Performance Evaluation & Optimization Technique for Torsional Vibration Damper System (TVDS) in Multi-Plate Clutches for Improved Drivability

In recent years with the advent of technological advancements, engine power & torque levels per unit engine displacement volume in motorcycles are showing significant increase. These powertrains however are prone to Torsional Vibration issues. The severity is even more with single cylinder engines. The Torsional Vibration Damper System (TVDS) in clutches has become critical as it plays an important role in isolating these torsional vibrations. Thereby increasing the lifespan of the critical powertrain components. The major challenge with TVDS is, it must transmit the high torques on one hand and effectively keep the high pulsations in torque away from the rest of drive train on the other. These are conflicting requirements & often result in a design compromise. Further this is revealed only at full vehicle testing. Thus it requires the full vehicle functional prototypes to be ready for first level evaluation of TVDS. This reduces the scope available for implementation of all possible design changes. Additionally during this full vehicle testing, very limited amount of information is generated regarding performance behavior such as natural frequency, isolation properties etc. This poses difficulty in optimizing TVDS methodically & restraints designers to opt for trial & error approach.

This paper describes a methodology to evaluate performance & subsequently optimize TVDS at component level during early phases of design when no prototype of powertrain is available. The aim of this study is to determine the stiffness & damping characteristics of TVDS for optimal comfort & drivability at early stages of design. The same setup can then be used to simulate the durability loads coming on TVDS on vehicle. The evaluation comprises of two modes. One is evaluation of "Free vibration response" of TVDS & other is evaluation of "Forced vibration response". The paper describes effective use of these modes to arrive at objective characterization of TVDS which has direct correlation with full vehicle based subjective evaluation. The paper also describes systemic approach for optimization of TVDS. The TVDS optimized with above evaluations is then tested on full vehicle & found to enhance the drivability significantly.