FIELD: power mechanical engineering. SUBSTANCE: method comprises supplying fuel- air mixture to the major cylinder, compression of the mixture, igniting the mixture in the major cylinder, by- passing a portion of combustion products through a by- pass to the expanding cylinder, discharging exhaust gases from both of the cylinders, delivering water to heat exchangers, heating and evaporating water, and supplying the vapor to the major cylinder to the zone opposite to the by-passing valve. Exhaust gases are discharged from the major cylinder, additionally expanded, and cooled up to a temperature of water condensation, the non-condensed gases being ejected. The cylinder bank and the cylinder head are used as heat exchangers. The engine comprises cylinder bank, major and expanding cylinders mounted inside the cylinder bank and connected to the valve through a by-pass, and bank head with passage ways for supplying and discharging mixture and exhaust gases, respectively. The engine also has turbine, cooler, ejector, and heat exchanger and heat exchanger-evaporator connected in series. The heat exchanger-evaporator is connected with the outlet passageway of the expanding cylinder. The heat exchanger-vapor superheater is provided with a chamber for combustion of fuel-air mixture and connected with the outlet passageway of the expanding cylinder. Upstream of the heat exchangers and heat exchanger-evaporator are pumps. EFFECT: enhanced efficiency. 5 cl, 2 dwg
