Investigation into the potential of engine variabilities combined with e-fuels for achieving zero impact emissions

• Applicant: Professor Dr.-Ing. Michael Günthner
• Subject Area: Hydraulic and Turbo Engines and Piston Engines
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562579204

The proposed research project aims at the investigation of the fundamentals of a low-emission combustion process for engines operating with controlled homogeneous compression ignition (HCCI) in the entire engine operating range. The primary focus of the research work is the expansion of the operating range with homogeneous compression ignition (particularly at high engine loads) based on the utilization of the advantages of synthetic fuels. The extension of the operating range is to be achieved in a way that operating mode switching is avoided in practical operation. A further target is to keep raw emissions in the entire operating range at the lowest possible level, i.e. the expansion of the operating range should explicitly not be achieved at the cost of significantly increased raw emissions and thus increased effort for exhaust gas aftertreatment, as this is the case with previous approaches e.g. relying on diffusion combustion in the upper load range. On the basis of previous research, OME (polyoxymethylene dimethyl ether with a chain length of 3 to 5) and n-butanol were selected as the most promising candidates for synthetic fuels to be investigated, as they promise ultra-low emissions together with advantageous physicochemical properties for the intended combustion process. The investigations will be carried out using a highly variable single-cylinder research engine developed in previous projects at the chair, featuring valve-specific variabilities of the opening and closing characteristics of the gas exchange valves as well as a continuously variable geometric compression ratio. This allows the systematic investigation of the relevant influencing parameters for optimizing combustion behavior in homogeneous compression ignition operation and maximizing the possible operating range with this combustion process. The experimental investigations on the engine test bench are accompanied by numerical simulation (1D and 3D) to improve the understanding of the internal engine processes and to enable an even more focused optimization. Furthermore, MBS and FEM tools are used to optimize the valvetrain design, complemented by experimental investigations on a component test rig for valvetrains.

• DFG Programme: Research Grants