ZF Reveals more Information on Its Latest Transmission Solution
The latest 8-speed hybrid automatic
transmission, designed by ZF engineers, has already drawn a lot of attention
from major automakers, which translated into two major orders from BMW and FCA.
Now ZF is providing more information on its promising solution.
The modular design allows implementing
different types of hybrid drives with max power of 24 to 160 kW. The high-power
electronics are fully incorporated into the gearbox casing.
ZF engineers managed to realize this idea,
because this 8-speed unit was planned to become hybrid from the very beginning.
Earlier manufacturers used e-motors with top power flux rate instead of the
torque converters. Since the transmission casing, which was initially intended
for a converter, determined the transmission structure previous automatics were
heavily restricted in their electrical operating capacities.
ZF engineers eliminated this drawback by
designing a proper casing for more space-demanding and more powerful e-motor
integrated in the new gear shifting solution. Nevertheless, the external
dimensions of the unit stay the same. This is due to the fact that the new
transmission has got much smaller hydraulic control unit, thereby ZF engineers
managed to leave enough installation space necessary for the electrical and
electronic elements.
High-power electronics, which is now embedded in
the gearbox itself, comes as a great help in this situation. It is also said
that ZF engineers had to introduce a fresh cooling unit, because some of the
semiconductor power devices can overheat during operation. For automakers, the
incorporated power electronics provides 2 significant benefits: in one respect,
it helps to reduce the number of cables in the car, thereby increasing safety.
Moreover, the power electronics, which previously had the size of a shoe box,
no longer have to be fitted in the car. The assembly of the upcoming 8-speed
unit is no more complicated than that of a standard gearbox.
With the new e-motor, the electric driving elements of the PHEV are to be substantially increased. Even without the IC-engine, the max torque is 450 Nm – allowing fast speed-ups even in E-mode, for instance when overtaking other vehicles. ZF plans to launch the mass production of this 8-speed transmission in 3 years: initially the production will be concentrated in Germany and it is planned to later shift it to China and the US. An approximate amount of the two signed deals (with BMW and FCA) is estimated at € 15-20 bln, but there is no official info on this subject.
