喷油策略对柴油机高原起动过程性能影响研究

Influences of Fuel Injection Strategies on the Starting Performance of A Diesel Engine at High Altitudes

基于高原环境模拟装置,以单缸柴油机为试验对象,进行了0~4000 m海拔起动性能试验,研究了喷油策略对柴油机变海拔起动性能的影响。结果表明,海拔从0增至4000 m的过程中,起动升速期和过渡期时间分别延长14.2%、15.8%。平原工况下,随着轨压的提高,过渡期先增加后降低,但升速期逐渐降低,起动总时间缩短。海拔4000 m时,过渡期与升速期均随轨压先增加后降低。在平原工况下,采用阶梯型喷油策略能够有效缩短过渡期,减少起动时间,起动时间较原机策略缩短6.1%,提高过渡转速能够抑制转速上冲,缩短起动时间。当海拔为4000 m时,增加初始阶段循环喷油量及过渡转速均能缩短过渡时间,改善起动性能。

An experimental study was conducted to investigate the effect of fuel injection strategy on the performance of diesel engines during starting process at different altitudes.The tests were carried out on a single diesel engine with a plateau simulator to stimulate altitudes from 0 to 4000 m.The result shows that as the altitude increases from 0 to 4000 m,the transition time and speed-up time of the diesel engine in starting process are prolonged by 14.2%and 15.8%,respectively.Under plain conditions,with the increase of rail pressure,the transition time decreases,and the total starting time shortens.At the altitude of 4000 m,the transition time and speed-up time both increase first and then decrease with the rail pressure.The fuel injection quantity change with the speed step can reduce the speed transition time and increase the speed-up time during starting process under plain conditions,and the total time is 6.1%shorter than that under the original engine working condition.Increasing the transition speed can inhibit the speed upsurge and shorten the start time.At the altitude of 4000 m,increasing the initial stage of cycle fuel injection quantity and transition speed can significantly improve the starting performance.