Research On Nonlinear Performance Of Torsional Vibration Reduction Of Circumferential Spring Dual Mass Flywheel

With the development of auto powertrain technology, the engine trend to have fewer cylinder and larger torque, which leads to increased torsional vibrarions in the drivetrain system. In addition, the raise of fuel consumption requires auto transsimion to improve mechanical efficiency. Dual mass flywheel (DMF) offers adequate potential to deal with above phenomenon. It has been proven that DMF is the most effective system in pratical for reduce torsional vibrations while lowering fuel economy in the drivertrain. Because of the blockade on new technology, DMFs on the domestic market are mostly imported from aboad, some domestic atuo manufacturers and research institutions are devoting a lot of energy to DMF research and development. Therefore, perfecting the research of DMF torsional vibration damping characteristics has great theoretical value and practical significance.Based on domestic and abroad research results and development trend about DMF, the circumferential arc spring dual mass flywheel (DMF-CS) is taken for the study object in this thesis, the nonlinear torsional vibration damping characteristics of DMF-CS is further studied, including related research as follow.Firstly, investigating structure characteristics of powertrain and taking VM engine transimission as research fundmental system, the multi-freedom torsional vibration model related to DMF-CS is established. The influence on the natural characters of torsional vibration of powertrain by moment of inertia parameters and torsional rigidity of DMF is analyzed. Verifying DMF has the effect of torsional vibration isolation, which provides thereotical references for matching DMF for powertrain system.Secondly, according to analysis of significant torsional vibration characteristics for different operating modes of vehicles, the DMF performance of reducing torsional vibration is investigated. Combined with linear torsional rigidity and viscous damping characteristics of the circumferential arc spring couple, a set of analytical formula of DMF-CS damping characteristics are derived. Furthermore, based on Bouc-Wen model, the hysteresis model of DMF is established to describe the vibration reduction characteristics, adpoting virtual simulation technology is to prove thereotical study.Thirdly, DMF with centrifugal pendulum torsion vibration absorber (DMF-CS&CPVA) system is taken as research subject. By summarizing the work principle, structural features and research methods of CPVA, the dynamic model of DMF-CS&CPVA system is established under generalized coordinates. Using comparative analysis method, the DMF-CS&CPVA performance of vibration absorption is inverstigated. Further more, the nonlinear dynamic charactisitics of DMF-CS&CPVAs integrating with different CPVA type is comparatively analyzed.Finally, using DMF-CS engine test bed and DMF-CS dynamic performance tests to verify the theoretical study. And combined with reasearh results of the DMF-CS torsion vibration isolation, torsional vibration damper, torsional vibration absorption properties, proposed a design process for DMF-CS characteristics of torsional vibration reduction, which is valuable for the research and development of DMF-CS in domestic.