عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Study about reasons of engine vibration can help to improve the engine performance and comfort of the passenger. In this paper, the effect of oil viscosity on the engine vibration is investigated in the experimental and analytical simulation methods. For this purpose, firstly, by performing experimental tests, the engine vibrations were obtained in the vertical direction at different engine speeds and different oil temperatures which change the oil viscosities. Then, according to the experimental tests conditions in the laboratory, a suitable model for engine vibration in the vertical direction has been presented. In numerical simulation, the external forces that affect the system along the vertical direction are the force due to acceleration of piston, connecting rod mass center, and the oil-resistant force against the motion of the piston. The governing equations are derived and then the system vibration response is obtained in a steady state by using Fourier series method. To ensure the accuracy of mathematical modeling, the simulation results are confirmed by experimental results. At the end, the engine vibration in the vertical direction is studied at various temperatures and various engine speeds. The results show that by increasing engine speed and also increasing the oil temperature (reducing oil viscosity), acceleration R.M.S of engine increases in the vertical direction.