SYSTEMS AND METHODS FOR VEHICLE EVAPORATIVE EMISSIONS SYSTEM DIAGNOSTICS
First Claim
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1. A method comprising:
- adjusting pressure in a vehicle evaporative emissions system by raising or lowering a vehicle body element; and
conducting a test in the evaporative emissions control system for detection of evaporative emissions based on the adjusted pressure.
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Abstract
Methods and systems are provided for conducting a diagnostic routine of the fuel vapor system using pressure generated by raising or lowering a vehicle body element such as a hood or a trunk. In one example, by utilizing lift gate cylinders coupled to the hood or trunk, during raising a hood or trunk, the fuel vapor system may be evacuated and during lowering the hood or trunk, the fuel vapor system may be pressurized. A change in vacuum or higher pressure in the fuel vapor system may be monitored over a time period to detect any undesirable evaporative emissions from the fuel vapor system.
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Citations
20 Claims
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1. A method comprising:
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adjusting pressure in a vehicle evaporative emissions system by raising or lowering a vehicle body element; and conducting a test in the evaporative emissions control system for detection of evaporative emissions based on the adjusted pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for a fuel vapor system of a vehicle, comprising:
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during a first condition, applying negative pressure on the fuel vapor system via the raising of a trunk or a hood of the vehicle; during a second condition, applying positive pressure on the fuel vapor system via the lowering of the trunk or hood of the vehicle; and during both the first and the second condition, conducting a test including indicating presence of evaporative emissions responsive to a change in fuel vapor system pressure following the applying of positive or negative pressure. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A fuel system for a vehicle engine, comprising:
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a fuel tank; a fuel vapor canister coupled to the fuel tank via an isolation valve; a canister purge valve positioned in a purge line between the fuel vapor canister and an engine intake manifold; a canister vent valve positioned in a vent line between the fuel vapor canister and atmosphere; one or more lift gate cylinders connecting each of a hood and a trunk of the vehicle to a body of the vehicle; a sensor for receiving operator input regarding a target position of the hood and/or trunk of the vehicle; a conduit coupling the lift gate cylinder to the vent line between the fuel vapor canister and the canister vent valve, the conduit including a lift gate valve; and a controller storing instructions in non-transitory memory, that when executed, cause the controller to; in response to operator input requesting vehicle hood and/or trunk opening, actuating the lift gate cylinder to open the hood or trunk; closing each of the vent valve and the purge valve; opening the lift gate valve to draw air out of the vent line until a fuel vapor system pressure is at a first pressure; and monitoring pressure bleed-up from the first pressure with the lift gate valve closed; and in response to operator input requesting vehicle hood and/or trunk closing, actuating the lift gate cylinder to close the hood or trunk; closing each of the vent valve and the purge valve; opening the lift gate valve to draw air out of the vent line until a fuel vapor system pressure is at a second pressure, higher than the first pressure; and monitoring pressure bleed-down from the second pressure with the lift gate valve closed. - View Dependent Claims (18, 19, 20)
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Specification