LuK GmbH & Co. KG · Germany

In principle, the converter hydraulically transfers engine torque onto the transmission intake shaft. The pump and therefore the entire converter housing has a torque-proof connection to engine and turbine via hub overlap with the transmission intake shaft. The entire converter is filled with gear oil. The pump and turbine accommodates blades, which at differential speed cause a circular oil flow between pump and turbine. The oil is extracted from the internal diameter of the pump and forced outwards by the centrifugal force. The oil is then cast from the pump into the turbine, where it is deflected by the turbine blades. This generates a torque in the turbine and/or the transmission intake shaft.

At start-up or high differential speeds between pump and turbine, the oil flow is deflected into the turbine and forces the guidewheel backwards. However, installed inside the guidewheel is a freewheel that causes the guidewheel to be disabled by the stator shaft when reversing. This generates a guidewheel torque, which increases over engine torque by up to factor 3 due to the torque equilibrium in the converter. Converter efficiency is therefore particularly high in start-up situations.

It must be considered that the hydrodynamics of the converter can only transfer torque when there is a speed differential between pump and turbine. When, during driving, the speed between pump and turbine has equalised, a bridge clutch hydraulically activated by the gearbox engages. This eliminates slip and power loss during converter operation, thereby reducing fuel consumption. LuK guarantees early bridging and thus economic consumption through the use of innovative dampers.

On the engine side, the converter is mounted to a flexible flywheel. The pump collar usually also acts as a drive for the oil supply pump on the automatic transmission. To achieve optimal performance, LuK consistently employs Computational Fluid Dynamics (CFD) simulation tools for optimal flow control and thus reduced consumption in the vehicle.