Patent ID: 9043121
Filing Date: 2015-05-26
Classification: F02D

Abstract:
1. An air-fuel ratio variation abnormality detecting device for an internal combustion engine that is equipped with a plurality of cylinders and a plurality of fuel injection valves that are provided for the plurality of the cylinders respectively, comprising: a controller; the controller being configured to calculate a required fuel injection amount that fulfills an operation condition of the internal combustion engine, the controller being configured to calculate fuel injection amounts that are amounts of fuel injected from the plurality of the fuel injection valves respectively based on the required fuel injection amount, the controller being configured to incrementally correct at least one of the fuel injection amounts such that the fuel injection amount becomes equal to or larger than a predetermined reference value, if the fuel injection amount is smaller than the reference value, the controller being configured to set a first injection ratio and a second injection ratio based on the incrementally corrected fuel injection amount, the first injection ratio and the second injection ratio being ratios between an amount of fuel injection from at least one first fuel injection valve and an amount of fuel injection from remaining second fuel injection valve in one cylinder respectively, and the first injection ratio and the second injection ratio having different value respectively, and the controller being configured to detect an abnormality of air-fuel ratio variation based on fluctuations in a predetermined output of the internal combustion engine at a time when fuel is injected at the first injection ratio and at a time when fuel is injected at the second injection ratio.