F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
F02B75/00—Other engines
F02B75/28—Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders
F02B75/287—Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders with several pistons positioned in one cylinder one behind the other