The coupling effect of turbulent jet ignition and injection strategy on the combustion performance of a pure methanol rotary engine

Methanol, as an alternative fuel, has significant potential in energy conservation and emission reduction. However, the higher ignition temperature and latent heat of vaporization of methanol fuels also expose engines to the risk of cold-starting difficulties. The turbulent jet ignition (TJI) technology, aimed at enhancing ignition energy, proves effective in improving the ignition and combustion performance of pure methanol. Therefore, this study designed a jet ignition plug to optimize the combustion characteristics of methanol rotary engines. Meanwhile, the influence of injection strategy on the performance of the patterned turbulent jet ignition rotary engine(TJI-RE) was studied for the first time. On this basis, the CFD model of pure methanol TJI-RE was established and validated using relevant experimental data. Results found that the injection angle and position could change in-cylinder fuel distribution during ignition, as well as the quality of fuel entering the pre-chamber, affected by fuel impact position and in-cylinder vortex strength. These factors collectively influenced the combustion characteristics of TJI-RE. Furthermore, the optimal fuel distribution characteristics for TJI-RE included higher fuel concentration in the pre-chamber and increased fuel accumulation in the front of the cylinder Under all calculation conditions, the configuration with the fuel injector positioned 25 mm above the cylinder's long axis and an injection angle of +50 degrees achieved the highest peak pressure and indicated thermal efficiency for TJIRE.