The engine is composed of crank and rod mechanism and valve mechanism two institutions, as well as cooling, lubrication, ignition, fuel supply, start the system composed of five systems. The main components are cylinder block, cylinder head, piston, piston pin, connecting rod, crankshaft, flywheel and so on. The working chamber of the reciprocating piston internal combustion engine is called a cylinder, and the inner surface of the cylinder is cylindrical. The reciprocating piston in the cylinder is hinged through the piston pin and the other end of the connecting rod. The other end of the connecting rod is connected with the crankshaft. The crankshaft is supported by the bearing on the cylinder block and can be rotated in the bearing to form the crank link mechanism. When the piston is reciprocating in the cylinder, the connecting rod drives the crankshaft to rotate. On the other hand, when the crankshaft rotates, the connecting rod journal is circumferentially moved in the crankcase and moves the piston up and down through the connecting rod. Crankshaft every turn a week, the piston, the next run once, the cylinder volume in the constant from small to large, and then by the big smaller, so endless cycle. The top of the cylinder is closed with a cylinder head. The cylinder head is equipped with an intake valve and an exhaust valve. Through the inlet and exhaust valve opening and closing to achieve the cylinder into the exhaust and exhaust to the cylinder. The opening and closing of the exhaust valve is driven by the camshaft. The camshaft is driven by the crankshaft through the toothed belt or gear.