Rotrak - Supercharging Innovation
Variable drive supercharger
Technology
The key issue facing the high-volume automotive industry is CO2 emissions and fuel consumption – legislation and consumer demand are compelling vehicle manufacturers to reduce CO2 emissions and produce 'green' vehicles, whilst improving vehicle performance.
Engine downsizing is central to achieving this goal. Compared to a 'standard' engine, a 'downsized' engine has fewer cylinders and a smaller swept volume, and hence, with lower frictional and pumping losses, is more efficient. In order to maintain performance from a smaller engine, a pressure-charging device is applied – either a turbo- or supercharger.
Although widely used, existing pressure-charging or 'boosting' solutions have shortcomings, most prominent of which is the need to provide boost at low speed whilst also delivering sufficient boost at high speed.
This represents a distinct opportunity for Rotrak. The joint venture brings together two unique and proven technologies - Torotrak's compact variable drive technology and a novel compressor technology developed by Rotrex - to provide a compact, cost-effective and power-dense variable drive supercharging solution. This approach will enable the CO2 reduction and fuel efficiency benefits from engine downsizing whilst still providing the large engine performance 'feel'.
By combining a centrifugal supercharger and traction epicyclic with a variable ratio full-toroidal traction drive, the new technology will deliver performance and customer satisfaction levels which are not available from current pressure-charging solutions. Providing high torque at low engine speed and excellent transient response, Rotrak's solution will enable the efficient operation of the supercharger across the whole engine speed range, giving engine designers complete control over the compressor speed to overcome key technical challenges associated with current turbocharging and supercharging systems. Rotrak's technology has the ability to outperform the most sophisticated current systems when fitted to small engines, and the venture's studies indicate that the system can reduce the low speed 'lag' that most vehicle manufacturers are working to overcome in their engine downsizing work.
Rotrak is currently working on a jointly funded prototype programme to demonstrate the capability of the technology in vehicle.
