Reducing heat losses is very important to improve thermal efficiency in diesel engines. There are some methods to reduce heat losses, such as adiabatic engines, restricted flow with highly dispersed spray, heat insulation coatings and so on. Multiple injection strategy is one of the most effective approaches to reduce heat losses because it doesn’t need additional engine components. The present study investigated the effects of multiple injection on the heat losses in a passenger’s vehicle diesel engine by using single-cylinder test engine and 3D-CFD code.