Patent ID: 7152587

Claim:
An evaporated fuel treatment device of an internal combustion engine comprising: an evaporated fuel introduction passage through which an evaporated fuel generated within a fuel tank is introduced into an intake system of the internal combustion engine; a relief valve that is opened when an internal pressure of the fuel tank becomes higher than an internal pressure of the evaporated fuel introduction passage by a predetermined value or greater so as to allow the evaporated fuel within the fuel tank to be introduced into the evaporated fuel introduction passage; a diagnosis module capable of switching between a communication state in which the evaporated fuel introduction passage is communicated with an atmosphere and a non-communication state in which the evaporated fuel introduction passage is not communicated with the atmosphere; a purge control valve that is opened so as to allow the evaporated fuel to be introduced into the intake system of the internal combustion engine; and a controller that opens the purge control valve when a predetermined purge condition is established during an operation of the internal combustion engine, wherein the controller prohibits the purge control valve from opening so as to be in a closed state when the diagnosis module is switched to be in the non-communication state in which the evaporated fuel introduction passage is not in communication with the atmosphere during the operation of the internal combustion engine.