Investigation on the Combustion Characteristics and Pre-Chamber Injection Strategy of the Methanol Engine by Turbulent Jet Ignition

The engine performances and combustion characteristics of a turbulent jet ignition（TJI） methanol engine were investigated based on a four-stroke single-cylinder engine. The results show that， the heat release rate （HRR） of TJI combustion mode shows the “double-peak” phenomenon， and the HRR peak is higher than that of spark ignition（SI） mode. Meanwhile， the combustion duration of TJI combustion mode is shorter. When the excess air coefficient λ is 1.0， the TJI combustion mode with passive pre-chamber that the methanol was fueled in the pre-chamber has a lower indicated mean effective pressure（IMEP） in comparison to SI mode， and the indicated specific fuel consumption （ISFC） of TJI combustion mode with passive pre-chamber is slightly higher than that of SI mode. For the TJI combustion mode with active pre-chamber， when the excess air coefficient λ is 1.5， the TJI methanol engine has a superior combustion stability when injection timing of pre-chamber methanol is -180° in crank angle and the injection pulse width is 350 μs~600 μs. Meanwhile， both the power performance and fuel economy are improved.