DEVICE FOR DETECTING ABNORMAL AIR-FUEL RATIO VARIATION IN CYLINDER FOR MULTI-CYLINDER INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To properly detect abnormal air-fuel ratio variations in cylinders in a multi-cylinder internal combustion engine applied with stall avoidance control.;SOLUTION: The device for detecting abnormal air-fuel variations in the cylinders executes: control for detecting the abnormal air-fuel ratio variations to detect the air-fuel ratio variations in the cylinders based on output variations when a fuel injection amount is forcibly changed; and the stall avoidance control for executing torque increasing control for an engine not to be stalled based on a specific output of the engine. To detect the abnormal variations, when the fuel injection amount is changed (increased or decreased) (S801), torque increase control (S804) is suppressed from being executed (S805). Accordingly, improvement in rotation speed by torque increase processing is suppressed, so that the abnormal air-fuel variations can more properly be detected.;COPYRIGHT: (C)2013,JPO&INPIT