| Compression ratio is one of the important technical parameters of the engine,which directly determines the engine’s thermal efficiency and emissions,and has an important impact on engine power and torque output.The variable compression ratio engine not only has good fuel adaptability,improves the engine thermal efficiency,greatly improves the engine’s economy,but also can effectively improve the emission of pollution emissions.This paper designs a new type of variable compression ratio connecting rod structure,the structure can be realized according to different working conditions of the engine,the control mechanism of supporting point to change the location of the piston stroke to the compression ratio of the continuous change of the function.Under the condition of satisfying the structure function and stable work,the size and quality of the related structure are close to the traditional engine.In order to verify the rationality of the engine design and ensure the smooth,safe and reliable operation of the engine,the 3D model of the new type of variable compression ratio connecting rod structure was established by modeling software Solid Works,and the model was imported into dynamic simulation software ADAMS.The modal neutral files of connecting rod and connecting rod cover were generated by ANSYS software,the rigid-flexible coupling model of the new type of variable compression ratio connecting rod structure was established by replacing the original rigid part with flexible body,the kinematic relationship of the model was verified.The dynamic characteristics of the link mechanism under different operating conditions were simulated,and the contact force between the structural members was obtained.The dynamic stress distribution and deformation cloud of the connecting rod and the connecting rod cover were also obtained.The modal frequency and vibration deformation of link mechanism were obtained by vibration simulation of rigid-flexible coupling model.The mode shapes of the connecting rod and connecting rod cap under free and restrained conditions are obtained by the ANSYS software.The harmonic response of the connecting rod was analyzed based on the modal analysis.The application of multi-body dynamics simulation technology to the dynamic characteristics of engine link structure can not only discover some problems existing in the initial structure of the engine,but also optimize the parameters of the relevant structure according to the simulation results,Performance analysis and evaluation of new products,can effectively reduce the engine R&D costs.In addition,the research methods to solve other similar engineering problems also have some reference value. |
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