Toyota Jidosha Kabushiki Kaisha

Shota Kitano

Akihiro Katayama

Kazuyuki Noda

Masashi Hakariya

Yoshihisa Oda

Isao Nakajima

Yuichi Kohara

Kiyotaka Kushihama

Hitoshi Tanaka

Katsumi Adachi

An apparatus for detecting imbalance abnormality in an air-fuel ratio between cylinders in a multi-cylinder internal combustion engine according to the present invention increases a fuel injection quantity to a predetermined target cylinder to detect imbalance abnormality in an air-fuel ratio between cylinders at least based upon a rotation variation of the target cylinder after increasing the fuel injection quantity. The increase in the fuel injection quantity is carried out in the middle of performing the post-fuel-cut rich control. Since timing of the post-fuel cut rich control is used to increase the fuel injection quantity, the exhaust emission deterioration due to abnormality detection execution can be prevented as much as possible.

Apparatus for detecting imbalance abnormality in air-fuel ratio between cylinders in multi-cylinder internal combustion engine

An abnormality detection apparatus for a multi-cylinder internal combustion engine changes a fuel injection quantity of a predetermined target cylinder to detect an abnormality of an internal combustion engine based on values of rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity. The abnormality detection apparatus corrects the values of the rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity based on at least one of the number of revolutions of the engine and an engine load at a corresponding detection time.

Abnormality detection apparatus and abnormality detection method for multi-cylinder internal combustion engine

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Toyota, Japan

Shota Kitano