Future: manual transmissions for electric cars
IT GOES ON Electric cars can do without a manual gearbox. With new technology from ZF, the speed can be increased up to three times that of a combustion engine. Sufficient elasticity is available at all times. The experts at ZF Friedrichshafen AG have developed a two-stage transmission for electric motors, each of which offers one of two advantages: either more range or a higher [...]
The experts at ZF Friedrichshafen AG have developed a two-stage transmission for electric motors that offers one of two advantages: either more range or higher speed.
In order to increase efficiency, ZF developed a new electric motor with an output of 140 kW (190 hp) and coupled it with a two-stage shift element. The unit is so compact that it also fits into smaller passenger cars.
The new drive with two gears, which are automatically shifted up or down at 70 km/h, provides up to five percent more range than the previous gearless drive.
Smaller and therefore cheaper batteries
Bert Hellwig, Head of System House E-Mobility ZF: "For the everyday use of electric cars, it is important to get as much range as possible from a single battery charge. Every one percent increase in efficiency translates into two percent more range. Car manufacturers can also benefit. A longer range allows them to use smaller and therefore cheaper batteries."
Strategies for better utilization
Other special strategies for making better use of the advantages of second gear for electric cars are also conceivable. If, for example, the gearshift program were linked to the information from the navigation device, it would always know where the next charging station is located. If the battery's energy supply is running low, the gearbox could switch to a particularly economical driving style in good time to reach the emergency power socket.
Torque or final speed
And Bert Hellweg mentions another advantage: "Until now, vehicle manufacturers have had to choose between a high starting torque and a higher top speed for electric drives. We are now resolving this conflict of objectives, as the new drive will be compatible with powerful and heavier vehicles - for example, passenger cars towing a trailer."
