## 1 Introduction
By loading the calculation model with test data, the vertical acceleration response of the diesel engine foot is calculated and compared with the test data. The calculation and the experimental results are in good agreement with the trend [19]. There is a complicated contact relationship between the main journal and the main bearing of the diesel engine, and researchers mostly used the spring damping model to simulate it. In recent years, researchers tried to combine the multi-body dynamics with tribology in the diesel engine dynamics. [PERSON] et al. calculated the influence of different oil film stiffnesses and bearing clearances on the calculation results of the shock response. From the calculation results, it can be concluded that the oil film stiffness has a greater impact on the shock response. With the increase in the oil film stiffness, the stress response of the structure tends to increase. The bearing clearance also has a greater influence on the shock response of the mechanism. As the bearing clearance increases, the stress response of the structure increases first and then decreases [8]. [PERSON] et al. calculated the lubrication of diesel engine bearings in external impacts for a V-type six-cylinder diesel engine and used the difference method to solve the oil film pressure distribution of the sliding bearing, the maximum oil film pressure, and the maximum stress of alloy bearing. From the calculation results, the bearings are safe under impact [17]. The research of [PERSON] et al. [20] and [PERSON] et al. [21] pointed out that the crankshaft bending has a significant impact on the local axis trajectory, the maximum oil film pressure, the minimum oil film thickness, the distribution of the oil film pressure, and other lubrication results. The research of elastohydrodynamic lubrication theory is developing rapidly [22; 23; 24; 25; 26; 27; 28; 29; 30; 31] and is widely used in the bearings of diesel engine [32; 33; 34]. [PERSON] et al. increasedthe minimum oil film thickness of the main bearings by increasing the width of the oil groove and reducing the oil supply pressure [35]. Through research, [PERSON] et al. found that the deformation of the main bearing hole directly affects the state of the oil film, and the improvement of the structure can reduce the wear on the contact surface [36]. [PERSON] et al. studied the influence of surface roughness and texture direction on the bearing lubrication performance [37]. [PERSON] et al. analyzed the influence of bearing clearance, bearing width, oil supply pressure, and lubricating oil quality on the lubrication performance [38]. [PERSON] et al. significantly reduced the asperity contact pressure and the wear on the bearing edge using the variable wall thickness design of the bearing bush [39]. [PERSON] et al. optimized the lubrication characteristics of the main bearing using an orthogonal experiment and neural network methods [40]. [PERSON] et al. analyzed the influence of different surface topography and journal tilt on the distribution of oil film pressure and oil film thickness [41]. [PERSON] et al. studied the influence of the crankshaft balance rate on the main bearing's minimum oil film thickness, maximum oil film pressure, shaft trajectory and lubricating oil filling rate [42]. [PERSON] et al. conducted an analysis on the elastohydrodynamic lubrication performance of the main bearing of a low-speed marine diesel engine [43; 44]. [PERSON] studied the influence of journal deflection and tilt on oil film lubrication and wear [45]. [PERSON] et al. [46] and [PERSON] et al. [47] studied the thermal elastohydrodynamic lubrication of thrust bearings. [PERSON] et al. [48] used a mixed thermal elastohydrodynamic model to study the hybrid lubrication phenomenon of sliding bearings under heavy load conditions.