【摘要】 在一台经改造的发动机上开展了不同进气温度下不同高辛烷值基础燃料(PRF)的均质压燃台架试验,利用离散小波变换方法从缸内压力中提取了爆震信号,定义了爆震强度(pKI),确定了爆震门槛值(pKIe)为0.2 MPa,当某个循环的pKI大于0.2 MPa时,定义为该循环发生爆震。对所研究的3种高辛烷值燃料,进气温度和辛烷值的变化对pKIe的值没有影响。对于轻微爆震的情况,利用提出的方法比使用最大压力升高率方法能更准确地判定爆震的出现,HCCI爆震燃烧存在着明显的边界,是一个突变过程。更多还原

【Abstract】 Experiment on homogeneous charge compression ignition(HCCI) combustion with primary reference fuels(PRF) of different octane numbers at different intake air temperatures was carried out on a modified engine.In this paper,knock signal was extracted from in-cylinder pressure signal with discrete wavelet transfer(DWT) method and pKI value was defined as knock intensity.Knock intensity threshold(pKIe) was also determined.Knock occurring is regarded when pKI is larger than 0.2 MPa.pKIe is a constant under different intake air temperatures and different fuels in this experiment.The study showed that the defined knock intensity could give precise judgement for a light knock comparing to the method of maximum rise rate of in-cylinder pressure.The research demonstrates that HCCI knocking combustion is a drastic changing process and has a clear boundary.更多还原