| 摘要 |
PURPOSE: An opening adherence diagnosis method for a pressure switch inside a fuel leak diagnostic system is provided to diagnose accurately whether fuel actually leaks from a fuel tank or not, thereby providing a driver with a guidance by the exact diagnosis of the cause of the leak of a fuel tank. CONSTITUTION: An opening adherence diagnosis method for a pressure switch inside a fuel leak diagnostic system comprises the following steps. The engine control unit(200) receives an output signal from a pressure switch sensor(100) in the fuel leak diagnostic system when an engine starts. The pressure switch state about the fuel tank is adjudged by using the output signal. The fuel leak diagnosis is performed when the pressure switch state is in the open state. Determination is performed on whether the pressure switch state is changed or not during the performing process of a fuel leak diagnosis. The diagnosis result is output after a final diagnosis, wherein the cause of an error is determined as a fuel leak of a fuel tank. The diagnosis result is output after the final diagnosis, wherein the cause of an error is determined as the opening adherence of the pressure switch. [Reference numerals] (100) Pressure switch sensor; (200) Engine control unit; (AA) Fuel distributor; (BB) Internal combustion engine; (CC) Fuel pressure regulator; (DD) Fuel cut-off valve; (EE) Fuel tank |
