Numerical Parametric Study of a Six-Stroke Gasoline Compression Ignition (GCI) Engine Combustion- Part II 2020-01-0780

In order to extend the operability limit of the gasoline compression ignition (GCI) engine, as an avenue for low temperature combustion (LTC) regime, the effects of parametric variations of engine operating conditions on the performance of six-stroke GCI (6S-GCI) engine cycle are numerically investigated, using an in-house 3D CFD code coupled with high-fidelity physical sub-models along with the Chemkin library. The combustion and emissions were calculated using a skeletal chemical kinetics mechanism for a 14-component gasoline surrogate fuel. Authors’ previous study highlighted the effects of the variation of injection timing and split ratio on the overall performance of 6S-GCI engine and the unique mixing-controlled burning mode of the charge mixtures during the two additional strokes. As a continuing effort, the present study details the parametric studies of initial gas temperature, boost pressure, fuel injection pressure, compression ratio, and EGR ratio. Focus of this paper is on the impact of these parameters on the performance of the two additional strokes of 6S-GCI cycle such that the extent of controllability of ignition, combustion and energy recovery processes can be understood. The results advocate possible methods of expanding the operating conditions for GCI combustion by governing the mixture stratification and thermal conditions of the charge mixtures.