Dual Clutch Control, Function - GF27.20-P-6001KJ
TRANSMISSION 700.4 in MODEL 453.0/3/4
View of dual clutch transmission from front left
Function requirements for dual clutch control, general
- Circuit 15 ON
- Transmission not in limp-home mode
Dual clutch control, general
The dual clutch contains two combined clutches which can be used to shift one of the two sub-transmissions alternately. Sub-transmission 1 contains the odd individual gears 1, 3 and 5, while sub-transmission 2 contains the even individual gears 2, 4, 6 and the reverse gear. In driving mode, it is only possible to engage one gear of a sub-transmission at any one time (with the exception of the reverse gear) while the gear which is expected to be shifted next is preselected by the transmission control in the other sub-transmission (associated clutch still disengaged and no torque transfer). Owing to the higher drive torque to be transferred in 1st gear, its clutch is positioned on the outside of the dual clutch (larger friction surface of the clutch plates; the specific thermal load is lower).
The advantages of the dual clutch transmission are the increased vehicle dynamics, the increase in comfort resulting from jolt-free shifting, a high level of efficiency, and the virtually interruption-free transmission of tractive force.
Function sequence
The dual clutch control function can be broken down into the following function sequences:
- Function sequence for clutch control
- Clutch power-flow change, function sequence
Function sequence for clutch control
The motor drives both transmission input shafts. One clutch is on the hollow drilled transmission input shaft, the other is on the transmission input shaft running in the first transmission input shaft. The next gear can now always be pre-selected on the non-engaging transmission input shaft. One clutch opens at the shift point, while the other closes.
Clutch power-flow change, function sequence
The power flow is changed by means of a so-called overlap operation, i.e. torque transmission through one clutch is reduced proportionate to the increase at the other clutch. As torque is transferred, the drive torque from the internal combustion engine is also reduced within a defined time window by the ME-SFI [ME] control unit (N3/10).
| Overview of system components for dual clutch transmission | GF27.10-P-9994KJ |