Based on the theory of thermal elastotydrodynamic lubrication and multibody dynamics,a multibody dynamics model for crankshaft bearing of the 2D25 horizontal nonroad 2-cylinder diesel engine was established.By considering all the key influence factors,including the elastic deformation of bearing shell and bearing base,the viscoustemperature and viscouspressure characteristics of lubricating oil,the surface roughness of bearing shell and journal and thermal effect under the flexible body model,the lubrication model was established and the bearing force,oil film thickness,oil film pressure and friction power loss of each bearing under different operation condition was calculated.The results show that the total friction power loss of the main bearing and the thermal load of the bearing shell are increased with the increasing of speed.At high speed,there exists misalignment of the journal for the first main bearing(MB1)and the third main bearing(MB3),which results in eccentric wear and intensifies the vibration of the journal during the second cylinder explosion.The oil film pressure distribution of big end bearing is uniform the thermal load is low as well as the lubrication is better at the high speed.