Engine mount

Improved engine mount

The 1.6l TDI engine does not have a balancer shaft. The new engine mount reduces vibrations that are felt by occupants.

Tasks of an engine mount:

• Securing the engine in the engine compartment; statically (when stationary) and dynamically (on the road)
• Bearing the static engine load
• Reducing the vibrations from uneven road surfaces (shaking)
• Reducing the vibrations transferred from the engine to the body

Engine mounts are used in vehicles to prevent the transfer of vibrations from the engine to the body and to dampen the resonance vibration of the engine. Extremely hard and highly stiff mounts are required to bear the engine load and secure the engine in the engine compartment. Soft bearings are required for good acoustics in the vehicle interior. These ensure a low dynamic stiffness across a broad frequency range. In order to find a compromise for all tasks, engine mounts filled with hydraulic fluid, called hydro-mounts, are fitted.

New engine mount

The efficiency of the new engine mount has been improved by modifying the design of its hydraulic system. Careful configuration of the geometry has made it possible to use the fluid in hydraulic mounts as an “internal damper”.

Function

Large vibration amplitude

When a greater vibration amplitude acts on the mount, for example, due to an uneven road surface, the vibration energy is reduced by the damping system inside the hydro mount. This is achieved by the hydraulic fluid being pressed out of the main chamber into the compensating chamber via the damping passage. The damping reduces the shaking to a comfortable level.

Small vibration amplitude

If a small vibration amplitude acts on the mount, for example, from engine vibrations, the damping will be deactivated by the decoupling diaphragm mounted on floating bearings. In the new engine mount, the decoupling diaphragm vibrates within a certain speed/frequency range together with the hydraulic fluid against the vibrations produced by the engine. The decoupling diaphragm mounted on floating bearings prevents premature hardening of the mount. This decreases the vibrations transferred to the body. The humming/droning noises are reduced to a comfortable level so there is no need for a balancer shaft.