Patent ID: 6760657
Filing Date: 2004-07-06
Classification: F02D,G05B

Abstract:
An air-fuel ratio control device for an engine with a combustion chamber for burning a mixture of air and fuel, comprising:a fuel injector which injects fuel in the engine to generate the mixture; a sensor which detects an air-fuel ratio of the mixture from a composition of exhaust gas of the engine; and a programmable controller programmed to: calculate a dead time which represents a lag between the variation of air-fuel ratio of the mixture in the combustion chamber and the variation of air-fuel ratio which is detected by the sensor; calculates an estimated state quantity by applying a dead time compensation according to Smith method and a disturbance compensation to the air-fuel ratio detected by the sensor; calculate an air-fuel ratio feedback correction amount based on the estimated state quantity and a predetermined target air-fuel ratio through a sliding mode control process; and control a fuel injection amount of the fuel injector based on the air-fuel ratio feedback correction amount.