The unique properties of hydrogen create certain
challenges, such as combustion anomalies, but also open
up the potential to increase the power output by more than15% compared to conventional gasoline engines. Further,
the wide flammability limits and high flame speeds even
under lean conditions enable the use of highly efficient
lean-burn engine load control strategies. At this point,
prototype and demonstration vehicles, such as the Ford
Hydrogen Shuttle bus or the BMW Hydrogen 7 take some
advantage of the unique properties of hydrogen while
demonstrating the (near-) zero emissions potential. In a
research environment, advanced mixture formation concepts
such as cryogenic injection or direct injection, that
more fully exploit the possibilities due to the specific
properties of hydrogen, have been proven to achieve
engine efficiencies in excess of 45% which exceed those
currently achieved with gasoline or diesel.