Patent ID: 7213450

Claim:
An evaporated fuel treatment device of an internal combustion engine having a canister that adsorbs evaporated fuel generated in a fuel tank for treatment, comprising: a sealing valve that is disposed between said fuel tank and said canister and controls a communication state between said fuel tank and said canister; stopping time control means that generally closes said sealing valve, and opens said canister to the atmosphere during stop of the internal combustion engine; stopping time sealing valve opening means that issues a valve opening instruction to said sealing valve when the internal combustion engine is stopped and differential pressure exceeding a valve opening determination value is generated between tank internal pressure and atmospheric pressure; tank internal pressure change detection means that detects a change in the tank internal pressure occurring between before and after said sealing valve opens; and closing failure determination means that determines closing failure of said sealing valve, when the change in said tank internal pressure is below a predetermined determination value.