Research on the structure of pre-chamber and jet orifice of a turbulent jet ignition rotary engine fueled with methanol/gasoline blends

This study used both methanol fuel and turbulent jet ignition (TJI) mode to improve the combustion and emission performance of a gasoline rotary engine (RE). Further, in order to research the combustion process of the turbulent jet ignition rotary engine (TJI-RE) fueled with methanol/gasoline blended fuel in depth, the experimental bench and numerical simulation model were established respectively. Moreover, the reliability of the numerical simulation model was verified by the experiments. Eventually, based on the numerical simulation model, the effects of the volume ratio of pre-chamber (VR-PC) and the length diameter ratio of jet orifice (LDR-JO) on the in-cylinder flame propagating were studied. The study results showed that for any fixed LDR-JO, increasing VR-PC could provide higher ignition energy for the cylinder. But the timing of the jet flame entering the cylinder, meanwhile, would be delayed. Therefore, considering the "trade-off" relationship between ignition energy and the timing of jet flame entering the cylinder, VR-PC is recommended to be 2.2%. For any fixed VR-PC, increasing LDR-JO could increase the injection speed of jet flame. But the cross-sectional area of the jet flame at the outlet of the jet orifice, meanwhile, would become smaller. Therefore, considering the "trade-off" relationship between the injection speed of jet flame and the cross-sectional area of the jet flame at the outlet of the jet orifice, LDR-JO is recommended to be 2.5. Additionally, for TJI-RE fueled with methanol/gasoline blended fuel, the higher the in-cylinder peak pressure, the more sufficient the combustion, and the lower the CO emission. And the trend of NO emission was opposite to that of CO emission.