Abstract: An internal combustion engine in which a rotor or turbine is driven by the exhaust gases of a pair of interconnected double-acting pistons. The double-acting pistons are interconnected by a pinion gear and are internally constructed to have an inner piston slidably reciprocating within a chamber defined within an outer piston. The purpose of the inner piston is to feed additional fuel into the main combustion chamber in a controlled manner. Exhaust gases are collected and washed before being exhausted to the atmosphere or recycled within the engine.