Numerical Simulation of the Effect of Fuel Injection Condition on the Diesel and Gasoline Spray Characteristics in a Direct Injection Compression Ignition Engine

In this paper, the numerical simulation of the diesel and gasoline fuels injection in a constant volume chamber is conducted under the operating conditions of a compression ignition engine with openFoam software. In order to check out the possibility of using gasoline instead of diesel to increase the volumetric efficiency of the compression ignition engine and reduction air pollution, the spray characteristics of the gasoline and diesel under injection pressures of 40 and 80MPa, as well as temperatures of 243, 273 and 313K, is investigated. The simulation results are compared with the experimental data derived from fast imaging techniques. The results show that under the same conditions, the vapor penetration length for the two fuels is approximately equal. Also, due to the lower volatility of the diesel fuel, its liquid penetration length in 40 and 80MPa injection pressure was found to be 7 and 9 mm higher than gasoline, respectively, and high volatility of gasoline leads to enough time to make air and fuel mixtures in compression ignition engine. In addition, the reduction in fuel temperature from 313K to 243K resulted an increase in the penetration of gasoline and diesel liquids by 12 and 10 mm, respectively, and decrease in the evaporation rate, which causes a non-homogeneous mixture and an increase in unburned hydrocarbons and emissions.