Heat engine and heat pump

An internal combustion engine comprising:

• a compression chamber to contain gas to be compressed;
• a first piston to compress said gas by movement of the piston in the compression chamber;
• driving means arranged to drive said first piston into the compression chamber to compress said gas;
• spray forming means arranged to spray liquid directly into said compression chamber to cool the gas on compression therein, said spray forming means being arranged to deliver a sufficient quantity of liquid into said compression chamber such that the heat of compression is transferred to the spray liquid by convection and absorbed into the spray liquid substantially as sensible heat, the spray liquid remaining substantially in the liquid state to the end of compression in said compression chamber;
• separator means arranged to separate the spray liquid from the compressed gas/spray liquid mixture leaving said compression chamber;
• an expansion chamber;
• a second piston to allow gas to expand by movement of the second piston out of the expansion chamber;
• transmission means comprising a solid member operatively coupled to said second piston to permit power from the engine to be drawn;
• first means arranged to feed from said separator means to said expansion chamber compressed gas for combustion in said expansion chamber;
• and
• second means to deliver combustible fuel into said expansion chamber, whereby combustion thereof in said expansion chamber with said compressed gas drives said second piston.