Patent ID: 6843212
Filing Date: 2005-01-18
Classification: F02B

Abstract:
1. An engine with a variable compression ratio, comprising a connecting rod connected at one end to a piston through a piston pin, a first arm turnably connected at one end to the other end of said connecting rod and at the other end to a crankshaft through a crankpin, a second arm integrally connected at one end to the other end of said first arm, a control rod turnably connected at one end to the other end of said second arm, and a support shaft for supporting the other end of said control rod for turning movement, the position of said support shaft being displaceable within an x-y plane constituted by an x-axis extending through an axis of said crankshaft along a cylinder axis and a y-axis extending through the axis of said crankshaft in a direction perpendicular to said x-axis, wherein when a length of said connecting rod is represented by L wherein φ dφ φ φ C=Ypiv−R sin θ D=Xpiv−R cos θ dφ and the crank angles θ at a top dead center and a bottom dead center of said piston pin at the time when said support shaft is in a first position are determined by introducing L 1 , to L 4 , δ and R each set at any value into said equation; a displacement Vhpiv 0 and a compression ratio εpiv 0 at the time when said support shaft is in the first position and a displacement Vhpiv 1 and a compression ratio εpiv 1 at the time when said support shaft is in a second position displaced from the first position are determined from the following equation representing a level X of said piston pin at both said crank angles θ: and the length L 1 , of said second arm, the length L 2 of said first arm, the length L 3 of said control rod, the length L 4 of said connecting rod, the amount δ of offsetting of the cylinder axis from the axis of said crankshaft in the direction of the y-axis and the angle α formed by said first and second arms are determined, so that the following relations are satisfied: