Hydrogen Combustion Concepts: Comparison of Port Fuel Injection with Spark Ignition and High Pressure Direct Injection (HPDI TM) – Power Density, Efficiency, and Emissions

Authors

Dr. X. Seykens, Dr. E. Doosje, Dr. C. Bekdemir, Dipl.-Ing. (FH) P. van Gompel, TNO, Helmond:

Year

2023

Print Info

Production/Publication ÖVK

Summary

The hydrogen combustion engine (H2-ICE) is an attractive solution to significantly contribute to the achievement of CO2 reduction targets set in Europe’s Green Deal. This is especially relevant for applications that are challenging to electrify, such as heavy equipment (e.g. long haulage trucks and off-road machinery including inland shipping). Uptake of H2-ICE requires a competitive performance compared to (less sustainable) alternatives. The chosen combustion concept at the heart of H2-ICE plays a distinct role in chances for success. In this paper, an overview of the main results from recent experimental hydrogen combustion engine research at TNO are presented. An important aspect within this research is the quantification of main trade-offs for different hydrogen combustion concepts on the same heavy-duty single cylinder engine platform. The key performance indicators and their limiting factors for both lean burn port fuel injection (PFI SI) as well as High Pressure Direct Injection (HPDITM) combustion are quantified in this experimental work. Presented work considers fixed speed operation without the use of exhaust gas recirculation, primarily with stationary power generation in mind. The PFI SI concept is shown to have high potential for low NOx operation at medium to high load. The available load range for low NOx is mainly limited by the occurrence of engine knock and available boost pressure. High loads in excess of 24 bar have been achieved through the use of water injection and boost pressures above 4 barA. Shown load range potential comes at the cost of increased engine-out NOx. The HPDI combustion concept clearly outperforms the PFI SI concept regarding maximum efficiency potential with observed net indicated efficiencies that are > ~7%-point higher than for the PFI SI concept. High engine loads can be achieved with conventional boost pressures and base CI engine combustion chamber hardware (i.e. compression ratio and piston shape). NOx emissions are, however, significantly higher and require the use of exhaust gas aftertreatment.

ISBN

978-3-9504969-2-5