The GESIR project, carried out from 1 July 2019 to 31 March 2023, aimed to raise the efficiency of gas engines while keeping wear and emissions within acceptable limits. A six‑cylinder, turbo‑charged, intercooler‑equipped engine originally designed for diesel was converted to run on gas. The engine was mounted on a full‑engine test rig and operated under a new control and monitoring system developed by the project team. The target performance for mobile applications was an increase from 235 kW to 295 kW, achieved by raising the cylinder peak pressure to 160 bar and limiting the exhaust temperature to 800 °C. For stationary use the power target was raised from 140 kW to at least 200 kW, while the required cylinder‑head life of 25 000 h was maintained. The engine’s durability was also improved: the mobile life target was extended from 800 000 km to 1 500 000 km.

To meet these goals the project focused on three technical fronts. First, tribologically adapted materials were developed for valve seats, valves and valve guides. Thermometric measurements of the valve guides and seat rings during operation revealed the temperature distribution close to the combustion chamber, and subsequent hardness tests quantified the reduction in material hardness caused by thermal loading. Extrapolation of wear data, combined with different lubricants and ignition angles, showed that the new materials could sustain the higher loads without excessive wear over the projected lifetime. Second, thermally stable lubricants were formulated and tested. The lubricants were evaluated in the same high‑temperature test rig, and their performance was benchmarked against conventional oils. The new lubricants maintained viscosity and oxidation resistance at temperatures approaching 800 °C, thereby reducing wear on the valve train. Third, new mixture‑formation concepts and precise operating‑condition tuning were developed in collaboration with MAN. These concepts optimized the fuel‑air mixture and ignition timing to keep the combustion temperature and pressure within the limits that the improved materials and lubricants could tolerate.

The project also advanced testing methodology. The Institute for Automotive Technology (IAVF) closed gaps in its existing test‑methodology portfolio by introducing a cost‑ and time‑efficient Rapid‑Nondestructive‑Testing (RNT) technique suitable for gas‑engine systems. This technique was successfully applied to engines operating at exhaust temperatures of 850 °C and peak pressures of 160 bar, extending the application spectrum of IAVF’s testing methods. Optical measurement techniques were integrated to evaluate wear on high‑temperature materials, improving the predictability of tribological performance under extreme conditions. The interdisciplinary team, comprising researchers from Fraunhofer Institute for Material Mechanics (IWM), Bleistahl Production, Fuchs Lubricants, and MAN Truck & Bus, combined expertise in material science, lubrication, engine design and testing. The project was led by Dr. Ing. P. Berlet of IAVF, with project management provided by TÜV Rheinland Consulting.

Funding was supplied by the German Federal Ministry for Economic Affairs and Climate Action under the project number 19I19006A. The collaboration achieved its objectives: it closed methodological gaps, delivered a cost‑effective RNT testing technique, extended the testing envelope to high temperatures and pressures, and produced improved materials and lubricants that enable higher engine efficiency without compromising durability. These results support the European Union’s Renewable Energy Directive III target of 45 % renewable energy by 2030, as gas engines running on hydrogen or methane can contribute significantly to that goal.