Methods and systems are provided for detecting leaks in an engine fuel system coupled in a vehicle including a first fuel tank and a second fuel tank, and a canister coupled together via a three-way valve. A leak test may be initially performed on the first fuel tank by supplying vacuum to the first
Methods and systems are provided for detecting leaks in an engine fuel system coupled in a vehicle including a first fuel tank and a second fuel tank, and a canister coupled together via a three-way valve. A leak test may be initially performed on the first fuel tank by supplying vacuum to the first fuel tank. The second fuel tank may be tested for leaks immediately following the leak test on the first fuel tank by recycling vacuum from the first fuel tank.
대표청구항▼
1. A method for performing leak testing in a fuel system of a vehicle engine, comprising: applying vacuum to a first fuel tank having a lower fuel fill level than a second fuel tank, including: applying vacuum to the first fuel tank via a vacuum pump, then ceasing the application of vacuum, monitori
1. A method for performing leak testing in a fuel system of a vehicle engine, comprising: applying vacuum to a first fuel tank having a lower fuel fill level than a second fuel tank, including: applying vacuum to the first fuel tank via a vacuum pump, then ceasing the application of vacuum, monitoring pressure changes in the fuel system based on output from a pressure sensor arranged in the fuel system, and determining whether there is a leak in the first fuel tank based on the monitored pressure changes; and thentransferring the vacuum from the first fuel tank to the second fuel tank, then ceasing the transfer of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the second fuel tank based on the monitored pressure changes. 2. The method of claim 1, further comprising measuring and comparing fuel fill levels of the first and second fuel tanks. 3. The method of claim 2, further comprising, when the fuel fill level of the second fuel tank is lower than the fuel fill level of the first fuel tank: applying the vacuum at first to the second fuel tank via the vacuum pump, then ceasing the application of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the second fuel tank based on the monitored pressure changes; and thentransferring the vacuum from the second fuel tank to the first fuel tank, then ceasing the transfer of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the first fuel tank based on the monitored pressure changes. 4. The method of claim 3, further comprising, when the first fuel tank and the second fuel tank have substantially equal fuel fill levels: estimating fuel temperature and a level of fuel slosh in each of the first and second fuel tanks;selecting one of the first fuel tank and the second fuel tank based on one or more of the estimated fuel temperatures and levels of fuel slosh, applying vacuum at first to the one selected fuel tank via the vacuum pump, then ceasing the application of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the one selected fuel tank based on the monitored pressure changes; and thentransferring the vacuum from the one selected fuel tank to a remaining fuel tank, then ceasing the transfer of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the remaining fuel tank based on the monitored pressure changes. 5. The method of claim 1, further comprising identifying leaks in a fuel system canister prior to applying the vacuum to the first fuel tank, and wherein each of the first fuel tank and the second fuel tank is isolated from the fuel system canister while identifying leaks in the fuel system canister by adjusting a valve to a first position, the valve coupled to each of the fuel system canister, the first fuel tank, and the second fuel tank. 6. The method of claim 5, wherein the applying of vacuum to the first fuel tank includes adjusting the valve to a second position in which the first fuel tank and the fuel system canister are in fluidic communication. 7. The method of claim 6, wherein transferring vacuum from the first fuel tank to the second fuel tank includes adjusting the valve to a third position in which the first fuel tank, the second fuel tank, and the fuel system canister are in fluidic communication. 8. The method of claim 5, wherein the pressure sensor is used to identify leaks in the fuel system canister, leaks in the first fuel tank, and leaks in the second fuel tank. 9. The method of claim 8, further comprising indicating a leak in the first fuel tank in response to a pressure in the first fuel tank being higher than a first threshold pressure. 10. The method of claim 9, further comprising indicating a leak in the second fuel tank in response to a pressure in the second fuel tank being higher than a second threshold pressure, the second threshold pressure being different from the first threshold pressure. 11. The method of claim 10, wherein the second threshold pressure is based on the vacuum transferred from the first fuel tank to the second fuel tank. 12. The method of claim 1, further comprising: when the vehicle engine is on, applying vacuum to the first fuel tank via one of intake manifold vacuum and the vacuum pump, then ceasing the application of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the first fuel tank based on the monitored pressure changes; and thentransferring the vacuum from the first fuel tank to the second fuel tank, then ceasing the transfer of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the second fuel tank based on the monitored pressure changes. 13. The method of claim 1, wherein the vehicle engine is fueled via the second fuel tank while identifying leaks in the first fuel tank, and wherein the vehicle engine is fueled via the first fuel tank while identifying leaks in the second fuel tank. 14. A method for a fuel system in an engine, comprising: adjusting a three-way valve to fluidically couple a first fuel tank to a vacuum source via a fuel system canister, then applying vacuum from the vacuum source to the first fuel tank, then ceasing the application of vacuum, monitoring pressure changes in the fuel system based on output from a pressure sensor arranged in the fuel system, and determining whether there is a leak in the first fuel tank based on the monitored pressure changes; and thenmodifying the three-way valve to fluidically couple the first fuel tank to a second fuel tank, then transferring the vacuum from the first fuel tank to the second fuel tank, then ceasing the transfer of vacuum, monitoring pressure changes in the fuel system based on output from the pressure sensor, and determining whether there is a leak in the second fuel tank based on the monitored pressure changes. 15. The method of claim 14, wherein the three-way valve blocks fluidic communication between the first fuel tank and the second fuel tank while diagnosing the first fuel tank for leaks, and wherein diagnosing the second fuel tank for leaks is performed sequentially after diagnosing the first fuel tank for leaks to distinguish degradation between the first fuel tank and the second fuel tank. 16. The method of claim 14, further comprising diagnosing the fuel system canister for leaks prior to diagnosing the first fuel tank for leaks, and wherein diagnosing the fuel system canister for leaks includes adjusting the three-way valve to decouple the fuel system canister from each of the first fuel tank and the second fuel tank. 17. A method for diagnosing leaks in a fuel system of an engine, comprising: estimating fuel fill levels in at least two fuel tanks; andsequentially performing leak tests for two or more of the at least two fuel tanks in order of their fuel fill levels, from lowest to highest. 18. The method of claim 17, wherein the fuel fill levels are estimated using fuel level sensors positioned in each of the at least two fuel tanks. 19. The method of claim 17, wherein performing a leak test for a fuel tank of the at least two fuel tanks comprises: applying vacuum to the fuel tank undergoing the leak test; and thenceasing application of the vacuum, monitoring changes in pressure in the fuel system with a pressure sensor arranged in the fuel system, and determining whether there is a leak in the fuel tank based on the monitored pressure changes.
연구과제 타임라인
LOADING...
LOADING...
LOADING...
LOADING...
LOADING...
이 특허에 인용된 특허 (1)
DeBastos, Timothy; Kacewicz, John Michael; Bohr, Scott; Pearce, Russell Randall; Kragh, Christopher; Sullivan, Patrick; Euliss, William; Kluzner, Michael Igor, Method and system for fuel vapor control.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.