a massive inlet valve we can vary the inlet air charge while maintaining a constant compression ratio fig3 shows an exploded isometric view of the preferred embodiment the dominate feature of the engine is the cylinder housing assembly 32 the engine will have at least one cylinder housing assembly the cylinder housing assembly has two opposed cylinders each cylinder surrounds a double piston 34 the double pistons join together and rotatably join the double pistons to the planetary crankpin drive mechanism 36 each cylinder housing assembly will have one centrally located planetary crankpin drive mechanisms the reciprocating motion of the pistons is controlled by the crankpin drive mechanism power is extracted from the engine or applied to the engine for starting by the crankpin drive mechanism each cylinder is capped with an inlet valve assembly 38 alternate embodiments include multiple cylinder housing assemblies if the housings are in line the inlet valve assembly can be extended to operate multiple cylinders likewise the planetary gear assemblies can be coupled dynamic oscillations can be mitigated if the reciprocating masses move in opposite directions 180 u00b0 out of phase if the cylinder housing assemblies are not in line the dynamic performance can be altered to improve smoothness of torque another alternate embodiment could employ eccentric bearings to support the crankpin drive mechanism instead of planetary gears fig4 a shows an isometric view of the cylinder housing assembly the main part of the cylinder housing.