POSSIBILITIES OF USING DYNAMIC TORSIONAL VIBRATION DAMPERS WITH SPRINGS IN IC ENGINES FOR ROAD VEHICLES

One of the main reasons of fatigue of the IC engine crankshaft, which inevitably leads to its failure, is the occurrence of high amplitudes of twist angle due to torsional vibrations. Amplitudes of twist angle due to torsional vibrations are particularly pronounced in vibration resonant modes of the crankshaft including crank-gear and other associated elements. An objective way to reduce the torsional vibration amplitudes of twist angle is the application of the torsional vibration dampers (TVD). So far elastic TVD with rubber as elastic element are used for high and medium speed engines for road vehicles. The main reasons are simple construction, reliability and relatively low costs of this type of additional elements. Modern production technologies of crankshaft system elements allow implementation of dynamic TVD with springs for highspeed as well for medium-speed engines for road vehicles (e.g. dual-mass flywheel, a damper in the counterweight etc.).This way, reliability is increased and the costs for TVD are reduced. A method for selecting characteristics of the dynamic TVD with springs built in the counterweight (torsional rigidity, inertia inertial mass), as well as an analysis of its impact on the critical values of the angular amplitudes of twist angle due to torsional vibrations are presented in this paper. The results of analysis are compared with the corresponding angular amplitudes of twist angle of the crankshaft with an elastic TVD element, and the potential of amplitudes of twist angle reduction by selection realistic dynamic characteristics of the dynamic TVD are shown. The complete analysis is carried out for a specific medium speed truck diesel engine