A reciprocating compressor. A hollow cylinder tube contains a piston assembly having two pistons connected by a piston rod. At each end of the cylinder tube is an outer chamber between an end plate and an outer end of the proximate piston. These two outer chambers and the outer ends of the pistons define a power cylinder at each end of the cylinder tube. In the mid-portion of the cylinder tube, a center divider is situated between the pistons and has an aperture that allows the piston rod to reciprocate through it. The two inner chambers formed thereby and the inner ends of the pistons define two compression cylinders in the mid-portion of the cylinder tube. The two compression chambers share a suction manifold and a discharge manifold, but have independently operating suction and discharge valves.

An engine includes a cylinder block with a fixed trunnion and a cylinder head pivotably attached to the trunnion. The engine has a charge piston and power piston operating in cylinders attached to the cylinder head. Cylinder head valving controls an airflow from the trunnion interior into a charge piston volume during a charge piston intake stroke and restricts an opposite airflow during a charge piston compression stroke. Chamber valving allows an airflow into a chamber within the charge piston during a compression stroke and captures the air in the chamber during an intake stroke. At Bottom Dead Center (BDC), passages in the charge piston, power piston, and their cylinders form a flow path between the chamber and power piston volume. A throttle body controls air intake into the trunnion, and an ignition device in the cylinder head ignites fuel and air in the power piston cylinder.

An engine includes a cylinder block with a fixed trunnion and a cylinder head pivotably attached to the trunnion. The engine has a charge piston and power piston operating in cylinders attached to the cylinder head. Cylinder head valving controls an airflow from the trunnion interior into a charge piston volume during a charge piston intake stroke and restricts an opposite airflow during a charge piston compression stroke. Chamber valving allows an airflow into a chamber within the charge piston during a compression stroke and captures the air in the chamber during an intake stroke. At Bottom Dead Center (BDC), passages in the charge piston, power piston, and their cylinders form a flow path between the chamber and power piston volume. A throttle body controls air intake into the trunnion, and an ignition device in the cylinder head ignites fuel and air in the power piston cylinder.