CPC Subgroup
F01B 21/02 the machines or engines being all of reciprocating-piston type
Full Title
Combinations of two or more machines or engines (F01B23/00 takes precedence) > the machines or engines being all of reciprocating-piston type
F01B 21/02 Combinations of two or more machines or engines (F01B23/00 takes precedence) > the machines or engines being all of reciprocating-piston type