Study on effect of heat transfer space non-uniformity of combustion chamber components on in-cylinder NOx emission formation in internal combustion engine

The components of combustion chamber (cylinder head-cylinder liner-piston assembly-oil film) were taken as a coupled body.Based on the three-dimensional heat transfer numerical simulation of the coupled body,a coupled three-dimensional calculation model for in-cylinder working process and the combustion chamber components was built with domain decomposition and boundary coupled method,which implements the coupled three-dimensional simulation of in-cylinder working process and the combustion chamber components.The model was applied in the influence investigation of the space non-uniformity in heat transfer among combustion chamber components on the generation of in-cylinder emissions:NOx.The results showed that the heat transfer space non-uniformity of combustion chamber components directly influences the formation of in-cylinder NOx.The main area being influenced was the accessory area on the wall,while the influence on the generation of NOx in the central area couold be omitted.

The components of combustion chamber （cylinder head-cylinder liner-piston assembly-oil film） were taken as a coupled body. Based on the three-dimensional heat transfer numerical simulation of the coupled body, a coupled three-dimensional calculation model for in-cylinder working process and the combustion cham- ber components was built with domain decomposition and boundary coupled method, which implements the coupled three-dimensional simulation of in-cylinder working process and the combustion chamber components. The model was applied in the ilfluence investigation of the space non-uniformity in heat transfer among combustion chamber components on the generation of in-cylinder enfissions ： NOx. The results showed that the heat transfer space non-uniformity of combustion chamber components directly influences the formation of in-cylinder NOx. The main area being influenced was the accessory area on the wall, while the influence on the generation of NOx in the central area couold be omitted.