Analysis And Control Of Torsional Vibration In Diesel Powertrain Shafting Under Full Condition

With the vigorous development of the diesel multiple units, powertrain equipment have higher requirements for reliability, security and economy. At the same time, the increasing shortage of resources forced powertrain shaft to develop to the high-performance, lightweight direction. As the power transmission system, powertrain shafting torsional vibration performance plays an important role in system reliability and life, which torsional vibration problem increasingly prominent and has attracted much attention.This paper focuses on a diesel powertrain shafting, using the method of experimental research and simulation analysis on combined, studied powertrain shafting torsional vibration characteristics under full condition.For the torsional vibration problem of diesel powertrain shafting, this paper has carried on the shafting torsional vibration test analysis with spring damping type coupling and rubber elastic coupling respectively under full condition. The results show that the alternating torsional angle difference of coupling is bigger under start-up condition, and the angle amplitude of key components basically meet the requirements under steady operation condition and accelerating condition. Based on this feature, existing national standards was provided the suggestions to supplement and perfect. In addition, the shafting torsional vibration characteristics are similar when units use two kinds of couplings, and its dynamic response variation law following speed is consistent.To analyze the powertrain shafting dynamics, this paper on the elastic coupling rubber powertrain shafting, TVCA and AMESim equivalent system model is established, and the force calculation of torsional vibration was carried under full contidion. The results show that the coupling shaft torque is larger under start-up conditions, the dynamic response under accelerating condition is slightly larger than steady operation condition, while the dynamic response under stop condition is slightly smaller than start-up condition. Except the 3.0 order angle amplitude of crankshaft free end beyond the limit of 0.15°, the other dynamic responses basic meet the requirements during the diesel engine speed range.To provides reference for torsional vibration of shafting control, from the perspective of full condition, this paper comprehensively analyzed the parameters, including coupling stiffness and damping, shock absorber stiffness and motor rotor inertia, to the effect law of shaft inherent characteristics and forced dynamic response. The results show that the change of coupling stiffness and motor rotor inertia, can change the first order natural frequency, which influencs the dynamic response of the shaft system under different working conditions. And coupling damping parameter change on the shaft system had a greater influence on the resonance speed of response.To the problem of shafting torsional vibration under different working conditions, this paper have shaft torsional vibration under start-up condition been controlled from the aspects of parameter optimization, motor drives to start, and single cylinder combustion to start, and have shaft torsional vibration under accelerating condition been controlled from the aspects of parameter optimization and load characteristic optimization. Results show that this methods can effectively restrain the shafting dynamic response. In addition, from the perspective of coupling type selection design, this paper puts forward the optimization design method by using the variable stiffness coupling to achieve no main harmonic resonance within the scope of work in all stable speed.To sum up, the test results of shafting torsional vibration under full condition, provide the basis for the improvement of the test standards. Studying the effects law of key parameters on the shafting torsional vibration and analyzing the shafting torsional vibration control under start-up condition and accelerating condition, which provided the optimization schemes and ideas for the powertrain shafting torsional vibration optimization. In addition, torsional vibration performance contrast analysis with two kinds of variable stiffness elastic, which provided a reference for selection of shaft coupling.