WO2022224233A2 - Control of valves with locking system in internal combustion engines - Google Patents

Control of valves with locking system in internal combustion engines Download PDF

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Publication number
WO2022224233A2
WO2022224233A2 PCT/IB2022/057116 IB2022057116W WO2022224233A2 WO 2022224233 A2 WO2022224233 A2 WO 2022224233A2 IB 2022057116 W IB2022057116 W IB 2022057116W WO 2022224233 A2 WO2022224233 A2 WO 2022224233A2
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WO
WIPO (PCT)
Prior art keywords
pair
valve
locking
rotation axis
pulleys
Prior art date
Application number
PCT/IB2022/057116
Other languages
French (fr)
Other versions
WO2022224233A3 (en
WO2022224233A4 (en
Inventor
Nefton PALI
Original Assignee
Shala S.R.L.S.
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 Shala S.R.L.S. filed Critical Shala S.R.L.S.
Publication of WO2022224233A2 publication Critical patent/WO2022224233A2/en
Publication of WO2022224233A3 publication Critical patent/WO2022224233A3/en
Publication of WO2022224233A4 publication Critical patent/WO2022224233A4/en

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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
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/08—Valves guides; Sealing of valve stem, e.g. sealing by lubricant
    • 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
    • F01L1/30—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of positively opened and closed valves, i.e. desmodromic 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
    • F01L1/32—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for rotating lift valves, e.g. to diminish wear
    • 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
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L2003/25—Valve configurations in relation to engine
    • F01L2003/258—Valve configurations in relation to engine opening away from cylinder
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to a maneuver apparatus for intake and exhaust valves.
  • the present invention relates to a maneuver apparatus for intake and exhaust valves in combustion engines, capable of improving turbulence in the combustion chamber and ensuring high compression ratios.
  • valve control systems have a complete valve opening time limited by the positioning of the piston head in close proximity to the valve head at the start of the intake step and at the end of the exhaust step. This positioning can cause the engine to break in relation to the high rpm to which it is subjected.
  • valve control apparatuses Another drawback of known valve control apparatuses relates to the complete opening time of the valves which has a limit correlated with the geometry of the cams which does not allow strongly curved profiles due to the resistance force on the cam provided by the springs or by the compressed gas used to return the valves to the closed position. This resistance force becomes very consistent at high engine revs even with conventional cam shapes.
  • the object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of minimizing the aforementioned drawbacks.
  • the object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of guaranteeing high performance.
  • the object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of guaranteeing reduced turbulence in the combustion chamber as well as high compression ratios and high total opening and total closing times of the valves in relation to the engine cycle.
  • the maneuver apparatus for intake and exhaust valves comprises at least an intake and/or exhaust valve and maneuvering means of the valves, wherein each of the valves comprises a head and a stem, the stem being operatively coupled to the maneuvering means, and wherein the maneuvering means are able to move the valve along the axial direction of the symmetry axis of the stem between a first working position, in which the valve is arranged at the related valve seat, and a second working position, in which the valve is spaced apart from the valve seat, and vice versa
  • the maneuver apparatus is characterized in that the valve is arranged outside of the cylinder head and comprises at least a projection protruding from the stem and substantially perpendicular to the symmetry axis, wherein the maneuvering apparatus comprises a locking device provided with at least a locking element which is adapted to be operatively coupled to the projection, and wherein the maneuvering means are operatively coupled to the locking device and are adapted to move the locking device from a locking position, in which the locking element is at least partly engaged with
  • the opening of the valve with respect to its seat is prevented by the locking device when in the locking position, which has the task of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the explosion and compression phases. Likewise, opening of the valve is possible when the locking device is in the unlocked position.
  • the maneuvering means move the valve along the axial direction in a synchronized manner with the movement of the locking device between the first working position, when the locking element is in the locking position, and the second position working, when the locking element is in the unlocking position, and vice versa.
  • the maneuvering means comprise a first pair of counter-rotating camshafts, respectively provided with a first pair of cams and a second pair of cams, and a first actuating rod operatively connected to the first pair of camshafts, at a first portion, and to the stem, at a second portion opposite to the first portion, wherein the first actuating rod is provided with a first pair of pulleys and a second pair of pulleys arranged at the first portion, each of the first pair of pulleys and second pair of pulleys being aligned and concentric on opposite sides of the first actuating rod to a first pulley rotation axis and a second pulley rotation axis, respectively, and each of the first pair of pulleys and second pair of pulleys being operatively coupled to one of the first pair of camshafts, wherein the first actuating rod is constrained with respect to a first rod rotation axis interposed between the first pulley rotation axis and the second
  • the first pair of cams and the coupling with the first actuating rod therefore allow the valve to be completely moved to define the first working position and the second working position in a very short time and with a reduced inertia.
  • the maneuver apparatus comprises a centering element provided with an opening operatively coupled with at least a sliding portion of the stem and adapted to allow the movement of the valve along the axial direction of the symmetry axis of the stem between the first working position and the second working position, and wherein the opening and the sliding portion have a section perpendicular to the symmetry axis with a conformation different from the cylindrical one to prevent rotation of the sliding portion.
  • Such centering element allows preventing the rotation of the valve when in the first working position and subjected to the pressures from the combustion chamber.
  • the stem comprises a plurality of projections equidistant arranged radially with respect to said symmetry axis
  • the locking device comprises a locking disc arranged concentric with respect to the stem and provided with a plurality of unlocking openings equidistant arranged radially with respect to the symmetry axis and with a plurality of locking elements, each respectively interposed between two successive unlocking openings
  • the maneuvering means are adapted to rotate the locking disc with respect to the stem from the locking position, in which the locking elements are arranged at the projections to avoid the movement of the valve along the axial direction, to the unlocking position, in which the unlocking openings are arranged at the projections to allow the movement of the valve along the axial direction, and vice versa.
  • the locking disc can perform radial or semi-radial movements to allow the locking device to be arranged in the locking position or in the unlocking position.
  • the projections have a first sloping surface between two opposite ends, wherein the locking elements have a second sloping surface between two opposite ends, and wherein the first sloping surface and the second sloping surface are arranged facing each other and have a shape such as to fit together.
  • the sloping surfaces therefore allow coupling between the components which is gradually achieved during rotation to be improved, minimizing mutual interference.
  • the maneuvering means comprise a second pair of counter-rotating camshafts, respectively provided with a third pair of cams and a fourth pair of cams, and a second actuating rod operatively connected to the second pair of camshafts, at a first portion, and to the locking disc, at a second portion opposite to the first portion, wherein the second actuating rod is provided with a third pair of pulleys and a fourth pair of pulleys arranged at the first portion, each of the third pair of pulleys and fourth pair of pulleys being aligned and concentric on opposite sides of the second actuating rod to a third pulley rotation axis and a fourth pulley rotation axis, respectively, and each of the third pair of pulleys and fourth pair of pulleys being operatively coupled to one of the second pair of camshafts, wherein the second actuating rod is constrained with respect to a second rod rotation axis interposed between the third pulley rotation axis and the
  • the second pair of camshafts and the coupling with the second actuating rod therefore allow the locking disc to be completely moved to define the locking and unlocking positions very quickly and with reduced inertia.
  • the first pair of camshafts and the second pair of camshafts have the same modulus of rotation speed.
  • an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, according to the appended claims.
  • a vehicle comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, in accordance with the appended claims.
  • an electric generator comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, in accordance with the appended claims.
  • FIG. 1 is a sectional side plan view of the maneuver apparatus for intake and exhaust valves, according to the present invention, wherein the valve is in the first working position;
  • FIG. 2 is a sectional side plan view of the maneuver apparatus for the intake and exhaust valves of Figure 1, wherein the valve is in the second working position;
  • FIG. 3 is a top plan view of the maneuver means operatively coupled to the locking device of Figure 1, wherein the locking device is in the locking position;
  • FIG. 4 is a top plan view of the maneuver means operatively coupled to the locking device of Figure 1, wherein the locking device is in the unlocking position;
  • FIG. 5 is a front perspective view of the valve
  • FIG. 6 is a sectional side plan view of the projections and locking elements of Figure 1, wherein the locking elements are arranged in the unlocking position;
  • Figure 7 is a sectional side plan view of the projections and locking elements of Figure 1, wherein the locking elements are arranged in the locking position;
  • FIG. 8 is a schematic view of the first pair of camshafts in a first position
  • FIG. 9 is a schematic view of the first pair of camshafts in a second position.
  • Figures 1-9 illustrate a preferred embodiment of the maneuver apparatus 1 for intake and exhaust valves, described in greater detail hereinafter also with reference to an internal combustion engine.
  • the present invention also relates to a vehicle comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves according to the present invention, even if not illustrated.
  • the present invention also relates to an electric generator comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves according to the present invention, even if not illustrated.
  • the maneuver apparatus 1 for the intake and exhaust valves comprises an intake and/or exhaust valve 11, i.e. the valves respectively responsible for managing the introduction of the fuel mixture into the cylinder or pump casing to prevent the mixture from returning back or for managing the cylinder emptying adjustment, in order to prepare the engine for another thermal cycle.
  • the apparatus according to the present invention may be provided with several intake and/or exhaust valves, preferably in even numbers.
  • the valve 11, illustrated in detail in Figure 5, is of the poppet type normally used in internal combustion engines of the four-stroke type, works and is designed together with its own valve seat 50 to be able to regulate the introduction or emission of the gaseous mixtures, that is the air-fuel mixture or the exhaust gases, without these returning back or escaping from the cylinder during the compression and combustion steps.
  • Each valve 11 comprises a head 111 and a stem 200 and further comprises at least a projection protruding from the stem 200 and substantially perpendicular to the symmetry axis A.
  • the valve 11 comprises three projections 311, 411, 511 which protrude from the stem 200 where these proj ections 311, 411, 511 are arranged equidistant radially with respect to the symmetry axis A.
  • the valve seat 50 illustrated in greater detail in Figures 1 and 2, is made in such a way as to allow the head 111 to adhere perfectly and, therefore, to avoid leaks.
  • the valve 11 is, in fact, arranged externally to the cylinder head and the tolerances of micro-errors on the contact surface between the head 111 of the valve 11 and the seat 50 of the valve of the combustion chamber must be calculated in relation to the micro-expansion of the materials used for their construction when the temperature of the motor is nominal, and in relation to the coefficient of elasticity of the edge of the head 111 at that temperature.
  • Maneuvering means of the aforementioned valves 11 are part of the maneuver apparatus 1, where the stem 200 is operatively coupled to the aforesaid maneuvering means.
  • such maneuvering means are able to move the valve 11 between a first working position, in which the valve 11 is arranged at the related valve seat 50, and a second working position, in which the valve 11 is spaced apart from the valve seat 50, and vice-versa, along the axial direction of the symmetry axis A of the stem 200.
  • Figure 1 illustrates the valve 11 arranged in the first working position while Figure 2 illustrates the valve 11 arranged in the second working position.
  • the maneuver apparatus 1 further comprises a locking device 100 provided with at least a locking element 114, 115, 116 adapted to be operatively coupled to the proj ection 311, 411, 511.
  • the projections 311, 411, 511 have a first sloping surface 1311 between two opposite ends, as shown in Figure 5, and the locking elements 114, 115, 116 have a second sloping surface 1114 between two opposite ends.
  • the first sloping surface 1311 and the second sloping surface 1114 are arranged facing to each other and have a shape such as to fit together, as illustrated in greater detail in Figures 6 and 7.
  • the latter illustrate a sectional side plan view of the projection 311 and the locking element 114 wherein, respectively, the locking element 114 is arranged in the unlocking position with the first sloping surface 1311 and the second sloping surface 1114 spaced apart and the locking element 114 is arranged in the locking position with the first sloping surface 1311 and the second sloping surface 1114 arranged mating in contact.
  • the sloping surfaces 1311, 1114 therefore allow coupling between the components which is gradually achieved during rotation to be improved, minimizing mutual interference.
  • the maneuvering means are operatively coupled to the locking device 100 and are able to move the locking device 100 from a locking position, in which the locking element 114, 115, 116 is at least partly engaged with the projection 311, 411, 511 avoiding the movement of the valve 11 along the axial direction, to an unlocking position, in which the locking element 114, 115, 116 is disengaged from the projection 311, 411, 511 allowing the movement of the valve 11 along the axial direction, and vice-versa.
  • Figure 3 illustrates the locking device 100 arranged in the locking position while Figure 4 illustrates the same locking device 100 arranged in the unlocking position.
  • the opening of the valve 11 with respect to its seat 50 is prevented by the locking device 100 when in the locking position, which has the task of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the explosion and compression phases. Likewise, opening of the valve 11 is possible when the locking device 100 is in the unlocked position.
  • the locking device 100 comprises a locking disc 110 arranged concentric with respect to the stem 200 and provided with a plurality of unlocking openings 111, 112, 113 equidistant arranged radially with respect to the symmetry axis A and with a plurality of locking elements 114, 115, 116, each respectively interposed between two successive unlocking openings 111, 112, 113.
  • the maneuvering means are therefore able to rotate the locking disc 110 with respect to the stem 200 from the locking position, wherein the locking elements 114, 115, 116 are arranged at the projections 311, 411, 511 to avoid the movement of the valve 11 along the axial direction, to the unlocking position, wherein the unlocking openings 111, 112, 113 are arranged at the projections 311, 411, 511 to allow the movement of the valve 11 along the axial direction, and vice-versa.
  • the locking disc 110 can perform radial or semi-radial movements to allow the locking device 100 to be arranged in the locking position or in the unlocking position.
  • the use of the plurality of discs allows a better distribution of the forces during the movement of the locking discs themselves with respect to the valve, according to what is described in greater detail below.
  • the locking elements may be arranged alternately on each locking disc, depending on the number of locking discs used.
  • the locking device may be provided with a plurality of locking elements even without being provided with any locking disc, the movement of the locking elements being definable according to a plurality of different movements.
  • the maneuver apparatus 1 preferably comprises a centering element 500 provided with an opening operatively coupled with at least a sliding portion 211 ’ of the stem 200 and able to allow the movement of the valve 11 between the first working position and the second working position along the axial direction of the symmetry axis of the stem 200.
  • the opening and the sliding portion 211 ’ have a have a section perpendicular to the symmetry axis with a conformation different from the cylindrical one to prevent rotation of the sliding portion 211 ’ .
  • Such centering element 500 allows preventing the rotation of the valve 11 when in the first working position and subjected to the pressures from the combustion chamber.
  • the centering element 500 is defined by a support defined as an upper support fixed to the motor body.
  • the maneuver apparatus 1 is also provided with a lower support fixed to the motor body, provided in the central part with an opening aligned with the opening of the centering element 500 but, unlike the latter, of the circular type and which allows the sliding of the stem 200 to be guided in the portion at the head 111 of the valve 11, where the stem 200 has a circular section of such a size as to allow the aforementioned sliding.
  • the walls of the opening related to the centering element 500 in contact with the stem 200 at least partially support the torque generated by the forces acting on the projections 311, 411, 511 of the valve 11 when the locking device 100 is in the locking position with the locking elements 114, 115, 116 at least partially coupled to the projections 311, 411, 511.
  • the torque on the aforementioned projections 311, 411, 511 is generated by the pressures inside the combustion chamber.
  • the forces acting on the locking elements 114, 115, 116 and on the projections 311, 411, 511 can be very high, the decomposition of these forces on the contact surface thereof produces a reduced torque on the symmetry axis A of the stem 200 and, consequently, on the locking device 100.
  • the maneuvering means move the valve 11 along the axial direction in a synchronized manner with the movement of the locking element 100 between the first working position, when the locking element 114, 115, 116 is in the locking position, and the second position working, when the locking element 114, 115, 116 is in the unlocking position, and vice versa.
  • the maneuvering means comprise a first pair 201, 202 of counter-rotating camshafts and a second pair 401, 402 of counter-rotating camshafts, respectively used to actuate the stem 200 and the locking disc 110.
  • the maneuvering means comprise a first pair of counter-rotating camshafts 201, 202, respectively provided with a first pair of cams 211, 221 and with a second pair of cams 212, 222, and a first actuating rod (210) operatively connected to said the pair of camshafts 201, 202, at a first portion, and to the stem 200, at a second portion opposite to the first portion.
  • the maneuvering means preferably comprise a second pair of counter-rotating camshafts 401, 402, respectively provided with a third pair of cams and with a fourth pair of cams, and a second actuating rod 410 operatively connected to the second pair of camshafts 401, 402, at a first portion, and to the locking disc 110, at a second portion opposite to the first portion.
  • the aforesaid maneuvering means may also be defined by means of elements different from the camshafts, for example by means of electric motors, electric motors or hydraulic systems, adapted to define the positioning of both the valve and the locking element.
  • the aforementioned first pair 201, 202 of camshafts and second pair 401, 402 of camshafts therefore define a synchronized movement of the valve 11 along the axial direction and of the locking element 100 between the first working position and the second working position. Furthermore, preferably the first pair 201, 202 of camshafts and the second pair 401, 402 of camshafts have the same modulus of rotation speed.
  • the first pair 201, 202 of camshafts and the coupling with the first actuating rod 210 therefore allow the valve 11 to be completely moved by means of the related stem 200 to define the first working position and the second working position in a very short time and with a reduced inertia.
  • the first actuating rod 210 is provided with a first pair 231, 241 of pulleys and with a second pair 232, 242 of pulleys arranged at the first portion, as illustrated in the related Figures 8 and 9.
  • Each first pair 231, 241 of pulleys and second pair 232, 242 of pulleys is aligned and concentric on opposite sides of the first actuating rod 210 respectively to a first pulley rotation axis and a second pulley rotation axis (not shown).
  • Each first pair 231, 241 of pulleys and second pair 232, 242 of pulleys is also operatively coupled with one of the first pair 201, 202 of camshafts.
  • Figure 8 illustrates a schematic view of the first pair of camshafts in a first position
  • Figure 9 illustrates a schematic view of the first pair of camshafts in a second position.
  • the first actuating rod 210 is constrained around a first rod rotation axis interposed between the first pulley rotation axis and the second pulley rotation axis.
  • the distance D1 between the first pulley rotation axis and the second pulley rotation axis is lower than the sum of the major radii D2, D3 of the first pairs of cams 211, 221 and second pair of cams 212, 222.
  • the first pair 201, 202 of camshafts has an opposite direction of rotation, wherein a camshaft 201 rotates counter-clockwise while the remaining camshaft 202 rotates clockwise.
  • the cam 211 of the first pair of cams has the function of not allowing free movements of the first actuating rod 210 during the opening process of the valve 11.
  • the remaining cam 221 of the same first pair of cams provides the movement for closing the aforementioned valve 11.
  • the cam 212 of the second pair of cams has the function of not allowing any free movement of the first actuating rod 210 during the closing process of the aforementioned valve 11.
  • the remaining cam 222 of the same first pair of cams provides the movement for opening the aforementioned valve 11.
  • the distance of the end of the first actuating rod 210 from its rotation axis must be a sufficiently large multiple of the distance of the same axis from the second pulley rotation axis.
  • the aforementioned multiple is sufficiently large to obtain a sufficiently large movement of the valve 11 with a small lift of the cam the cam 222 of the second pair of cams. This contributes to the short opening and closing cycles of the valves.
  • the choice of the aforementioned sufficiently large multiple also allows minor micro variations of the contact surface of the first pair 231, 241 of pulleys and of the second pair 232, 242 of pulleys with the corresponding first pair 211, 221 of cams and second pair 212, 222 of cams, due to the micro-deformations of the contour of the head 111 of the valve 11 caused by the temperature variations in different situations of the combustion engine. Furthermore, the distance of the first pulley rotation axis from the same rotation axis of the first actuating rod 210 is equal to the distance of the same rotation axis from the second pulley rotation axis.
  • distance D1 between the first pulley rotation axis and the second pulley rotation axis is lower than the sum of the major radii D2, D3 of the first pairs of cams 211, 221 and second pair of cams 212, 222 in such a way as to contribute to the short opening and closing times of the valve 11.
  • This is possible by means of an offset positioning of the first pair of cams 211, 221 and of the second pair of cams 212, 222 along the axis of the corresponding camshafts 201, 202.
  • the first actuating rod 210 as well as the corresponding first pair 231, 241 of pulleys and second pair 232, 242 of pulleys, the respective first pair 211, 221 of cams and second pair 212, 222 of cams in contact with these and the first pair 201, 202 of camshafts must withstand at least the pressure developed in the combustion chamber during the explosion end process, for the exhaust valves, and the beginning of the compression process, for the intake valves, when the locking device 100 of the corresponding valves is respectively in the opening/closing step.
  • the weight of the aforesaid components can be low with respect to the forces acting on each of them.
  • the fact that the weight of the first actuating rod 210 and of the first pair 231, 241 of pulleys and second pair 232, 242 of pulleys can be low also contributes to the possibility of using very curved profiles by the cam 222 of the second pair of cams responsible for the short intermediate opening cycle of the valve 11 as well as by the cam 221 of the first pair of cams responsible for the short intermediate closing cycle of the valve 11.
  • the second pair 401, 402 of camshafts and the coupling with the second actuating rod 410 therefore allow the locking disc 110 to be completely moved to define the locking and unlocking positions very quickly and with reduced inertia.
  • the second actuating rod 410 is provided with a third pair of pulleys and of a fourth pair of pulleys arranged at the first portion, each of the third pair of pulleys and fourth pair of pulleys being aligned and concentric respectively to a third pulley rotation axis and to a fourth pulley rotation axis on opposite sides of said second actuating rod, and each of the third pair of pulleys and of fourth pair of pulleys is operatively coupled with one of the second pair of camshafts 401, 402.
  • the second actuating rod 410 is constrained around a second rod rotation axis interposed between the third pulley rotation axis and the fourth pulley rotation axis.
  • the distance D4 between the third pulley rotation axis and the fourth pulley rotation axis is lower than the sum of the major radii of the third pairs of cams and fourth pair of cams.
  • the locking device 100 i.e. the locking disc 110
  • the locking device 100 has the function of allowing the axial movement of the corresponding valve 11 during the intake process for the intake valves or the exhaust process for the exhaust valves, of lock by means of the relative locking elements 114, 115, 116 the axial movement of the valve 11 during the compression and explosion process, of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the compression and explosion process.
  • the second actuating rod 410 defines a semi-radial movement to allow the actuation of the locking disk 110.
  • the locking device 100 i.e. the locking disc 110
  • the locking device 100 in contact with the second actuating rod 410 transmits its semi-radial movement to the other devices 100, or to the locking discs 110, by means of suitable gears (not shown) arranged on the respective contact surfaces.
  • the locking device 100, or the related locking disc 110 is completely open just before the intake or exhaust valve 11 begins to move in the opposite direction to the piston head.
  • the same locking device 100, or the related locking disc 110 begins its closing configuration immediately after the intake or exhaust valve 11 stops its movement towards the piston head.
  • One of the cams of the fourth pair of cams controls the movement of the second actuating rod 410 by opening the locking device 100, or the locking disc 110, while one of the cams of the third pair of cams, the one furthest away from the free end of the second actuating rod 410, has the function of not allowing free movements of the same second actuating rod 410 during the opening process of the locking device 100, or of the locking disc 110.
  • the other cam of the third pair of cams provides for the semi-radial movement for closing the locking device 100, or rather of the locking disc 110, while the other cam of the fourth pair of cams has the function of not allowing free movements of the second actuating rod 410 during the closing process of the locking device 100, or rather of the locking disc 110.
  • the ratio between the distance of the end of the second actuating rod 410 in contact with the locking device 100, or with the locking disc 110, and the rotation axis of the same second actuating rod 410 and the distance of this rotation axis from the common axis of the fourth pair of pulleys must be as large as possible so as to minimize the intermediate opening and closing cycles of the locking device 100 using a small lift of the cams.
  • the intermediate short closing cycle of the locking device 100 is also possible considering that the resistance torque on the valve axis locking device 100 which is present only at the end of the valve block closing is very low in consideration of the choice of the aforementioned geometries of the second actuating rod 410, of the geometries of the head 110 of the valve 11 and of the geometries of the respective locking elements 114, 115, 116 and project 311, 411, 511.
  • the second actuating rod 410 as well as the corresponding third pair of pulleys and fourth pair of pulleys, the respective third pair of cams and fourth pair of cams in contact with them and the second pair of camshafts support at least the torque on the locking device 100, i.e. on the locking disc 110, generated by the pressure developed in the combustion chamber during the explosion and compression process. Considering that the aforementioned torque is reduced, the weight considerations already expressed above can be applied.
  • the present invention therefore allows the drawbacks of valve control systems for combustion engines of the known type to be obviated.
  • the present invention allows providing a maneuver apparatus for the intake and exhaust valve which allow a greater efficiency of fuel management at normal speeds, as well as the achievement of very high powers, torques and speeds of the combustion engine without a very consistent increase in fuel consumption.
  • the apparatus according to the invention also allows defining much shorter intermediate opening and closing times of the valves, longer and much more efficient intake and exhaust processes compared to known valve control systems.
  • the high efficiency of the suction and discharge process of the apparatus according to the invention is also guaranteed by a non-obstructive position of the valves during these processes.

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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)

Abstract

The present invention relates to a maneuver apparatus (1) for intake and exhaust valves wherein the maneuvering means are adapted to move the valve (11) along the axial direction of the symmetry axis (A) of the stem (200 ) between a first working position, in which the valve (11) is arranged at the related valve seat (50), and a second working position, in which the valve (11) is spaced apart from the valve seat (50), and vice versa, wherein the valve (11) is arranged outside of the cylinder head and comprises at least a projection (311, 411, 511) protruding from the stem (200) and substantially perpendicular to the symmetry axis (A), wherein a locking device (100) provided with at least a locking element (114, 115, 116) is adapted to be operatively coupled with the projection (311, 411, 511), and wherein the maneuvering means are operatively coupled to the locking device (100) and are adapted to move the locking device (100) from a locking position, in which the locking element (114, 115, 116) is at least partially coupled to the projection (311, 411, 511) to prevent movement of the valve (11) along the axial direction, to an unlocking position, in which the locking element (114, 115, 116) is disengaged from the projection (311, 411, 511) to allow movement of the valve (11) along the axial direction, and vice versa.

Description

“Control of valves with locking system in internal combustion engines”
Description
Field of the invention
The present invention relates to a maneuver apparatus for intake and exhaust valves.
In particular, the present invention relates to a maneuver apparatus for intake and exhaust valves in combustion engines, capable of improving turbulence in the combustion chamber and ensuring high compression ratios.
Prior art
In the field of internal combustion engines, the use of apparatuses for controlling intake and exhaust valves is known. In particular, these apparatuses operate in obstructive positions of the intake and exhaust sleeve of the internal combustion engine. This limits the amount of air, i.e. air-fuel mixture, during the intake step and the expulsion speed of the exhaust gases. In addition, a fuel deposit on the intake valve head is determined in internal combustion engines without direct injection.
In addition, known valve control systems have a complete valve opening time limited by the positioning of the piston head in close proximity to the valve head at the start of the intake step and at the end of the exhaust step. This positioning can cause the engine to break in relation to the high rpm to which it is subjected.
Another drawback of known valve control apparatuses relates to the complete opening time of the valves which has a limit correlated with the geometry of the cams which does not allow strongly curved profiles due to the resistance force on the cam provided by the springs or by the compressed gas used to return the valves to the closed position. This resistance force becomes very consistent at high engine revs even with conventional cam shapes.
It would therefore be desirable to have a maneuver apparatus for intake and exhaust valves capable of minimizing the drawbacks described above. In this regard, it would be desirable to have a maneuver apparatus for intake and exhaust valves capable of significantly improving the performance of an internal combustion engine.
Summary of the invention
The object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of minimizing the aforementioned drawbacks.
In this regard, the object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of guaranteeing high performance. In particular, the object of the present invention is to provide a maneuver apparatus for intake and exhaust valves capable of guaranteeing reduced turbulence in the combustion chamber as well as high compression ratios and high total opening and total closing times of the valves in relation to the engine cycle.
The aforementioned objects are achieved by a maneuver apparatus for intake and exhaust valves, in accordance with the appended claims.
The maneuver apparatus for intake and exhaust valves comprises at least an intake and/or exhaust valve and maneuvering means of the valves, wherein each of the valves comprises a head and a stem, the stem being operatively coupled to the maneuvering means, and wherein the maneuvering means are able to move the valve along the axial direction of the symmetry axis of the stem between a first working position, in which the valve is arranged at the related valve seat, and a second working position, in which the valve is spaced apart from the valve seat, and vice versa, the maneuver apparatus is characterized in that the valve is arranged outside of the cylinder head and comprises at least a projection protruding from the stem and substantially perpendicular to the symmetry axis, wherein the maneuvering apparatus comprises a locking device provided with at least a locking element which is adapted to be operatively coupled to the projection, and wherein the maneuvering means are operatively coupled to the locking device and are adapted to move the locking device from a locking position, in which the locking element is at least partly engaged with the projection avoiding the movement of the valve along the axial direction, to an unlocking position, in which the locking element is disengaged from the projection allowing the movement of the valve along the axial direction, and vice versa.
Therefore, the opening of the valve with respect to its seat is prevented by the locking device when in the locking position, which has the task of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the explosion and compression phases. Likewise, opening of the valve is possible when the locking device is in the unlocked position.
According to an embodiment, the maneuvering means move the valve along the axial direction in a synchronized manner with the movement of the locking device between the first working position, when the locking element is in the locking position, and the second position working, when the locking element is in the unlocking position, and vice versa.
In particular, the maneuvering means comprise a first pair of counter-rotating camshafts, respectively provided with a first pair of cams and a second pair of cams, and a first actuating rod operatively connected to the first pair of camshafts, at a first portion, and to the stem, at a second portion opposite to the first portion, wherein the first actuating rod is provided with a first pair of pulleys and a second pair of pulleys arranged at the first portion, each of the first pair of pulleys and second pair of pulleys being aligned and concentric on opposite sides of the first actuating rod to a first pulley rotation axis and a second pulley rotation axis, respectively, and each of the first pair of pulleys and second pair of pulleys being operatively coupled to one of the first pair of camshafts, wherein the first actuating rod is constrained with respect to a first rod rotation axis interposed between the first pulley rotation axis and the second pulley rotation axis, and wherein the distance between the first pulley rotation axis and the second pulley rotation axis is lower than the sum of the major radii of the first pair of cams and second pair of cams.
The first pair of cams and the coupling with the first actuating rod therefore allow the valve to be completely moved to define the first working position and the second working position in a very short time and with a reduced inertia.
According to an embodiment, wherein the maneuver apparatus comprises a centering element provided with an opening operatively coupled with at least a sliding portion of the stem and adapted to allow the movement of the valve along the axial direction of the symmetry axis of the stem between the first working position and the second working position, and wherein the opening and the sliding portion have a section perpendicular to the symmetry axis with a conformation different from the cylindrical one to prevent rotation of the sliding portion.
Such centering element allows preventing the rotation of the valve when in the first working position and subjected to the pressures from the combustion chamber.
According to an embodiment, the stem comprises a plurality of projections equidistant arranged radially with respect to said symmetry axis, wherein the locking device comprises a locking disc arranged concentric with respect to the stem and provided with a plurality of unlocking openings equidistant arranged radially with respect to the symmetry axis and with a plurality of locking elements, each respectively interposed between two successive unlocking openings, and wherein the maneuvering means are adapted to rotate the locking disc with respect to the stem from the locking position, in which the locking elements are arranged at the projections to avoid the movement of the valve along the axial direction, to the unlocking position, in which the unlocking openings are arranged at the projections to allow the movement of the valve along the axial direction, and vice versa.
In this way, the locking disc can perform radial or semi-radial movements to allow the locking device to be arranged in the locking position or in the unlocking position.
According to an embodiment, the projections have a first sloping surface between two opposite ends, wherein the locking elements have a second sloping surface between two opposite ends, and wherein the first sloping surface and the second sloping surface are arranged facing each other and have a shape such as to fit together.
The sloping surfaces therefore allow coupling between the components which is gradually achieved during rotation to be improved, minimizing mutual interference.
In particular, the maneuvering means comprise a second pair of counter-rotating camshafts, respectively provided with a third pair of cams and a fourth pair of cams, and a second actuating rod operatively connected to the second pair of camshafts, at a first portion, and to the locking disc, at a second portion opposite to the first portion, wherein the second actuating rod is provided with a third pair of pulleys and a fourth pair of pulleys arranged at the first portion, each of the third pair of pulleys and fourth pair of pulleys being aligned and concentric on opposite sides of the second actuating rod to a third pulley rotation axis and a fourth pulley rotation axis, respectively, and each of the third pair of pulleys and fourth pair of pulleys being operatively coupled to one of the second pair of camshafts, wherein the second actuating rod is constrained with respect to a second rod rotation axis interposed between the third pulley rotation axis and the fourth pulley rotation axis, and wherein the distance between the third pulley rotation axis and the fourth pulley rotation axis is lower than the sum of the major radii of the third pair of cams and fourth pair of cams.
The second pair of camshafts and the coupling with the second actuating rod therefore allow the locking disc to be completely moved to define the locking and unlocking positions very quickly and with reduced inertia.
According to an embodiment, the first pair of camshafts and the second pair of camshafts have the same modulus of rotation speed.
The aforementioned objects are achieved by an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, according to the appended claims. Moreover, the aforementioned objects are achieved by a vehicle comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, in accordance with the appended claims.
Finally, the aforementioned objects are achieved by an electric generator comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves, in accordance with the appended claims.
Description of the figures
These and further features and advantages of the present invention will become apparent from the description of the preferred embodiment, illustrated by way of non-limiting example in the accompanying figures, in which: - Figure 1 is a sectional side plan view of the maneuver apparatus for intake and exhaust valves, according to the present invention, wherein the valve is in the first working position;
- Figure 2 is a sectional side plan view of the maneuver apparatus for the intake and exhaust valves of Figure 1, wherein the valve is in the second working position;
- Figure 3 is a top plan view of the maneuver means operatively coupled to the locking device of Figure 1, wherein the locking device is in the locking position;
- Figure 4 is a top plan view of the maneuver means operatively coupled to the locking device of Figure 1, wherein the locking device is in the unlocking position;
- Figure 5 is a front perspective view of the valve;
- Figure 6 is a sectional side plan view of the projections and locking elements of Figure 1, wherein the locking elements are arranged in the unlocking position;
- Figure 7 is a sectional side plan view of the projections and locking elements of Figure 1, wherein the locking elements are arranged in the locking position;
- Figure 8 is a schematic view of the first pair of camshafts in a first position;
- Figure 9 is a schematic view of the first pair of camshafts in a second position.
Detailed description of the invention
Figures 1-9 illustrate a preferred embodiment of the maneuver apparatus 1 for intake and exhaust valves, described in greater detail hereinafter also with reference to an internal combustion engine.
The present invention also relates to a vehicle comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves according to the present invention, even if not illustrated.
Likewise, the present invention also relates to an electric generator comprising an internal combustion engine comprising a maneuver apparatus for intake and exhaust valves according to the present invention, even if not illustrated.
The maneuver apparatus 1 for the intake and exhaust valves comprises an intake and/or exhaust valve 11, i.e. the valves respectively responsible for managing the introduction of the fuel mixture into the cylinder or pump casing to prevent the mixture from returning back or for managing the cylinder emptying adjustment, in order to prepare the engine for another thermal cycle.
According to further embodiments, not illustrated, the apparatus according to the present invention may be provided with several intake and/or exhaust valves, preferably in even numbers.
The valve 11, illustrated in detail in Figure 5, is of the poppet type normally used in internal combustion engines of the four-stroke type, works and is designed together with its own valve seat 50 to be able to regulate the introduction or emission of the gaseous mixtures, that is the air-fuel mixture or the exhaust gases, without these returning back or escaping from the cylinder during the compression and combustion steps.
Each valve 11 comprises a head 111 and a stem 200 and further comprises at least a projection protruding from the stem 200 and substantially perpendicular to the symmetry axis A. In particular, in the embodiment illustrated herein, the valve 11 comprises three projections 311, 411, 511 which protrude from the stem 200 where these proj ections 311, 411, 511 are arranged equidistant radially with respect to the symmetry axis A. According to further embodiments, it is also possible to provide a different number for the projections, i.e. a different arrangement and not substantially equidistant radially with respect to the aforementioned symmetry axis A. The valve seat 50, illustrated in greater detail in Figures 1 and 2, is made in such a way as to allow the head 111 to adhere perfectly and, therefore, to avoid leaks. The valve 11 is, in fact, arranged externally to the cylinder head and the tolerances of micro-errors on the contact surface between the head 111 of the valve 11 and the seat 50 of the valve of the combustion chamber must be calculated in relation to the micro-expansion of the materials used for their construction when the temperature of the motor is nominal, and in relation to the coefficient of elasticity of the edge of the head 111 at that temperature.
Maneuvering means of the aforementioned valves 11 are part of the maneuver apparatus 1, where the stem 200 is operatively coupled to the aforesaid maneuvering means. In particular, such maneuvering means are able to move the valve 11 between a first working position, in which the valve 11 is arranged at the related valve seat 50, and a second working position, in which the valve 11 is spaced apart from the valve seat 50, and vice-versa, along the axial direction of the symmetry axis A of the stem 200. Figure 1 illustrates the valve 11 arranged in the first working position while Figure 2 illustrates the valve 11 arranged in the second working position.
The maneuver apparatus 1 according to the present invention further comprises a locking device 100 provided with at least a locking element 114, 115, 116 adapted to be operatively coupled to the proj ection 311, 411, 511.
In the preferred embodiment, the projections 311, 411, 511 have a first sloping surface 1311 between two opposite ends, as shown in Figure 5, and the locking elements 114, 115, 116 have a second sloping surface 1114 between two opposite ends. The first sloping surface 1311 and the second sloping surface 1114 are arranged facing to each other and have a shape such as to fit together, as illustrated in greater detail in Figures 6 and 7. The latter illustrate a sectional side plan view of the projection 311 and the locking element 114 wherein, respectively, the locking element 114 is arranged in the unlocking position with the first sloping surface 1311 and the second sloping surface 1114 spaced apart and the locking element 114 is arranged in the locking position with the first sloping surface 1311 and the second sloping surface 1114 arranged mating in contact.
The sloping surfaces 1311, 1114 therefore allow coupling between the components which is gradually achieved during rotation to be improved, minimizing mutual interference.
To this end, the maneuvering means are operatively coupled to the locking device 100 and are able to move the locking device 100 from a locking position, in which the locking element 114, 115, 116 is at least partly engaged with the projection 311, 411, 511 avoiding the movement of the valve 11 along the axial direction, to an unlocking position, in which the locking element 114, 115, 116 is disengaged from the projection 311, 411, 511 allowing the movement of the valve 11 along the axial direction, and vice-versa. Figure 3 illustrates the locking device 100 arranged in the locking position while Figure 4 illustrates the same locking device 100 arranged in the unlocking position. Therefore, the opening of the valve 11 with respect to its seat 50 is prevented by the locking device 100 when in the locking position, which has the task of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the explosion and compression phases. Likewise, opening of the valve 11 is possible when the locking device 100 is in the unlocked position.
In particular, according to the preferred embodiment illustrated herein, the locking device 100 comprises a locking disc 110 arranged concentric with respect to the stem 200 and provided with a plurality of unlocking openings 111, 112, 113 equidistant arranged radially with respect to the symmetry axis A and with a plurality of locking elements 114, 115, 116, each respectively interposed between two successive unlocking openings 111, 112, 113.
The maneuvering means are therefore able to rotate the locking disc 110 with respect to the stem 200 from the locking position, wherein the locking elements 114, 115, 116 are arranged at the projections 311, 411, 511 to avoid the movement of the valve 11 along the axial direction, to the unlocking position, wherein the unlocking openings 111, 112, 113 are arranged at the projections 311, 411, 511 to allow the movement of the valve 11 along the axial direction, and vice-versa.
In this way, the locking disc 110 can perform radial or semi-radial movements to allow the locking device 100 to be arranged in the locking position or in the unlocking position. According to further embodiments, not illustrated, it is also possible to provide for the use of two or more locking discs arranged concentric and in succession with respect to the stem. In this case, the use of the plurality of discs allows a better distribution of the forces during the movement of the locking discs themselves with respect to the valve, according to what is described in greater detail below. In this case, the locking elements may be arranged alternately on each locking disc, depending on the number of locking discs used. Furthermore, according to further embodiments, not shown, the locking device may be provided with a plurality of locking elements even without being provided with any locking disc, the movement of the locking elements being definable according to a plurality of different movements. The maneuver apparatus 1 preferably comprises a centering element 500 provided with an opening operatively coupled with at least a sliding portion 211 ’ of the stem 200 and able to allow the movement of the valve 11 between the first working position and the second working position along the axial direction of the symmetry axis of the stem 200. The opening and the sliding portion 211 ’ have a have a section perpendicular to the symmetry axis with a conformation different from the cylindrical one to prevent rotation of the sliding portion 211 ’ . Such centering element 500 allows preventing the rotation of the valve 11 when in the first working position and subjected to the pressures from the combustion chamber.
In the preferred embodiment described herein, the centering element 500 is defined by a support defined as an upper support fixed to the motor body. The maneuver apparatus 1 is also provided with a lower support fixed to the motor body, provided in the central part with an opening aligned with the opening of the centering element 500 but, unlike the latter, of the circular type and which allows the sliding of the stem 200 to be guided in the portion at the head 111 of the valve 11, where the stem 200 has a circular section of such a size as to allow the aforementioned sliding.
The walls of the opening related to the centering element 500 in contact with the stem 200 at least partially support the torque generated by the forces acting on the projections 311, 411, 511 of the valve 11 when the locking device 100 is in the locking position with the locking elements 114, 115, 116 at least partially coupled to the projections 311, 411, 511. The torque on the aforementioned projections 311, 411, 511 is generated by the pressures inside the combustion chamber. Although the forces acting on the locking elements 114, 115, 116 and on the projections 311, 411, 511 can be very high, the decomposition of these forces on the contact surface thereof produces a reduced torque on the symmetry axis A of the stem 200 and, consequently, on the locking device 100.
Preferably, the maneuvering means move the valve 11 along the axial direction in a synchronized manner with the movement of the locking element 100 between the first working position, when the locking element 114, 115, 116 is in the locking position, and the second position working, when the locking element 114, 115, 116 is in the unlocking position, and vice versa.
In particular, the maneuvering means comprise a first pair 201, 202 of counter-rotating camshafts and a second pair 401, 402 of counter-rotating camshafts, respectively used to actuate the stem 200 and the locking disc 110. Preferably, the maneuvering means comprise a first pair of counter-rotating camshafts 201, 202, respectively provided with a first pair of cams 211, 221 and with a second pair of cams 212, 222, and a first actuating rod (210) operatively connected to said the pair of camshafts 201, 202, at a first portion, and to the stem 200, at a second portion opposite to the first portion. Likewise, the maneuvering means preferably comprise a second pair of counter-rotating camshafts 401, 402, respectively provided with a third pair of cams and with a fourth pair of cams, and a second actuating rod 410 operatively connected to the second pair of camshafts 401, 402, at a first portion, and to the locking disc 110, at a second portion opposite to the first portion.
The aforesaid maneuvering means may also be defined by means of elements different from the camshafts, for example by means of electric motors, electric motors or hydraulic systems, adapted to define the positioning of both the valve and the locking element.
The aforementioned first pair 201, 202 of camshafts and second pair 401, 402 of camshafts therefore define a synchronized movement of the valve 11 along the axial direction and of the locking element 100 between the first working position and the second working position. Furthermore, preferably the first pair 201, 202 of camshafts and the second pair 401, 402 of camshafts have the same modulus of rotation speed.
The first pair 201, 202 of camshafts and the coupling with the first actuating rod 210 therefore allow the valve 11 to be completely moved by means of the related stem 200 to define the first working position and the second working position in a very short time and with a reduced inertia.
In particular, the first actuating rod 210 is provided with a first pair 231, 241 of pulleys and with a second pair 232, 242 of pulleys arranged at the first portion, as illustrated in the related Figures 8 and 9. Each first pair 231, 241 of pulleys and second pair 232, 242 of pulleys is aligned and concentric on opposite sides of the first actuating rod 210 respectively to a first pulley rotation axis and a second pulley rotation axis (not shown). Each first pair 231, 241 of pulleys and second pair 232, 242 of pulleys is also operatively coupled with one of the first pair 201, 202 of camshafts.
In this regard, Figure 8 illustrates a schematic view of the first pair of camshafts in a first position, while Figure 9 illustrates a schematic view of the first pair of camshafts in a second position.
Taking into consideration the aforementioned Figures 8 and 9 in combination with Figures 1 and 2, it can be identified that the first actuating rod 210 is constrained around a first rod rotation axis interposed between the first pulley rotation axis and the second pulley rotation axis. The distance D1 between the first pulley rotation axis and the second pulley rotation axis is lower than the sum of the major radii D2, D3 of the first pairs of cams 211, 221 and second pair of cams 212, 222.
The first pair 201, 202 of camshafts has an opposite direction of rotation, wherein a camshaft 201 rotates counter-clockwise while the remaining camshaft 202 rotates clockwise. Considering the camshaft 201, the cam 211 of the first pair of cams has the function of not allowing free movements of the first actuating rod 210 during the opening process of the valve 11. Likewise, the remaining cam 221 of the same first pair of cams provides the movement for closing the aforementioned valve 11.
Considering the camshaft 202, the cam 212 of the second pair of cams has the function of not allowing any free movement of the first actuating rod 210 during the closing process of the aforementioned valve 11. Likewise, the remaining cam 222 of the same first pair of cams provides the movement for opening the aforementioned valve 11.
With reference to Figures 1 and 2, the distance of the end of the first actuating rod 210 from its rotation axis must be a sufficiently large multiple of the distance of the same axis from the second pulley rotation axis. The aforementioned multiple is sufficiently large to obtain a sufficiently large movement of the valve 11 with a small lift of the cam the cam 222 of the second pair of cams. This contributes to the short opening and closing cycles of the valves. The choice of the aforementioned sufficiently large multiple also allows minor micro variations of the contact surface of the first pair 231, 241 of pulleys and of the second pair 232, 242 of pulleys with the corresponding first pair 211, 221 of cams and second pair 212, 222 of cams, due to the micro-deformations of the contour of the head 111 of the valve 11 caused by the temperature variations in different situations of the combustion engine. Furthermore, the distance of the first pulley rotation axis from the same rotation axis of the first actuating rod 210 is equal to the distance of the same rotation axis from the second pulley rotation axis. Therefore, as described above, distance D1 between the first pulley rotation axis and the second pulley rotation axis is lower than the sum of the major radii D2, D3 of the first pairs of cams 211, 221 and second pair of cams 212, 222 in such a way as to contribute to the short opening and closing times of the valve 11. This is possible by means of an offset positioning of the first pair of cams 211, 221 and of the second pair of cams 212, 222 along the axis of the corresponding camshafts 201, 202.
It is possible to use very curved profiles on the part of the cam 222 of the second pair of cams, responsible for the short intermediate opening cycle of the valve 11, by making the choice of a small radius of the pulley 242 of the second pair of pulleys and the choice of a small radius connecting the intermediate part of the opening profile of the same cam 222, considering that the force necessary for the opening movement of the valve 11 is very low due to the very low mass of the valve 11 itself. It is also possible to use very curved profiles on the part of the cam 221 of the first pair of cams, responsible for the short intermediate closing cycle of the valve
11, by making the choice of a small radius of the pulley 241 of the first pair of pulleys and the choice of a small radius connecting the intermediate part of the closing profile of the same cam 222, considering that the force necessary for the closing movement of the valve 11 is very low due to the very small mass of the valve 11 itself. In the construction of the apparatus 1 according to the present invention, the first actuating rod 210 as well as the corresponding first pair 231, 241 of pulleys and second pair 232, 242 of pulleys, the respective first pair 211, 221 of cams and second pair 212, 222 of cams in contact with these and the first pair 201, 202 of camshafts must withstand at least the pressure developed in the combustion chamber during the explosion end process, for the exhaust valves, and the beginning of the compression process, for the intake valves, when the locking device 100 of the corresponding valves is respectively in the opening/closing step. Considering that the aforesaid pressures are low, the weight of the aforesaid components can be low with respect to the forces acting on each of them. In particular, the fact that the weight of the first actuating rod 210 and of the first pair 231, 241 of pulleys and second pair 232, 242 of pulleys can be low also contributes to the possibility of using very curved profiles by the cam 222 of the second pair of cams responsible for the short intermediate opening cycle of the valve 11 as well as by the cam 221 of the first pair of cams responsible for the short intermediate closing cycle of the valve 11.
Likewise, the second pair 401, 402 of camshafts and the coupling with the second actuating rod 410 therefore allow the locking disc 110 to be completely moved to define the locking and unlocking positions very quickly and with reduced inertia.
In particular, the second actuating rod 410 is provided with a third pair of pulleys and of a fourth pair of pulleys arranged at the first portion, each of the third pair of pulleys and fourth pair of pulleys being aligned and concentric respectively to a third pulley rotation axis and to a fourth pulley rotation axis on opposite sides of said second actuating rod, and each of the third pair of pulleys and of fourth pair of pulleys is operatively coupled with one of the second pair of camshafts 401, 402.
Taking into consideration the aforementioned Figures 3 and 4, it can be identified that the second actuating rod 410 is constrained around a second rod rotation axis interposed between the third pulley rotation axis and the fourth pulley rotation axis. The distance D4 between the third pulley rotation axis and the fourth pulley rotation axis is lower than the sum of the major radii of the third pairs of cams and fourth pair of cams.
As described above, the locking device 100, i.e. the locking disc 110, has the function of allowing the axial movement of the corresponding valve 11 during the intake process for the intake valves or the exhaust process for the exhaust valves, of lock by means of the relative locking elements 114, 115, 116 the axial movement of the valve 11 during the compression and explosion process, of avoiding gas leaks from the combustion chamber and of withstanding the high pressures developed therein during the compression and explosion process.
In this regard, the second actuating rod 410 defines a semi-radial movement to allow the actuation of the locking disk 110. In the case of several intake or exhaust valves 11, as illustrated in Figures 3 and 4, the locking device 100, i.e. the locking disc 110, in contact with the second actuating rod 410 transmits its semi-radial movement to the other devices 100, or to the locking discs 110, by means of suitable gears (not shown) arranged on the respective contact surfaces. The locking device 100, or the related locking disc 110, is completely open just before the intake or exhaust valve 11 begins to move in the opposite direction to the piston head. The same locking device 100, or the related locking disc 110, begins its closing configuration immediately after the intake or exhaust valve 11 stops its movement towards the piston head. One of the cams of the fourth pair of cams, the one closest to the free end of the second actuating rod 410, controls the movement of the second actuating rod 410 by opening the locking device 100, or the locking disc 110, while one of the cams of the third pair of cams, the one furthest away from the free end of the second actuating rod 410, has the function of not allowing free movements of the same second actuating rod 410 during the opening process of the locking device 100, or of the locking disc 110. The other cam of the third pair of cams provides for the semi-radial movement for closing the locking device 100, or rather of the locking disc 110, while the other cam of the fourth pair of cams has the function of not allowing free movements of the second actuating rod 410 during the closing process of the locking device 100, or rather of the locking disc 110.
The ratio between the distance of the end of the second actuating rod 410 in contact with the locking device 100, or with the locking disc 110, and the rotation axis of the same second actuating rod 410 and the distance of this rotation axis from the common axis of the fourth pair of pulleys must be as large as possible so as to minimize the intermediate opening and closing cycles of the locking device 100 using a small lift of the cams. As described above for the first pair of camshafts, it is possible to use very curved profiles both on the part of the cam responsible for the intermediate short opening cycle of the locking device 100 and on the part of the cam responsible for the intermediate short closing cycle considering that the force required for the movement of the locking device 100 is very low due to the very low mass of the locking device 100. The intermediate short closing cycle of the locking device 100 is also possible considering that the resistance torque on the valve axis locking device 100 which is present only at the end of the valve block closing is very low in consideration of the choice of the aforementioned geometries of the second actuating rod 410, of the geometries of the head 110 of the valve 11 and of the geometries of the respective locking elements 114, 115, 116 and project 311, 411, 511.
Therefore, again as described above for the first actuating rod 210, in the construction of the apparatus 1 according to the present invention, the second actuating rod 410 as well as the corresponding third pair of pulleys and fourth pair of pulleys, the respective third pair of cams and fourth pair of cams in contact with them and the second pair of camshafts support at least the torque on the locking device 100, i.e. on the locking disc 110, generated by the pressure developed in the combustion chamber during the explosion and compression process. Considering that the aforementioned torque is reduced, the weight considerations already expressed above can be applied.
The present invention therefore allows the drawbacks of valve control systems for combustion engines of the known type to be obviated. In particular, the present invention allows providing a maneuver apparatus for the intake and exhaust valve which allow a greater efficiency of fuel management at normal speeds, as well as the achievement of very high powers, torques and speeds of the combustion engine without a very consistent increase in fuel consumption. The apparatus according to the invention also allows defining much shorter intermediate opening and closing times of the valves, longer and much more efficient intake and exhaust processes compared to known valve control systems. The high efficiency of the suction and discharge process of the apparatus according to the invention is also guaranteed by a non-obstructive position of the valves during these processes.

Claims

Claims
1. A maneuver apparatus (1) for intake and exhaust valves comprising at least an intake and/or exhaust valve (11) and maneuvering means of said valves, wherein each of said valves (11) comprise a head (111) and a stem (200), said stem (200) being operatively coupled to said maneuvering means, and wherein said maneuvering means are able to move said valve (11) between a first working position, in which said valve (11) is arranged at the related valve seat (50), and a second working position, in which said valve (11) is spaced apart from said valve seat (50), and vice-versa, along the axial direction of the symmetry axis (A) of said stem (200), said maneuver apparatus (1) is characterized in that said valve (11) is arranged outside of the cylinder head and comprises at least a projection (311, 411, 511) which protrudes from said stem (200) and substantially perpendicular to said symmetry axis (A), wherein said maneuver apparatus (1) comprises a locking device (100) provided with at least a locking element (114, 115, 116) capable to be operatively coupled to said projection (311, 411, 511), and wherein said maneuvering means are operatively coupled to said locking device (100) and are able to move said locking device (100) from a locking position, in which said locking element (114, 115, 116) is at least partly engaged with said projection (311, 411, 511) avoiding the movement of said valve (11) along said axial direction, to an unlocking position, in which said locking element (114, 115, 116) is disengaged from said projection (311, 411, 511) allowing the movement of said valve (11) along said axial direction, and vice-versa.
2. Maneuver apparatus (1) for intake and exhaust valves according to claim 1, wherein said maneuvering means moves said valve (11) along said axial direction in a synchronized manner with said movement of said locking element (100) between a said first working position, when said locking element (114, 115, 116) is in said locking position, and said second working position, when said locking element (114, 115, 116) is in said unlocking position, and vice-versa.
3. Maneuver apparatus (1) for intake and exhaust valves according to claim 2, wherein said maneuvering means comprise a first pair of counter-rotating camshafts (201, 202), respectively provided with a first pair of cams (211, 221) and with a second pair of cams (212, 222), and a first actuating rod (210) operatively connected to said first pair of camshafts (201, 202), at a first portion, and to said stem (200), at a second portion opposite to said first portion, wherein said first actuating rod (210) is provided with a first pair of pulleys (231, 241) and with a second pair of pulleys (232, 242) arranged at said first portion, each of said first pair of pulleys (231, 241) and second pair of pulleys (232, 242) being aligned and concentric respectively to a first pulley rotation axis and to a second pulley rotation axis on opposite sides of said first actuating rod (210), and each of said first pair of pulleys (231, 241) and second pair of pulleys (232, 242) being operatively coupled to one of said first pair of camshafts (201, 202), wherein said first actuating rod (210) is constrained with respect to a first rod rotation axis interposed between said first pulley rotation axis and said second pulley rotation axis, and wherein the distance (Dl) between said first pulley rotation axis and said second pulley rotation axis is lower than the sum of the major radii (D2, D3) of said first pairs of cams (211, 221) and second pair of cams (212, 222).
4. Maneuver apparatus (1) for intake and exhaust valves according to one of claims 1-3, wherein said maneuver apparatus (1) comprises a centering element (500) provided with an opening operatively coupled with at least a sliding portion (21 G) of said stem (200) and able to allow the movement of said valve (11) between said first working position and said second working position along the axial direction of the symmetry axis of said stem (200), and wherein said opening and said sliding portion (21 G) have a have a section perpendicular to said symmetry axis with a conformation different from the cylindrical one to prevent rotation of said sliding portion (21 G).
5. Maneuver apparatus (1) for intake and exhaust valves according to one of claims 1-4, wherein said stem (200) comprises a plurality of projections (311, 411, 511) equidistant arranged radially with respect to said symmetry axis (A), wherein said locking device (100) comprises a locking disc (110) arranged concentric with respect to said stem (200) and provided with a plurality of unlocking openings (111,
112, 113) equidistant arranged radially with respect to said symmetry axis (A) and with a plurality of said locking elements (114, 115, 116) each respectively interposed between two successive unlocking openings (111, 112, 113), and wherein said maneuvering means are able to rotate said locking disc (110) with respect to said stem (200) from said locking position, wherein said locking elements (114, 115,
116) are arranged at said projections (311, 411, 511) to avoid the movement of said valve (11) along said axial direction, to said unlocking position, wherein said unlocking openings (111, 112, 113) are arranged at said projections (311, 411, 511) to allow the movement of said valve (11) along said axial direction, and vice-versa.
6. Maneuver apparatus (1) for intake and exhaust valves according to claim 5, wherein said projections (311, 411, 511) have a first sloping surface (1311) between two opposite ends, wherein said locking elements (114, 115, 116) have a second sloping surface (1114) between two opposite ends, and wherein said first sloping surface (1311) and said second sloping surface (1114) are arranged facing to each other and have shape such as to fit together.
7. Maneuver apparatus (1) for intake and exhaust valves according to claim 5 or 6, wherein said maneuvering means comprise a second pair of counter-rotating camshafts (401, 402), respectively provided with a third pair of cams and with a fourth pair of cams, and a second actuating rod (410) operatively connected to said second pair of camshafts (401, 402), at a first portion, and to said locking disc (110), at a second portion opposite to said first portion, wherein said second actuating rod (410) is provided with a third pair of pulleys and of a fourth pair of pulleys arranged at said first portion, each of said third pair of pulleys and fourth pair of pulleys being aligned and concentric respectively to a third pulley rotation axis and to a fourth pulley rotation axis on opposite sides of said second actuating rod, and each of said third pair of pulleys and of said fourth pair of pulleys being operatively coupled with one of said second pair of camshafts (401, 402), wherein said second actuating rod (410) is constrained with respect to a second rod rotation axis interposed between said third pulley rotation axis and said fourth pulley rotation axis, and wherein the distance between said third pulley rotation axis and said fourth pulley rotation axis is lower than the sum of the major radii of said third pairs of cams and fourth pair of cams.
8. Maneuver apparatus (1) for intake and exhaust valves according to claims 3 and 7, wherein said first pair of camshafts (201, 202) and said second pair of camshafts (401, 402) have the same modulus of rotation speed.
9. A vehicle comprising an internal combustion engine comprising a maneuver apparatus (1) for intake and exhaust valves according to one of claims 1-8.
10. An electric generator comprising an internal combustion engine comprising a maneuver apparatus (1) for intake and exhaust valves according to one of claims 1-8.
PCT/IB2022/057116 2021-09-01 2022-08-01 Control of valves with locking system in internal combustion engines WO2022224233A2 (en)

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DE3926809A1 (en) * 1989-08-14 1991-02-21 Kriegler Franz Damping arrangement for valves in IC engine - makes use of conical bodies to avoid need for anti-knock agents
DE3926804A1 (en) * 1989-08-14 1991-02-21 Kriegler Franz Valve drive for IC engine - makes use of spring-loaded buffer and positive connection drive
BRPI0811935A2 (en) * 2007-08-07 2014-11-25 Scuderi Group Llc DIVIDED CYCLE MOTOR WITH A HELICAL PASSAGE CHANNEL
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