Authors

J. Steinmill, Schaeffler Engineering, Werdohl; J. Leberwurst, S. Sulzer, J. Broz, O. Weber, Schaeffler AG, Herzogenaurach

Year

2026

Print Info

Production/Publication ÖVK

Summary

Global regulations for CO₂‑neutral commercial vehicles are increasingly shifting toward technology‑open solutions. In addition to battery‑electric and fuel‑cell systems, hydrogen internal combustion engines (H₂‑ICE) are now also being recognized as zero‑emission options, as they emit virtually no CO₂. This trend strengthens interest in robust, cost‑effective, and easily scalable propulsion technologies, especially for heavy‑duty applications.
However, hydrogen combustion engines face the challenge of achieving sufficiently homogeneous mixture formation under restrictive injection conditions. But a good homogeneity is essential for minimizing NOx emissions. Conventional direct injectors reach their limits here.
The newly developed Dual Mode Injector provides an innovative solution: by switching between Jet flow and Coandă flow, controlled via injector pressure, cylinder pressure, and needle lift. The injector can adapt the spray pattern flexibly to the operating point. CFD analyses and Schlieren imaging demonstrate significantly improved air entrainment, stronger velocity gradients, and a less heterogenous air/fuel distribution.
Engine tests confirm these findings. Compared with conventional direct injectors, the Dual Mode Injector closes the gap to the PFI NOx results by approximately 50%, without suffering from PFI’s performance limitations. At the same time, engine efficiency remains high or even increases with later injection timings. This demonstrates the strong potential of advanced hydrogen direct‑injection technologies to make hydrogen combustion engines a practical, cost‑efficient, and climate‑neutral solution for heavy‑duty commercial vehicles. In addition, the results are transferable to natural gas operation.

ISBN

978-3-9504969-5-6

DOI

https://doi.org/10.62626/4xez-a5sm Copy link

Order Members Login