Vibration Modeling and Correlation of Driveline Boom for TFWD/AWD Crossover Vehicles

Reducing the high cost of hardware testing with analytical methods has been highly accelerated in the automotive industry. This paper discusses an analytical model to simulate the driveline boom test for the transverse engine with all wheel drive configuration on a front-wheel drive base (TFWD/AWD). Driveline boom caused by engine firing frequency that excites the bending mode of the propeller shaft becomes a noise and vibration issue for the design of TFWD/AWD driveline.

The major source of vibrations and noise under the investigation in this paper is the dominant 3^rd order engine torque pulse disturbance that excites the bending of the propeller shaft, the bending of the powertrain and possible the bending of the rear halfshaft. All other excitation sources in this powertrain for a 60° V6 engine with a pushrod type valvetrain are assessed and NVH issues are also considered in this transient dynamic model. There exist the 2^nd order unbalanced rotating couples (yaw and pitch respective to the engine coordinate system) due to the reciprocating mass of the pistons and connecting rods, and the 1½ order valvetrain unbalanced rolling moment (respective to the engine coordinate system).

A nonlinear Multi-body System Simulation (MSS) combined with a linear Finite Element Analysis (FEA) in time domain was used as a numerical tool for the evaluation of the mount vibrations at the propeller shaft center bearing at the suspected path for N&V. Finally, the TFWD/AWD boom analytical model was built using DADS* and validated with test results.