Variable restriction fuel vapor canister
First Claim
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1. A system for an engine with a fuel vapor recovery system, comprising:
- a fuel vapor canister;
a restriction valve disposed in a purge flow path between storage material in the fuel vapor canister;
an atmosphere vent coupled to the fuel vapor canister and a vent valve disposed therein;
a purge conduit coupled to the fuel vapor canister and an intake of the engine;
a sensor arranged in the purge conduit; and
a controller configured to;
initiate a fuel vapor purging event, including adjusting a duty-cycle of a pump in the purge conduit to provide a first amount of vacuum to the fuel vapor canister and adjusting the restriction valve to provide a first amount of flow restriction between the storage material in the fuel vapor canister;
determine, based on input from the sensor, an amount of fuel vapor purged from the fuel vapor canister;
if the amount of fuel vapor purged from the fuel vapor canister is less than a first threshold, adjust the duty-cycle of the pump to increase an amount of vacuum provided to the fuel vapor canister to a second, higher amount of vacuum while maintaining the first amount of flow restriction between the storage material in the fuel vapor canister; and
after adjusting the duty-cycle of the pump, determine, based on input from the sensor, the amount of fuel vapor purged from the fuel vapor canister, and if the amount of fuel vapor purged from the fuel vapor canister is less than a second threshold, adjust the restriction valve to increase the amount of flow restriction between the storage material in the fuel vapor canister from the first amount to a second, higher amount while maintaining the duty-cycle of the pump to continue providing the second amount of vacuum to the fuel vapor canister.
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Abstract
Systems and methods for operating an engine with a fuel vapor recovery system are disclosed. In one example approach, a method for an engine with a fuel vapor recovery system comprises increasing an amount of flow restriction between storage material in a fuel vapor canister while maintaining a vent valve open during a fuel vapor purging event.
28 Citations
19 Claims
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1. A system for an engine with a fuel vapor recovery system, comprising:
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a fuel vapor canister; a restriction valve disposed in a purge flow path between storage material in the fuel vapor canister; an atmosphere vent coupled to the fuel vapor canister and a vent valve disposed therein; a purge conduit coupled to the fuel vapor canister and an intake of the engine; a sensor arranged in the purge conduit; and a controller configured to; initiate a fuel vapor purging event, including adjusting a duty-cycle of a pump in the purge conduit to provide a first amount of vacuum to the fuel vapor canister and adjusting the restriction valve to provide a first amount of flow restriction between the storage material in the fuel vapor canister; determine, based on input from the sensor, an amount of fuel vapor purged from the fuel vapor canister; if the amount of fuel vapor purged from the fuel vapor canister is less than a first threshold, adjust the duty-cycle of the pump to increase an amount of vacuum provided to the fuel vapor canister to a second, higher amount of vacuum while maintaining the first amount of flow restriction between the storage material in the fuel vapor canister; and after adjusting the duty-cycle of the pump, determine, based on input from the sensor, the amount of fuel vapor purged from the fuel vapor canister, and if the amount of fuel vapor purged from the fuel vapor canister is less than a second threshold, adjust the restriction valve to increase the amount of flow restriction between the storage material in the fuel vapor canister from the first amount to a second, higher amount while maintaining the duty-cycle of the pump to continue providing the second amount of vacuum to the fuel vapor canister. - View Dependent Claims (2, 3)
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4. A system for an engine with a fuel vapor recovery system, comprising:
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a fuel vapor canister; a restriction valve disposed in a purge flow path between storage material in the fuel vapor canister; an atmosphere vent coupled to the fuel vapor canister and a vent valve disposed therein; a purge conduit coupled to the fuel vapor canister and an intake of the engine and having a purge valve arranged therein; a sensor arranged in the purge conduit; and a controller with instructions programmed therein to; initiate a fuel vapor purging event, the initiation including increasing opening of the purge valve to a first opening amount while maintaining the restriction valve fully open; determine, based on input from the sensor, an amount of fuel vapor purged from the fuel vapor canister; in response to the amount of fuel vapor purged from the fuel vapor canister decreasing below a first threshold, further increase the opening of the purge valve to a second opening amount while maintaining the restriction valve fully open; in response to the amount of fuel vapor purged from the fuel vapor canister decreasing below a second threshold, the second threshold lower than the first threshold, decrease opening of the restriction valve while maintaining the opening of the purge valve at the second opening amount; and maintain the vent valve open throughout a duration of the fuel vapor purging event. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 19)
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13. A system for an engine with a fuel vapor recovery system, comprising:
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a fuel vapor canister; a restriction valve disposed in a purge flow path between storage material in the fuel vapor canister; an atmosphere vent coupled to the fuel vapor canister and a vent valve disposed therein; a purge conduit coupled to the fuel vapor canister and an intake of the engine and having a sensor arranged therein; and a controller with instructions programmed therein to; initiate a fuel vapor purging event; determine, based on input from the sensor, an amount of fuel vapor purged from the fuel vapor canister; adjust the restriction valve to restrict flow between the storage material in the fuel vapor canister by a first amount; in response to the amount of fuel vapor purged from the fuel vapor canister below a first threshold, adjust the restriction valve to restrict flow restriction between the storage material in the fuel vapor canister by a second amount, where the second amount is greater than the first amount; in response to the amount of fuel vapor purged from the fuel vapor canister below a second threshold, adjust the restriction valve to restrict flow restriction between the storage material in the fuel vapor canister by a third amount, where the third amount is less than the second amount; and throughout a duration of the fuel vapor purging event, adjust a purge valve in the purge conduit to adjust an amount of vacuum provided to the fuel vapor canister in response to the amount of fuel vapor purged from the fuel vapor canister. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification