A visualization system, which could realize high-pressure injection under 3 MPa back pressure, was developed to study the spray characteristics of high-pressure common rail diesel engine under high back pressure. Based on this system, the influences of different injection pressures and back pressures on spray characteristics were studied. The experimental results show that, under the same back pressure, the spray angle increases and fluctuates slightly with the injection pressure increase. The spray penetration distance also increases, but its growth is smaller. Under the same injection pressure, the spray penetration distance decreases when the back pressure increases and the change is strengthened under higher injection pressure. In addition, the spray angle increases and fluctuates with back pressure increase, and its fluctuation is more obvious under high injection pressure.%为了探究大背压环境下高压共轨柴油机的喷雾特性,研制了一种可视化喷雾系统,该系统能够实现3 MPa背压环境下的高压喷射.基于该系统,研究了不同喷射压力和背压对高压共轨柴油机喷雾特性的影响.结果表明:同一背压下,随着喷射压力的提高,喷雾锥角逐渐变大,并且存在微小的波动现象,贯穿距离也随之增长,但增长的幅度较小;同一喷射压力下,随着背压的升高,贯穿距离变小,且喷射压力较高时变化幅度较大,喷雾锥角随背压的变大而变大,且存在波动性,在高喷射压力时波动较为明显.
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