SEA for diesel engine transfer path: application of SEA for diesel engine noise reduction through transfer path analysis

摘要

The main objective of the paper was to evolve a methodology for mmimising vibration transmission through a reciprocating mechanism, which is the dominant path of vibration transmission in a diesel engine. Vibration transmission in this path in a diesel engine is in the range of 800 to 3000 Hz. Since statistical energy analysis is applicable in this frequency range, it was used for the transfer path analysis, from the viewpoint of minimising vibration transmission. The transfer path, consisting of piston, piston pin, connecting rod and crank pin was constructed using simple elements like beam, plate and shell, which enabled the use of analytical results for modal density. Damping loss factors and coupling loss factors were measured experimentally. Modal density of all the subsystems was computed analytically and then compared with the experimental measurements. Coupling loss factor was analytically determined for a beam-beam connection, which enabled fine tuning of the experimental method of determining coupling loss factor between the subsystems of the transfer path model. After evaluating all the SEA parameters, the energy ratio between the piston and crank pin was computed. A total of eight different transfer path models were constructed with some variation in their dimensions and materials used for construction. Based on these results, certain recommendations were made for designing such paths for minimum vibration transmission.