关键词: 动力机械工程, 缩口型燃烧室, 涡流强度保持性, 进气涡流, 优化匹配, 排放

Abstract: The concept of swirl intensity retention(SIR) was introduced to evaluate quantitatively the transient flow characteristics of the air in the lowemission reentrant combustion chamber. The air flow field and its evolution in the reentrant combustion chamber of an automotive heavyduty direct injection diesel engine was simulated by the software FIRE. The SIRs for the combustion chamber with different reentrant diameters were calculated by the software MATLAB from the simulation data and the effects of the reentrant diameter on the flow characteristics in the combustion chamber and their SIRs were analyzed. On this basis, the concerted effects of the SIR with the fuel injection system parameters and the intake air swirl ratio on the diesel engine performance were studied on a dynamometer test bench. The results show that the designed properly reentrant combustion chamber can effectively organize and control the air flow field history in the chamber, and there are the optimized fuel injection spray orientation and location relative to the chamber and the optimized intake swirl ratio for this kind of combustion chamber, so can improve the engine emissions without penalty on its performance.

Key words: power machinery and engineering, reentrant combustion chamber, swirl intensity retention, intake swirl, optimization matching, emissions