CFD Simulation of Mixture Formation and Combustion Processes in a Direct-Injection Gasoline Engine Using a GTT Code

In order to numerically simulate the mixture formation and combustion processes in a direct-injection gasoline engine, the validity of the submodels for fuel spray and combustion was investigated. The physical model proposed by the authors was employed for hollow-cone sprays injected from a swirl injector along with the authors' original submodels. This hollow-cone spray model was validated by comparing the calculated and measured results of the behavior of hollow-cone free spray. As a combustion model, Reitz's model was employed. These submodels were incorporated into the authors' GTT code, and the mixture formation and combustion processes in a direct-injection gasoline engine were numerically analyzed using this code. The validity of the submodels was confirmed by comparing the calculated results of the temporal variation of fuel vapor concentration and gas pressure in the cylinder with the experimental ones under various operating conditions of stratified charge combustion. As a result, it has been found that the mixture formation and combustion processes in the engine can be simulated reasonably well with the present submodels.