Methodology Development for Torsional Vibration Measurement and Processing in Powertrains

Torsional vibration is a characteristic phenomenon of automotive powertrains. It can have an adverse impact on powertrain related noise as well as the durability of transmission and drivetrain components. Hence minimizing torsional vibration levels associated with powertrains has become important. In this context, accurate measurement and representation of angular acceleration is of paramount importance. A methodology was developed for in-house vehicle level torsional vibration measurement, analysis and representation of results. The evaluation of torsional vibration has two major aspects. First, the acquisition of raw rotational data and secondly, the processing of acquired data to arrive at usable information from which inferences and interpretations can be made about the behavior of the rotating element. This paper describes the development process followed for establishing a torsional vibration evaluation methodology. Various factors that affect the acquisition of angular acceleration data like the type of sensor, pulses per revolution, sampling rate etc. are covered in detail. The paper also elaborates on the processing of captured data. Processing parameters including - filtering, amplitude reporting, signal processing (time v/s angle/order domain) and their impact on the final results is discussed.