| Dual mass flywheel(DMF)is a new structure based on the improvement of the traditional single mass flywheel.Compared with the traditional clutch(CTD)system,the torsional vibration damper has low stiffness,large damping and a large angle of rotation.The characteristics can effectively improve NVH problems such as start-up jitter and car-cracking under starting conditions,but reasonable parameter matching is the key to its good performance.In this paper,two typical vehicle operating conditions: vehicle idling condition and driving condition are used as the modeling environment to analyze the influence of the dual mass flywheel related structural parameters on the NVH performance of the vehicle.The main work of the article is as follows:(1)Explain the research significance of this topic and analyze the research status of related issues at home and abroad.The structure and classification of the dual mass flywheel are introduced,and the working principle of the dual mass flywheel is analyzed.(2)The transmission torsional vibration model of vehicle driving conditions and idling conditions is established.Using Matlab programming,a set of general-purpose traditional system inherent characteristic calculation software is formed.The calculation results show that the second-order natural frequency decreases from 31.50 Hz to 10.93 Hz under idle conditions,and the third-order natural frequency decreases from 27.78 Hz to 12.21 Hz under driving conditions,indicating that the dual-mass flywheel can reduce the low-order natural frequency of the drive train.Based on the sensitivity analysis,the design methods of dual mass flywheel inertia ratio and torsional stiffness are proposed,and an example is illustrated with a certain vehicle.(3)The torque transmission model of the dual-mass flywheel is established and verified by the dual-mass flywheel torsion test rig.The dynamic response calculation model and optimization model of vehicle idling conditions and 4-speed WOT(Wide Open Throttle)driving conditions were established.The effects of the parameters of the dual mass flywheel on the vibration damping performance of the dual mass flywheel are studied.The optimization results show that the weighted decay rate has increased from 77% to 86% under the four-speed WOT driving condition,and the decay rate has increased from 13% to 60%under the idling condition.(4)Interval uncertainty analysis is performed on each structural parameter of the dual-mass flywheel.Based on the Chebyshev polynomial,the interval model is established.Based on the calculation results of the dynamic response under the condition of deterministic parameters,the dynamic response of the vehicle at idle speed and driving conditions is established.The proxy model and the parameter optimization model were analyzed,and the error analysis of the proxy model was conducted.The errors were all less than 3%,which verified the accuracy of the optimization results.(5)According to the optimization results,an example of a dual-mass flywheel is illustrated.The vehicle matching test of the dual-mass flywheel is designed,and the optimization conclusion is verified by combining the vehicle test results.The research in this article can provide effective guidance for the design of dual-mass flywheels,simulation of drive trains,and vehicle matching tests,and is of great significance for the promotion and application of dual-mass flywheel products. |
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