How Efficient are Hydrogen-Fueled Internal Combustion Engines?
Pp. 275-311 (37)
S. Verhelst, R. Sierens and T. Wallner
Hydrogen has long been recognized as an energy carrier for the
transportation sector with a number of important advantages compared to the currently
used fossil fuels. It can be produced from a variety of (renewable) energy sources and it
can produce energy in an efficient and clean way. For powering vehicles, hydrogen can
be used in two ways, either in a fuel cell (FC) producing electricity, or in an internal
combustion engine (ICE) producing mechanical power. Converting an ICE to hydrogen
operation is relatively straightforward and is interesting as it offers a bi-fuel possibility.
What is less known is that a hydrogen-fueled ICE (H2ICE) has a high efficiency
potential, leading to a smaller gap in efficiency compared to a hydrogen-fueled FC than
commonly assumed. This chapter describes the physical and chemical properties of
hydrogen that theoretically allow a high engine efficiency, and presents experimental
confirmation of these theoretical considerations. Published efficiency figures obtained
by engine testing are reviewed and recent work on both port fuel injection (PFI) as
direct injection (DI) H2ICEs is discussed. Finally, an outlook is given on the potential
for further increases in efficiency.
Hydrogen, internal combustion engines, spark ignition, fuel, bi-fuel,
NOx, combustion, emissions, efficiency, transportation, vehicles, injection,
knock, mixture formation, injection strategies, injection strategies, power density.
Department of Flow, Heat and Combustion Mechanics Ghent University, Belgium