Evaporated fuel treatment apparatus for internal combustion engine

摘要

An evaporated fuel treatment apparatus having a correction checking means for detecting the state of change in the internal pressure of the fuel tank when the fuel tank is closed after being placed under atmospheric pressure, a leakage checking means for detecting the state of change in the internal pressure of the fuel tank when the fuel tank is closed after being placed under a negative pressure, and a judgement means for judging the presence or absence of leakage in the fuel tank on the basis of the detection results obtained by the leakage checking means and the correction checking means. The apparatus includes calculating means for calculating the amount of fuel consumption at the time of correction checking and the amount of fuel consumption at the time of leakage checking, and judgement prohibiting means for prohibiting a judgement of the 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. As a result, a judgement of the presence or absence of leakage in the tank system is prevented from being performed in cases where such a judgement might be inaccurate.