Simulations and testing approach for 4WD Powertrain vibration reduction

摘要

Powertrain dynamic analysis is a complex problem to resolve in 4WD application. This is mainly due to lower Powertrain stiffness with Transfer case as a heavy element added at the extreme end in case of Inline engines. This leads to frequent excitation of Powertrain at its natural frequencies during real world usage. Sustained operation at these conditions leads to structural failures because of large vibration amplitudes at resonance. This paper highlights the process followed to design a tuned absorber to restrict the failures. Both simulation & physical testing was conducted to understand the root cause of the problem. Since time required acquiring data on the vehicle running on high speed test tracks was too long, the condition simulated on the stationary vehicle ensuring very good correlation of Powertrain behavior between two conditions. The reduction in testing time with this approach was appreciably high. As an countermeasures within given conditions, tuned dynamic absorber was designed to reduce the problem vibration which in turn successfully blocked the structural failures & oil leakages. The solution was validated in two stages, first on powertrain test rig & secondly on the actual vehicle under real world usage profile.