DCT system approach: Choose Drive Away and shift feeling - High performance in Drive Away and shifting through control software and integrated system design

摘要

The DCT has opened up a new world of opportunities for shifting. Especially in sports car applications, the challenge is to control the clutches so that the right feeling (comfortable or sporty) is accomplished in every manoeuvre. Therefore, the clutches need to transmit the right torque at the right time. This paper presents the dual-clutch system that has the flexibility to realize the requested feeling for Drive Away and shifting. After a general overview of the developed dual-clutch system, the paper will present two special software features which contribute to the Drive Away and shift feeling. The first one is the intensive communication between the Engine Controller and Transmission Controller during Drive Away. The second one is the developed shifting software which is able to cover a whole spectrum of shift types, including an innovative sporty shift. From the presented examples, it will become clear that high performance in Drive Away and shifting requires fast and accurate clutch torque control. The paper will present the integrated system approach which has successfully overcome this challenge. This approach is based on making accurate dynamic system models which are used as an input for optimising the mechanic/hydraulic system and for developing a suitable control strategy. The approach will be illustrated with the example of clutch pressure control.