Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Susumu Saito

Toru Hashimoto

Hiroshi Tanaka

Akira Takahashi

Takeshi Jimbo

Takeshi Imaizumi

A method of detecting a fault of an exhaust gas recirculation system of an internal combustion engine, comprising detecting a temperature relating to a temperature of a gas recirculating through the exhaust gas recirculation system when the system is in a condition in which the system should be operated to return part of an exhaust gas of the engine to an intake passage, and detecting that the exhaust gas recirculation system is defective when the detected temperature is lower than a fault discriminating value. A condition of air to be sucked into the engine, such as intake air temperature and atmospheric pressure, is detected, and the fault discriminating value is set in accordance with the detected air condition, whereby abnormality or fault of the exhaust gas recirculation system can be detected accurately and reliably. Preferably, the fault detection is inhibited until the engine temperature reaches a predetermined value and/or a predetermined time period elapses after the start-up of the engine, whereby erroneous fault detection can be prevented.

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Toyota, Japan

Susumu Saito