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ROAD GRADE INFERENCE METHOD FOR FUEL LEVEL INDICATION ROBUSTNESS

IP.com Disclosure Number: IPCOM000240454D
Publication Date: 2015-Jan-30
Document File: 1 page(s) / 331K

Publishing Venue

The IP.com Prior Art Database

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ROAD GRADE INFERENCE METHOD FOR FUEL LEVEL INDICATION ROBUSTNESS

A conventional automotive float arm fuel level sender system has a difficult time measuring fuel level when the vehicle is parked on an incline, and may either over-estimate or under-estimate the actual fuel level. During operation of the vehicle, fuel level is heavily filtered in order to correct errors from fuel level fluctuations during operation. After parking on a hill, the vehicle will store the filtered fuel level when the vehicle is shut off. On the subsequent key-on, the fuel level inference calculation is seeded with the measured fuel level. Because the vehicle is parked on a hill, the measured fuel level may be much 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 can cause 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.Furthermore, Evap leak monitor thresholds (EONV) are typically a function of fuel level. Parking on grades yields the wrong thresholds, resulting in monitor capability issues.False refuel detection can also confuse other vehicle features such as the Miles-To-Empty calculation as well as stuck Fuel Level Indicator FLI diagnostics.

Method

This method utilizes ultrasonic sensors to detect parking on grades. Ultrasonic sensors are non- con...