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AN EONV HEAT REJECTION ENERGY AGGRESSIVENESS INDEX

IP.com Disclosure Number: IPCOM000238410D
Publication Date: 2014-Aug-25
Document File: 1 page(s) / 224K

Publishing Venue

The IP.com Prior Art Database

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AN EONV HEAT REJECTION ENERGY AGGRESSIVENESS INDEX

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 EONV is used to perform leak detection. Engine Off Natural Vacuum relies on heat rejection from the hot engine to reach the tank and warm the bulk fuel during driving.At key off, if sufficient heat rejection was generated during the drive cycle, the PCM stays alive and executes an Evap leak detection test. The timing of the heating energy rejection into the fuel tank can affect EONV results significantly. High speed driving is a good source of the heat energy to the fuel tank. But, a high speed drive followed by a long idle reduces the effect of the previous high speed driving. The bulk fuel temperature drops significantly with a long idle. Hence, a method is needed to infer when and how long the aggressiveness in the drive cycle occurred. EONV results would be compensated accordingly.

Method

The invention aims to create a finite element of the heating energy and the aging effect of the total energy that goes to the fuel tank. Current methods only count the total energy during the entire driving cycle regardless when the energy was generated. The methods do not consider when the maximum energy was rejecte...