PURPOSE: To prevent the angle of unnecessary lag, by bringing ignition timing to the angle of lag until the ignition timing of the limit that knocking is formed by discriminating knocking, and by restricting the quantity of the angle of lag within the limit field of the angle of lag decided in response to the conditions of an engine.
CONSTITUTION: The output of a knocking discriminating circuit 15 is signals showing as to whether or not knocking is generated, and the signals are applied to a set circuit 16 for the angle of lag. The set circuit 16 for the angle of lag continuously increases the quantity of the angle of lag every six degree and successively delays ignition timing if knocking is formed. The output is applied to a converting circuit 18 through a multiplying circuit 17. The converting circuit 18 limits the quantity of the angle of lag so that the angle of lag not become not more than angle of the maximum lag, the angle of the minimum lead, even if a vibration sensor 13, etc. are broken and the angle of ignition timing continuously lags.
FUJISAWA HIDEYA
KAWASHIMA YUTAKA
NINOMIYA MASAKAZU
KAWAI HISASHI
MATSUI TAKESHI
NIPPON SOKEN