VGT叶片开度对二级增压柴油机高海拔低速匹配特性的影响

基于二级可调增压柴油机高海拔性能模拟试验平台，研究了不同海拔条件下 VGT 叶片开度对高压共轨柴油机二级可调增压系统低速匹配特性的影响。研究结果表明：不同海拔下，随着 VGT 叶片开度的减小，高压级涡轮的涡轮膨胀比和压气机压比、绝热效率逐渐提高，而低压级涡轮膨胀比及压气机效率变化则趋于平缓，因此两级压气机总压比、总效率和总功率的变化趋势与高压级压气机一致；柴油机进气流量及空燃比随着 VGT 叶片开度的减小而增大，动力性及经济性也随之升高；海拔0～4500 m ，高压级压气机匹配状况良好，联合运行线均位于高效率区内。

Effects of VGT Blade Opening on Low Speed Matching Characteristics of Two-stage Turbocharging Diesel Engine at High Altitude

Based on the high altitude performance simulation test system ,the effects of VGT blade opening on low speed matching characteristics of two‐stage turbocharging diesel engine at different altitudes were researched .The results showed that the expansion ratio of high pressure stage turbine and the compression ratio and adiabatic efficiency of compressor increased and that of low pressure stage turbine and the efficiency of compressor changed gently with the decrease of VGT blade opening at different altitudes .Therefore ,the total compression ratio ,efficiency and power of two‐stage compressor were equivalent to those of high‐pressure stage compressor .In addition ,the intake mass flow and air‐fuel radio also increased so that the power and economy performance improved .The high pressure stage compressor had good matching performance at 0‐4 500 m and the joint operating curve was located in a high efficiency area .