Analytical Investigation On Strength And Main Bearing Lubrication Of CA4D32 Diesel Engine Crankshaft System Based On A Simulation Technique

Crankshaft bearing system is one of the most important components in Internal Combustion Engines (ICE). The analysis on dynamics, tribology, stiffness and strength for the crankshaft bearing system has to be done when engineers design a 1C engine. It directly affects reliability and durability of the engine. The multidisciplinary performance such as dynamics tribology stiffness and strength have been researched independently in the extent of respective discipline for a long period of time because crankshaft has a complex geometric structure and the crankshaft bearing system is applied by a complicated variable load. The multidisciplinary performances of the system happen simultaneously and affect each other as engine works. The coupling study on dynamics tribology stiffness and strength is very important both in theoretical and practice sense. The Multi-body system Dynamics and the finite element analysis make the precise analysis of crankshaft being true.A method that combined finite element method with multi-body dynamics simulation is applied to carry on dynamics analysis simulation on the CA4D32 diesel engine crankshaft system in this article. Its main research content is: Establishes reasonable diesel engine crankshaft system dynamics model, completes the simulation in an action cycle, and obtains the power response characteristic which displays in one operation cycle. Then it carries on the transient dynamics analysis on crankshaft using finite element analysis software.First, in view of the concrete product unique features as well as the following functional analysis characteristic simplify the crankshaft system. The two kinds of CA4D32 diesel engine shafting models according to different simplified degrees are created. shafting condensed models used for the following multi-body dynamics model are established, and the multi-body dynamics model is also created. Then, the result of shafting model analysis is contracted with factory experiment data. It proves the shafting models are reasonable. According to the results of EXCITE multi-body dynamics simulation, The multi-body dynamics analysis of the diesel engine shafting, which consists of crank force, torsional displacement of the shafting free end, shafting displacement, speed motion and so on, is implemented. Obtaining the power response characteristic which displays in one operation cycle proves the multi-body dynamics model reasonable further. Simultaneously carries on the bearing load analysis, and obtains the minimum oil film thickness, the peak oil film pressure, orbital path of main bearings and so on. The lubrication condition of main bearings is analyzed. We can know lubrication condition of the third main bearing is bad, which needs optimization. Last, it carries on the transient analysis of the crankshaft, and comparison with the traditional finite element method. The results indicate that, the maximum stress of the crankshaft is within its allowable scope, the rigidity of crankshaft is enough and the distortion is slight. The maximum stress of different time interval is all occurred on the joints of main journal and connecting rod journal. Therefore, the joints are important points in the structural design and optimization. Using multi-body dynamics and 3D finite element method, has provided the powerful technical guarantee for precise dynamics simulation of crankshaft, and the innovation design, the modification design and the optimized design.