In order to improve the economy and emissions of the 4190ZLC-2 marine medium speed diesel engine after the electronically controlled reform of the fuel injection system

a multi parameter optimization test was carried out for the fuel injection system. Using the most economical matching parameters obtained by experimental method

the high pressure working process of the engine was simulated by the AVL FIRE software. By the analyses of the 3D flow fields in the combustion chamber

a scheme to further improve the fuel injection pressure and modify the shape of the combustion chamber was put forward and then a better combustion chamber matching scheme was obtained by simulation .Results show increasing the fuel injection pressure can improve the overall performance of the engine. In order to adapt to the increase in fuel injection pressure

the depth and opening diameter of the combustion chamber should be decreased and increased respectively

but the shallow combustion chamber can lead to incomplete combustion

resulting in an increase in fuel consumption. This study can provide a theoretical basis for the improvement of diesel combustion system.