Ecological jet engines: German top manufacturer MTU’s way

Rethink flying: on the way to zero emissions

Civil aircraft and engines have to become even more economical, ecological and quieter. The requirements are becoming more and more ambitious: zero emissions is the major goal of aviation.
MTU Aero Engines is facing up to this responsibility and has never before had such forward-looking answers as it does today: Germany’s leading jet engine manufacturer is working in parallel on evolutionary engine concepts for tomorrow and revolutionary ideas for the day after tomorrow. The development work has two thrusts: the evolutionary further development of the gas turbine based on the geared turbofan combined with revolutionary drive concepts as well as electrification of the drive train as completely as possible in order to be as emission-free as possible in flight. Of all the concepts considered, the conversion of hydrogen into electricity with the aid of a fuel cell has the greatest potential for MTU.

Evolutionary and revolutionary concepts

The geared turbofan is at the center of the evolutionary development of the gas turbine. The aim is to reach its full potential. MTU is concentrating on the further development and optimization of its high-pressure compressor and high-speed low-pressure turbine components. At the same time, the engine experts are working on combining the tried and tested and further optimized geared turbofan with completely new technologies. Two concepts emerge: In the composite cycle approach, the conventional high-pressure compressor system is to be supplemented by a piston compressor and motor; with the WET engine concept, a steam power process is integrated into the gas turbine process.

More than 20% less CO2 emissions and fuel consumption

WET stands for Water-Enhanced Turbofan. Practically, the heat produced by the jet engine is channeled into a turbine compressor in the body of the aircraft, and the bottom of the wing. Adding water, the compressor turns the heat into steam, which is injected into the Turbofan jet engine thus reducing a mission by 25% and noise by 50%. Fuel consumption reduction should also be around 20%.

MTU water enhanced turbo fan technology
Flying with water vapor: Wet combustion would significantly reduce carbon dioxide and nitrogen oxide pollutant emissions.

The revolutionary concepts also include electric drives. MTU is focusing on the hydrogen-powered flying fuel cell, i.e. a fuel cell-based drive. To this end, it established its own team of experts and signed a Memorandum of Understanding with the German Aerospace Center (DLR) at the beginning of August: The partners want to jointly develop and validate a fuel cell drive train. A Do228 serves as a flight demonstrator.

Sustainable, alternative fuels

MTU attaches great importance to sustainable, alternative fuels (Sustainable Aviation Fuels = SAF), because: the ambitious climate protection goals for 2050 can only be achieved with the use of sustainable, regenerative fuels. The future is likely to belong to power-to-liquid (PtL) and sun-to-liquid (StL) fuels that use green electricity or solar energy to produce the fuels. SAFs meet the specification for aviation fuels and can be used immediately in the existing drop-in infrastructure. In the longer term, hydrogen is an ideal fuel. Compared to PtL fuels, hydrogen can be produced more efficiently and cost-effectively, but requires a new infrastructure and new aircraft designs.