Combustion Modelling and In-Cylinder Fuel Distribution in a Gasoline Compression Ignition Engine at Varying Speeds

The advanced compression ignition and lean-burn capabilities of a gasoline compression ignition (GCI) engine result in higher thermal efficiency, making it a promising choice for next-generation vehicles. Studies show that gasoline-diesel blend fuelled GCI engines produce lower nitrogen oxides and soot emissions. There is significant interest in the automotive industry in using GCI combustion engines for heavy-duty vehicles; however, this combustion mode needs to be better understood through experimental and simulation studies. Simulation helps understand the in-cylinder fluid flow and combustion dynamics of experimental results. This work aims to model GCI combustion over a range of engine speeds (1500–2500 rpm) and to validate the model against experimental results at a 5-bar brake mean effective pressure (BMEP) engine load. A triple-injection strategy, exhaust gas recirculation (EGR), and preheated intake air were employed to achieve GCI combustion in the test engine. The effect of a narrow-angle injector was investigated to control the wall impingement of the test fuel. The simulation results revealed that the fuel parcels from pilot injections caused wall wetting, while others were trapped in the squish regions. Most fuel droplets evaporated before the combustion onset, supporting the concept of partially premixed combustion. The narrow injection angle of the fuel spray directed more fuel into the piston bowl, reducing combustion efficiency.