The latest third generation of GETRAG dual-clutch transmissions features electro-mechanic shift drums for shift actuation and electro-hydraulic pump actuation for clutch actuation. The pump actuators integrate a pump and the electric motor driving it. These modules can be flexibly placed anywhere within the transmission. Pump actuation technology was launched with the 7DCT300 and is gradually being introduced in additional dual-clutch and hybrid transmissions.
The dual-clutch is more demanding as it needs to match the engine torque. It is the only frictional element in the load path of a dual-clutch transmission. With its on-demand smart actuation, GETRAG has managed to develop an extremely economical on-demand hydraulic system for activating the clutch. It uses pump actuators that only provide as much hydraulic pressure as the driving situation requires. By way of example, the power requirement for operating the clutch with the 7DCT300 is only 16 Watt in the NEDC. A further advantage of the pump actuators is that modules can be arranged flexibly in the transmission and used for different transmissions.
The total power consumption of the 7DCT300, including changing gear and transmission control unit, depending on use in the NECD is around 30 Watt. Smart actuation is used in GETRAG dual-clutch and hybrid transmissions. In both cases it contributes significantly to efficient automation.
Combined with the 7DCT300, Smart Actuation requires a mere 30 Watt of electrical power on average in the NEDC. This low consumption does not have any significant effect on fuel consumption, thus preserving the high efficiency of manual transmissions with dual-clutch transmissions. In practice, an intelligent shift strategy can even help to reduce real-life fuel consumption.
The modular design of Smart Actuation is another advantage: pump actuators as well as the shift drums belong to a common Corporate Transmission Architecture, meaning they can be used across all of the latest dual-clutch and hybrid transmissions. Technical progress effects every member of the transmission portfolio, and product variants can be designed by modifying the software instead of having to develop new hardware. These advantages will become even more crucial in the future, as they can be seamlessly transferred to hybrid transmissions.