Developing a transmission for Formula E
In 2021, it was announced that Ricardo and DS Performance would be extending their partnership to develop a transmission solution for the third generation of electric vehicle for Formula E. This technology has appeared in the vehicles of the DS Penske and Maserati MSG Racing teams. The ninth season began early in 2023 and saw the debut of this new vehicle specification racing in a 16 round World Championship, starting in Mexico City.
Challenge
Development of performance within a Formula E car is restricted by regulation to a few key areas, one of which being the powertrain. This includes the electric motor, power electronics and gearbox. Competitive advantage is achieved by optimising (to fractions of a percentage) the efficiency and performance of these systems. DS Performance needed a transmission partner to support the development of a Formula E gearbox meeting the unique demands of electrified racing.
DS Performance first approached Ricardo to optimise a transmission solution in 2016. They required a solution which matched the series regulations, was sensitive to the unique requirements of electric powertrains, all whilst ensuring maximum performance on the track.
Approach
Long before any Ricardo product raced in competition within Formula E, a technical partnership was established with DS Performance to understand the needs of the customer and the demands of the transmission. During the development phase Ricardo used in house software modelling and compared the output to real world bench testing efficiency results to support iterative refinement of the micro geometry, lubrication management and bearing application.
Ricardo’s engineer – to – engineer relationship with DS Performance means that challenges are comprehensively understood, issues quickly resolved, and world leading performance is delivered.
The designs were refined at concept level to minimise predicted losses through the gearbox. This allowed as much power as possible to be delivered to the rear wheels. Test gearboxes were then carefully analysed at DS Performance headquarters to validate efficiency predictions and feedback results for further improvements.
Season five saw the launch of the second generation of electric vehicles. A battery with more power and a larger capacity would provide a top speed of 280 km/h and meant that, for the first time since the series began, the race could be completed with a single car.
DS Performance needed a new transmission to accommodate these new specifications. Building on the learnings from the first-generation vehicles, Ricardo developed a fully optimised single-speed gearbox with a two-stage reduction arrangement to match the high motor input speeds to the required vehicle speed.
The transmission was tailored for maximum performance and efficiency. The gears were made from aerospace steels to reduce the weight of the transmission and the tooth micro-geometry refined for maximum efficiency. The casing was also optimised for minimum weight.
Maximising performance and reducing power loss was also key to the success of the transmission. Careful consideration was given to the differential design to enable maximum performance. The oil system, rolling-element bearing design, casing design, and radial oil seals were all specified to reduce power losses through the gearbox.
Results
DS Performance are double teams and drivers champions in this highly competitive electric racing in part due to the highly efficient transmission developed with Ricardo.
The DS Techeetah team went on to secure back-to-back Constructor’s Championship in season five and six. They also saw resounding success in the Driver’s Championship. Jean-Eric Vergne took the title in 2017-2018 and 2018-19, becoming the first series’ first repeat champion. António Félix da Costa then went on to win the 2019-2020 season, claiming the title with two races still to run.
Ricardo is pleased to have played its part in enabling DS Performance to achieve championship success. We hope this will continue with the third-generation designs appearing in the vehicles of the DS Penske and Maserati MSG Racing teams. The ninth season began in early 2023 and saw the debut of this new vehicle specification in Mexico City, the first event of a sixteen round calendar finishing in London later the same year.
Formula E is a catalyst not only help to decarbonise the motorsport industry, but also to refine the design of electric vehicles and improve the driving experience for everyday road car users all over the world.