A revolutionary transmission could make the gear stick a thing of the past. The TRUFUS project was launched by Belgium technology firm Mazaro to accelerate the development of its innovative continuously variable transmission (CVT). Vehicle transmissions allow drivers to change the torque and speed that the engine delivers to the wheels, by altering the ratio between the two. Regular transmissions achieve this by switching between a set of fixed gear ratios, whereas CVTs can deliver any gear ratio between the minimum and maximum available. CVTs offer greater efficiency, but nearly all these gains are lost due to increased friction and slippage in the mechanism, which relies on toothless conical pulleys, typically connected by a belt. TRUFUS is a pioneering concept which uses a beltless set of traction wheels that do not slip, offering very high efficiency without any wear at all.
New and improved
“Current transmission technology is fully optimised, so any possibility for further reductions in emissions is very small,” says TRUFUS project coordinator Filip De Mazière. “Our idea is to introduce a completely new principle of transmission, gaining much higher savings in energy consumption.” CVTs are also simpler than regular transmissions, and so cheaper to produce. “The advantages are so big that when we explained it to vehicle manufacturers many said it was not possible,” says Mazaro marketing officer Caroline De Dijcker. “As always you need to prove it in the real environment.”
Mazaro placed the prototype transmission in a 3.5 tonne, electric light commercial vehicle. By always keeping the motor on its highest efficiency curve, the team boosted the truck’s driving range by 16.8 %. The increased control of power delivered by the motor also increased the vehicle’s top speed by 50 %, from 80 to 120 km/h. De Mazière says their focus is on customers looking for fuel and emissions savings, such as public transport. “Commercial vehicles like buses, garbage trucks and delivery vehicles are working 12 or even 24 hours a day, so efficiency is very important,” says De Dijcker. Mazaro hopes to see the transmission in use from 2022 as it filters in on new vehicles joining the road. Retrofitting the transmission to existing vehicles would be too expensive to be commercially viable.
Getting through ‘death valley’
The project received support from the EU through the societal challenges and green transport Horizon 2020 goals. “We had to overcome that death valley, where the technology is ready but you need large investments to bring it to market,” says De Mazière. “It’s very difficult to attract investment when you have technology on the bench and not yet in a visible thing like a truck.” De Dijcker adds that EU support also enhanced the credibility of the company and attracted other investors to the project. Mazaro is now working to improve the efficiency of the technology even further, recently cutting the energy consumed by the transmission control system from 1 % to 0.17 % of the transmitted energy. The company also plans to diversify the business portfolio by pursuing applications for the technology across a range of industries, such as turbines and off-highway vehicles.
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