二级可调增压共轨柴油机的高海拔燃烧特性

High Altitude Combustion Characteristics of Common Rail Diesel Engine with Two-Stage Regulated Turbocharging System

通过高海拔模拟试验研究了VGT二级可调增压柴油机不同海拔的燃烧特性.结果表明,随着海拔的升高,二级可调增压柴油机的滞燃期延长,速燃期放热率增大,但缓燃期放热率和累计放热量均减小,放热率重心向上止点偏移,缸内平均指示压力下降.与单级涡轮增压柴油机相比,二级可调增压柴油机在高海拔的燃烧状态明显改善;海拔5,500,m时,二级可调增压柴油机平均指示压力提高9.1%,,速燃期放热率峰值降低12.9%,,缓燃期放热率峰值增加2.3%,,累计放热量增大11.1%,,滞燃期缩短11.3%,;标定功率提高11.8%,,燃油消耗率降低4.8%,.

Through high altitude simulation test,the combustion characteristics of common rail diesel engine withVGT two-stage regulated turbocharging system were studied at different altitudes.The results show that with theincrease of altitude,ignition delay lengthens,heat release rate in rapid combustion period increases,but that inslow combustion period decreases,cumulative heat release decreases,the center of gravity of heat release ratemoves closely to the TDC,and the indicated mean effective pressure(IMEP)decreases.Compared with singlestageturbocharging diesel engine,the combustion state of two-stage regulated turbocharging diesel engine isgreatly improved at high altitude.When the altitude is5,500,m,the IMEP of two-stage regulated turbochargingdiesel engine increases by9.1%,,the heat release rate peak decreases by12.9%,in rapid combustion period butincreases by2.3%,in slow combustion period,the cumulative heat release increases by11.1%,,the ignition delayshortens by11.3%,,the rated power increases by11.8%,and the fuel consumption decreases by4.8%,.