Torotrak Buys Stake in Flywheel Maker

U.K.-based Torotrak plc has acquired a 20% stake in Flybrid Automotive Ltd., a privately held British developer of high-speed flywheels used in vehicles to store energy recovered during braking.

Torotrak, which makes a unique toroidal continuously variable transmission, has the option of extending its $4.5 million investment and buying Flybrid outright by the end of this year.

Separately, Indianapolis-based Allison Transmission Inc. boosted its stake in Torotrak to about 13% by agreeing to buy $3.8 million in new shares in the company.

Allison also will pay Torotrak $9.1 million to continue its exclusive license to make and sell Torotrak transmissions for use in commercial vehicles. The American company acquired a 10% stake in Torotrak in 2009.

The Flybrid system uses a flywheel measuring about 10 inches in diameter that spins at more than 60,000 rpm. The unit connects to a vehicle through a special kinetic energy recovery system (KERS) transmission. The company, which was founded by two Formula One racing engineers, says its system delivers fuel savings similar to a hybrid powertrain costing three times as much.