共轨系统多次喷射油量波动与轨压的关系

Relationship between Multi-injection Oil Mass Deviation of Common Rail System and Rail Pressure

高压共轨系统进行多次喷射时,前一次喷射引起的高压油管内燃油压力波动会导致后一次喷射的喷油量出现偏差。在两个不同的第1次喷射脉宽下,研究轨压对两次喷射中第2次喷射油量波动幅度的影响。结果表明,轨压对第2次喷射油量波动幅度的影响因第1次喷射脉宽的不同而呈现出不同的规律。分别在两个喷射脉宽下研究轨压对单次喷射引起的压力波动幅度的影响。结果显示,小脉宽下,轨压对单次喷射引起的压力波动幅度的影响规律与轨压对第2次喷射油量波动幅度的影响规律相同,但大脉宽下的影响规律稍有不同。讨论轨压对油量波动幅度的影响机理,提出喷油时间波动系数,该系数说明轨压对第2次喷射喷油量波动的影响机理,得到轨压对喷油量波动幅度的影响规律。

Oil pressure fluctuation caused by last injection can lead to oil mass deviation of this injection during multi-injection of high pressure common-rail system.Influence of rail pressure on the oil mass deviation amplitude of the second injection under two different injection pulse width of the first injection is researched.The results show that the changing of oil mass deviation amplitude with rail pressure shows different law under different injection pulse width of the first injection.The influence of rail pressure on the amplitude of pressure fluctuation caused by a single injection is also studied under two different injection pulse width.The results show that the influences of rail pressure on the oil mass deviation amplitude and pressure fluctuation amplitude are almost the same when the injection pulse width is small,but there is a difference when the injection pulse width is large.Mechanism of the influences of rail pressure on oil mass deviation amplitude is discussed in detail.A coefficient named injection time deviation coefficient which demonstrates the mechanism of the influence of rail pressure on oil mass deviation is put forward.The influence law of rail pressure on oil mass deviation amplitude is acquired.