The TEC4FUELS project, funded under the German federal program “Innovative Fahrzeuge” with the grant code 22000611, investigated the use of methanol as a renewable fuel for diesel engines. The research was carried out in collaboration with OWI GmbH, which supplied a dedicated hardware‑in‑the‑loop test bench that reproduced the full fuel‑delivery chain of a conventional diesel vehicle—from the tank and pre‑pressure pump through the high‑pressure pump (HDP), rail, and injector. TEC4FUELS performed a series of endurance tests on this system, varying methanol purity, additive concentration, and operating pressure to assess material compatibility, cavitation behaviour, and component durability.

Technical results show that the rail and in‑tank pump tolerated both pure methanol and methanol with additives without any critical failures. The HDP operated reliably at pressures up to 250 bar when additives of 1000 ppm and 2000 ppm were used, achieving continuous operation for 100 h and 200 h respectively. In contrast, tests at 800 bar—typical for conventional diesel fuel—led to cavitation in the HDP and injector, with failure times ranging from 5.5 h to 13 h. The pressure‑regulation valve (DRV) also suffered cavitation at pressures above 250 bar, necessitating a shift to volume control via a variable‑volume control valve (VCV). These findings indicate that methanol’s lower density and higher vapor pressure increase the risk of cavitation in high‑pressure components, and that operating pressures must be reduced to maintain reliability.

The injector itself was found to be incompatible with methanol at the low pressures it is designed for; the standard diesel injector could not be operated at the reduced pressure regime required for methanol, leading to injector cavitation and failure. Consequently, the project recommends the development of new injector designs optimized for methanol’s properties. The study also identified a combined corrosion‑cavitation effect that may explain the limited high‑pressure tolerance of the existing diesel components. Further detailed investigations into this phenomenon are suggested to enable safe operation at higher pressures.

From a collaboration perspective, TEC4FUELS led the experimental work and data analysis, while OWI GmbH provided the test infrastructure and technical support. The project also involved Liebherr, which evaluated the compatibility of diesel components with methanol and contributed to the interpretation of failure modes. The research was conducted over a period that included endurance tests up to 200 h, with a total of fifteen distinct test scenarios (S1V1–S1V15 and S2V1–S2V5). The outcomes of these tests are summarized in a comprehensive matrix that documents operating parameters, run times, and failure reasons.

In addition to the technical assessment, the project addressed standardization issues. The “AP E” work package compared existing methanol standards worldwide and identified gaps in quality requirements for automotive use. The goal is to establish normative guidelines that ensure safe and efficient deployment of methanol in the transport sector, thereby reducing CO₂ emissions by leveraging renewable sources such as biogas or power‑to‑fuel processes. Overall, the TEC4FUELS project demonstrates that methanol can be used in diesel systems with appropriate component modifications and operating‑pressure adjustments, while highlighting the need for further research into injector design and corrosion mitigation.