Torsional Vibration of Turbocharged Diesel Engine on the Occasion of Low Temperature 871220
Turbocharged diesel engines prevail not only in the European and American markets, but in the Japanese market. But many problems due to higher brake mean pressure have not been cleared especially in the field of reliability and durability. Torsional vibration is one of remained problems and particularly, on the occasion of low temperature, dynamic behavior of crankshaft and torsional damper has been unknown heretofore. Furthermore, combustion pressure which is exciting force for torsional vibration has not been grasped in detail. Therefore, this paper deals with experimental studies which were conducted in a special cold test ceil using a turbocharged diesel engine for automotive use installed with rubber damper. It has been found that torsional vibration of crankshaft gets bigger at low temperature than at normal temperature. On the contrary, distortion of damper rubber shows nearly zero. This is because stiffness of damper rubber becomes higher due to low temperature. And simulating works have also indicated that stiffness of damper rubber at low temperature is forty times as stiff as that of normal temperature.