Possible Clues:

• German engineer/inventor
• Inventor of a compression-ignition engine
• Tank filler
• Gas-pump selection
• Rudolf __ , French-born German engine inventor, d.1913
• Fuel driver smells -- what are the odds?
• Passes on the foreign fuel
• Breaks down on the foreign fuel
• Motor fashioned from cube with odd bits of steel
• Many a truck engine