| 摘要 |
PURPOSE:To enable a normal knock detection to be carried out outside a fail judgement range by installing a reset means for resetting a fail judgement signal in the rising phase of a knock judgement signal. CONSTITUTION:A knock sensor 1 detects the oscillation of an engine Eg and outputs signals to a knock judgement processing circuit 4 and a fail judgement processing circuit 5. And a knock judgement signal from the knock judgement processing circuit 4 and a fail judgement signal from the fail fudgmenet processing circuit 5 are synthesized together in an OR circuit 7 and outputted to a microcomputer 3 via a signal line 8. In this case, if an engine speed is low and the signal output of the knock sensor 1 gets out of a fail judgement range, a fail judgement signal of a high level outputted from the fail judgement processing circuit 5 is reset by a fail judgement reset circuit 6 which detects the rise of a knock judgement signal caused by knock generation. Thus, normal knock detection is made possible even outside a fail judgement range. |
