| 摘要 |
PURPOSE:To prevent a knock judging level from becoming too large by preparing the knock judging level on the basis of a value of a cumulative percentage point of the maximum value distribution in the combustion block of knock sensor signal. CONSTITUTION:In an ignition timing control circuit 8 at the time of an engine being started and ignition timing computation being interrupted, the basic ignition timing is computed from information on engine speed, load, and the like, as well as the maximum value in the specified block of the output signal of a knock sensor 6 is read for each cylinder on the basis of the output signal of a peak-hold circuit 7. The value of a cumulative percentage point of this maximum value V distribution is also computed. Whether or not the engine is in the knock control state is then judged from load and the like, and in case of being judged affirmative, a per-cylinder knock judging level Vref is obtained on the basis of the value of the cumulative percentage point of distribution. At the time of V>Vref, the generation of knocking is judged, and the ignition timing is retard-controlled. |
