中文摘要：

针对高压共轨喷油系统在喷油过程中压力波动引起多次喷射稳定性下降的问题,根据系统多次喷射循环喷油量波动特性,建立了系统仿真模型,通过试验验证了模型的准确性。利用所建模型,分别对预-主喷射和主-后喷射中循环喷油量随喷油间隔的波动特性进行研究,分析表明：相同预喷不同主喷时,主喷油量波动幅值随喷射间隔增大而减小,波动周期不随主喷油量增加而变化且波动相位一致,在与整数倍压力波动周期时间差值接近的主喷油持续期内,预主喷射间隔对主喷波动量波动影响规律相似;相同主喷不同预喷时,主喷油量波动幅值随预喷油量增加而增大;相同主喷不同后喷时,随主后喷射间隔增大,后喷油量波动减小,波动周期相同,随后喷油量增加波动幅值变化较小;后喷相同主喷不同时,与整数倍压力波动周期的时间差值相同的主喷持续期,其喷射引起的后喷油量波动规律相似。

英文摘要：

To solve the instability problem, caused by pressure fluctuation during multiple injections of high-pressure common-rail fuel injection systems, we developed a numerical simulation model of the system based on the fluctuation of fuel injection quantity and validated the accuracy of the model by comparing its results with those from experimental measurements. We investigated the fluctuation characteristics of the fuel injection quantity with respect to the variation of the injection interval. The multi-injection modes are the pilot and main injections and the main and post injections. The results show that with the same pilot injection and different main injection, the fluctuation amplitude of the main fuel in-jection quantity decreases with increasing injection interval, and the fluctuation period of the main injection does not vary with increases in the main fuel injection quantity with the same fluctuation phase. In addition, the injection interval has a similar influence on the fluctuation of the main fuel injection quantity when the duration of the main injection approa-ches the time difference of the integer times of pressure fluctuation period. With the same main injection and a different pilot injection, the fluctuation amplitude of the main fuel injection quantity increases with increases in the pilot fuel in-jection quantity. For the same main injection and different post injection, increasing in injection interval between the main and post injections decreases the fluctuation in the post fuel injection quantity, and the fluctuation period of the post fuel injection quantity does not vary. Moreover, the fluctuation amplitude changes slightly with increases in the fuel injection quantity. At the same post injection and different main injection, the injection interval has a similar influence on the fluctuation of the post fuel injection quantity when the duration of the main injection approaches the time differ-ence of the integer times of pressure fluctuation period.