FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: proposed two-stroke internal combustion engine has crank gear and several operating cylinder 11, 12 with bottoms and divided by pistons into lower and upper chambers. Lower chambers of cylinders are used mainly for compressing working mixture, and upper chambers 41, 42 serve for combusting the mixture. Engine has accumulating cylinders which can be connected with chambers 28, particularly, with operating cylinders of engine and processing chambers. Accumulating cylinders are made so that each adjacent chamber has at least one overlapped intake port 33 through which fuel-air mixture can get, for instance, from accumulating cylinder into chamber. At least one overlapped exhaust port 31 is provided through which mixture can get from chamber into accumulating cylinder 28. Fuel-air mixture gets into accumulating space of cylinder 28 from lower chambers 11, 12, 41, 42 of operating cylinders. If necessary, fuel-air mixture can be delivered from accumulating space into upper chambers of operating cylinders, where mixture is combusted. Mixture from lower chambers of operating cylinders can be directed into definite compartments of accumulating cylinder where it is delivered for processing into processing chamber. After processing, mixture is returned into the same compartments of accumulating cylinder and then is fed from these compartments into upper chambers of operating cylinders where it is combusted. Provision of accumulating cylinder makes it possible to prevent losses at scavenging, as fuel-air mixture is not delivered into cylinder when piston passes its bottom dead center and is delivered into cylinder during entire compression stroke when exhaust port is closes. EFFECT: enhanced operation of engine. 17 cl, 2 dwg
