV, the FTIV may be commanded to close in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure.

Proceeding to 945, method 900 may include: in response to an indication that the undesired evaporative emissions are not present, the vehicle operating parameters are updated. As discussed above, in the event that an EONV test is conducted and no undesirable evaporative emissions are indicated, updating 945 the vehicle operating parameters may include: current vehicle operating parameters are maintained. For example, a canister purge schedule may be maintained in its currently scheduled state. Engine operating parameters may be maintained, etc.

Returning to 970, in response to not indicating that the vacuum threshold is reached, method 900 may proceed to 975 and may include: indicating whether a predetermined duration for conducting the EONV test has expired. As discussed above, in some examples, such a predetermined duration may include 45 minutes. If at 975, it is not indicated that the predetermined duration for conducting the EONV test has been reached, then method 900 may return to 965 and may include: fuel system and evaporative emissions system pressures continue to be monitored.

Alternatively, at 975, in response to an indication that the EONV time limit has expired, and further in response to an indication that the vacuum threshold has not been reached, method 900 may proceed to 980, and may include: indicating the presence of undesirable evaporative emissions. In another example, method 900 may proceed to 980 in response to the pressures in the fuel system and the evaporative emissions system stabilizing (e.g., reaching a plateau) for a predetermined duration without reaching a vacuum threshold. At 980, an indication of the undesirable evaporative emissions may be stored, for example, at the controller. Further, at 980, method 900 may include: a Malfunction Indicator Light (MIL) is illuminated on the vehicle dashboard to alert the vehicle driver that service of the vehicle is required.

Proceeding to 940, method 900 may include: a de-encapsulated fuel system and an evaporative emissions system. As discussed above, the de-encapsulated fuel system and evaporative emissions system may include: the CVV is commanded to open to enable the pressure in the fuel system and the evaporative emissions system to return to atmospheric pressure. In vehicles including an FTIV, the FTIV may be commanded to close in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure.

Proceeding to 945, method 900 may include: the vehicle operating parameters are updated in response to an indication of an undesirable evaporative emission from the fuel system and/or the evaporative emission system. More particularly, the canister purge schedule may be updated to allow for more frequent purging operations to reduce evaporative emissions that may be released to the atmosphere. Further, to reduce the amount of undesirable evaporative emissions that may escape to the atmosphere, the vehicle may be scheduled to operate in an electric mode of operation more frequently (e.g., whenever possible) to minimize the undesirable evaporative emissions. Method 900 may then end.

Turning to fig. 10, an exemplary timeline 1000 for an EONV test according to the methods described herein with respect to fig. 8-9 and applicable to the systems described herein with reference to fig. 1-2 is shown. The timeline 1000 includes a curve 1005 that indicates a start or shut down state of a vehicle engine over time. The timeline 1000 also includes a curve 1010 that indicates whether conditions for conducting an EONV test are met (yes) or not (no) over time. The timeline 1000 also includes: a curve 1015 indicating an open or closed state of a Canister Vent Valve (CVV) (e.g., 297) over time; and a curve 1020 indicating an open or closed status of a Canister Purge Valve (CPV) (e.g., 261) over time. The timeline 1000 also includes a curve 1025 indicating pressures in the fuel system and the evaporative emissions system over time. The pressure in the fuel system and the evaporative emissions system may be monitored via a fuel tank pressure sensor (FTPT) (e.g., 291), and the pressure may be at atmospheric pressure (atm), either positive (+) or negative (-) relative to atmospheric pressure. Line 1026 represents a positive pressure threshold that, if reached, may indicate the absence of undesirable evaporative emissions. Similarly, line 1027 represents a negative pressure threshold (e.g., a vacuum threshold) that, if reached, may indicate the absence of an undesirable evaporative emission. The timeline 1000 also includes a curve 1030 that indicates whether undesirable evaporative emissions are indicated in the fuel system and the evaporative emissions system over time.

At time t0, the vehicle is in operation, with the engine combusting fuel, as indicated via curve 1005. When the vehicle is in operation, the conditions for conducting the EONV test are not indicated to be met, which is indicated by curve 1010. The CVV is in an open configuration and the CPV is closed. The tank pressure is at atmospheric pressure, which is indicated by curve 1025. In this exemplary timeline, it is understood that the vehicle system does not include an FTIV. However, where appropriate, the use of FTIV will be discussed below. Because no FTIV is included in this exemplary timeline 1000, the fuel system and evaporative emissions system pressures may be expected to approach atmospheric pressure when the CVV is open. Furthermore, the undesirable evaporative emissions are not indicated, as shown by curve 1030.

At time t1, the engine is off. While not explicitly shown, it is understood that in this exemplary timeline, engine shutdown occurs simultaneously with a key-off event. Further, at time t1, the condition for conducting the EONV test is indicated to be satisfied. For example, as discussed above, satisfying the condition may include: an indication that a key-off event occurs concurrently with a learned/predicted stop along the learned/predicted driving route, wherein the learned/predicted stop is indicated as being greater than a predetermined threshold duration (e.g., greater than 45 minutes). Further, as discussed above, meeting the conditions for conducting the EONV test may include: meeting a threshold length of engine run time prior to an engine shut-down event; a threshold amount of fuel in the fuel tank; a threshold battery charge; a heat rejection inferred value greater than a heat rejection inferred value threshold; threshold level of intake manifold vacuum, etc.

With the conditions for the EONV test satisfied at time t1, the CVV is commanded closed to seal the fuel system and the evaporative emissions system. Although not explicitly shown, it is understood that the vehicle controller may be left awake to conduct the EONV test. Where the vehicle includes an FTIV, the FTIV may be commanded open to couple the fuel system to the evaporative emissions system. Further, the CPV may be maintained closed (or commanded closed) in response to the conditions for conducting the EONV test being met.

With the fuel system and the evaporative emissions system sealed from the atmosphere and the engine intake, the pressure in the fuel system and the evaporative emissions system rises between times t1 and t2, as indicated by curve 1025. However, the pressure rise reaches a plateau between times t1 and t2 without reaching the predetermined positive pressure threshold, as represented by line 1026. Thus, at time t2, the CVV is commanded to open to relieve pressure in the fuel system and the evaporative emissions system. Thus, between times t2 and t3, with the CVV open, the pressure in the fuel system and the evaporative emissions system returns to atmospheric pressure, which is indicated by curve 1025. For vehicles that include an FTIV, the FTIV may be maintained open between times t2 and t 3.

At time t3, with the pressure in the fuel system and the evaporative emissions system returned to atmospheric pressure, the fuel system and the evaporative emissions system may be sealed again by commanding the CVV to close. It is understood that the CPV can be maintained closed and the FTIV (where included) can be maintained open. In the event that the fuel system and the evaporative emissions system are sealed from the atmosphere and engine air intake, vacuum builds up in the fuel system and the evaporative emissions system. Between times t3 and t4, vacuum builds, but does not reach the negative pressure threshold (e.g., vacuum threshold) represented by line 1027. It will be appreciated that at time t4, the predetermined duration for conducting the EONV test elapses or expires, thereby completing the EONV test. Because the negative pressure threshold is not reached during the vacuum build-up phase of the EONV test, an undesirable evaporative emission is indicated at time t 4. Such an indication may be stored, for example, at the controller, as discussed above, and the MIL may be illuminated, thereby indicating to the vehicle driver that service of the vehicle is required.

At time t4, where an indication of an undesirable evaporative emission is indicated, it is no longer an indication that the conditions for conducting the EONV test are satisfied, as indicated by curve 1010. Further, the CVV is commanded open to relieve fuel system and evaporative emissions system pressures. Where an FTIV is included in the vehicle, the FTIV may be commanded closed in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure. Thus, with the CVV commanded open, the pressure in the fuel system and the evaporative emissions system return to atmospheric pressure between times t4 and t 5.

Turning to fig. 11, a high-level flow diagram of an exemplary method 1100 for conducting an active vacuum suction evaporative emissions test is shown. More particularly, the active vacuum drawn evaporative emissions test may be scheduled only for learned/predicted stops during a learned/predicted driving cycle, where the learned/predicted stops are expected to be less than a predetermined duration (e.g., less than 45 minutes).

The method 1100 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 1100 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 1100 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as will be discussed below.

Method 1100 begins at 1105 and may include: indicating whether a key start event is indicated. As discussed above, the key-on event may include: the ignition key is utilized to start the vehicle in an engine start mode or an electric only operating mode. In other examples, the key-on event may include: depressing an ignition button on, for example, an instrument panel. Other examples may include: the key fob starts the vehicle in an engine start mode or an electric-only operating mode. If a key start event is not indicated at 1105, method 1100 may proceed to 1110 and may include: current vehicle operating parameters are maintained. For example, at 1110, method 1100 may include: the CPV, CVV, engine, etc. are maintained in their current configuration and/or current operating mode. Method 1100 may then end.

Returning to 1105, if a key start event is indicated, method 1100 may proceed to 1115. At 1115, method 1100 may include: driving route information is accessed. For example, accessing driving route information at 1115 may include: learned driving route information is retrieved from a vehicle controller. More particularly, the particular learned driving route may be indicated as being the same as the current driving route. In other words, the current driving route can be matched with the learned driving route with a high probability. The learned driving route may be matched to the current driving route based on a plurality of variables including vehicle location, time of day, date, day of the week, trajectory, and/or driver status. The identity of the driver may be entered by the driver or may be inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, and the like. In another example, the vehicle driver may enter one or more destinations into an in-vehicle navigation system (e.g., GPS), such that accessing driving route information at 1115 may include: driving route information input by a driver of the vehicle is accessed. In some examples, accessing driving route information may include: a lookup table, such as lookup table 420 depicted above at fig. 4B, is accessed in response to a particular driving route being identified with a high probability as the current driving route.

Proceeding to 1120, method 1100 may include: indicating whether any predicted/learned stops are indicated for a particular driving route including the current driving cycle. More particularly, at 1120, method 1100 may include: indicating whether any predicted/learned stops are expected to be less than a predetermined threshold duration, which may include a duration of less than 45 minutes, for example. If a predicted/learned stop is not indicated at 1120 that is expected to be less than a predetermined threshold duration, method 1100 may proceed to 1125 and may include: the driving cycle continues without the active vacuum suction evaporative emissions test. Method 1100 may then end. However, it is to be appreciated that in some examples, the active suction evaporative emissions test may be scheduled for a final destination stop, which may include a stop predicted/learned to be greater than 45 minutes, as will be discussed in greater detail below.

Returning to 1120, in response to one or more predicted/learned stops including a stop expected to be less than the predetermined duration, method 1100 may proceed to 1130 and may include: an active vacuum drawn evaporative emissions test is scheduled for one or more of the predicted/learned stops. In some examples, where more than one predicted/learned stop is indicated as being less than the predetermined duration of the current driving cycle, more than one active suction evaporative emissions test may be scheduled for the more than one predicted/learned stops. Alternatively, in other examples, only one active suction evaporative emissions test may be scheduled for one of one or more predicted/learned stops during the current driving cycle.

In response to scheduling one or more active draw evaporative emissions tests, method 1100 may proceed to 1135 and may include: the active vacuum suction evaporative emissions test was performed according to the method depicted at fig. 12. Briefly, an active vacuum suction evaporative emissions test may include: actively reducing pressure in the fuel system and the evaporative emissions system, and may further include: vacuum is delivered from the engine intake manifold to the fuel system and the evaporative emissions system under conditions in which the fuel system and evaporative emissions system are sealed from the atmosphere. Method 1100 may then end.

Turning now to FIG. 12, a high level flow chart of an exemplary method 1200 for conducting an active suction evaporative emissions test is shown. More particularly, the active suction evaporative emissions test may be scheduled for one or more stops during the driving route, where the one or more stops are predicted to be less than a predetermined threshold duration. Alternatively, in response to no stop during the driving route being predicted/learned to be less than the predetermined duration, in some examples, the active draw evaporative emissions test may be conducted at the final destination, or in some examples, the active draw evaporative emissions test may not be conducted for a particular driving route. In any event, the method for conducting the active purge evaporative emissions test is the same whether the active suction evaporative emissions test is conducted at a stop along the driving route or at the final destination of the driving route, and thus, the method for conducting the active suction evaporative emissions test is depicted herein in accordance with method 1200.

The method 1200 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 1200 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 1200 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as will be discussed below.

The method 1200 begins at 1205, and may include: indicating whether the conditions for the active suction evaporative emissions test are met. For example, satisfying the conditions for the active suction evaporative emissions test at 1205 may include: an indication that the vehicle is within a predetermined threshold time frame from reaching the learned/predicted stop, wherein the learned/predicted stop may include a stop expected to have a duration less than a predetermined duration (e.g., less than 45 minutes). Such an indication may be provided to the vehicle controller (e.g., 212) via an on-board navigation system (GPS), via a learned driving route stored at the controller in the form of a look-up table, or the like. Satisfying the conditions for performing the active suction evaporative emissions test may further include: an indication that the engine is in operation. In some examples, if all conditions for performing the active suction evaporative emissions test are met, but wherein the engine is not started, the engine may be pulled up (e.g., activated, turned on) so that the active suction evaporative emissions test may be performed.

If conditions for performing an active suction evaporative emissions test are not indicated as being met at 1205, method 1200 may proceed to 1210 and may include: current vehicle operating parameters are maintained. For example, maintaining current vehicle operating parameters may include: the CPV, CVV and FTIV (where included) are maintained in their current operating states. Further, maintaining the current vehicle operating parameters may include: such as maintaining the engine state in its current operating state. The method 1200 may then end.

Alternatively, in response to the conditions for performing the active suction evaporative emissions test being met at 1205, the method 1200 may proceed to 1215. At 1215, the method 1200 may include: the CVV is commanded to close to seal the fuel system and the evaporative emissions system from the atmosphere. In some examples where the vehicle includes an FTIV, the FTIV may be commanded open to relieve fuel system pressure prior to commanding the CVV to close. In response to sealing the fuel system and the evaporative emissions system from the atmosphere by commanding the CVV to close 1215, the method 1200 may proceed to 1220. At 1220, the method 1200 may include: the CPV cycle is cycled to deliver engine intake manifold vacuum to the fuel system and the evaporative emissions system. For example, the CPV may be cycled at a predetermined duty cycle. When the CPV cycle is emptied, the pressure in the fuel system and the evaporative emissions system may be monitored, for example, via a fuel tank pressure sensor (FTPT) (e.g., 291). For example, the CPV cycle may be cycled such that a predetermined target vacuum may be created in the fuel system and the evaporative emissions system. In some examples, the target vacuum may include a vacuum of, for example, -8InH2O, while in other examples, the target vacuum may be greater than or less than-8 InH 2O. Thus, proceeding to 1225, method 1200 may include: indicating whether the target vacuum has been reached. In response to the indication that the target vacuum has not been reached, method 1200 may return to 1220 and may include: the CPV continues to be cycled. As one example, the duty cycle of the CPV may be initially commanded to 100%, which may include commanding the CPV to an open state to quickly reach a target vacuum in the fuel system and the evaporative emissions system.

At 1225, in response to an indication that the target vacuum has been reached, method 1200 may proceed to 1230 and may include: the CPV cycle is cycled to maintain the fuel system and evaporative emissions system pressures at the target vacuum. More particularly, the duty cycle may be reduced such that the target vacuum is maintained without building up too much vacuum above the target vacuum.

Proceeding to 1235, the method 1200 may include: indicating whether a key-off event (e.g., a vehicle-off event) has occurred. Such events may be communicated to the controller, for example. If a key-off event is not indicated at 1235, method 1200 may return to 1230 and may include: the CPV continues to be cycled to maintain the target vacuum. Cycling the CPV to maintain the target vacuum may include: increasing the duty cycle in response to a pressure rise in the fuel system and the evaporative emissions system (e.g., becoming more positive relative to the target vacuum); or may include: the duty cycle is reduced in response to a pressure drop (e.g., becoming more negative relative to a target vacuum) in the fuel system and the evaporative emissions system. In this way, the target vacuum may be maintained until a key-off event is indicated. However, in some strategies, the cycle duty may be altered to prevent undesirable shifts in the engine combustion air-fuel ratio.

In response to indicating a key-off event at 1235, method 1200 may proceed to 1240. At 1240, the method 1200 may include: the fuel system and evaporative emission system are sealed by closing the CPV. Although not explicitly shown, it is understood that the CVV can be maintained in a closed configuration at 1240. Further, while not explicitly shown, it is understood that the vehicle controller may be maintained awake to continue testing.

Proceeding to 1245, the method 1200 may include: fuel system and evaporative emissions system pressures are monitored for a predetermined duration. More particularly, pressure bleed-off rises in the fuel system and the evaporative emissions system may be monitored and compared to a pressure bleed-off rise threshold or a pressure bleed-off rise rate threshold. For example, the pressure bleed-off rise threshold may include a pressure that, if reached, may indicate the presence of undesirable evaporative emissions with the fuel system and evaporative emissions system sealed. In other examples, the monitored pressure bleed-off rise rate may be compared to a pressure bleed-off rise rate threshold, and if the monitored pressure bleed-off rise rate is faster than the pressure bleed-off rise rate threshold, then an undesirable evaporative emission may be indicated. Both the pressure bleed-off rise threshold and/or the pressure bleed-off rise rate threshold may be adjusted based on fuel level and ambient temperature. In some examples, additionally or alternatively, both the pressure bleed-off rise threshold and/or the pressure bleed-off rise rate threshold may be adjusted as a function of BP and the estimated fuel temperature.

Thus, proceeding to 1250, method 1200 may include: whether the pressure bleed rise is greater than a predetermined pressure bleed rise threshold, or in some examples, whether the pressure bleed rise rate is greater than a predetermined pressure bleed rise rate threshold. In response to the pressure bleed-off rise not meeting or exceeding the pressure bleed-off rise threshold, or in response to the pressure bleed-off rise rate being less than a predetermined pressure bleed-off rise rate threshold, the method 1200 may proceed to 1255. At 1255, the method 1200 may include: indicating the absence of undesirable evaporative emissions in the fuel system and the evaporative emissions system. Such an indication may be stored, for example, at the controller.

In response to an indication that there are no undesirable evaporative emissions in the fuel system and the evaporative emissions system, method 1200 may proceed to 1260 and may include: a de-encapsulated fuel system and an evaporative emissions system. Unsealing the fuel system and evaporative emissions system at 1260 may include: for example, command the CVV to open. Where the vehicle includes an FTIV, the FTIV may be maintained open until the pressure in the fuel system and the evaporative emissions system reaches atmospheric pressure, and then may be commanded closed.

Proceeding to 1265, the method 1200 may include: the vehicle operating parameters are updated. In response to an indication that there are no undesirable evaporative emissions in the fuel system and the evaporative emissions system, updating the vehicle operating parameters at 1260 may include: current vehicle operating parameters are maintained. For example, the wash schedule may be maintained at its current schedule, and the engine operating state may be maintained, etc. The method 1200 may then end.

Returning to 1250, in response to an indication that the pressures in the fuel system and the evaporative emissions system have reached a predetermined pressure bleed-off rise threshold, or in response to an indication that the pressure bleed-off rise rate is greater than a predetermined pressure bleed-off rise rate threshold, method 1200 may proceed to 1270 and may include: indicating the presence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system. Such an indication may be stored, for example, at the controller. Further, the MIL may be illuminated on the vehicle dashboard, thereby alerting the vehicle driver to the need to service the vehicle.

Proceeding to 1260, the method 1200 may include: a de-encapsulated fuel system and an evaporative emissions system. As discussed above, the de-encapsulated fuel system and evaporative emissions system may include: the CVV is commanded to open to relieve pressure in the fuel system and the evaporative emissions system. Further, where the vehicle includes an FTIV, the FTIV may be maintained open until an indication that the pressure in the fuel system and the evaporative emissions system has reached atmospheric pressure, at which point the FTIV may be commanded closed.

Proceeding to 1265, the method 1200 may include: in response to the indication of the undesired evaporative emissions, the vehicle operating parameters are updated. For example, the canister purge schedule may be updated so that purging operations are performed more frequently to limit undesirable evaporative emissions that may otherwise escape to the atmosphere. In another example, the controller may update vehicle operating parameters such that the vehicle is propelled via an electric mode of operation whenever possible to reduce or avoid the release of undesirable evaporative emissions to the atmosphere. The method 1200 may then end.

Turning to fig. 13, an exemplary timeline 1300 for performing an active suction evaporative emissions test according to the method depicted herein with reference to fig. 11-12 and applicable to the system depicted herein with reference to fig. 1-2 is shown. The timeline 1300 includes a curve 1305 that indicates a start or stop state of the vehicle engine over time. The timeline 1300 also includes a curve 1310 that indicates whether the conditions for the active suction evaporative emissions test are met (yes) or not (no). The timeline 1300 also includes: a curve 1315 indicating an open or closed state of a Canister Vent Valve (CVV) (e.g., 297) over time; and a curve 1320 indicating the open or closed status of the Canister Purge Valve (CPV) (e.g., 261) over time. The timeline 1300 also includes a curve 1325 indicating fuel system and evaporative emissions system pressures over time. Pressure in the fuel system may be monitored via a fuel tank pressure sensor (FTPT) (e.g., 291), and the pressure may be at atmospheric pressure (atm), either positive (+) or negative (-) relative to atmospheric pressure. Line 1326 represents a target vacuum threshold, where the target is in response to a desired vacuum level in the fuel system and the evaporative emissions system meeting the conditions for conducting the active suction evaporative emissions test. Line 1327 represents a predetermined bleed-off rise pressure threshold that, if reached during the active suction evaporative emissions test, may indicate the presence of undesirable evaporative emissions. The timeline 1300 also includes a curve 1330 indicating whether undesirable evaporative emissions are indicated in the fuel system and/or the evaporative emissions system over time.

At time t0, the vehicle is in operation, with the engine combusting fuel to propel the vehicle, indicated by curve 1305. However, the conditions for the active draw evaporative emissions test have not been indicated to be met, which is indicated by curve 1310. The CVV is in an open configuration and the CPV is in a closed configuration. With the CVV open and the CPV closed, the pressure in the fuel system and the evaporative emissions system is near atmospheric pressure, indicated by curve 1325. Thus, it can be appreciated that in this exemplary timeline, the vehicle is not equipped with a Fuel Tank Isolation Valve (FTIV) (e.g., 252). However, where appropriate, the use of an FTIV will be discussed in terms of the exemplary timeline 1300. Further, no undesirable evaporative emissions are indicated, as shown by curve 1330.

At time t1, the condition for performing the active suction evaporative emissions test is indicated as being satisfied. As discussed above, meeting the conditions for the active suction evaporative emissions test may include: an indication that the vehicle is within a predetermined threshold time frame from reaching the learned/predicted stop, wherein the learned/predicted stop may include a stop expected to have a duration less than a predetermined duration (e.g., less than 45 minutes). Such an indication may be provided to a vehicle controller (e.g., 212) via an in-vehicle navigation system (e.g., GPS), via a learned driving route stored at the controller in the form of a look-up table, or the like. The satisfying of the conditions further includes: an indication that the engine is in operation.

When conditions for performing the active suction evaporative emissions test are indicated to be met at time t1, the CVV is commanded to close, indicated by curve 1315. In addition, the CPV is commanded open to deliver engine intake manifold vacuum to the fuel system and the evaporative emissions system. Where the vehicle includes an FTIV, the FTIV may be commanded open at time t1 such that the fuel system and the evaporative emissions system may be fluidly coupled to one another.

Where the CPV is commanded open (e.g., duty cycled at 100% duty cycle) so that intake manifold vacuum may be delivered to the fuel system and the evaporative emissions system, and where the fuel system and the evaporative emissions system are sealed from the atmosphere via the CVV in a closed configuration, vacuum may build up in the fuel system and the evaporative emissions system. Thus, between times t1 and t2, the pressures in the fuel system and the evaporative emissions system become more negative relative to atmospheric pressure. At time t2, the target vacuum threshold represented by line 1326 is indicated to be reached. However, the vehicle has not yet reached the predicted/learned destination, and thus, the target vacuum may be maintained until it is indicated that the vehicle has reached the predicted/learned destination. Thus, between times t2 and t3, the CPV is cycled at a rate less than 100% duty cycle such that the negative pressure in the fuel system and the evaporative emissions system is maintained at the target vacuum.

At time t3, engine shutdown is indicated. In this exemplary timeline, it can be appreciated that the engine shutdown event at time t3 corresponds to a key-off event, wherein the engine is deactivated. Thus, the controller may be indicated that the vehicle has reached the predicted/learned destination. Thus, at time t3, the CPV is commanded to close and the CVV is maintained closed. For vehicles equipped with an FTIV, it is understood that the FTIV may be maintained open at time t 3. With the engine off, CPV closed, and CVV closed, the target vacuum may be understood to be trapped in the fuel system and evaporative emissions system. As discussed above, in response to the target vacuum being formed in the fuel system and the evaporative emissions system, a pressure bleed-off rise (or in some examples, a pressure bleed-off rise rate) may be monitored in the fuel system and the evaporative emissions system such that a determination may be made as to the presence or absence of undesirable evaporative emissions in the fuel system and the evaporative emissions system.

Thus, between times t3 and t4, the pressure in the fuel system and the evaporative emissions system may be monitored, for example, via the FTPT. At time t4, the pressure in the fuel system reaches a predetermined bleed-off rise pressure threshold, represented by line 1327. When the pressure in the fuel system and the evaporative emissions system reaches a predetermined bleed-off rise pressure threshold, indicating an undesirable evaporative emissions, this curve 1330 shows. Such an indication may be stored, for example, at the controller. Further, the MIL may be illuminated on the vehicle dashboard, thereby alerting the vehicle driver to the need to service the vehicle. In the event that an undesirable evaporative emission is indicated in the vehicle fuel system and/or evaporative emission system, the satisfaction of the conditions for the active suction evaporative emission test is no longer indicated, which is illustrated by curve 1310. Further, the CVV is commanded to open to relieve pressure in the fuel system and the evaporative emissions system. Where the vehicle includes an FTIV, the FTIV may be commanded closed in response to the pressure in the fuel system and the evaporative emissions system reaching atmospheric pressure. With the CVV open, the pressure in the fuel system and the evaporative emissions system return to atmospheric pressure between times t4 and t 5.

While the above description has discussed methods for scheduling and conducting tests for undesirable evaporative emissions based on predicted/learned hill sections, predicted/learned stop durations, and predicted/learned final destinations, such descriptions are discussed independently of one another. However, in some examples, for a particular driving cycle, an optimized evaporative emissions test schedule may be generated based on a combination of information relating to predicted/learned hill sections, predicted/learned stop durations, and predicted/learned final destinations. For example, in some examples, BP change evaporative emission tests may be scheduled for a driving route based on predicted/learned hill segments, and EONV tests may be scheduled for a final destination of the same driving route. In other examples, the active draw evaporative emissions test may be scheduled for stops of less than a predetermined duration (e.g., less than 45 minutes) during a driving route, and the EONV test may be scheduled for a final destination for the same driving route. Such examples are intended to be illustrative, not limiting. For example, any combination of performing one or more BP change evaporative emission tests, one or more active suction tests, and one or more EONV tests may be utilized based on the predicted/learned driving route information.

Further, in some examples, variables such as ambient temperature, local weather conditions, predicted/learned heat rejection during predicted/learned driving cycles, fuel levels, etc. may be taken into account when generating an optimized evaporative emission test schedule for a particular driving route. Such examples are discussed in more detail below.

Turning to fig. 14, an exemplary method 1400 for generating an optimized evaporative emissions test schedule for a predicted/learned driving route is illustrated. More particularly, the vehicle controller may retrieve information about learned driving route information and may schedule one or more tests for the undesired evaporative emissions during the predicted/learned driving route such that appropriate tests for the undesired evaporative emissions may be conducted at appropriate points/locations with respect to a given learned driving program. In some examples, as will be discussed below, scheduling one or more tests for undesirable evaporative emissions may be further based on an indicated ambient temperature, local weather conditions, fuel level, expected heat rejection profile during a current driving cycle, and the like, as will be discussed in detail below.

The method 1400 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 1400 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing the method 1400 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as discussed above.

Method 1400 begins at 1405 and may include: indicating whether a key start event is indicated. As discussed above, the key-on event may include: the ignition key is utilized to start the vehicle in an engine start mode or an electric only operating mode. In other examples, the key-on event may include: depressing an ignition button on, for example, an instrument panel. Other examples may include: the key fob starts the vehicle in an engine start mode or an electric-only operating mode. If a key start event is not indicated at 1405, the method 1400 may proceed to 1410 and may include: current vehicle operating parameters are maintained. For example, at 1410, method 1400 may include: the CPV, CVV, engine, etc. are maintained in their current configuration and/or current operating mode. The method 1400 may then end.

Returning to 1405, if a key start event is indicated, the method 1400 may proceed to 1415. At 1415, the method 1400 may include: driving route information is accessed. For example, accessing driving route information at 1415 may include: learned driving route information is retrieved from a vehicle controller. More particularly, the particular learned driving route may be indicated as being the same as the current driving route. In other words, the current driving route can be matched with the learned driving route with a high probability. The learned driving route may be matched to the current driving route based on a plurality of variables including vehicle location, time of day, date, day of the week, trajectory, and/or driver status. The identity of the driver may be entered by the driver or may be inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, and the like. In another example, a vehicle driver may enter one or more destinations into an in-vehicle navigation system (e.g., GPS) such that accessing driving route information at 1415 may include: driving route information input by a driver of the vehicle is accessed. In some examples, accessing driving route information may include: a lookup table, such as lookup table 420 depicted above at fig. 4B, is accessed in response to a particular driving route being identified with a high probability as the current driving route.

Proceeding to 1420, the method 1400 may include: information about the predicted/learned hill section, the duration of the predicted/learned stop, and the predicted/learned final destination is retrieved. More particularly, at 1420, method 1400 may include: indicating whether any segment of the current driving cycle includes an altitude change in which the pressure change production may be greater than a predetermined pressure change production threshold for the sealed fuel system and evaporative emissions system, as discussed above with respect to fig. 5. Further, at 1420, method 1400 may include: indicating whether any predicted/learned stops are indicated for a particular driving route including the current driving cycle. For example, at 1420, method 1400 may include: indicating whether any predicted/learned stops are greater than a predetermined threshold duration (e.g., greater than 45 minutes), as discussed above with respect to fig. 8. Still further, at 1420, method 1400 may include: indicating whether any predicted/learned stops of the current driving cycle are predicted/learned to be less than a predetermined threshold duration (e.g., less than 45 minutes), as discussed above with respect to fig. 11.

Proceeding to 1425, the method 1400 may include: information about the ambient temperature as indicated, for example, via an ambient temperature sensor is retrieved. At 1425, the method 1400 may further include: information about local weather conditions is retrieved. As one example, the local weather conditions may be communicated to the controller via an in-vehicle navigation system (e.g., GPS), via wireless communication over the internet, or any other conventional means of communicating the local weather conditions to the vehicle controller. For example, when the controller may make a determination as to whether to conduct an EONV test or an active suction evaporative emissions test, ambient temperature and local weather conditions (e.g., wind, rain, snow, etc.) may be taken into account, as will be discussed in further detail below. Still further, at 1425, the method 1400 may include: the fuel level is indicated via, for example, a fuel level sensor (e.g., 234). For example, knowledge of fuel levels may be utilized to predict heat rejection profiles for particular segments of a predicted/learned driving program. As one example, a heat rejection override (HRI) threshold used to determine whether an EONV test is performed at a particular stop may be adjusted based on the predicted fuel level. For example, based on the currently indicated fuel level and the predicted/learned driving route, inferences may be made regarding the fuel level in a particular predicted/learned parking lot bin. Such information may be utilized to predict whether the HRI may be above the HRI threshold at a particular predicted/learned stop, and may be utilized in order to determine whether to schedule/conduct an EONV test as compared to an active suction evaporative emissions test.

Proceeding to 1430, the method 1400 may include: an optimized expected evaporative emissions test schedule is generated for the current predicted/learned driving route. For example, the vehicle controller may process stored data including: the number of predicted/learned hill sections that facilitate the BP change evaporative emission test, the number of predicted/learned stops for durations greater than a predetermined threshold duration (e.g., >45 minutes), and the number of predicted/learned stops for durations less than a predetermined threshold duration (e.g., <45 minutes). The vehicle may further process data including ambient temperature, fuel level, local weather conditions, predicted heat rejection profile, and the like. Based on this combination of data, the method 1400 may generate an optimized expected evaporative emissions test schedule for the current predicted/learned driving route.

Examples of optimized undesirable evaporative emissions test schedules will be discussed herein. It is understood that such examples are intended to be illustrative, and that examples not specifically discussed, which are within the scope of the present disclosure, may be performed according to the methods depicted herein without departing from the scope of the present disclosure.

In one example, consider two stops predicted to have a duration greater than a predetermined threshold (e.g., >45 minutes). Although the EONV test may be scheduled for two stops because the test is likely to be completed, one stop may be prioritized over another based on the expected (e.g., learned) amount of heat rejection (e.g., heat rejection profile) for each of the predicted/learned stops. For example, prior to a stop, the learned driving route information may indicate that the vehicle is generally operating with a low level of aggressiveness, under low load, and the like. Thus, at such a stop, the amount of heat rejected may be predicted to be below the HRI threshold. In some examples, fuel levels, weather conditions, ambient temperature, etc. may be further utilized in order to generate an accurate prediction of the heat rejection profile for such a stop. If the predicted heat rejection profile is indicated as being below the HRI threshold, then the EONV test may not be scheduled for such parking. Conversely, an active suction evaporative emissions test may be scheduled for this particular shutdown, such that for the active suction evaporative emissions test, the likelihood that the test provides robust results may be higher. In other examples, in response to the predicted heat rejection profile being less than the HRI threshold, testing for undesirable evaporative emissions may not be scheduled for this particular shutdown. Alternatively, for an exemplary stop (where heat rejection is predicted to be above the HRI threshold for this particular stop), an EONV test may be scheduled instead of the active draw evaporative emissions test.

Similar logic may be applied to final destination parking. For example, in some examples, in response to reaching the final destination, it may be predicted (based on the variables discussed above, including ambient temperature, weather conditions, fuel levels, learned driving habits, etc.) that the heat rejection may be below the HRI threshold. In such an example, an active suction evaporative emissions test may be scheduled for the final destination, rather than an EONV test. In other examples, where heat rejection may be predicted to be above the HRI threshold for the predicted/learned final destination, an EONV test may be conducted instead of an active draw evaporative emissions test.

With respect to testing for undesirable evaporative emissions during a hill segment in which the predicted vacuum/pressure production of the sealed fuel system and evaporative emissions system is indicated to be greater than a predetermined pressure change production threshold, testing may be scheduled for only those hill segments that are: wherein it is further indicated that after a hill section, a predetermined duration or length of vehicle travel is predicted/learned to be substantially flat. In other words, if the vehicle quickly encounters another hill segment in response to completion of a particular hill segment, subsequent BP changes due to subsequent hills may affect the interpretation of the bleeder rise or bleeder fall pressure analysis results. Thus, generating an optimized undesired evaporative emissions test schedule at 1430 may include: in response to a particular hill section being followed quickly by another hill section, the hill section in which testing may be performed is excluded.

In some examples, more than one test for undesirable evaporative emissions may be scheduled for a particular predicted/learned driving cycle. For example, for a predicted/learned driving cycle having one or more hill sections that are favorable for performing a BP-change evaporative emission test, such a test may be scheduled for one or more of the hill sections. If such predicted/learned driving cycle also includes one or more predicted stops that facilitate the EONV test, such tests may be scheduled for one or more of the stops. Similarly, if such predicted/learned driving cycle also includes one or more predicted stops that facilitate active suction evaporative emission testing, such testing may be scheduled for one or more of the stops. Thus, some driving routes may include any combination of an EONV test, an active suction evaporative emissions test, and/or a BP varying evaporative emissions test. Alternatively, some driving routes may include only one test, such as an EONV test or an active suction test performed at the final destination. Such examples may include driving routes that do not have parking or hill sections that facilitate any evaporative emission testing. Still further, in some examples, evaporative emissions testing may be scheduled only for parking or hill segments predicted to be most likely to result in robust results, although more than one parking or more than one hill segment may be advantageous for evaporative emissions testing.

Proceeding to 1435, method 1400 may include: tests for the undesirable evaporative emissions are scheduled based on the optimized test schedule generated at 1430. Where a test for undesirable evaporative emissions is scheduled, method 1400 may proceed to 1440 and may include: appropriate tests for undesirable evaporative emissions are conducted at appropriately scheduled times or locations. For example, the BP change evaporative emissions test may be conducted as discussed above with respect to fig. 6, the EONV test may be conducted as discussed above with respect to fig. 9, and the active suction evaporative emissions test may be conducted as discussed above with respect to fig. 12. The method 1400 may then end.

As mentioned above, it is recognized herein that in addition to or in lieu of testing for the presence or absence of undesirable evaporative emissions, the creation of a vacuum in a sealed fuel system during downhill travel of a vehicle may serve another purpose. In particular, in response to a vacuum being created in the sealed fuel system as a result of the vehicle being lowered to altitude, upon de-sealing the fuel system, the fuel system may draw in atmospheric air, which may vent fuel vapor from the fuel vapor storage canister (e.g., 222). Thus, fuel vapor vented from the fuel vapor storage canister may be returned to the fuel tank where it may condense into liquid fuel. In this manner, the canister may be at least partially purged in response to unsealing the fuel system (while the vacuum remains in the fuel system) after the fuel system is sealed during the particular segment in which the vehicle is traveling downhill. The canister purge event discussed herein that returns fuel vapor from the canister to the fuel tank is referred to as a passive purge. Alternatively, the purging of the canister via application of engine manifold vacuum to the canister in order to draw fuel vapor from the canister for combustion in the engine, as discussed herein, may be referred to as active purging.

As discussed above with respect to fig. 3, the vehicle controller may learn over time the particular driving route traveled by the vehicle. In some examples, such learned routes may be associated with a particular vehicle driver. In other examples, a vehicle driver or passenger may enter a destination into an in-vehicle navigation system (e.g., GPS) and may select a particular route to the destination.

Some vehicles may participate in a car sharing model, where a car sharing model refers to a car rental model in which people can rent a vehicle for a short time. For example, a customer may pay for use of such a vehicle on an hourly basis, in terms of miles driven, and the like. For the automobile sharing model, a particular destination and a desired route may be provided via a customer requesting use of a particular vehicle. Such destinations and desired routes may be provided via a software application that coordinates an automobile sharing model, via a human-machine interface in the vehicle, and so forth. In some examples, vehicles participating in the automobile sharing model may include autonomous vehicles that may be configured with the ability to navigate to a requested destination without input from the vehicle driver. In some examples, a controller of the autonomous vehicle may select a desired destination and a desired route from a menu or group of potential destinations/routes.

Whether learned or selected, a driving route known in advance may allow for predicting a particular segment of such a driving route where the vehicle may travel downhill for a length and/or duration that enables an estimation of the amount of vacuum that may be expected to form in the sealed fuel system during the descent. Such an estimation may be based on the fuel level in the fuel tank. As discussed above, such knowledge may enable scheduling of tests to be conducted for the presence or absence of undesirable evaporative emissions, provided that a predicted route includes one or more altitude changes sufficient to produce a desired pressure change in the sealed fuel system.

Thus, it is recognized herein that knowing ahead of time one or more segments in which the vehicle is predicted to experience a decrease or decrease in altitude may allow for passive washing operations by: the fuel system is sealed during the descent of the altitude and then de-sealed during and/or after the descent of the altitude to passively purge fuel vapors from the canister to the fuel tank. In the case of passive purging during a particular driving cycle, the active purging event may be adjusted accordingly based on the passive purging. For example, if passive purging also occurs during a particular driving cycle, the aggressiveness of active purging may be lower. With respect to being less aggressive, it is to be appreciated that active purging may be initiated at a lower CPV (e.g., 261) duty cycle and/or that ramping up or increasing the rate of the CPV cycle duty during an active purging event may be performed at a lower rate than a more aggressive purging event in which the ramping of the duty cycle is performed at a faster rate (e.g., which may occur for a driving cycle that does not otherwise include passive purging). In some examples, passive purging may adequately purge the canister such that active purging during the same driving cycle may be avoided altogether. Such examples are discussed in more detail below. It will be appreciated that in some examples, passive purging may be scheduled in advance for a particular driving cycle. In other examples, the passive purge may be performed after a test for the presence or absence of undesirable evaporative emissions that relies on the formation of a vacuum in the fuel system due to a decrease in vehicle altitude. In some examples, the aggressiveness of the active purge may be adjusted for active purges that occur in the driving cycle before the scheduled passive purges. In other examples, the aggressiveness of the active wash may be adjusted for active washes that occur after a passive wash event in the driving cycle.

Accordingly, turning to FIG. 15, an exemplary method 1500 for adjusting aggressiveness of an active purge operation is shown. In particular, the method 1500 may be used to: in response to an indication of the absence of undesirable evaporative emissions from the vehicle fuel system and evaporative emissions system, wherein the test for the presence or absence of undesirable evaporative emissions is conducted using a vacuum developed in the fuel system/evaporative emissions system based on an altitude change predicted ahead of vehicle degradation, a subsequent active purging of the canister is controlled to be less aggressive than would otherwise be arranged.

The method 1500 will be described with reference to the systems described herein and shown in fig. 1-2, but it should be understood that similar methods may be applied to other systems without departing from the scope of the present disclosure. The method 1500 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing method 1500 and the remaining methods included herein may be executed by a controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of an engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as discussed above.

The method 1500 begins at 1505 and includes: testing for the presence or absence of undesirable evaporative emissions was conducted in accordance with the method 600 depicted at fig. 6. It is to be understood that step 1505 refers to a test in which the vehicle lowers its altitude, rather than a test for the vehicle raising its altitude. Briefly, the method of fig. 6 includes: the fuel system and the evaporative emissions system are sealed just prior to the learned/predicted or scheduled altitude decrease, thereby creating a vacuum in the sealed fuel system and evaporative emissions system as the altitude decreases, and then the pressure bleed-off rise is monitored to ascertain the presence or absence of the undesirable evaporative emissions.

Thus, at 1510, method 1500 includes: whether evaporative emissions are undesirable is indicated by such testing. If an indication of undesirable evaporative emissions is indicated, it is understood that the pressure bleed-off rise in the sealed fuel system and the evaporative emissions system respectively rises at a rate greater than a predetermined rate-of-pressure threshold and/or to a level greater than a predetermined pressure threshold. In other words, the pressure bleed-off rise in the event that undesirable evaporative emissions are indicated may be substantial, and thus the amount of vacuum in the sealed fuel system and evaporative emissions system may be greatly reduced during the process of conducting diagnostics.

Because any level of vacuum initially present in the sealed fuel system and the evaporative emissions system is greatly reduced if an undesirable evaporative emission is indicated, when the fuel system and the evaporative emissions system are unsealed after diagnostics, there is likely to be no significant residual vacuum for effective passive canister purging. While the canister may be passively purged, at least to some extent, it may not be desirable to adjust the aggressiveness of subsequent active purges of the same driving cycle because the vacuum level is greatly reduced if an undesirable evaporative emission is indicated.

As an illustrative example, turning back to FIG. 7 between times t1 and t4 of time line 700, a test for undesirable evaporative emissions is shown being conducted, wherein the vacuum for the test is provided by sealing the fuel system and the evaporative emissions system just prior to downhill travel of the vehicle. Between times t3 and t4, the pressure bleed rise (see curve 730) remains below the pressure bleed rise threshold (see line 732). Thus, at time t4, when the fuel system and the evaporative emissions system are de-encapsulated, a substantial amount of vacuum still exists in the fuel system and the evaporative emissions system, such that relieving the vacuum by drawing fresh air through the fuel vapor canister to the fuel tank may result in an effective passive purge. However, although not explicitly shown at fig. 7, in the event that the presence of an undesired evaporative emission is indicated, it will then be determined that the pressure bleed-off rises above the pressure bleed-off rise threshold, and thus the amount of vacuum present for passively purging the canister will be much less than if the undesired evaporative emission is not indicated. Thus, passive purging may be ineffective in indicating an undesirable evaporative emission, and thus, it may be desirable to continue active purging without adjusting aggressiveness.

Thus, returning to fig. 15 assuming that an undesirable evaporative emission is indicated at 1510, method 1500 may proceed to 1515 and may include: the aggressiveness of any subsequent canister purge event is not adjusted for the remainder of the current drive cycle. In other words, the current setting of active canister purge events may be maintained, at least in terms of aggressiveness. Maintaining the current setting of aggressiveness may include: maintaining a duty cycle rate of the canister purge valve when purging is initiated, and may further include: maintaining a rate at which the canister purge valve duty cycle ramps up during purging. In some examples, the rate may vary based at least in part on canister loading conditions, e.g., as learned during a wash event.

With canister purge aggressiveness maintained at 1515, the method 1500 may proceed to 1520 and may include: the canister is actively cleaned according to the method of FIG. 16in response to an indication that an active cleaning condition is satisfied during a current driving cycle. Such active cleaning events are discussed in further detail below with respect to fig. 16.

Alternatively, returning to 1510, in response to an indication that undesired evaporative emissions are not indicated after conducting a test that relies on a vacuum created in the fuel system and evaporative emissions system via a vehicle lowering the altitude, method 1500 may proceed to 1525. At 1525, the method 1500 may include: the aggressiveness of subsequent active wash events is adjusted for the current driving cycle. In particular, because of the indication of the absence of undesirable evaporative emissions, a significant amount of vacuum may be maintained in the sealed fuel system and evaporative emissions system after testing is conducted, such that the unsealed fuel system and evaporative emissions system may be used to effectively passively purge the canister of adsorbed fuel vapors. Thus, the aggressiveness of future active purge events in the current driving cycle may be low, as the canister is likely to have been substantially purged of stored fuel vapor.

Accordingly, at 1525, the controller may adjust the aggressiveness by commanding a lower initial rate of duty cycle of the canister purge valve for starting the purge of the canister. The controller may further adjust the aggressiveness by decreasing the rate at which the canister purge valve duty cycle is increased or ramped up during a particular active purge event. The adjusted rate may vary according to canister loading conditions as learned over time during a particular active purge event, but the adjusted rate may be understood to include a slower rate than if the duty cycle rate were not adjusted (where an undesirable evaporative emission is indicated). In some examples, in response to unsealing the fuel system, a canister temperature sensor positioned in the canister may be used to monitor a temperature change of the canister at a time after indicating the absence of the undesired evaporative emissions. In particular, unsealing a fuel system containing a vacuum may result in passive purging of the canister, wherein fuel vapors are desorbed back into the fuel tank. Desorption of fuel vapor can cause the temperature of the canister to drop, which can be used to indicate canister loading conditions. Thus, in some examples, the adjustment aggressiveness at 1525 may be varied according to the loading state of the canister. For example, the less load the canister is instructed to do after passive cleaning, the lower the initial rate of the CPV duty cycle, and the lower the ramping rate of the rate at which the CPV duty cycle increases during active cleaning.

Where such instructions for future active flush events are stored or updated via the controller, the method 1500 may proceed to 1520. At 1520, the method 1500 may include: the canister is actively cleaned according to the method of fig. 16.

Accordingly, a system for a vehicle may include a fuel system including a fuel tank selectively fluidly coupled to a fuel vapor storage canister positioned in an evaporative emission system via a fuel tank isolation valve, and wherein the fuel vapor storage canister is selectively fluidly coupled to atmosphere via a canister vent valve and selectively coupled to an intake port of an engine via a canister purge valve. The system may also include an in-vehicle navigation system. The system may also include a controller having computer-readable instructions stored on a non-transitory memory that, when executed, cause the controller to: in response to an indication that the vehicle is within a threshold distance of a reduction in altitude predicted to result in at least a predetermined vacuum level being formed in the fuel system and evaporative emissions as indicated via the on-board navigation system, coupling the fuel system to the evaporative emissions system via commanding the fuel tank isolation valve to open and then sealing the fuel system and the evaporative emissions system via commanding the canister vent valve to close. The controller may store further instructions for maintaining a target vacuum in the fuel system and the evaporative emissions system during the altitude decrease via cycling the canister vent valve duty. The controller may store further instructions for conducting a test for the presence or absence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system via monitoring a pressure bleed-off rise in the fuel system and the evaporative emissions system sealed from the atmosphere just after the altitude decrease. The controller may store further instructions for unsealing the fuel system and the evaporative emissions system in response to a determination of the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system. The controller may store additional instructions for adjusting the aggressiveness of subsequent active purge operations of the fuel vapor storage canister based on the indication of the presence or absence of the undesired evaporative emissions.

In such a system, the controller may store further instructions for indicating the presence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system in response to the pressure bleed rising above a predetermined pressure bleed rise threshold and/or in response to the pressure bleed rise rate exceeding a predetermined pressure bleed rise rate, for a predetermined duration.

In such a system, the controller may store additional instructions for actively purging the canister during a subsequent active purge operation via commanding the canister vent valve to open and cycling the canister purge valve to duty cycle for applying intake manifold vacuum to the fuel vapor storage canister to purge fuel vapor stored in the fuel vapor storage canister to the engine for combustion. Adjusting the aggressiveness of the subsequent active purge operation may comprise: initiating the subsequent active purge operation at a lower duty cycle of the canister purge valve and reducing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the indication of the absence of the undesired evaporative emissions as compared to initiating the subsequent active purge operation at a higher duty cycle of the canister purge valve and increasing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the presence of the undesired evaporative emissions.

Such a system may also include a temperature sensor positioned in the fuel vapor storage canister. The controller may store further instructions for monitoring a change in temperature of the fuel vapor storage canister to indicate a loading state of the canister in response to: unsealing the fuel system and the evaporative emissions system in response to the determination made as to the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, wherein unsealing the fuel system and the evaporative emissions system passively purges fuel vapor stored in the fuel vapor storage canister back to the fuel tank. In such a system, the controller may store further instructions for adjusting the aggressiveness of the subsequent active wash operation as a function of the loading state of the canister.

Turning now to FIG. 16, an exemplary method 1600 for performing an active purge of a fuel vapor storage canister is depicted. Method 1600 may result from step 1520 of method 1500. Thus, the method 1600 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for implementing method 1600 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as discussed above and as further discussed below.

Method 1600 begins at 1605 and includes: indicating whether the conditions for actively cleaning the canister are met. Satisfying the condition may include: an engine start state; a request to clean the canister has been indicated via the controller; a threshold level of engine intake manifold vacuum, wherein the threshold level is sufficient to effectively clean the canister; an estimated or measured value of the temperature of an emission control device, such as a catalyst, is higher than a predetermined temperature associated with catalytic operation (commonly referred to as a light-off temperature), or the like. If conditions for cleaning the canister are not indicated to be met at 1605, method 1600 may proceed to 1610. At 1610, method 1600 may include: and maintaining the current vehicle working condition. For example, such conditions may be maintained if the vehicle is propelled via an energy source other than the engine (e.g., electric propulsion). Such operation may continue if the vehicle is operating under boosted engine operation. If the vehicle is not operating, the vehicle off condition may be maintained. The method 1600 may then end.

Returning to 1605, in response to an indication that the purge condition is satisfied, method 1600 may proceed to 1615. At 1615, the method 1600 may include: indicating whether the cleaning aggressiveness has been adjusted, as discussed above with respect to method 1500. If it has not been indicated that the cleaning aggressiveness has been adjusted, method 1600 may proceed to 1620. At 1620, method 1600 may include: the CPV duty cycle is commanded to an unregulated duty cycle. In other words, the duty cycle of the CPV is commanded to a duty cycle stored at the controller that corresponds to an aggressive canister cleaning program. Although not explicitly shown, at 1620, method 1600 may include: the CVV is commanded to open or maintain the CVV open, and the FTIV is commanded to close or maintain the FTIV closed.

Proceeding to 1625, method 1600 may include: and (5) cleaning the filter tank. Cleaning the canister may include the steps of: ramping up the duty cycle of the CPV according to the unregulated CPV ramping rate and maintaining the desired air-fuel ratio. In particular, cleaning the canister may comprise: an air-fuel ratio is indicated via, for example, a proportional-integral feedback controller coupled to a two-state exhaust gas oxygen sensor, and a base fuel command is generated in response to the air-fuel indication and a measurement of the inducted air flow. To compensate for the purge vapor, a reference air-fuel ratio associated with engine operation without purging may be subtracted from the air-fuel ratio indication and a resulting error signal (compensation factor) generated. Thus, the compensation factor may represent a learned value that is directly related to fuel vapor concentration and may be subtracted from the base fuel command to correct for the introduction of fuel vapor. The duration of the purge operation may be based on a learned value of the vapor (or a compensation factor) such that the purge may be ended when no significant hydrocarbons are indicated in the vapor (the compensation is substantially zero).

The steam introduced into the engine may be controlled according to the duty cycle of the CPV, and it is understood that as the wash event progresses, the CPV duty cycle may be ramped up to higher and higher duty cycles in order to effectively clean the canister. Because the purge aggressiveness is not adjusted, it can be appreciated that the CPV duty cycle ramp rate comprises the unadjusted ramp rate at 1625. In other words, the ramp rate of CPV duty cycle increase may include a ramp rate stored at the controller that corresponds to an aggressive canister cleaning program.

Thus, proceeding to 1630, method 1600 may include: indicating whether the canister loading condition is below a threshold loading level, where it is understood that no significant fuel vapor is being introduced to the engine. In some examples, additionally or alternatively, such a determination may be indicated based on a change in temperature at the canister monitored by a canister temperature sensor (e.g., 232). For example, when the temperature of the canister is no longer changing, it can be inferred that the vapor is no longer desorbing from the canister.

If at 1630 it is indicated that the canister loading status is not below the threshold loading level, method 1600 may return to 1625 where a canister purge may be performed. Alternatively, in response to an indication that the canister loading status is below the threshold loading level, method 1600 may proceed to 1635. At 1635, the method 1600 may include: the vehicle operating conditions are updated to reflect the wash event. In particular, the canister loading status may be updated at the controller and the canister purge schedule may be updated to reflect the fact that the canister purge operation has been completed. For example, another canister purge operation may not be scheduled for the current driving cycle unless another diagnostic is made that loads the canister to an appreciable amount, or in response to a refueling event, etc. The method 1600 may then end.

Returning to 1615, in response to the cleaning aggressiveness having been adjusted because the test at method 1500 for the undesired evaporative emissions has indicated that there are no undesired evaporative emissions, thereby enabling an effective partial cleaning of the canister, method 1600 may proceed to 1640. At 1640, method 1600 may include: the command CPV cycles the duty at an adjusted rate that is stored at the controller and that includes a duty cycle rate that is lower than the initial rate of the CPV duty cycle for the aggressive purge operation.

In some examples, the amount by which the duty cycle is reduced compared to the duty cycle for an aggressive purging operation may vary depending on the amount of passively purging the canister. For example, the greater the amount of fuel vapor passively purged, the lower the initial duty cycle of the CPV may be commanded. Such a determination may be made, for example, at step 1525 of method 1500 via the controller, and may be implemented at step 1640 of method 1600.

Proceeding to 1645, method 1600 may include: the canister is cleaned substantially as described above for step 1625, except that the CPV duty cycle is ramped up at a regulated CPV duty cycle ramp rate during cleaning. Similar to the adjusted initial CPV duty cycle, the rate at which the CPV duty cycle ramps up at 1625 can be varied according to the amount of passively cleaned canister. For example, the greater the amount of passively cleaned canister, the lower the rate at which the CPV duty cycle can be ramped up (increased).

Proceeding to 1650, similar to step 1630, the method 1600 may include: indicating whether the canister loading status is below the threshold loading level, as discussed above. If not, cleaning the canister may proceed as discussed at step 1645. In response to indicating that the canister loading state is below the threshold loading level, method 1600 may proceed to 1635, where the vehicle operating conditions may be updated. Similar to the discussion above, updating vehicle operating conditions may include: the method further includes updating a canister loading status at the controller and updating a canister purge schedule to reflect the most recent canister purge event. The method 1600 may then end.

It will be appreciated that less aggressive cleaning of the canister may reduce the likelihood of engine surge and/or stall compared to an aggressive cleaning procedure. Thus, it may be desirable to combine one or more passive wash operations of a driving cycle with one or more less aggressive active wash operations whenever possible.

Although the above description with respect to fig. 15-16 relies on performing scheduled tests for undesirable evaporative emissions and performing partial purging as a result of de-energizing the fuel system and evaporative emissions system after performing the tests, there may be opportunities to specifically schedule passive purging operations similar to scheduling tests for undesirable evaporative emissions, as long as the route of the particular driving cycle is known in advance.

Accordingly, turning to fig. 17, an exemplary method 1700 is depicted that illustrates a method for scheduling a passive wash operation for a particular driving cycle. The method 1700 may be implemented by a controller (such as the controller 212 in fig. 2) and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for performing the method 1700 may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system.

Method 1700 begins at 1705 and may include: indicating whether a key start event is indicated (see step 505 of fig. 5). If a key start event is not indicated, method 1700 may proceed to 1710 where the current vehicle operating parameters are maintained. For example, such conditions may be maintained if the vehicle is already in an operating state, propelled via the engine, the motor, or some combination of the two. Alternatively, such vehicle shutdown parameters may be maintained if the vehicle is not operating. Method 1700 may then end.

Returning to 1705, if a key start event is indicated, method 1700 may proceed to 1715. At 1715, method 1700 may include: driving route information is retrieved. As discussed above (see step 515 of method 500), in one example, driving route information may be retrieved from a controller, where the driving route information includes learned driving route information. The learned driving route may be matched to the current driving route based on a plurality of variables including vehicle location, time of day, date, day of the week, trajectory, and/or driver status. The identity of the driver may be entered by the driver or may be inferred based on driving habits, seat position, cab climate control preferences, voice activated commands, and the like. In another example, a vehicle driver or customer (in the case of a car sharing program) may enter one or more destinations into an in-vehicle navigation system (e.g., GPS) or software application, such that accessing driving route information at 1715 may include: driving route information input by a driver of the vehicle is accessed. In some examples, accessing driving route information may include: a lookup table, such as lookup table 420 depicted above at fig. 4B, is accessed in response to a particular driving route being identified with a high probability as the current driving route.

Proceeding to 1720, method 1700 may include: indicating whether any segment of the current driving cycle contains an altitude change (in this example, a descending altitude or downhill segment) in which the pressure change generation may be greater than a predetermined pressure change generation threshold of the sealed fuel system. For example, the pressure change production threshold may include vacuum formation of-8 InH2O or higher (e.g., more negative than-8 InH 2O). Such examples are intended to be illustrative, and it will be appreciated that the pressure change generating amount may include a vacuum build-up sufficient to enable effective passive purging of the canister in response to unsealing the fuel system at a negative pressure relative to atmospheric pressure.

The amount of vacuum expected to be created in the fuel system for a particular change in altitude may vary depending on the fuel level in the fuel tank. In particular, for a given change in altitude, a greater vacuum (e.g., more negative relative to atmospheric pressure) may be expected when the fuel level is higher than when the fuel level is lower. Thus, a look-up table may be stored at the controller, the look-up table including vacuum levels expected to develop in the fuel system as a function of altitude change and fuel level.

Retrieving information at 1720 may further include: information relating to the loading state of the fuel vapor storage canister is retrieved. For example, the canister may be loaded to any varying amount depending on past driving cycles, refueling events, purging events, and the like. Thus, at 1720, the controller can retrieve information related to the degree of canister loading.

Still further, retrieving information at 1720 may include: indicating whether any tests for the presence or absence of undesirable evaporative emissions have been scheduled for any of the identified downhill sections. In other words, at 1720, method 1700 may retrieve from the controller any information related to the method of fig. 5, which may include any scheduled tests for the presence or absence of undesirable evaporative emissions.

Further still, retrieving information about the downhill segment of the current driving cycle may include: indicating which of the identified downhill sections include sections of the driving cycle immediately following the downhill section where the vehicle is expected to climb quickly in height or where the vehicle is expected to perform driving maneuvers that may cause fuel sloshing in the fuel tank. As discussed above, such a section immediately following a downhill section may make it undesirable to test for undesirable evaporative emissions for such a downhill section, as the pressure bleed-off rise portion of the test for undesirable evaporative emissions may be adversely affected by any fuel system pressure variation not related to the bleed-off rise. For example, one or more fuel slosh events may contribute to a pressure bleed-off ramp portion of an undesirable evaporative emissions test, which may result in a false fault being indicated for a particular test. A similar result may occur if the downhill section is followed by an increase in altitude.

While such a situation is undesirable for conducting tests for undesirable evaporative emissions, such a situation may still allow for passive cleaning operations. In particular, at the end of a particular downhill segment, the fuel system may be de-energized and the canister may be quickly and passively purged when fuel system pressure is quickly relieved before the vehicle travels through a segment where fuel sloshing or an increase in altitude, for example, is expected.

Proceeding to 1725, method 1700 may include: the passive purge is scheduled for the current driving cycle. As discussed, passive purging may not be scheduled for any downhill segment for which testing for undesirable evaporative emissions has been scheduled, but it will be appreciated that such testing may inherently include passive purging provided that the fuel system and evaporative emissions system are free of undesirable evaporative emissions.

In some examples, a passive purge event may be scheduled for one or more downhill segments for which there is a segment immediately following the downhill segment that may cause pressure changes in the fuel system that may adversely affect the interpretation of the pressure bleed-off rise test, but which may not adversely affect passive purge due to the rapid nature of the pressure relief in the fuel system in response to unsealing the fuel system.

Depending on the loading state and fuel level of the canister, one or more passive purge events may be scheduled for a particular driving cycle. For example, the greater the loading state of the canister, the more passive wash events may be scheduled, provided that it is inferred that the current driving cycle includes one or more downhill segments sufficient for effective passive wash operation.

In some examples, the controller may take into account the expected vacuum build-up for each particular downhill segment identified, which varies as a function of the time and distance traveled downhill and the fuel level in the fuel tank. The fuel level may include a predicted fuel level at a particular downhill segment, which may be predicted based on an estimated miles traveled before reaching the particular downhill segment. From the knowledge/estimation of vacuum buildup for each particular segment, it can be ascertained as to the extent to which desorption of fuel vapors from the canister via passive purging is expected for each particular downhill segment identified. Such information may be used to schedule a passive wash operation. For example, if it is indicated that a single passive washing operation corresponding to a particular downhill section will be sufficient to effectively clean a canister, such downhill section may be selected for passive washing operation while other sections may be excluded. In another example, based on similar knowledge of the amount of clean canisters expected for each particular downhill segment identified, more than one passive purging operation may be scheduled such that, in combination, the canisters may be effectively passively purged during the driving cycle. In some examples, if the indication of a passive purge operation is sufficient to reduce canister loading conditions below a canister threshold loading level, then only passive purge operations may be necessary for a particular driving cycle and active purge events may be avoided.

In response to scheduling one or more passive purge operations at 1725, method 1700 may proceed to 1730. At 1730, method 1700 may include: the passive purge operation is performed according to fig. 18 in response to the condition for performing the passive purge operation being satisfied.

Accordingly, advancing to FIG. 18 illustrates an exemplary method 1800 for a passive wash operation based on knowledge of a downhill segment of a particular driving cycle. The method 1800 may be stored as executable instructions in a non-transitory memory at a controller. The instructions for implementing method 1800 and the remaining methods included herein may be executed by the controller based on instructions stored on a memory of the controller in conjunction with signals received from sensors of the engine system, such as the sensors described above with reference to fig. 1-2. The controller may employ a fuel system and evaporative emissions system actuator, a Canister Vent Valve (CVV) (e.g., 297), a Canister Purge Valve (CPV) (e.g., 261), etc. according to the methods depicted below. In examples that include a Fuel Tank Isolation Valve (FTIV) (e.g., 252) in the vehicle, the controller may control the FTIV, as discussed above.

Method 1800 may begin at 1805 and may include: indicating whether the conditions for performing the passive purge operation scheduled via method 1700 are satisfied. Satisfying the conditions for performing the passive washing may include: an indication that the vehicle is located within a threshold distance (e.g., 30 feet or less) and/or a threshold duration (e.g., 10 seconds or less) of a downhill segment that is predicted to be sufficient to create at least a predetermined vacuum (e.g., negative pressure relative to atmospheric pressure) for effective passive cleaning of the canister. The predetermined vacuum may include, for example, -8InH2O, but may be greater or smaller in some examples. Additionally or alternatively, satisfying the condition at 1805 may include: an indication of a request to passively clean the canister. Additionally or alternatively, satisfying the condition at 1805 may include: an indication of canister load above a threshold canister load. Additionally or alternatively, satisfying the condition at 1805 may include: the indication of the test for the presence or absence of undesirable evaporative emissions, which relies on the reduced altitude of the vehicle, is not scheduled for a particular downhill segment.

In response to not indicating at 1805 that the condition is satisfied, method 1800 may proceed to 1810, where the current vehicle operating parameters may be maintained. For example, if the engine is in operation to propel the vehicle, such operation may be maintained. Such operation may be maintained if the motor is operating to propel the vehicle. Where some combination of the motor and engine are operating to propel the vehicle, then such operation may be maintained. The current state of the CPV, FTIV and CVV may be maintained. Method 1800 may then end.

Returning to 1805, in response to an indication that the conditions for performing the passive purge operation are satisfied, method 1800 may proceed to 1815. At 1815, method 1800 may include: the fuel system is sealed. It will be appreciated that for vehicles having a sealed fuel tank, where the fuel tank is sealed via an FTIV, then there may be a standing pressure in the fuel system. Thus, if there is a positive pressure in the fuel system relative to atmospheric pressure, the fuel system may be vented just prior to the vehicle lowering the altitude in order to reduce the pressure in the fuel system to atmospheric pressure before resealing the fuel system. The fuel system may be resealed via commanding the FTIV to close, with the FTIV commanded to open to reduce the fuel system pressure to atmospheric pressure. As an alternative option, where FTIV closure is commanded, the fuel system may be sealed via commanding CVV closure. It is appreciated that where the vehicle does not include an FTIV, the CVV may be commanded closed at 1815 to seal the fuel system from the atmosphere.

Proceeding to 1820, in response to sealing the fuel system, method 1800 may include: fuel system pressure is monitored as the vehicle lowers altitude. Pressure may be monitored via, for example, an FTPT (e.g., 291). Continuing to 1825, the method 1800 may include: indicating whether a passive purge pressure threshold has been reached. The passive purge pressure threshold may include a negative pressure relative to atmospheric pressure, and may include a maximum amount of negative pressure build-up (e.g., -16InH2O) desired by the fuel system during the vehicle's reduced altitude. As discussed above (see step 1720 of method 1700), it can be appreciated that a vehicle reduction that results in a vacuum buildup that is less negative (e.g., -8InH2O) than the passive purge pressure threshold may be used to perform the passive purge operation, but the passive purge pressure threshold is set to the maximum amount of pressure that is allowed to build up in the fuel system during the period of reduced altitude prior to initiating the passive purge operation.

Thus, at 1825, if the passive wash threshold has not been indicated to have been reached, the method 1800 may proceed to 1830, where an indication is made as to whether the end of the hill section has been reached. The end of a hill section may be indicated via GPS and/or in response to pressure stabilization in the fuel system (e.g., no more than 5% change over a predetermined period of time, such as 10 seconds, 20 seconds, etc.). In other words, the end of hill lowering includes the vehicle having lowered its altitude along the entire hill section predicted to be sufficient to create at least a predetermined vacuum for effective passive canister cleaning. In other words, the end of hill lowering may include an indication that the vehicle has been fully lowered along a downhill segment predicted to be sufficient to create at least a predetermined vacuum. If at 1830, it is not indicated that the end of the hill section has been reached, method 1800 may return to 1820, where fuel system pressure continues to be monitored.

At 1825, in response to an indication that the passive purge pressure threshold has been reached, method 1800 may proceed to 1835. At 1835, method 1800 includes: unsealing the fuel system. Where the FTIV is commanded to close to seal the fuel system, then the FTIV may be commanded to open. Where the CVV is commanded to close to seal the fuel system (when the FTIV is open, where the vehicle includes the FTIV), then the CVV may be commanded to open (and the FTIV is maintained open, where the vehicle includes the FTIV).

With the fuel system fluidly coupled to the atmosphere, method 1800 may proceed to 1840. At 1840, the method 1800 may include: the temperature of the canister (e.g., 222) is monitored as the fuel system pressure is relieved to atmospheric pressure. In particular, with the fuel system at negative pressure, atmospheric air may be drawn across the canister and thus fuel vapor may be desorbed from the canister and returned to the fuel tank where the vapor may condense into liquid fuel in response to fluidly coupling the fuel system to the atmosphere. As the fuel vapor is desorbed, the canister temperature may decrease. Thus, by monitoring canister temperature changes during passive purging operations, canister loading status may be determined.

Thus, proceeding to 1845, method 1800 may include: indicating whether the canister loading condition is below a threshold canister load (e.g., less than 5% of full vapor). In other words, at 1845, method 1800 may include: indicating whether the canister is clean. If so, method 1800 may proceed to 1850 and may include: the fuel system is resealed. Step 1850 is depicted as a dashed box, as in the case where the fuel system does not include an FTIV, then the fuel system may remain coupled to atmosphere via the opened CVV. However, where the fuel system includes a sealed fuel system, the FTIV may be commanded closed at 1850 in order to seal the fuel system.

Proceeding to 1855, the method 1800 may include: the vehicle operating parameters are updated. In particular, because the canister is indicated as clean after a partial wash event, there is no reason to continue passively washing the canister even if the hill section endpoint has not been reached. Accordingly, updating the vehicle operating parameters at 1855 may include: the canister loading status is updated at the controller. Updating the vehicle operating parameters at 1855 may additionally include: the canister purge schedule is updated to reflect the indication of canister cleanliness. For example, an active wash event scheduled for the current driving cycle may be cancelled. Any further passive cleaning events may also be eliminated. However, such actions may only be applicable to those vehicles having a sealed fuel tank. For vehicle systems that do not include a sealed fuel system, the running exhaust vapors may continue to load the canister during vehicle operation. In such cases, any scheduled passive and/or active purge operations may be maintained as scheduled. However, because the canister is partially purged, the aggressiveness of any scheduled active purge event for the current driving cycle may be adjusted, as discussed at 1525 of method 1500. For example, for any future scheduled active wash events, a lower initial rate of CPV duty cycle may be commanded for initiating active wash of the canister. Additionally or alternatively, the rate at which the CPV duty cycle is increased during a particular active purge event may be adjusted to a lower rate. It will be appreciated that the lower initial rate and lower ramp rate may be compared to a situation where no partial cleaning has been performed. Method 1800 may then end.

Returning to 1845, in response to the canister load not being below the threshold canister load, the method 1800 may proceed to 1847, where the fuel system may be resealed via commanding an FTIV closure or commanding a CVV closure. Proceeding to 1830, if the end of hill descent has not been indicated, the method 1800 may continue to monitor fuel system pressure at 1820. In other words, another passive purge operation may be performed because the vehicle is still at reduced altitude with the fuel system sealed. Any number of such passive cleaning operations may be performed in this manner depending on the length and steepness of the altitude decrease.

From 1830, where one or more passive purge operations are being performed while the vehicle is at reduced altitude, or where a passive purge pressure threshold is not reached but indicates that the end of a downhill slope has been reached, method 1800 may proceed to 1860.

At 1860, the method 1800 may include: the fuel system is deblocked, as discussed above with respect to step 1835. Proceeding to 1865, the method 1800 may include: canister temperature changes are monitored as the pressure is relieved to atmospheric pressure, as discussed above at step 1840. In this way, canister loading status may be determined. Continuing at 1870, method 1800 may include: the fuel system is resealed (where applicable). As with step 1850, step 1870 is depicted as a dashed box because fuel system unseal may be maintained at 1870 for vehicles without an FTIV. However, for vehicles with sealed fuel tanks, FTIV closure may be commanded at 1870.

Continuing at 1855, method 1800 may include: the vehicle operating parameters are updated. Updating vehicle operating parameters at 1855 may vary according to the canister loading state determined at 1865. For example, if the canister is indicated as clean, then a subsequent active wash event scheduled for the current driving cycle may be cancelled. Similarly, any subsequent passive wash events scheduled for the current driving cycle may be cancelled. However, this action may only be applicable to those vehicles having a sealed fuel system. For vehicles with fuel systems that are not sealed under most vehicle operating conditions, then the running loss vapors during vehicle operation may again load the canister to a significant degree. In such an example, any active or passive wash event scheduled for the current driving cycle may be maintained as scheduled. However, because the canister is passively cleaned, the aggressiveness of any subsequent active cleaning events may be adjusted, as discussed above.

In the event canister cleaning is not indicated, updating the vehicle operating parameters may include: maintaining any scheduled active and/or passive wash events scheduled for the current driving cycle. However, because the canister is partially purged, subsequent scheduled active canister purge events may be performed at the adjusted aggressiveness level. Whether or not the fuel system includes an FTIV, the aggressiveness of any subsequent active purge events may be adjusted. Method 1800 may then end.

Accordingly, a method may comprise: sealing a fuel system of a vehicle and then reducing an altitude change that was predicted before the vehicle reduced the altitude change. After the vehicle reduces the change in altitude, the method may include: unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister to a fuel tank of the vehicle.

In this approach, the elevation changes predicted in advance may occur along a learned driving route learned over time. In some examples, the elevation change predicted in advance may be based on a driving route selected by a driver of the vehicle or selected by a passenger. In some examples, the altitude change predicted in advance may result in a negative pressure being formed in the fuel system relative to atmospheric pressure, the negative pressure being at least a predetermined negative pressure. For example, the predetermined negative pressure may include-8 InH 2O.

In this method, the method may further include: de-activating the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude under conditions that a predetermined passive purge threshold negative pressure is reached in the fuel system during the reducing the change in altitude. Such a method may further comprise: resealing the fuel system in response to a pressure in the fuel system during the reducing the change in altitude being within a threshold of atmospheric pressure. In some examples, the predetermined passive purge threshold negative pressure may include-16 InH 2O. In some examples, such a method may further comprise: unsealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude, and resealing the fuel system in response to the pressure in the fuel system being within the threshold of atmospheric pressure, any number of times during the reducing the change in altitude.

In this method, the method may further include: monitoring pressure in the sealed fuel system after the reducing the change in altitude and prior to unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister; and indicating the absence of undesirable evaporative emissions from the fuel system in response to the pressure in the sealed fuel system remaining below a pressure bleed-off rise threshold for a predetermined duration.

In this method, the method may further include: monitoring a temperature change of the fuel vapor storage canister during the passive purging of the fuel vapor to the fuel tank; and indicating a loading state of the fuel vapor storage canister based on the temperature change.

Another example of a method may include: passively purging a fuel vapor storage canister of a vehicle during a driving cycle, the fuel vapor storage canister capturing and storing fuel vapor from a fuel system via sealing the fuel system for a duration of a predicted decrease in altitude of travel of the vehicle; the fuel system is then de-activated after the known altitude is reduced to direct fuel vapor from the fuel vapor storage canister to a fuel tank of the fuel system. Such a method may further comprise: adjusting the aggressiveness of a subsequent active purge of the fuel vapor storage canister based on the passive purge.

In such a method, the predicted elevation reduction may include a learned elevation change or may be inferred from the selected route.

In such a method, the active purge may include a purge event of the fuel vapor storage canister that is dependent on the vacuum communicated to the fuel vapor storage canister from an engine of the vehicle. In such an example, adjusting the aggressiveness of the active purge may comprise: reducing a canister purge valve cycle duty positioned in a purge line coupling the fuel vapor storage canister to the engine for an initial rate of performing the active purge as compared to a case in which the aggressiveness of the active purge is not adjusted. In some examples, adjusting the aggressiveness of the active purge may further comprise: adjusting a ramp rate at which a duty cycle of the purge valve increases during the active purge.

In this method, the method may further include: monitoring a change in temperature of the fuel vapor storage canister during the passive purging of the fuel vapor storage canister to indicate a duty cycle of a purge valve a loading state of the fuel vapor storage canister. In such an example, adjusting the aggressiveness of the active purge may comprise: canceling the active purge in response to an indication that the loading status of the fuel vapor storage canister is below a canister load threshold.

Advancing to FIG. 19 shows an exemplary timeline 1900 for performing a passive purge operation based on vacuum build-up in the fuel system in response to the vehicle lowering the altitude. The time line 1900 includes a curve 1905 that indicates whether the engine is started (combusting air and fuel) or shut down over time. The timeline 1900 also includes a curve 1910 indicating whether conditions are met for performing a passive purge operation that depends on vacuum formation in the fuel system during a decrease in vehicle altitude. The timeline 1900 also includes a curve 1915 that indicates whether the end of a hill section where the vehicle is traveling to reduce altitude is reached over time. The timeline 1900 also includes: a curve 1920 indicating whether the CPV is open or closed over time; and a curve 1925 indicating whether the FTIV is open or closed over time. The timeline 1900 also includes a curve 1930 indicating pressure in the fuel system as monitored over time, e.g., via an FTPT (e.g., 291). In this exemplary timeline, the pressure in the fuel system is near atmospheric pressure (Atm.), or negative (-) relative to atmospheric pressure. The timeline 1900 also includes a curve 1935 indicating canister loading status over time. The canister loading state may rise (+) or fall (-) over time. The timeline 1900 also includes a curve 1940 that indicates whether the aggressiveness of the active wash operation has been adjusted (yes) or has not been adjusted (no) over time. The timeline 1900 also includes a curve 1945 that indicates whether the CVV is open or closed over time.

At time t0, the engine is off. Although not explicitly shown, it is understood that the vehicle is in operation and is propelled via a motor (e.g., 120). The conditions for performing the passive purge operation have not been met (curve 1910), and therefore the vehicle has not traveled through any hill section for which a passive purge operation is scheduled (curve 1915). CPV is closed (curve 1920) and FTIV is closed (curve 1925). The pressure in the fuel system is at atmospheric pressure (curve 1930) and the canister is nearly saturated with fuel vapor (curve 1935). Since a passive wash event has not yet occurred, the aggressiveness of any active wash event has not been adjusted (curve 1940). Further, the CVV is open (curve 1945).

At time t1, it is indicated that the condition for performing the passive washing operation is satisfied. In particular, the vehicle is within a threshold distance of a downhill grade for which a passive wash operation is scheduled (e.g., within 30 feet or less), and because the canister load is high, a passive wash operation is desired. Because the fuel system is near atmospheric pressure, no further operation is performed at time t 1. However, where the fuel system pressure is positive relative to atmospheric pressure, it will be appreciated that the fuel system may first be vented to bring the pressure in the fuel system to atmospheric pressure before sealing the fuel system. In this exemplary timeline, where the pressure in the fuel system is at atmospheric pressure, the FTIV is maintained closed so that the fuel system maintains a seal.

Between times t1 and t2, as the vehicle decreases in altitude, the pressure in the fuel system decreases. At time t2, a passive purge pressure threshold (e.g., -16InH2O) is reached (represented by line 1931). Thus, at time t2, the FTIV is commanded to open (curve 1925) and the CVV is maintained open (curve 1945). With the FTIV open, the fuel system is fluidly coupled to atmosphere and, therefore, between times t2 and t3, the pressure in the fuel system quickly returns to atmospheric pressure (curve 1930). As atmospheric air is drawn across the canister, the pressure in the fuel system returns to atmospheric pressure, thereby venting fuel vapor from the canister to the fuel tank. Thus, between times t2 and t3, the canister load drops. As discussed above, the canister loading state may be indicated based on temperature changes at the canister during passive purging operations. However, between times t2 and t3, the canister loading state does not drop to or below the threshold canister load (represented by line 1936). In other words, between times t2 and t3, the fuel vapor in the canister is not cleaned (e.g., loaded to less than 5%).

Because the canister is still loaded to a significant amount (curve 1935), and because the end of the hill section has not been reached (curve 1915), at time t3, the FTIV is commanded to close (curve 1925), sealing the fuel system. Therefore, between times t3 and t4, negative pressure is again created in the sealed fuel system (curve 1930). However, between times t3 and t4, the negative pressure does not reach the passive purge pressure threshold (line 1936). Alternatively, at time t4, it is indicated that the end of the hill section has been reached (curve 1915). Such an indication may be provided, for example, via an in-vehicle navigation system (e.g., GPS).

Having reached the end of the hill section at time t4, the FTIV is commanded to open (curve 1925) fluidly coupling the fuel system to the atmosphere. Between times t4 and t5, the canister loading state drops as the fuel system pressure is relieved to atmospheric pressure (curve 1930). However, again, the canister loading state does not drop to the canister load threshold (line 1936). In other words, the canister is still loaded to some extent.

At time t5, with the pressure in the fuel system at atmospheric pressure, the FTIV is commanded to close (curve 1925). In the case where the end point of the hill section has been reached, and in the case where the passive washing operation has been performed, it is no longer indicated that the condition for performing the passive washing is satisfied (curve 1910). However, since the canister load has not decreased below the canister load threshold (represented by line 1936), but since the canister load has decreased significantly by performing a passive purge operation, at time t6, the controller adjusts the aggressiveness of any subsequent active purge operations scheduled for the current driving cycle. In particular, as discussed above, the initial CPV duty cycle rate of the active purge operation may be reduced as compared to a case where one or more partial purge operations are not performed for the current driving cycle. Additionally or alternatively, the rate at which the CPV duty cycle is increased or ramped up during active wash operation may be reduced compared to when one or more partial wash operations have not been performed in the current driving cycle.

In some examples, the adjusted initial rate and/or the adjusted ramp rate of the CPV duty cycle may be adjusted according to canister loading conditions. For example, depending on the amount of a particular canister load reduction, and depending on the level of loading remaining in the canister after one or more partial wash operations have been performed, the initial rate of CPV duty cycle and/or the ramp rate may be adjusted accordingly. In particular, the more a particular canister load is reduced and the lower the level of loading remaining in the canister after one or more partial wash operations, the lower the adjusted initial rate and/or the adjusted ramp rate of the CPV duty cycle may be for an active wash event. This determination of aggressiveness for active cleaning events may be determined via the controller.

In this manner, canister load may be reduced during a driving procedure without relying on engine manifold vacuum, which may be particularly desirable for hybrid electric vehicles and/or other vehicles designed to operate with a reduced amount of engine manifold vacuum. By reducing canister loading via a method that is not dependent on engine manifold vacuum, blowdown emissions from the canister that might otherwise occur may be reduced or avoided. Further, reducing blowdown emissions by passively purging stored fuel vapor back to the fuel tank may improve fuel economy.

The technical effect is to realize that: a common driving program for a particular vehicle driver may be learned via a controller of the vehicle such that it may be determined with a high degree of confidence whether the learned driving program may include downhill sections sufficient to allow for passive washing operations. Another technical effect is the recognition that: this ability to determine whether a particular driving cycle includes such downhill segments for passive cleaning may be accomplished via a vehicle navigation system that a vehicle driver or passenger may use to enter or select a particular driving route. Yet another technical effect is the recognition that: in the case where one or more passive washing operations are scheduled and performed for a specific driving cycle, the aggressiveness of active washing scheduled after the passive washing operations have been performed can be reduced. By reducing the active purge aggressiveness, conditions such as engine surge and/or engine stall may be reduced or avoided. Yet another technical effect is the recognition that: in some examples, the partial purging of the fuel vapor canister may be performed via a process of conducting a test for the presence or absence of undesirable evaporative emissions, where such a test also relies on the creation of a vacuum in the fuel system as vehicle altitude decreases over time.

One or more systems and one or more methods may be implemented with the systems described herein and with reference to fig. 1-2, and the methods described herein and with reference to fig. 3, 5-6, 8-9, 11-12, 14, and 15-18. In one example, a method comprises: sealing a fuel system of a vehicle and then reducing an altitude change, the altitude change being predicted before the vehicle reduces the altitude change; and after the vehicle reduces the change in altitude, unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister to a fuel tank of the vehicle. In a first example of the method, the method may further comprise: wherein the elevation change predicted in advance occurs along a learned driving route learned over time. A second example of the method optionally includes the first example, and further comprising: wherein the elevation change predicted in advance is based on a driving route selected by a driver of the vehicle or selected by a passenger. A third example of the method optionally includes any one or more or each of the first to second examples, and further comprising: wherein the altitude change predicted in advance causes a negative pressure to be formed in the fuel system with respect to atmospheric pressure, the negative pressure being at least a predetermined negative pressure. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further comprising: wherein the predetermined negative pressure is-8 InH 2O. A fifth example of the method optionally includes any one or more or each of the first to fourth examples, and further comprising: de-activating the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude under conditions in the fuel system that reach a predetermined passive purge threshold negative pressure during the reducing the change in altitude; and resealing the fuel system in response to a pressure in the fuel system being within a threshold of atmospheric pressure during the reducing the change in altitude. A sixth example of the method optionally includes any one or more or each of the first to fifth examples, and further comprising: wherein the predetermined passive purge threshold negative pressure is-16 InH 2O. A seventh example of the method optionally includes any one or more or each of the first to sixth examples, and further comprising: wherein unsealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude, and resealing the fuel system in response to the pressure in the fuel system being within the threshold of atmospheric pressure, occurs any number of times during the reducing the change in altitude. An eighth example of the method optionally includes any one or more or each of the first to seventh examples, and further comprising: monitoring pressure in the sealed fuel system after the lowering of the altitude and prior to unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister; and indicating the absence of undesirable evaporative emissions from the fuel system in response to the pressure in the sealed fuel system remaining below a pressure bleed-off rise threshold for a predetermined duration. A ninth example of the method optionally includes any one or more or each of the first to eighth examples, and further comprising: monitoring a temperature change of the fuel vapor storage canister during the passive purging of the fuel vapor to the fuel tank; and indicating a loading state of the fuel vapor storage canister based on the temperature change.

Another example of a method includes: passively purging a fuel vapor storage canister of a vehicle during a driving cycle, the fuel vapor storage canister capturing and storing fuel vapor from a fuel system via sealing the fuel system for a duration of a predicted decrease in altitude of travel of the vehicle; then after the known altitude is reduced, unsealing the fuel system to direct fuel vapor from the fuel vapor storage canister to a fuel tank of the fuel system; and adjusting the aggressiveness of a subsequent active purge of the fuel vapor storage canister based on the passive purge. In a first example of the method, the method comprises: wherein the predicted elevation reduction comprises a learned elevation change or is inferred from the selected route. A second example of the method optionally includes the first example, and further comprising: wherein the active purge comprises a purge event of the fuel vapor storage canister that is dependent on a vacuum communicated from an engine of the vehicle to the fuel vapor storage canister; and wherein adjusting the aggressiveness of the active purge comprises: reducing an initial rate at which canister purge valve cycles located in a purge line coupling the fuel vapor storage canister to the engine for performing the active purge compared to without adjusting the aggressiveness of the active purge. A third example of the method optionally includes any one or more or each of the first example and the second example, and further comprising: wherein adjusting the aggressiveness of the active purge further comprises: adjusting the ramp rate at which the duty cycle of the purge valve increases during the active purge. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further comprising: monitoring a change in temperature of the fuel vapor storage canister during the passive purging of the fuel vapor storage canister to indicate a loading status of the fuel vapor storage canister; and wherein adjusting the aggressiveness of the active purge comprises: canceling the active purge in response to an indication that the loading status of the fuel vapor storage canister is below a canister load threshold.

An example of a system for a vehicle includes: a fuel system including a fuel tank selectively fluidly coupled to a fuel vapor storage canister via a fuel tank isolation valve, the fuel vapor storage canister positioned in an evaporative emissions system, and wherein the fuel vapor storage canister is selectively fluidly coupled to atmosphere via a canister vent valve and selectively coupled to an intake port of an engine via a canister purge valve; a vehicle-mounted navigation system; and a controller having computer readable instructions stored on a non-transitory memory that, when executed, cause the controller to: in response to an indication that the vehicle is within a threshold distance of a decrease in altitude predicted to result in at least a predetermined level of vacuum being formed in the fuel system and evaporative emissions as indicated via the on-board navigation system, coupling the fuel system to the evaporative emissions system via commanding the fuel tank isolation valve to open and then sealing the fuel system and the evaporative emissions system via commanding the canister vent valve to close; maintaining a target vacuum in the fuel system and the evaporative emissions system via cycling the canister vent valve during the altitude decrease; conducting a test for the presence or absence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system via monitoring a pressure bleed-off rise in the fuel system and the evaporative emissions system sealed from the atmosphere just after the altitude decrease; responsive to a determination of the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, unsealing the fuel system and the evaporative emissions system; and adjusting the aggressiveness of subsequent active purge operations of the fuel vapor storage canister based on the indication of the presence or absence of the undesired evaporative emissions. In a first example of such a system, the system may further comprise: wherein the controller stores further instructions for indicating the presence of an undesired evaporative emission from the fuel system and/or the evaporative emission system in response to the pressure bleed rising above a predetermined pressure bleed rising threshold and/or in response to the pressure bleed rising rate exceeding a predetermined pressure bleed rising rate, for a predetermined duration. A second example of such a system optionally includes the first example, and further comprising: wherein the controller stores further instructions for actively purging the canister during a subsequent active purge operation via commanding the canister vent valve to open and cycling the canister purge valve to apply intake manifold vacuum to the fuel vapor storage canister to purge fuel vapor stored in the fuel vapor storage canister to the engine for combustion; and wherein adjusting the aggressiveness of the subsequent active purge operations comprises: initiating the subsequent active purge operation at a lower duty cycle of the canister purge valve and reducing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the indication of the absence of the undesired evaporative emissions as compared to initiating the subsequent active purge operation at a higher duty cycle of the canister purge valve and increasing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the presence of the undesired evaporative emissions. A third example of the system optionally includes any one or more or each of the first to second examples, and further includes a temperature sensor positioned in the fuel vapor storage canister; and wherein the controller stores further instructions for monitoring a change in temperature of the fuel vapor storage canister to indicate a loading state of the canister in response to: unsealing the fuel system and the evaporative emissions system in response to the determination made as to the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, wherein unsealing the fuel system and the evaporative emissions system passively purges fuel vapor stored in the fuel vapor storage canister back to the fuel tank. A fourth example of the system optionally includes any one or more or each of the first to third examples, and further comprising: wherein the controller stores further instructions for adjusting the aggressiveness of the subsequent active wash operation as a function of the loading state of the canister.

It should be noted that the exemplary control and estimation routines included herein may be used with various engine and/or vehicle system configurations. The control methods and programs disclosed herein may be stored as executable instructions in a non-transitory memory and executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various acts, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases, omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts, operations, and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described acts, operations, and/or functions may graphically represent code to be programmed into the non-transitory memory of the computer readable storage medium in the engine control system, wherein the described acts are implemented by execution of the instructions in combination with an electronic controller in a system comprising various engine hardware components.

It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above techniques may be applied to V6 cylinders, inline 4 cylinders, inline 6 cylinders, V12 cylinders, opposed 4 cylinders, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, such that two or more such elements are neither required nor excluded. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

According to the invention, a method comprises: sealing a fuel system of a vehicle and then reducing an altitude change, the altitude change being predicted before the vehicle reduces the altitude change; and after the vehicle reduces the change in altitude, unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister to a fuel tank of the vehicle.

According to one embodiment, the elevation change predicted in advance occurs along a learned driving route learned over time.

According to one embodiment, the altitude change predicted in advance is based on a driving route selected by a driver of the vehicle or selected by a passenger.

According to one embodiment, the altitude change predicted in advance results in a negative pressure being formed in the fuel system with respect to the atmospheric pressure, the negative pressure being at least a predetermined negative pressure.

According to one embodiment, the predetermined negative pressure is-8 InH 2O.

According to one embodiment, the above invention is further characterized in that: de-activating the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude under conditions in the fuel system that reach a predetermined passive purge threshold negative pressure during the reducing the change in altitude; and resealing the fuel system in response to a pressure in the fuel system being within a threshold of atmospheric pressure during the reducing the change in altitude.

According to one embodiment, the predetermined passive purge threshold negative pressure is-16 InH 2O.

According to one embodiment, unsealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude, and resealing the fuel system in response to the pressure in the fuel system being within the threshold of atmospheric pressure, occurs any number of times during the reducing the change in altitude.

According to one embodiment, the above invention is further characterized in that: after the lowering of the altitude and prior to unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister, monitoring pressure in the sealed fuel system and indicating the absence of undesirable evaporative emissions from the fuel system in response to the pressure in the sealed fuel system remaining below a pressure bleed-off rise threshold for a predetermined duration.

According to one embodiment, the above invention is further characterized in that: monitoring a temperature change of the fuel vapor storage canister during the passive purging of the fuel vapor to the fuel tank; and indicating a loading state of the fuel vapor storage canister based on the temperature change.

According to the invention, a method comprises: passively purging a fuel vapor storage canister of a vehicle during a driving cycle, the fuel vapor storage canister capturing and storing fuel vapor from a fuel system via sealing the fuel system for a duration of a predicted decrease in altitude of travel of the vehicle; then after the known altitude is reduced, unsealing the fuel system to direct fuel vapor from the fuel vapor storage canister to a fuel tank of the fuel system; and adjusting the aggressiveness of a subsequent active purge of the fuel vapor storage canister based on the passive purge.

According to one embodiment, the predicted elevation reduction comprises a learned elevation change or is inferred from the selected route.

According to one embodiment, the active purge comprises a purge event of the fuel vapor storage canister, the purge event being dependent on a vacuum communicated from an engine of the vehicle to the fuel vapor storage canister; and wherein adjusting the aggressiveness of the active purge comprises: reducing an initial rate at which canister purge valve cycles located in a purge line coupling the fuel vapor storage canister to the engine for performing the active purge compared to without adjusting the aggressiveness of the active purge.

According to one embodiment, adjusting the aggressiveness of the active purge further comprises: adjusting the ramp rate at which the duty cycle of the purge valve increases during the active purge.

According to one embodiment, the above invention is further characterized in that: monitoring a change in temperature of the fuel vapor storage canister during the passive purging of the fuel vapor storage canister to indicate a loading status of the fuel vapor storage canister; and wherein adjusting the aggressiveness of the active purge comprises: canceling the active purge in response to an indication that the loading status of the fuel vapor storage canister is below a canister load threshold.

According to the invention, a system for a vehicle is provided, having: a fuel system including a fuel tank selectively fluidly coupled to a fuel vapor storage canister via a fuel tank isolation valve, the fuel vapor storage canister positioned in an evaporative emissions system, and wherein the fuel vapor storage canister is selectively fluidly coupled to atmosphere via a canister vent valve and selectively coupled to an intake port of an engine via a canister purge valve; a vehicle-mounted navigation system; and a controller having computer readable instructions stored on a non-transitory memory that, when executed, cause the controller to: in response to an indication that the vehicle is within a threshold distance of a decrease in altitude predicted to result in at least a predetermined level of vacuum being formed in the fuel system and evaporative emissions as indicated via the on-board navigation system, coupling the fuel system to the evaporative emissions system via commanding the fuel tank isolation valve to open and then sealing the fuel system and the evaporative emissions system via commanding the canister vent valve to close; maintaining a target vacuum in the fuel system and the evaporative emissions system via cycling the canister vent valve during the altitude decrease; conducting a test for the presence or absence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system via monitoring a pressure bleed-off rise in the fuel system and the evaporative emissions system sealed from the atmosphere just after the altitude decrease; responsive to a determination of the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, unsealing the fuel system and the evaporative emissions system; and adjusting the aggressiveness of subsequent active purge operations of the fuel vapor storage canister based on the indication of the presence or absence of the undesired evaporative emissions.

According to one embodiment, the controller stores further instructions for indicating the presence of an undesired evaporative emission from the fuel system and/or the evaporative emission system in response to the pressure bleed rising above a predetermined pressure bleed rising threshold and/or in response to the pressure bleed rising rate exceeding a predetermined pressure bleed rising rate for a predetermined duration.

According to one embodiment, the controller stores further instructions for actively purging the canister in a subsequent active purge operation via commanding the canister vent valve to open and cycling the canister purge valve to duty cycle for applying intake manifold vacuum to the fuel vapor storage canister to purge fuel vapor stored in the fuel vapor storage canister to the engine for combustion; and wherein adjusting the aggressiveness of the subsequent active purge operations comprises: initiating the subsequent active purge operation at a lower duty cycle of the canister purge valve and reducing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the indication of the absence of the undesired evaporative emissions as compared to initiating the subsequent active purge operation at a higher duty cycle of the canister purge valve and increasing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the presence of the undesired evaporative emissions.

According to one embodiment, the above invention is further characterized in that: a temperature sensor positioned in the fuel vapor storage canister; and wherein the controller stores further instructions for monitoring a change in temperature of the fuel vapor storage canister to indicate a loading state of the canister in response to: unsealing the fuel system and the evaporative emissions system in response to the determination made as to the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, wherein unsealing the fuel system and the evaporative emissions system passively purges fuel vapor stored in the fuel vapor storage canister back to the fuel tank.

According to one embodiment, the controller stores further instructions for adjusting the aggressiveness of the subsequent active wash operation as a function of the loading state of the canister.

Claims

1. A method, comprising:

sealing a fuel system of a vehicle and then reducing an altitude change, the altitude change being predicted before the vehicle reduces the altitude change; and

after the vehicle reduces the change in altitude, unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister to a fuel tank of the vehicle.

2. The method of claim 1, wherein the elevation change predicted ahead of time occurs along a learned driving route learned over time.

3. The method of claim 1, wherein the elevation change predicted in advance is based on a driving route selected by a driver of the vehicle or selected by a passenger.

4. The method of claim 1, wherein the altitude change predicted in advance results in a negative pressure being created in the fuel system relative to atmospheric pressure, the negative pressure being at least a predetermined negative pressure.

5. The method of claim 4 wherein the predetermined negative pressure is-8 InH 2O.

6. The method of claim 1, further comprising:

de-activating the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude under conditions in the fuel system that reach a predetermined passive purge threshold negative pressure during the reducing the change in altitude; and

resealing the fuel system in response to a pressure in the fuel system being within a threshold of atmospheric pressure during the reducing the change in altitude.

7. The method of claim 6, wherein the predetermined passive purge threshold negative pressure is-16 InH 2O.

8. The method of claim 6, wherein unsealing the fuel system to passively purge fuel vapor stored in the fuel vapor storage canister to the fuel tank while the vehicle is reducing the change in altitude, and resealing the fuel system in response to the pressure in the fuel system being within the threshold of atmospheric pressure, occurs any number of times during the reducing the change in altitude.

9. The method of claim 1, further comprising:

after the lowering of the altitude and prior to unsealing the fuel system to passively purge fuel vapor stored in a fuel vapor storage canister, monitoring pressure in the sealed fuel system and indicating the absence of undesirable evaporative emissions from the fuel system in response to the pressure in the sealed fuel system remaining below a pressure bleed-off rise threshold for a predetermined duration.

10. The method of claim 1, further comprising:

monitoring a temperature change of the fuel vapor storage canister during the passive purging of the fuel vapor to the fuel tank; and

indicating a loading state of the fuel vapor storage canister based on the temperature change.

11. A system for a vehicle, comprising:

a fuel system comprising a fuel tank selectively fluidly coupled to a fuel vapor storage canister positioned in an evaporative emissions system via a fuel tank isolation valve, and wherein the fuel vapor storage canister is selectively fluidly coupled to atmosphere via a canister vent valve and selectively coupled to an intake port of an engine via a canister purge valve;

a vehicle-mounted navigation system; and

a controller having computer-readable instructions stored on a non-transitory memory that, when executed, cause the controller to:

in response to an indication that the vehicle is within a threshold distance of an altitude decrease predicted to result in at least a predetermined vacuum level being formed in the fuel system and evaporative emissions as indicated via the on-board navigation system, coupling the fuel system to the evaporative emissions system via commanding the fuel tank isolation valve to open and then sealing the fuel system and the evaporative emissions system via commanding the canister vent valve to close;

maintaining a target vacuum in the fuel system and the evaporative emissions system via cycling the canister vent valve during the altitude decrease;

conducting a test for the presence or absence of undesirable evaporative emissions from the fuel system and/or the evaporative emissions system via monitoring a pressure bleed-off rise in the fuel system and the evaporative emissions system sealed from the atmosphere just after the altitude decrease;

responsive to a determination of the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, unsealing the fuel system and the evaporative emissions system; and is

Based on the indication of the presence or absence of the undesired evaporative emissions, adjusting the aggressiveness of a subsequent active purge operation of the fuel vapor storage canister.

12. The system of claim 11, wherein the controller stores further instructions for indicating the presence of an undesirable evaporative emission from the fuel system and/or the evaporative emission system in response to the pressure bleed rising above a predetermined pressure bleed rising threshold and/or in response to a pressure bleed rising rate exceeding a predetermined pressure bleed rising rate for a predetermined duration.

13. The system of claim 11, wherein the controller stores further instructions for actively purging the canister during a subsequent active purge operation via commanding the canister vent valve to open and cycling the canister purge valve to duty cycle for applying intake manifold vacuum to the fuel vapor storage canister to purge fuel vapor stored in the fuel vapor storage canister to the engine for combustion; and is

Wherein adjusting the aggressiveness of the subsequent active purge operations comprises: initiating the subsequent active purge operation at a lower duty cycle of the canister purge valve and reducing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the indication of the absence of the undesired evaporative emissions as compared to initiating the subsequent active purge operation at a higher duty cycle of the canister purge valve and increasing a rate at which the duty cycle of the canister purge valve increases during the subsequent active purge operation in response to the presence of the undesired evaporative emissions.

14. The system of claim 11, further comprising a temperature sensor positioned in the fuel vapor storage canister; and is

Wherein the controller stores further instructions for monitoring a change in temperature of the fuel vapor storage canister to indicate a loading state of the canister in response to: unsealing the fuel system and the evaporative emissions system in response to the determination of the presence or absence of undesirable evaporative emissions originating from the fuel system and/or the evaporative emissions system, wherein unsealing the fuel system and the evaporative emissions system passively purges fuel vapors stored in the fuel vapor storage canister back to the fuel tank.

15. The system of claim 14, wherein the controller stores further instructions for adjusting the aggressiveness of the subsequent active wash operation as a function of the loading state of the canister.