Increasing power density is a promise technical measure for displacement downsize and fuel economy improvement. This paper describes a research into power increase from 73 kW to 150 kW by consecutive combustion process enhancement on a singlecylinder diesel engine with a displacement of 2.8 L. The research was conducted through two steps: The first step was to boost the power output to 92 kW by virtue of increasing intake pressure, reducing intake flow resistance, optimizing cam profile and modifying fuel injection system. The second step was to significantly increase the power to 150 kW by further increasing the intake pressure, raising the engine speed, using an electronic unit pump with a high injection pressure instead of the mechanical pump. The heat release analysis results show that the heat release rate is increased significantly for premixed and diffusion combustion periods. However, the percentage of accumulated heat release during those periods to the total heat release is reduced considerably and hence the percentage of heat release during the late stage of the combustion is obviously increased. How to increase heat release rate during the diffusion combustion period is the main challenge for highly intensified combustion process development.