Patent ID: 7043972

Claim:
An evaporated fuel treatment device for internal combustion engine that uses a canister to absorb evaporated fuel generated in a fuel tank for evaporated fuel treatment purposes, said device comprising: a sealing valve for controlling the continuity between said fuel tank and said canister; a differential pressure generation condition judgment means for judging whether a differential pressure generation condition is established, said condition being established when the sealing valve is expected to be closed and differential pressure is expected to be generated between both sides of the sealing valve; a differential pressure detection means for detecting the difference between a canister side pressure which exists in a canister side area of the sealing valve and a tank internal pressure when said differential pressure generation condition is established; and an open failure normality judgment means for judging that no open failure exists in said sealing valve when said differential pressure detection means detects a differential pressure higher than a judgment value.