Based On The KIVA Variable Parameters Of Conventional Diesel Engine Emissions Research

With the increasingly serious environmental pollution, increasingly stringent emission regulations, how to further reduce diesel emissions has become the most important issue now. Diesel has been widely used in the power plant for its high power and low fuel consumption, the major conventional diesel emissions have NOX, HC, CO and SOOT. Due to the continuous development of computational science and increase computing capacity, Numerical simulation has become an important means of the combustion process. It is time-consuming short, low cost, can get a lot of the flow field information that can not come from trial.In this paper, taking KIVA as the research tool. Using the pre-processing module of KIVA software to establish the geometric model of 4102 diesel engine combustion chamber, and determining the initial and boundary parameters for the calculation, Then the numerical simulation, the simulation results and experimental results are in good agreement, indicating the combustion model is real viable.Analysis of the different effects of EGR on combustion and emissions of diesel engine, in order to determine the impact of differences in CO2, H2 O and N2, using them to compensate for reducing the amount of oxygen in order to maintain the total amount of intake air,conducted EGR rate of 3%, 6%, 9% three conditions of the nine simulation. The results show that the impact of three diesel engine cylinder combustion gases and HC, NOX, CO and SOOT pollutant emissions roughly the same: With EGR amount increases, the maximum cylinder pressure and the maximum combustion temperature showed a downward trend, the peak position which is closer to the compression top dead center, and shorten the duration of high-temperature, with the increase of EGR rate the combustion starting point move backwards; the HC Eventually emissions increased; the NOX emissions decreased significantly; the CO emissions decreased; the SOOT emissions eventually increases; but the final value is not the same, the exhaust gas was found to play a major role in its recirculation or dilution effect, and chemical and thermal effects play a smaller role.Analysis of the different load effects on combustion and emissions of diesel engine, found that with the load(fuel injection quantity)increased, the average of cylinder pressure and temperature will gradually increase, the maximum explosion pressure and maximum combustion temperature also increase, the peak of the curve gradually away from TDC; the final emissions of pollutants of HC, NOX, CO and SOOT is also increase.Analysis of the different influence of fuel injection timing on combustion and emissions of diesel engine. Found that the maximum explosion pressure and the maximum combustion temperature in cylinder increases with the increase of fuel injection advance angle, and the position of the peak more closer to the check point on the compression, the combustion start point as the fuel delivery advance angle moved forward and advance, the duration of high temperature growth; HC eventually emissions decreases with the increase of fuel injection advance angle; NOX generation also increase; CO emissions eventually increases; However, the trend of SOOT emissions is reduced.