I seem to remember that they had a Rotory engine running on Hydrogen in some MX-5 demonstrator.
Apparently a Rotory engine is good with hydrogen, due to the intake and combustion taking place in different areas it has less problems with heat.

I might have imagined it though... =)

Jazz
(List 112, Mk2 12 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)
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Jazz (List 112, Mk2 42 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)