Failure diagnosis device of fuel evaporation preventive apparatus

摘要

A failure diagnosis device of a fuel evaporation preventive apparatus including: a fuel evaporation preventive apparatus having a canister having an atmospheric hole communicating with outside air and installed in the middle of a purge passage communicating a fuel tank with an intake pipe, for preventing evaporation of fuel by adsorbing at any time fuel gas generated in the fuel tank by an adsorber incorporated in the canister and pertinently introducing the adsorbed fuel gas into the intake pipe by controlling a purge control valve in accordance with a running state of an internal combustion engine; an initializing apparatus for controlling an inner pressure of the fuel tank to a predetermined initial pressure; a pressure controlling apparatus for changing the initial pressure to a predetermined target pressure and controlling a purge amount at that time to a constant flow rate by closing the atmospheric hole and driving the purge control valve; a hermetically enclosing apparatus for constituting a hermetically enclosed section in the fuel evaporation preventive apparatus by closing both the purge control valve and the atmospheric hole when the inner pressure of the fuel tank reaches the target pressure; a pressure detecting apparatus installed in the hermetically enclosed section; and a failure diagnosing apparatus for diagnosing failure of the fuel evaporation preventive apparatus based on a change of an inner pressure of the hermetically enclosed section.