The transmission can accelerate an EV from 0 to 100 kmph in 2.5 seconds
Austrian high-tech e-mobility company Kreisel Electric has developed a production-ready, automated 2-speed transmission for electric mobility applications.
The new transmission was developed in combination with an integrated powertrain architecture specially developed in cooperation with Sala Drive – both designed for high performance and torque ranges.
“We have set ourselves the demanding task of building an ultra-light, electric supercar based on a historic sports car as the ideal application for our transmission,” says one of the Kreisel Electric CEOs, Markus Kreisel.
“The challenge here is that there is nothing even remotely like a standard component available here, no matter where you look. So we developed the essential components ourselves on the basis of our own requirements profile,” Kreisel continues.
For example, the automated 2-speed transmission not only had to be able to guarantee unique acceleration values and top speeds, but also act as a reliable link between a high-performance powertrain and a correspondingly powerful and lightweight battery, which was also specially developed for the vehicle.
The sports car, which was already on show at Techno Classica in Essen in April 2017, sprints from 0 to 100 kmph in around 2.5 seconds, achieving a top speed of above 300 kmph. In addition, a single battery charge can easily provide a range limit of more than 350 km.
The transmission utilises an electric lube oil pump with integrated oil reservoir that self-enables on demand for maximum efficiency. This results in a massively reduced drag losses due to a friction-optimised bearing arrangement. Electromechanical gear synchronisation ensures the shortest torque interruptions through optimised torque and speed control of the electric drive during lightning-fast, 0.25-second gear shifts.
“In this way, any thermal impact by friction elements and possible wear effects on the shift components can be practically eliminated. A limited slip differential lock, which is also integrated, ensures uninterrupted torque transmission even in slippery road conditions. And last but not least, a modular interface that supports a wide range of applications for motor and transmission arrangements,” explains Philipp Kreisel, who is also a CEO of Kreisel Electric.
In a maximum expansion stage, e.g. through the use of more powerful electric motors, breath-taking output values of 600 kW and an input torque of up to 900 Nm can be managed in this way.
Using innovative approaches to complete vehicle integration, the centre of gravity of the lightweight sports vehicle was lowered even further to achieve optimum handling with a weight ratio of 37% (front): 63% (rear).
There is also a great deal of intelligence, variability and flexibility in the entire setup. A large number of sensors continuously monitor all relevant components and combine the collected data in real time in a transmission control unit (TCU).
The modular powertrain arrangements allow for one or two motors per axle just as easily as a single motor. And for applications that also require high torques, such as small and medium-sized transporters up to 3.5 tonnes or trucks and buses up to 15 tonnes, the automated 2-speed transmission can be easily be adapted to match.
All this is rounded off by the integration of the world’s leading battery solution from Kreisel Electric, with a nominal capacity of 54 kWh, which is exclusively used in the electric sports car.
“Thanks to our patented technologies, unique thermal management and the laser-welding process of the battery packs, we are now able to offer the lightest battery with the highest energy density for the most diverse applications, whether mobile or stationary. This in turn results in unrivalled, fast charging times, long ranges and a long service life of our battery solutions,” says Johann Kreisel, the third CEO in the Kreisel Electric group.