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WIND SPEED INFERENCE DURING VEHICLE KEY OFF CONDITION FOR EONV COMPENSATION

IP.com Disclosure Number: IPCOM000238399D
Publication Date: 2014-Aug-22
Document File: 1 page(s) / 193K

Publishing Venue

The IP.com Prior Art Database

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WIND SPEED INFERENCE DURING VEHICLE KEY OFF CONDITION FOR EONV COMPENSATION

Vehicles sold in North America are required to perform Evap leak detection as part of OBDII requirements. Green states are required to monitor for 0.02" leaks as part of the Clean Air Act Section 177. (CAA) IN MY2017, all states have to perform 0.02" leak tests. For regular gasoline engines, a technique called Engine Off Natural Vacuum (EONV) is used to perform leak detection. EONV is dependent on human factors and the environment. EONV relies on heat rejection from the hot engine to reach the tank and warm the bulk fuel during driving. EONV can either pass on a pressure build or on a vacuum build. A typical EONV hot weather run results in a robust pressure build. It typically takes a few minutes to pass EONV in the summer months. Heat radiation from hot road surface and sun loading supplements the heat rejection from the engine and underbody. A typical EONV cold weather run results in a vacuum build as cold air cools the bulk fuel temperature. A major noise factor that affects EONV beta error (false pass) is wind. Wind can dramatically cool the fuel and mask a 0.02" leak in the system. Currently, there is no method of inferring or compensating for wind speed when the vehicle is parked and running EONV.

Method

The method infers wind speed in the stationary vehicle using the existing radio antenna. The advantage of using the antenna is that it deflects when the wind blows. Also, the anten...