Dual Clutch Transmissions - Lessons Learned and Future Potential

<div class="htmlview paragraph">Dual Clutch Transmissions (DCTs) are providing the full shift comfort of traditional step automatics but offer significantly improved full efficiency and performance.</div> <div class="htmlview paragraph">With up to 15% better fuel efficiency compared to planetary-ATs, the DCTs are the first automatics to provide better values than manual transmissions. Higher top speed and, more important in everyday driving, better acceleration compared to planetary-ATs and CVTs are additional benefits.</div> <div class="htmlview paragraph">DCTs are also the first automatic transmissions well suited for high torque Diesels and high revving gas engines alike.</div> <div class="htmlview paragraph">The DCT concept was originally developed in the 1940's but it took until recently that high volume production solutions were made possible and allowed for the mainstream vehicle market entry.</div> <div class="htmlview paragraph">Beside the electronic hard- and software the key enablers for the DCT are the dual wet clutch and the electrohydraulic transmission control module.</div> <div class="htmlview paragraph">On the clutch side new friction elements have been designed. Combined with an enhanced transmission fluid more than two million shifts per clutch and a consistent launch quality over the transmission lifetime are achieved.</div> <div class="htmlview paragraph">The dual clutch design itself supports very responsive clutch engagements and disengagements as well as good controllability under slipping conditions.</div> <div class="htmlview paragraph">On the controls side the electronics, sensors and electrohydraulics have been integrated into a mechatronic module for minimized tolerance bands and improved reliability.</div> <div class="htmlview paragraph">Low hysteresis, direct acting solenoids enable the precise and fast clutch control that is the key for the DCT function.</div>