二级增压系统压气机效率的优化策略研究

对配置在1台重型车用柴油机上的二级增压系统进行了性能研究。结果表明:放气阀开启的二级增压系统存在进气能力不足、压气机效率低的问题;关闭二级增压放气阀后,在中、低转速低负荷工况仅采用高压级增压器,而其余工况借助高压级涡轮旁通阀实现进气压力可调,增压系统压气机效率均可超过60%,且最大进气压力可达334kPa;针对不同工况采用不同增压形式,通过控制涡轮旁通阀开度使二级增压系统进气压力及压比分配得到有效调节,可以改善压气机效率及燃油经济性,为二级增压系统与重型柴油机的性能匹配提供技术参考。

Optimization Strategy of Compressor Efficiency for Two-stage Turbocharging System

The performance of a two-stage turbocharging system equipped on a heavy-duty diesel engine was studied .The re-sults show that the two-stage turbocharging system opened by air bleed valve has the problems of pressure boost deficiency and low compressor efficiency . The compressor efficiency can surpass 60% and the maximum intake pressure may increase to 334 kPa by using the high pressure stage compressor in low load at medium and low speed and adjusting the intake pressure with high pressure stage turbine bypass valve in the remaining conditions after closing the air bleed valve .According to differ-ent supercharging forms under different working conditions ,the intake pressure and pressure ratio distribution of two-stage turbocharging system is effectively adjusted by controlling the opening of turbine bypass valve .Accordingly ,the compressor ef-ficiency and fuel economy improved ,which provided the reference for performance matching between heavy-duty diesel engine and two-stage turbocharging system .