Technology Status of Hydrogen Road Vehicles

y Furahama et al. (1991) for high-pressure only injection where, even with eight jets, ignition starts on one
jet and proceeds to adjacent ones in turn; it should also avoid the increased NO x at low speed with internal as
compared to external mixture formation. The external mixture formation was expected to speed up the flame
diffusion, and in fact, using the optical research engine with Schlieren photography, optimum combustion and
minimum NO x resulted for the entire speed and load range. What is not clear from this dual approach is
whether the combined advantages of two injections outweigh the combined disadvantages.
Koyanagi (1993) reported some optimization studies on high-pressure injector variables that affect mixing and
combustion: injection pressure, nozzle geometry etc.
Finally, the Japanese team has unveiled Musashi-9, a LH 2 refrigerated and fueled van included in Table 1 as
item 15. The original six-cylinder 6-liter engine was modified by replacing the diesel injectors with nine-hole
high-pressure LH 2 ones, installing a spark plug, bringing the compression ratio to 13:1 and fitting a piston with
cavity of 0.76 squish ratio. The results were good, in particular the NO x was reduced to very low values (about
half the 13-mode target) by slight injection retardation, hot-EGR of 10%-20% with air/fuel ratio of 1.3-1.5
(Yamane et al. 1994; Hiruma et al. 1995).
Other groups are also attempting to adapt the difficult high-pressure LH 2 injection to ICEs. But performance
and emissions data are not available on these projects so they cannot be further discussed here.
The 11th WHEC includes several papers of interest to this appendix, and relevant points are included in the
main text. In particular, the following papers can be quoted and are summarized in Appendix 4: Fulton
(1996), Provenzano (1996), Peschka (1996), Naber (1996), Digeser (1996), Kondo (1996), Valdimarsson
(1996), Meier (1996), Brown (1996), Knorr (1996).
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