Abstract
KEYWORDS
Wet and dry Twin Clutch, Low-pressure Pump, Modular Concept, Hydraulic Actuation, Judder Control
ABSTRACT
The clutch with its actuating mechanism is of particular importance for modern twin clutch transmissions. Their target is to achieve the best solution with regard to efficiency, robustness, comfort and isolation of vibration. Because some of these requirements are contradictory, it is essential to find a suitable solution. A comparison of twin clutch systems with wet and dry clutches demonstrates the individual weaknesses of both systems. On dry clutches, it is the limitation of thermal load capacity. For wet clutches, it is the reduced efficiency, caused mainly by the oil pump, together with the higher costs. A wet clutch controlled by an electromotive actuator, which uses a suction controlled low-pressure circulation pump for cooling, largely avoids hydraulic losses and guarantees the clutch cooling function. Using hydraulic clutch operation as an example, this article demonstrates how the hysteresis of the clutch and actuating mechanism can be reduced to a minimum. Wet and dry clutches occasionally have a tendency to judder. It will therefore be demonstrated how judder can be suppressed effectively by an anti-judder control, thereby increasing the comfort of launch clutches. On wet clutches, this may even result in prolonged oil change intervals.