Vaircon - Continuously variable air-conditioning drive for PSV

Lead Participant: Magnomatics Limited


This project is focussed on the development of a Magnetic Continuously Variable Transmission (mCVT) system that is optimised for automotive ancillary drive applications. CVT systems have benefits in hybrid vehicle drive trains where they are used to ensure that the engine is always operating at maximum efficiency. By exploiting this flexibility, significant fuel/emissions benefits can be achieved. mCVTs can also be used to drive ancillaries (e.g. air-conditioning (AC) compressors, pumps, etc). In such applications the mCVT fits onto the engine belt driving the ancillary with engine power, but at an optimum speed, independent of engine speed. By doing this the AC compressor can be operated at the speed required by the cooling requirements, rather than that dictated by the engine speed via a fixed ratio. This leads to significant reduction in engine parasitic loss with consequent benefits in terms of CO2 and fuel consumption. The flexibility of the system can be extended to give AC function even when the engine is off. This important feature allows continued AC while the engine stop/start feature is enabled, preventing the driver from disabling the system to maintain AC and thereby negating all fuel and emissions benefits provided. Furthermore, the engine-off function allows the system to act as a "parking cooler" for commercial vehicles, deleting the secondary cooling loop on the roof of the cabin.

Magnomatics is developing a much larger, main powertrain, mCVT system for hybrid vehicles. This ongoing development of the main powertrain system is being used to accelerate this smaller spin-off product where knowledge will be transferred to the technical development.

A key differentiator for this system is that in order to be competitive it must have reduced cost and therefore function. This is achieved by combining two electrical machines present in the existing Magnomatics mCVT systems into a single unit using innovative magnetic field superposition techniques.

This is a patent pending key innovation, which provides a more compact, more efficient, simpler and cheaper machine than any competing power-split system.

This project will provide a working, tested prototype. The system will be vehicle fit ready for evaluation on a fleet of buses that are currently awaiting retro-fitment of emissions reduction technology by Eminox. Ultimately the entire project will see the UK manufacture and retro-fitment of the systems, with export opportunities (thousands off) to an existing transport provider already being established.

Lead Participant

Project Cost

Grant Offer

Magnomatics Limited, Sheffield, UNITED KINGDOM £226,446 £ 158,512


Eminox Limited, GAINSBOROUGH £60,277 £ 30,138


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