Fault condition detecting method for motor vehicle fuel tank or fuel vapor cleaning apparatus in which expected and measured rate of pressure change in the fuel tank are compared to ensure early fault detection

摘要

The fuel tank is shut off or isolated from an activated carbon container for storing fuel vapor and the engine. The rate of change of pressure in the fuel tank is estimated according to engine conditions, i.e. expected fuel consumption, and measurement of the actual rate of pressure change. The two values are compared and if the difference exceeds a threshold value a fault condition is indicated. An Independent claim is made for a device for detecting faults in a fuel tank and or a fuel tank vapor cleaning apparatus for use with a motor vehicle combustion engine.