FIELD: engine engineering. SUBSTANCE: method includes injection of fuel-air mixture and vapor in a cylinder, ignition of charge, by-passing at least smaller part of gases in expanding cylinder, discharging gases from cylinders through separated passages and subsequent expanding of gases out of cylinders, condensation of vapor containing in gases of the main cylinder, and sucking off non-condensed gases. In so doing the non-condensed gases is burnt out in the engine. The internal combustion engine has expanding cylinder whereto the main cylinder is connected, valves for gas distributing in the cylinders, nozzle for supplying vapor and spark plug provided within the main cylinder, ejector provided in outlet passage of the expanding cylinder whose active nozzle is in communication with additional burning chamber, and passive nozzle with the first stage of expanding of the gas turbine. The resulting nozzle is in communication with the second expanding stage. EFFECT: enhance efficiency. 3 cl, 1 dwg
