Combination internal combustion and steam engine

A compound internal combustion engine assembly comprising:

• a first combustion chamber;
• a second combustion chamber;
• a steam chamber having a work-output device mounted for movement therein;
• a first passageway extending between said first combustion chamber and said steam chamber;
• a second passageway extending between said second combustion chamber and said steam chamber;
• means for operating said first and second combustion chambers in a 360 degree out-of-phase, four-stroke combustion cycle;
• valve means for opening said first passageway during an exhaust stroke of said first combustion chamber, opening said second passageway during an exhaust stroke of said second combustion chamber, and closing said first and second passageways during all other strokes of respective ones of said first and second combustion chambers;
• and
• water injection means for injecting water into hot exhaust gases in said first and second combustion chambers during respective openings of said first and second passageways to create pressurized, super-heated steam in said steam chamber and initiate a steam work-expansion process in which said pressurized, super-heated steam performs work on said work-output devices as said pressurized, super-heated steam expands in said steam chamber, whereby one of said steam work-expansion processes occurs for each combustion cycle of said first and second combustion chambers.