EP1149988A2 - Verfahren und Vorrichtung für einen zweistufigen Nockenprofilwechsel - Google Patents

Verfahren und Vorrichtung für einen zweistufigen Nockenprofilwechsel Download PDF

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Publication number
EP1149988A2
EP1149988A2 EP01201493A EP01201493A EP1149988A2 EP 1149988 A2 EP1149988 A2 EP 1149988A2 EP 01201493 A EP01201493 A EP 01201493A EP 01201493 A EP01201493 A EP 01201493A EP 1149988 A2 EP1149988 A2 EP 1149988A2
Authority
EP
European Patent Office
Prior art keywords
shaft
lift
side member
cam lobe
bearing
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.)
Granted
Application number
EP01201493A
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English (en)
French (fr)
Other versions
EP1149988A3 (de
EP1149988B1 (de
Inventor
Mark. J. Spath
Hermes A. Fernandez
Nick J. Hendriksma
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
Publication of EP1149988A2 publication Critical patent/EP1149988A2/de
Publication of EP1149988A3 publication Critical patent/EP1149988A3/de
Application granted granted Critical
Publication of EP1149988B1 publication Critical patent/EP1149988B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • F01L1/267—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder with means for varying the timing or the lift of the 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
    • F01L1/18—Rocking arms or levers
    • F01L1/185—Overhead end-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
    • F01L13/0015—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
    • F01L13/0036—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 the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
    • 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
    • F01L2001/186—Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison
    • 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 relates generally to a method and apparatus for cam profile mode switching. More particularly, the apparatus of the present invention relates to a two-step roller finger follower for cam profile mode switching.
  • Vehicle manufacturers have different goals for various vehicle platforms or models.
  • the primary goal for one particular model may be to provide relatively high fuel economy, and for another model the goal may be to provide relatively high engine power output.
  • the goal of providing relatively high fuel economy can be accomplished through the use of a cam having a relatively low lift and short duration lift profile, whereas high engine power is provided by the use of a cam having a higher lift and longer duration profile.
  • the goals of high fuel economy and high power often involve conflicting design choices, and an acceptable tradeoff must be reached between the two competing goals for a particular vehicle model.
  • high lift long duration output cams are designed to provide high power output at high engine operating speeds.
  • high lift long duration output cams typically result in decreased engine idle quality and reduced low speed torque and drivability due to reduced air mass charged into the cylinder which is associated with the relatively long overlap duration of the opening and closing of the engine valves.
  • cams which are designed to increase volumetric efficiency at high engine operating speeds typically reduce volumetric efficiency at lower engine operating speeds.
  • a high lift long duration cam improves volumetric efficiency at high engine operating speeds by increasing the flow rate past the valve.
  • the longer duration lift provides more time in which to fill the cylinder with air.
  • the relatively late closing of the intake valve associated with a long duration cam takes advantage of the inertial effects of the intake charge to further increase high speed volumetric efficiency.
  • a low lift short duration cam is best suited for low engine operating speeds due to improved intake charge velocity, which improves volumetric efficiency.
  • the increased intake charge velocity also creates a more homogenous mixture that improves combustion by increasing either swirl or tumble.
  • the shorter duration cam reduces valve overlap and thereby improves volumetric efficiency at low engine operating speeds.
  • the relatively early closing of the intake valves associated with such low lift short duration cams further improves volumetric efficiency at low engine operating speeds.
  • the present invention provides a method and apparatus for two-step cam profile mode switching.
  • the invention comprises, in one form thereof, a two-step roller finger follower including an elongate body having a first side member and a second side member. A first end and a second end interconnect the first and second side members. The first and second side member define first and second pin orifices, respectively.
  • a center roller is disposed between the first and second side members. The center roller defines a shaft orifice therethrough.
  • a shaft extends through the shaft orifice.
  • a first shaft end is disposed proximate the first side member, and the second shaft end is disposed proximate the second side member.
  • the second shaft end defines a shaft bore therein.
  • the first shaft end defines a pin chamber therein.
  • the shaft bore is substantially concentric with and intersects the pin chamber.
  • a locking pin assembly is disposed partially within the shaft bore, the pin chamber and at least one of the pin orifices.
  • the locking pin assembly has a first position wherein the shaft is decoupled from the body and a second position wherein the shaft is coupled to the body, and is switchable between the first and second positions.
  • An advantage of the present invention is that the two-step roller finger follower for cam profile mode switching enables a high lift/long duration and a low lift/short duration activation of an associated valve while occupying substantially the same amount/volume of space as is occupied by a conventional roller finger follower.
  • Another advantage of the present invention is that very few component parts are added relative to a conventional roller finger follower.
  • a further advantage of the present invention is that the two-step roller finger follower for cam profile mode switching improves engine idle quality and driveability during part-load engine operating conditions by enabling a low lift/short duration activation of an associated valve, and improves volumetric efficiency and power at high engine operating speeds.
  • a still further advantage of the present invention is that the two-step roller finger follower for cam profile mode switching employs roller bearings for reduced friction and increased fuel economy for both high-lift and low-lift motion.
  • the two-step roller finger follower for cam profile mode switching (two-step RFF) of the present invention is switchable between a first mode and a second mode.
  • the two-step RFF transfers rotary motion of at least one outer, such as, for example, a low lift and short duration, cam lobe of a camshaft of an internal combustion engine to pivotal movement of the body of the two-step RFF to thereby actuate an associated valve of the engine in accordance with the lift profile of the at least one outer cam lobe.
  • the two-step RFF transfers rotary motion of a center, such as, for example, a high-lift and long duration, cam lobe of the camshaft to pivotal movement of the two-step RFF body to thereby actuate an associated valve in accordance with the lift profile of the center cam lobe.
  • a center such as, for example, a high-lift and long duration
  • two-step RFF 10 is installed in internal combustion engine 12, and engages camshaft 32 of engine 12.
  • One end of two-step RFF 10 engages valve 14 of engine 12, the other end engages a stem 16 of lash adjuster 18.
  • two-step RFF 10 includes body 20, locking pin assembly 22, lost motion springs 24a and 24b, central roller 26, bearings 28a, 28b, and hollow shaft 30 (Fig. 3).
  • Body 20 includes first end 34, second end 36, elongate first side member 38, and elongate second side member 40.
  • First end 34 includes valve stem pallet 42, which receives valve 14 of engine 12.
  • Second end 36 defines a hemispherical lash adjuster socket 44 (see Fig. 1), which receives lash adjuster stem 16 of engine 12.
  • Each of first side member 38 and second side member 40 extend between and interconnect first end 34 and second end 36.
  • Each of first side member 38 and second side member 40 include a respective bearing boss 46a, 46b (Fig. 3) which support a corresponding one of bearings 28a, 28b.
  • Body 20 is constructed of, for example, steel, carbon steel, or alloy steel.
  • first side member 38 and second side member 40 define a respective pin orifice 50, 52 therethrough.
  • pin orifices 50, 52 is concentric with center axis A.
  • First side member 38 and second side member 40 each include an inside surface 38a, 40a, respectively.
  • Roller aperture 54 is defined between inside surfaces 38a, 40a, and intermediate first end 34 and second end 36.
  • Inside surface 38a defines slot 56, which is disposed adjacent roller aperture 54.
  • Inside surface 40a defines slot 58, which is disposed adjacent roller aperture 54 and is transversely opposite slot 56.
  • Each of slots 56, 58 extend from a respective top surface (not referenced) a to a corresponding bottom surface (not referenced) of first and second side members 38, 40.
  • first side member 38 includes bearing boss 46a. Boss 46a surrounds pin orifice 50.
  • Retaining clip 64 defines retaining clip orifice 64a, and is secured, such as, for example, by rolling, to boss 46a such that retaining clip orifice 64a is substantially concentric with pin orifice 50.
  • second side member 40 includes bearing boss 46b which surrounds pin orifice 52.
  • Retaining clip 66 defines retaining clip orifice 66a, and is secured, such as, for example, by rolling, to boss 46b such that retaining clip orifice 66a is substantially concentric with pin orifice 52.
  • Locking pin assembly 22 as best shown in Figs. 3 and 4, includes locking pin 74, button 76, and pin spring 78.
  • Locking pin 74 includes stem portion 74a and head 74b.
  • Locking pin 74 is slidably disposed at least partially within shaft 30, as will be described more particularly hereinafter.
  • Button 76 is a substantially cylindrical member having shoulder 76a.
  • Button 76 is slidably disposed at least partially within pin orifice 50 in first side member 38 and is selectively received within shaft 30.
  • Pin spring 78 is disposed within shaft 30 in association with locking pin 74, and biases locking pin assembly 22 into the first, such as, for example, low-lift, mode.
  • Each of locking pin 74 and button 76 are constructed of, for example, steel, carbon steel, or alloy steel.
  • Pin spring 78 is constructed of, for example, music or piano wire, and configured as, for example, a coil spring. As will be more particularly described hereinafter, locking pin assembly 22 is operable to switch two-step RFF 10 between the first mode and the second mode.
  • Lost motion springs 24a and 24b are coiled around opposite ends of shaft 30. More particularly, lost motion spring 24a is coiled around the end of shaft 30 proximate second side member 38 and lost motion spring 24b is coiled around the other end of shaft 30 proximate first side member 40. Each of lost motion springs 24a and 24b extend radially from shaft 30 to abuttingly engage each of first end 34 and second end 36 of body 12. Each of lost motion springs 24a and 24b apply a spring force or load upon hollow shaft 30 to thereby bias hollow shaft 30 in the direction of the top surfaces (not referenced) of body 12, i.e., in a direction toward cam shaft 32 (Fig. 1). Lost motion springs 24a and 24b are configured as, for example, torsion springs, and are constructed of, for example, chrome silicon.
  • Central roller 26 is a substantially cylindrical hollow member which includes outside surface 26a and central bore or orifice 26b.
  • Elongate hollow shaft 30 extends through central orifice 26b, with the ends thereof disposed adjacent a corresponding one of first side member 38 and second side member 40.
  • a plurality of needle bearings 80 are disposed intermediate central orifice 26b of roller 26 and hollow shaft 30.
  • roller 26 is free to rotate about hollow shaft 30 in an essentially friction free manner.
  • Outside surface 26a of roller 26 is configured to engage central, such as, for example, high-lift, cam lobe 32a (Figs. 1 and 5) of camshaft 32.
  • Roller 26 is constructed of, for example, steel, carbon steel, or alloy steel.
  • Shaft 30 is an elongate substantially cylindrical hollow member extending transversely between first side member 38 and second side member 40.
  • Shaft 30 has first end 30a disposed in slot 56 and second end 30b disposed within slot 58.
  • Shaft 30 has a predetermined diameter to enable it to freely reciprocate within each of slots 56, 58 in a generally vertical direction while preventing any binding and minimizing movement of shaft 30 toward and away from either of first end 34 and second end 36.
  • Shaft 30 defines shaft bore 82 and pin chamber 84.
  • Each of shaft bore 82 and pin chamber 84 are substantially concentric relative to central axis A.
  • Shaft bore 82 and pin chamber 84 are contiguous with and intersect each other at shoulder 82b.
  • Stem portion 74a of locking pin 74 is slidably disposed at least partially within shaft bore 82 and pin chamber 84, and is selectively received within pin orifice 52.
  • Pin spring 78 is disposed in abutting engagement with each of head 74b of locking pin 74 and shoulder 82b of shaft bore 82. Pin spring 78 pre-loads or biases locking pin assembly 22 toward an unlocked position to thereby place two-step RFF 10 into a first, or low-lift, mode.
  • Button 76 is slidingly disposed at least partially within first pin orifice 50 and is selectively received within pin chamber 84.
  • Shaft 28 is constructed of, for example, steel, carbon steel, or alloy steel.
  • locking pin assembly 22 is operable to switch two-step RFF 10 between the first mode and the second mode.
  • Locking pin assembly 22 is now described in the first, or low-lift, mode as shown in and with reference to Fig. 3.
  • first mode locking pin assembly 22 decouples shaft 30 from body 20.
  • button 76 is disposed only within pin orifice 50 of first side member 36. A portion of button 76 extends from pin orifice 50 on the side of first side member 38 that is opposite inside surface 38a thereof.
  • locking pin 74 is disposed only within shaft bore 82 and pin chamber 84 of shaft 30.
  • valve 14 is not actuated in accordance with the lift profile of center cam lobe 32a. Rather, body 20 is pivoted and valve 14 is actuated according to the lift profile of outside cam lobes 32b, 32c, which engage bearings 28a, 28b, respectively.
  • locking pin assembly 22 couples shaft 30 to body 20 to thereby transfer rotary motion of center cam lobe 32a (Figs. 1 and 5) to vertical motion of valve 14 (Fig. 1).
  • stem portion 74a of locking pin 74 is disposed within each of pin orifice 52 in second side member 40, shaft bore 82 and pin chamber 84, thereby coupling shaft 30 to second side member 40.
  • Button 76 in the second mode, is disposed within each of pin chamber 84 and pin orifice 50 of first side member 38. Thus, button 76 couples shaft 30 to first side member 38.
  • shaft 30 is coupled to each of first side member 38 and second side member 40, and thus rotary motion of center cam lobe 32a is transferred by roller 26 to shaft 30.
  • the coupling of shaft 30 to each of first and second side members 38, 40, respectively, by locking pin assembly 22 transfers the rotary motion of center cam lobe 32a to pivotal movement of body 20 about lash adjuster 18.
  • valve 14 is actuated in accordance with the lift profile, such as, for example, a high and long duration lift profile, of center cam lobe 32a.
  • camshaft 32 has central axis S and includes center cam lobe 32a.
  • Center cam lobe 32a is configured, such as, for example, a high-lift cam lobe.
  • Outside cam lobes 32b, 32c Disposed on each side of and adjacent to center cam lobe 32a are outside cam lobes 32b, 32c, which are configured as, for example, low-lift cam lobes relative to center cam lobe 32a.
  • Outside cam lobes 32b, 32c and center cam lobe 32a are disposed in a predetermined angular relation relative to each other, and relative to central axis S of camshaft 32.
  • Outside cam lobes 32b, 32c have a lift profile which is less in magnitude and duration than the lift profile of center cam lobe 32a.
  • two-step RFF 10 is disposed such that outer surface 26a of roller 26 engages center cam lobe 32a, valve stem pallet 42 receives the end of a valve stem (not referenced) of valve 14, and lash adjuster socket 44 engages lash adjuster stem 16.
  • locking pin assembly 22 decouples shaft 30 from body 20.
  • Bearings 28a, 28b engage outside lobes 32b, 32c of camshaft 32, which pivot body 20 and thereby actuate valve 14 according to the lift profile of outside lobes 32b, 32c.
  • Locking pin assembly 22, and thus two-step RFF 10, is selectively placed into and switched between the first and second modes by a control device (not shown), such as, for example, a hydraulic actuating piston (not shown) which is mounted into a bore on the cam bearing tower (not shown) adjacent two-step RFF 10.
  • the actuating piston is in axial alignment with button 76 of locking pin assembly 22.
  • Pressurized fluid such as, for example, oil, is selectively fed into and removed from the bore of the actuating piston to thereby cause the actuating piston to translate outward or retract inward in a direction toward and away from button 76.
  • Locking pin assembly 22, and thus two-step RFF 10, is placed into the second/high-lift mode (Fig. 4), wherein shaft 30 is coupled to body 20, by translating the actuating piston outward and into engagement with button 76.
  • the actuating piston overcomes the force of pin spring 78 and slidingly displaces button 76 axially in a direction toward second side member 40.
  • the actuating piston displaces at least a portion of button 76 from within pin orifice 50 and into pin chamber 84 of shaft 30.
  • the displacement of button 76 into pin chamber 84 results in a corresponding displacement of stem portion 74a of locking pin 74 out of shaft bore 82 and into pin orifice 52 of second side member 40.
  • shaft 30 is coupled to each of first side member 38 and second side member 40.
  • the actuating piston axially displaces button 76 into pin orifice 50 a predetermined distance in a direction toward second side member 40.
  • outside cam lobes 32a, 32b have substantially no operable effect upon the operation of valve 14.
  • outside cam lobes 32a, 32b operate to open or lift valve 14 a predetermined small amount and duration.
  • the slight activation of valve 14 allows a relatively small amount of air to enter the associated cylinder of engine 12, thereby ensuring a higher intake velocity, a more complete combustion process, and thereby improve driveability under low load conditions and engine idle quality.
  • Locking pin assembly 22, and thus two-step RFF 10, is placed into the first/low-lift mode by retracting the actuating piston inward thereby disengaging the actuating piston from contact with button 76.
  • pin spring 78 is disposed, or compressed, between shoulder 82b of shaft bore 82 and head 74b of locking pin 74.
  • Pin spring 78 exerts an axially directed force against head 74b to thereby pre-load or normally bias locking pin assembly 22 into the first/low-lift mode.
  • Pin spring 78 slidingly displaces locking pin 74 axially in the direction of first side member 38 and into abutting engagement with button 76. The displacement of locking pin 74 results in a corresponding displacement of button 76 in the same direction.
  • Button 76 is thus displaced until shoulder 76a of button 76 contacts retaining clip 64.
  • the engagement of shoulder 76a by retaining clip 64 limits the axial displacement of button 76 by pin spring 78, and thereby establishes the first/low-lift mode positions of locking pin 74 and button 76 relative to body 20.
  • the interface of locking pin 74 and button 76 is disposed within slot 56 of first side member 38. This axial position permits locking pin 74 to move relative to or slide over button 76 within slot 56 in a direction toward and away from camshaft 32.
  • the end of locking pin 74 proximate second side member 40 is disposed within slot 58 of second side member 40. This axial position permits locking pin 74 to move or slide within slot 58 in a direction toward and away from camshaft 32.
  • shaft 30 is likewise enabled to move or slide within each of slots 56, 58 in a direction toward and away from camshaft 32.
  • lost motion springs 24a and 24b absorb the motion of shaft 30 as roller 26 engages and follows the lift profile of center cam lobe 32a, and ensure that roller 26 remains in contact therewith. Slots 56, 58 retain and guide the movement of shaft 30 as center cam lobe 32a rotates and displaces shaft 30.
  • lost motion springs 24a and 24b are coiled around respective ends of shaft 30 proximate to second side member 40 and first side member 38, respectively. Lost motion springs 24a and 24b apply a spring force or load upon shaft 30 to thereby bias shaft 30 in the direction of camshaft 32. As center cam lobe 32a is rotated onto the nose thereof, a downward force is exerted upon shaft 30.
  • lost motion springs 24a and 24b upon shaft 28 is overcome by the force exerted by center cam lobe 32a through roller 26 upon shaft 30, thereby resulting in shaft 30 being slidingly displaced downward within slots 56, 58 in a direction away from camshaft 32.
  • the downward motion of shaft 30 is absorbed by lost motion springs 24a and 24b.
  • center cam lobe 32a is rotated onto the base circle thereof, the load exerted upon shaft 30 by lost motion springs 24a and 24b maintains roller 26 in contact with center cam lobe 32a.
  • lost motion springs 24a, 24b bias shaft 30 upward within slots 56, 58 in the direction of camshaft 32 and into a position which enables the return of locking pin assembly 22 into the decoupled or low-lift first mode position.
  • pin orifices 50 and 52 registration of pin orifices 50 and 52 relative to shaft bore 82 and pin chamber 84 is conjunctively accomplished by roller 26, bearings 28a, 28b, center cam lobe 32a, outer cam lobes 32b, 32c, and lost motion springs 24a, 24b.
  • center cam lobe 32a When center cam lobe 32a is at its base circle or lowest lift profile position, lost motion springs 24a and 24b bias shaft 30 toward camshaft 32, and maintain outer surface 26a of roller 26 engaged with center cam lobe 32a.
  • roller 26 and shaft 30 is located by the base circle of center cam lobe 32a, while the position of body 20 is located by the base circle of outer cam lobes 32b and 32c engaging bearings 28b, 28a, respectively, such that shaft bore 82 and pin chamber 84 are axially aligned with pin orifices 50, 52.
  • the axial alignment of shaft bore 82 and pin chamber 84 with pin orifices 50, 52 brings stem portion 74a of locking pin 74 into axial alignment with pin orifice 52 and head 74b into axial alignment with pin orifice 50 having button 76 disposed therein.
  • Pin spring 78 then displaces locking pin 74 in a direction toward first side member 38.
  • Pin spring 78 continues to displace locking pin 74 in a direction toward first side member 38 such that head 74b of locking pin 74 engages and displaces button 76.
  • button 76 is displaced from disposition within pin chamber 84. The displacement of locking pin 74 and button 76 continues until shoulder 76a of locking pin 76 engages retaining clip 64.
  • two-step RFF 10 in conjunction with outside lobes 32b, 32c of camshaft 32 operate to activate valve 14 in accordance with the lift profile of outside lobes 32b, 32c.
  • valve 14 is opened or lifted a predetermined and relatively slight amount for a relatively slight duration relative to the amount and duration of lift imparted to valve 14 with two-step RFF 10 in the second/high-lift mode.
  • two step RFF 10 in conjunction with center cam lobe 32a of camshaft 32 operate to activate valve 14 in accordance with the lift profile of center cam lobe 32a.
  • center cam lobe 32a With, for example, a relatively high and long duration lift profile, valve 15 is opened or lifted a predetermined and relatively large amount for a relatively long duration relative to the amount and duration of lift imparted to valve 15 with two-step RFF 10 ni the first/low-lift mode.
  • the breathing capability and the power capability of the engine under high-engine operating speed are improved.
  • valve 14 is actuated at substantially the same time and at a predetermined angular position of camshaft 32, regardless of whether roller finger follower 10 is in the first/low-lift or second/high-lift mode.
  • outer or low-lift cam lobes 32b, 32c can be shifted or offset relative to central axis S and relative to center or high-lift cam lobe 32a. Offsetting the angular position of low-lift cam lobes 32b, 32c relative to central axis S and relative to high-lift cam lobe 32a changes the angular position of camshaft 32 at which valve 14 is opened with two-step RFF 10 in the second/high-lift mode relative to the angular position of camshaft 32 at which valve 14 is opened with roller finger follower 10 in the first/low-lift mode.
  • the angular position of outer or low-lift cam lobes 32b, 32c relative to central axis S can be offset, such as, for example, by positive (i.e., in the same direction as the rotation of camshaft 32) fifteen degrees relative to the angular position of center or high-lift cam lobe 32a to thereby phase the opening or actuation of valve 14.
  • positive i.e., in the same direction as the rotation of camshaft 32
  • the peak of outer or low-lift cam lobes 32b, 32c rotationally precede the peak of center or high-lift cam lobe 32a by fifteen degrees.
  • valve 14 can be changed and/or adjusted by selecting the predetermined angular relationship of outer/low-lift cam lobes 32b, 32c relative to center or high-lift cam lobe 32a to thereby change opening and closing timing of valve 14, as well as valve overlap, when two-step RFF 10 is in the first/low-lift mode.
  • This control over valve lift, valve lift timing, valve opening duration and valve overlap can be used to optimize high speed power while maintaining low speed torque, driveability, and engine idle quality.
  • the first/low-lift mode is the default position and the default operating mode of locking pin assembly 22 and two-step RFF 10, respectively.
  • two-step RFF 10 can be alternately configured, such as, for example, to have the second or high-lift mode as the default operating position/mode.
  • bearings 28a, 28b are secured to body 20 of two-step RFF 10 to engage outside cam lobes 32b, 32c in a relatively frictionless manner.
  • two-step RFF 10 can be alternately configured, such as, for example, with slider pads disposed on or integral with the body thereof, to engage outside cam lobes 32b, 32c.
  • retaining clips 64 and 66 are secured, such as, for example, by rolling, to a respective boss 46a, 46b.
  • two-step RFF 10 may be alternately configured, such as, for example, as having a retaining clip formed integrally with the boss or body, or attached by alternate means, such as, for example, staking or welding.
  • each of slots 56 and 58 extend from the bottom surface (not referenced) of first and second side member 38, 40, respectively, to a top surface (not referenced) thereof.
  • the slots may be alternately configured, such as, for example, extending only partially toward one or both of the the top and bottom surfaces of the roller finger follower body.

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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)
EP01201493A 2000-04-26 2001-04-25 Verfahren und Vorrichtung für einen zweistufigen Nockenprofilwechsel Expired - Lifetime EP1149988B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US19971600P 2000-04-26 2000-04-26
US199716P 2000-04-26

Publications (3)

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EP1149988A2 true EP1149988A2 (de) 2001-10-31
EP1149988A3 EP1149988A3 (de) 2001-11-14
EP1149988B1 EP1149988B1 (de) 2005-11-02

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EP01201493A Expired - Lifetime EP1149988B1 (de) 2000-04-26 2001-04-25 Verfahren und Vorrichtung für einen zweistufigen Nockenprofilwechsel

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DE (1) DE60114501T2 (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003042507A1 (de) * 2001-11-14 2003-05-22 Ina-Schaeffler Kg Schlepphebel eines ventiltriebs einer brennkraftmaschine
WO2003042510A1 (de) * 2001-11-14 2003-05-22 Ina-Schaeffler Kg Schlepphebel eines ventiltriebs einer brennkraftmaschine
EP1318278A2 (de) * 2001-12-04 2003-06-11 Delphi Technologies, Inc. Kipphebel mit Walzlager
WO2007035673A2 (en) 2005-09-16 2007-03-29 Timken Us Corporation Switching finger follower assembly
EP2063074A1 (de) * 2007-11-21 2009-05-27 Delphi Technologies, Inc. Lagerauslegung für einen Rollenschlepphebel
US7546822B2 (en) 2004-03-03 2009-06-16 Timken Us Corporation Switching finger follower assembly
WO2011113702A1 (de) * 2010-03-18 2011-09-22 Schaeffler Technologies Gmbh & Co. Kg Schaltbarer hebel für einen ventiltrieb einer brennkraftmaschine
WO2013156610A1 (en) * 2012-04-19 2013-10-24 Eaton Srl A rocker arm
US10400639B2 (en) 2015-11-20 2019-09-03 Man Truck & Bus Ag Variable valve train with a rocker arm

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RO132154A2 (ro) 2016-03-21 2017-09-29 Schaeffler Technologies AG & Co.KG Aranjament de comutare cu came

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003042510A1 (de) * 2001-11-14 2003-05-22 Ina-Schaeffler Kg Schlepphebel eines ventiltriebs einer brennkraftmaschine
WO2003042507A1 (de) * 2001-11-14 2003-05-22 Ina-Schaeffler Kg Schlepphebel eines ventiltriebs einer brennkraftmaschine
EP1318278A2 (de) * 2001-12-04 2003-06-11 Delphi Technologies, Inc. Kipphebel mit Walzlager
US7546822B2 (en) 2004-03-03 2009-06-16 Timken Us Corporation Switching finger follower assembly
WO2007035673A2 (en) 2005-09-16 2007-03-29 Timken Us Corporation Switching finger follower assembly
WO2007035673A3 (en) * 2005-09-16 2007-05-24 Timken Us Corp Switching finger follower assembly
EP2305966A1 (de) * 2005-09-16 2011-04-06 Koyo Bearings USA, LLC Schaltschlepphebelanordnung
EP2063074A1 (de) * 2007-11-21 2009-05-27 Delphi Technologies, Inc. Lagerauslegung für einen Rollenschlepphebel
WO2011113702A1 (de) * 2010-03-18 2011-09-22 Schaeffler Technologies Gmbh & Co. Kg Schaltbarer hebel für einen ventiltrieb einer brennkraftmaschine
US8794205B2 (en) 2010-03-18 2014-08-05 Schaeffler Technologies Gmbh & Co. Kg Switchable lever for a valve drive of an internal combustion engine
WO2013156610A1 (en) * 2012-04-19 2013-10-24 Eaton Srl A rocker arm
US9470116B2 (en) 2012-04-19 2016-10-18 Eaton Srl Rocker arm
US10196943B2 (en) 2012-04-19 2019-02-05 Eaton Intelligent Power Limited Valve train assembly
US10400639B2 (en) 2015-11-20 2019-09-03 Man Truck & Bus Ag Variable valve train with a rocker arm

Also Published As

Publication number Publication date
EP1149988A3 (de) 2001-11-14
DE60114501D1 (de) 2005-12-08
EP1149988B1 (de) 2005-11-02
DE60114501T2 (de) 2006-04-27

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