Abstract: A balanced five cycle internal combustion engine having first and second inlet and outlet annular cams configured to move first and second inlet and outlet pistons respectively within associated cylinders through successive five cycle repeating movements each of which includes (1) a power cycle, (2) an exhaust cycle, (3) a transfer cycle, (4) an intake cycle, and (5) a compression cycle. The movements of each first inlet piston and an associated first inlet cam follower being accompanied by an equal and opposite movement of a second inlet piston and an associated second inlet cam follower so that all movements of the first and second inlet pistons and the associated first and second inlet cam followers thereof are dynamically balanced.

Abstract: An internal combustion engine of the opposed piston type valved by the passage of the pistons beyond inlet and outlet ports at opposite ends of the cylinders. The motion transmitting mechanisms for the opposed pistons are operable to move the opposed pistons within each cylinder through a successive three cycle repeating movement which includes (1) an operative power cycle, (2) a gas exchange cycle, and (3) an operative compression cycle.