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Torotrak wins $340K funding for V-Charge project; supercharger integrated with mechanical variable speed drive

Torotrak PLC has been awarded a grant of £205,000 (US$340,000) under the Technology Strategy Board’s Smart scheme to develop an application specific, production intent version of its V-Charge technology. With additional support from a major OEM and a Tier One supplier, Torotrak will work in partnership with the University of Bath Powertrain and Vehicle Research Centre to optimize the technology around an advanced production engine.

Torotrak’s V-Charge technology combines a proven compressor with Torotrak’s compact variable drive Click to enlarge.

V-Charge integrates a supercharger with a mechanical variable speed drive to address a key barrier to engine downsizing by providing near instant response at any engine speed. This ability allows the boosting of smaller engines across their full operating range with a single V-Charge device, unlike an electric supercharger that would require the addition of a turbocharger to achieve the same spread of performance, the company claims.

The opportunity to fully exploit the potential of V-Charge by manipulating various engine parameters, such as valve timing, injection modes, and exhaust gas recirculation means we can develop the optimum production-feasible installation for a homologated vehicle. This allows us to evolve a purpose-made unit that brings the technology much closer to market than previous proof-of-concept hardware.

—Andrew De Freitas, Torotrak’s product director

To optimise V-Charge for the intended application, extensive modeling and validation will be carried out by the University of Bath using simulation based on models from the supporting OEM. As the variable drive is scalable for different power requirements and the ratio spread can be adjusted to suit the application, a purpose-designed unit will be developed and multiple prototypes produced.

One system will allow assessment and demonstration in a baseline vehicle, while another is intended for evaluation in a larger vehicle, where current boosting technologies struggle to provide acceptable performance. Delivering the driver feel of a much larger, more powerful engine in this context would be considered a breakthrough and could set new industry standards for truly driveable downsized engines, the company hopes.



A mechanical transmission to drive engine auxiliaries instead of using electric drive has an inherent provision for higher efficiency than the latter. This is on the condition, of course, that the variable speed drive has high efficiency, which seems to be a feature of the Torotrak variable speed drive. Although this application seems to be focussed on omitting the turbocharger, two-stage charging by using a turbocharger would still be an interesting option to further enhance power density and downsizing potential.


This is probably better engineered but the 1957 Golden Hawk Studebaker (remember them?) offered a Paxton supercharger that had a variable speed drive. Is anything ever new? Of course Studebaker also offered electric vehicles about 110 years ago (1902-1912).

Personally, I think that an electrically driven turbocharger is a better idea. At low power, you drive the compressor to produce more boost. At higher power, you pull electric power out of the turbo to control the boost and put the excess power back into the battery or drive other electric auxiliaries.


Ditto your comment, sd. With switched reluctance technology in the turbocompressor motor/gen and ultra caps for energy storage, you have a lighter and less expensive approach to hybridization that still yields significant performance improvement. I have seen roller traction drives like the one pictured in the Torotrak for such applications as aircraft constant speed drives; none of them seemed to have good reliability.

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