For the problem that occurred during the emission optimization of an electronic control high-pressure common rail diesel engine, the trends of all parameters and the relativity between each parameter and Noχ volume fraction were analyzed based on the test bench repeatability. Furthermore, the verification experiments of ESC variable conditions and constant conditions were carried out. The results show that the small amplitude variation of intake relative humidity, intake mass consumption and diesel temperature has little influence on the Noχ emission measurement of ESC. Under the same experimental conditions, the influence of intake mass consumption on Noχ emission is the largest, the intake relative humidity is following, and the influence on Noχ emission is intensified when both trends are the same. Under little change of engine structure, the main factors that lead to the Noχ difference between different experiments are intake mass consumption and diluted exhaust volume flow and they both have the greater influence on Noχ emission.%针对某电控高压共轨柴油机排放性能优化过程中出现的问题,基于柴油机试验台架的重复性,进行各参数变化趋势分析以及与NOx排放测量的相关性分析.在此基础上,进行了ESC变工况和持续恒工况的试验验证分析.结果表明:进气相对湿度、进气质量流量及燃油温度变化对ESC循环NOx排放测量的影响很小；在相同试验条件下,发动机进气质量流量对NOx排放测量影响最大,进气相对湿度影响次之,二者变化趋势一致时会加剧对NOx排放测量的影响；在发动机结构配置不发生变化的情况下,同工况下多次试验间NOx排放差异较大的影响因素主要为进气质量流量和稀释排气体积流量,二者对NOx排放测量都有较大程度的影响.
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