US 6,631,635 B2Granted

Fault diagnostic apparatus of evaporation purge system

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsRyoichi Hanazaki, Masaki Nakamichi

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Abstract

To obtain a fault diagnostic apparatus of an evaporation purge system by which a fault detection of a purge vent valve can accurately be performed with no wrong judgment. There are included: a tank internal pressure detecting means for detecting an internal pressure of a fuel tank; a valve control means for controlling closing and opening of a purge control valve and the purge vent valve; a purge control valve fault detecting means for detecting a fault of the purge control valve on the basis of a detected output of the tank internal pressure detecting means when the purge control valve and the purge vent valve are closed; and a purge vent valve fault detecting means for detecting a fault of the purge vent valve on the basis of the detected output of the tank internal pressure detecting means when the purge control valve and the purge vent valve are open, and the purge vent valve fault detecting means performs the fault detection of the purge vent valve only when the purge control valve fault detecting means judges that the purge control valve is normal.

Claims6

Dependent claims

In an evaporation purge system including:

a fuel tank;
a canister having an intake hole;
a purge control valve provided in a purge passage connecting said canister and an intake system of an internal combustion engine;
and
a purge vent valve for opening and closing the intake hole of said canister,
a fault diagnostic apparatus of an evaporation purge system, comprising:
tank internal pressure detecting means for detecting internal pressure of said fuel tank;
valve control means for controlling closing and opening of said purge control valve and said purge vent valve;
purge control valve fault detecting means for detecting a fault of said purge control valve on the basis of detected output of said tank internal pressure detecting means, at the time of the closed state of said purge control valve and said purge vent valve;
and
purge vent valve fault detecting means for detecting a fault of said purge vent valve on the basis of detected output of said tank internal pressure detecting means, at the time of the opening state of said purge control valve and said purge vent valve,
wherein said purge vent valve fault detecting means performs fault detection of said purge vent valve, only when said purge control valve fault detecting means judges that said purge control valve is normal.

9 more elements

Dependencies are inferred from the claim text.