Internal combustion engine with asymmetric port timing

An internal combustion engine comprising:

• a crankshaft having a crankpin to which each piston of an opposed pair of pistons is connected and by which the pistons reciprocate in a respective one of axially inline cylinders;
• a crosshead having opposite ends on which a respective one of the pistons is mounted;
• and a coupling between the crosshead and the crankpin to cause the pistons to oscillate circumferentially as the pistons reciprocate, each piston having a crown that co-operates with respective inlet and outlet ports of the inline cylinders, the crown including a segmented skirt projecting beyond the crown, the segmented skirt having two arcuate, circumferentially spaced skirts at opposite sides of the crown such that first opposing ends of the respective skirts form a first opening to define an inlet and second opposing ends of the respective skirts form a second opening to define an outlet, the coupling between the crosshead and the crankpin including a connector that is fitted on, and able to move along, the crankpin, the coupling between the crosshead and the crankpin being reversibly moveable along the crankpin, the coupling to engage the crosshead so as to be reversibly rotatable relative to the crosshead along an axis that is parallel to and laterally offset from a reciprocating axis along which the pistons reciprocate, the crosshead and the coupling to impart a partial rotary motion to the pistons as the pistons reciprocate in the inline cylinders, overall motion of the pistons to produce an elliptical path for each piston in the respective ones of the inline cylinders that, in combination with the crowns, enables asymmetric port timing.