Analysis of Mixture Formation and Combustion in H2 Engines for Passenger Cars and Light Commercial Vehicles

Hydrogen is on its way to become an important energy carrier of the future. It will contribute to well-to-wheel and life cycle CO2 neutral on-road mobility solutions including EU targets for CO2 neutrality towards 2050. Following a technology neutral approach, the hydrogen engine powertrain can be an important part of potential solutions. The paper focuses on relevant powertrain topologies for applications in light commercial vehicles (LCV) and passenger cars (PC) utilizing future hydrogen engines. The requirements and challenges on related components as well as subsystems like fuel injectors and exhaust gas treatment are discussed. For the analysis of the H2 mixture formation, optical measurements in a pressure chamber visualizing the injected jet are used for basic understanding of the process. Further, 3D-CFD in-cylinder flow simulations are introduced for optimizing the H2 mixture preparation. The assessment of the engine efficiency based on thermodynamic loss analysis is illustrated using the cases of port fuel and direct injection. The requirements of the exhaust gas treatment concepts for LCV/PC powertrains utilizing H2 engines are discussed, and possible configurations are shown. The results demonstrate feasibility and attractive characteristics of hydrogen engine- based powertrains for future on-road mobility.