In this study, a dynamic model of a single-cylinder four-stroke diesel engine has been created, and the crankshaft speed fluctuations have been simulated and validated. The dynamic model of the engine consists of the motion equations of the piston, conrod, and crankshaft. Conrod motion was modeled by two translational and one angular motion equations, by considering the kinetic energy resulted from the mass moment of inertia and conrod mass. Motion equations involve in-cylinder gas pressure forces, hydrodynamic and dry friction, mass inertia moments of moving parts, starter moment, and external load moment. The In-cylinder pressure profile used in the model was obtained experimentally to increase the accuracy of the model. Pressure profiles were expressed mathematically using the Fourier series. The motion equations were solved by using the Taylor series method. The solution of the mathematical model was performed by coding in the MATLAB interface. Cyclic speed fluctuations obtained from the model were compared with experimental results and found compitable. A validated model was used to analyze the effects of in-cylinder pressure, mass moment of inertia of crankshaft and connecting rod, friction, and piston mass. In experiments for 1500, 1800, 2400, and 2700 rpm engine speeds, crankshaft speed fluctuations were observed as 12.84%, 8.04%, 5.02%, and 4.44%, respectively. In simulations performed for the same speeds, crankshaft speed fluctuations were calculated as 10.45%, 7.56%, 4.49%, and 3.65%. Besides, it was observed that the speed fluctuations decreased as the average crankshaft speed value increased. In the simulation for 157.07, 188.49, 219.91, 251.32, and 282.74 rad/s crankshaft speeds, crankshaft speed fluctuations occurred at rates of 10.45%, 7.56%, 5.84%, 4.49%, and 3.65%, respectively. The effective engine power was achieved as 5.25 kW at an average crankshaft angular speed of 219.91 rad/s. The power of friction loss in the engine was determined as 0.68 kW.

本研究建立了单缸四冲程柴油机的动力学模型，并对曲轴转速波动进行了仿真验证。发动机的动力学模型由活塞、连杆和曲轴的运动方程组成。通过考虑质量惯性矩和连杆质量产生的动能，连杆运动由两个平移方程和一个角运动方程建模。运动方程涉及缸内气体压力、流体动力和干摩擦、运动部件的质量惯性矩、启动力矩和外部负载力矩。模型中使用的缸内压力曲线是通过实验获得的，以提高模型的准确性。压力分布使用傅立叶级数以数学方式表示。使用泰勒级数方法求解运动方程。数学模型的求解在MATLAB界面中通过编码进行。从模型获得的循环速度波动与实验结果进行了比较，发现是可兼容的。使用经过验证的模型来分析缸内压力、曲轴和连杆的质量惯性矩、摩擦和活塞质量的影响。在 1500、1800、2400 和 2700 rpm 发动机转速的实验中，观察到的曲轴转速波动分别为 12.84%、8.04%、5.02% 和 4.44%。在对相同速度执行的模拟中，曲轴速度波动计算为 10.45%、7.56%、4.49% 和 3.65%。此外，观察到随着平均曲轴速度值增加，速度波动减小。在 157.07 的模拟中，188.49、219.91、251.32和282.74 rad/s曲轴速度，曲轴速度波动率分别为10.45%、7.56%、5.84%、4.49%和3.65%。在 219.91 弧度/秒的平均曲轴角速度下，发动机的有效功率达到 5.25 千瓦。发动机中的摩擦损失功率被确定为 0.68 kW。