Experimental analysis of boost limits in a hydrogen fueled PFI internal combustion engine

Abstract

In recent years we have witnessed a renewed interest in the use of hydrogen as a fuel for the land transportation sector, not only for the decarbonisation of the propulsion system but also, above all, as an energy vector for accumulating excess energy deriving from the use of intermittent renewable sources such as wind and photovoltaics.The present study shows the results of an ongoing research aimed at fine-tuning ready-to-market strategies for the use of hydrogen in ICEs. Starting from a turbocharged engine fueled by natural gas and utilized on light commercial vehicles, a low-cost indirect hydrogen injection system (PFI) was implemented, combined with appropriate injection strategies and boost pressure analysis, this last assuming a fundamental aspect in recovering engine performance that inevitably deteriorates with the use of diluted mixtures.It is found that the adoption of an air/hydrogen lambda value (λ) ≈ 2.5 allows the utilization of high boost ratios without knocking and backfire and with the possibility of reaching performance similar to the original natural gas fueled engine, with a higher efficiency (> 39 %) and with low NOx emissions (< 200 ppm).