Patent ID: 6021767
Filing Date: 2000-02-08
Classification: F02D,G05B

Abstract:
In an air-fuel ratio control system for a multi-cylinder engine having a plurality of cylinders and an exhaust system connected to said cylinders, including air-fuel ratio-detecting means arranged in said exhaust system for detecting an air-fuel ratio of a mixture supplied to said engine and for generating an output indicative of said air-fuel ratio of said mixture, an adaptive controller for determining an amount of fuel to be supplied to said engine with a first predetermined repetition period in a manner such that said output from said air-fuel ratio-detecting means becomes equal to a desired value, and adaptive parameter-adjusting means for adjusting adaptive parameters used by said adaptive controller,the improvement wherein:said adaptive parameter-adjusting means comprises:adaptive parameter-calculating means for calculating said adaptive parameters with a second predetermined repetition period longer than said first predetermined repetition period and for generating output data indicative of results of said calculation; andsmoothing means for smoothing said output data from said adaptive parameter-calculating means and for generating output data indicative of the smoothed data with a repetition period at least equal to said first predetermined repetition period;wherein said adaptive controller uses the smoothed data generated from said smoothing means as values of said adaptive parameters.