Patent ID: 6363919
Filing Date: 2002-04-02
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, the opening being opened or closed by a vent shut valve, 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:correction detecting means for detecting the rate of change in the internal pressure of the fuel tank when the fuel tank is closed after being placed in the atmospheric pressure; leakage detecting means for detecting the rate of change in the internal pressure of the fuel tank when the fuel tank is closed after being placed in a negative pressure; judgement means for judging the presence or absence of leakage in the fuel tank on the basis of the detection results by the leakage checking means and the correction checking means; calculating means for calculating the amount of fuel consumption at the time of detection by the correction checking means and the amount of fuel consumption at the time of detection by the leakage checking means; and judgement prohibiting means for prohibiting a judgement of presence or absence of leakage from being made by the judgement means in cases where the amounts of fuel consumption calculated at the time of correction checking and at the time of leakage checking are substantially different from each other.