1. Field of the Invention
The present invention relates, in general, to a shift control method for a vehicle having a double clutch transmission (DCT), and more particularly, to a technology for improving a response to a speed change during a kickdown.
2. Description of Related Art
Unlike an automatic transmission (AT) which requires only clutch shifting, a DCT can enable clutch shifting only after gear shifting has been completed. Therefore, in the DCT, gear shifting performance is a key factor for an overall response to speed change. In particular, more rapid gear shifting is required for a kickdown that a driver regards most sensitive for a response to speed change.
For reference, the gear shifting refers to a speed change operation that causes a sleeve to engage with a clutch gear due to them being synchronized using a synchronizer. The clutch shifting refers to a speed change operation that transmits power that has been supplied from an engine to drive wheels by changing its speed substantially using the sleeve, the clutch gear and shift gears by engaging the working parts of a clutch of an input shaft, the gear shifting of which has been completed as described above, with each other. In addition, gear releasing refers to the process in which the sleeve is released and disengaged from the clutch gear.
In order to reduce a time required for the gear shifting, displacement optimization at a point where the synchronization by the synchronizer starts, a reduced time for the synchronizer to carry out the synchronization, displacement optimization at a point where the working parts of the clutch gear are to engage with each other, and the like are required. Among these, most time is consumed in the range of the synchronization by the synchronizer during the gear shifting. Therefore, it is necessary to reduce the time it takes the synchronizer to carry out synchronization.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.