可调喷油规律下喷油提前角对柴油机性能的影响

为获取可调喷油规律条件下喷油提前角对柴油机性能的影响规律及成因机理,在实现可调喷油规律喷射的基础上,基于Fire软件建立了柴油机工作过程计算模型,并通过试验对模型中的主要参数进行标定,进而利用模型分析靴形喷油规律下柴油机性能随喷油提前角的变化。结果表明:随着增压时刻的滞后,喷油规律由矩形过渡到斜坡形再到靴形,实现了灵活可调的喷油规律。在靴形喷油规律条件下,存在一个最佳的喷油提前角,使柴油机的动力性和经济性均达到最优。同时,随着喷油提前角的增大,柴油机缸内压力、缸内温度以及放热率均逐渐升高,且到达各自最大值的时刻前移,而NO_x排放量和碳烟排放量则分别呈现增加和减小的趋势。

Effect of fuel injection advance angle on diesel engine performanceunder the condition of adjustable fuel injection law

In order to obtain the effect law and genesis mechanism of fuel injection advance angle on the performance of diesel engine under the adjustable fuel injection law conditions, on the basis of the realization of adjustable fuel injection law injection, the working process calculation model of diesel engine was established by Fire software, and the main parameters of model were calibrated through experiments, then the performance of diesel engine with the fuel injection advance angle under saddle-shaped fuel injection law was analyzed with the model. The results show that with the delay of pressurization time, the fuel injection law changes from rectangle to slope and then to saddle-shaped, which realizes the flexible and adjustable fuel injection law. Under the condition of saddle-shaped fuel injection law, there is an optimal fuel injection advance angle to optimize the power and economy of diesel engine. At the same time, with the increase of fuel injection advance angle, the in-cylinder pressure, in-cylinder temperature and heat release rate of diesel engine increase gradually, and the time of reaching their peak values all move forward, while the NO_x emissions and soot emissions show an increasing and decreasing trend respectively.