Dual Degree of Freedom Vibration Damper (DDVD) for Driveline Noise and Vibration Issue Resolution 2015-01-2177

Powertrain and driveline systems interaction in rear wheel drive vehicle development has recently gained attention for the improvement of interior noise and vibration in emerging markets. The driveline is a significant path for engine-generated noise and vibration to reach the interior occupant interfaces, where it affects refinement perception. The interaction of powertrain excitation orders and driveline resonant responders covers a wide range of frequency and vehicle operating conditions. This interaction poses significant challenges during vehicle development. With recent increased demand for higher specific power from diesel engines, driveline refinement has become even more challenging, especially for rear wheel drive vehicles.

Two driveline related refinement issues were observed during evaluation of a RWD vehicle. Root cause analysis determined that the first issue (lower rpm boom noise and vibration) was due to engine torsional excitation of the driveline. The second issue (higher overall noise at higher rpm) was due to a propeller shaft bending resonance. Separate solutions using known technology were available for the two issues; a Torsional Vibration Damper (TVD) for the torsional boom and an Internal Tuned Damper (ITD) for propeller shaft bending resonance. The challenge was to find a new single solution which could mitigate both issues without affecting current driveline architecture. A Dual DoF Vibration Damper (DDVD) was developed to solve the above mentioned driveline noise and vibration issues.

The DDVD is designed and tuned to work as torsional vibration damper in the rotational direction and as linear vibration damper in the radial direction. The paper describes the design and tuning of the DDVD to reduce the two critical driveline induced noise and vibration issues. The problem description, root cause steps, and alternate solutions prior to DDVD development are also discussed.