In order to get the speed characteristic of engine in misfiring condition, a measuring method for instantaneous speed of engine is researched. The tests are taken on an armored vehicle to simulate the misfire faults in the way of cutting off the fuel, and the instantaneous speed signals are measured in the conditions of normal work, incomplete combustion and misfire. In order to clear the signal noise, the original speed signal is translated into "0-1" series. Fourier analysis is done to show the irregular change of engine speed when engine cylinder is cut out. Furthermore the complexity of the speed signal is analyzed, and K[ ,C] complexity is extracted. The result shows that engine cylinder cut out can be recognized by analyzing the complexity of speed.%为了分析发动机失缸时转速的变化,研究了发动机瞬时转速信号的测取方法,在某型装甲车辆上采用断缸法模拟了失缸故障,测取了发动机正常工作、燃烧不良及失缸工况下的瞬时转速信号.对原始转速脉中信号进行了“0-1”转换,以消除外界噪声干扰.对转速进行了频谱分析,分析了发动机失缸时转速的不规则变化.对转速进行了复杂度分析,提取了K[,C]复杂度特征.分析结果表明,通过转速复杂度分析可以对发动机失缸现象进行判别.
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