Performance Simulation And Parameters Calibration Of Gasoline Blended With Dissociated Methanol Gas Combustion In Si Engine

With the increasing of car ownership, the continuous lack of oil resources and the deteriorating atmospheric pollution along with them, looking for clean alternative fuels is of great significance. The hydrogen and carbon monoxide produced by catalytic pyrolysis of methanol. The use of dissociated methanol gas and fuel burning, can help to improve the combustion efficiency and reduce the pollution of the engine. Our Country is rich in coal resources, has a mature technology for the use of coal to produce methanol, providing a strong guarantee for the supply of methanol, methanol as a clean alternative fuel has broad prospects.A certain type of gasoline engine as the research object, the simulation model was established and the parameters were calibrated based on GT-POWER. The torque and fuel consumption rate of external characteristics and the cylinder pressure curve under partial load were simulated and experimental comparative analysis, The results show that the error between simulation results and the experimental data less than 5%, which meet the requirements of simulation analysis. On the basis of the analysis characteristics of dissociated methanol gas, the calculation formula of equivalent air fuel ratio was derived based on the hypothesis model, which provides a theoretical basis for the relevant parameters of the simulation model.Simulation results show that: at the full load compared with the original engine, the power of engine fueled with methanol is increased, while the power of engine fueled with ideal dissociated methanol gas is decreased. The equivalent fuel consumption rate of engine fueled methanol and ideal dissociated methanol gas both increased. Under part load, keep dissociated methanol gas replacement ratio unchanged, with the increase of methanol cracking rate, the gradual reduce of the power of the engine, but cylinder pressure is rised, the fuel heat release is advanced, the combustion condition is improved. When the methanol cracking rate remain constant, with the increase of methanol cracking gas replacement ratio, the engine power is reduced, but the cylinder pressure is increased, and the burning rate of the mixture accelerated. Under partial load, keep the methanol cracking rate unchanged, with the excess air coefficient increases, the engine power is reduced, but the effective thermal efficiency is increased first and then decreased, in the specific dissociated methanol gas replacement ratio, with the excess air coefficient increases. NOx emission is increased first and then decreased, therefore adding the dissociated methanol gas and using lean burn mode can effectively reduce NOx. Under partial load and keep the methanol cracking rate unchanged, with the dissociated methanol gas replacement ratio increases, the optimal ignition advance angle is decreased, In particular methanol cracking gas replacement ratio, with the ignition advance angle increase, the cylinder pressure is increased, the mixture combustion in advance and the cylinder temperature is increased, NOx is increased rapidly with the increases of ignition advance angle.At the end of this paper, under the specific condition, dissociated methanol gas replacement ratio is 20%, the control parameters of engine were calibration on the test bench, and getted the basic fuel injection pulse MAP diagram and ignition advance angle MAP diagram, providing the basis for the optimization of the engine in the future.