Method controlling air-fuel ratio

Claim 1

In a method of controlling fuel injection in an internal combustion engine wherein the fuel injection timing for operation of a fuel injector is based at least on a basic fuel injection time and a compensation factor which is determined in a learning process during engine operation for each of a plurality of operating regions formed by a range of values of at least two predetermined engine conditions, a method of determining the values of said compensation factor for said plurality of operating regions, comprising the steps of: (a) calculating said compensation factor at predetermined intervals during the operation of said engine; (b) storing a calculated compensation factor in a first memory at a storage location therein which represents an operating region defined by the values of said predetermined engine conditions existing at the time the compensation factor is calculated; (c) reproducing the contents of said first memory in a second memory when a compensation factor has been stored in a predetermined number of the storage locations of said first memory; (d) estimating and storing compensation factors in storage locations of said first memory other than said predetermined number of storage locations on the basis of the compensation facotrs previously stored so that all storage locations hold a compensation factor; (e) transferring the contents of said first memory to a third memory after a compensation factor has been stored in all storage locations of said first memory; (f) reproducing the contents of said second memory in said first memory and continuing the storing of calculated compensation factors in said first memory; and (g) determining the ignition fuel timing for said engine on the basis of said basic fuel injection time and the compensation factors stored in said third memory.