Glossary
Automotive transmissions. Contribution to noise and vibration inside vehicles

Engine torque fluctuation

Temporal variations in crankshaft displacement, speed or angular acceleration due to forces acting on piston-crank-crank systems.

Transmission damper; driveshaft damper

A mass-spring-damping system often used on transmissions to "break" a resonance due to bending of the connecting shaft or to minimize engine/wheel hub transfer.

Bourdonnement bas régime ; low RPM booming noise

Low-speed noise (< 2,000 rpm) mainly due to engine acyclism, which results in pulsating torque. Pulsating torque, amplified by the powertrain, is transmitted to the wheels. These parasitic vibrations are transmitted to the vehicle body, generating noise in the passenger compartment.

Bourdonnement haut régime ; high RPM booming noise...