通过对柴油机独立减压缓速、排气缓速性能进行研究，获取了二者在循环工作过程中的作用区域和性能提升的影响因素，并以此为基础，组合二者最优方案形成了复合缓速系统，进一步分析独立缓速性能改进方法在复合缓速中的适用性，通过试验验证了改进策略的有效性。研究结果表明，复合缓速是一种有效的辅助缓速装置，合理匹配后可在柴油机运转转速范围内获得与柴油机标定功率相等的制动功率，同时柴油机排温仍然可控制在限值范围内。

The influencing factors of action area and performance promotion for dropping pressure and exhaust braking during the working process
were acquired, the compound braking system was then formed, the applicability of independent retarding performance in compound braking was further
researched, and the effectiveness of improvement strategy was finally verified.The results show that compound braking is an effective braking method. The
reasonable matching can help diesel engine to get the same brake power as rated power in the operating range and the exhaust temperature is still lower than
the limit.