Study On The Process Of Combustion And Emission Characteristics Of Diesel Engine In Ar/O₂ Intake Condition

With the strengthening of energy saving and protect the environment consciousness, and the strict emission regulations, people begin to pay attention to the problem of trade-off between NOx and soot. In order to solve this problem, the diesel engine emissions to meet increasingly stringent emission regulations, diesel engine were studied in Ar/O2 intake conditions. Firstly, the combustion process and emission characteristics of diesel engine numerical simulation in different proportion of Ar/O2, and then according to the results of simulation experiment scheme is designed, Finally, through the experimental study on combustion process and emission characteristics of diesel engine in Ar/O2 intake conditions. Specific works of this paper are as follows:The thermal efficiency and combustion thermochemistry are theoretically analyzed in Ar/O2 intake conditions. The specific heat ratio of Ar/O2 shows that the thermal efficiency of engine in Ar/02 intake is higher than the thermal efficiency of engine in air intake, and with the increase of Ar ratio in Ar/O2 mixture the thermal efficiency is increased. The combustion thermochemical analysis, the actual mixture fuel ratio, the actual oxygen fuel ratio and the actual excess mixture coefficient in Ar/02 intake is higher than that in air intake.Then the ZS195 diesel engine was numerically simulated by using AVL Fire software. The average temperature and the average pressure of Ar/O2 intake conditions is higher than the average temperature and the average pressure of air intake conditions, and with the increase of Ar ratio in Ar/O2 mixture, the average temperature and the average pressure are also higher. In the 0.21O2+0.79Ar intake conditions, with the advance of the injection advance angle, the average pressure and the average temperature is also higher and higher. NO, CO and CO2 emissions of Ar/O2 intake conditions are lower than the emissions of air intake condition, with the increase of O2 ratio in Ar/O2 mixture, NO, CO and CO2 emissions are lower and lower.Finally through the bench test to study the effect of combustion process and emission characteristics of ZS195 diesel engine in different proportion Ar/O2 intake and different load. The combustion process and emission characteristics of Ar/02 intake condition are better than that of air condition; Dynamic performance of the engine is highest in 0.3O2+0.7Ar intake under different proportion Ar/O2 intake, with the increase of O2 ratio in Ar/O2 mixture engine performance is relatively lower, at the same time the soot, HC and CO emissions lower and lower, and no NOx emission of diesel engine in Ar/02 intake conditions. Combustion process and emission characteristics of diesel engine in 0.21O2+0.79Ar intake are better than that in air intake under different loads; With the increase of load the Dynamic performance of diesel is higher and higher, at the same time soot, HC and CO emissions are relatively high.