AIR-FUEL RATIO CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To easily improve air-fuel detection accuracy without any special processing such as the change of a sampling frequency depending on a speed of an internal combustion engine. SOLUTION: An air-fuel ratio control device for an internal combustion engine comprises: a pulse signal generator disposed to a crankshaft of a cylinder of the internal combustion engine; an oxygen concentration sensor disposed to an exhaust system of the internal combustion engine to generate outputs in proportion to an oxygen concentration in exhaust; a means for reading the output of the oxygen concentration sensor in a predetermined period in synchronization with the rotation of the crankshaft and shorter than the period of the top dead center of the internal combustion engine; a means for calculating an integrated value of top dead center periods of read oxygen concentration sensor outputs to acquire an air-fuel ratio of the exhaust of the internal combustion engine based on the integrated value; and a control means controlling the air-fuel ratio of air-fuel mixture supplied to the internal combustion engine based on the air-fuel ratio. COPYRIGHT: (C)2005,JPO&NCIPI