8-speed double clutch 8dt from zf in focus

The new Porsche Panamera is the first (of many) to use the new ZF dual clutch transmission. Developed jointly by the sports car manufacturer and the supplier, the 8-speed dual clutch transmission has an integrated hybrid option. The transmission, known internally as 8DT, is already used in the Panamera Plug-in Hybrid with its maximum output of 100 kW.

8DT with hybrid module already in use in the Panamera

According to ZF, however, the hybrid module is optional and therefore does not have to be installed. The 100 kW hybrid module can be used “without increasing the length” compared to the previous 7DT sports transmission. Conversely, the eight-stage dual clutch transmission is even more compact than the (old) seven-stage transmission. Designed for vehicles with all-wheel or rear-wheel drive, the front axle can also be operated using the efficient hang-on principle.

“In the new 8DT sports transmission, we combine lightning-fast gear changes and very high efficiency, including fully electric driving, with the flexibility for different variants in a tight installation space – without compromising.” Jürgen Greiner, Head of Development Car Transmissions at ZF Friedrichshafen AG

Compared to its predecessor, the power loss has been reduced by up to 28 percent. The main focus was particularly on performance, with the first six gears fully designed for the best acceleration. Gears seven and eight, however, are designed as “overdrive”. Speed ​​and fuel consumption should be reduced equally.

Compact design and new mechanical solution

The transmission is divided into three different torque classes. The basic gearbox and the wheelset always remain unchanged. A maximum of 1,000 Nm torque is possible with the 8DT. In order to achieve the compact design, a new gear set concept with two countershafts and a summing shaft was designed. The multiple use of the fixed gears results in fewer gear planes and the basic transmission is shorter. This means that the hybrid module can be used without increasing the length.

The hybrid module of the ZF 8DT

The hybrid module integrates torsional dampers, separating clutch, actuators and the electric machine and is thus placed in the clutch housing. The peak output is 100 kW, while the continuous output is 55 kW. With 400 Nm torque, a vehicle – such as the Panamera 4 E-Hybrid – can accelerate up to 140 km / h purely electrically.

For the all-wheel drive variants, ZF includes an all-wheel distributor that sends the torque to the front axle drive according to demand. The hang-on all-wheel drive clutch is a wet-running multi-plate clutch that is operated in continuous slip.

Photos: ZF Friedrichshafen AG