Electric Oil Pump
The electric oil pump
is located centrally on the TCM and is connected to the TCM via an electrical connection.
The main task of the electric oil pump is to support the primary pump in the following operating conditions:
- At low rpms
- During start/stop operation
- At high transaxle fluid temperatures (support for clutch cooling)
The TCM actuates the electric oil pump at low combustion engine speeds (coast down shifting and upshifting, clutch operation). This is carried out in order to compensate for the resulting low delivery rate of the primary pump and to ensure a constant oil pressure as well as optimal cooling and lubrication of the transaxle components. In start/stop mode with the engine off, all actuators return to their basic state under no load which means that no gear changes can be made and the dual clutch can no longer be actuated. In order to minimize the resulting delay between a start-off request and the start-off time, the electric oil pump provides the required oil pressure before the actual start-off process. In certain driving conditions (e.g. frequent start-off on uphill slopes or when driving with a trailer), the clutch needs to be cooled by an increased oil flow. The TCM deter-mines whether this is necessary based on the transaxle fluid temperature at the clutch plates. The increase in flow is also achieved by activating the electric oil pump.