Time-frequency characteristics research for pressure waves of fuel injection system of diesel engine

In research of pressure wave of fuel injection system of diesel engine, with Wigner-Ville distribution, the time-frequency characteristics of pressure wave in fuel injection system of a diesel engine under condition of liquid-gas tow-phase flow was analyzed. The comparison of its results with the results of wavelet function analysis was made. The results show that using Wigner-Ville distribution the energy density of pressure wave of fuel injection system in time and frequency field can be better described and the change of frequency of this unstable signal with time can be better reflect. When long living time cavitation existed in fuel injection system, the energy density of pressure wave, which included some high frequency energy besides low frequency energy in this energy, concentrates mostly on the first pressure wave and there is not any high frequency energy in the second pressure wave. When short living time cavitation existed in fuel injection system, frequency of first pressure wave is low and the energy density is high. And there is some high frequency energy in the second pressure wave.