To solve the problem of disassembling engine when use tradition method to examine the engine cylinder airproof performance, a non-disassembly online examine method based on engine start electric current is bring forward. After modeling the relationship between diesel's work cycle, start resistance moment, instantaneous rotational speed, voltage and electric current in the engine start time without oil in theory, through synchro sample the signai by the smart DSP inspect node and computation, the validity of the theory model is proved true. To solve the problem of difficult to get the camshaft position reference, a compress TDC index is introduced to find the compress TDC and the fault cylinder can be found. A parameter is introduced to estimate the cylinder obturation coherence. After analyzing the parameter got in nor- mal, gentle gas leak and serious gas leak working condition, these working conditions can be distinguished. This method can find whether or which cylinder has the gas leak fault and how much leak there are in the online non-disassembly condition.%针对传统的发动机气密性检测需要拆卸发动机的缺点,提出了一种基于起动电流的不解体实车在线检测方法.在对发动机不供油起动阶段各缸工作行程、起动阻力矩、瞬时转速、电压和电流的变化规律及相互关系进行了理论建模后,通过柴油机智能检测节点同步采集的实测信号验证了理论模型的正确性.针对F3L912型柴油机提取工作相位难的问题,采用压缩上止点指数来定位压缩行程上止点,进而实现故障缸的定位,并引入了归一化的气缸密闭性参数来判断气缸密闭一致性.在对正常、轻微漏气及严重漏气3种工况下提取的参数进行分析后,证实了提取的参数能够有效区分这些工况.本研究方法在实车在线不解体的情况下实现了发动机气密性故障的定性、定缸和定量判断.
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