Research on Combustion and Emission Characteristics of Hydrogen/Diesel Dual Fuel Engines at Different Altitudes
Based on the comprehensive test system of atmospheric simulation,the combustion and emission characteristics of hydrogen/diesel dual fuel engines at different altitudes were studied by simulating the atmospheric pressures at the altitudes of 0 m,1 000 m and 2 000 m.The results show that with the increase of hydrogen substitution rates,the premixed combustion is enhanced,the combustion speeds and the peak pressures in the cylinder are increased,and the corresponding phase is advanced at different altitudes.With the increase of hydrogen substitution rates,soot and CO emissions decrease first and then increase,NOx emissions increase,and CO2 emissions decrease.As the altitude increases,the excess air coefficients decreases,and the effective thermal efficiency decreases.When the engine speed is 1 600 r/min,the premixed combustion is weakened,the peak pressure of the engine cylinder decreases,and the corresponding phase is delayed with the increase of altitudes.When the CO emissions are the lowest,the soot emissions at the altitudes of 1 000 m,2 000 m increase by 44.44%and 127.78%respectively,the CO emissions increase by 8.95%and 16.86%respectively,and the CO2 emissions increase by 4.34%and 16.86%respectively,compared with these at the altitude of 0 m.The increase rates of soot and CO2 emissions increase with the increase of altitudes.When the engine speed is 3 000 r/min,as the altitudes increase,the peak cylinder pressures increase slightly,the corresponding phase of the peak cylinder pressure is advanced,and the premixed combustion is enhanced.As the altitudes increase,the emissions of soot,NOx,CO and CO2 increase,and the increase rates of emissions increase.When the soot emission is the lowest with the increase of altitudes,soot emissions at the altitudes of 1 000 m,2 000 m increase by 18.67%and 56.04%respectively,NOx emissions increase by 14.78%and 38.40%respectively,CO2 emissions increase by 7.29%and 15.80%respectively,compared with these at the altitude of 0 m.When the CO emission is the lowest,and the CO emissions at the altitudes of 1 000 m,2 000 m increase by 24.53%and 62.87%respectively,compared with these at the altitude of 0 m.
万方数据
维普
