CFD Investigation on Injection Strategy and Gasoline Quality Impact on In-Cylinder Temperature Distribution and Heat Transfer in PPC

Recently, internal combustion engine design has been moving towards downsized, more efficient engines. One key in designing a more efficient engine is the control of heat losses, i.e., improvements of the thermodynamic cycle. Therefore, there is increasing interest in examining and documenting the heat transfer process of an internal combustion engine. A heavy-duty diesel engine was modeled with a commercial CFD code in order to examine the effects of two different gasoline fuels, and the injection strategy used, on heat transfer within the engine cylinder in a partially premixed combustion (PPC) mode. The investigation on the fuel quality and injection strategy indicates that the introduction of a pilot injection is more beneficial in order to lower heat transfer, than adjusting the fuel quality. This is due to reduced wall exposure to higher temperature gases and more equally distributed heat losses in the combustion chamber. A comparison was also made between two loads with the same fuel quality and injection strategy, which revealed that even though the relative heat load to the walls was higher in the lower load case, the gross indicated efficiency was higher, due to a lower value of the exhaust energy. (Less)