Effect of Torsional Vibration on Transmission and Validation Process 2024-26-0363

Transmission of a vehicle, being driven by an internal combustion engine is susceptible to torsional vibrations which are inherent property of an internal combustion engine. Torsional are produced in the engine because of multiple power strokes happening in multiple cylinders of the engine at regular intervals. These torsional vibrations affect each and every rotating component in the powertrain. A lot of work has been done in past in the area of ECU calibration, flywheel inertia, clutch dampener springs etc. to reduce the vibrations. These methods have limitations for the extent of damping that can be introduced into the system. Un-damped torsional vibrations when transferred further it affect rotating / oscillating components of transmission. Inside the transmission, it leads to rattle issues and affect the life of synchronizers or engaging gears. This paper describes the methodology to address the effect of high torsional vibration on synchronizer of commercial vehicle. This paper also gives details of the procedure to derive the torsional vibration duty cycle to validate the transmission. This paper deals with tests carried out on different combinations of synchronizer and engaging gear designs against varying torsional vibration levels to arrive at optimum design for the given torsional vibrations. Based on the sensitivity study and the validation results this paper also provides the design guideline for optimize design of transmission components against torsional vibration.