in an internal combustion engine with a reciprocating movement which uses gasoline , diesel fuel or other fuels to generate forces when fuels attain explosive combustion , the piston is pushed in the inner cylinder . the motion of the piston with the reciprocating movement is transferred to a crank shaft having rotation motion , or the rotation motion of the crank shaft is transferred to the piston having straight motion . by such transfer , in order to use in compressed feed for fluids , when the connecting rod is provided with a universal joint type and a ball joint type , although the relative position errors and right angle are staggered within a given range , abnormal friction , noises and vibrations never take place . accordingly , pollutions such as noise , vibration and noxious exhaust gases are dramatically reduced , fuels are surprisingly and significantly saved , and the life of the machine is doubly increased . further , the piston is divided into a crown part and a skirt part , and the crown part is used with a piston ring in a conventional way . however , the skirt part is attached to a metal roller mounted on a metal bracket , or a metal plate or spring , and the piston is provided with an expansion property . accordingly , the gap or clearance between the cylinder and the piston is completely removed , and maximum smoothing motion takes place when the piston is moved up and down . by such smoothing action of the piston , a state without tilt and slap is realized .