Innovative High-Speed Traction Drive
At the heart of the SuperTurbo™ is a unique planetary traction drive that enables power transfer to and from the turbo shaft. Turbochargers regularly run at speeds in excess of 100,000 RPM, where more traditional transmission components such as gears struggle to operate.
Instead of relying on direct contact of gear teeth, the traction drive utilizes a NASA developed technology of smooth rollers that transmit torque through a special traction fluid and can operate at very high rotational speeds. The rollers are pushed together to generate high pressures that causes a pseudo-phase change of the traction fluid so it will resist shear forces and transmit higher levels of torque. The added complexity of the traction drive transmission is offset somewhat, in that special designs of the traction drive eliminate the need for any sort of bearings directly supporting the high-speed turbo shaft. These extremely high-speed bearings are a major failure point in conventional turbochargers, but are not needed in the SuperTurbo.
In addition to the high-speed planetary traction drive, a continuously variable transmission is used in most applications to enable precise control over the speed of the turbo shaft to provide desired air flow and boost pressure levels for the engine. The reduction in turbo lag also reduces the design requirement for low-inertia turbine and compressor wheels, enabling more flexibility in the design for the turbo-machinery for higher efficiency.