Patent ID: 6499446
Filing Date: 2002-12-31
Classification: F02B,F16C

Abstract:
A variable compression ratio engine comprising a connecting rod via which a crankshaft that rotates about a crank axis reciprocates a piston within a cylinder, wherein the connecting rod comprises:a first part and a second part that are relatively positionable to set an effective length of the connecting rod and hence a compression ratio for the cylinder; and a locking mechanism that is selectively operable to a locked condition for locking the first part to the second part in a position that sets a given effective length for the connecting rod and to an unlocked condition that allows the first and second parts to be relatively positioned to an effective length different from the given effective length; wherein the first part comprises a through-hole that has a longitudinal axis parallel to the crank axis and the second part comprises a bore that has a longitudinal axis parallel to the crank axis; wherein, the axis of the through-hole is co-axial with the axis of the bore when the connecting rod is set to the given effective length, and the axis of the through-hole is non-co-axial with the axis of the bore when the connecting rod is set to an effective length different from the given effective length; and the locking mechanism comprises first and second elements that are operable to a first position representing the locked condition of the locking mechanism and to a second position representing the unlocked condition of the locking mechanism; wherein, with the first and second parts positioned to set the connecting rod to the given effective length and the first and second elements in the first position, each element bridges a respective end of the through-hole and a respective portion of the bore, thereby locking the first and second parts in the given effective length setting; and wherein, with the first and second elements in the second position, neither element bridges the respective end of the through-hole and the respective end of the bore.