The coupled experiment of high-low pressure fuel pipe of the DDC 2000 diesel's EUP was conducted;the influences of return fuel of high pressure pipe on feed fuel of low pressure,low pressure fuel pipe on characteristic of high pressure injection were analyzed.The experimented and analyzed results show that if the lOW fuel pressure changes suddenly in the fuel-filled process for EUP,it will increase the cyclic variation of EUP injection characteristics and maybe cause the instability in the jet;with the camshaft speed increasing,the lack of fuel-filled becomes serious;the improved fuel supply pressure of low pressure fuel pipe is helpful to improving fuel supply pressure stability of fuel pump,preventing its abrupt change;the critical fuel supply pressures corresponding to different rotational speeds are different,which increase with the increases of the speeds.%针对DDC2000柴油机用的电控单体泵,进行了电控单体泵高低压油路的耦合实验;分析了电控单体泵燃油系统高压回油对低压油路的供油影响和低压油路对单体泵高压喷射特性的影响.实验与分析结果表明:如果低压油路在单体泵供油过程中出现压力突变将导致高压喷射循环变动较大,产生喷射不稳定;随转速增加,低压油路压力突变的问题趋于严重;提高低压油路的供油压力将有助于改善单体泵的供油过程,防止出现供油压力突变,提高单体泵喷射的循环稳定性;不同转速下对应的临界供油压力不同,该压力随转速提高而增加.
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