VARIABLE COMPRESSION RATIO APPARATUS

A variable compression ratio apparatus is provided. The apparatus includes a connecting rod, a small end forming an aperture to be rotatably connected with a piston pin moving together with a piston, a larger end rotatably connected with a crankpin eccentrically arranged with respect to the crankshaft. An acting oil passage allows hydraulic pressure to be supplied from the larger end to the small end. An eccentric cam is concentrically arranged and rotatably disposed in the aperture of the small end. The piston pin is inserted thereinto and rotatably connected therewith. A latching pin is disposed in the small end to generate a reciprocal rectilinear motion in a direction of a rotation axis of the small end and selectively latches the small end with the eccentric cam in one of at least two relative positions between the small end and the eccentric cam by hydraulic pressure.