In the face of increasing social environmental awareness and targeted political initiatives such as the European Green Deal, interest in climate-friendly propulsion solutions for aviation is growing. To demonstrate the great potential offered by H₂ in aircraft propulsion, Bosch Aviation Technology, a subsidiary of Robert Bosch AG based in Vienna, has converted a conventional aircraft engine for operation with H₂ as part of an innovation project. The basic unit, a four-cylinder gasoline engine, comes from the Austrian manufacturer BRP-Rotax, a leader in the development and production of powertrain systems for the leisure and powersports sector.

"In implementing the feasibility study, we were able to draw upon the proven performance of the Rotax 916 aircraft engine and combine this with our many years of experience in the H₂ sector. Instead of developing an entirely new engine, we opted to modify an established engine design as we anticipate strong demand for this pioneering approach in future customer projects due to the time, cost, and approval advantages," explained Christian Grim, General Manager of Bosch General Aviation Technology GmbH, which has been transferring products, services, and technologies from the automotive sector to the aviation industry for over 15 years.

As part of a feasibility study, the experts from Bosch successfully completed the necessary modifications for H₂ operation on a 1.4-liter turbo engine in around four months. Thanks to their extensive development work on the engine test bench, they were able to significantly optimize the performance of the H₂ engine. All components for the H₂ system are based on volume-production developments from Bosch.

In its current project stage, the engine already delivers 115 kilowatts of maximum power and thus comes within around 2% of the basic gasoline engine. With a specific future development of a prototype, it will be possible to further increase the output.

As a result, the concept for future aircraft engines pursued by Bosch Aviation Technology could help to reduce carbon emissions in general aviation. The innovation project is thus in keeping with Bosch's strategic decision to intensify cross-segment developments of future drive and propulsion systems that will maximize the environmental compatibility and minimize the emissions of tomorrow's mobility.