Methods and systems for evaporative emissions control
First Claim
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1. A method, comprising:
- filling a fully air-filled fuel tank with fuel for a first time since vehicle assembly at a first station;
sealing the fuel tank;
monitoring fuel tank pressure prior to cranking an engine;
indicating degradation of a fuel system based on a change in the monitored fuel tank pressure; and
performing a first combustion event in the engine since the initial assembly of the vehicle at a second station.
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Abstract
Methods and systems are provided for reducing evaporative emissions from a vehicle by performing a fine leak test at a vehicle assembly plant. Fuel tank pressure generated after a green tank fueling event is monitored as the vehicle moves along an assembly line. A leak is determined based on a rate of pressure bleed-up over the duration, and accordingly the vehicle is directed to a repair station.
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Citations
20 Claims
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1. A method, comprising:
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filling a fully air-filled fuel tank with fuel for a first time since vehicle assembly at a first station; sealing the fuel tank; monitoring fuel tank pressure prior to cranking an engine; indicating degradation of a fuel system based on a change in the monitored fuel tank pressure; and performing a first combustion event in the engine since the initial assembly of the vehicle at a second station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for a fuel system of a vehicle, comprising:
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filling fuel for a first time in a green fuel tank following vehicle assembly at an assembly plant, with no prior fuel tank filling; sealing the fuel tank and monitoring a change in fuel tank pressure as the vehicle moves along stations at the assembly plant with the engine shutdown; and responsive to commanding of a first combustion event in the engine since the vehicle assembly, unsealing the fuel tank and indicating degradation of a fuel system based on the monitored change in fuel tank pressure being faster than a threshold rate. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A vehicle system, comprising:
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a vehicle including an engine; a fuel system including a fuel tank, a canister, a purge valve coupling the canister to the engine, and a vent valve coupling the canister to atmosphere; a pressure sensor coupled to the fuel tank; and a controller including computer readable instructions stored on non-transitory memory for performing a fuel system leak test on a vehicle as it moves between stations of an assembly plant and before a first combustion event in the engine, comprising; at a first station, filling the fuel tank to a threshold level on a first filling event in a fill history of the fuel tank; isolating the fuel tank from atmosphere by closing the vent valve; monitoring fuel tank pressure as the vehicle moves along a conveyor from the first station to a second station; indicating the presence of an orifice in the fuel system based on a rate of pressure bleed-down of the monitored fuel tank pressure; and performing the first combustion event in the engine since the assembly of the vehicle at the second station. - View Dependent Claims (19, 20)
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Specification