Patent ID: 6223732
Filing Date: 2001-05-01
Classification: F02M

Abstract:
An evaporated fuel treatment apparatus for an internal combustion engine having a fuel tank, a canister having an opening to the atmosphere, a passage allowing the fuel tank to communicate with the canister, a purging passage allowing the canister to communicate with the intake manifold of the engine, the intake manifold having a reduced pressure as the engine intakes air, and a pressure sensor for detecting the internal pressure of the fuel tank, said apparatus comprising:a controller coupled to the pressure sensor and configured to control opening of the fuel tank alternately to the atmosphere and to a negative pressure, said controller detecting the presence or absence of leakage on the basis of the change in negative pressure that occurs after the fuel tank has been placed under a negative pressure, wherein said controller prohibits the detection of the presence or absence of the leakage in response to a change in the internal pressure of the fuel tank in the direction of negative pressure when the fuel tank is not opened to the atmosphere.