High-efficiency air compressor for heavy-duty powertrains

HiComp2 is an Innovate UK project that was funded as part of the 15th Integrated Delivery Programme.  A collaborative research and development project between four consortium partners: Equipmake, HiETA Technologies Ltd, Bladon and IAAPS, its primary goal is to develop a high-speed, electrically driven two-stage compressor that is both lighter and cheaper and more efficient than current air compressor systems available in the automotive sector. The project is expected to be completed by end of Q1 2022.

Technical overview

The new unit in development combines a new high voltage inverter and electric motor (Equipmake) running on high-speed, low-friction air bearings (Bladon) with a pair of back-to-back centrifugal compressors (IAAPS). Inbetween the two compression stages, a 3D-printed intercooler (HiETA Technologies) conditions the partially compressed air from the first, ‘low pressure’ stage before feeding into the second, ‘high pressure’ stage compressor, for improved compression performance.

As the lead project partner, Equipmake is the system integrator and leverages its knowledge of electrical systems to develop the high voltage inverter and electric motor. Bladon brings its understanding of high-speed rotating machinery to develop and supply the air bearings, while HiETA is leveraging its expertise in additive manufacturing for the intercooler.

1D model of schematic compressor.

Expected outcome

By the end of the project, the consortium partners will have delivered a working pre-production prototype capable of matching the system performance of existing competitor products in a smaller, lighter, cheaper and more efficient package.

Expected benefits

On a large passenger vehicle such as a bus, the system mass/weight may not play a significant role, however as with all automotive transport solutions, space and packaging are almost always at a premium. Additionally, the shift to hybrid and full electric powertrains have placed emphasis on the ancillary systems which traditionally have been driven by fossil fuels; a high efficiency compressor such as this will make for an ideal replacement.

FEA (Finite element analysis) of the 1st stage impeller.

IAAPS’ role in the project

IAAPS and the University of Bath have a key role within the consortium, leveraging our expertise in turbomachinery to develop the compressor impeller and housing designs. We use both three-dimensional computational fluid dynamics as well as one-dimensional system-level modelling to optimise the design of both compressors and assist the partners with system integration, respectively.

Significance to the wider net zero transition

Almost every aspect of our lives will need to adapt to a net zero carbon future, and electric cars are a good example of how this may be achieved. However, it is much more difficult to electrify heavier vehicles, like trucks and buses, because of their need for much higher levels of energy. The new HiComp2 high-efficiency air compressor is designed specifically for medium- and heavy-duty powertrains. It replaces existing technology powered by fossil fuels with one optimised for larger electric vehicles. In this way, it will help to accelerate the transition to net zero transport.

Future application and rollout

Once in production, it is expected that the project lead Equipmake will introduce the unit on its customers’ fleet of electric buses, currently in development.