基于时频分析探究点火对煤油发动机爆震的影响

在一台自主研发的活塞式航空煤油发动机上,基于瞬时放热率对爆震燃烧进行时频分析,探究了双火花塞点火策略对航空煤油发动机爆震燃烧的作用效果。试验结果表明,此款发动机在8.2~14.8 kHz频带内的放热率过高导致爆震燃烧的发生,推迟同步相位点火提前角降低了此频带内的瞬时放热率,从而抑制爆震;增大异步点火相位差能够逐渐降低发动机的爆震指数(KF)和爆震特征频带内的瞬时放热率;提高点火能量会略微增大爆震倾向,但在一定程度上可以提高发动机的动力性。 

Effect of ignition on detonation combustion of kerosene engine based on time-frequency analysis

Based on the instantaneous heat release rate, the time-frequency analysis of knock combustion was carried out on a self-developed piston-type aviation kerosene engine. The influence of the dual-spark ignition strategy on knock combustion was investigated. The result showed that the excessive heat release rate of the engine in 8.2-14.8 kHz frequency band led to knock combustion. Delaying synchronous phase ignition advance angle reduced the heat release rate in the major frequency band and inhibited knock. With the increase of the asynchronous ignition phase difference of the dual-spark ignition, the knock factor (KF) and the heat release rate in the major frequency band decreased gradually. Increasing ignition energy led to a slight increase in the knock tendency, but it can improve the power performance of the engine to some extent.