EP1426570A2 - Mechanismus zur variablen Ventilsteuerung mit geringer Reibung - Google Patents

Mechanismus zur variablen Ventilsteuerung mit geringer Reibung Download PDF

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Publication number
EP1426570A2
EP1426570A2 EP04000193A EP04000193A EP1426570A2 EP 1426570 A2 EP1426570 A2 EP 1426570A2 EP 04000193 A EP04000193 A EP 04000193A EP 04000193 A EP04000193 A EP 04000193A EP 1426570 A2 EP1426570 A2 EP 1426570A2
Authority
EP
European Patent Office
Prior art keywords
camshaft
valve
cam
accordance
engine
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.)
Withdrawn
Application number
EP04000193A
Other languages
English (en)
French (fr)
Inventor
Ronald Jay Pierik
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.)
Delphi Technologies Inc
Original Assignee
Delphi Technologies Inc
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 Delphi Technologies Inc filed Critical Delphi Technologies Inc
Priority claimed from EP01202103A external-priority patent/EP1167705B1/de
Publication of EP1426570A2 publication Critical patent/EP1426570A2/de
Withdrawn legal-status Critical Current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
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0021—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio
    • F01L13/0026—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio by means of an eccentric
    • 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
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0063—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot
    • 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
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0063—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot
    • F01L2013/0073—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot with an oscillating cam acting on the valve of the "Delphi" type
    • 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
    • F01L2305/00—Valve arrangements comprising rollers

Definitions

  • the present invention is related to variable valve train systems for use on internal combustion engines; more particularly, to devices for controllably varying the lift of valves in such engines; and most particularly, to a variable valve train device driven by an engine camshaft and employing a command link pivotably mounted on the engine head and not on the camshaft that controllably varies the lift of the intake valves to control engine load.
  • a controllable variable valve train can obviate the need for a throttle valve and EGR valve in a gas or diesel internal combustion engine.
  • variable valve train (VVT) actuation devices and valve timing mechanisms for enhancing engine performance are known in the automotive art, but commercial use of such devices generally has been impractical because of cost, size, and/or operating limitations which have limited their true value and practicality.
  • VVT variable valve train
  • variable valve actuation mechanisms employ a segmented single shaft crank rocker (SSCR) for operating individual or multiple engine valves by engaging a linkage with a rotary eccentric, preferably a rotary cam, to drive an oscillatable rocker cam.
  • SSCR segmented single shaft crank rocker
  • the disclosed SSCR mechanism has four moving components (two arms, a rocker, and a cam) and thus can be expensive to manufacture and subject to premature wear at a plurality of joints.
  • springs are required to maintain contact between an input cam and a roller follower, which springs tend to increase friction and limit maximum operating speed.
  • the coordinating frames of these devices are rotatably mounted on the camshaft itself, thus creating unavoidable and undesirable frictional losses therebetween.
  • variable valve train device which can be economically mass-produced for commercial use in vehicles powered by internal combustion engines.
  • variable valve train device in accordance with the invention is provided for installation on an internal combustion engine having a rotary camshaft.
  • the device is capable of interfacing with a camshaft having adjacent valve-opening and valve-closing lobes for each valve.
  • the variable valve train device is mounted on the engine head and is pivotable about the camshaft without bearing upon the camshaft to alter the timing and lift of an engine valve, typically a fuel intake valve.
  • a command link controlling the rotational position of the apparatus with respect to the camshaft is rotationally disposed on its outer surface in a cylindrical shell bearing mounted on the engine head coaxial with the camshaft.
  • the shell bearing is variably supported by an hydraulic lash adjuster (HLA) or an adjustable ball joint mount, or the like, such that mechanical lash in the system may be minimized.
  • the command link includes an arcuate ring gear portion which meshes with a control shaft gear of the engine for advancing or retarding the valve timing.
  • the command link pivotably supports a rocker assembly having first and second rollers, or sliding pad cam followers, for following the rotary motion of valve-opening and valve-closing cam lobes.
  • the rocker assembly is pivotably linked via an output link to an output cam element, preferably a partial cam having minimal friction dependence on the camshaft, disposed between the camshaft and a conventional roller finger follower for actuating the valve.
  • the output link and output cam are doubled symmetrically about the command link, and a dual rocker arm cooperates with both output links for simultaneous and identical actuation of both output cams and valves.
  • a plurality of cylinders in an internal combustion engine are provided with an individual device in accordance with the present invention.
  • the disclosed invention is thus capable of controlling engine load and peak engine torque directly at the cylinder head without resort to a conventional throttle and exhaust gas recirculation (EGR) valve.
  • EGR exhaust gas recirculation
  • the invention is also useful for variably controlling the valves of other apparatus incorporating poppet-type valves, for example, compressors for air and other gases.
  • variable valve train device in accordance with the invention may be better appreciated by first considering an analogous prior art variable valve train device as shown in FIGS. 1 and 2.
  • VVT device 10 generally indicates a prior art embodiment of a VVT device which is operable to vary valve timing and lift in an operating engine 12 having a valve 14 actuated through a follower 16.
  • VVT device 10 includes a rotary input cam lobe 18 carried, for example, on a camshaft 19 and rotatable on a rotational primary axis 20.
  • Device 10 further includes a control frame 22 including a carrier link or lever 23 which is pivotable about the primary axis 20.
  • Frame 22 is externally drivable by teeth 24 that are engaged by mating teeth 26 formed on a control gear 28 that may be oscillated about an axis 30 parallel to the primary axis.
  • a rocker 32 is pivotably connected at one end with frame 22 at a pivot axis 34 spaced from the primary axis 20.
  • Rocker 32 has a distal end 36 and an eccentric follower 38 in the form of a roller or other suitable means for engaging cam lobe 18 and acting as a cam follower.
  • a secondary lever 40 has one end mounted on and pivotable about the primary axis 20. Secondary lever 40 has a distal end 44 spaced from the axis 20 and operatively connected with the distal end 36 of rocker 32. This operative connection is made by link 46 pivotably interconnecting the two distal ends 44,36. Secondary lever 40 also includes at said one end an oscillating cam 48 having a base circle portion 50 centered on the primary axis 20 and a valve lift portion 52 extending eccentrically outward from the base circle portion. Cam 48 engages a cam follower 16, which may be a known roller finger follower, in a reciprocating motion directly acting upon valve 14 for opening and closing the valve.
  • the rotary cam lobe 18 is driven in timed relation with the engine crankshaft by any suitable means, such as a camshaft drive.
  • the control member 22 is positioned in a predetermined orientation which is angularly adjustable to vary valve lift and timing but remains fixed when no change is desired.
  • the rocker 32 is pivoted outward (up) about the pivot axis 34 located on the control member 22. This raises link 46, causing the secondary lever 40 to rotate clockwise about the primary axis 20 to slide or rock the oscillating cam 48 against the direct acting follower 16.
  • Numeral 110 generally indicates an embodiment of a VVT device in accordance with the invention which is operable to vary valve timing and lift in an operating engine 12 having a valve 14 actuated by a roller finger follower 116.
  • Engine 12 includes a valve-opening eccentric lobe 18 and an adjacent valve-closing lobe 21 fixedly disposed on a camshaft 19 which is rotatable on a rotational primary axis 20.
  • Command link 122 is generally cylindrically arcuate about an axis coincident with primary axis 20 and has an outer bearing surface 124 which is received in a cylindrical shell bearing 126 mounted on the engine head.
  • Bearing 126 preferably is supported adjustably to the head so that lash among the various components of VVT device 110 may be minimized.
  • bearing 126 may be supported by an hydraulic lash adjuster 128 (HLA), itself mounted in the head and drawing oil from a known gallery in the engine head.
  • HLA hydraulic lash adjuster 128
  • bearing 126 may be supported by an adjustable mount 130, as shown in FIGS. 8 and 9, wherein a ball end 131 is adjustably threaded onto bearing 126 and mates with a ball socket (not shown) in the engine head.
  • the shell bearing 126 is adjustable radially from camshaft 19. This relaxes the manufacturing tolerances of various components of the device and permits lash between the components to be eliminated after assembly by adjustment of the support for the shell bearing. Such adjustment occurs either automatically via an hydraulic lash adjuster 128 or mechanically by screw adjustment of mount 130. Such adjustment effectively removes mechanical lash between the control shaft gear and the ring gear on the command link; between the ring gear and the rocker pin; between the rocker pin and the rocker assembly; between the valve-opening cam and its follower; and between the valve-closing cam and its follower.
  • a rocker assembly 132 is pivotably connected at a proximal end 133 with command link 122 at a pivot axis 134 spaced from and parallel to primary axis 20.
  • a distal end 136 of rocker 132 is pivotably connected to link 138 which in turn is pivotably connected to a novel partial output cam 140 disposed between camshaft 19 and roller finger follower 116.
  • rocker assembly 132 includes a first follower, for example, first roller 142, for following valve-opening cam lobe 18; and a second follower, for example, second roller 144, for following valve-closing cam lobe 21.
  • each roller is supported on an outer surface thereof, rather than being axially supported, in a cylindrical bearing mount 146,148, respectively, formed in rocker assembly 132.
  • Each roller is axially retained by a roller retainer 150,152, respectively.
  • rollers 142 and 144 are disposed on opposite sides of pivot axis 134 such that the eccentric of lobe 18 drives roller 142 away from primary axis 20, thus opening the engine valve 14, and the eccentric of lobe 21 drives roller 144 away from axis 20, thus returning the VVT linkages to the valve closed position without resort to energy-consuming return springs.
  • the two lobes and followers thus cooperate to control at all times the action of rocker assembly 132 without springs.
  • Partial output cam 140 is an arcuate wedge rotationally displaceable between camshaft 19 and roller finger follower 116 to vary the spacing therebetween, and thus to control the opening and closing of valve 14, by being rotated about camshaft 19. Because cam 140 makes limited angular contact with camshaft 19, in contrast with prior art oscillating cam 48 which makes 360° contact, cam 140 can provide a significant reduction in frictional drag of apparatus 110 as compared to prior art apparatus 10. In addition, use of cam 140 reduces the number of parts and hence the cost of the device. It also enhances ease of assembly by allowing use of a one-piece camshaft because it is not required to be fitted to the camshaft itself.
  • camshaft 19 is driven in timed relation with the engine crankshaft by any suitable means, such as a conventional camshaft drive.
  • Command link 122 is positioned in a predetermined orientation which is angularly adjustable by rotation of control gear 28 which meshes with ring gear portion 123 of the command link to vary valve lift and timing but remains fixed when no change is desired.
  • the rocker assembly 132 is pivoted about the pivot axis 134 on command link 122. This causes partial output cam 140 to rotate counterclockwise (in FIGS. 3 and 4) about the primary axis 20 to displace the roller finger follower 116 away from axis 20, thus opening valve 14.
  • roller 142 Upon further rotation of camshaft 19 past the maximum eccentricity of lobe 18, roller 142 is retracted towards primary axis 20 as roller 144 is urged away from axis 20 by lobe 21.
  • Rocker assembly 132 and link 138 urge partial output cam 140 to rotate clockwise, allowing valve 14 to close against seat 15.
  • the control frame 122 is rotated counterclockwise, analogous to the actuation described hereinabove for prior art VVT device 10.
  • a preferred embodiment 110' of the invention is adapted for actuating two valves 14,14' acting in parallel.
  • a second link 138' is connected to rocker assembly 132 and to a second partial output cam 140' which actuates valve 14' in parallel with valve 14.
  • partial output cam(s) 140 may be replaced alternatively by full-fitting cam(s) 140a connected to link(s) 138 and actuated thereby identically to cam(s) 140.
  • Cam 140a is preferably formed as two portions joined around camshaft 19 as by bolts 141: a linking portion 143 and an eccentric portion 145.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)
EP04000193A 2000-06-30 2001-06-01 Mechanismus zur variablen Ventilsteuerung mit geringer Reibung Withdrawn EP1426570A2 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US21525300P 2000-06-30 2000-06-30
US215253P 2000-06-30
EP01202103A EP1167705B1 (de) 2000-06-30 2001-06-01 Reibungsarme variable Ventilbetätigungsvorrichtung

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
EP01202103A Division EP1167705B1 (de) 2000-06-30 2001-06-01 Reibungsarme variable Ventilbetätigungsvorrichtung
EP01202103A Division-Into EP1167705B1 (de) 2000-06-30 2001-06-01 Reibungsarme variable Ventilbetätigungsvorrichtung

Publications (1)

Publication Number Publication Date
EP1426570A2 true EP1426570A2 (de) 2004-06-09

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EP04000193A Withdrawn EP1426570A2 (de) 2000-06-30 2001-06-01 Mechanismus zur variablen Ventilsteuerung mit geringer Reibung

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EP (1) EP1426570A2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1985816A1 (de) * 2007-03-05 2008-10-29 PIAGGIO & C. S.p.A. System zur durchgehenden Änderung der Anhebung und der Phase von Ventilen in einem Verbrennungsmotor
CN101550853B (zh) * 2009-05-08 2011-04-06 上海汽车集团股份有限公司 发动机气门连续可变驱动机构

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1985816A1 (de) * 2007-03-05 2008-10-29 PIAGGIO & C. S.p.A. System zur durchgehenden Änderung der Anhebung und der Phase von Ventilen in einem Verbrennungsmotor
CN101550853B (zh) * 2009-05-08 2011-04-06 上海汽车集团股份有限公司 发动机气门连续可变驱动机构

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