| During the operation of the engine,the transmission system which is affected by the periodic torque will inevitably produce torsional vibration.Torsional vibration of the transmission system not only causes knock of transmission gear,but also affects the key system function of engine,such as the timing system,fuel injection system and so on,and it is also one of the most prominent problems of customers’ feedback in the market.As an important part of power train system,the selection of dynamic characteristics of dual mass flywheel will directly affect the torsional vibration of the power train system.The traditional method only considered the influence of the dual mass flywheel in the end of the transmission,without considering the influence of the response of torsional vibration in the end of the engine.In this study,when studying the influence of the dynamic characteristics of double mass flywheel on the torsional vibration response of powertrain,I not only consider the influence of double mass flywheel on the transmission side,but also the torsional response of the engine.The main research work shows as follows:Based on the lumped parameter method,the torsional vibration analysis model of powertrain with dual mass flywheel and clutch torsional vibration damper is created,which consists of three cylinder engine,clutch,dual mass flywheel,a six-speed manual transmission with front-wheel drive,transmission shaft,and dynamometer.The torsional vibration characteristics of the two models under steady-state 1000r/min,2500 r/min and raising speed from 1000r/min to 3000r/min is calculated by using the measured cylinder pressure as excitation source.The simulation results show that the dual mass flywheel is lower than the idle speed of the torsional vibration frequency of the powertrain;The dual mass flywheel can reduce the inhomogeneity of input speed of the transmission,but increase the speed fluctuation of the end of primary flywheel,and the 1.5 order angular acceleration of the end of damping pulley Hub and the end of primary flywheel.The test about torsional vibration of powertrain is carried out by means of non-contact measurement method,and then I compare the calculation results of torsional vibration analysis model of powertrain driveline with it.The results show that the 1.5 order angular acceleration before and after vibration reduction of the dual mass flywheel,and the 1.5 order torsional angle of the end of damping pulley Hub and the flywheel,are slightly different between the amplitude and the peak value of the corresponding rotation speed,mainly due to the assumption and simplification of the torsional vibration analysis model and the uncertainty of the structural damping of some components in the simulation model.Finally,based on the results,the reliability of the torsional vibration model of powertrain is verified.Based on the torsional vibration analysis model of powertrain with dual mass flywheel,the effects of three basic parameters of the double mass flywheel on the torsional response of the engine,the inherent characteristics of powertrain and the fluctuation of the input speed of the transmission are studied by changing these parameter.Considering the above factors,determine the range of three basic parameters of the dual mass flywheel: the moment of inertia between 0.9 and 1.1,torsional stiffness between 3.36Nm/deg and 4.25Nm/deg,hysteresis torque between 5Nm and 7Nm. |
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