Claims
- 1. 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.
- 2. A variable compression ratio engine as set forth in claim 1 in which the bore comprises opposite ends disposed at opposite ends of the through-hole, the first element bridges one end of the through-hole and one end of the bore when the elements are in the first position, the second element bridges the other end of the through-hole and the other end of the bore when the elements are in the first position, and further including a third element disposed within the one end of the bore, a fourth element disposed within the other end of the bore, and bias force sources urging the third element toward the first element and the fourth element toward the second element.
- 3. A variable compression ratio engine as set forth in claim 2 in which the first and second elements comprise confronting faces having features that allow hydraulic fluid delivered to the confronting faces, when the first and second parts are setting the connecting rod to the given effective length and the first and second elements are in the first position, to operate the first and second elements to the second position against forces exerted by the bias force sources.
- 4. A variable compression ratio engine as set forth in claim 3 in which the bias force sources comprise a first spring disposed in the one end of the bore and a second spring disposed in the other end of the bore.
- 5. A variable compression ratio engine as set forth in claim 1 in which the elements, the through-hole, and the bore have circular transverse cross sections.
- 6. A variable compression ratio engine as set forth in claim 1 in which the elements, the through-hole, and the bore have oval transverse cross sections that comprise flat opposite faces that are perpendicular to a longitudinal axis of the connecting rod.
- 7. A variable compression ratio engine as set forth in claim 1 including a further locking mechanism that is selectively operable to a locked condition for locking the first part to the second part in the position where the first and second parts have an effective length different from the given effective length and to an unlocked condition that allows the first and second parts to be relatively positioned from the position where the first and second parts have an effective length different from the given effective length to the position where the first and second parts have the given effective length.
- 8. A variable compression ratio engine as set forth in claim 7 in which the connecting rod connects to the crankshaft via a crank pin having an axis parallel to the crank axis, and the two locking mechanisms are disposed diametrically opposite each other about the crank pin axis.
- 9. A variable compression ratio engine as set forth in claim 7 in which the further locking mechanism comprises first and second elements that are operable to a first position representing the locked condition of the further locking mechanism and to a second position representing the unlocked condition of the further locking mechanism.
- 10. A variable compression ratio engine as set forth in claim 9 in which the first part comprises a further through-hole that has a longitudinal axis parallel to the crank axis, the second part comprises a further bore that has a longitudinal axis parallel to the crank axis, the first element of the further locking mechanism bridges one end of the further through-hole and one end of the further bore when the elements of the further locking mechanism are in their first position, the second element of the further locking mechanism bridges the other end of the further through-hole and the other end of the further bore when the elements of the further locking mechanism are in their first position, and the first element of the further locking mechanism is disposed entirely within the one end of the further bore and the second element of the further locking mechanism is disposed entirely within the other end of the further bore when the elements of the further locking mechanism are in their second position.
- 11. A variable compression ratio engine as set forth in claim 10 further including a spring disposed within the one end of the further bore for resiliently urging the first element of the further locking mechanism toward the further through-hole, a spring disposed within the other end of the further bore for resiliently urging the second element of the further locking mechanism toward the further through-hole, and a spacer disposed within the further through-hole for separating the first and second elements of the further locking mechanism when the first and second elements of the further locking mechanism are in their first position.
- 12. A variable compression ratio engine as set forth in claim 11 in which the spacer element comprises a passage for conveying hydraulic fluid to the first and second elements of the further locking mechanism to operate the first and second elements of the further locking mechanism from their first position to their second position.
- 13. 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.
- 14. A variable length connecting rod as set forth in claim 13 wherein the first locking mechanism further comprises third and fourth elements disposed entirely within the first bore both when the first locking mechanism is releasably locking the two parts in the first effective length setting and when the first locking mechanism has been released from locking the two parts in the first effective length setting.
- 15. A variable length connecting rod as set forth in claim 14 including bias force sources acting on the third and fourth elements to urge the third and fourth elements toward the first and second elements of the first locking mechanism respectively.
- 16. A variable length connecting rod as set forth in claim 15 in which the first and second elements of the first locking mechanism comprise confronting faces having features that allow hydraulic fluid delivered to the confronting faces, when the first locking mechanism is releasably locking the two parts in the first effective length setting, to act on the confronting faces to cause release of the first locking mechanism from locking the two parts in the first effective length setting.
- 17. A variable length connecting rod as set forth in claim 14 including bias force sources acting on the first and second elements of the second locking mechanism to urge the first and second elements of the second locking mechanism toward the second through-hole, and a spacer element disposed within the second through-hole for separating the first and second elements of the second locking mechanism when the second locking mechanism is releasably locking the two parts in the second effective length setting.
- 18. A variable length connecting rod as set forth in claim 17 in which the spacer element comprises a passage for conveying hydraulic fluid to the first and second elements of the second locking mechanism to release the second locking mechanism from locking the two parts in the second effective length setting.
REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE
This application is related to the following commonly owned patent applications filed of even date and expressly incorporated in their entirety herein by reference: Ser. No. 09/691,668, VARIABLE COMPRESSION RATIO CONNECTING RODS; Ser. No. 09/691,669, VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISM; Ser. No. 09/691,306, VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISM; Ser. No. 09/691,667, HYDRAULIC CIRCUIT FOR UNLOCKING VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISMS; Ser. No. 09/690/951, HYDRAULIC CIRCUIT HAVING ACCUMULATOR FOR UNLOCKING VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISMS; Ser. No. 09/691,666, APPARATUS FOR VARYING THE COMPRESSION RATIO OF AN INTERNAL COMBUSTION ENGINE; Ser. No. 09/690,961, SYSTEM AND METHOD FOR VARYING THE COMPRESSION RATIO OF AN INTERNAL COMBUSTION ENGINE VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISM; and Ser. No. 09/690,946, PULSE-OPERATED VARIABLE COMPRESSION RATIO CONNECTING ROD LOCKING MECHANISM Ser. No. 09/690,946, filed Oct. 18, 2000.
US Referenced Citations (16)
Foreign Referenced Citations (1)
Number |
Date |
Country |
03092552 |
Apr 1991 |
JP |