Dual clutch control system |
1 | Clutch actuation cylinder |
2 | Dual clutch pressure sensor |
3 | Throttle |
4 | Oil sump |
5 | Dual clutch actuator (actuator motor) |
6 | Pump |
7 | Oil filter |
P25.30-0001-72
Overview
This document contains information on:
General
Function requirements
Function
General
The clutch control is operated by a pump that is driven by an electric motor (dual clutch actuator).
Function requirements
Engine management ON (circuit 87M)
Function
Dual clutch control
The dual clutch actuator (5) drives the pump (6) and draws the transmission oil out of the oil sump (4) of the dual-clutch transmission. For fine-filtration purposes the drawn-in transmission oil flows through the oil filter (7) beforehand. As the oil is delivered to the clutch actuation cylinder (1), the dual clutch pressure sensor (2) permanently determines the delivery pressure.
Once the clutch actuation cylinder (1) is filled with transmission oil, the supplied transmission oil then flows through the throttle (3) back into the oil sump (4). Depending on the transmission oil delivery rate involved, the throttle (3) generates a drop in pressure. The generated drop in pressure is equivalent to the pressure in the clutch control system.
Depending on the equivalent drop in pressure for the transmission oil delivery rate, a direct correlation can then be made between the pump speed and the pressure.
The dual clutch pressure sensor (2) permanently records the pressure in the dual clutch control system and sends this to the dual-clutch transmission control unit.
Dual clutch control during gear change
For dual clutch control when changing gear the gear to be engaged has to have been preselected. Each sub-transmission has a clutch and a pump (6) assigned to it for the dual clutch actuator.
The overlap from clutch K1 to clutch K2 is reached when the engine speed of the disconnecting clutch is reduced while, at the same time, the engine speed of the closing clutch increases.
The pump (6) is continuously in operation when the clutch is closed.