WO2021037393A1

WO2021037393A1 - Evaporative emissions fuel tank venting system control

Info

Publication number: WO2021037393A1
Application number: PCT/EP2020/025383
Authority: WO
Inventors: Nikhil NAHAR; Vaughn K. Mills; Jeffrey B. Smith; Sascha Hermann; Markus Fritz; Ramita Suteekarn
Original assignee: Eaton Intelligent Power Limited
Priority date: 2019-08-23
Filing date: 2020-08-21
Publication date: 2021-03-04

Abstract

A vent shut-off assembly configured to manage venting on a fuel tank configured to deliver fuel to an internal combustion engine includes a first liquid vapor discriminator (LVD), a main housing, a poppet valve assembly, an actuator assembly and a controller. The actuator assembly includes a cam shaft that includes a first cam. The first cam has a profile that one of opens and closes a poppet valve fluidly coupled to the first LVD. When the poppet valve is in a closed position, vapor is precluded from passing to a carbon canister. When the poppet valve is in an open position, vapor is permitted from passing to the carbon canister. The controller closes the poppet valve at a tank pressure that corresponds to a maximum fill level during a refueling event. The maximum fill level is modified by an input to the controller.

Description

EVAPORATIVE EMISSIONS FUEL TANK VENTING SYSTEM CONTROL

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to Indian Provisional Application No. 201911034069 filed August 23, 2019 and U.S. Provisional Application No. 62/990,106 filed on March 16, 2020. The disclosures of the above applications are incorporated herein by reference.

FIELD

[0002] The present disclosure relates generally to fuel tanks on passenger vehicles and more particularly to a fuel tank having an electronically controlled module that manages the complete evaporative system for the vehicle, the fuel tank venting system having a cam operated venting system and over pressure relief.

BACKGROUND

[0003] Fuel vapor emission control systems are becoming increasingly more complex, in large part in order to comply with environmental and safety regulations imposed on manufacturers of gasoline powered vehicles. Along with the ensuing overall system complexity, complexity of individual components within the system has also increased. Certain regulations affecting the gasoline-powered vehicle industry require that fuel vapor emission from a fuel tank’s ventilation system be stored during periods of an engine’s operation. In order for the overall vapor emission control system to continue to function for its intended purpose, periodic purging of stored hydrocarbon vapors is necessary during operation of the vehicle. In fuel tanks configured for use with a hybrid powertrain it is also necessary to properly vent the fuel tank. Such fuel tanks need to account for high pressures and can incorporate an over pressure relief (OPR) and over vacuum relief (OVR). Moreover, it may also be necessary to provide a means for OVR in a conventional gasoline fuel tank system.

[0004] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0005] A vent shut-off assembly configured to manage venting on a fuel tank configured to deliver fuel to an internal combustion engine includes a first liquid vapor discriminator (LVD), a main housing, a poppet valve assembly, an actuator assembly and a controller. The first LVD is disposed in the fuel tank. The main housing selectively vents to a carbon canister. The poppet valve assembly has a poppet valve arranged in the main housing. The actuator assembly is at least partially housed in the main housing and includes a cam assembly having a cam shaft that includes a first cam. The first cam has a profile that one of opens and closes the poppet valve fluidly coupled to the first LVD, wherein when the poppet valve is in a closed position, vapor is precluded from passing from the fuel tank to the carbon canister. When the poppet valve is in an open position, vapor is permitted from passing from the fuel tank to the carbon canister. The controller closes the poppet valve at a tank pressure that corresponds to a maximum fill level during a refueling event. The maximum fill level is modified by an input to the controller.

[0006] According to other features the input can be wirelessly received by the controller. The input can be communicated by at least one of Bluetooth, WIFI and on board vehicle diagnostic system. The input can be provided by one of an end customer, original equipment manufacturer, fuel system manufacturer, rental car company and car share service. The input can comprise an algorithm that redefines a full fuel tank capacity from a first predetermined fuel tank volume value to a new second predefined fuel tank volume. In another example, the input can be received manually by way of a wired diagnostic tool.

[0007] According to additional features, the vent shut-off assembly further includes a second LVD disposed in the fuel tank. A first vapor tube can be fluidly connected between the first LVD and the main housing. A second vapor tube can be fluidly connected between the second LVD and the main housing. The main housing can include a vent line port. The first and second vapor tubes can be fluidly coupled to the vent line port. In one example, the first and second vapor tube can merge at a union. The main housing can include a canister line port that is fluidly connected to the carbon canister. The actuator assembly can further include a motor that selectively rotates the cam assembly based on operating conditions. The cam assembly can further include a second cam that selectively engages a pump causing the pump to pump liquid fuel out of the housing. The first cam can include a cam surface having a generally high lift surface and a low lift surface. The poppet valve assembly includes a first poppet, a carrier that supports the first poppet and a disk that supports a seal member and a pin that selectively engages the first cam.

[0008] In other features, the poppet valve assembly includes a first biasing member biased between the first poppet and the carrier. A second biasing member is biased between the disk and the retainer. A third biasing member is biased between the retainer and the collar fixed to the pin. The vent shut-off assembly operates during normal operation between a fully open position and a fully closed position. In the fully open position the first cam rotates to a position wherein the high lift surface urges the pin to be depressed causing the first poppet to be lifted off of sealing engagement with an inner lip seal of the seal member. In the fully closed position, the first cam rotates to a position wherein the low lift surface is aligned with the pin wherein the third biasing member urges the pin to retract away from the first poppet and attains a sealing engagement with the inner lip seal of the seal member.

[0009] According to other features, the vent shut-off assembly operates during an over pressure relief (OPR) event wherein pressure within the fuel tank is great enough to cause the seal member to be lifted off of a sealed position with the carrier allowing vapor to pass from the fuel tank to the carbon canister. The vent shut-off assembly can operate during an over vacuum relief (OVR) event wherein pressure within the fuel tank has dropped low enough to cause a vacuum wherein the first poppet is lifted off of a sealing engagement with the inner lip seal of the seal member allowing vapor to pass into the fuel tank.

[0010] A method of refueling a fuel tank having a vent shut-off assembly includes providing the vent shut-off assembly having a first liquid vapor discriminator (LVD), a main housing, a poppet valve assembly, an actuator assembly and a controller. The first LVD is disposed in the fuel tank. The main housing selectively vents to a carbon canister. The poppet valve assembly has a poppet valve arranged in the main housing. The actuator assembly is at least partially housed in the main housing and includes a cam assembly having a cam shaft that includes a first cam. The first cam has a profile that one of opens and closes the poppet valve fluidly coupled to the first LVD, wherein when the poppet valve is in a closed position, vapor is precluded from passing from the fuel tank to the carbon canister. When the poppet valve is in an open position, vapor is permitted from passing from the fuel tank to the carbon canister. The controller closes the poppet valve at a tank pressure that corresponds to a maximum fill level during a refueling event. The controller closes the poppet valve at a tank pressure that corresponds to a predetermined maximum fill level during a refueling event. An input is received by the controller that corresponds to a desired new predetermined fuel tank volume. The predetermined maximum fill level of the fuel tank is modified from the predetermined maximum fill level to an updated predetermined maximum fill level based on the input.

[0011] According to additional features, the method includes wirelessly receiving at the controller the input corresponding to the desired new predetermined fuel tank volume. The input can be communicated by at least one of Bluetooth, WIFI, and on-board vehicle diagnostic system. Receiving the input can comprise receiving the input by one of an end customer, original equipment manufacturer, rental car company and car share service. Receiving the input can include receiving an algorithm that modifies the predetermined maximum fill level of the fuel tank. In other examples, the input can be communicated by a wired diagnostic tool.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0013] FIG. 1 is a schematic illustration of a fuel tank system having an evaporative emissions control system including a vent shut-off assembly, a controller, an electrical connector and associated wiring in accordance to one example of the present disclosure; [0014] FIG. 2 is a front perspective view of an evaporative emissions control system including a vent shut-off assembly configured with solenoids according to one example of the present disclosure;

[0015] FIG. 3 is an exploded view of the evaporative emissions control system of FIG.

2;

[0016] FIG. 4A is a table illustrating operating conditions for the poppet valve assembly shown in FIG. 4B;

[0017] FIG. 4B is a cross-sectional view of the poppet assembly during the conditions shown in FIG. 4A;

[0018] FIG. 5A is a table illustrating operating conditions for the poppet valve assembly shown in FIG. 5B;

[0019] FIG. 5B is a cross-sectional view of the poppet assembly during the conditions shown in FIG. 5A;

[0020] FIG. 6A is a table illustrating operating conditions for the poppet valve assembly shown in FIG. 6B;

[0021] FIG. 6B is a cross-sectional view of the poppet assembly during the conditions shown in FIG. 6A;

[0022] FIG. 7A is a table illustrating operating conditions for the poppet valve assembly shown in FIG. 7B;

[0023] FIG. 7B is a cross-sectional view of the poppet assembly during the conditions shown in FIG. 7A;

[0024] FIG. 8A is a first cross-sectional view of the poppet assembly during the conditions shown in FIGS 4A and 4B;

[0025] FIG. 8B is a second cross-sectional view of the poppet assembly during the conditions shown in FIGS 4A and 4B;

[0026] FIG. 9A is a first cross-sectional view of the poppet assembly during the conditions shown in FIGS 5A and 5B;

[0027] FIG. 9B is a second cross-sectional view of the poppet assembly during the conditions shown in FIGS 5A and 5B;

[0028] FIG. 10A is a first cross-sectional view of the poppet assembly during the conditions shown in FIGS 6A and 6B; [0029] FIG. 10B is a second cross-sectional view of the poppet assembly during the conditions shown in FIGS 6A and 6B;

[0030] FIG. 11A is a first cross-sectional view of the poppet assembly during the conditions shown in FIGS 7A and 7B;

[0031] FIG. 11 B is a second cross-sectional view of the poppet assembly during the conditions shown in FIGS 7A and 7B;

[0032] FIG. 12A is a cross-sectional view of the vent shut-off assembly taken through a pump and shown with a push pin 118 in an extended position;

[0033] FIG. 12B is a cross-sectional view of the vent shut-off assembly taken through the pump and shown with the push pin 118 in a depressed position;

[0034] FIG. 13A is a perspective view of the pump;

[0035] FIG. 13B is an exploded perspective view of the pump of FIG. 13A;

[0036] FIG. 14A is a bottom view of a vent shut-off assembly constructed in accordance to another example of the present disclosure;

[0037] FIG. 14B is a cross-sectional view of the vent shut-off assembly of FIG. 14A taken along lines 14B-14B;

[0038] FIG. 15A is a front perspective view of the vent shut-off assembly of FIG. 14A;

[0039] FIG. 15B is a cross-sectional view of the vent shut-off assembly of FIG. 15A taken along lines 15B-15B;

[0040] FIG. 15C is a cross-sectional view of the vent shut-off assembly of FIG. 15A taken along lines 15C-15C;

[0041] FIG. 15D is a cross-sectional view of the vent shut-off assembly of FIG. 15A taken along lines 15D-15D;

[0042] FIG. 16 is a cross-sectional view of the vent shut-off assembly of FIG. 15A taken along lines 16-16;

[0043] FIG. 17 is an exploded perspective view of a plunger assembly of the vent shut off assembly of FIG. 14A;

[0044] FIG. 18 is an exploded perspective view of a camshaft assembly of the vent shut-off assembly of FIG. 14A;

[0045] FIG. 19A is a first perspective view of a plunger assembly of the vent shut-off assembly of FIG. 14A; [0046] FIG. 19B is a second perspective view of the plunger assembly of FIG. 19A;

[0047] FIG. 19C is a sectional view of the plunger assembly of FIG. 19A; and

[0048] FIGS. 20A-24 show various control sequences according to various examples of the present disclosure.

DETAILED DESCRIPTION

[0049] With initial reference to FIG. 1 , a fuel tank system constructed in accordance to one example of the present disclosure is shown and generally identified at reference number 10. The fuel tank system 10 can generally include a fuel tank 12 configured as a reservoir for holding fuel to be supplied to an internal combustion engine via a fuel delivery system, which includes a fuel pump 14. The fuel pump 14 can be configured to deliver fuel through a fuel supply line 16 to a vehicle engine. The fuel tank 12 can define a vapor dome 18 generally at an upper portion of the fuel tank 12. An evaporative emissions control system 20 can be configured to recapture and recycle the emitted fuel vapor. As will become appreciated from the following discussion, the evaporative emissions control system 20 provides an electronically controlled module that manages the complete evaporative system for a vehicle.

[0050] The evaporative control system 20 provides a universal design for all regions and all fuels. In this regard, the requirement of unique components needed to satisfy regional regulations may be avoided. Instead, software may be adjusted to satisfy wide ranging applications. In this regard, no unique components need to be revalidated saving time and cost. A common architecture may be used across vehicle lines. Conventional mechanical in-tank valves may be replaced. As discussed herein, the evaporative control system 20 may also be compatible with pressurized systems including those associated with hybrid powertrain vehicles.

[0051] The evaporative emissions control system 20 includes a vent shut-off assembly 22, a manifold assembly 24, a liquid trap 26, a control module 30, a purge canister 32, a first vapor tube or vent line 40, a second vapor tube or vent line 42, a third vapor tube or vent line 43, an electrical connector 44, a fuel delivery module (FDM) flange 46 and a fuel fill level sensor assembly such as a float level sensor assembly 48. The first vapor tube 40 can terminate at a vent opening or liquid vapor discriminating (LVD) valve 41A arranged at a top corner of the fuel tank 12. Similarly, the second vapor tube 42 can terminate at a vent opening or LVD valve 41 B arranged at a top corner of the fuel tank 12. The third vapor tube 43 can terminate at a vent opening or LVD valve 41 C arranged at a top of the fuel tank 12. All of the vent openings 41A-41C can terminate at a vapor dome 18. Each of the LVD valves 41 A, 41 B and 41 C are configured to permit vapor to pass from the vapor space 18 to the vent shut-off assembly 22 while inhibiting liquid fuel from entering and passing into the vent shut-off assembly.

[0052] In one configuration, the first, second and third vapor tubes 40, 42 and 43 can merge at a union 47. From the union 47, a vent line connection 49 connects with vent line port 50 defined on the vent shut-off assembly 22. In other examples, some or all of the vapor tubes 41 , 42 and 43 can have a dedicated input port into the vent shut-off assembly 22. In one example, the manifold assembly 24 can be defined within the vent shut-off assembly 22 downstream of the vent line port 50 (or equivalent porting that accepts the respective vapor tubes 41 , 42 and 43).

[0053] As will become appreciated from the following discussion, the vent shut-off assembly 22 can take many forms. In the examples discussed herein, the vent shut-off assembly 22 has an actuator assembly that is configured as a cam actuated system. However, other configurations suitable to selectively open and close vent line port 50 are contemplated including, but not limited to, other mechanical systems, solenoid systems, hydraulic systems, magnetic systems and combinations thereof.

[0054] The control module 30 can further include or receive inputs from system sensors, collectively referred to at reference 60. The system sensors 60 can include a tank pressure sensor 60A that senses a pressure of the fuel tank 12, a canister pressure sensor 60B that senses a pressure of the canister 32, a temperature sensor 60C that senses a temperature within the fuel tank 12, a tank pressure sensor 60D that senses a pressure in the fuel tank 12 and a vehicle grade sensor and or vehicle accelerometer 60E that measures a grade and/or acceleration of the vehicle. It will be appreciated that while the system sensors 60 are shown as a group, that they may be located all around the fuel tank system 10. The control module 30 can additionally include fill level signal reading processing, fuel pressure driver module functionality and be compatible for two-way communications with a vehicle electronic control module (not specifically shown). [0055] The vent shut-off assembly 22 can be configured to control a flow of fuel vapor between the fuel tank 12 and the purge canister 32. The purge canister 32 is adapted to collect fuel vapor emitted by the fuel tank 12 and to subsequently release the fuel vapor to the engine. The control module 30 can also be configured to regulate the operation of evaporative emissions control system 20 in order to recapture and recycle the emitted fuel vapor. The float level sensor assembly 48 can provide fill level indications to the control module 30. As will become appreciated from the following discussion, the control module 30 can send signals to the vent shut-off assembly 22 based on operating conditions such as provided by the sensors 60 to open and close venting from the fuel tank 12 to the purge canister 32.

[0056] With additional reference to FIGS. 2 and 3, the vent shut-off assembly 22 will be further described. The vent shut-off assembly 22 generally comprises a main housing 70, a top housing 72 having a canister line port 73, a poppet valve assembly 74, a cam assembly 76, a motor 78 and a pump 80. The motor 78 and the cam assembly 76 can collectively define an actuator assembly 81. The main housing 70 and the top housing 72 can collectively define a chamber that includes the manifold assembly 24. The main housing 70 can define a poppet assembly receiving bore 84 and a pump outlet opening 88. The poppet assembly receiving bore 84 leads to the vent line port 50 and receives the poppet valve assembly 74. The pump outlet opening 88 generally mounts the pump 80 and provides an outlet for pumping liquid out of the main housing 70 as will be described in detail herein. A vent line 89 can be fluidly connected between the canister line port 73 of the vent shut-off assembly 22 and the canister 32.

[0057] The cam assembly 76 generally includes a first or poppet cam 90 and a second or pump cam 92. The first and second cams 90, 92 are mounted for rotation with a cam shaft 94. A gear 96 is meshingly engaged with a complementary gear (not shown) extending from the motor 78. In other examples the gear 96 can be directly coupled for rotation with a motor drive shaft. The first cam 90 (see FIG. 8A) generally includes a cam surface 100 having a generally high lift surface 102 and a low lift surface 104. The second cam 92 (FIG. 12A) generally includes lift lobes 112, 114 separated by a valley 116. As will become appreciated herein, movement of the cam 92 causes a push pin 118 extending from the pump 80 to translate along its axis as it slidably negotiates along the cam 92 between the lift lobes 112, 114 and the valley 116 causing the pump 80 to pump liquid fuel out of the main housing 70. The push pin 118 is urged into engagement with the cam 92 by a pin biasing member 119.

[0058] With additional reference now to FIG. 4B, the poppet valve assembly 74 will be further described. The poppet valve assembly 74 includes a poppet 120, a disk 122 that supports a seal member 124, a pin 130, a retainer 132 and a poppet carrier 136. A first biasing member 140 is biased between the poppet 120 and the carrier 136. A second biasing member 144 is biased between the disk 122 and the retainer 132. A third biasing member 146 is biased between the retainer 132 and a collar 150 on the pin 130. In some examples, the third biasing member 146 may be omitted as the first and second biasing members 140 and 144 may perform such function. The seal member 124 includes an inner lip seal 154 and an outer lip seal 156.

[0059] As will become appreciated from the following discussion, the poppet valve assembly 74 will be described as moving between fully open and closed positions for achieving various operating functions. However, the poppet valve assembly 74 and other components (such as the disk 122) can move to attain positons intermediate “fully open” and “fully closed”. In this regard, it may be desirable, based on operating conditions, to vent the fuel tank 12 to the carbon canister 30 a predetermined amount between fully open and fully closed.

[0060] In general, the poppet valve 74 allows the vent shut-off assembly 22 to operate in various states, depending on operating conditions, to allow vapor to flow along a first path A (from the fuel tank 12 to the carbon canister 32) or a second path B (from the carbon canister 32 to the fuel tank 12). In one operating condition, vapor that enters at least one of the LVD valves 41 A, 41 B, 41 C passes along at least one of the vapor lines 40, 42, 43 and enters the vent shut-off assembly 22. The operating state of the poppet valve 74, as described herein, allows the vapor to pass therethrough and out of the canister line port 73 to the carbon canister 32 (see flow path A, FIG. 2). Flow path A is desirable alleviate high pressure within the vapor space 18 of the fuel tank. Flow path A can also be desirable during a refueling event or other operating conditions that may cause pressure to rise above a threshold. As will become appreciated herein, the poppet valve 74 can be commanded to move (by the controller 30, FIGS. 4A, 4B) to achieve flow path A or, can automatically move to achieve flow path A (over pressure relief condition, FIGS. 6A, 6B). In another operating condition, fresh air is permitted to pass from the carbon canister 32, into the vent shut-off assembly 22. The operating state of the poppet valve 74 allows that fresh air to exit the vent shut-off assembly 22 through the vent line port 50 and backflow into the vapor space 18 through at least one of the LVD valves 41 A, 41 B, 41 C. Flow path B is desirable to alleviate an undesirable vacuum condition within the vapor space 18 of the fuel tank 12.

[0061] With specific reference now to FIGS. 4A, 4B, 8A and 8B the poppet valve assembly 74 is shown during normal operation in a fully open position. Explained further, the first cam 90 is rotated to a position wherein the high lift surface 102 urges the pin 130 to be depressed or translated leftward as viewed in the FIGS. Translation of the pin 130 causes the poppet 120 to be lifted off of sealing engagement with the inner lip seal 154 of the seal member 124 and into the bias of the first biasing member 140. When the poppet 120 is in the open position, the vapor flow is permitted along flow path A into the vent line port 50 and out of the canister port 73. Fuel vapor from the vapor space 18 is caused to be vented to the canister 32.

[0062] With specific reference now to FIGS. 5A, 5B, 9A and 9B the poppet valve assembly 74 is shown during normal operation in a fully closed position. Explained further, the first cam 90 is rotated to a position wherein the low lift surface 104 aligned with the pin 130 such that bias of the first biasing member 140 causes the pin to be translated rightward as viewed in the FIGS. Translation of the pin 130 rightward causes the poppet 120 to attain a sealing engagement with the inner lip seal 154 of the seal member 124. When the poppet 120 is in the closed position, the vapor flow is inhibited from flowing into the vent line port 50 and out of the canister port 73. Fuel vapor from the vapor space 18 is precluded from venting to the canister 32. Flow along either of flow paths A or B is inhibited.

[0063] With reference now to FIGS. 6A, 6B, 10A and 10B, the poppet valve assembly 74 is shown during an over pressure relief (OPR) condition. In an OPR condition, pressure within the vapor space 18 of the fuel tank 18 has exceeded a threshold wherein vapor pressure in the fuel tank 12 is great enough to cause the seal member 124 to be lifted off of a sealed position with the carrier 136. In one example, the threshold can be around 14kPa for a conventional fuel vehicle and around 37kPa for a pressurized/hybrid vehicle. Explained further, the seal member 124 is caused to translate rightward as viewed in the FIGS such that the outer lip seal 156 moves off of a sealed relationship with the carrier 136. The outer lip seal 156 acts as an OPR seal. In the OPR condition, fuel vapor from the vapor space 18 is caused to flow along flow path A and be vented to the canister 32. Notably, the seal member 124 can move rightward in an OPR condition without any command from the controller 30.

[0064] With reference now to FIGS. 7A, 7B, 11 A and 11 B, the poppet valve assembly 74 is shown during an over vacuum relief (OVR) condition. In an OVR condition, pressure within the vapor space 18 of the fuel tank 18 has dropped below a threshold wherein vapor pressure in the fuel tank is low enough to cause a vacuum wherein the poppet 120 is lifted off of sealing engagement with the inner lip seal 154 of the seal member 124 and into the bias of the first biasing member 140. When the poppet 120 is in the open position, the vapor flow is permitted to equalize pressures. In other words, vapor is permitted to flow along flow path B (from the canister 32 through the canister line 89) out of the vent line port 50 and into the vapor space 18. Notably, the poppet 120 can move leftward in an OVR condition without any command from the controller 30.

[0065] With reference now to FIGS. 12A - FIG. 14, the pump 80 will be further described. The pump 80 is configured to pump liquid fluid out of the vent shut off assembly 22. As will become appreciated, rotation of the cam assembly 76 (FIG. 3) ultimately actuates the pump 80. The pump 80 generally includes a piston housing 210, a piston 212, a check valve 220, a check valve housing 222 and a cap 226. The push pin 118 extends through a spring cap 230, a pump spring 232 and a bearing assembly 240 having bearings 242 and 244.

[0066] The push pin 118 further extends into the piston housing 210 and is coupled to the piston 212. In particular, the push pin 118 defines an annular recess 250 that receives a snap ring 252 thereat. The snap ring 252 can be inserted through a window 258 defined in the piston 212 to engage the push pin 118. The push pin 118 therefore engages the cam 92 on a first end and is fixed for translation with the piston on a second end. A seal 260 is received around an annular surface of the piston 212. The seal 260 slidably translates along an inner diameter 264 (FIG. 12A) of the piston housing 210 during pumping. An umbrella seal assembly 270 having an outer seal member 272 and an inner seal member 274 is disposed on an outboard end of the piston 212.

[0067] The piston housing 210 defines a housing window 266. The housing window 266 allows liquid fuel to enter the piston housing 210 where it can be pumped out of the vent shut off assembly 22. The window 266 can also be used to gain access to the pin 118 when assembling the snap ring 252 at the annular recess 250.

[0068] The check valve 220 can cooperate with the check valve housing 222 and the cap 224 to permit liquid fuel from exiting the check valve housing 222 (out of the vent shut off assembly 22) while inhibiting liquid fuel from entering the vent shut off assembly 22 (through the check valve housing 222). The check valve 220 can take many forms for accomplishing one way fluid flow. In this regard, the specific geometry shown in the FIGS is merely exemplary and other check valves may be used within the scope of this disclosure.

[0069] Operation of the pump 80 will now be described according to one exemplary method of operation. When the lift lobes 112 and 114 of the second cam 92 are aligned with the push pin 118 of the pump 80, fluid that may have passed through the LVD valves 41 A, 41 B and 41 C, to be pumped out of the housing 70. When the valley 116 is aligned with the push pin 118, the biasing member 232 urges the push pin 118 to retract. When the push pin moves from the location shown in FIG. 12A to the position shown in FIG. 12B, liquid fuel in the piston housing 210 is urged by the piston 212 to be expelled into the check valve housing 222 where the check valve 220 permits the liquid fuel to exit the check valve housing 222 and ultimately the vent shut off assembly 22. The pump 80 can be a piston pump or any pump suitable to pump liquid fuel out of the vent shut off assembly 22. By way of example only, the pump can be configured to pump 1-3 cubic centimeters of liquid fuel per cycle and have a maximum pump rate of around 8.3 cubic centimeters per minute.

[0070] As identified above, the evaporative emissions control system 20 can replace conventional fuel tank systems that require mechanical components including in-tank valves with an electronically controlled module that manages the complete evaporative system for a vehicle. In this regard, some components that may be eliminated using the evaporative emissions control system 20 of the instant disclosure can include in-tank valves such as GW’s and FLVV’s, canister vent valve solenoid and associated wiring, tank pressure sensors and associated wiring, fuel pump driver module and associated wiring, fuel pump module electrical connector and associated wiring, and vapor management valve(s) (system dependent). These eliminated components are replaced by the control module 30, vent shut-off assembly 22, manifold 24, and associated electrical connector 44. Various other components may be modified to accommodate the evaporative emissions control system 20 including the fuel tank 12. For example, the fuel tank 12 may be modified to eliminate valves and internal lines to pick-up points. The flange of the FDM 46 may be modified to accommodate other components such as the control module 30 and/or the electrical connector 44. In other configurations, the fresh air line of the canister 32 and a dust box may be modified. In one example, the fresh air line of the canister 32 and the dust box may be connected to the control module 30. [0071] Turning now to FIGS. 14A-15A and 18, a vent shut-off assembly constructed in accordance to additional features of the present disclosure is shown and generally identified at reference 522. As will become appreciated from the following discussion, the vent shut off assembly 522 can be configured for use with a fuel tank for a hybrid vehicle. A fuel tank system for a hybrid vehicle can include a fuel tank isolation valve (FTIV) that includes built in OPR and OVR. The vent shut-off assembly 522 according to the present disclosure incorporates OPR and OVR. In this regard, the vent shut-off assembly 522 can be used on fuel tanks configured for use with hybrid powertrains. As will become appreciated from the following discussion, the vent shut-off assembly 522 is similar to the vent shut-off assembly 22 however the vent shut-off assembly 522 has dedicated cams and poppets for each of the LVD valves 41 A, 41 B and 41 C.

[0072] The vent shut-off assembly 522 includes a main housing 502 that at least partially houses an actuator assembly 510. A canister vent line (not shown but see canister vent line 89, FIG. 1) routs to the canister (see canister 32, FIG. 1). The vent shut-off assembly 522 includes a cam assembly 530. The cam assembly 530 includes a cam shaft 532 that includes cams 534, 536 and 538. The cam shaft 532 is rotatably driven by a motor 540 and can be supported in the housing 502 on opposite ends by grommets 542 (FIG. 18). In the example shown the motor 540 is received in the housing 502. The motor 540 is a direct current motor that directly drives the camshaft 532. Other configurations are contemplated. The cams 534, 536 and 538 rotate to interact with respective plunger assemblies (or poppet valve assemblies) 544, 546 and 548 to open and close valves 554, 556 and 558, respectively. The valves 554, 556 and 558 open and close to selectively deliver vapor through ports 564, 566 and 568, respectively. In one example the motor 540 can alternately be a stepper motor. An active drain liquid trap (ADLT) 570 can be provided on the housing 502.

[0073] As will be described herein, each of the plunger assemblies 544, 546 and 548 are configured as poppet valves with spring return. With spring return, these plunger assemblies 544, 564 and 548 provide a pressure relief function. In other words, if a pressure experienced on one side of the poppet valve is large enough to overcome a bias of an oppositely acting spring, the valve will open to relieve the pressure.

[0074] With reference now to FIG. 17, a plunger assembly 544 is shown in exploded view. Description of the plunger assembly 544 will now be explained with the understanding that the plunger assemblies 546 and 548 are similarly constructed. The plunger assembly 544 includes a stem assembly 600, a roller 606, an O-ring 610, a plunger housing 620, a first biasing member 624 and a collar 630. The stem assembly 600 can include a seal 632 disposed around a stem body 634.

[0075] As shown in FIGS. 19A-19C, the plunger sub-assembly 544 can also include an OPR check valve 640. The OPR check valve 640 can include a ball 644, a second biasing member 646 and a disk 648. During operation, the seal 632 of the plunger assembly 544 is normally sealed against a seat 652 on the plunger housing 620. No vapor can pass through plunger assembly 544 in the sealed position. The first biasing member 624 will urge the collar 630 upward (as viewed from FIG. 19C) urging the stem body 634 upward and the seal 632 against the seat 652. It is appreciated that the first biasing member 624 is permitted to urge the collar 630 when the cam 534 is not urging the roller 606 downward. In other words, the cam 534 is sufficiently in a no lift position. If enough pressure builds against an upper surface (as viewed in FIG. 19C) of the collar 630 to overcome the bias of the first biasing member 624, the plunger assembly 544 can open by moving the stem assembly 600 downward and urging the seal 632 off of the seat 652. [0076] If a predetermined pressure is reached in the vapor dome within the fuel tank (see fuel tank 12, FIG. 1), the OPR check valve 640 will open. Specifically, the ball 644 will urge the second biasing member 646 upward. As the ball 644 moves upward, the ball 644 moves off of a ball seat 664 on the stem body 634 allowing fuel vapor to be relieved from the vapor dome of the fuel tank through passages 660 (FIG. 19B) of the stem body 634, around the ball 644 and through a corresponding passage 670 (FIG. 19C) in the disk 648. The passages 660 can be formed anywhere on the stem body 634. In sum, the plunger assembly 544 can incorporate an OPR/OVR relief function in both directions to relieve pressure on opposite ends of the plunger assembly 544. In other advantages, the OPR/OVR relief function is mechanically operable independent of power supply. In this regard, the OPR/OVR relief will work subsequent to power loss in the vehicle.

[0077] In some examples, the OPR check valve functionality can be incorporated on only the plunger assembly 544. In other examples, an OPR check valve can be additionally or alternatively incorporated on the plunger assemblies 546 and 548. In other arrangements the OPR/OVR functionality can be incorporated elsewhere on the vent shut-off assembly 522 such as through the housing 502. In yet other configurations, the OPR/OVR mechanism can be provided as a snorkel out of the housing 502. The snorkel can be routed to the center of the fuel tank and most likely to always see vapor. In another configuration, the OPR/OVR mechanism can be incorporated into a vapor line leaving the fuel tank downstream of the in-line liquid vapor discriminating (LVD) valve that is part of the vent shut-off assembly 522. The OPR/OVR can also be incorporated into the LVD that is part of the vent shut-off assembly 522. The OPR/OVR can be incorporated at the exit of the ADLT 570. As explained above, the vent shut-off assembly 522 provides an OVR function at each of the plunger assemblies 544, 546 and 548.

[0078] FIGS. 20A-24 show various control sequences according to various examples of the present disclosure. FIGS. 20A and 20B show exemplary methods for transferring liquid fuel in the liquid trap 26 back to the fuel tank 12. Further, vapor can be pumped to the fuel tank 12 to pressurize the fuel tank 12 for OBD leak test. Once the liquid trap 26 is drained, the pump 80 can be commanded over CAN to pump vapor into the fuel tank 12. The control module 30 can further provide a second level of functionality using operation of poppet valve 74. In this regard, liquid can be separated from vapor under dynamic conditions or static conditions. Liquid can be separated from vapor in the liquid trap 26. Liquid can be inhibited from exiting the fuel tank 12 by keeping the liquid trap 26 drained. Such functionality is particularly advantageous during roll over.

[0079] The control method shown in FIGS. 20A-20B is generally identified at reference 700. At 710 the controller 30 reads various inputs from the sensors 60. At step 712 the controller 30 processes raw inputs and converts them to physical values. In one non limiting example, the controller 30 can use gain and offset values or DBC file. At step 716, control compares accelerations in the longitudinal and lateral directions against thresholds. Such comparisons may be made in a look-up table. At step 720, control assigns a rate of liquid carryover from the LVD’s 41A-41C to the liquid trap 26. At step 722 a liquid trap fill rate and drain rate is added to determine liquid trap level change. If the liquid trap 26 is activated, the drain rate is passed onto the controller 30 at step 730. At step 734 control integrates over time to calculate an estimated liquid trap level and compares the level against an upper and lower hysteresis threshold.

[0080] If control determines that the level of liquid in the liquid trap 26 is greater than an upper threshold at step 740, control activates the pump 80 at step 744. If the level of liquid in the liquid trap 26 is not greater than an upper threshold, control determines whether the level of liquid in the liquid trap 26 is less than a lower threshold at step 750. If control determines that the level of liquid in the liquid trap 26 is less than a lower threshold, control deactivates the pump 80 at step 754. The state of the pump 80 is maintained at step 760. At step 770 a vehicle controller area network (CAN) command operates the pump 80. It is appreciated that the liquid level in the liquid trap 26 will take precedent over a CAN command at step 780. If control determines that the pump 80 is running continuously (for example 5 minutes), the controller 30 stops the pump 80 for a period of time (for example 2 minutes) for over-heat protection at step 782.

[0081] FIGS. 21 A and 21 B show additional control methods according to examples of the present disclosure. In this regard, evaporative vapor can be transferred to the engine to purge. Variable controlled orifice venting can be achieved. Vapor can freely vent to and from the fuel tank 12 during normal venting. Vapor can freely vent from the fuel tank 12 during depressurization such as for a plug in hybrid / electrical vehicle (PHEV). Pressure can be controlled in a certain level (mild hybrid). The fuel tank 12 can be isolated during a canister purge event. The fuel tank 12 can be isolated during a non refueling and non-purge event. The fuel tank 12 can be isolated to vent the fuel system for OBD leak test. Liquid fuel can be inhibited from exiting the fuel tank during a roll over event.

[0082] The control method shown in FIGS. 21 A-21 B is generally identified at reference 800. At step 812 control acquires vehicle data from the sensors 60 related to static and dynamic properties of the vehicle. At step 814, control determines whether the vehicle is at rest. If the vehicle is at rest, control determines whether the fuel level is less than 100% full at step 818. As will be appreciated herein, the control methods of the present disclosure will allow this step 818 to take many forms. If control determines that the vehicle is not at rest, control determines whether the vehicle is in a roll-over state at step 820. If the vehicle is in a roll-over state, the valve 74 is closed at step 824. If the vehicle is not in a roll-over state, control opens the vent valve 74 a predetermined amount such as full or limited flow at step 830. At step 832 control closes the valve 74 if the tank pressure is less than the lower pressure threshold. Similarly, at step 832, control opens the valve 74 partially if the tank pressure is greater than the upper pressure threshold. In some examples, the lower threshold can be 3 kpa and the upper threshold can be 4 kpa. In some examples, the controller can open the valve 74 to a very small equivalent orifice size (such as 2 mm) to mimic conventional GVV/ROV venting. At step 840, control determines if the system is in a pressurized mode from a CAN command. At 840, control further determines for a pressurized system OPR and OVR open and close thresholds. At 844 control opens the valve 74 if tank pressure is greater than an OPR open threshold or if a tank pressure is less than an OVR open threshold. At 844 control further closes the vent 74 if the tank pressure is less than an OPR close threshold or if a tank pressure is greater than an OVR close threshold. At step 850 control determines whether the vehicle fuel system is in pressurized mode. If in pressurized mode, control proceeds to step 844. If not in pressurized mode, control proceeds to step 854.

[0083] According to additional features of the instant application, a method of upgrading the realized volume of the fuel tank 12 is provided. In some prior art arrangements, the maximum fuel volume is limited by mechanical shut off devices. By using a software controlled shut off mechanism as taught herein, it is possible to upgrade (allow for a higher realized) fuel level for customer needs using the same hardware. A software change can be provided over the air, on demand, over a vehicle CAN bus (such as for example at a repair shop) or manufacturing line (original equipment manufacturer or Tier 1 tank supplier). Explained further, in some examples the fuel tank hardware shuts off venting and therefore causes shut-off during fill up even though there may still be some volume of fuel tank 12 empty (available for filling). In some cases, a given fuel tank 12 may have one or two liters of remaining capacity to accept fuel even though venting closes causing fuel fill shut off. By way of non-limiting example, the software implemented by the control module 30 of the fuel tank system 10 can be updated through an input 62 (FIG. 1). The input can be made by the end customer, original equipment manufacturer (OEM), tank manufacturer, fuel system manufacturer prior to delivering to the OEM, car rental or share service, or anyone authorized to make the input.

[0084] As identified above, an input can be an over the air input (Bluetooth, WIFI, on board vehicle diagnostic system, or other wireless input), a manual input (wired diagnostic tool upgrade). The input can be an algorithm that redefines a full fuel tank from a predetermined volume value, for example 52 liters, to a new predefined volume value, for example 55 liters. It will be appreciated by those skilled in the art that the volumes listed are merely exemplary and others may be used. It will be further appreciated that any newly predefined volume value must physically be attainable by the fuel tank 12.

[0085] The present method contemplates the ability to be able to update any software limits related to tank capacity. In this regard, the decision “If Fuel Level < 100” can be updated to change any predefined value of what “100” is. The threshold of fuel level check 100% can be modified using any “input” described above according to a user input maximum fuel level. In other methods, an over the air update can be made by end- customers at any time to have adjustable tank capacity. In one example, an end- customer may wish to make an update (input) to have adjustable tank capacity for expense control plan. In other methods, an over the air update can be made by a ride share or car rental service at any time to offer higher-range vehicles as an add-on option. It is further contemplated that the end user or other person authorized to provide the input may wish to increase the allowed volume fill for any given event or chain of events, for example a long trip or another desire to reduce visits to a fuel filling station (poor weather, family member using vehicle where it is desirable to not unnecessarily burden with refueling).

[0086] It is further contemplated by the methods of the present disclosure that such maximum fill levels set by the controller 30 may be changed based on a volume change period or time based. In this regard, volume may be modified (such as by an input 62 described above) to accommodate more fuel for a long trip. Similarly, volume may be reduced to a nominal level upon conclusion of such trip. Such scenario may be implemented for private use, rental car or car sharing situations. It is contemplated that in a rental car situation this ability would allow a car rental company to charge more for providing “an increased volume” fuel tank. In some examples, the controller 30 includes an actual clock signal (such as provided by a vehicle electronic control unit) having an actual time and date, adjustable by user per location. The controller 30 can have a fixed maximum “total volume” that is a target maximum refilling volume per period of time (e.g., a week). A maximum “refilling volume” can be set for one refueling. An “actual volume” can be an estimated accumulated volume since the beginning of the week. The accumulated volume can be reset upon satisfying a period of time. The controller 30 can define the refilling volume depending on the actual volume as a percentage of total volume and time left until the next controller reset.

[0087] FIGS. 22 and 23 illustrate control methods disclosed by the current Assignee as set forth in U.S. Patent Application Serial No. 15/589,404 filed on May 8, 2017 and entitled “Fuel System Control”, the contents of which are expressly incorporated herein by reference. FIGS. 22 and 23 show an exemplary refuel detection and refuel event including transferring refueling vapor unobstructed to the canister 32. Tank pressure is managed during refueling. A final refueling volume can be managed using trickle fill function.

[0088] With reference to FIGS. 22 and 23, an example method 4100 of controlling an evaporative emissions control system begins at step 4110 where controller 30 monitors fuel level sensor 48, pressure sensor 60a, and accelerometer 60e. At step 4120, controller operates poppet valve 74 based on a determination of whether the vehicle is moving (slosh condition) or parked (parked condition). One example system operation during dynamic operation (slosh condition) is described in commonly owned co-pending U.S. Patent Application Serial No. 15/468,739, the contents of which are incorporated herein by reference.

[0089] At step 4130, controller 30 monitors accelerometer 60e over a predetermined period of time to determine if a delta acceleration is less than a predetermined threshold. At step 4140, controller 30 determines if the vehicle is not moving or is at rest based on the measurements from step 4130. If it is determined the vehicle is not at rest, control returns to step 4120. If it is determined the vehicle is at rest, control proceeds to step 4170.

[0090] At step 4150, controller 30 monitors fuel level sensor 48 over a predetermined period of time to determine if a delta fuel level is greater than a predetermined threshold. At step 4160, controller 30 determines if the fuel level is increasing in the fuel tank 12 based on the measurements from step 4150. If it is determined the fuel level is not rising, control returns to step 4120. If it is determined the fuel level is rising, control proceeds to step 4170.

[0091] At step 4170, controller 30 determines if both the vehicle is at rest and if the fuel level in the fuel tank 12 is increasing. If no, control returns to step 4120. If yes, control proceeds to step 4180 where controller 30 monitors the pressure sensor 60a over a predetermined period of time to determine if a delta pressure is greater than a predetermined threshold. At step 4190, controller 30 determines if the pressure is increasing in the fuel tank 12 based on the measurements from step 4180. If it is determined the tank pressure is not increasing, control proceeds to step 4500 (FIG. 3B) and returns to normal operation. If it is determined the tank pressure is increasing, at step 4200, controller 30 determines a refueling event is occurring and proceeds to step 4210.

[0092] At step 4210, controller 30 opens poppet valve 74. At step 4220, controller 30 monitors fuel level sensor 48. At step 4230, controller 30 determines if the fuel level measured in step 4220 has reached or exceeded a predetermined first shutoff level threshold. If no, at step 4240, controller 30 determines if the vehicle is at rest and if the fuel level is increasing based on measurements from fuel level sensor 48 and accelerometer 60e. If yes, control returns to step 4220. If no, control proceeds to step 4490 and controller 30 determines it is the end of the refueling event. Control then proceeds to step 4500.

[0093] If at step 4230 the controller 30 determines the measured fuel level is greater than the first shutoff level predetermined threshold, control proceeds to step 4250 and controller 30 closes poppet valve 74. This can result in any subsequent refueling increasing the pressure in fuel tank 12, thereby causing a fuel pump nozzle to shut off. [0094] At step 4260, controller 30 determines if the predetermined first shutoff level threshold is a final shutoff (e.g., as determined by a preset condition) such that supplying additional fuel to the fuel tank 12 is undesirable. However, multiple shutoff levels may be desirable, for example, to enable trickle filling of the fuel tank 12. It will be appreciated that the number of threshold levels and their shutoff values may be predetermined by various factors such as manufacturing specifications, desired performance, safety standards, etc.

[0095] If the first shutoff level threshold is the final shutoff level, control proceeds to 4270, and controller 30 subsequently operates poppet valve 74 to maintain pressure in the fuel tank 12 for a predetermined amount of time before signaling the end of the refueling event at step 4490. If it is not the final shut off level, control proceeds to step 4280.

[0096] At step 4280, controller 30 waits for a predetermined time (e.g., 10 seconds) and then proceeds to step 4290 where controller 30 opens poppet valve 74. In one example, the poppet valve 74 is opened a small amount which can allow a limited amount of fuel to subsequently enter fuel tank 4010 without shutting off the fuel pump nozzle. At step 4300, controller 30 monitors the fuel level sensor 48. At step 4310, controller 30 determines if the fuel level measured in step 4300 meets or exceeds a subsequent predetermined shutoff level threshold. For example, the system may include a 2^nd shutoff level threshold and a 3^rd shutoff level threshold. If the increased fuel level exceeds the subsequent fuel shutoff level, control returns to step 4250. If the increased fuel level does not exceed the subsequent fuel shutoff level, control proceeds to step 4320 where the system can return to normal operation.

[0097] At step 4320, the controller 30 determines if the vehicle is at rest and if the fuel level is increasing in the fuel tank 12 based on measurements from fuel level sensor 48 and accelerometer 60e. If yes, control returns to step 4300. If no, control proceeds to step 4490 and signals the end of the refueling event.

[0098] As such, controller 30 includes a fill or refueling algorithm for customization of a trickle fill based on a desired profile. For example, a desired profile can define one or more fuel heights for the predetermined shutoff level threshold(s). The fuel level sensor 48 is utilized to determine the fuel volume in the tank 12 and thus a percent fill. At the desired predetermined fill level, the poppet valve 74 is closed, resulting in a pressure buildup that causes a fuel pump nozzle to shut off. If the desired profile is to allow for trickle fill, the controller 30 subsequently opens the poppet valve 74 after a predetermined time to allow fuel tank filling to resume. Once the next fill level is reached (e.g., 2^nd shutoff level threshold), the controller 30 shuts the poppet valve 74, again resulting in a pressure buildup that causes the fuel pump nozzle to shut off. This can be continued for one or more trickle fills (or “clicks”) as determined in the desired profile.

[0099] In a case where the predetermined time the poppet vale 74 is closed (either in between trickle fills or after the final fill) is sufficiently long to cause the fuel tank pressure to build above a predetermined threshold, controller 30 can “pulse” the poppet valve 74 open and closed via dithering, pulse width modulation, or other method. The allows the fuel tank pressure to remain at or below a predetermined level while also preventing further volume to be added via fill. Such modulation can continue until the vehicle is no longer at rest, or controller 30 receives a signal indicating the refuel event has ended. [00100] Turning now to FIG. 24, a control method for returning the cam assembly 76 to a home position is shown and generally identified at reference 900. As can be appreciated, it is desirable to know the position of the cam assembly 76 (home position) to determine how much to rotate the cam shaft 94 to achieve various degrees of open for the valve assembly 74 and/or actuation of the pump 80.

[00101] In step 910 control determines if the vehicle is in a roll over condition. If control determines that the vehicle is in a roll over condition, the valve assembly 74 is closed and the pump 80 is turned off. At step 912 control performs a homing routing as required. In this regard, the homing routine can include an initial homing routine, a venting open homing routine and a venting closing routine. At step 914 control determines an appropriate stepper motor command and passes it to a stepper driver board that communicates a signal to the motor 78. At step 916 the stepper driver board initializes operation of the motor 78 according to the determined command.

[00102] Exemplary, non-limiting homing routines will now be described. In a first homing routine, the motor 78 is rotated the number of steps equivalent to one full rotation of the cam shaft 94 in the clockwise (or counter-clockwise) direction, or until a motor stall is detected by the controller 30. The number of steps necessary to trigger a motor stall is recorded. The number of steps should be greater than 330 degrees of motion and less than 338 degrees of motion, or approximately a span of the cam lobe 92 around a hardstop. Additional details regarding the hardstop may be found in commonly owned PCT Application entitled “Evaporative Emissions Fuel Tank Venting System With Mechanical Liquid Detection”, PCT/EP2020/025294 filed June 19, 2020 which is expressly incorporated by reference. A true hard stop is confirmed. Additional variations of a homing routine may include multiple combinations of full motion clockwise and counter-clockwise rotations.

[00103] In a second exemplary homing routine, at key off, the last known position of the cam shaft 94 is saved, such as saved in the memory of the controller 30. In subsequent key on, the last known position is retrieved and as per the tank mode (pressurized system), the motor 78 is commanded to rotate a number of steps toward the hard stop from closed venting until a stall is detected. The number of steps will be similar to the steps required from the last known position. A true hard stop is confirmed.

[00104] In a third exemplary homing routine, the motor 78 is rotated the number of steps equivalent to one full rotation of the cam shaft 94 in the clockwise (or counter-clockwise) direction, or until a motor stall is detected by the controller 30. The number of steps necessary to trigger a motor stall is recorded. The number of steps should be greater than 330 degrees of motion and less than 338 degrees of motion, or approximately a span of the cam lobe 92 around a hardstop. The motor 78 is rotated a number of steps equivalent to Anglespan (such as 30 degrees) rotation in the counter-clockwise direction. The motor 78 is rotated the number of steps equivalent to Anglespan plus Deltal degrees (such as 30 degrees + 5 degrees = 35 degrees) rotation in the clockwise direction, or until a motor stall is detected by the controller 30. The number of steps when stall is detected should be greater than for Anglespan minus Delta2 degrees (such as 30 degrees - 2 degrees = 28 degrees) motion and less than Anglespan plus Deltal degrees (such as 30 degrees + 5 degrees = 35 degrees) motion (approximately a span of the cam lobe 92 around the hardstop). This confirms a true hardstop.

[00105] In a fourth exemplary homing routine, the motor 78 is rotated a number of step equivalent to one full cam shaft rotation in the clockwise direction. The motor 78 is then rotated a number of steps equivalent to one full cam shaft rotation in the counter clockwise direction. The motor 78 is then rotated a number of steps equivalent to one full cam shaft rotation in the clockwise direction. The motor 78 is then rotated a number of steps equivalent to one full cam shaft rotation in the counter-clockwise direction.

[00106] Described herein are systems and methods for controlling electronically controlled vent valves during a vehicle refueling event. The system monitors a vehicle accelerometer, a fuel tank level sensor, and a fuel tank pressure sensor to determine if the vehicle is undergoing a refueling event. The system then automatically closes the vent valves once the fuel level exceeds a predetermined shutoff level. Moreover, the system may include additional shutoff levels that that enable additional refueling. The valve closings cause the fuel tank pressure to increase, which causes a fuel pump nozzle to shut off the supply of fuel to the fuel tank. This prevents liquid fuel from passing the vent valves and reaching other parts of the fuel tank system. Accordingly, rather than relying on vent valves that only provide passive responses to detected liquid fuel, the described control strategy enables predictive control to prevent liquid fuel from leaving the fuel tank.

[00107] The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1. A vent shut-off assembly configured to manage venting on a fuel tank configured to deliver fuel to an internal combustion engine, the vent shut-off assembly comprising: a first liquid vapor discriminator (LVD) disposed in the fuel tank; a main housing that selectively vents to a carbon canister; a poppet valve assembly having a poppet valve arranged in the main housing; an actuator assembly at least partially housed in the main housing, the actuator assembly comprising: a cam assembly having a cam shaft that includes a first cam having a profile that one of opens and closes the poppet valve fluidly coupled to the first LVD, wherein when the poppet valve is in a closed position, vapor is precluded from passing from the fuel tank to the carbon canister and wherein when the poppet valve is in an open position, vapor is permitted from passing from the fuel tank to the carbon canister; and a controller that closes the poppet valve at a tank pressure that corresponds to a maximum fill level during a refueling event, wherein the maximum fill level is modified by an input to the controller.

2. The vent shut-off assembly of claim 1 wherein the input is wirelessly received by the controller.

3. The vent shut-off assembly of claim 2 wherein the input is communicated by at least one of Bluetooth, WIFI, and on-board vehicle diagnostic system.

4. The vent shut-off assembly of claim 3 wherein the input is provided by one of an end customer, original equipment manufacturer, fuel system manufacturer, rental car company, and car share service.

5. The vent shut-off assembly of claim 1 wherein the input comprises an algorithm that redefines a full fuel tank capacity from a first predefined fuel tank volume value to a new second predefined fuel tank volume.

6. The vent shut-off assembly of claim 1 wherein the input is received manually by way of a wired diagnostic tool.

7. The vent shut-off assembly of claim 1 , further comprising: a second LVD disposed in the fuel tank.

8. The vent shut-off assembly of claim 7, further comprising: a first vapor tube fluidly connected between the first LVD and the main housing; and a second vapor tube fluidly connected between the second LVD and the main housing.

9. The vent shut-off assembly of claim 8 wherein the main housing includes a vent line port, wherein the first and second vapor tubes are fluidly coupled to the vent line port.

10. The vent shut-off assembly of claim 9, further comprising a union wherein the first and second vapor tubes merge thereat.

11. The vent shut-off assembly of claim 1 wherein the main housing includes a canister line port that is fluidly connected to the carbon canister.

12. The vent shut-off assembly of claim 1 wherein the actuator assembly further includes a motor that selectively rotates the cam assembly based on operating conditions.

13. The vent shut-off assembly of claim 1 , wherein the cam assembly further includes a second cam that selectively engages a pump causing the pump to pump liquid fuel out of the main housing.

14. The vent shut-off assembly of claim 1 wherein the first cam generally includes a cam surface having a generally high lift surface and a low lift surface.

15. The vent shut-off assembly of claim 14 wherein the poppet valve assembly includes a first poppet, a carrier that supports the first poppet, a disk that supports a seal member and a pin that selectively engages the first cam.

16. The vent shut-off assembly of claim 15 wherein the poppet valve assembly further comprises: a first biasing member biased between the first poppet and the carrier; a second biasing member biased between the disk and the retainer; and a third biasing member biased between the retainer and the collar fixed to the pin.

17. The vent shut-off assembly of claim 16 wherein the vent shut-off assembly operates during normal operation between: a fully open position wherein the first cam rotates to a position wherein the high lift surface urges the pin to be depressed causing the first poppet to be lifted off of sealing engagement with an inner lip seal of the seal member; and a fully closed position wherein the first cam rotates to a position wherein the low lift surface is aligned with the pin wherein the third biasing member urges the pin to retract away from the first poppet and attains a sealing engagement with the inner lip seal of the seal member.

18. The vent shut-off assembly of claim 17 wherein the vent shut-off assembly operates during an over pressure relief (OPR) event wherein pressure within the fuel tank is great enough to cause the seal member to be lifted off of a sealed position with the carrier allowing vapor to pass from the fuel tank to the carbon canister.

19. The vent shut-off assembly of claim 18 wherein the vent shut-off assembly operates during an over vacuum relief (OVR) event wherein pressure within the fuel tank has dropped low enough to cause a vacuum wherein the first poppet is lifted off of a sealing engagement with the inner lip seal of the seal member allowing vapor to pass into the fuel tank.

20. A method of refueling a fuel tank having a vent shut-off assembly, the method comprising: providing the vent shut-off assembly having: a first liquid vapor discriminator (LVD) disposed in the fuel tank; a main housing that selectively vents to a carbon canister; a poppet valve assembly having a poppet valve arranged in the main housing; an actuator assembly at least partially housed in the main housing, the actuator assembly comprising: a cam assembly having a cam shaft that includes a first cam having a profile that one of opens and closes the poppet valve fluidly coupled to the first LVD, wherein when the poppet valve is in a closed position, vapor is precluded from passing from the fuel tank to the carbon canister and wherein when the poppet valve is in an open position, vapor is permitted from passing from the fuel tank to the carbon canister; and a controller that closes the poppet valve at a tank pressure that corresponds to a predetermined maximum fill level during a refueling event; receiving, at the controller, an input corresponding to a desired new predetermined fuel tank volume; modifying the predetermined maximum fill level of the fuel tank from the predetermined maximum fill level to an updated predetermined maximum fill level based on the input.

21. The method of claim 20 wherein modifying the predetermined maximum fill level comprises: receiving, wirelessly at the controller the input corresponding to the desired new predetermined fuel tank volume.

22. The method of claim 21 wherein the input is communicated by at least one of Bluetooth, WIFI, and on-board vehicle diagnostic system.

23. The method of claim 20 wherein receiving the input comprises receiving the input by one of an end customer, original equipment manufacturer, rental car company and car share service.

24. The method of claim 20 wherein receiving the input comprises receiving an algorithm that modifies the predetermined maximum fill level of the fuel tank.

25. The method of claim 20 wherein the input is communicated by a wired diagnostic tool.