초록 ▼

An on-board evaporative emission leak detection system and method that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. A test includes an initialization, or stabilization, phase during which a differential between pressure in the evaporative emission spa

An on-board evaporative emission leak detection system and method that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. A test includes an initialization, or stabilization, phase during which a differential between pressure in the evaporative emission space and atmospheric pressure is created, and then varied, over time, within a range of differential pressures suitable for performing a leak detection test. This varying of pressure differential alternately increases the created pressure differential above a nominal pressure differential and decreases the created pressure differential below the nominal pressure differential. The leak detection test is then performed.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of initializing an evaporative emission space of a fuel storage system of an automotive vehicle preparatory to performing a leak detection test on the evaporative emission space, the vehicle being powered by a fuel-consuming engine and including an evaporative

[ What is claimed is:] [1.]1. A method of initializing an evaporative emission space of a fuel storage system of an automotive vehicle preparatory to performing a leak detection test on the evaporative emission space, the vehicle being powered by a fuel-consuming engine and including an evaporative emission control system for purging fuel vapor from the evaporative emission space to the engine for combustion therein during conditions conducive to purging, the method comprising:creating a differential between pressure in the evaporative emission space and, atmospheric pressure sufficient to perform a leak detection test;alternately increasing the created pressure differential above a nominal pressure differential and decreasing the created pressure differential below the nominal pressure differential, a plurality of cycles over time, within a range of differential pressures sufficient to perform a leak detection test; and thenisolating the evaporative emission space from communication with both the engine and atmosphere, and performing a leak detection test.