Knocking detection method for internal combustion engines and ignition timing control method therefor

摘要

An engine knocking detection method for detecting a knocking from a plurality of characteristic frequency components indicative of a knocking condition is provided. False information indicating a false knock occurrence due to an abnormal drop of the background level to be compared with the characteristic components is eliminated. Information indicating an occurrence of a knocking is extracted through comparison of the characteristic components and corresponding background levels. The background levels are compared with corresponding lower limiters when no knocking is taking place. When any one of the background levels is smaller than a lower limiter corresponding thereto, the lower limiter is adopted and set as a new background levels drops abnormally, a corresponding lower limiter thereof is effected to replace the faulty background level, thereby false information indicating the occurrence of a false knocking is prevented from being generated.