To maximally prevent deterioration in exhaust emission caused by the execution of abnormality detection.
An apparatus for detecting an abnormality of an inter-cylinder air-fuel ratio variation of a multi-cylinder internal combustion engine increases the fuel injection quantity of a prescribed target cylinder and detects an abnormality of an inter-cylinder air-fuel ratio variation on the basis of at least a change in the rotation of the target cylinder after an increase in fuel injection quantity. The increase in the fuel injection quantity is executed during the execution of prescribed rich control. The increase in the fuel injection quantity is executed by utilizing the timing of the rich control. Therefore, it is possible to maximally prevent the deterioration in exhaust emission caused by the execution of abnormality detection.
TANAKA HITOSHI
NAKAJIMA ISAO
ODA SUMIHISA
HAKARIYA MASAFUMI
KUSHIHAMA KIYOTAKA
NODA KAZUYUKI
KATAYAMA AKIHIRO
OBARA YUICHI
ADACHI KATSUMI
KATO JUICHI
OGAWA YOHEI
