Technology Status of Hydrogen Road Vehicles

Pizak, V. et al., “Investigations of the Kinetics and Catalysis of the Iron/Steam-Magnetitie/Hydrogen
System in low temperature regime with regard of its use to produce and store hydrogen,” Center for
Solar Energy and Hydrogen Research, Ulm, Germany, pp. 1175-1183.
This poster presentation examines an old method for H 2 production—reacting steam with red-hot sponge ironfor
suitability for on-board use, especially using sponge iron from the direct reduction of iron process.
After some fundamental work on the kinetics of the reaction, the main result seems to be that a very large and
stabilized surface area of sponge iron is needed at temperatures lower than 300ºC. The method is, however,
practicable for hydrogen generation from sponge iron (which in turn could have been produced by H 2
reduction of the ore), but best introduced in heavy transport systems such as locomotives or submarines.
TOPIC 4: Technologies of Hydrogen Utilization
Scott, D.S., et al., “Harvesting Thermomechanical Energy from LH 2: Transportation Applications,”
University of Victoria, British Columbia, Canada, pp. 1449-1452.
The authors point out that the 10% thermomechanical energy in LH 2 should not be wasted, concentrating only
on its 90% chemical energy. By comparison, gasoline has 0% thermomechanical energy and steam has 100%.
An example of how to harness this 10% in LH 2 would be to use it as the heat sink in a cryogenic heat engine.
There are other possibilities that the designer should stay alert to.
Peschka, W., “Hydrogen the Future Cryofuel Fuel in Internal Combustion Engines,” German Aerospace
Research Establishment, Stuttgart, Germany, pp. 1453-1481.
This comprehensive review of the successive improvements in ICE performance with LH 2 fuel takes as a
starting point the order-of-magnitude advantage that the ICE has over the FC for specific power (kW/kg), with
today’s technology or even with advanced technology.
After reviewing the problems with external mixture formation, and internal mixture formation with early-start
injection, he concludes that latter not much better than former, and that late-start injection (~ 5 o BTDC),
although it resolves most problems, has only about 5 ms at 5,000 rpm for injection, mixing, ignition, and
combustion. This means that 15–20 Mpa LH 2 injectors are needed to inject much increased gaseous fuel
volumes (in small and medium vehicles, cryogenic H 2 is always gas in combustion chamber) in the 2-3 ms
available.
He therefore feels that the optimum solution is a hybrid one: early-start injection of 0.4-0.5 Mpa LH 2 into a
lean mix, ignition at ~5 o BTDC with no pre-ignition or NO x; then cryogenic H 2 injected at 20 MPa into flame
front at ~5 o BTDC giving turbulence and mixing. This hybrid allows very low NO x, and gives similar engine
performance (power and torque) as conventional fuels.
He claims that fuel conditioning systems for LH 2/ICE is much cheaper than low-cost FC.
Naber, J.D.; D.L. Siebers, “Hydrogen Combustion under Diesel Engine Conditions,” Sandia National
Laboratories, California, USA, pp. 1503-1512.
There are potential advantages in efficiency, power density, and safety in hydrogen engines running under
diesel direct-injection conditions, compared to premixed, spark-ignited conditions.
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