Patent ID: 8302568

Claim:
A variable compression ratio apparatus for a vehicle engine that is mounted at the engine receiving combustion force of an air-fuel mixture from a piston and rotating a crankshaft mounted between upper and lower cylinder blocks, and that changes compression ratio of the air-fuel mixture by changing a mounting height of the crankshaft according to a driving condition of the engine, the variable compression ration apparatus comprising: a bearing having a hollow space formed eccentric to a center thereof and rotatably mounted between the upper and lower cylinder blocks, the crankshaft being rotatably inserted in the hollow space; and an operating unit provided at the lower cylinder block and coupled to the bearing so as to control a rotational displacement of the bearing, wherein the bearing comprises: an upper bearing rotatably mounted at the upper cylinder block; and a lower bearing formed asymmetric to the upper bearing, and rotatably mounted at an upper portion of a mounting recess formed at the lower cylinder block; and wherein the upper bearing is wider at a middle portion thereof and relatively narrower at both end portions thereof and the lower bearing is narrower at a middle portion thereof and relatively wider at both end portions thereof; wherein the lower bearing is provided with a protruding portion disposed in the mounting recess; and wherein the operating unit comprises a first hydraulic pressure valve mounted at one side of the mounting recess with reference to the protruding portion.