| As the main powerhouse of the engine, crankshaft-connecting rod-piston system in the complete machine occupies an extremely important position. Its dynamic properties direct impact on the reliability and durability of the engine. There is interaction between every component as the engine works. And the components are not absolutely rigid bodies. The effect of cyclical gas pressure and moving mass inertia force will produce elastic vibration. Therefore, regarding components of crank as the elastomers and the coupling study on tribology and dynamics are necessary.First of all, simplify the three-dimensional solid model in consideration of the structural characteristics and multi-body dynamics analysis needs. Then, set up the three-dimensional solid model and the condensational FE model of crank system. AVL-EXCITE is a kind of professional software which simulates engine property. In this article, use the method that integrates the finite element method and multi-body dynamics to set up multi-body dynamic model of crank system considering film lubrication at the same time. At last, complete multi-body dynamic simulation of crank system within two working cycle and get the dynamic response in the second cycle with the given working condition. And then, analyze the main bearing lubrication. Meanwhile, build the physical environment, use the coupled method of heat-force to analyze the thermal deformation of piston and liner. Later, do some correction based on their actual size and tolerance range as to get smooth contour line of piston and liner. After that, calculate the elastic deformation of piston using the finite element method to extract the stiffness matrix. And finally, do piston secondary motion simulation using Piston&Rings program. The gap between piston and liner is an extremely important technical parameter. Its measurement direct impact on the engine property. Therefore, in the end of this article simulate the law of piston secondary motion as the gap changes. |
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