Abstract
Knock control has been spread through spark-ignition engines, in order to keep ignition timing the optimal for fuel economy. However, there is a problem that performances will fall at the time of acceleration and air-fuel ratio changing. The reason is in the delay of knock detection. In a lean-burn engine, the influence is large. In this paper, wavelet transform was applied to processing knock signals. Moreover, a new method was proposed and the scale-power spectrum was compared in plural resonant-vibration modes at the same crank angle. The pressure signal was measured with a 4-cycle engine and it was sampled at high speed and taken in by PC. As results of carrying out off-line analysis, the prospect which knock can be detected knock in one- combustion cycle was acquired.
