SuperTurbo Technologies Inc. (formerly VanDyne SuperTurbo) has appointed Ricardo Performance Products to support the first phase of commercial industrialization of the SuperTurbo system—a novel planetary traction drive that enables high speed power transfer to and from a turbocharger shaft, offering significant driveability and fuel efficiency benefits for large trucks.
The SuperTurbo features a novel mechanical transmission that links the turbo shaft to the engine drive. This enables power transfer to and from the turbo shaft that is not possible with a normal turbocharger.
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.
During transient operation, the SuperTurbo will behave like a supercharger and draw mechanical energy to accelerate the turbomachinery for improved engine response. Unlike a traditional supercharger, the SuperTurbo also receives transient power from its turbine.
The net effect is both a fast transient response and a more efficient power draw for supercharging. The system also provides efficiency benefits to the engine.
During operation at higher engine power levels, the turbine of the SuperTurbo captures any excess energy from the exhaust above that needed to drive the compressor to provide boost pressure to the engine. In this operating condition, the system operates in turbo-compound mode, providing surplus power to the engine crankshaft, thus improving fuel efficiency.
The precise control over air flow allows the engine manufacturer to tune and control the optimal combustion parameters and reduce particulate emissions. Likewise, NOx emission reduction is enhanced through bypass enabled higher aftertreatment temperatures and improved transient and steady state EGR control.
Under the new contract, Ricardo will support SuperTurbo Technologies by providing product industrialization expertise to help in planning the route to commercial manufacture of the SuperTurbo system.