R-R acquires new turbocharging technology

Rolls-Royce has acquired from G+L innotec the exclusive rights to use a new technology for the electrically-assisted turbocharging of off-highway combustion engines in the power range above 450 kW. This new invention from G+L, a development and engineering services provider based in Laupheim in southern Germany, is protected by patents and has not been available on the market to date. Rolls-Royce plans to offer engines of its MTU brand with this technology as of 2021. “Electrically-assisted charging is a milestone on the way to the hybridising of the engine. Using this technology, it will be possible for us to develop agile, low-consumption engines,” said Dr Johannes Kech, director of Development Turbocharging & Fluid Systems at MTU. MTU and G+L innotec will be co-operating closely to complete the next stages of development of the technology.

Electrically-assisted turbocharging

The system consists of an electric drive combined with a traditional turbocharger developed and manufactured by MTU. As a result, the turbocharger can be accelerated electrically and the charge pressure built up earlier. In operating conditions when the energy required for a faster charge pressure of the turbine would normally not be sufficient, it is also possible to supplement it with the aid of the electric drive. The technology will allow MTU to increase significantly the acceleration of the load response capabilities of the engine, for example in generator drives and marine engines. In addition it will also be possible to reduce the engine’s fuel consumption and emissions in a variety of different applications. Due to the improved load response, emergency standby gensets will be able to deliver their full output faster than was previously the case. The technology can be applied to both diesel and gas engines.

Operating principle

To provide the turbocharger with electrical assistance, a permanent magnet is installed upstream of the compressor wheel and the electrical winding is integrated into the casing of the compressor. With this arrangement, the air drawn in by the compressor is not obstructed, and at the same time the electrical components are cooled by the air. The special feature of this arrangement is the large gap between the magnet and winding. This so-called media gap motor requires specially designed power electronics. This ensures that there is no aerodynamic impact on the charger and also that existing chargers can be adapted easily to enable them to make use of this technology.

First applications

As a result of its collaboration agreement with G+L innotec, MTU has equipped turbochargers with this electric drive and has carried out component tests to determine its possible potential. In the next stage, the two companies will set up series production, with the aim of launching engines equipped with this technology onto the market by 2021. The first applications considered suitable for these engines include emergency gensets, land vehicles and seagoing vessels.