Determination of Weak Knock Characteristics for Two-Stroke Spark Ignition UAV Engines Based on Mallat Decomposition Algorithm

Figure 18

Eight signal components are obtained by using the wavelet packet energy method. (a) Eight signal components are decomposed from the engine vibration signal at 5000 rpm with an ignition advance angle of 25°CA. (b) Eight signal components are decomposed from the engine vibration signal at 5000 rpm with an ignition advance angle of 27°CA.

(a)

(b)