| Numerical simulation and experimental investigation are applied in this paper. The effects of the combustion system parameters on the fuel-air mixture formation, diesel engine performance, combustion process and exhaust emissions are studied. A working process computational model as well as a CFD numerical model is established. A valve train profile design software is developed. The optimization process is conducted on YC6M220 turbocharged diesel engine, and a combustion system parameter optimization scheme is obtained. This paper explores a new method to match and optimize the diesel engine combustion system. Theoretical analysis and experimental investigation are combined in this method.Firstly an AVL-BOOST cycle model is developed. The effect of valve train system on engine performance is investigated. Combining the valve train profile design software, the valve train profile is optimized, and experimental results validate that the engine performance is improved. Experimental investigation is performed on turbocharger. The effects of different intake mass flow rates and pressure ratios on fuel consumption and emissions are studied, and optimization process is conducted on turbocharger. Experimental investigation is also performed on cylinder heads with different intake swirl ratios, and the effect of intake swirl on engine performance is studied. The cylinder head with the intake swirl ratio of 1.7 is selected as the optimized scheme. Four combustion chambers with different geometry parameters are designed. A CFD numerical code STAR-CD is applied to investigate the in-cylinder turbulence flow, fuel-air mixture formation and distribution. The effect of combustion chamber geometry on combustion process, NOx and PM formation is studied, and there are comparisons between numerical and experimental results. Experimental study is also carried out to investigate the effect of combustion chamber geometry and fuel supply...
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