초록 ▼

A remotely actuatable diagnostic valve biased normally open is disposed in the air inlet of a vehicle fuel tank vapor storage canister and a thermistor disposed to sense vapor temperature above the liquid level in the fuel tank. Upon engine shutdown, the valve is remotely actuated to close. When the

A remotely actuatable diagnostic valve biased normally open is disposed in the air inlet of a vehicle fuel tank vapor storage canister and a thermistor disposed to sense vapor temperature above the liquid level in the fuel tank. Upon engine shutdown, the valve is remotely actuated to close. When the fuel vapor in the tank cools to form a vacuum in the tank, the vacuum overcomes the valve bias and holds the valve shut when the valve is remotely de-actuated. A valve position sensor provides confirmation that the valve has been held shut by the vapor vacuum when the valve is de-actuated. If a leak exists the vacuum will be insufficient to hold the valve closed after remote de-actuation; and, the valve is biased open, whereupon the valve position sensor provides a fault indication signal.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of detecting vapor leaks in a motor vehicle fuel tank vapor management system of the type having a vapor storage canister comprising:(a) disposing a valve in the air inlet of said canister and providing a fluid pressure responsive member in said valve and biasi

[ What is claimed is:] [1.]1. A method of detecting vapor leaks in a motor vehicle fuel tank vapor management system of the type having a vapor storage canister comprising:(a) disposing a valve in the air inlet of said canister and providing a fluid pressure responsive member in said valve and biasing said member to the open position with a predetermined force;(b) sensing fuel vapor temperature in said tank and remotely actuating said valve to the closed position when the tank temperature has decreased by a predetermined amount;(c) applying the tank pressure to said pressure responsive member and overcoming said predetermined force and holding said valve closed when said tank vapor pressure is below a certain sub-atmospheric vapor pressure and opening said valve with said predetermined force if said tank vapor pressure rises above said certain sub-atmospheric pressure.(d) detecting the position of said valve and thereby determining that said valve is open and leakage is present in said system; and,(e) providing a fault indication when said leakage is present.