초록 ▼

A method is provided for detecting a very small leak in an evaporative emission control system of an automotive vehicle. The method includes sealing the evaporative emission control system at a key-off event and monitoring a vacuum switch coupled to the evaporative emission control system for a clos

A method is provided for detecting a very small leak in an evaporative emission control system of an automotive vehicle. The method includes sealing the evaporative emission control system at a key-off event and monitoring a vacuum switch coupled to the evaporative emission control system for a closing event due to a natural vacuum created in the evaporative emission control system as it cools. If the closing event is not detected, the method determines if a leak detection timer has exceeded a predetermined threshold value. If the timer has exceeded the predetermined threshold value, the method sets a fault code indicating that the very small leak has been detected. Preferably, the leak detection timer includes a first time value corresponding to an amount of time the automotive vehicle has been operating since a previous small leak detection test was conducted and a second time value corresponding to an amount of time the automotive vehicle has been inoperative since a previous small leak detection test was conducted. The first time value includes a series of individual trip times of the automotive vehicle while the second time value includes a series of individual inoperative session times of the automotive vehicle.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of detecting a very small leak in an evaporative emission control system of an automotive vehicle comprising:sealing said evaporative emission control system at a key-off event;monitoring a vacuum switch coupled to said evaporative emission control system for a

[ What is claimed is:] [1.]1. A method of detecting a very small leak in an evaporative emission control system of an automotive vehicle comprising:sealing said evaporative emission control system at a key-off event;monitoring a vacuum switch coupled to said evaporative emission control system for a closing event due to a vacuum created in said evaporative emission control system;determining if a leak detection timer has exceeded a predetermined threshold value if said closing event is not detected; andsetting a fault code indicating that said very small leak has been detected if said timer has exceeded said predetermined threshold value;wherein said leak detection timer further comprises a first time value corresponding to an amount of time said automotive vehicle has been operating since a previous small leak detection test was conducted.