配气相位对小缸径高速柴油机性能影响研究

A Study on the Effect of Valve Phase on the Performance of Small Bore High Speed Diesel Engine

针对新研发小缸径高速柴油机排气温度高引起结构件可靠性下降以及燃油消耗率高造成经济性指标低等问题,通过对原设计方案的换气过程分析研究确定了主要原因为缸内换气不充分残余废气系数大造成燃烧不充分。提出在现有凸轮型线基础上通过优化配气相位解决问题并开展试验验证。结果表明:在保持进气门提前角不变的条件下,通过优化排气门开启角度,在柴油机额定工况下实现了高效快速燃烧,提高了气缸内燃烧效率。柴油机的动力性和经济性有不同程度的提高,其中排气温度降低至619℃,较目标值有8.9%裕度;平均有效燃油消耗率较原方案提高10%。通过试验研究解决了排温高、油耗高的主要问题,满足了技术指标要求,为进一步研究小缸径柴油机性能改进提供了研究方向。

Aiming at the reliability decline and high fuel consumption rate caused by high exhaust temperature of a newly developed small bore high-speed diesel engine,the gas exchanging process of the original design scheme is analyzed and studied,and it’s found that the main reason is that the in-cylinder insufficient exchanging causes the insufficient combustion.The valve phase is optimized on the basis of current cam profile.Test results show that,while the intake valve advanced angle remains,the optimization of exhaust valve angle can help the efficient high speed combustion under rated operation condition,thus improve the in-cylinder combustion efficiency.The power performance and economy of the diesel engine are improved in different degrees,and the exhaust temperature is reduced to 619℃,which is8.9% lower than the target value.The average effective fuel consumption rate is 10% higher than the original scheme.The main problems of high exhaust temperature and high fuel consumption have been solved through the experimental research,and the technical requirements have been met,which provides a research direction for the further research on the performance improvement of small bore diesel engines.