无节气门汽油机质调节负荷控制特性研究

Study on load control characteristics of gasoline engine quality regulation without throttle

采用歧管喷射燃油质调节负荷控制方式,研究无节气门小排量单缸汽油机的负荷控制特性。通过对改造无节气门汽油机开展对标原机动力性的负荷控制喷油标定,采用多目标优化方法得到全工况最佳燃空比和点火提前角控制参数MAP图,结合三维数值模拟对比分析无节气门汽油机质调节负荷控制对缸内流场及燃烧过程的影响特性。结果表明:与带节气门原机相比,在3000 r/min最大扭矩转速,30%节气门开度负荷工况,无节气门汽油机有效燃油消耗率降低20.1%,指示热效率提高24.9%,缸内循环平均湍动能增加,且中小负荷工况能燃用更稀薄混合气,但会导致火焰传播速度变慢,燃烧持续期延长,使NO_(x)和HC排放增加。

Manifold injection fuel quality adjustment is used as the load control method,and the load control characteristics of a small displacement single-cylinder gasoline engine without throttle are studied.By carrying out the load control fuel injection calibration for the modified unthrottled gasoline engine,the multi-objective optimization method is used to obtain the best fuel-air ratio and advance angle of ignition control parameter MAP diagram for all working conditions,combining three-dimensional numerical simulation to compare and analyze the characteristics of the influence characteristics of the unthrottled gasoline engine quality adjustment load control on the flow field and combustion process in the cylinder.The results show that,compared with the original engine with throttle of the same power,under 30%throttle opening load condition of maximum torque speed 3000 r/min,the effective fuel consumption rate of unthrottled gasoline engine is decreased by 20.1%,the indicated thermal efficiency is improved by 24.9%,and the average turbulent kinetic energy of the circulation in the cylinder also is increased.The unthrottled gasoline engine can burn a leaner mixture under medium and small load conditions,but it will slow down the flame propagation speed,prolong the combustion duration,and increase NO_(x) and HC emissions.