Preignition detecting system and method

摘要

A preignition detecting system capable of detecting a preigniting condition (PI) at an early time. It is detected that in an abnormal vibration determining step the occurrence of vibration larger than a predetermined threshold level after the passage of a first predetermined period of time from the ignition has been detected and that said abnormal vibration determining step has determined the occurrence of vibration larger than a predetermined threshold level after the passage of a second predetermined period of time longer than said first predetermined period of time from the ignition. In a preignition determining step it is than determinined that preignition is occurring when it is determined at said abnormal vibration detecting step that abnormal vibration is occurring.