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
  • F01L1/265—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 peculiar to machines or engines with three or more intake valves per cylinder
• • 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
• • 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
• • 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
  • F01L2303/00—Manufacturing of components used in valve arrangements
  • F01L2303/01—Tools for producing, mounting or adjusting, e.g. some part of the distribution
• • 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
• • 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
  • F01L2800/00—Methods of operation using a variable valve timing mechanism
  • F01L2800/13—Throttleless

Definitions

• Our invention relates to varying the valve stroke of an internal combustion piston engine, to allow regulating the output of an internal combustion Otto engine.
• One of the factors causing a loss is the throttle valve used for regulating the output of the Otto engine in the intake pipe, which - as a result of the resistance caused by the same - limits the volume of air introduced into the combustion space of the engine.
• the regulation function can also be implemented by altering the opening period and lift height of the intake valve, which results in much lower losses than in the case of using the approach above.
• the valve stem supports a single-arm rocker with a roller in the centre, pressed by a guiding curve at the end of a rocker lever, as a result of its tangential displacement vis-a-vis the roller, which said displacement is caused by the cam of the camshaft. It is an important characteristic of the mechanism that the single-arm rocker and its actuating rocker lever with the guiding curve include an angle of almost 90 degrees and the path of lifting the cam is longer than the path of lifting the valve. As a result, the applicability of this approach is limited.
• the object of our invention is a mechanism for varying the valve stroke of an internal combustion piston engine, to any value between zero stroke and nominal stroke, which mechanism has a valve actuating camshaft, the cam of which is constantly in contact with the contact surface of a single-arm rocker lever, which is pinned at one end by using a stationary pin, and at the other rotating end a rocker pivot is fitted which has a parallel axis with a stationary support that allows rotation, preferably a pin, which holds one end of a lifting rocker lever, and on the other end there is a pressure surface resting on the stem of the actuated valve.
• the lifting rocker lever is fitted with a support surface for rotating around the rocker pivot, and it is constantly in contact with the guiding curve of a guiding block pinned in a movable way.
• the reset (basic) position of the said guiding block is assigned to the zero stroke position of the valve and the other extreme position to the nominal stroke position. To any position in-between, the midway stroke is assigned, and the guiding block is linked to the engine control/regulator actuating member which controls the valve lifting.
• the geometrical axis of the rotary rocker pivot of the lifting rocker lever, the centreline of its pressure surface and the centreline of its support surface are at the apexes of an acute-angled triangle
• the support surface of the lifting rocker lever is represented by the outer surface of a pinned roller
• the contact surface of the single-arm rocker lever is represented by the outer surface of a pinned roller.
• the guiding block runs in a straight guide in a plane normal to the camshaft, and the straight guide is preferably a cylindrical pin fitted with a member that secures it against turning, the guiding block is fitted with a rack engaged by the gear of a valve lift control member, and the axis of the said gear is preferably parallel with the camshaft.
• the single-arm rocker lever and the pin of the guiding block are arranged around the camshaft, in fact they preferably include an angle of 30 degrees in a plane normal to the camshaft, and between their intersection point and the camshaft is the lifting rocker lever, which has a loading hairpin spring to make sure that it rests on the guiding curve of the guiding block.
• two neighbouring valves have a separate lifting rocker lever each, with a joint pivot pin holding one single- arm rocker lever, and the single-arm rocker lever is in contact with a single cam.
• two neighbouring valves have a separate lifting rocker lever each, with a separate single-arm rocker lever fitted for each. Each single-arm rocker lever is in contact with a separate cam, and the single-arm rocker levers each have a separate guiding block, in the given case fitted with a different guiding curve.
• the two extreme valves have a separate lifting rocker lever, with a single- arm rocker lever each, in contact with a separate cam each, and the two single- arm rocker levers have a joint rocker pivot pinned in a way allowing rotation in the bore of the single-arm rocker lever, the lifting rocker levers are fixed so that they rotate jointly on their rotary rocker pivots, and in the section of the rocker pivot between the two single-arm rocker levers there is a third lifting rocker lever fixed so that they rotate jointly, and having a pressure surface resting on the stem of the valve in the middle.
• the guiding curve of the guiding block has a starting section parallel with the guiding pin, to which a zero valve lift is assigned, the initial section is attached to a first lifting section, which is preferably straight and includes an angle of some degrees with the guiding pin, and the first lifting section adjoins a second lifting section, which is arc-shaped, and the second section adjoins a third lifting section, which is preferably straight and includes an angle of approx. 60 degrees with the guiding pin.
• the guiding block has a curved guiding surface resting on a guide of identical curve, the arc is of concave shape when viewed from the rocker pivot, the guide is fixed in a stationary way, the plane normal to the generatrix of the curved guiding surface is advisably also normal to the geometrical axis of the camshaft, along the curved guiding surface, there is a movement surface advisably including the line normal to the guiding surface.
• This movement surface is on the pin of the guiding block, with which an eccentric arranged on a guiding shaft and arranged as an engine control/regulator actuating element to control valve lift is in contact.
• the eccentric located on the engine control/regulator eccentric shaft is between a movement surface on each of two pins fitted on the guiding block, advisably without play and the guide of the guiding block is arranged as a two-prong yoke fitted with a guiding surface each, and the opening of the yoke head is arranged in a way suitable for receiving the protective pipe of the spark plug.
• the guiding surface on the two-prong yoke is arranged on the valve side of the yoke prong, as a cylindrical surface section,
• the stems of the two-prong yoke are located with their guiding surfaces.
• a spring support surface is arranged on the lug receiving the single-arm rocker lever rocker pivot on the side opposite the guiding block, a pressure spring is supported by the spring support surface, a hydraulic lash adjustor is fitted into the lifting rocker lever, and the said adjustor has a pressure surface supported by the end of the valve stem.
• the bearing members of the yoke prongs of the guiding block there are bores, arranged on the.stationary pin of the single arm rocker.lever.
• Fig. 1 is an axonometric diagram of a mechanism featuring as the first embodiment example, which is suitable for actuating three intake valves,
• Fig. 2 is the mechanism in zero stroke valve lift position
• Fig. 3 is the mechanism in a valve lift position
• Fig. 4 is the arrangement of the valve actuating lifting levers
• Fig. 5 is an axonometric diagram of a mechanism featuring as the second embodiment example, which is suitable for actuating two intake valves,
• Fig. 6 is a different view of the mechanism in Fig. 5,
• Fig. 7 is an axonometric diagram of the mechanism as a third embodiment example, which is suitable for actuating two intake valves, having a third type of valve lift regulating guiding block,
• Fig. 8 is an axonometric diagram of the valve lift regulating guiding block of the mechanism in Fig. 7.
• the cylinder of the internal combustion piston engine not shown has three intake valves, the exhaust valves and their actuating mechanism are not shown, the valve arrangement of the cylinder head and its valve actuating mechanism is of a DOHC design.
• the engine is of the Otto type, and its spark plug is in the centreline of the cylinder, surrounded by a protective pipe, the receiving cylinder head is not shown.
• the mechanism 1 actuates the valves 2 and 3, which have valve stems 4 and valve stem ends 5, they are actuated by shifting along the geometrical axis of the valve stem 4, and as a result of the mechanism 1 the rate of shift can be adjusted to any extent between zero and the nominal (maximum) value.
• the valve stem end 5 supports the pressure surface 7 of the lifting rocker lever 6 of the mechanism 1 , and the shape of the said pressure surface is identical with a small detail of the cylinder surface, the centreline 8 of the pressure surface 7 is parallel with the axis of the rocker pivot 9 going through the bore 10 of the lifting rocker lever 6.
• the rocker pivot 9 is pinned in a way allowing rotation in the bore 20 of the single-arm rocker lever 19, and using its bore 22, it is pinned in a way allowing rotation on the stationary pin 23 fixed in the cylinder head casting not shown.
• the geometrical axis of the valve stem 4 of the two identical position valves 2 is situated near the geometrical axis of the camshaft 27.
• the pressure lever 11 of the lifting rocker lever 6 and the single-arm rocker lever 19 are basically one behind the other as a result of which their space requirement is minimal when measured in the direction of the geometrical axis of the valve stem 4.
• the arrangement of the spark plug of the cylinder head not shown is central, and uniaxially with it is the protective pipe 47 in the immediate vicinity of which is the rocker pivot 9.
• the lifting rocker lever 6 also has the support lever 12, which in this embodiment example includes an angle of approx. 120 degrees, the support lever 12 is roughly parallel with the valve stem 4 and it faces the camshaft 27 in the zero valve stroke position of the mechanism 1.
• the support surface 13 and the centreline 14 of the support lever 12 are represented by the outer surface 16 of the roller 15 and its generatrix, the roller 15 runs on pin 17, which is fixed in the bore 18 of the support lever 12.
• the geometrical axis of the rotary rocker pivot 9 of the lifting rocker lever 6, the centreline 8 of the pressure surface 7 supported by the valve stem 4 and the centreline of the support surface 13 are located at the apexes of an acute-angled triangle.
• the roller 15 of the support lever 12 is supported by the guiding curve 35 of the guiding block 32, which is a surface of straight generatrix.
• the guiding block 32 can be moved along a straight guide represented by the guiding pin 41, on which the guiding block 32 is supported with its bore 33, and the said guiding block has a protrusion 34 including an angle of approx. 30 degrees with the guiding pin 41.
• the guiding curve 35 consists of several sections, and roughly parallel with the guiding pin 41 is the starting section 36, to which the first section 37 is connected, this includes an angle of 1-2 degrees with the guiding pin 41, the second section 38 is adjoined to the first section 37, and the former has an arched shape, but its radius 40 is longer than the radius of the roller 15, the second section 38 adjoins the third section 39, which is preferably straight lined and includes an angle of approx. 60 degrees with the guiding pin 41, and it is arranged on protrusion 34 of the guiding block 32.
• the guiding block 32 On the side opposite the guiding curve 35, the guiding block 32 has a rack 44 on the side 43 opposite the guiding curve, and this rack is engaged by the pinion 45.
• the pinion 45 which is shown as a full gear in the figure, is fixed in a stationary way on the guiding shaft 46, pinned in a way allowing rotation in the cylinder head casting not shown.
• the guiding block 32 is secured against turning, provided that its protrusion 34 has in its central plane the longitudinal axis of the guiding pin 41 and the central plane of the rack 44.
• the central lifting rocker lever 54 is not fitted with a support lever like the two extreme position lifting rocker levers 6, which have support levers 12.
• a guiding block 34 fitted with a guiding curve 35 is assigned separately, which have separately a guiding pin 41 fixed in the cylinder head casting not shown. Between guiding pins 41 is the protective pipe 47.
• a web 42 connects and combines into a solid member the two guiding blocks 34, on web 42 is the rack 43, which is engaged by the pinion 44 or gear as shown fixed to the guiding shaft 46.
• the turning of the guiding shaft 46 varies the stroke of lifting the valve 2.
• an electric drive motor not shown is fitted.
• the mechanism 1 is suitable for actuating both intake and exhaust valves. The mechanism 1 operates as follows:
• the mechanism 1 In the position shown in Fig. 1 , the mechanism 1 is in a zero valve lift position. In spite of that, the mechanism 1 is ready to move, and when the camshaft 27 turns, the cam 28 actuates the roller 25, turning the single-arm rocker lever 19 around the stationary pin 23, and thereby the rocker pivot 9 must also move along an arc, as a result of which the lifting rocker lever 6 must turn around the rocker pivot 9.
• the extent of turn is determined by the guiding curve 35 of the guiding block 32, and a zero valve lift is associated with the starting section 36 of the guiding curve.
• the length of the starting section 36 is selected in a way that the roller 15 rolls along it without influencing the free turning of the lifting rocker lever 6 around the rocker pivot 9, and therefore the pressure surface 7 of the lifting rocker lever 6 does not make a movement at the valve end 5 of the valve 2 in the direction of valve stem 4, without displacing the valve 2, and the extent of valve lift is zero.
• the roller 15 of the support lever 12 of the lifting rocker lever 6 rolls back and forth on the starting section 36 of the guiding curve 35.
• the continuous contact of the rollers 15 with the guiding curve 35 and with the outer surface 29 of the cam 28 is ensured by the tension of the spring 48.
• the guiding shaft 46 is turned - for example by means of the drive motor not shown - as a result of which the pinion 44 moves the rack 43, and along with it the guiding block 32 with its guiding curve 35 is also moved, in fact this is carried out in the direction of the camshaft 27 on the guiding pin 41.
• the roller 15 is in contact with the starting section 36 of the guiding curve 35, when the roller 25 of the single-arm rocker lever 19 is in contact with the cylindrical outer surface 31 of the cam 28.
• radius 40 of the second section 38 and the radius of the roller 15 influences the extent of high valve acceleration occurring at the time and following the valve opening. Because both cams 28 simultaneously lift the associated single-arm rocker lever 19, both lifting rocker levers 6 simultaneously actuate the valve 2 which is in contact, and furthermore the central lifting rocker lever 53 turns together with the lifting rocker levers 6, because all the three are steadily fixed on the rocker pivot 9, and hence valve 3 in the middle is moved.
• FIG. 5 A mechanism corresponding to the second embodiment example and suitable for actuating two valves 2 is shown in Figs. 5 and 6.
• the design enables the fitting of the mechanism into high revolution engines, which need limited lash adjustment for low noise and long life; this can be achieved by fitting a hydraulic lash adjustor for each valve.
• the guiding block 56 is guided along a curved guiding curve 57 for ensuring movement, the curve is of concave shape when viewed from the valve 2 and the rocker pivot 9, respectively, and it is arranged as a cylindrical surface section.
• the geometrical axis of the cylindrical surface is parallel with the camshaft 27 and on both sides 57 of the guiding block 56 the opposite surfaces 59 of each guiding groove 58 represent the guiding surfaces, between which the prongs 61 of a double-prong yoke 60 are fitted with their guiding surfaces 62 arranged as a counter-surface.
• the yoke head 63 of the two-prong yoke 60 is screwed to the cylinder head casting not shown, and the yoke head 63 and the stems 61 , respectively, are located around the protective pipe 47 of the spark plug not shown in the geometrical axis of the engine cylinder.
• the mechanism 1 has one single-arm rocker lever 19, the roller 25 of which is in permanent contact with the single roller 28.
• the roller 15 running on pin 17 and secured in the support lever 12 rests on the guiding surface 70 including the guiding curve 65 of the guiding block 56, and this said guiding surface - similarly to the first embodiment example - has starting section 66, first section 67, second section 68 and third section 69.
• each section is identical with that described in the first embodiment example, but the shapes of the starting section 66 and the first section 67 are different, because they are curved surfaces, the arc of which is matched to the curved shape of the surfaces 59 of the guiding groove 58 of the guiding block 56, and this said curve has an identical curving with the guiding surface 62 of the stem 61 of the yoke 60, and when running on this guiding surface, the guiding groove 57 enables the guiding block 56 to move.
• an actuating surface 72 including the line normal to the guiding surface 62 is around the eccentric 73 arranged on the control shaft 46 at the outer surface 74, the turning of which regulates the extent of lifting the valve 2.
• the roller 15 must be continuously supported by the guiding surface 70, and to this end on the single-arm rocker lever 19, in the vicinity of the bore 10 receiving the rocker pivot 9, on a side opposite the guiding block 32, a spring support surface 75 is arranged to support pressure spring 76.
• the pressure spring 76 is fitted between a suitable surface of the cylinder head not shown and the spring support surface 75 of the single-arm rocker lever 19.
• the guiding surface 62 of the stem 61 of the yoke 60 is a full curve-shaped cylindrical outer surface.
• An arc with the same centre is the starting section 66 of the guiding curve 65 of the guiding pin 32, and the first section 67 is arranged with an arc of a radius not so much different, and to this a zero valve lift is assigned, and to the latter only a lift not exceeding the lash is assigned.
• the radius of the second section 68 is changing continuously i.e. decreasing in an expedient way, until it approaches the radius of roller 15 and then the radius is continuously increasing until infinity, with a transition to the third section 69 which is expediently a flat surface with a straight generatrix.
• the shape of the fourth section 69 is not determined by operating requirements, but technologically a flat surface is recommended.
• the mechanism 1 according to the second embodiment example works as follows:
• the mechanism 1 changes the extent of lifting the valve 2 in a way that the control shaft 46 arranged as an engine control/regulating actuating member not shown turns together with the eccentric 73 fixed on it, and the outer surface 75 of the said eccentric displaces the movement surface 72 of the pin 71.
• the guiding block 32 slips on the guiding surface 62 of the prong 61 of the yoke 60, which said guiding surface is cylindrical. Consequently, the guiding block 32 moves along an arc, and it includes the guiding curve 65 and the guiding surface 70, which supports the roller 15.
• the operation of the mechanism shown in the second embodiment example is identical with that of the first embodiment example.
• the design of the single-arm rocker lever 19 and its lifting rocker levers 6 pinned on its rocker pivot 9 is identical with that in the second embodiment example, and they actuate two valves 2.
• the guiding shaft 46 fitted with the eccentric 73 is fitted, and the outer surface 74 of the eccentric 73 is in contact with the movement surfaces 72 located in the yoke head 79 of the guiding block 77.
• the said guiding block 77 is arranged in a way that it can be tilted around the axis of rotation and has the yoke prongs 79, at the ends 80 of which the pins 81 are fitted, and their geometrical axis is parallel with the generatrix of the movement surfaces 72 and with the guiding shaft 46, respectively.
• the pins 81 are pinned in the cylinder head casting not shown.
• the guiding surface 84 including the guiding curve 83 is located between the yoke prongs 79 of the guiding block 77, on the inner side 82 of the yoke head 78.
• the guiding curve 83 and the guiding surface 84, respectively, has the same sections as the guiding curve 65 and the guiding surface 70, respectively.
• the rollers 15 of the lifting rocker levers 6 have outer surfaces 16 resting on the guiding surfaces 84.
• the mechanism 1 varies the extent of lifting the valve 2 by turning the guiding shaft 46 arranged as an engine control/regulator member together with the eccentric 73 fixed on the said guiding shaft 46, and the outer surface of the said eccentric 73 displaces the movement surface 72 of the guiding block 77.
• the guiding block 77 turns around the pins 81 on the yoke prongs.
• the roll 15 is supported by the guiding curve 65 and the guiding surface 70 of the guiding block 77, and the said curve and surface move along an arc.
• the operation of the mechanism in the third embodiment example is identical with that in the second embodiment example.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve Device For Special Equipments (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=89980631

Family Applications (1)

Country Status (3)

Cited By (4)

Citations (3)

• 2002
  • 2002-07-18 HU HU0202368A patent/HUP0202368A2/hu unknown
• 2003
  • 2003-07-18 WO PCT/HU2003/000058 patent/WO2004009967A1/en not_active Application Discontinuation
  • 2003-07-18 AU AU2003249101A patent/AU2003249101A1/en not_active Abandoned

Patent Citations (3)

Non-Patent Citations (1)

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