可变喷油速率的超高压共轨系统喷射控制研究

通过AMESim软件建立了喷油速率可调的超高压共轨系统仿真模型,分析了相同喷油量条件下喷油率的变化特点。采用GT-Power软件建立单缸柴油机模型,将不同喷油率导入柴油机的燃烧计算模型,研究了不同喷油率对柴油机缸内压力、缸内温度、放热率、NO_x排放、碳烟排放及输出转矩和油耗率的影响。仿真结果表明:靴形喷油速率匹配合适的喷油提前角可优化柴油机的综合性能。搭建了超高压共轨柴油机台架,开展了不同喷油速率的喷射控制试验,结果表明:与相同油量条件下的高压共轨喷射相比,柴油机实施变喷油速率超高压喷射可获得更优异的动力性和燃油经济性,动力输出提高了5%,燃油消耗量下降了6%,碳烟排放降低,但NO_x排放升高。

Research on Injection Control of Ultra High Pressure Common Rail System with Variable Fuel Injection Rate

A simulation model of ultra high pressure common rail system with variable fuel injection rate was established by AMESim software, and the characteristics of the fuel injection rate under same injection quantity were analyzed. Using the combustion model of a single cylinder diesel engine built by GT-Power software, the different fuel injection rate was inputted into the engine model to research the effect of different fuel injection rates on cylinder pressure, cylinder temperature, heat release rate, exhaust emissions, torque and fuel consumption. Simulation results show that the comprehensive performance of the engine can be optimized by matching a saddle-shaped injection rate with an appropriate fuel injection timing. At the same time, the injection control experiment with different fuel injection rate was carried out on a test bench. Experimental results show that: compared with the same fuel quantity of high pressure common rail injection, the ultra high pressure fuel injection with variable injection rate can be used for diesel engine to obtain more excellent power performance and fuel economy. This will make the power output increased by 5% and the fuel consumption decreased by 6% with higher NOx emissions and lower soot emissions. The research conclusions can help to explore the fuel injection law, thus improving the engine performance.