Study on warm start mode of gasoline direct injection engine

Three start modes such as traditional start mode, start mode with compression cylinder combustion and start mode assisted with expansion cylinder combustion were investigated on a gasoline direct injection (GDI) engine. Speed characteristics, HC emission and power consumption during starting process were analyzed comparatively. Compared with the traditional start mode, the start mode with compression cylinder and start mode assisted with expansion cylinder combustion have many advantages in terms of starting speed and starting power consumption, especially the latter almost saves half of start power consumption. HC emission of start mode with the compression cylinder combustion hardly increases, while HC emission of the start mode assisted with expansion cylinder combustion increases to some degree because of its bad combustion in expansion process. Integrative advantages of the start mode with compression cylinder combustion are more relatively.