F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
F01B3/0002—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
F01B3/0005—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders having two or more sets of cylinders or pistons