A three-phase sequential turbocharging system with two unequal-size turbochargers is developed to improve the fuel economy performance and reduce the smoke emission of the automotive diesel engine, and it has wider range of application than the current two-phase sequential turbocharging system. The steady matching method of the turbochargers and engine and the steady switching boundary are presented. The experimental results show that this system is effective to improve the engine performance especially at the low speed and high load. The maximum reductions of BSFC and smoke opacity are 7.1% and 70.9%. The optimized switching strategies of the valves are investigated, and the surge of the compressor in the switching process is avoided. The switching strategies in the accelerating process are optimized, and the acceleration time from 900 r/min and 2100 r/min at constant torque is reduced by approximately 20%.
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机译：开发了具有两个不等大小的涡轮增压器的三相顺序涡轮增压系统，以提高燃油经济性并减少汽车柴油机的烟尘排放，并且与当前的两相顺序涡轮增压系统相比，其应用范围更广。提出了涡轮增压器与发动机的稳态匹配方法以及稳态切换边界。实验结果表明，该系统可有效改善发动机性能，特别是在低速和高负荷下。 BSFC和烟气不透明度的最大降低分别为7.1％和70.9％。研究了阀门的最佳切换策略，避免了压缩机在切换过程中出现喘振现象。优化了加速过程中的切换策略，将恒转矩下900 r / min和2100 r / min的加速时间减少了约20％。
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