Based On The Diesel Engine Body Structure Strength Of The Multi-body Dynamics Analysis

With the increasing requirements to the speed and light of cars, the mechanical load of engine block, one of the main bearing components of engine, increase greatly, which will weaken the stiffness and the strength.of the engine block. The power, economy and reliability of the diesel are iMPacted greatly by the dynamic characteristic and strength of the engine block. Therefore, the stiffness and strength of the engine block should be calculated and analyzed during the design of the diesel engine block in order to make the program of the improve and optimization more reasonably.In this paper, the structural strength of the engine block is calculated and analyzed based on multi-body dynamics of the diesel, aiming the new type of horizontal twin diesel.Firstly, the engine multi-body dynamic simulation model was established, and the iMPact of the flexible model to the main forces of the engine block was studied by coMParing the result of the flexible model and rigid model dynamics simulation. The main forces of the engine block were obtained at the same time.The displacement, tress and train cloud were obtained through the calculation of the structural strength of the engine block in the preload conditions, the outbreak of the first cylinder and the outbreak of the second cylinder. The danger regions of the engine block strength were found, and the fatigue strength of dangerous regions were calculated. The weak parts of the engine block were found by calculating the safety fatigue factor.The dynamics characteristic and surface vibration test of the diesel engine block were studied. The result showed that the stiffness of diesel engine cylinder part were good while the stiffness of the block skirt, the main bearings and diaphragm were worse; The parts that the vibration were serious included the cylinder head, upper block, the junction between the upper block and the block skirt.Based on the calculation and analysis above, the improvement of the engine block structure was carried out. The best improvement program was obtained by coMParing different improve programs. The strength of the improved diesel engine model was calculated, and the result of the calculation showed that the displacement, stain of the engine block were better than the origin engine block, and the stress was significant smaller than the pre-improve one, so it achieved the desired effect.