Patent ID: 6698280
Filing Date: 2004-03-02
Classification: F02M

Abstract:
A failure test apparatus for a fuel-vapor purging system for adsorbing fuel vapor in a fuel tank into a canister and purging fuel in the canister to an intake system of an internal combustion engine as needed, the system having at least one valve, the apparatus comprising:first test means for providing a differential pressure between the inside and the outside of the fuel-vapor purging system, measuring the internal pressure with the fuel-vapor purging system when in an airtight condition and determining whether a leak exists in the fuel-vapor purging system from the behavior of the internal pressure, the determination by the first test means including a differential-pressure forming process of creating a differential pressure between the inside and the outside of the fuel-vapor purging system, a sealing process for making the fuel-vapor purging system airtight when the differential pressure exists, and a differential-pressure releasing process for releasing the differential pressure; and second test means for measuring the internal pressure of the fuel-vapor purging system in association with one or more of the processes to thereby detect a failure in the valve based on the behavior of the internal pressure.