초록 ▼

Methods and apparatus for providing bleeder-type and compression-release engine braking in an internal combustion engine are disclosed. For bleeder-type engine braking, the exhaust valve is maintained at a small and relatively constant lift throughout all or much of the engine cycle. The engine brak

Methods and apparatus for providing bleeder-type and compression-release engine braking in an internal combustion engine are disclosed. For bleeder-type engine braking, the exhaust valve is maintained at a small and relatively constant lift throughout all or much of the engine cycle. The engine braking may be combined with exhaust gas recirculation, variable exhaust brake, and/or operation of a variable geometry turbocharger.

대표청구항 ▼

What is claimed is: 1. A method of actuating intake and exhaust engine valves in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the steps of: opening at least one intake valve during an intake stroke of the engine cylinder; and providing a substan

What is claimed is: 1. A method of actuating intake and exhaust engine valves in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the steps of: opening at least one intake valve during an intake stroke of the engine cylinder; and providing a substantially constant lift to at least one exhaust valve during a plurality of successive intake, compression, expansion, and exhaust strokes of the engine cylinder. 2. The method of claim 1 further comprising the step of modifying the lift of at least one exhaust valve during successive exhaust strokes of the engine cylinder, wherein said modified lift is different than the lift attained by the same exhaust valve during positive power operation. 3. The method of claim 2 wherein the at least one exhaust valve provided with a substantially constant lift and the at least one exhaust valve provided with modified lift are the same exhaust valve. 4. The method of claim 2 wherein the at least one exhaust valve provided with a substantially constant lift and the at least one exhaust valve provided with modified lift are different exhaust valves associated with the engine cylinder. 5. The method of claim 2 wherein the step of opening at least one intake valve during the intake stroke is delayed relative to opening of the same intake valve for a main intake event during positive power operation. 6. The method of claim 2 further comprising the step of advancing a closing time of the at least one intake valve relative to the closing time of the same intake valve for a main intake event during positive power operation. 7. The method of claim 2 wherein the step of modifying the lift of the at least one exhaust valve comprises delaying the opening time of the at least one exhaust valve compared to the opening time of the same exhaust valve for a main exhaust event during positive power operation. 8. The method of claim 1 further comprising the step of opening the at least one exhaust valve for a brake gas recirculation event. 9. The method of claim 1 wherein the step of opening at least one intake valve during the intake stroke is delayed relative to opening of the same intake valve for the intake stroke during positive power operation. 10. The method of claim 9 further comprising the step of advancing a closing time of the at least one intake valve relative to the closing time of the same intake valve for the intake stroke during positive power operation. 11. The method of claim 1 further comprising the step of advancing a closing time of the at least one intake valve relative to the closing time of the same intake valve for the intake stroke during positive power operation. 12. The method of claim 1 further comprising the step of actuating an exhaust restriction device to regulate exhaust back pressure applied to the engine cylinder. 13. A method of actuating at least one exhaust valve in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the step of: maintaining the at least one exhaust valve open with a substantially constant lift during intake, compression, expansion, and exhaust strokes of the engine cylinder. 14. A method of actuating engine valves including at least one exhaust valve in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the steps of: maintaining the at least one exhaust valve open with a substantially constant lift during compression, expansion, and exhaust strokes of the engine cylinder; and maintaining the at least one exhaust valve closed during at least a portion of an intake stroke of the engine cylinder. 15. The method of claim 14 further comprising the step of modifying the lift of the at least one exhaust valve during successive exhaust strokes of the engine cylinder, wherein said modified lift is different than the lift attained by the same exhaust valve during positive power operation. 16. The method of claim 15 further comprising the step of delaying an opening time of at least one intake valve in the engine cylinder relative to the opening time of the same intake valve for a main intake event during positive power operation. 17. The method of claim 15 further comprising the step of advancing a closing time of at least one intake valve in the engine cylinder relative to the closing time of the same intake valve for a main intake event during positive power operation. 18. The method of claim 15 wherein the step of modifying the lift of the at least one exhaust valve comprises delaying the opening time of the at least one exhaust valve compared to the opening time of the same exhaust valve for a main exhaust event during positive power operation. 19. The method of claim 14 further comprising the step of opening the at least one exhaust valve for a brake gas recirculation event. 20. The method of claim 14 further comprising the step of delaying an opening time of at least one intake valve in the engine cylinder relative to the opening time of the same intake valve for a main intake event during positive power operation. 21. The method of claim 20 further comprising the step of advancing a closing time of the at least one intake valve relative to the closing time of the same intake valve for the main intake event during positive power operation. 22. The method of claim 14 further comprising the step of advancing a closing time of at least one intake valve in the engine cylinder relative to the closing time of the same intake valve for a main intake event during positive power operation. 23. A method of actuating intake and exhaust valves in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the steps of: actuating at least one intake valve during an intake stroke of the engine cylinder using a variable valve actuation system; and actuating at least one exhaust valve during at least portions of compression, expansion, and exhaust stokes of the engine cylinder using an engine braking device. 24. The method of claim 23 further comprising the step of actuating the at least one exhaust valve during at least a portion of the intake stroke of the engine cylinder using the engine braking device. 25. The method of claim 23 wherein actuation of the at least one exhaust valve provides bleeder braking. 26. The method of claim 23 wherein actuation of the at least one exhaust valve provides compression-release braking. 27. The method of claim 23 further comprising the steps of: determining the magnitude of engine braking that is desired; and attempting to provide the determined magnitude of engine braking by selectively varying the number of engine cylinders used for engine braking. 28. The method of claim 23 further comprising the steps of: determining the magnitude of engine braking that is desired; and attempting to provide the determined magnitude of engine braking by selectively adjusting the actuation of the at least one exhaust valve. 29. The method of claim 23 further comprising the steps of: determining the magnitude of engine braking that is desired; and attempting to provide the determined magnitude of engine braking by selectively adjusting the actuation of the at least one intake valve. 30. The method of claim 23 further comprising the steps of: determining the magnitude of engine braking that is desired; and attempting to provide the determined magnitude of engine braking by selectively adjusting the setting of a variable geometry turbocharger associated with the engine. 31. The method of claim 23 further comprising the step of providing at least one exhaust valve with modified lift during successive exhaust strokes of the engine cylinder, wherein said modified lift is different than the lift attained by the same exhaust valve during positive power operation. 32. The method of claim 23 wherein the step of actuating at least one intake valve during the intake stroke is delayed relative to actuation of the same intake valve for the intake stroke during positive power operation. 33. The method of claim 23 further comprising the step of advancing a closing time of the at least one intake valve relative to the closing time of the same intake valve for the intake stroke during positive power operation. 34. The method of claim 23 further comprising the step of actuating an exhaust restriction device to regulate exhaust back pressure applied to the engine cylinder. 35. An apparatus for actuating at least one exhaust valve in an internal combustion engine cylinder to produce a main exhaust event during positive power operation and an engine braking effect during engine braking operation, said apparatus comprising: means for opening the at least one exhaust valve for the main exhaust event during an engine exhaust stroke; and means for maintaining the at least one exhaust valve open with a substantially constant lift during engine intake, compression, expansion, and exhaust strokes. 36. An apparatus for actuating at least one exhaust valve in an internal combustion engine cylinder to produce a main exhaust event during positive power operation and an engine braking effect during engine braking operation, said apparatus comprising: means for opening the at least one exhaust valve for the main exhaust event during an engine exhaust stroke; and means for maintaining the at least one exhaust valve open with a substantially constant lift during substantially all of engine compression, expansion, and exhaust strokes. 37. A method of actuating intake and exhaust valves in an internal combustion engine cylinder to produce an engine braking effect, said method comprising the steps of: determining an engine braking power goal; implementing an engine braking method based at least in part on the engine braking power goal, said engine braking method being selected from the group consisting of one or more of: full bleeder braking, partial bleeder braking, compression-release braking, two-cycle braking, four-cycle braking, and exhaust back pressure regulation; actuating one or more engine valves based at least in part on the engine braking method; and determining whether the engine braking goal is being met. 38. The method of claim 37 further comprising the steps of: determining whether to implement two-stroke engine braking based at least in part on the determination of whether the engine braking goal is being met; and adjusting the actuation of one or more exhaust valves based at least in part on the determination of whether to implement two-stroke engine braking. 39. The method of claim 38 further comprising the step of: adjusting the actuation of one or more intake valves based at least in part on the determination of whether to implement two-stroke engine braking. 40. The method of claim 39 further comprising the step of: adjusting exhaust back pressure based at least in part on the determination of whether the engine braking goal is being met. 41. The method of claim 37 further comprising the steps of: determining whether to implement two-stroke engine braking based at least in part on the determination of whether the engine braking goal is being met; and adjusting of the actuation of one or more intake valves based at least in part on the determination of whether to implement two-stroke engine braking. 42. The method of claim 37 further comprising the steps of: adjusting exhaust back pressure based at least in part on the determination of whether the engine braking goal is being met. 43. The method of claim 23 wherein the step of actuating the at least one exhaust valve comprises providing at least one brake gas recirculation event and at least one compression-release engine braking event per engine cycle. 44. The method of claim 23 wherein the step of actuating the at least one exhaust valve comprises providing at least two brake gas recirculation events and at least two compression-release engine braking events per engine cycle. 45. The method of claim 2 wherein the step of modifying the lift of the at least one exhaust valve comprises advancing the closing time of the at least one exhaust valve compared to the closing time of the same exhaust valve for a main exhaust event during positive power operation. 46. The method of claim 15 wherein the step of modifying the lift of the at least one exhaust valve comprises advancing the closing time of the at least one exhaust valve compared to the closing time of the same exhaust valve for a main exhaust event during positive power operation. 47. The method of claim 23 further comprising the steps of: determining the magnitude of engine braking that is desired; and selectively modifying the braking method in an attempt to provide the determined magnitude of engine braking.