Liebherr’s Approach to Hydrogen Fuel Injection Systems

Liebherr develops hydrogen fuel injection system solutions to be used in on- and off-highway hydrogen combustions engines. Heavy-duty off-highway applications have partly different requirements compared to on-highway applications. Robustness against dust, dirt & vibrations and other harsh environmental conditions must be given. Additionally higher peak power demand and more dynamic load cycles increase the requirements on the transient performance of the engine. To meet these requirements, Liebherr has developed a complete hydrogen injection system that includes all the components needed for pressure regulation and fuel dosing. Throughout the development, real load cycles of heavy-duty mobile machinery have been considered to properly design the system and its components. This paper will provide detailed insights on the layout, design and functionality of the hydrogen injection system. In particular, the dynamic pressure regulation by means of a gas metering valve is shown and how this approach enables diesel-like transient engine behavior. Furthermore, first test results on the system performance are provided. Additionally an overview on the common platform approach to the Liebherr portfolio of hydrogen fuel injectors for port fuel injection (PFI) and direct injection (DI) incl. actual test results will be given. Liebherr’s approach to hydrogen fuel injection systems are not only limited to heavy duty commercial engines. Also components for large engines are considered in the overall platform approach.