Claims
- 1. Apparatus in a compression release engine retarder for limiting the travel of a slave piston in a slave piston cylinder disposed in a brake housing, said slave piston having a head and a stem disposed thereon and said slave piston cylinder having a wall and being connected to a hydraulic circuit so that when hydraulic fluid passes through said wall of said slave piston cylinder at an upper end of said slave piston cylinder, said slave piston moves down along a longitudinal axis toward a lower end of said slave piston cylinder to actuate at least one engine valve, said apparatus comprising:an upper flow port in said slave piston cylinder wall, said upper flow port forming an entrance to a hydraulic fluid supply line; a lower flow port in said slave piston cylinder wall, said lower flow port forming an entrance to a drain passage; and an internal passageway in said slave piston head, said internal passageway providing communication between a fluid volume above said slave piston, said hydraulic fluid supply line and said drain passage; and an electronic trigger valve connected to a common rail, high-pressure plenum, to said upper flow port via said hydraulic fluid supply line and to said drain passage; wherein said slave piston head further comprises an annular channel providing, in a first position of said slave piston relative to said brake housing, communication of said fluid volume with said upper flow port and occlusion of said lower flow port, and in a second position of said slave piston relative to said brake housing, opening of said lower flow port while said upper flow port is nearly occluded, to thereby permit communication between said fluid volume above said slave piston and said drain passage, and wherein in said second position, said at least one engine valve is actuated.
- 2. The apparatus of claim 1, wherein said trigger valve is a three-way, high-pressure, high-speed trigger valve.
- 3. The apparatus of claim 1, further comprising a slave piston spring disposed in said slave piston cylinder and biased to urge said slave piston generally upward against the pressure in said hydraulic circuit.
- 4. The apparatus of claim 1, wherein said head of said slave piston is slidably disposed in said upper end of said slave piston cylinder, and said stem of said slave piston extends longitudinally from said slave piston head into said lower end of said slave piston cylinder.
- 5. The apparatus of claim 1, wherein a first flow area of said upper flow port and a second flow area of said lower flow port vary as a function of the longitudinal position of said slave piston.
- 6. The apparatus of claim 1, wherein said annular channel further comprises a plurality of circumferentially-arranged holes.
- 7. The apparatus of claim 1, wherein said annular channel further comprises a plurality of circumferential grooves.
- 8. The apparatus of claim 1, wherein said internal passageway further comprises a plenum disposed generally in said slave piston head, at least one vertical bore disposed in said slave piston head parallel with said longitudinal axis of said slave piston cylinder, and at least one horizontal bore diametrically spanning said slave piston head, such that said at least one horizontal bore communicates with said slave piston plenum, said at least one vertical bore and said annular channel.
- 9. The apparatus of claim 1, further comprising an automatic lash adjustment hydraulic system for adjusting the lash of said slave piston.
- 10. The apparatus of claim 9, wherein said automatic lash adjustment hydraulic system further comprises:a hydraulic lash adjustor piston slidably disposed inside said slave piston; a hydraulic lash adjustor spring disposed about said a hydraulic lash adjustor piston to urge said hydraulic lash adjustor piston upward; a hydraulic lash adjustor plenum between said slave piston and said hydraulic lash adjustor piston; a check valve between said hydraulic lash adjustor plenum and said hydraulic circuit; and a control valve connected to said hydraulic circuit.
- 11. Apparatus in a compression release engine retarder for adjusting the lash of a slave piston in a slave piston cylinder, said slave piston having a head and a stem disposed thereon and said slave piston cylinder, disposed in a brake housing, having a wall and being connected to a hydraulic circuit so that when hydraulic fluid passes through an upper flow port and a lower flow port in said wall of said slave piston cylinder, said slave piston moves, relative to said brake housing, down along a longitudinal axis of said slave piston cylinder toward a lower end of said slave piston cylinder to actuate at least one engine valve, said apparatus comprising:a sleeve disposed around said slave piston and contained substantially in said brake housing, wherein said sleeve further comprises at least one vertical bore disposed in a sleeve extension, wherein said at least one vertical bore is parallel with said longitudinal axis of said slave piston cylinder and connects a first fluid volume above said slave piston with a second fluid volume above said sleeve; and means for maintaining said sleeve in an adjusted position, connected to said sleeve.
- 12. The apparatus of claim 11, wherein said sleeve further comprises a first set of threads and said brake housing further comprises a second set of threads, said first and second sets of threads being capable of alignment thereby to screw said sleeve into said brake housing.
- 13. The apparatus of claim 12, wherein said sleeve extension extends above said brake housing, said sleeve extension further comprising a continuation of said first set of threads.
- 14. The apparatus of claim 13, wherein said apparatus further comprises a locking ring threadably engaged to said sleeve extension, for securing said sleeve in an adjusted position.
- 15. The apparatus of claim 11, wherein said apparatus further comprises at least one hold-down bolt for securing said sleeve in an adjusted position.
- 16. The apparatus of claim 15, wherein said apparatus further comprises a plurality of shims of varying thickness for adjusting said lash of said slave piston.
- 17. The apparatus of claim 13, wherein said apparatus further comprises an adjusting screw threadably engaged with said sleeve.
- 18. Apparatus, in a compression release engine retarder having a common rail, variable valve actuation system, for limiting the travel and adjusting the lash of a slave piston in a slave piston cylinder, said slave piston having a head and a stem disposed thereon and said slave piston cylinder, disposed in a brake housing, having a wall and being connected to a hydraulic circuit so that when hydraulic fluid passes through said wall of said slave piston cylinder at an upper end of said slave piston cylinder, said slave piston moves down along a longitudinal axis toward a lower end of said slave piston cylinder to actuate at least one engine valve, said apparatus comprising:an upper flow port in said slave piston cylinder wall, said upper flow port forming an entrance to a hydraulic fluid supply line; a lower flow port in said slave piston cylinder wall, said lower flow port forming an entrance to a drain passage; a slave piston spring disposed in said slave piston cylinder and biased to urge said slave piston generally upward against the pressure in said hydraulic circuit; said slave piston head, slidably disposed in said upper end of said slave piston cylinder, having an annular channel, said annular channel providing, in a first position of said slave piston relative to said brake housing, communication of said fluid volume with said upper flow port and occlusion of said lower flow port, and in a second position of said slave piston relative to said brake housing, opening of said lower flow port while said upper flow port is nearly occluded, to thereby permit communication between said fluid volume above said slave piston and said drain passage, and wherein in said second position, said at least one engine valve is actuated; said slave piston stem, extending longitudinally from said slave piston head into said lower end of said slave piston cylinder; an internal passageway in said slave piston, comprising a plenum disposed generally in said slave piston head, at least one vertical piston head bore disposed in said slave piston head parallel with said longitudinal axis of said slave piston cylinder, and at least one horizontal bore diametrically spanning said slave piston head, such that the at least one horizontal bore communicates with said plenum, said at least one vertical piston head bore and said annular channel, providing communication between a fluid volume above said slave piston, said hydraulic fluid supply line and said drain passage when said annular channel and said lower flow port are aligned; an electronic trigger valve connected to a common rail, high-pressure plenum, to said upper flow port via said hydraulic fluid supply line and to said drain passage; a sleeve disposed around said slave piston and contained substantially in said brake housing, wherein said sleeve further comprises at least one vertical sleeve bore disposed in a sleeve extension, wherein said at least one vertical sleeve bore is parallel with said longitudinal axis of said slave piston cylinder and connects a first fluid volume above said slave piston with a second fluid volume above said sleeve; and means for maintaining said sleeve in an adjusted position, connected to said sleeve.
- 19. The apparatus of claim 18, wherein said trigger valve is a three-way, high-pressure, high-speed trigger valve.
- 20. The apparatus of claim 18, wherein said annular channel further comprises a plurality of circumferentially-arranged holes.
- 21. The apparatus of claim 18, wherein said annular channel further comprises a plurality of circumferential grooves.
- 22. The apparatus of claim 18, wherein said sleeve further comprises a first set of threads and said brake housing further comprises a second set of threads, said first and second sets of threads being capable of alignment thereby to screw said sleeve into said brake housing.
- 23. The apparatus of claim 18, wherein said sleeve extension extends above said brake housing, said sleeve extension further comprising a continuation of said first set of threads.
- 24. The apparatus of claim 18, further comprising a locking ring threadably engaged to said sleeve extension, for securing said sleeve in an adjusted position.
- 25. The apparatus of claim 18, further comprising at least one hold-down bolt for securing said sleeve in an adjusted position.
- 26. The apparatus of claim 18, further comprising a plurality of shims of varying thickness for adjusting the lash of said slave piston.
- 27. The apparatus of claim 18, further comprising an adjusting screw threadably engaged with said sleeve.
CROSS-REFERENCE TO RELATED PATENT APPLICATION
This application relates to and claims priority on United States Provisional Application Serial No. 60/097,113 filed Aug. 19, 1998 and entitled “Hydraulically Activated Fail-Safe Stroke-Limiting Piston.”
US Referenced Citations (34)
Provisional Applications (1)
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Number |
Date |
Country |
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60/097113 |
Aug 1998 |
US |