Biaxial Balancing Scheme Design And Performance Study Of 8V280 Diesel Engine

Biaxial balance mechanism design and balance performance of 8V280 diesel engine is a project which was carried out by CRRC QISHUYAN CO.LTD and our school.Compared to inline 8-cylinder diesel engine,V8 diesel engine axial size is short,light weight,very conducive to the installation of the locomotive layout;But there is a large imbalance force and torque in V8 diesel engine,if the balance problem can’t be resolved well,will make the diesel engine related equipment damage,So the balance device of 8V280 diesel engine should be designed,and evaluate the performance of the diesel engine.The main research work is as follows:(1)On the two types of crank,four cylinder angle under the balance of diesel engine performance calculation,compare and select the most suitable for 8V280 diesel engine crank type and cylinder angle.On this basis,the overturning moment of diesel engine is calculated,and the curve fitting and harmonic extraction are carried out by MATLAB software.(2)The 3D model of 8V280 diesel engine was built and assembly by the Pro/E software.After the assembly is completed,it is introduced into the multi-body dynamics simulation software ADAMS.The material of the model is introduced and the constraints and driving are added to establish the multi-rigid body model of 8V280 diesel engine.(3)Based on the theoretical design and simulation analysis,according to the balance characteristics of the diesel engine,an appropriate balance shaft space layout is designed.On this basis,the phase of the balance shaft is designed and verified by simulation analysis.Then,the mass distribution and structural parameters of the balance shaft are designed,the structure parameters include the cross section shape and width.Finally,the model is established to test whether the natural frequency will cause the resonance of the diesel engine.(4)According to the dimensions and parameters of the balance shaft,the balance shaft model is established and assembled to the multi rigid body model.The dynamic simulation analysis of the diesel engine before and after the installation of the balance shaft is carried out,and the overturning moment curve is measured and compared with the theoretical calculation results;The model of the 8V280 diesel engine rigid and flexible coupling was established,and the vibration intensity of the diesel engine was measured to verify whether the vibration condition was in accordance with the standard.Through the above research work,we can draw the following conclusions:(1)Through the balance of diesel engine performance calculation,the plane crank,cylinder angle of 60 ° arrangement is more suitable for 8V280 diesel engine.The overturning moment of the diesel engine is calculated and the curve of the overturning moment is fitted and harmonic extracted by MATLAB software,which lay a solid foundation for the design of the later biaxial equilibrium scheme.(2)The overturning moment curve simulated by the 8V280 diesel engine model is consistent with the theoretical calculation,which fully validates the accuracy of the model(3)Through the theoretical design and simulation analysis,V-axis mirror symmetrical layout is more suitable for biaxial equilibrium scheme,while offsetting the second-order reciprocating inertia force,the partial overturning moment is attenuated;The phase of the balance shaft is designed to be 11.734 degrees,and the amplitude of the overturning moment fluctuation is obviously reduced by the dynamic simulation analysis;The fan shaft is more in line with the low quality requirements of the balance shaft,the angle of the fan is designed to be 180 degrees,the radius of the sector is designed to be 38 mm,and the thickness of the balance shaft is 400mm;Through the modal analysis of the balance shaft,the natural frequency of the balance shaft is different from the natural frequency of the diesel engine,which will not cause resonance.(4)Through the dynamic simulation analysis,the overturning moment curve of the diesel engine before and after the balance is very consistent with the theoretical calculation results.The fluctuation amplitude of the overturning moment is reduced by 85.24%.After confirming the accuracy of the model,it also confirms the double-axis equilibrium scheme effect;After installing the balance shaft,the vibration velocity of the diesel engine is 10.28 mm / s,which reaches the "allowable" level,and the validity of the balance scheme is verified again.