Q&A: Dr. Juergen Greiner

ZF's head of development for passenger car transmissions explains what the future holds for the technology

Increasing the number of ratios is a simple method to improve overall vehicle efficiency – but how far can this be taken, will we see 11- 12- or more speeds or is this unnecessary?

Needless to say, we have been researching whether passenger car transmissions could soon have ten or more gears for a long time. We are well supported in this by good synthesis simulation tools, which can simulate all possible engine/transmission combinations. Development has, however, already reached its limits. A ratio spread much higher than the spread of our current transmissions would rather be counterproductive as hardly any potential can be unlocked on today's combustion engines with the required high efforts put into the transmission. The air for future developments becomes thin. And the further we move toward electric vehicles, the fewer gears we will need in electric drives.

…linked to this is increasing connectivity – what impact could better connected vehicles have on transmission technologies?

Apart from road safety, efficiency in particular will be further optimised by the increasing level of networking between vehicles, the cloud and traffic infrastructure. Some applications of the transmission control already use GPS data to optimise shift strategies and to downshift on time or to change to coasting, for instance. In hybrid vehicles in particular, an intelligent drive management is essential for efficiency.

At present there are numerous transmission technologies – manual, CVT, DCT, torque converter, automated manual – how do you foresee the market developing in the future, will we continue to have the same variety of technologies?

There will continue to be different transmission systems on the market. In the course of future partial electrification of the transmissions, efficiency, compact design and low weight of the planetary gearset are clear assets of this transmission type from our point of view.

Next week we hear from Getrag on what it expects the trends in transmission technologies to be

tags: ZF Transmissions