Responding to calls from motorsport regulators for improved efficiency and more road car-relevant technologies in future Formula 1 cars, Torotrak plc and racing transmission specialist Xtrac Ltd. partner to develop a new brake-energy recovery system for racing vehicles.

Similar in design to a continuously variable transmission and based on Torotrak’s patented torodial traction drive variator, the new kinetic energy recovery system (KERS) revolves around a unique mechanical flywheel concept, which captures, stores and subsequently discharges a moving vehicle’s kinetic energy, Torotrak says.

For F1 cars, this means wasted heat energy is captured under braking and released back into the drivetrain to aid in acceleration.

“We are delighted to be working with Xtrac on this exciting new application of our transmission technology, to provide a highly efficient KERS solution for initial application in motorsport, but with a clear opportunity to apply the system in mainstream road cars to provide performance, economy and greenhouse gas emission benefits,” says Torotrak CEO Dick Elsy.

Although highly-advanced, F1 cars recently have come under fire for their excessive fuel consumption and failure to serve as effective test beds for mainstream automotive technologies.

In response, Max Mosely, president-Federation Internationale de l’Automobile (F1’s sanctioning body), and Burkhard Goeschel, chairman-Grand Prix Manufacturers Assn., which includes auto maker competitors such as BMW AG, Honda Motor Co. Ltd. and Mercedes-Benz AG, agree to a new regulatory framework for 2009 and beyond for improving the environmental image and technological relevence of the world’s premier racing series.

“We will make research work in F1 more road-relevant,” Mosely says. “We will move F1 from the technology of the 20th century to that of the 21st century, to move away from F1 being labeled as a dinosaur.”

In addition, the new FIA rules will seek to better integrate manufacturers, as the individual racing teams will relinquish some of their involvement at the FIA management board level and be replaced by representatives of the participating auto makers.

In addition to BMW, Honda and Mercedes, other auto maker’s involved in F1 competition include Ferrari SpA, defending 2-time champion Renault SA, Toyota Motor Corp. and Dutch sports car maker Spyker Cars NV.

Although still in development and without any customers, the Torotrak flywheel-variator KERS system provides mechanical efficiency in excess of 90%, the company says, while also serving as a more compact, efficient, lighter and environmentally friendly technology than battery-based hybrid-electric systems.

The variator, itself, weighs less than 11 lbs. (5 kg), Torotrak says.

Under the license agreement, Xtrac is granted permission to design, manufacture, assemble and distribute components or complete variator systems. Torotrak will provide the KERS control systems, while the individual F1 teams and their suppliers will develop the special flywheels and associated components.

The benefits of KERS in F1 cars, which can generate upwards of 800 hp at 19,000 rpm from their 2.4L V-8s, include improved fuel economy and an extra boost of acceleration for passing maneuvers and exiting corners.

Other forms of motorsport also could benefit from KERS-type energy recovery systems, Torotrak and Xtrac say, as could high-performance road cars, which are susceptible to changes in mandated emissions and fuel economy requirements.

In real-world conditions, a variator-flywheel system would be most valuable in stop-start driving situations, where the stored kinetic energy could assist in acceleration while simultaneously reducing excessive fuel consumption and carbon dioxide emissions.