Patent ID: 7992529

Claim:
An internal combustion engine, comprising: an upper link connected via a piston pin to a piston that reciprocates within a cylinder; a lower link attached to a crank pin of a crankshaft to be free to rotate and connected to the upper link via an upper pin; and a control link which is connected to the lower link via a control pin and oscillates about an oscillation central shaft, wherein a following equation is established when the piston is at bottom dead center cos(θ l +α)<cos(θ l +π) where: θ l is a lower link attitude angle formed by a line connecting the control pin and the crank pin and a line perpendicular to the upper link and passing through the crank pin; and α is a lower link aperture angle formed by the line connecting the control pin and the crank pin and a line connecting the crank pin and the upper pin.