Innovative H2-DI Injector with Cycle-Specific Injection Patterns for Next-Generation Light Aircraft Propulsion

Abstract

To meet the CO₂ reduction targets in the transportation sector, the adoption of sustainable fuels is indispensable, with hydrogen emerging as an especially promising energy carrier. In particular, direct hydrogen injection demonstrates distinct advantages over port fuel injection, including higher power density and a diminished risk of irregular combustion phenomena. However, mixture formation in late H₂ direct injection remains one of the principal challenges in this context. Current state-of-the-art hydrogen direct injection technology predominantly relies on fixed jet shapes, which are employed in conjunction with in-cylinder flow and wall-guided strategies. The innovative Schaeffler Dual-Mode Nozzle introduces, for the first time, a targeted utilization of two differentiated spray configurations - Coandă and Jet - and their intermediate forms, thus enabling dynamic adaptation of mixture formation to different operating conditions. This approach offers considerable potential for efficiency and cost optimization, particularly in first-generation H₂ engines that share numerous components with diesel engines, thereby facilitating a pragmatic entry into hydrogen-based mobility. This paper outlines the advantages and functionalities of the “Dual Mode Nozzle”. Additionally, experimental investigations were conducted at the Institute for Powertrains and Automotive Technology (IFA) at TU Wien to analyze emissions, efficiency and combustion parameters of the dual mode H₂ direct injection system.