MTU engines to use electrically assisted turbocharging

25 Sep 2017
The 'media gap motor' enables electrically boosted charging without interfering with turbocharger aerodynamics

The 'media gap motor' enables electrically boosted charging without interfering with turbocharger aerodynamics

A new turbocharger technology that will improve acceleration, fuel consumption and emissions will be deployed on MTU high-speed engines after parent group Rolls-Royce acquired the rights from G+L innotec.

The electrically-assisted charging system enables a turbocharger to be accelerated electrically and charge pressure built up earlier. This allows for engines with faster dynamic response, as well as enabling flexibility to improve fuel consumption and emissions.

Rolls-Royce has secured the exclusive rights to use the technology for off-highway combustion engines of more than 450kW. It has identified ships, emergency gensets and land vehicles as first applications for the technology.

“Electrically-assisted charging is a milestone on the way to the hybridising of the engine,” said Johannes Kech, director of development turbocharging & fluid systems at MTU. “Using this technology, it will be possible for us to develop agile, low-consumption engines.”

MTU has already equipped turbochargers with the electric drive and carried out component tests. The partners plan to prepare the new products for series production, with engines using the technology to be launched from 2021.

The electric driver proposed by G+L innotec comprises a permanent magnet upstream of the compressor wheel, with the electrical windings integrated into the casing of the compressor. This ‘media gap motor’ requires specially designed power electronics which are cooled by the intake air.

The large gap between the magnet and windings mean that air drawn in by the compressor does not affect the aerodynamics of the charger, and that existing chargers can be adapted easily to make use of the technology.

The video below features a presentation on G+L innotec's electrically-assisted charging system Cross-Charge, on which the new technology will be based.