Variable compression ratio connecting rod locking mechanism II
AssigneeFord Global Technologies, LLC
InventorsV. Durga Nageswar Rao, Mark Michael Madin, Yash Andrew Imai
Life of this patent
Estimating the term…
Abstract
A variable length connecting rod (12) has a first locking mechanism (36) for releasably locking connecting rod parts in a first effective length setting (FIG. 7) for the rod, and a second locking mechanism (38) for releasably locking the connecting rod parts in a second effective length setting to change the compression ratio for an engine cylinder. When a length change is to be made, hydraulic fluid unlocks a locked one of the locking mechanisms, allowing inertial force to effect the length change during an engine cycle. At completion of a length change, the other locking mechanism automatically unlocks.
Claims18
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 the first and second elements are disposed entirely within the through-hole when in their second position, thereby allowing the first and second parts to be set to an effective length different from the given effective length.
A variable length connecting rod for reciprocating a piston within a cylinder of an engine in consequence of rotation of a crankshaft of the engine about a crank axis, 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;
- wherein the first part comprises a first through-hole that has a longitudinal axis parallel to the crank axis and a second through-hole that has a longitudinal axis parallel to the crank axis;
- wherein the second part comprises a first bore that has a longitudinal axis parallel to the crank axis and a second bore that has a longitudinal axis parallel to the crank axis;
- wherein, the axis of the first through-hole is co-axial with the axis of the first bore when the first and second parts are positioned to set a first effective length for the connecting rod but is non-co-axial with the axis of the first bore when the first and second parts are positioned to set a second effective length for the connecting rod;
- wherein, the axis of the second through-hole is non-co-axial with the axis of the second bore when the first and second parts are positioned to set the first effective length for the connecting rod but is co-axial with the axis of the second bore when the first and second parts are positioned to set the second effective length for the connecting rod;
- a first locking mechanism that acts via the first through-hole and the first bore for releasably locking the two parts in the first effective length setting;
- and
- a second locking mechanism that acts via the second through-hole and the second bore for releasably locking the two parts in the second effective length setting;
- wherein the first locking mechanism comprises first and second elements that are disposed entirely within the first through-hole when the first locking mechanism has been released from locking the two parts in the first effective length setting;
- and
- wherein the second locking mechanism comprises first and second elements that are disposed entirely within the second bore when the second locking mechanism has been released from locking the two parts in the second effective length setting.
Dependencies are inferred from the claim text.