Method and apparatus for air fuel ratio adjustment

Abstract

The air fuel ratio of an engine adapted to run on a mixture of alcohol and gasoline can be adapted according to the invention, by a method, wherein said air fuel ratio is controlled by means of an ethanol adaptation value, comprising the following steps: reducing the enrichment factor from an initial value until a lean switch from rich conditions to lean conditions is detected, determining a first enrichment factor value at which the lean switch occurs, Increasing the enrichment factor until a rich switch from lean conditions to rich conditions is detected, determining a second enrichment factor value at which the rich switch occurs, calculating the average value between the first enrichment factor value and the second enrichment factor value, adjusting the air fuel ratio by means of said average value.

Dependencies are inferred from the claim text.