Demands
on the clutch have become more difficult.
It is possible to drive modern engines at extremely low
rpm. A car body optimized in the wind-tunnel produces less
wind noises. New calculation methods help to reduce the weight
of the vehicle, and lean concepts increase the efficiency of
the engines. By the help of a 5th or even a 6th gear,
consumption can also be reduced. Thin oils make precise gear
shifting easier.
In a few words: There is an increase in noise sources,
whereas the natural damping diminishes. The principle of the
piston engine still exists exciting torsional vibrations in
the drive train due to its periodical combustion procedures.
Gear rattle and body boom are the unpleasant consequences.
Today's drivers used to comfort are not willing to accept such
background noises any longer.
It is more important than ever before for the clutch not
only to disengage and to engage, but also to isolate
efficiently the vibrations of the engine.
Physically this problem is easy to solve: There must be an
increase of the moment of transmission inertia without
increasing the mass to be shifted. This results in a reduction
of the rpm producing this unpleasant resonance below the idle
speed. The resonance itself, however, gets stronger.
