EP4086438A1 - Ein ventiltrieb für den betrieb einer zylinderventilbaugruppe einer brennkraftmaschine - Google Patents

Ein ventiltrieb für den betrieb einer zylinderventilbaugruppe einer brennkraftmaschine Download PDF

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Publication number
EP4086438A1
EP4086438A1 EP22171164.1A EP22171164A EP4086438A1 EP 4086438 A1 EP4086438 A1 EP 4086438A1 EP 22171164 A EP22171164 A EP 22171164A EP 4086438 A1 EP4086438 A1 EP 4086438A1
Authority
EP
European Patent Office
Prior art keywords
outer plunger
plunger
oil
valve
casing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22171164.1A
Other languages
English (en)
French (fr)
Inventor
Harald Fessler
Mathias Binder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
FPT Motorenforschung AG
Original Assignee
FPT Motorenforschung AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by FPT Motorenforschung AG filed Critical FPT Motorenforschung AG
Publication of EP4086438A1 publication Critical patent/EP4086438A1/de
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0005—Deactivating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/181—Centre pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/46—Component parts, details, or accessories, not provided for in preceding subgroups
    • F01L2001/467—Lost motion springs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2810/00—Arrangements solving specific problems in relation with valve gears
    • F01L2810/02—Lubrication

Definitions

  • the present invention relates to a valve train employing disablement of main Valve events, in particular in the field of large displacement internal combustion engines for trucks and work vehicles.
  • Cylinder deactivation is an efficient measure to realize thermal management and improve fuel consumption at low loads.
  • CDA is realized by deactivating the valve lifts and the fueling of some or all cylinders.
  • HLA hydraulic lash adjusting
  • Efficient engine braking systems require also the deactivation of the valve lift profiles implemented for fired operation.
  • the deactivation of the valve lift profiles is usually not crank angle synchronized per cylinder, which means the valve can close from any position. This can lead to extreme seating velocities and engine durability problems.
  • US2014251266 discloses a deactivation mechanism disposed within a main valve train capable to disable conveyance of main valve events from a main valve motion source to a valve via the main valve train.
  • a rocker arm is arranged to swing over a rocker shaft.
  • This shaft is provided with an oil passage to supply a rocker arm duct in any rocker arm positions.
  • the rocker arm duct supplies a lost motion assembly arranged on the bridge of two valves.
  • the lost motion assembly includes an outer plunger arranged in a valves bridge casing and arranged to be pushed downwards by the rocker arm and an inner plunger, arranged in a cavity of the outer plunger.
  • the outer plunger has a side opening extending through the outer plunger wall for receiving a wedge roller or ball.
  • the inner plunger includes one or more recesses shaped to securely receive the one or more wedge rollers or ball when the inner plunger is pushed downward against an inner plunger spring interposed between the bottom of its axial, cavity of the outer plunger and the inner plunger.
  • the central casing of the valves bridge also includes one or more recesses for receiving the one or more wedge rollers or balls in a manner that permits the rollers or balls to lock the outer plunger and the valves bridge together, as shown in figure 1 .
  • the outer plunger spring may bias the outer plunger upward in the central casing of the valve bridge.
  • the inner plunger spring may bias the inner plunger upward in the outer plunger cavity.
  • valve actuation motion applied to the lost motion assembly is not transmitted to the valves bridge body, thus the latter does not move downward to actuate the valves.
  • This downward motion causes the outer plunger to slide downward within the central casing of the valves bridge body against the bias of the outer plunger spring, whose bias force is less relevant than the valve springs one.
  • the hydraulic oil can be pressurized while the hump of the cam is forcing the rocker arm to push the lost motion assembly with the result that valves are immediately closed, impacting against their seats.
  • a solution to avoid this problem is to synchronize the pressurization of the oil in such a way to disconnect the outer plunger from valves bridge only when the rocker arm is in released condition, namely when it is contacting the base circumference of the cam.
  • This synchronization should be carried independently for each of the deactivated/braked cylinders. At high rotation speed, it is difficult to obtain a satisfactory synchronization. In addition, the hydraulic circuit should be complicated due to the implementation of a fast solenoid valve for each cylinder.
  • the main object of the present invention is to provide an auxiliary valve motions employing disablement of main valve events, which overcomes the above problems/drawbacks.
  • the scope of the present invention is to design a system with an intrinsic mechanical fail-safe cylinder deactivation system, which does not depend on any kind of synchronization.
  • the basic idea of the present invention is based on a metered oil relief valve defined between the outer plunger and its casing in the valve bridge.
  • the clearance between the base of the outer plunger and the casing is filled of oil and in case of sudden activation of the lost motion assembly, the oil relief dumps the relative motion between the two set of components.
  • the valve train comprises a valve bridge including a casing wherein a lost motion assembly is slidably inserted, wherein the lost motion assembly includes an outer plunger having a longitudinal development arranged to receive a main rocker arm action and to transmit such action to the valve bridge through a locking element, wherein, said outer plunger includes an axial cavity where an inner plunger is suitable to slide in response of oil pressurization; the lost motion assembly being configured to define a clearance between a bottom portion of the casing and a bottom portion of the outer plunger configured to receive pressurized oil and wherein said casing is provided of a passing through opening to discharge said pressurized oil in such a way to dump a sudden restriction of the clearance caused by lost motion activation.
  • the outer plunger is provided of a tapered pin arranged to penetrate the opening by metering the oil discharge.
  • the rocker arm is provided of an oil passage to supply with oil the lost motion assembly through a swivel foot.
  • the oil is continuously supplied, however, during cylinder deactivation, the oil pressure is increased such that to force the lost motion assembly to disconnect the outer plunger from the valve bridge.
  • a chamber is defined to permit the exertion of the lowering force during pressurization.
  • an oil passage is defined within the body of the outer plunger to continuously refill the clearance between outer plunger and valves bridge casing.
  • second element does not imply the presence of a "first element”, first, second, etc.. are used only for improving the clarity of the description and they should not be interpreted in a limiting way.
  • Figure 2 discloses a preferred embodiment of the invention.
  • the device can be completed with a rocker arm suitable to swing over its rocker shaft and provided of a finger disposed to push downwards the bridge through the lost motion assembly as disclosed in figure 1 of the prior art.
  • a camshaft is provided with at least a hump to define a valve lift event forcing the rocker arm to swing pushing the lost motion assembly such to force the valves opening.
  • the rocker arm can be provided of a roller arranged at the opposite end of the finger, but it could be disposed at the same side of the finger with respect the fulcrum defined by the rocker shaft with camshaft shaped complementary with respect to the one disclosed in figure 1 .
  • the lost motion assembly LMA includes an outer plunger OP and an inner plunger IP arranged inside a cavity CS of the outer plunger, such that the inner plunger can slide in the cavity according to the X axis, as a cylinder/piston coupling.
  • the rocker arm exerts its action, pushing downwards the swivel foot SFO arranged on the top of the outer plunger OP.
  • the inner plunger is encapsulated in the outer plunger and the swivel foot, which closes the outer plunger cavity as a cap.
  • the rocker shaft is provided of a duct to convey hydraulic oil to the lost motion assembly, through the swivel foot SFO of the lost motion assembly.
  • the swivel foot itself is preferably configured as a ball join with its duct FD arranged to interconnect the rocker arm duct with a chamber CH defined within the outer plunger and in particular between the swivel foot and the top portion of the inner plunger IP.
  • a pressurization commanded by a (fast) solenoid valve causes the lowering of the inner plunger IP in the cavity of the outer plunger, such that its recess IPR faces the locking element LE, therefore, when the finger starts pushing the swivel foot, the locking element, shaped as a ball or a wedge, interacts with its seat LES defined in the body of the valves bridge and slides in the recess LES unlocking the lost motion assembly from the valve bridge. Therefore, the finger pushing causes the compression of the outer plunger spring OPS.
  • the latter is interposed between the outer plunger and the bottom portion BP of the casing OCS defined in the valve bridge. Therefore, in the valves bridge
  • the inner spring IPS pushes upwards the inner plunger and the recess IPR is shaped to force the locking element to return in the locking condition, namely partially within seat LES.
  • the inner spring IPS is interposed between the inner plunger and a bottom portion BP1 of the cavity CS of the outer plunger.
  • the casing OCS of the valves bridge VB is provided with a bottom portion BP where a passing through opening MO is arranged to discharge oil in a reservoir ORS.
  • the clearance CC between the bottom portion BP of the casing OCS and the bottom portion BP1 of the outer plunger is continuously filled with oil due to an oil passage connecting such clearance with the chamber CH described above.
  • the oil outflow is metered according to the size of the clearance.
  • the pin has a first section, contiguous with the outer plunger surface, having a shape complimentary with the passing though opening MO.
  • first section and the opening are cylindrical.
  • the pin has a second section, namely a tip, tapered, to carry out the metering of the oil flow during reduction of the clearance.
  • the outer plunger OP has a bottom portion tapered such that the spiral spring OPS is partially enslaved on the outer plunger.
  • the filling channel FP is arranged in the outer plunger connecting the chamber CH with the external surface of the outer plunger in the bottom portion.
  • a further oil passage RP is realized in the valve assembly to discharge oil eventually trapped between the inner plunger and the outer plunger. Such oil would oppose the depression of the inner plunger.
  • a first portion of the further oil passage RP is realized in the inner plunger connecting the lower portion of the cavity CV with the recess IPR.
  • a second portion of the further oil passage is realized in the outer plunger according to a transversal direction with respect to the X axis, such that to connect the recess IPR with the seat LES of the locking element LE.
  • another portion of the further oil passage RP is realized to reach the external surface of the valve bridge. It should be considered that further and different paths can be decided to relief oil trapped between the inner plunger and the bottom portion BP1 of the outer plunger.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Valve Device For Special Equipments (AREA)
EP22171164.1A 2021-05-05 2022-05-02 Ein ventiltrieb für den betrieb einer zylinderventilbaugruppe einer brennkraftmaschine Pending EP4086438A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102021000011516A IT202100011516A1 (it) 2021-05-05 2021-05-05 Un treno valvole per l’azionamento di un gruppo valvole cilindro per motore a combustione interna

Publications (1)

Publication Number Publication Date
EP4086438A1 true EP4086438A1 (de) 2022-11-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP22171164.1A Pending EP4086438A1 (de) 2021-05-05 2022-05-02 Ein ventiltrieb für den betrieb einer zylinderventilbaugruppe einer brennkraftmaschine

Country Status (2)

Country Link
EP (1) EP4086438A1 (de)
IT (1) IT202100011516A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117569888A (zh) * 2024-01-19 2024-02-20 龙口中宇热管理系统科技有限公司 一种发动机动态闭缸气门控制机构、控制方法及发动机

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140251266A1 (en) 2011-07-27 2014-09-11 Jacobs Vehicle Systems, Inc. Auxiliary Valve Motions Employing Disablement of Main Valve Events and/or Coupling of Adjacent Rocker Arms
US9790824B2 (en) * 2010-07-27 2017-10-17 Jacobs Vehicle Systems, Inc. Lost motion valve actuation systems with locking elements including wedge locking elements
EP2975230B1 (de) * 2014-07-15 2018-02-21 Jacobs Vehicle Systems, Inc. Leerlaufventilbetätigungssysteme mit sicherungselementen einschliesslich keilsicherungselementen
US10851682B2 (en) * 2018-06-29 2020-12-01 Jacobs Vehicle Systems, Inc. Engine valve actuation systems with lost motion valve train components, including collapsing valve bridges with locking pins

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9790824B2 (en) * 2010-07-27 2017-10-17 Jacobs Vehicle Systems, Inc. Lost motion valve actuation systems with locking elements including wedge locking elements
US20140251266A1 (en) 2011-07-27 2014-09-11 Jacobs Vehicle Systems, Inc. Auxiliary Valve Motions Employing Disablement of Main Valve Events and/or Coupling of Adjacent Rocker Arms
EP2975230B1 (de) * 2014-07-15 2018-02-21 Jacobs Vehicle Systems, Inc. Leerlaufventilbetätigungssysteme mit sicherungselementen einschliesslich keilsicherungselementen
US10851682B2 (en) * 2018-06-29 2020-12-01 Jacobs Vehicle Systems, Inc. Engine valve actuation systems with lost motion valve train components, including collapsing valve bridges with locking pins

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117569888A (zh) * 2024-01-19 2024-02-20 龙口中宇热管理系统科技有限公司 一种发动机动态闭缸气门控制机构、控制方法及发动机
CN117569888B (zh) * 2024-01-19 2024-04-16 龙口中宇热管理系统科技有限公司 一种发动机动态闭缸气门控制机构、控制方法及发动机

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