The crankshaft twist is of great concern for heavy duty engines. In order to have a longer B10 life and better NVH characteristics, it is desired to have minimum Torsional vibrations (TV) in the crank shaft. To keep the crankshaft twist in check - TV dampers are used. Aneasier approach is to use a Viscous TV damper which keeps TV below acceptable limit for entire speed range. But this is a very costly approach.
In this paper, the design of rubber TV damper for multi-cylinder engine was optimized to have lower TV characteristics. The optimized rubber damper has been developed with AEM - VAMAC™ grade rubber. This material provides advantages of better TV attenuation, higher thermal resistance, oil resistance higher durability and a much longer life than other rubber compositions. Besides rubber profile was also optimized to obtain higher slip torque.
The TV amplitudes with existing rubber compound (EPDM -Ethylene Propylene Diene Monomer) were measured in the engine testbed. The optimized TV damper with AEM - VAMAC™ rubber compound clearly indicates a reduction of about 50% in TV amplitudes for the critical orders of a multi-cylinder diesel engine.
Post validation, the optimized rubber damper was introduced in production and has helped in reducing field complaints significantly. Higher service life and lower warranty cost are the advantages seen with this optimized rubber damper.