DE102009020292B4 - Engine start control for an engine with hydrocarbon retention system - Google Patents

Abstract

A method of operating an engine (10) having an inlet (23), an outlet (25) and a hydrocarbon retention system (22), the engine (10) combusting fuel, the method comprising: during engine starting: selectively routing exhaust gases of the engine Engine to the hydrocarbon retention system (22) for storing hydrocarbons of the exhaust gas and operating with spark advance near a peak torque control time; and selectively purging stored hydrocarbons from the hydrocarbon retention system (22) to the engine inlet (23).

Description

area

The present description relates generally to an exhaust treatment system for an internal combustion engine.

Background / Summary

Engines may use various adjustments during cold start operation to rapidly increase the temperature of a catalytic exhaust gas emission control device. Specifically, retarded ignition may be used to increase the exhaust gas temperature, thereby providing the device with a light-off temperature in a shorter duration, thereby reducing cold-start emissions. As another example, the combustion combustion air-fuel ratio may be easily made lean to further increase exhaust gas temperature and reduce exhaust gas hydrocarbon emissions.

However, the present inventors have recognized various problems with such adjustments. For example, excessive spark ignition may increase the susceptibility to low temperature combustion instability or to different fuel qualities. Similarly, lean setting under cold start conditions can result in misfire and combustion instability of the engine.

From the Scriptures DE 10 2007 006 173 A1 there is known an internal combustion engine to which is coupled a fuel vapor storage system which stores and releases fuel vapors. In this case, exhaust gas is passed from the engine to the steam storage system, wherein absorbed vapors are released into the exhaust gas before the exhaust gas is introduced back into the engine for burning. By the use of exhaust gases for purging the activated carbon filter used as a vapor storage of the cooling can be prevented, as normally occurs in a purge with fresh air.

The font US Pat. No. 3,699,683 A. describes an internal combustion engine in which, during the start-up phase or with a cold engine, the emission of hydrocarbons to the environment is to be prevented by the exhaust gases are passed through an absorber bed that absorbs hydrocarbons. Once the engine has warmed up, the greater part of the exhaust gases are routed past the absorber bed and only a smaller portion of the exhaust gases are used to rinse the absorber bed.

Furthermore, the font shows US 6,334,431 B an internal combustion engine, in which the adjustment of the ignition timing is controlled according to the detected coolant temperature in the morning. In this case, under cold start conditions, the ignition timing is adjusted further to early than would be set for the achievement of the maximum torque, that is, there is a position to early beyond the ignition for maximum torque addition. This aims to inject an increased amount of fuel to compensate for torque loss, thereby increasing the engine operating temperature more rapidly.

The present invention has for its object to mitigate the aforementioned problems. According to the invention this object is achieved by the method according to claims 1, 7 and 15. Preferred embodiments of the invention are the subject of the dependent claims.

Thus, in one approach, there is provided a method of operating an engine having an inlet, an exhaust and a hydrocarbon retention system, the engine combusting fuel, the method comprising: during engine startup: selectively directing the exhaust gases of the engine to the hydrocarbon retention system to store exhaust hydrocarbons and operating with spark advance near a peak torque setting; and selectively purging stored hydrocarbons from the hydrocarbon retention system to the engine intake.

In this way it is possible to reduce the reliance on spark retard, since the hydrocarbon retardant system addresses cold-start emissions. Thus, even assuming that the light-off time for the catalyst increases, the emissions can still be reduced. Thus, it is possible to increase the combustion stability while reducing the exhaust emissions.

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. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims which follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve the disadvantages noted above or in any part of this disclosure.

Brief description of the drawings

1 shows a schematic representation of an engine, an exhaust system and a hydrocarbon (HC) restraint system.

2 shows a schematic representation of an internal combustion engine.

3 . 4 . 5 . 6 and 7 show various embodiments of the HC retention system.

8th . 9 . 10 . 11 . 12 . 13 and 14 show overview flowcharts showing the operation of the engine, the exhaust system and the HC-retention system.

Detailed description

1 shows a schematic representation of a motor vehicle system 6 , The motor vehicle system 6 includes an engine system 8th , which with a hydrocarbon (HC) retention system 22 and a fuel system 18 connected is.

The engine system 8th can a motor 10 with several cylinders 30 include. The motor 10 includes an inlet 23 and an outlet 25 , The inlet 23 includes a throttle 62 , which by means of an inlet channel 44 fluidly with the engine intake manifold 44 connected is. The outlet 25 includes an exhaust manifold 48 which leads to an outlet channel 35 which leads exhaust gas to the atmosphere. The outlet 25 may be one or more emission control devices 70 which may be mounted in a tightly connected position in the outlet. One or more emission control systems may include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, etc. It is understood that other components may be included in the engine, such as a plurality of valves and sensors included in the exemplary engine of FIG 2 are shown.

The outlet 25 Can also be used with the hydrocarbon retention system 22 by means of a line 26 and a valve 24 be actively connected. In one example, exhaust gases may be added to the hydrocarbon retention system during engine cold start operation 22 be directed. Then, as soon as the emission control device 70 has reached its operating temperature in the plant 22 retained hydrocarbons 22 by means of the inlet 23 flushed to the engine, as described hereinafter.

With reference to 1 can the fuel system 18 one with a fuel pump system 21 connected fuel tank 20 include. The fuel pump system 21 can one or more pumps for pressurizing the injectors of the engine 10 , such as the exemplary injector shown 66 include delivered fuel. While only a single injector 66 is shown, additional injectors are provided for each cylinder. It is understood that the fuel system 18 may be a non-return fuel system, a returning fuel system, or various other types of fuel systems. In the fuel system 18 generated vapors may be flushed to the engine intake 23 by line 31 to the hydrocarbon retention plant 22 which is further described below.

The fuel tank 20 can accommodate multiple fuel blends, including fuel with a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, etc., and combinations thereof.

The hydrocarbon retention plant 22 may include one or more hydrocarbon retention devices, such as a hydrocarbon filter, which is configured to temporarily filter hydrocarbons from incoming gases. The hydrocarbon retention plant 22 can still have a ventilation opening 27 include which gases from the retention system 22 can conduct to the atmosphere when hydrocarbons from the outlet 25 and / or the fuel system 18 saved or filtered. The ventilation opening 27 can also allow fresh air into the hydrocarbon retention plant 22 is sucked when stored hydrocarbons from the outlet 25 and / or the fuel system 18 by means of a flushing line 28 and a purge valve 29 to the inlet 23 be rinsed. During this example the ventilation opening 27 In combination with fresh, unheated air shows, various modifications can be used. For example, heated intake air from an air filter box may be used. Further, heated exhaust may be used under selected conditions.

In system 6 can use different system configurations of hydrocarbon retention system 22 be used with various combinations of valves, sensors and the like. For example, various system configurations are described herein with reference to the following 3 - 7 shown. And while the different configurations of the 3 - 7 Different alternative features in certain combinations may show the different features of the 3 - 7 also combined with each other to form yet further exemplary configurations. Further, various additional components may be included in the intake, exhaust, and fuel system, such as a muffler downstream of the valve 24 ,

The motor vehicle system 6 can continue a tax system 14 include. The tax system 14 is shown as it is information from multiple sensors 16 (various examples of which are described herein) and how it receives control signals to multiple actuators 81 (various examples of which are described herein). For example, the sensors 16 an exhaust gas sensor 126 located upstream of the emission control device, a temperature sensor 128 and a pressure sensor 129 include. Other sensors, such as pressure, temperature, and composition sensors, may have different locations in the automotive system 6 be connected, as will be explained in more detail herein. As another example, the actuators may be a fuel injector 66 , a valve 28 , a valve 24 and a throttle 62 include. The tax system 14 can be a controller 12 include. The controller may receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or a code programmed therein corresponding to one or more routines. Exemplary control routines are described herein with reference to FIG 8th - 12 described.

The hydrocarbon retention plant 22 Can work to hydrocarbons from multiple sources, including the engine exhaust 25 and the fuel system 18 to store at the same time or during different operating conditions. In some operating conditions, such as during engine starts, when the emissions control device has not yet reached its light-off temperature (eg, a temperature at which the device reaches a selected, sufficiently high conversion efficiency for a particular exhaust gas constituent), exhaust from the outlet 25 to the hydrocarbon retention plant 22 and then through the ventilation opening 27 be directed to the atmosphere. In this way, an increased amount of cold start hydrocarbon emissions in the hydrocarbon retention plant 22 be stored while the exhaust gases, the emission control device 70 heat. Because as soon as the device 70 reached a sufficient operating temperature, exhaust gases are through the pipe 35 passed to the atmosphere and the hydrocarbon retention plant 22 is essentially shielded from the engine exhaust. In addition, in the fuel tank 20 generated fuel vapors for storage to the hydrocarbon retention plant 22 be routed before going to the engine inlet 25 fed and in the engine 10 to be burned. These different memory modes (from the outlet 25 and from the fuel system 18 ) may be carried out simultaneously or separately or in a combination thereof.

After shielding from the exhaust gas, the hydrocarbon retention system may 22 be connected to the engine inlet to supply fresh air through the ventilation opening 27 to suck and store stored hydrocarbons in the engine for combustion in the engine intake. Such purges may occur during selected engine operating conditions, as described herein.

Further details of the rinse and store process are described herein.

2 is a schematic diagram showing a cylinder of a multi-cylinder engine 10 shows. As with respect to 1 described, the engine can 10 at least partially by a control system that has a control unit 12 as well as input from a vehicle operator 132 by means of an input device 130 to be controlled. In this example, the input device includes 130 an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. A combustion chamber or cylinder 30 of the motor 10 can combustion chamber walls 32 with a piston positioned therein 36 include. The piston 36 can with a crankshaft 40 be connected so that a stroke of the piston is converted into a rotational movement of the crankshaft. The crankshaft 40 can be connected by means of a transmission system located therebetween with at least one drive wheel of a vehicle. Further, a starter motor by means of a flywheel with the crankshaft 40 be connected to a startup operation of the engine 10 to enable.

The combustion chamber 30 can by means of an inlet channel 42 Intake air from an intake manifold 44 take up and can by means of an exhaust manifold 48 Drain combustion gases. The intake manifold 44 and the exhaust manifold 48 can by means of a respective inlet valve 52 and exhaust valve 54 with the combustion chamber 30 be selectively connected. In some embodiments, the combustion chamber 30 Two or more intake valves and / or two or more exhaust valves. The intake manifold may include a purge path fluidly connected to the exhaust flow that allows purge vapors to enter the intake manifold 44 be supplied. While this example shows that the purge path downstream of the restrictor allows the manifold vacuum to draw in the gases, various others can Configurations are used. For example, in the case of a turbocharger engine, the purge lines may lead to a location upstream of the turbocharger compressor inlet.

In this example, the inlet valve 52 and the exhaust valves 54 by cam actuation by means of corresponding cam actuation systems 51 and 53 to be controlled. The cam actuation systems 51 and 53 may each comprise one or more cams and may include one or more systems of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT) Timing) and / or Variable Valve Lift (VVL) used by the controller 12 can be operated to change the valve operation. The position of the inlet valve 52 and the exhaust valve 54 can each be through position sensors 55 and 57 be determined. In alternative embodiments, the inlet valve 52 and / or the exhaust valve 54 be controlled by electric valve actuation. For example, the cylinder 30 alternatively comprise an intake valve controlled by electric valve actuation and an exhaust valve controlled by cam actuation, including CPS and / or VCT systems.

The fuel injector 66 is for feeding fuel directly into the combustion chamber 30 proportional to the pulse width of one by means of an electronic driver 68 from the controller 12 received signal FPW directly to the combustion chamber 30 shown connected. In this way, the fuel injector looks 66 one as a direct injection of fuel into the combustion chamber 30 known injection. The fuel injection valve may be installed, for example, in the side of the combustion chamber or in the upper part of the combustion chamber. Fuel may be the fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump and a fuel rail. In some embodiments, the combustion chamber 30 alternatively or additionally in the inlet channel 44 in a design, the one as a port injection of fuel into the intake passage upstream of the combustion chamber 30 known injection, arranged arranged fuel injection valve.

The inlet channel 42 can a choke 62 with a throttle 64 include. In this particular example, the position of the throttle 64 through the control unit 12 be changed by means of a signal that an electric motor or one with the throttle 62 provided actuator, a configuration often referred to as Electronic Throttle Control (ETC). That way, the throttle can 62 be operated so that the combustion chamber 30 In addition to other engine cylinders supplied intake air is changed. The position of the throttle 64 can the controller 12 be supplied by a throttle position signal TP. The inlet channel 42 can also have an air flow meter 120 and a manifold air pressure sensor 122 for supplying respective signals MAF and MAP to the controller 12 include.

An ignition system 88 can the combustion chamber 30 under selected operating modes by means of the spark plug 92 in response to a pre-ignition signal SA from the controller 12 provide a spark. Even if spark ignition components are shown, the combustion chamber 30 or one or more other combustion chambers of the engine 10 operated in some embodiments in a compression ignition mode with or without sparks.

An exhaust gas sensor 126 is with the exhaust duct 48 upstream of the emission control device 70 shown connected. The sensor 126 may be any suitable sensor for providing an indication of the exhaust gas fuel ratio, such as a linear oxygen sensor or UEGO (universal or broadband exhaust oxygen), a two-state oxygen sensor or EGO, a HEGO (heated EGO), an NOx, HC - or CO sensor. The emission control device 70 is along the outlet channel 48 downstream of the exhaust gas sensor 126 shown arranged. The device 70 may be a three-way catalyst (TWC), a NOx trap, various other emission control devices, or combinations thereof. In some embodiments, the emission control device may 70 during operation of the engine 10 be reset regularly by at least one cylinder of the engine is operated within a certain air / fuel ratio.

The control unit 12 is in 1 as a microcomputer, comprising: a microprocessor unit 102 , Input / output ports 104 , an electronic storage medium for executable programs and calibration values, which in this particular example is a read-only memory chip 106 shown is a memory 108 , a battery powered memory 110 and a data bus. The storage medium read-only memory 106 can be programmed with machine-readable data generated by the processor 102 to execute commands to perform the methods described below and other variants, which are expected but not specifically listed, represent. The control unit 12 can in addition to the already explained signals different signals from with the engine 10 connected sensors, including a measurement of the inducted air mass (MAF); an engine coolant temperature (ECT) from one with a cooling jacket 114 connected temperature sensor 112 ; an ignition profile pickup signal (PIP) from one to the crankshaft 40 connected Hallgeber 118 (or another type); a throttle position TP from a throttle position sensor; and a manifold vacuum signal (MAP) from a sensor 122 , An engine speed signal RPM may be provided by the controller 12 be generated from the signal PIP. The manifold pressure signal MAP from a manifold pressure sensor may be used to provide an indication of vacuum in the intake manifold.

As described above 2 only one cylinder of a multi-cylinder engine 10 and that each cylinder may analogously include its own set of intake / exhaust valves, fuel injector, spark plug, etc.

3 shows a first embodiment 300 hydrocarbon restraint system including hydrocarbon restraint devices such as the HC filter 310 , which is parallel to the exhaust pipe 35 downstream of the emission control device 70 is arranged, and the storage container 322 , An exhaust pipe valve 24 is located in the exhaust conduit to inhibit exhaust flow during a first mode of operation and to allow exhaust flow to flow during a second mode of operation. A bypass line 312 is upstream and downstream of the exhaust pipe valve 24 connected. Furthermore, the bypass includes 312 a first bypass valve 314 , a HC filter 310 and a second bypass valve 318 , In this example, the HC filter may be a brick 320 include. In other examples, the HC filter may include multiple bricks or other structures, such as activated carbon. Furthermore, the HC filter 310 also be a storage tank using micropores (0.5 nm pore size range) activated carbon or zeolites. The bypass line 312 leads through the ventilation opening 27 and optionally by valve 318 and direction 35 to the atmosphere.

Furthermore, the HC filter 310 by means of a channel 324 fluidic with a Spülspeicherbehälter 322 be connected. The rinse storage tank 322 may be configured to receive steam from the fuel system, such as by a conduit 328 leading to the fuel tank 20 leads. The channel 324 can a valve 326 include. The rinse storage tank 322 can by means of a line 330 and a valve 332 also be fluidly connected to the engine inlet. Analogous to the HC filter 310 can the storage tank 322 Activated carbon include, although this another, z. B. high, may have porosity.

During this example, two hydrocarbon restraint devices (eg HC filters 310 and rinse tank 322 ), various alternatives may be provided. For example, a single hydrocarbon retention device, such as a storage vessel, may be used, with the storage vessel serving to store both exhaust hydrocarbon and fuel tank vapors. Further, the two hydrocarbon restraint devices may each be storage tanks or may each be HC filters. Regardless of the particular configuration of the HC containment system, the hydrocarbon restraint devices may receive conducted cold start hydrocarbons and retain the hydrocarbons.

In one example, hydrocarbon restraint devices may include granular activated carbon contained in a plastic housing because the exhaust gas temperatures may be substantially lower than the full range of exhaust gas temperature occurring in the exhaust system.

The hydrocarbon retention plant 22 from 3 can be operated by a controller by selectively adjusting the various valves in multiple modes. For example, the following modes may be executed:

MODE A: Hydrocarbon storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 close and the valves 314 and optional 318 to open. In addition, the valve 332 closed. Exemplary operating conditions include the engine cold-start operation before the emission control device has reached a light-off temperature. In this mode, exhaust gas from the engine 10 through the HC filter 310 passed before it by means of the ventilation opening 27 exits to the atmosphere while the Spülspeicherbehälter 322 is shielded from the exhaust gas and the hydrocarbon retention system.

OPERATION B: Fuel vapor storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 open and the valves 314 and 318 shut down. The valve 332 can be closed, with fuel fumes only stored and not rinsed. Alternatively, the valve 332 be open at a controlled amount, allowing some fuel tank vapors are stored and some are supplied to the engine for burning. In this mode, at least some fuel tank vapors will pass through the purge storage tank 322 and passed the HC filter and retained there before passing through the vent 27 be drained.

OPERATION C: HC filter and / or storage tank flush

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 open and the valves 314 and 318 shut down. In addition, the valve can 332 be open at a controlled amount, allowing fresh air through the vent 27 is sucked to the HC filter 310 and the rinse storage tank 322 by 330 and valve 332 to the engine intake 25 to wash. In this way, the purged fuel vapors from the storage tank and / or the HC filter in the engine are burned while exhaust gas after treatment by the emission control device through the line 35 is directed to the atmosphere.

In an alternative embodiment, the plant may instead of the intake of fresh air by means of the ventilation opening 27 additionally or alternatively, for purifying stored hydrocarbons, pass exhaust gases to the vent opening to allow heated exhaust gas to heat the hydrocarbon retentive system and better to flush stored hydrocarbons. Such operation may be used during certain conditions, such as cold ambient temperatures. Further, under certain conditions, the system may intentionally direct exhaust gases during the storage mode for a longer duration to heat the hydrocarbon retention system to a higher temperature, thereby improving the subsequent purge operation. In one example, exhaust gases may be directed to the hydrocarbon retention system prior to a purge operation (even during non-startup conditions) to increase the temperature and increase the efficiency of the subsequent purge. This procedure can be used when the temperature of the hydrocarbon retardant falls below a threshold or when limited purge conditions exist.

Note that the configuration of 3 allows that through the HC filter 310 flowing gas back to the outlet 35 and out of the tailpipe. Thus, by using the valve 318 (which may be a lower cost, lower temperature valve compared to the other exhaust valves in the plant), which allows the exhaust gas to flow back to the exhaust pipe (or to a tail pipe location), various advantages are realized. For example, during cold start filter operation, the configuration allows sufficient flow without directing exhaust to a location other than the tailpipe. Further, by providing a separate channel for the purge stream inlet, it is possible to draw purge air from a location less susceptible to Waser intrusion.

Further, as the exhaust gas is directed back to the exhaust system, as in FIG 3 5, the HC filter is positioned upstream of the muffler, thereby reducing effects of muffler leakage on the performance of the pollutant system.

4 shows a second embodiment 400 the hydrocarbon retention plant 22 , In this configuration, a valve includes 24 a diverter valve that either blows exhaust through the line 35 to the atmosphere or to lead 412 passes. 4 shows the HC filter 410 parallel to the exhaust pipe 35 , downstream of the emission control device 70 arranged. The administration 412 is upstream of the valve 24 connected and includes the HC filter 410 ,

Furthermore, the HC filter 410 with the rinse tank 422 by channel 424 and valve 426 be fluidly connected. The rinse storage tank 422 may be configured to receive steam from the fuel system, such as by a conduit 428 leading to the fuel tank 20 leads. The rinse storage tank 422 can also with the engine inlet by means of a pipe 430 and a valve 432 be connected fluidly. The hydrocarbon retention plant 22 can also have a first pressure sensor 436 and a second pressure sensor 438 that with the line 424 are connected. In addition, a HC filter temperature sensor 440 be directly connected to the HC filter.

As schematically in 4 is shown is the vent 27 at least with a part of the line 35 thermally connected so that heat is transferred between them. In one example, the ventilation opening 27 to at least part of the line 35 be spatially adjacent.

The hydrocarbon retention plant of 4 can be operated by a controller by selectively adjusting the various valves in multiple operating modes. For example, the following modes of operation can be performed:

MODE A: Hydrocarbon storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 adjust to exhaust gas to the pipe 412 to conduct, as well as the valves 432 and 426 shut down. Exemplary operating conditions include the engine cold-start operation before the emission control device has reached a light-off temperature. In this mode, exhaust gas from the engine 10 through the HC filter 410 passed before it through the vents 27 exits to the atmosphere while the Spülspeicherbehälter 422 is shielded from the exhaust gas and the hydrocarbon retention system.

OPERATION B: Fuel vapor storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 adjust to exhaust through the pipe 35 to direct and the hydrocarbon filter 410 shield from the exhaust. Furthermore, the controller can control the valve 326 open and the valve 432 shut down. In this mode, at least some fuel tank vapors will pass through the purge storage tank 422 and the HC filter 410 directed and retained in these before passing through the vent 27 be drained.

OPERATION C: HC filter and / or storage tank flush

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 Adjust so that it exhaust through the pipe 35 conducts and the hydrocarbon filter 410 shield from the exhaust gas. Furthermore, the controller can control the valve 326 open and the valve 432 open controlled, allowing fresh air through the ventilation opening 27 is sucked in to the HC filter 410 and the rinse storage tank 422 by 430 and valve 432 to the engine intake 25 to wash. In this way, the purged fuel vapors from the storage vessel and / or the HC filter are burned in the engine, while exhaust gas after treatment by the emission control device through the line 35 is directed to the atmosphere. As mentioned above, heat may be added to the vent 27 be sucked air. In some examples, heat may be transferred by conduction, convection, forced convection, combinations thereof, or alternatively forms of thermal connection. In this way, when the system heats up to operating temperature, the heated air may release in the HC filter 410 and / or Spülspeicherbehälter 422 improve stored hydrocarbons.

5 shows a schematic representation of a third embodiment of the hydrocarbon retention system 22 , This embodiment is similar to that of 3 , except that the HC filter 510 two bricks 520 and designed to pass exhaust gases through the bricks in sequence, but to flush them in parallel. Specifically, the facility includes 5 the HC filter 510 , which is parallel to the exhaust pipe 35 downstream of the emission control device 70 is arranged. An exhaust pipe valve 24 , which in this example may be a throttle, is located to inhibit exhaust flow during a first mode of operation and to allow the exhaust flow to flow during a second mode of operation in the exhaust passage. A bypass line 512 is upstream and downstream of the exhaust pipe valve 24 connected. Furthermore, the bypass includes 512 a first bypass valve 514 , the HC filter 510 and a second bypass valve 518 , The bypass line 512 is by means of two parallel channels 534 and valve 538 also with the ventilation opening 27 connected.

Furthermore, the HC filter 510 by channel 524 with a rinse tank 522 fluidly connected. The rinse storage tank 522 may be configured to receive steam from the fuel system, such as by a conduit 528 leading to the fuel tank (not shown) 20 leads. The rinse storage tank 522 can also with the engine inlet by means of a pipe 530 and valve 532 be fluidly connected.

The hydrocarbon retention plant of 5 can be operated by a controller by selectively adjusting the various valves in multiple modes. For example, the following modes may be performed.

MODE A: Hydrocarbon storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 538 close and the valves 514 and 518 to open. Furthermore, the valve 532 closed. Exemplary operating conditions include the engine cold-start operation before the emission control device has reached a light-off temperature. In this mode, exhaust gas from the engine 10 (one after the other through the bricks 520a and then 520b ) through the HC filter 510 passed before it by means of the line 35 exits to the atmosphere while the Spülspeicherbehälter 522 is effectively shielded from the exhaust when the flow against the valve 526 is brought to a standstill.

OPERATION B: Fuel vapor storage

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 . 526 and 538 open and the valves 514 and 518 shut down. Valve 532 can also be closed. Thus, the exhaust gases from the storage tank 522 and the HC filter 510 isolated. In this way, at least some of the fuel tank vapors will pass through both the purge storage tank 522 as well as the HC filter 510 passed and retained in these before passing through the valve 538 and the ventilation opening 27 be drained. In particular, the fuel vapors are first passed through the storage tank 522 are then routed in parallel by the bricks respectively 520a and 520b headed before going through 27 be drained. In this way, fuel tank vapors due to the different directions of the exhaust stream and the fuel tank vapors, at least Brick 510a , stored in different concentrations at different points of the filter

OPERATION C: HC filter and / or storage tank flush

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 and 538 open and the valves 514 and 518 shut down. Furthermore, the valve 532 be open at a controlled amount, allowing fresh air through the vent 27 is sucked to the HC filter 510 and the rinse storage tank 522 by 530 and valve 532 to the engine intake 25 to wash. In this way, the purged fuel vapors from the storage tank and / or the HC filter in the engine are burned while exhaust gas after treatment by the emission control device through the line 35 is directed to the atmosphere. Again, fresh air is directed in a direction opposite to the B mode, parallel to the bricks 520a and 520b passed before being combined and through the rinse tank 522 is directed. In this way, the purging of vapors takes place in a direction opposite to the fuel tank vapor storage in both Bricks and in one of the exhaust gas hydrocarbon storage in at least one Brick ( 520a ) opposite direction.

Such different storage and purging directions, which utilize both serial storage and parallel purging, may allow for improved storage and release, thereby improving the efficiency of the engine and emission control system.

6 shows additional details of an example of the third embodiment of FIG 5 , Similar components are designated accordingly. In this example, the valves are 24 . 518 and 514 Low-pressure throttle valves. The HC filter includes two bricks 520a , b with activated carbon pellets 612 , A vacuum regulator 614 is with the valves 24 . 514 and 518 connected and can be designed to valve 24 close whenever the valves 518 and 514 are open, and vice versa. The vacuum regulator 614 can in one example by the control unit 12 be operated electronically.

Continue with 6 are a first pressure sensor 540 and a second pressure sensor 542 with the inlet 616 and the outlet 618 connected to the HC filter. An on-board diagnostic (OBD) sensor 620 can be between the first and the second brick respectively 520 aund 520b be connected. The OBD sensor may measure the gas pressure, the gas composition or a combination thereof in the HC filter.

In this example, the HC filter 510 after a underfloor catalyst, but be positioned in front of a muffler. Furthermore, the length of the lines from the outlet 35 > 12 inches to reduce the exhaust gas temperature from 800 ° C to 100 ° C and allow plastic parts. Furthermore, coal may also serve to reduce noise when a muffler in the outlet is bypassed.

Still further with an example, the exhaust flaps at the storage tank inlet and outlet (FIGS. 616 . 618 ) are made of plastic and can be integrated into a plastic housing of the filter / storage container. The device may include a rubber seal or a rubber o-ring to help seal around the housing where the door would close and to seal around the plastic door due to reduced temperature. The housing of the device 510 may include 1.5 inch ID inlet / outlet tubes, molded protrusions in the spring portion for a sensor and poppet valve, molded channels on the air inlet cones, screens on both sides of the carbon bed for permitting flow through the reservoir, and actuated outlet flaps. That with 524 connected inlet valve may be positioned between the packed beds. At this point, the OBD sensor 620 watch the loading and unloading of the beds. In one example, when the plastic exhaust valves seal, the poppet valve lets in air from the air purifier box. The fresh air inlet at each cone is disconnected from the inlet air source downstream of the outlet valve. The outlet may lead to the fuel tank vapor purge system, for example, either in series into the storage vessel 522 or in parallel.

7 shows a fourth embodiment of a hydrocarbon retention system 22 , This example is similar to that of 4 although in the bypass 712 different valve and line configurations can be used with two HC filters. In detail, the valve works 24 in this example as a diverter valve to either one Exhaust gas flow through the pipe 35 to allow the atmosphere or the exhaust gas flow to line 714 and valve 716 to lead. In this example, the valve is 716 another diverter valve, which either the connection between the line 714 and the line 740 or the line 714 and the line 742 allows. The bypass 712 further includes first and second HC filters 726 respectively. 728 , There is also a valve 726 for controlling a flow leading to or coming from the purge storage tank (not shown), which then leads to the fuel tank and intake manifold, analogous to the other exemplary configurations described above. Thus, fuel vapors from the fuel tank can be supplied to the first and second filters in this order 726 and 728 be routed and rinsed in the reverse order.

In 7 are the two filters 726 and 728 designed with different HC filter characteristics. For example, filters 726 compared with filters 728 consist of activated carbon with greater porosity to absorb larger HC molecules. In this way, the gases can only during storage by 726 and then through 728 be routed so that the size of the HC molecules in the gas is increasingly reduced. Furthermore, since it may be difficult to remove stored HC molecules from the activated carbon having the smaller pores, the activated carbon having the smaller pores may be buffered by the activated carbon having the larger pores to prevent HC molecules from becoming irreversible the smaller pores are absorbed. Furthermore, the adsorption of smaller HC species into the filter 728 at higher pressures. Thus, the inlet pipe diameter of the diverter valve 716 be sufficiently sized to the filters to provide a sufficient target pressure during the storage and rinsing process.

The configuration of 7 looks for both filters 726 and 728 also an opposite flow direction for the storage and rinsing before. In detail, divert the bypass valves 24 and 716 the exhaust gas during storage of HC in the exhaust gas 714 and then to filter 726 and then too 728 before using it 27 is drained. While flushing the filters, the valves are adjusted to allow fresh air through the vent 27 , the filter 728 and then the filter 726 to guide before this through 726 and then directed to the inlet. In this way, improved storage and release of HC can be effected, especially in view of the various properties (eg, porosity) of the filters. The configuration of 7 can work in each of the modes A, C

While in an example 726 and 728 can each be HC filter, two coal storage tank can be used. Alternatively, as mentioned, zeolites may be included. For example, the storage tank 726 be designed to adsorb cold-starting propylene and higher mass hydrocarbons instead of a separate device. Microporous activated carbons in 728 adsorb hydrocarbons of smaller size, but may be better protected than 726 in row. Further, purging the filters with preheated air from an air-cleaning box or vehicle hot exhaust gas in a direction opposite to the adsorption flow may provide further improved performance.

While this example has two filters in the configuration of 7 shows, more or less can be used.

In a particular example, the device may 726 a coal storage vessel (greater porosity) to capture HC molecules of medium to large size, followed by a storage vessel 728 for activated carbon with smaller pores. During storage, gases first pass through 726 and then too 728 , The removal takes place in the opposite direction. In this way, the larger pores better protect the smaller pores and reduce irreversible adsorption of larger HC molecules into the smaller pores. The adsorption of small HC species into the small pore medium can better respond to pressure, such as about 5 MP, which can be provided by sizing the inlet tube diameter from the diverter valve to the storage vessels. Similarly, removal of the HC species can benefit from an elevated temperature, such as by heat transfer of exhaust gas or by using at least some exhaust gas, such as during idle conditions.

It is understood that with reference to 3 - 7 MODE A can not only work to store HC from the exhaust gas in the hydrocarbon retention plant, but also can significantly heat the plant. This can be used advantageously to the hydrocarbon retention plant 22 prepare for a subsequent rinse, as increased temperature may cause stored hydrocarbons to be released more easily.

Furthermore, while the examples of 3 - 7 combined rinsing of the fuel tank vapors and the stored exhaust hydrocarbons show that they are independently purged in alternative configurations. For example, the exemplary HC filters may be connected in parallel to a purge line by means of a purge line exemplary storage tanks are rinsed, whereby a separate and / or independent purging of the various hydrocarbon storage facilities is made possible. For example, a hydrocarbon restraint may be purged without purging a second hydrocarbon restraint. Furthermore, in some example configurations 3 - 7 the fuel tank vapors in the purge storage tanks are purged sufficiently faster than the hydrocarbons in the HC filters. Thus, during the initial purging, the learned vapor amount / concentration may be used to determine the amount of fuel vapors stored in the storage vessel, and then, during a later portion of the purging operation (if the storage vessel is sufficiently purged / empty), the learned Steam amount / concentration can be used to estimate a state of charge of the HC filters (which was generated during the last storage operation, such as the last cold start event).

While the examples of the 3 - 7 furthermore, not simultaneous storage of the exhaust hydrocarbons and purging of the retention system 22 For example, in alternative embodiments, some stored hydrocarbons may be purged while storing other hydrocarbons.

The following procedure of 8th - 14 may be implemented using systems, components, and devices described herein, but may alternatively be implemented using other suitable systems, components, and devices.

Referring now to 8th is a routine 800 for controlling engine operation, fuel vapor control, and exhaust emission control. The routine 800 may operate during a warm-up condition, such as while the engine or exhaust is warming from ambient temperatures to its normal operating temperature range.

First, the routine determines at 810 , whether an engine start is present. For example, the routine may determine if the engine is starting from hibernation. Additionally or alternatively, the routine may determine whether the engine was started by means of engine cranking operation. If there is an engine start, the routine is approaching 812 where the routine estimates or measures the temperature of the emission control device based on various parameters. In one example, the routine may determine the temperature of the emissions control device based on an engine shut-down time (wet-out time), ambient temperature, engine coolant temperature, and intake air fill temperature. Alternatively or additionally, the routine may determine the temperature of the emission control device based on one or more in the exhaust duct 35 or the exhaust manifold 48 determine the exhaust temperature sensor (s) to be determined. Furthermore, the routine may determine the temperature of an emission control device based on a temperature sensor attached to the emission control device.

at 814 the routine determines a temperature threshold based on the operating conditions. An exemplary manner of determining the temperature threshold is described herein with reference to FIG 9 described. Alternatively, a fixed temperature threshold can be used. In one example, the temperature threshold correlates to a catalyst initiating temperature. Next, the routine is approaching 816 to determine whether the storage of hydrocarbons generated in the exhaust gas in the restraint system 22 is activated and, if not, to end this process. Such a process may be based on various conditions, including whether a hydrocarbon storage capability of the containment facility 22 is greater than a threshold, to be adjusted. For example, the routine may be storing in the containment facility 22 allow if the storage facility 22 was purged during the previous engine operation. In addition, the routine may include storing hydrocarbons in the containment facility 22 Allow if the temperature of the restraint system 22 is lower than a maximum storage temperature. Furthermore, the routine may include storing exhaust hydrocarbons in the containment facility 22 based on a fuel property of the fuel combusted in the engine, such as an amount of alcohol in the fuel, wherein the amount of alcohol in the fuel may be learned during a previous engine operation. In this way, the end of passing exhaust gas to the hydrocarbon retention plant 22 adapted to take advantage of the different storage properties of different fuels. For example, the routing may continue to higher storage levels or for a longer duration when higher alcohol fuels are burned as compared to lower alcohol fuels. Furthermore, the routine may include storing hydrocarbons in the containment facility 22 when an engine soak time (eg, an engine / vehicle shutdown time) is greater than a threshold amount. In this way, the engine can, for example, during hot restart exhaust gases through the exhaust system 35 direct and the retention system 22 bypass.

If the answer is 816 Yes, the routine is getting closer 818 to determine if the temperature of the emission control device 70 lower than at 814 determined threshold temperature. If so, the routine is approaching 820 before one or more of the exhaust valves (eg. 24 ) to exhaust gas through the hydrocarbon retention plant 22 and in particular to pass through one or more hydrocarbon filters. For example, the control system 14 depending on the plant configuration, adjust one or more exhaust valves to exhaust from downstream of the emission control device 70 to and through the hydrocarbon retention plant 22 before it is released to the atmosphere or directed to it. In one example, the routine operates the plant in MODE A, which is described hereinabove. Further, the plant may operate substantially with spark timing at peak torque times, or may operate at a spark retard amount, depending on operating conditions, as described herein with reference to FIGS 10 are described.

Next up is the routine 822 a lot of in the hydrocarbon retention plant 22 stored hydrocarbon, such as the amount of in the HC filter 310 stored hydrocarbon. The routine may determine the amount of stored hydrocarbons based on the exhaust flow rate, the exhaust temperature, the temperature of the hydrocarbon retention system 22 , which estimate engine speed and various other parameters.

If the answer is either at 816 No is or at 818 Yes, the routine is approaching 824 to operate the exhaust valves to exhaust from the emission control device 70 to guide them so that they retain the hydrocarbon retention system 22 bypass and the atmosphere through the line 35 be supplied. Further, as noted herein, the exhaust may be directed through various additional emission control devices and / or mufflers before being delivered to the atmosphere. In one example, the routine operates during the step of 824 the engine to increase the exhaust gas temperature, whereby the ignition time is delayed sufficiently behind the MBT time and the combustion is performed at a slightly lean air-fuel ratio in the combustion chamber. Furthermore, the step of 824 cause the system to not operate in MODE A, although the system may or may not operate in modes B and C, as further described herein 8th is described.

From 824 or 822 moves the routine 826 to determine whether the purging of the stored hydrocarbons from the hydrocarbon retention system 22 to be executed (for example, if the system can operate in MODE C). In an example, the routine of 11 an example of determining whether the hydrocarbon retention plant 22 to rinse. Initiation of purging of the hydrocarbon retention plant 22 may be based on various engine and vehicle operating parameters, including those in the containment system 22 stored amount of hydrocarbon (such as those in the HC filter 310 stored amount of hydrocarbons), the temperature of the emission control device 70 , the temperature of the hydrocarbon retentive system, the fuel temperature, the number of starts since the last purge, the fuel properties (such as the amount of alcohol in the combusted fuel) and various others. In one example, the routine determines at 826 whether the exhaust gases during the current engine start to the hydrocarbon retention system 22 were conducted. In one particular example, the initiation of purging may be adjusted to be initiated at higher temperatures as the amount of alcohol in the fuel increases.

If the answer is 826 Yes, the routine is approaching 828 to operate the exhaust valves so that fresh air through the hydrocarbon retention system 22 and in the inlet channel 42 of the motor 10 is sucked, which may include operation of the plant in C mode. The motor 10 then works to admit the vapors together with the injected fuel and the intake air and to carry out the combustion of the same. Next up is the routine 830 the amount of purged hydrocarbons from the hydrocarbon retention plant 22 (which may be associated with an HC filter and / or a purge storage tank) based on various parameters, including the amount of stored hydrocarbons and feedback information from the exhaust gas fuel ratio sensors. In one example, the feedback from an exhaust gas oxygen sensor may be used to learn or update the estimated amount of hydrocarbons stored in the HC filter to determine the degradation of the HC filter based on such an estimate. Further, the routine may also adjust the throttle control of the engine to adjust an amount of purge gases that are drawn through a purge storage tank, HC filter, or both.

At the answer no at 826 No or from 830 moves the routine 832 in front. at 832 the routine determines whether hydrocarbon vapors generated by the fuel tank are to be purged if such vapors do not 828 were flushed or at 828 were not sufficiently flushed. A exemplary routine for determining whether vapors generated by the fuel tank are to be purged is with reference to FIG 12 described. If the answer is 832 Yes, the routine is approaching 834 to operate the exhaust valves to vapors generated by the fuel tank from the hydrocarbon retention system 22 to rinse, which may include operating the plant in MODE C. Otherwise, the routine comes in response to no 832 or from 834 to the end.

While this is in 8th is not specifically illustrated, the control system may also operate the plant in MODE B if the plant is not operating in A or C mode. Alternatively, MODE B may be selectively activated based on various operating conditions, including ambient temperature, fuel temperature, and others.

In addition, by appropriate consideration of the temperature, it is possible to further provide for controlling the routing of exhaust gas to the hydrocarbon retention system and purging the hydrocarbon retention system to the engine intake to account for warm engine restart conditions. For example, the system may consider the engine coolant temperature and the catalyst temperature when activating the routine and initiating purging such that when the coolant temperature is above a warm engine restart threshold and / or the catalyst temperature is above a warm engine restart threshold, then Exhaust gas to the hydrocarbon retention system is deactivated and purging is initiated as soon as the engine start / stop is completed.

Referring now to 9 becomes routine 900 for determining a temperature threshold, below the exhaust gases to the hydrocarbon retention plant 22 can be directed described. First, the routine determines at 910 a fuel composition. In one example, the routine may include an alcohol concentration and / or fuel mixture in the tank 20 of stored fuel. Alcohol concentration may be learned based on feedback from the exhaust oxygen sensors, which provide an indication of a stoichiometric air / fuel ratio shift. Additionally or alternatively, the routine may determine an alcohol concentration of the fuel based on a fuel concentration sensor. It should be noted that the routine can determine a relative amount of alcohol in a gasoline fuel or various other fuel compositions.

Next, the routine determines at 912 a fuel temperature. In one example, the routine may determine the fuel temperature of one with the fuel tank 20 measure the connected fuel temperature sensor. Alternatively, the routine may estimate the fuel temperature based on various parameters, including engine coolant temperature, ambient air temperature, and / or various others.

Next, the routine determines at 914 a temperature threshold based on the fuel temperature and the composition / construction of 912 respectively. 910 , In addition, the routine may determine the threshold based on additional operating conditions, including aging of the catalytic material of the emission control device 70 , In one example, the routine may increase the temperature threshold as the amount of alcohol in the fuel mixture increases. In this way, it is possible to adjust the temperature range for the exhaust gas to a hydrocarbon filter in the hydrocarbon retention plant 22 is directed. Specifically, such an operation may take advantage of the different storage characteristics of the filter as the amount of alcohol in the fuel changes. For example, fuels may have different adsorption and / or desorption characteristics with varying alcohol content. Further, water in the exhaust gas may affect the temperature at which storage / release of hydrocarbon species occurs. As the alcohol content of the fuel changes, various HC chains may be generated in the exhaust gas, thereby producing the different storage / release characteristics. In one particular example, HCs may be filtered to higher temperatures as the alcohol content in the fuel increases and, therefore, termination or reduction of MODE A operation may be delayed to higher elevated alcohol levels in the fuel.

Referring now to 10 becomes an exemplary routine 1000 for controlling the combustion air-fuel ratio during engine startup, based on the type of exhaust passage and / or purge of the hydrocarbon restraint system.

First, the routine determines at 1010 Whether the engine is just starting, as for example with reference to 810 is described. If this is the case, the routine is approaching 1012 before to determine if the plant gas to the hydrocarbon retention plant 22 directs (eg whether operation is in MODE A). If this is the case, the process is approaching 1014 to determine the combustion air / fuel ratio based on engine coolant temperature and various other parameters. Next, the routine works 1016 in which selected air / fuel ratio with reduced or no spark retard, such as by operating at MBT timing, possibly even during conditions where the temperature of the emissions control device (eg, catalyst in the exhaust) is substantially below its light off temperature. In one example this can be done with 1014 Initially, the selected air / fuel ratio may initially be lean during takeoff, and after starting and ramping up the engine speed, the selected air / fuel ratio may be approximately stoichiometric or slightly rich. Alternatively, the fuel / air ratio may be based on the amount of in the hydrocarbon retention system 22 stored hydrocarbons (such as the amount of in the HC filter 310 stored hydrocarbons). For example, with increases in the hydrocarbon retention plant 22 amount of hydrocarbon stored, the combustion air / fuel ratio to be adjusted accordingly higher (eg less fat or leaner).

If the answer is 1012 No, the routine is approaching 1018 to determine if the temperature of the emission control device 70 is lower than a light-off temperature. If the answer is 1018 No, the routine continues to operate the engine to burn an approximately stoichiometric air / fuel ratio with selective adjustment of spark retard (eg, substantially no spark retard, unless required for knock damping, speed reduction, etc.). If the answer is 1018 If yes, then the routine is approaching 1022 to operate the engine so that it has a near stoichiometric or slightly lean fuel / air ratio with more retarded ignition timing than when operating at 1016 and or 1020 burns. Otherwise, the routine will operate the engine 1020 such that it burns a stoichiometric fuel / air ratio with selective adjustment of retard ignition, with less delay than at 1022 , For example, the ignition times may be delayed by an amount based on the catalyst temperature.

As yet another example, the plant may thus operate in multiple ignition retard modes based on whether exhaust gases are directed to the hydrocarbon retainer. For example, the modes may include a first mode wherein the routine directs exhaust gases to the hydrocarbon containment system and operates during at least a portion of the first ignition mode at a first control time and at a first engine / exhaust air / fuel ratio; and a second mode in which the routine bypasses the hydrocarbon retention system and at least during a portion of the second mode with ignition at a second control time more delayed from the first control time or at a second engine / exhaust air / fuel ratio leaner than the first exhaust gas fuel / air ratio is working. In a particular example, the second mode is performed after the first mode, both during a common engine start, wherein the first mode is performed at a lower temperature of the emissions control device than the second mode. Further, the first air / fuel ratio may be lean during a first part and may be stoichiometric or rich during a second part of the mode. Alternatively, the first mode may be performed during a first engine start, and the second mode may be performed during a second engine start, wherein the hydrocarbon retarder may have stored a greater amount of hydrocarbons during the second start than during the first start.

From 1020 Determines the routine next 1024 whether flushing the restraint system 22 including flushing one or both of the stored fuel tank vapors and the stored exhaust hydrocarbons. If this is the case, the routine is approaching 1026 where the control system adjusts the fuel injection amount in response to feedback from one or more exhaust gas oxygen sensors to determine stoichiometric combustion and the learning of an amount of hydrocarbons released from the containment system 22 be rinsed, and / or a lot of in the retention system 22 to maintain stored hydrocarbons. Furthermore, the routine may adjust the throttle position in response to an amount of fresh air drawn through the hydrocarbon containment system. For example, the routine may close the throttle when the purging operation is initiated to compensate for additional flow.

In one example, the engine may set a desired fuel / air ratio by operating some cylinders at a leaner than the desired fuel / air ratio (eg, stoichiometric) and some cylinders in a richer than the desired fuel Provide air / air ratio. Such operation may be advantageous in that it may generate additional exothermic exhaust heat while still providing a stoichiometric exhaust air / fuel ratio. In one example, such split fuel / air ratio operation may be provided during 1016, for example, to facilitate increased heating of the emissions control device. Furthermore, by using an HC filter in the retention system 22 for example, all remaining hydrocarbons, which the device 70 leave, be filtered to maintain the desired emission levels.

Referring now to 11 is a routine for determining whether the hydrocarbons produced in the exhaust gas from the retention system 22 to be rinsed described. In one example, the routine of FIG 11 whether to stop fuel tank vapor storage (eg, MODE B) and to proceed to purging (eg, MODE C).

First, the routine determines at 1110 whether an HC retainer, such as an HC filter or a storage tank, the plant 22 was operated to store hydrocarbons during engine startup. If this is the case, the routine is approaching 1112 to determine if the system is currently flushing fuel tank vapors. If this is not the case, the routine is approaching 1114 to determine if an exhaust gas temperature, such as the temperature of the emission control device, is above a threshold temperature, such as the threshold of 818 , lies. The threshold value may be adjusted, for example, based on the alcohol content of fuel in the fuel tank and which is injected into the engine.

If the answer is 1114 Yes, the routine is approaching 1116 before, to determine if the amount of in the containment system 22 stored hydrocarbons (for example, the amount of in the HC filter 310 stored hydrocarbons) is greater than a threshold value. If this is the case, the routine is approaching 118 before to determine if the fuel / air ratio of combustion in the engine 10 is about the stoichiometric ratio. If this is the case, the routine is approaching 1120 to purge the containment system, such as to purge an HC filter and / or storage tank (eg, to operate in MODE C).

In one example, the operation of 11 after starting the engine or during starting conditions, such as during start-up conditions with a hot engine.

Referring now to 12 is a routine for determining whether the hydrocarbons generated in the fuel tank from the restraint system 22 to be rinsed described. In one example, the routine of FIG 12 whether to stop fuel tank vapor storage (eg, MODE B) and to proceed to purging (eg, MODE C). In one example, the routines of the 11 and 12 coordinated with each other, such as when fuel tank steam purging and purging of hydrocarbon generated in the exhaust gas occur simultaneously. In another example, the routines of 11 and 12 run independently of each other, for example, when fuel tank steam purging and purging hydrocarbon generated in the exhaust gas occur independently of each other.

First, determine the routine 1210 whether an HC retainer, such as an HC filter or a storage tank, of plant 22 is being rinsed. If so, the routine ends. Otherwise, the routine gets closer 1212 to determine if there is an engine start, such as described herein. If this is not the case, the routine is approaching 1214 to coordinate fuel vapor purging with adaptive learning of fuel injector failures, MAF sensor errors, etc., and then the routine advances 1216 in order to carry out the rinsing of fuel tank vapors to the inlet, which at 1214 was coordinated.

If the answer is 1212 Yes, the routine is approaching 1218 to determine if the combustion air-fuel ratio is approximately equal to the stoichiometric air-fuel ratio (see 10 ). If this is not the case, the routine will not allow flushing, for example, if HEGO sensors are used, it may be difficult to control the air / fuel ratio in the presence of a purge. If this is the case, the routine is approaching 1220 to determine if the plant is currently working to exhaust gases through the containment facility 22 to lead. If so, the routine ends (in the case where purging and storage do not occur simultaneously). Otherwise, the routine gets closer 1216 to flush the containment system to the inlet.

Referring now to 13 For example, a routine is described for determining whether exhaust gases reach the hydrocarbon retention system during conditions other than engine starting operation, such as other engine operating conditions where the engine is rotating and / or the vehicle is traveling 22 to lead. The routine of 13 may be used after start-up / warm-up operations of the engine, such as those described hereinabove.

For example, with reference to 13 described operation during cylinder valve deactivation conditions of one or more cylinders (eg, operation of a variable displacement engine (VDE)), in which the temperature of an emission control device may fall below an activation or light-off temperature, be advantageous. Under such conditions, the remaining active cylinders may operate stoichiometrically or slightly rich and the exhaust gases may enter the retention system 22 to the Saving excess hydrocarbons, which emerge from the cooled emission control device supplied. Further, during operation of fuel cut-off during deceleration (DFSO) or after reactivation of DFSO cylinders, a significant amount of fresh, oxygen-rich gas may be stored in the emissions control device, thereby reducing the catalytic reaction of emissions from the engine as well Temperature is reduced, be beneficial. This may be particularly advantageous in reactivating combustion after a DFSO, wherein the combustion air-fuel ratio during the reactivation is substantially rich to reduce the stored oxygen and restore the desired oxygen storage condition of the catalyst. The operation of 13 may also be used during excessive catalyst temperatures (such as when the catalyst temperature is above the maximum allowable temperature for the current conditions), with the engine operating in rich mode to reduce the catalyst temperature.

In yet another example, the routine of the exhaust gases may be to the hydrocarbon retention system 22 during periods other than the engine startup operation to the hydrocarbon retention system 22 to heat for subsequent rinsing. For example, once the hydrocarbon retention system 22 is sufficiently heated, the rinsing operation can be activated. This may be advantageous when the hydrocarbon retention system 22 below a threshold temperature and would otherwise cause slow and / or inefficient hydrocarbon release and / or desorption.

Referring now specifically to 13 determines the routine at 1310 whether there is an engine start, as described herein, for example. If this is the case, the routine is approaching 1312 before to determine if the hydrocarbon retention system 22 has been purged since the engine started the present engine operation and / or whether the amount of hydrocarbons and fuel vapors estimated to be in the plant 22 are stored below a threshold. For example, the routine may determine if the amount of in the HC filter 310 stored hydrocarbons is below a threshold.

If this is the case, the routine is approaching 1314 to determine if selected conditions exist. In one example, the selected conditions include when there is an increased potential for hydrocarbon breakthrough from the emissions control device 70 above a threshold. In another example, the selected conditions include fuel cutoff of one or more cylinders when decelerating and / or reactivation after such conditions. In yet another example, the selected conditions include when the exhaust air-fuel ratio from the engine is sufficiently substoichiometric (eg, richer than a threshold). In yet another example, the selected conditions include when one or more cylinders are deactivated, for example, when intake and exhaust valves are closed during the 4-stroke cycle. If this is the case, the routine is approaching 1316 to operate the exhaust valves so that exhaust gas through the hydrocarbon retention system 22 (eg working in OPERATING MODE A).

In this way, an improved emission can be achieved even during non-start conditions of the engine. Furthermore, it is understood that additional rinsing after the memory operation of 1316 during the following engine operation, as soon as the operation at 316 has ended.

In one particular example, during conditions other than engine startup wherein the catalytic emissions control device is above its light-off temperature, the routine may direct exhaust gas to the hydrocarbon holdup system when the temperature of the hydrocarbon holdover system is below a threshold, and the process continues until the hydrocarbon holddown system reaches a threshold washout temperature and then the effluent discharges exhaust gases to the atmosphere bypassing the hydrocarbon plant and flushes the hydrocarbon plant to the engine intake.

As in 14 mentions, the control system may be a determination of degradation of the restraint system 22 allow, for example, to detect and distinguish a degradation between a rinse tank and a HC filter. In some examples, the purge hydrocarbon concentration learned from feedback of the exhaust gas oxygen sensor and the adjustment of the fuel injection may provide independent estimates of hydrocarbon storage, for example, when a fuel tank container (eg, a fuel tank) (e.g. 422 ) a different temperature than an HC filter (eg. 310 ) having. Alternatively, the amount of hydrocarbon harvested during purging may be used to determine performance of an HC filter that has been loaded and then purged during a condition with little or no fuel tank vapor generation before the fuel tank vapors have been sufficiently purged. In another specific example, the HC filter may be based on detecting a change in a temperature condition of gas during purging of gases through the filter be diagnosed. Hereinafter, various examples as well as additional diagnostic approaches will be described.

In the following examples, the diagnostics will be made with reference to the example of a carbon-based hydrocarbon filter used in the containment plant 22 is described. Further, the operation will be described in the example in which after a starting operation, the exhaust gas flow is diverted through the HC filter until the emission control device is sufficiently warmed up and attained a desired conversion efficiency. Further, after storage, the retained hydrocarbons are then purged back into the engine by flowing air through the HC filter for combustion. The purge stream may be in series or in parallel with the charcoal canister purge of the evaporative emissions generated in the fuel tank. However, the following diagnostics can also be applied to various other system configurations and modes.

The following diagnostics can be used as function and / or threshold monitoring. Feature monitoring can determine if a device is connected and functioning as expected, while threshold monitoring can determine the effectiveness of the emission control device.

One possible degradation mode may include vibration and mechanical damage to the carbon in the HC filter - e.g. For example, coal granules can break and wear out. This may reduce the filter's HC filtering capability if the coal granules break apart and may be lost from the tailpipe. If enough coal is lost or compressed and the volume of the filter is no longer filled, part of the exhaust gas can bypass the coal bed and the tailpipe emissions can increase. Thus, one approach uses monitoring that detects a loss of coal volume as threshold monitoring.

In a first approach, the control system may measure the temperature at the outlet of the HC filter during filtering and purging. After a cold start, the temperature at the outlet is expected to rise as the exhaust system warms up. This indicates that the system is connected to the exhaust system and that the valves used to divert the flow to the filter are functioning. After allowing the current to bypass the filter, the temperature should stabilize, indicating that the valves have completed their cycle properly. A further increase in temperature would indicate that the filter is still exposed to exhaust gases. During the rinse cycle, the temperature should drop when fresh air is introduced into the filter.

In a second approach, the pressure differential across the carbon bed of the HC filter during retention or flushing may be measured as an indication of the presence of a flow restriction due to the coal. A coal loss would lead to a decrease in the pressure difference at a given flow rate. One or more pressure sensors may be installed upstream and / or downstream of the HC filter.

In a third approach, a fuel vapor / hydrocarbon sensor may be used. For example, an HC sensor in the filter outlet may directly measure the effectiveness of the filter during the filter, as degradation of the filter results in an increase in HC breakthrough at the vent 27 would lead. Modeling of the concentration and composition of the exhaust gas as a function of speed / load / spark retardation / temperatures and / or total fuel consumed since start along with the expected decrease of the HC upstream of the filter due to catalyst initiation may be used to increase the capability of threshold monitoring improve. Alternatively, an empirical model of the expected HC from the filter could be used.

In a fourth approach, temperature sensors positioned before and after the HC filter may provide an indication of a temperature difference during the phases of the filter (eg, due to adsorption) and purging (eg, desorption). The temperature difference may also be affected by the percentage of the current that is adsorbed and desorbed on the coal bed (primarily water and HC). In other examples, temperature deviations of expected or estimated values may be used. In the examples employing an HC filter in the exhaust system with a downstream temperature sensor, the system may utilize an inferred exhaust temperature at the filter outlet to produce a temperature difference between the inferred and actual temperature at the filter outlet. Then the system can diagnose the adsorption function based on this temperature difference. Further, due to possible errors in temperature estimates, the determination of a temperature shift may be based on the initial inlet temperature detected by the temperature sensor and then taking into account a measured temperature rise compared to an estimated temperature rise during selected conditions, for example, storage or purging. It should also be noted that in some examples the exhaust gas fuel ratio sensors may be operated as a temperature sensor under selected conditions.

In a fifth approach, a position measurement of the HC filter can be used. Specifically, to reduce the damage to the coal in the filter and / or container, the devices may include a floating end plate and one or more springs to maintain some pressure on the coal. If the coal degrades despite these measures, the decrease in volume may result in a change in the position of the end plate (s) and a decrease in the force exerted by the spring. Various methods of detecting the motion can be used to detect the loss of coal. In one example, these may include a position sensor, a thin wire that would break as the spring is extended, contacts that would open as the plate moves, transducers for measuring spring force, or strain gauge type devices incorporated into the spring.

In a sixth approach, probes that measure the carbon bed conductivity can be used to provide an impedance measurement that would increase with loss of spring pressure or a decrease in carbon volume. The resistance between two contact surfaces placed on top of the container may show a greater increase when the bed has settled sufficiently to provide a bypass path for the exhaust gases. In one example, the conductivity may be measured during selected conditions, for example, during heating or after heating.

It should be appreciated that the example control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The specific routines described herein may represent one or more of a number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Therefore, various illustrated operations, steps, or functions may be performed in the sequence shown or in parallel, or in some cases omitted. Similarly, the order of processing is not necessarily required to realize the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the operations or functions shown may be repeatedly executed depending on the particular strategy employed. Furthermore, the operations described may graphically represent a code to be programmed into the machine-readable storage medium in the engine control system.

It should be understood that the configurations and routines disclosed herein are exemplary in nature and that these specific embodiments should not be construed as limiting, as numerous modifications are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, boxer engines and other types of engines. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various systems and configurations, as well as other features, functions, and / or properties disclosed herein.

In particular, the following claims disclose certain combinations and subcombinations which are considered to be novel and not obvious. These claims may refer to "an" element or "first" element or equivalent thereof. These claims are to be understood to include integrating one or more such elements, neither requiring nor excluding two or more of these elements. Other combinations and sub-combinations 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 from the scope of the original claims, are also considered to be within the scope of the present disclosure.

Claims (16)

Method for operating an engine ( 10 ) with an inlet ( 23 ), an outlet ( 25 ) and a hydrocarbon retention plant ( 22 ), the engine ( 10 ) Combusting fuel, the method comprising: during an engine start: selectively routing exhaust gases from the engine to the hydrocarbon retention system (10); 22 ) for storing hydrocarbons of the exhaust gas and operating with spark advance near a peak torque control time; and selectively purging stored hydrocarbons from the hydrocarbon retention plant ( 22 ) to the engine intake ( 23 ). The method of claim 1, further comprising operating at a stoichiometric or rich fuel / air ratio of the exhaust gas during starting, wherein the fuel / air ratio is depleted when one of the Hydrocarbon retention plant ( 22 ) increases the amount of hydrocarbons stored. The method of claim 2, wherein the engine starting includes when the temperature of an emission control device ( 70 ) is below a threshold temperature, the method further comprising, during warm engine restart, passing exhaust gases to an emission control device ( 70 ) and commencing rinsing of the hydrocarbon retention plant ( 22 ). The method of claim 1, further comprising passing exhaust gases to a catalytic emissions control device ( 70 ) in the exhaust gas after the catalytic emission control device ( 70 ) reaches a threshold temperature, as well as the leaning of the fuel / air ratio of the exhaust gas when changing from the passage of exhaust gases to the hydrocarbon retention system ( 22 ) for passing the exhaust gases to the catalytic emission control device ( 70 ). The method of claim 1, wherein termination of the introduction of exhaust gases into the hydrocarbon retention system ( 22 ) is variably controlled to store hydrocarbons depending on at least one fuel property. The method of claim 1, wherein the start of selectively purging the stored hydrocarbons is variably controlled in response to an engine or vehicle operating condition. Method for operating an engine ( 10 ) with an inlet ( 23 ), an outlet ( 25 ) and a hydrocarbon retention plant ( 22 ), the engine ( 10 ) Fuel burns and the outlet burns a catalytic emission control device ( 70 ), wherein the method comprises: during an engine start, when the catalytic emission control device ( 70 ) is below a light-off temperature: in a first mode, the passing of exhaust gases to the hydrocarbon retention system ( 22 and operating during at least a part of the first ignition mode at a first control time and a first fuel / air ratio of the exhaust gas; in a second mode, bypassing the hydrocarbon retention system ( 22 and operating at least a portion of the second ignition mode at a second control time delayed than the first control time or a second exhaust air-fuel ratio leaner than the first exhaust air-fuel ratio , The method of claim 7, wherein the first control time is close to the MBT control time and the first air-fuel ratio is stoichiometric or rich. The method of claim 7, wherein the second mode is performed after the first mode, and wherein the first mode is at a lower temperature of the emissions control device. 70 ) is executed as the second mode. The method of claim 7, wherein the first mode is executed during a first engine start and the second mode is executed during a second engine start. Process according to claim 10, wherein during the second start the hydrocarbon retention plant ( 22 ) has a larger stored amount of hydrocarbons than during the first start. The method of claim 7, wherein in the first mode, the first air-fuel ratio is lean during a first part and is stoichiometric or rich during a second part of the first mode. Process according to claim 7, wherein the hydrocarbon retention plant ( 22 ) a first and second hydrocarbon retention plant ( 22 ), the method further comprising determining degradation of the hydrocarbon retention plant ( 22 ) in response to a fuel / air ratio of the exhaust gas during purging. The method of claim 7, wherein in the first mode at least one cylinder is operating at a lean fuel to air ratio of combustion and at least one cylinder is operating at a rich fuel to air ratio of combustion. Method for operating an engine ( 10 ) with an inlet ( 23 ), an outlet ( 25 ) and a hydrocarbon retention plant ( 22 ), the engine ( 10 ) Combusting fuel, the method comprising: during engine startup: selectively routing exhaust gases from the engine to the hydrocarbon retention system (10); 22 ) for storing exhaust gas hydrocarbons and operating with a rich fuel / air ratio of the exhaust gas; and selectively purging stored hydrocarbons from the hydrocarbon retention plant ( 22 ) to the engine intake. A method according to claim 15, characterized in that, during engine starting, the ignition timing is substantially at the MBT Control time is, even if the catalyst temperature is below a light-off temperature.

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