LuK was the first manufacturer in Europe to develop and sell a dual-mass flywheel in large-scale standard production that was able to realize this physical principle. The name says it all: The mass of the conventional flywheel was simply split in two. One part continues to belong to the engine’s mass moment of inertia, while the other part now increases the mass moment of inertia of the transmission. The two decoupled masses are linked by a spring/damping system. One clutch disc, without a torsion damper, between the secondary mass and the transmission handles the engaging and disengaging functions. A favorable side effect is that the transmission is easier to shift because of the low mass to be synchronized, and there is less synchronization wear.
A glance at the benefits of the Luk dual mass flywheel
This all makes the LuK dual mass flywheel the ideal solution.
With one drawback: the higher the mass reactance of the vibrating masses, the more excessive the resonance increase and associated torque peaks. With the dual mass flywheel, this would be easily perceived when starting and stopping the engine; much more easily than with a conventional clutch system. Additionally: the smaller flymass of the engine has less of a stabilising effect on the speed fluctuation of the engine.
Thanks to decades of experience in clutch building, the LuK specialists were able to find an excellent solution to this problem. An additional damping device effectively prevents resonance overload. In normal operation, however, this additional damping device has no function and the torsional vibrations of the engine are filtered out by spring dampers.
Friction and spring rate – the correct ratio is important.
For optimal vibration isolation and soft resonance passage when starting and stopping the engine, the ratio between friction and spring rate must be optimal. The length of the springs is a key factor: The softer a spring, the more efficiently vibrations are isolated. The extra-long springs of the latest generation of dual mass flywheels significantly reduce the spring rate compared to a first generation dual mass flywheel. In routine driving operations, excessive resonance increases are kept almost completely away from the gearbox.