The present paper is a contribution in which is used a numerical simulation approach, the Virtual Engine Model, to study the combination of the Compression Ignition process with a Gasoline Direct Injection mixture preparation in a limited number of load-points.
The first part of the paper describes the reasons for which current Gasoline Direct Injection engine technology must be combined with other technologies related to the in-cylinder mixture preparation control to further increase their potential for decreased fuel consumption.
The paper continues with a description of the physics of spark and compression ignited processes as well as of the involved mixture preparation hardware components. The setup and the practical use of the Virtual Engine Model are discussed for both spark and compression ignited approaches.
The optimization by the virtual engine model approach enables a redesign of the fuel injector atomizer and the injection strategy, which produces compression ignited combustion performance in the studied load points at acceptably low torque fluctuations. At the load points this performance is obtained at higher λ-values, but at decreased NOX formation levels compared to the original SI-based combustion.
The paper concludes with a real engine test rig experimental verification of the impact obtained from application of the optimized parameter configuration suggested by the Virtual Engine Model analysis.