Patent ID: 6779495
Filing Date: 2004-08-24
Classification: F02B,F02F

Abstract:
A variable compression ratio engine wherein one end of a connecting rod is connected to a piston via a piston pin and the other end of the connecting rod is swingably connected to one end of a sub-rod that is in sliding contact with half of a periphery of a crankpin of a crankshaft, a crank cap in sliding contact with the other half of the periphery of the crankpin is secured to the sub-rod, and one end of a control rod is swingably connected to the other end of the sub-rod,wherein the other end of the control rod is swingably connected to a support shaft provided at a position eccentric relative to a rotating shaft that is swingably and axially supported in an engine main body via a one-way clutch, wherein an actuator is supported in the engine main body, the actuator is a diaphragm actuator in which a peripheral edge of a diaphragm is sandwiched by a casing, wherein respective opposite sides of the diaphragm face a negative pressure chamber in communication with an intake passage within a carburetor mounted on the engine main body and an atmospheric pressure chamber that is open to the atmosphere, wherein a restricting projection is provided on the rotating shaft at a location in a circumferential direction on the rotating shaft and projects outward in a radial direction, wherein a shaft member is provided in the engine main body so that an axis of the shaft member is perpendicular relative to the rotating shaft, wherein a rocker member is mounted on the shaft member and rocks around the axis of the shaft member, the rocker member having a pair of engagement portions which have phases displaced from each other and which engage the restricting projection, the rocker member being spring-biased in a direction in which one of the engagement portions engages the restricting projection, and wherein the actuator is connected to the rocker member so that the rocker member swings in a direction opposite to the spring-bias direction in response to an increase in a negative pressure of the negative pressure chamber.