Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained...Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained. A computer program for simulating the piston second order motion was conducted to calculate the lateral motion of the upper part and the bottom part of piston skirts of the engine of automotive model CA1091. From the simulated result, the maximal impacting phase and the maximal impacting region of the piston were obtained. The result can be used for designing engine, diagnosing the noise of piston knocking cylinder wall and explaining many practical fault phenomena in theory.展开更多
A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process o...A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process of aviation kerosene was studied using this model. The research results showed that under the working conditions of 5500 r/min and 50% throttle opening, as the ignition energy increased, the peak values of average cylinder pressure and average temperature increased, and the combustion duration shortened, The advance of the combustion center of gravity increases the tendency of the engine to knock. Under the same operating conditions, as the ignition timing advances, the peak values of average pressure and average temperature in the cylinder increase, gradually approaching the top dead center, and the tendency of engine detonation increases more significantly.展开更多
活塞敲击噪声是柴油机最重要的机械噪声,控制敲击噪声一般可以从源、传递途径以及表面辐射3方面考虑,其中控制源效果最佳。基于活塞2阶运动理论建立活塞运动动力学方程,计算得到活塞与缸套间隙别为0.5 mm、1.0 mm和1.5 mm 3种工况下的...活塞敲击噪声是柴油机最重要的机械噪声,控制敲击噪声一般可以从源、传递途径以及表面辐射3方面考虑,其中控制源效果最佳。基于活塞2阶运动理论建立活塞运动动力学方程,计算得到活塞与缸套间隙别为0.5 mm、1.0 mm和1.5 mm 3种工况下的活塞与缸套4个接触点位置的载荷力。建立柴油机有限元模型,基于时域方法,计算柴油机表面的振动与噪声特性,预测机体的表面辐射声压。研究了活塞与气缸间隙对柴油机活塞敲击噪声的影响,得到机体振动与声学特性的变化情况,结果表明,通过采取减小活塞与缸套间隙的方法,可使柴油机的活塞敲击噪声得到一定的控制。展开更多
文摘Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained. A computer program for simulating the piston second order motion was conducted to calculate the lateral motion of the upper part and the bottom part of piston skirts of the engine of automotive model CA1091. From the simulated result, the maximal impacting phase and the maximal impacting region of the piston were obtained. The result can be used for designing engine, diagnosing the noise of piston knocking cylinder wall and explaining many practical fault phenomena in theory.
文摘A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process of aviation kerosene was studied using this model. The research results showed that under the working conditions of 5500 r/min and 50% throttle opening, as the ignition energy increased, the peak values of average cylinder pressure and average temperature increased, and the combustion duration shortened, The advance of the combustion center of gravity increases the tendency of the engine to knock. Under the same operating conditions, as the ignition timing advances, the peak values of average pressure and average temperature in the cylinder increase, gradually approaching the top dead center, and the tendency of engine detonation increases more significantly.
文摘活塞敲击噪声是柴油机最重要的机械噪声,控制敲击噪声一般可以从源、传递途径以及表面辐射3方面考虑,其中控制源效果最佳。基于活塞2阶运动理论建立活塞运动动力学方程,计算得到活塞与缸套间隙别为0.5 mm、1.0 mm和1.5 mm 3种工况下的活塞与缸套4个接触点位置的载荷力。建立柴油机有限元模型,基于时域方法,计算柴油机表面的振动与噪声特性,预测机体的表面辐射声压。研究了活塞与气缸间隙对柴油机活塞敲击噪声的影响,得到机体振动与声学特性的变化情况,结果表明,通过采取减小活塞与缸套间隙的方法,可使柴油机的活塞敲击噪声得到一定的控制。
