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ELCM VALIDATION FOR FUEL LEVEL WHEN PARKING ON GRADE

IP.com Disclosure Number: IPCOM000237128D
Publication Date: 2014-Jun-04
Document File: 1 page(s) / 239K

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The IP.com Prior Art Database

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ELCM VALIDATION FOR FUEL LEVEL WHEN PARKING ON GRADE

Vehicles sold in North America are required to perform Evap leak detection. Green states require monitoring for 0.02" leaks.For HEVs, engine run time is limited, hence a vacuum pump is required for leak detection. One such vacuum pump is the ELCM made by Denso Corporation.ELCM test sequence begins by obtaining a "reference check" by turning on pump and evacuating small volume where internal 0.02" reference orifice is located. The reference vacuum value obtained becomes pass/fail threshold.Parking on an incline poses issues with the fuel level sender, which may either over-estimate or under-estimate the fuel level.When parked on an incline, the heavily filtered fuel level at time of key- off may not be representative of the true fuel level resulting from parking on incline. On the subsequent key-on, the fuel level is seeded with the actual fuel level which does represent parking on an incline and the new fuel level has been found to be substantially greater than the filtered fuel level at time of key- off resulting in false fuel refill event detection.This poses issues with false refuel detection which causes OBD monitors to abort. For instance, the Evap OBD monitor typically aborts if refuel is detected. This is due to refueling vapors being a noise factor during Evap leak detection.False refuel detection can also confuse other vehicle features such as the Miles-To-Empty calculation as well as stuck FLI...