Opposed-piston internal combustion engine

An opposed-piston internal combustion engine that is an internal combustion engine comprising an intake compression cylinder and an expansion exhaust cylinder, in an opposed-piston crank mechanism, and comprising a rotating perforated columnar valve and an ignition combustion chamber between the intake compression cylinder and the expansion exhaust cylinder, in which a piston takes in and compresses air at a predetermined timing from an intake valve located on a side surface of the intake compression cylinder, the rotating perforated columnar valve rotates at half a number of revolutions of a crankshaft, the rotating perforated columnar valve has a straight-line introduction hole for passing compressed air, the introduction hole introduces air compressed in the intake compression cylinder into the ignition combustion chamber at a predetermined timing, the compressed air introduced into the ignition combustion chamber by the introduction hole is mixed with a fuel supplied by a fuel injection device installed in the ignition combustion chamber, and starts combustion by ignition of a spark plug installed in the ignition combustion chamber, the ignition combustion chamber has a combustion gas ejection hole for introducing combustion gas generated by the combustion into the expansion exhaust cylinder, the combustion gas is supplied to the expansion exhaust cylinder from the combustion gas ejection hole and expands, the expansion exhaust cylinder has a multi-stage fuel injection device that injects fuel into the combustion gas, the multi-stage fuel injection device increases combustion gas pressure by injecting the fuel into the combustion gas in the expansion exhaust cylinder at a predetermined timing, gas expansion energy of the combustion is converted into power by a piston crank mechanism, and gas after combustion is discharged at a predetermined timing as exhaust gas from an exhaust valve located on a side surface of the expansion exhaust cylinder, wherein respective steps of intake, compression, combustion expansion, and exhaust are completed by one rotation of cranks, pistons are connected to connecting rods, and connecting rods that are symmetrically arranged with respect to the connecting rods, and arranged to face each other in the intake compression cylinder, pistons are connected to the connecting rods, and the connecting rods that are symmetrically arranged with respect to the connecting rods, and arranged to face each other in the expansion exhaust cylinder, the respective connecting rods are connected to the cranks that are symmetrically arranged, and cranks that are arranged to face the cranks, the cranks move in conjunction with each other by gears that are directly attached to the cranks respectively, and gears that have output shafts and are symmetrically arranged, and the gears having the output shafts have rotating shafts that drive the rotating perforated columnar valve in an engine inner side, and transmit rotational power to the rotating perforated columnar valve by the gears.