JP2007270795A - Lift variable valve gear of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance valve system control accuracy, by correcting an error in sensor output caused by a temperature change and the deterioration, in a lift variable valve gear of an internal combustion engine having a lift variable mechanism having a control shaft and capable of changing a lift quantity of an engine valve in response to the rotational movement of the control shaft, a sensor detecting a rotational quantity of the control shaft, and an actuator having an electric motor exhibiting motive power for rotatingly driving the control shaft while feeding back a detecting value of the sensor and installed on an outer wall of an engine body. <P>SOLUTION: This lift variable valve gear of the internal combustion engine is constituted so that a rotation regulating mechanism mechanically regulating a rotational range of the control shaft, is arranged between the control shaft and the engine body, and a control unit C controlling operation of the electric motor 62, learns output of the sensor 97 by setting a state of regulating the control shaft 61 to the unidirectional regulating end as an initial position by the rotation regulating means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a variable lift mechanism having a control shaft and capable of changing the lift amount of the engine valve in accordance with the rotation of the control shaft, a sensor for detecting the rotation amount of the control shaft, and the sensor The present invention relates to a variable lift valve operating apparatus for an internal combustion engine having an electric motor that exerts power for rotating the control shaft while feeding back the detected value of the engine, and an actuator attached to the outer wall of the engine body.

An actuator that has an electric motor that drives the control shaft and is attached to the engine body is attached to the outer wall of the engine body, and controls the operation amount of the electric motor by feeding back the detection value of the sensor that detects the rotation amount of the control shaft. Such an arrangement is already known, for example, from Patent Document 1.
Japanese Patent Laid-Open No. 2005-240615

  However, the variable lift valve operating device disclosed in Patent Document 1 cannot cope with an error in the sensor output due to the influence of temperature change, deterioration, or the like. Valve control accuracy decreases.

  The present invention has been made in view of such circumstances, and provides a variable lift valve operating system for an internal combustion engine that can correct a sensor output error due to a temperature change, deterioration, or the like to improve valve control accuracy. The purpose is to provide.

  In order to achieve the above object, the invention according to claim 1 has a control shaft and a variable lift mechanism capable of changing a lift amount of the engine valve in accordance with the rotation of the control shaft, and the control. An internal combustion engine comprising: a sensor for detecting a rotation amount of the shaft; and an actuator attached to an outer wall of the engine body having an electric motor that exerts power for rotating the control shaft while feeding back a detection value of the sensor In the variable lift valve operating apparatus, a rotation restricting mechanism for mechanically restricting a rotation range of the control shaft is provided between the control shaft and the engine body, and a control unit for controlling the operation of the electric motor includes: State where the control shaft is restricted to the one-way restriction end by the rotation restriction mechanism Characterized by learning the output of the sensor as the initial position.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the control unit is configured to rotate the control shaft to the one-way restriction end by the turning restriction mechanism when starting the internal combustion engine. An electric motor is operated, and the learning is executed at that time.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, when the control unit restricts the control shaft to a one-way restricting end by the rotation restricting mechanism, the electric motor is provided. It is characterized in that the operation of is made gentler than at other times.

  Furthermore, in addition to the structure of the invention according to any one of claims 1 to 3, the rotation restricting mechanism includes a restricting pin protruding from the control shaft and an insert of the restricting pin. And an arc-shaped restricting hole centered on the axis of the control shaft, and the restricting hole is disposed below the bearing portion of the control shaft.

  The intake valve 20 of the embodiment corresponds to the “engine valve” of the present invention.

  According to the first aspect of the present invention, the output of the sensor is obtained with the state where the rotation position of the control shaft is restricted to the one-way restriction end by the rotation restriction mechanism that mechanically restricts the rotation range of the control shaft. By learning, the sensor output can be corrected according to the deviation of the predetermined value such as temperature change or deterioration, and the error of the sensor output due to temperature change or deterioration can be corrected to improve the valve control accuracy. it can.

  Further, according to the invention described in claim 2, it is possible to correct the sensor output each time the internal combustion engine is started and to execute more accurate valve control.

  According to the invention described in claim 3, it is possible to reduce the impact when mechanically restricting the control shaft to the one-way restricting end, thereby enhancing durability.

  According to the fourth aspect of the present invention, oil that lubricates the bearing portion of the control shaft can easily flow into the lower restriction hole, and the sliding resistance when the restriction pin moves can be reduced. It can contribute to improvement of the property.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 11 show an embodiment of the present invention. FIG. 1 is a partial longitudinal sectional view of an internal combustion engine, taken along line 1-1 of FIG. 2, and FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2, FIG. 4 is an enlarged view of the main part of FIG. 1, FIG. 5 is a bottom view of the intake side rocker arm as viewed from the direction of arrow 5 in FIG. 7 is a perspective view of the lift variable mechanism, FIG. 8 is a sectional view taken along the line 8-8 in FIG. 4, FIG. 9 is a sectional view taken along the line 9-9 in FIG. 2, and FIG. FIG. 11 is a block diagram showing a control system.

  In FIG. 1, an engine body 11 of an internal combustion engine E, which is an in-line multi-cylinder, includes a cylinder block 13 having cylinder bores 12 provided therein, a cylinder head 14 coupled to the top surface of the cylinder block 13, and a cylinder head. 14, a head cover 15 coupled to the top surface of each of the cylinders 14. A piston 16 is slidably fitted to each cylinder bore 12, and a combustion chamber 17... Facing the top of each piston 16. It is formed between the cylinder heads 14.

  The cylinder head 14 is provided with intake ports 18 and exhaust ports 19 that can communicate with the combustion chambers 17. The intake ports 18 are opened and closed by intake valves 20 that are a pair of engine valves. Each exhaust port 19 is opened and closed by a pair of exhaust valves 21. Between the spring seat 22 and the cylinder head 14 provided at the upper end portion of the stem 20a provided in the intake valve 20, a valve spring 23 for urging each intake valve 20 in the valve closing direction is provided. Further, between the spring seat 24 and the cylinder head 14 provided at the upper end portion of the stem 21 a provided in the exhaust valve 21, a valve spring 25 that urges each exhaust valve 21 in the valve closing direction is provided.

  The intake side valve operating device 28 that opens and closes each intake valve 20 is configured according to the present invention, and includes an intake side camshaft 30 having an intake side valve cam 29 for each cylinder, and an intake side valve control. Each cylinder is provided with an intake-side rocker arm 31 and a lift variable mechanism 32 that are linked to and coupled to a pair of intake valves 20... The exhaust side valve operating device 33 that opens and closes 21... Is driven by an exhaust side camshaft 35 having an exhaust side valve cam 34 for each cylinder and the exhaust side valve cam 34 and swings for each cylinder. And an exhaust-side rocker arm 36 that is linked and connected in common to the pair of exhaust valves 21.

  Referring to FIGS. 2 and 3 together, upper holders 38 and 37 are fastened to the cylinder head 14 so as to be arranged on both sides of each cylinder. Are fastened from above by caps 39, 40, which cooperate with the intake side cam holders 41 and the exhaust side cam holders 42, respectively. Thus, the upper holders 38 constituting the intake side cam holders 39 ..., the holder 37 and the cap 39 are rotatably supported by the intake side camshaft 30, and the upper holders constituting the exhaust side cam holders 42 ... cooperatively. 38, between the holder 37 and the cap 40, the exhaust side camshaft 35 is rotatably supported.

  One end of the exhaust side rocker arm 36 is supported so as to be swingable by an exhaust side rocker shaft 43 having an axis parallel to the exhaust side camshaft 35 and supported by the upper holder 38. A pair of tappet screws 44, 44 that abut on the upper ends of the stems 21a of the pair of exhaust valves 21 are screwed to the other end so that the forward and backward positions can be adjusted. In addition, a shaft 45 parallel to the exhaust side rocker shaft 36 is provided at an intermediate portion of the exhaust side rocker arm 36, and a roller 47 that is in rolling contact with the exhaust side valve cam 34 is in contact with the shaft 45. Is pivotally supported by the exhaust-side rocker arm 36.

  Such an exhaust side valve operating device 33 is configured such that the rocking support portion of the exhaust side rocker arm 36, that is, the exhaust side rocker shaft 43 is linked to the exhaust valve 21 of the exhaust side rocker arm 36, and the connecting portion, that is, the tappet screw 44. Are also arranged on the cylinder head 14 so as to be arranged outside.

  4 and 5, tappet screws 49, 49 that are in contact with the upper ends of the stems 20a of the pair of intake valves 20 from above are screwed into one end of the intake side rocker arm 31 so that the forward and backward positions can be adjusted. A valve connection part 31a is provided. The other end portion of the intake side rocker arm 31 is provided with a first support portion 31b and a second support portion 31c disposed below the first support portion 31b so as to be connected to each other. The portions 31b and 31c are formed in a substantially U shape that opens on the opposite side to the intake valves 20.

  The first support portion 31 b of the intake side rocker arm 31 is provided with a roller 50 as a cam contact portion that is in rolling contact with the intake side valve cam 29 of the intake side camshaft 30 via a first connecting shaft 51 and a roller bearing 52. The roller 50 is pivotally supported, and is disposed so as to be sandwiched between first U-shaped first support portions 31b.

  Referring also to FIG. 6, the intake side rocker arm 31 is molded by light alloy casting or the like, and has, for example, a substantially triangular hollow portion 53 at the center of the upper surface of the valve connecting portion 31 a. A pair of lightening portions 54, 54 are formed on both sides of the lower surface of the valve coupling portion 31a, which is the surface opposite to the upper surface, so as to be arranged alternately with the lightening portions 53. The

  By the way, the said thinning part 53,54,54 is shape | molded simultaneously with the shaping | molding of the intake side rocker arm 31, and a thinning part is formed as the draft of the upper thinning part 53 goes to the upper surface of the valve connection part 31a. 53 is a direction to widen the opening area, whereas the draft angle of the lower lightening portions 54, 54 is a direction to increase the opening area of the lightening portions 54, 54 toward the lower surface of the valve connecting portion 31a. The inclination direction of the inner surface of the lightening portion 53 is the same as the inclination direction of the inner surface of the lightening portions 54, 54, and the valve connecting portion 31 a is between the lightening portions 53, 54; 53, 54 adjacent to each other. The thicknesses of the wall portions 31d and 31d formed in are substantially uniform.

  Referring to FIGS. 7 and 8 together, the variable lift mechanism 32 has one end portion rotatably connected to the first support portion 31 b of the intake side rocker arm 31 and the other end portion fixed to the engine body 11. A first link arm 58 that is rotatably supported at a position via an intake side rocker shaft 57, and a second link arm whose one end portion is rotatably connected to the second support portion 31c of the intake side rocker arm 31. 59, a movable support shaft 60 that rotatably supports the other end of the second link arm 59, and a movable support shaft 60 that can angularly displace the movable support shaft 60 about an axis parallel to the axis. And a control shaft 61 coupled to the.

  One end portion of the first link arm 58 is formed in a substantially U shape so as to sandwich the first support portion 31b of the intake side rocker arm 31 from both sides, and a first connection that pivotally supports the roller 50 on the intake side rocker arm 31. The shaft 51 is rotatably connected to the first support portion 31b. Further, the intake side rocker shaft 57 that rotatably supports the other end portion of the first link arm 58 is supported by the upper holder 38 ... and the holder 37 that are fastened to the cylinder head 14.

  One end portion of the second link arm 59 disposed below the first link arm 58 is disposed so as to be sandwiched between the second support portions 31 c of the intake side rocker arm 31, and is second supported via the second connecting shaft 63. The part 31c is pivotally connected.

  Support bosses 64 are integrally projected on the upper holder 38 and the holder 37 on both sides of the other end of the first link arm 58 so as to support the intake side rocker shaft 57. Thus, the movement of the other end portion of the first link arm 58 in the direction along the axis of the intake rocker shaft 57 is restricted.

  The two intake valves 20 are spring-biased by the valve springs 23 in the valve closing direction, and the two intake valves 20 that are spring-biased in the valve closing direction are opened by the intake side rocker arm 31 in the valve opening direction. The roller 50 of the intake-side rocker arm 31 is in contact with the intake-side valve cam 29 by the action of the valve springs 23 when the intake valve 20 is closed. The spring force of... Does not act on the intake side rocker arm 31, and the roller 50 moves away from the intake side valve cam 29, and the control accuracy of the valve lift amount when the intake valve 20. There is a possibility that. Accordingly, the intake side rocker arm 31 is biased in a direction in which the roller 50 is brought into contact with the intake side valve cam 29 by a rocker arm biasing spring 65 different from the valve springs 23.

  The rocker arm biasing springs 65 are coiled torsion springs surrounding the support bosses 64 and are provided between the engine body 11 and the intake side rocker arm 31. That is, one end of the rocker arm urging spring 65 is engaged with the support boss 64, and the other end of the rocker arm urging spring 65 is inserted into the hollow first connecting shaft 51 that operates integrally with the intake side rocker arm 31. Engaged.

  The other end portion of the first link arm 58 is formed in a cylindrical shape so that the outer periphery is arranged inwardly in a side view rather than the outer periphery of the rocker arm biasing spring 65 wound in a coil shape. A plurality of, for example, a pair of protrusions 66 and 67 for preventing the rocker arm urging springs 65 from falling to the first link arm 58 side are provided at both ends in the axial direction at the other end of the first link arm 58. Projections are provided at intervals in the direction. Therefore, while preventing the other end portion of the first link arm 58 from increasing in size, the rocker arm biasing springs 65 can be prevented from falling and the support rigidity of the other end portion of the first link arm 58 can be increased. .

  Moreover, the protrusions 66 and 67 are arranged so as to avoid the operating range of the second link arm 59, and the protrusions 66, 67... Are provided at the other end of the first link arm 58. The operating range of the second link arm 59 can be sufficiently secured.

  Oil jets 68 for supplying oil toward the upper part on the other end side of the intake side rocker arm 31 are attached to the caps 39 of the intake cam holders 41 provided on the engine body 11.

  Incidentally, one of the plurality of upper holders 38... And the holder 37 is provided with a passage 69 for guiding oil from an oil pump (not shown). Further, each upper holder 38... And the upper portion of the holder 37 are provided with arc-shaped concave portions 70... Facing the lower half of the intake side camshaft 30, and the passage 69 is one of the respective concave portions 70. Communicate with. On the other hand, the intake-side camshaft 30 is provided with an oil passage 71 coaxially, and the intake-side camshaft 30 is connected to the intake-side camshaft 30 at the portion corresponding to each intake-side cam holder 41. Holes 72 are provided so that the outer ends thereof are opened on the outer surface of the intake side camshaft 30. Between the intake side cam holders 41 and the camshaft 30, the communicating holes 72 are used for lubrication. Of oil is supplied.

  Further, on the lower surface of the caps 39 that constitute the intake side cam holder 41 together with the upper holders 38 and 37, a recess 73 that forms a passage leading to the recesses 70 between the upper holder 38 and the upper surface of the holder 37 is formed. Are provided, and oil jets 68 are attached to the caps 39 so as to be continuous with the passages 74 provided in the caps 39 through the recesses 73.

  The oil jets 68 are attached to the caps 39 of the intake cam holders 46 provided in the engine body 11 so as to rotatably support the intake side camshaft 30 in this way, and therefore the intake side camshaft 30 and the intake side cam holder 41... Can be supplied from the oil jet 68 with a sufficiently high pressure and a sufficient amount of oil by utilizing an oil passage for lubricating the space 41.

  Further, the oil jet 68 supplies oil to the upper first connecting shaft 51 side of the first and second connecting shafts 51 and 63 that connect one end portions of the first and second link arms 58 and 59 to the intake side rocker arm 31. Therefore, the oil lubricated between the first link arm 58 and the intake side rocker arm 31 flows down to the second link arm 59 side below.

  In addition, the oil introduction holes 75 and 76 that allow a part of the movable support shaft 60 and the second connection shaft 63 to face the intermediate portion are second in the direction orthogonal to the straight line connecting the axes of the movable support shaft 60 and the second connection shaft 63. Provided in the link arm 59, one end of each oil introduction hole 75, 76 opens toward the first connecting shaft 51 side. Accordingly, the oil that has flowed downward from the first link arm 58 is effectively guided between the second link arm 59 and the movable support shaft 60 and the second connecting shaft 63, which is simple and reduces the number of parts. With the lubrication structure, the connecting portion between the intake side rocker arm 31 and the first and second link arms 58 and 59 and the space between the second link arm 59 and the movable support shaft 60 are both lubricated to ensure smooth valve operation. can do.

  The control shaft 61 is a single shaft that is supported by the engine body 11 in common for a plurality of cylinders arranged in a row, and includes webs 61a and 61a disposed on both sides of the intake-side rocker arm 31 and the bases of both webs 61a and 61a. Each cylinder has a journal portion 61b, 61b that is connected to the outer surface of the end portion at a right angle and is rotatably supported on the engine body 11, and a connecting portion 61c that connects the webs 61a, 61a. Is done.

  The control shaft 61 is arranged so that at least a part thereof, that is, a part of the web 61a in this embodiment overlaps the second link arm 58 when viewed from the direction along the axis of rotation, that is, the axis of the journal portion 61b. The movable support shaft 60 is connected to the control shaft 61 so as to connect the webs 61a and 61a.

  Each journal portion 61b of the control shaft 61 has an upper holder 38 'connected to the cylinder head 14 of the engine body 11 and other upper holders 38' other than the holder 37 on one end side in the axial direction of the control shaft 61 of the holder 37. .. And a lower holder 77 (see FIGS. 1 and 4) coupled to the upper holder 38 from below, and is rotatably supported by the holder 37. The lower holders 77 are formed separately from the cylinder head 14 so as to be fastened to the upper holders 38.

  In addition, roller bearings 79 are interposed between the upper and lower holders 38, 77, and the journal portions 61b, and the roller bearings 79 are connected to a plurality of webs 61a, 61a, and the connection. Since it is interposed between the journal portions 61b of the control shaft 61 having a portion 61c, which is common to a plurality of cylinders, and the upper and lower holders 38, 77,.

  By the way, the upper and lower holders 38, 77, and 37 and the holder 37 are formed with control shaft support boss portions 80 projecting toward the web 61a of the control shaft 61 so as to penetrate the journal portion 61a. . On the other hand, upper shaft holders 38, 37, and caps 39, which are coupled to each other to form the intake side cam holders 41 in cooperation, are camshaft support boss portions 81 that allow the intake side camshaft 30 to pass therethrough. Are formed so as to protrude toward the intake side rocker arms 31... And the upper holder 38... And the holder 37 are ribs connecting the control shaft support boss portions 80 and the camshaft support boss portions 81. 82... Project integrally.

  In the ribs 82, passages 83 for guiding oil to the roller bearings 79 are provided so as to communicate with the recesses 70 on the upper surfaces of the upper holders 38, 38 '.

  By the way, the exhaust side valve operating device 33 is arranged in the cylinder head 14 so that the swing support portion of the exhaust side rocker arm 36 is arranged outside the interlocking and connecting portion to the exhaust valve 21 of the exhaust side rocker arm 36. On the other hand, in the intake side valve operating device 28, the intake side rocker shaft 57 and the movable support shaft 60 are arranged on the inner side of the interlocking and connecting portion of the intake side rocker arm 31 to the intake valve 20. In this manner, the cylinder head 14 is disposed.

  In addition, a plug cylinder 87 into which a spark plug 86 attached to the cylinder head 14 is inserted so as to face the combustion chamber 17 is attached to the cylinder head 14 between the intake side and exhaust side valve devices 28, 33. The cylinder 87 is arranged so as to be inclined so as to approach the exhaust side valve operating apparatus 33 as it goes upward.

  Thus, the control shaft 61 in the intake side valve operating device 28 is disposed between the intake valves 20 and the plug cylinders 87 so that the connecting portions 61c are opposed to the plug cylinders 87. However, relief grooves 88 for avoiding interference with the plug cylinders 87 are formed on the outer surface of the connecting portions 61c.

  By the way, the second connecting shaft 63 that connects the second link arm 59 to the intake side rocker arm 31 when the intake valves 20 are closed is coaxial with the journal portion 61b of the control shaft 61. Oscillates around the axis of the journal portion 61b..., The movable support shaft 60 moves on an arc centered on the axis of the journal portion 61b.

  As clearly shown in FIG. 3, a journal portion 61 b of the control shaft 61 is inserted through a roller bearing 79 into the lower portion of the holder 37 that rotatably supports the control shaft 61 on one end side in the axial direction of the control shaft 61. A support hole 110 is provided for support.

  On the other hand, a rotation restricting mechanism 111 that mechanically restricts the rotation range of the control shaft 61 is provided between the control shaft 61 and the holder 37 on the engine body 11 side. The control shaft 61 includes a restriction pin 112 projecting from the web 61a facing the holder 37 to the holder 37 side, and a restriction hole 113 provided in the holder 37 for inserting the restriction pin 112. 113 is formed in an arc shape centered on the rotation axis of the control shaft 61, that is, the axis of the journal portion 61 b, so that a vertical axis passing through the rotation axis of the control shaft 61 passes somewhere in the restriction hole 113. The control shaft 61 is disposed below the bearing portion.

  Thus, the oil that lubricates the bearing portion of the control shaft 61 easily flows into the lower restriction hole 113, and can reduce the sliding resistance when the restriction pin 112 moves, contributing to the improvement of the response of the control shaft 61. can do. Further, since the restriction hole 113 is provided in the highly rigid holder 37, the stable operation of the restriction pin 112 can be ensured.

  9 and 10, one of the journal portions 61 b... Provided in the control shaft 61 protrudes from a support hole 89 provided in the head cover 15, and this journal portion 61 b is driven by the actuator 115. That is, the rotation restricting mechanism 111 is provided between the holder 37 closest to the actuator 115 and the control shaft 61, and the influence of the twist of the control shaft 61 on the rotation restricting mechanism 11 can be reduced.

  The actuator 115 includes a control arm 91 whose base end is fixed to the distal end of the journal portion 61b, and an electric motor 62 as a drive source that exerts power for rotationally driving the control arm 91.

  A nut member 93 is engaged with a screw shaft 92 rotated by the electric motor 62, and the other end of the connection link 95 pivotally supported at one end by a pin 94 on the nut member 93 is connected to a control arm 91 via pins 96, 96. Connected to Therefore, when the electric motor 62 is operated, the nut member 93 moves along the rotating screw shaft 92 and is controlled around the axis of the journal portion 61b... By the control arm 91 connected to the nut member 93 via the connecting link 95. When the shaft 61 swings, the movable support shaft 60 is displaced.

  A sensor 97 such as a rotary encoder is provided on the outer wall surface of the head cover 15, and one end of the sensor arm 98 is fixed to the tip of the sensor shaft 97a. A guide groove 99 extending linearly along the longitudinal direction is formed in the control arm 91, and a connecting shaft 100 provided at the other end of the sensor arm 98 is slidably fitted in the guide groove 99. .

  The screw shaft 92, the nut member 93, the pin 94, the connection link 95, the pins 96 and 96, the control arm 91, the rotation angle sensor 97, the sensor arm 98 and the connection shaft 100 are bolts 102 on the side surfaces of the cylinder head 14 and the head cover 15. And a cover 103 that covers the open end surface of the case 101 is attached to the case 101 with screw members 104.

  In the variable lift mechanism 32, when the control arm 91 is rotated counterclockwise from the position shown in FIG. 9 by the electric motor 62, the control shaft 61 connected to the control arm 91 is also rotated counterclockwise to move the movable support. The shaft 60 is lowered. When the roller 50 is pressed by the intake side valve cam 29 of the intake side camshaft 30 in this state, the four nodes connecting the intake side rocker shaft 57, the first connecting shaft 51, the second connecting shaft 63, and the movable support shaft 60 are connected. The link is deformed and the intake side rocker arm 31 swings downward, the tappet screws 49 and 49 press the stem 20a of the intake valve 20, and the intake valve 20 is opened with a low lift.

  When the control arm 91 is rotated to the solid line position in FIG. 9 by the electric motor 62, the control shaft 61 connected to the control arm 91 is rotated clockwise, and the movable support shaft 60 is raised. In this state, when the roller 50 is pressed by the intake side valve cam 29 of the intake camshaft 30, the four-bar link is deformed, the intake side rocker arm 31 swings downward, and the tappet screws 49, 49 are connected to the intake valve. 20 ... stems 20a are pressed and intake valves 20 ... are opened with high lift.

  The output of the sensor 97 is input to the control unit C as shown in FIG. 11, and the control unit C controls the operation amount of the electric motor 62 while feeding back the detection value of the sensor 97.

  Moreover, the control unit C learns the output of the sensor 97 with the state where the control shaft 61 is restricted to the one-way restriction end by the rotation restriction mechanism 111 as an initial position, and the rotation restriction mechanism when the internal combustion engine is started. In 111, the electric motor 62 is operated until the control shaft 61 is rotated to the one-way regulating end, and the learning is executed at that time.

  Further, the control unit C makes the operation of the electric motor 62 gentler than other times when the rotation restriction mechanism 111 restricts the control shaft 61 to the one-way restriction end.

  Next, the operation of this embodiment will be described. In the variable lift mechanism 32 for continuously changing the opening lift amount of the intake valves 20..., One end of the first and second link arms 58 and 59 is a pair. The other end of the first link arm 58 is supported by the engine body 11 in parallel with the intake side rocker arm 31 having a valve connecting portion 31a linked and connected to the intake valves 20. The second link arm 59 is rotatably supported by a movable movable shaft 60 that is displaceable by the intake side rocker shaft 57.

  Therefore, the lift amount of the intake valves 20 can be changed steplessly by displacing the movable support shaft 60 steplessly, and the intake amount can be controlled without using a throttle valve. In addition, one end portions of the first and second link arms 58 and 59 are directly connected to the intake side rocker arm 31 so as to be rotatable, so that the space for disposing both the link arms 58 and 59 is reduced and the valve operating device is made compact. Since the power from the intake side valve cam 29 is directly transmitted to the roller 50 of the intake side rocker arm 31, excellent followability to the intake side valve cam 29 can be secured. Further, the positions of the intake side rocker arm 31 and the first and second link arms 58 and 59 in the direction along the axis of the intake side camshaft 30 can be arranged at substantially the same position, and the axis of the intake side camshaft 31 is aligned. The intake side valve operating device 28 in the direction can be made compact.

  One end of the first link arm 58 is rotatably connected to the intake side rocker arm 31 via the first connection shaft 51, and the roller 50 is pivotally supported on the intake side rocker arm 31 via the first connection shaft 51. Therefore, it is possible to achieve the pivotable connection of the one end portion of the first link arm 58 to the intake side rocker arm 31 and the pivotal support of the roller 50 to the intake side rocker arm 31 with the common first connection shaft 51. Thus, the number of parts can be reduced and the intake side valve operating device 28 can be made more compact.

  In the intake side valve operating device 28 including the link variable mechanism 32 among the intake side and exhaust side valve operating devices 28 and 33, the intake side rocker shaft 57 and the movable support shaft 60 are connected to the intake valves 20 of the intake side rocker arm 31. The swinging support portion of the exhaust side rocker arm 36 provided in the exhaust side valve operating device 33 is disposed inside the interlocking and connecting portion, and is disposed outside the interlocking and connecting portion of the exhaust side rocker arm 36 and the exhaust valve 21. Therefore, even if the sandwiching angle α (see FIG. 1) of the intake valves 20... And the exhaust valves 21. However, mutual interference between the intake side and exhaust side valve operating devices 28 and 33 can be avoided.

  The exhaust side valve operating device 33 is connected to the engine body 11 via an exhaust side camshaft 35 having an exhaust side valve cam 34 and an exhaust side rocker shaft 43 so as to be swung by being driven by the exhaust side valve cam 35. A plug cylinder 68 provided between the intake side and the exhaust side valve operating devices 28 and 33 is provided with an exhaust side rocker arm 36 which is supported so as to be swingable and is linked to and connected to the exhaust valves 21. Accordingly, the plug cylinder 68 is disposed so as to avoid interference with the intake side and exhaust side valve operating devices 28 and 33 because it is attached to the cylinder head 14 so as to be closer to the exhaust side valve operating device 33. Thus, it is possible to contribute to further downsizing of the entire cylinder head 14.

  By the way, in the variable link mechanism 32 of the intake side valve operating device 28, the control shaft 61 to which the movable support shaft 60 is connected is configured in a crank shape. The control shaft 61 is made compact after the control shaft 61 is made compact. This makes it possible to precisely control the lift amount of the intake valves 20. In addition, the control shaft 61 includes webs 61a, 61a disposed on both sides of the intake side rocker arm 31, and a journal portion that is rotatably supported by the engine body 11 in a manner perpendicular to the outer surface of the base end of both webs 61a, 61a. 61b, 61b and a connecting portion 61c connecting both webs 61a, 61a are formed in a crank shape, and the movable support shaft 60 is connected to the control shaft 61 so as to connect both webs 61a, 61a. Therefore, the connection strength of the movable support shaft 60 to the control shaft 61 can be increased. Further, the control shaft 61 is supported by the engine body 11 on both sides of the intake side rocker arm 31, and the support rigidity of the control shaft 61 is further enhanced by supporting both ends, and the variable amount control of the lift amount of the intake valve 20 is more precise. Can be performed.

  In addition, since the single control shaft 61 is supported by the engine body 11 in common to a plurality of cylinders arranged in a row, the number of parts can be prevented from increasing, and the internal combustion engine E can be made compact. In addition, since the second link arm 59 and the control shaft 61 are arranged so that at least a part of the second link arm 59 and the control shaft 61 overlap when viewed from the direction along the rotation axis of the control shaft 61, the lift amount of the intake valves 20 is variable. The lift variable mechanism 32 can be made compact.

  In addition, since the control unit C that controls the operation of the electric motor 62 learns the output of the sensor 97 with the rotation restriction mechanism 111 mechanically restricting the control shaft 61 to the one-way restriction end as the initial position, the temperature change The output of the sensor 97 can be corrected in accordance with the deviation of the predetermined value such as the deterioration and the deterioration, and the error of the output of the sensor 97 due to the temperature change and the deterioration can be corrected to improve the valve control accuracy.

  The control unit C operates the electric motor 62 until the control shaft 61 is turned to the one-way restriction end by the turning restriction mechanism 111 when the internal combustion engine E is started, and executes the learning at that time. The output of the sensor 97 is corrected each time the internal combustion engine E is started, and more accurate valve control can be executed.

  Furthermore, when the control unit C restricts the control shaft 61 to the one-way restricting end by the rotation restricting mechanism 111, the operation of the electric motor 62 is made slower than other times. It is possible to relieve the impact when mechanically restricting and improve durability.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

FIG. 3 is a partial longitudinal sectional view of the internal combustion engine, taken along line 1-1 of FIG. 2. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is a principal part enlarged view of FIG. It is the bottom view which looked at the intake side rocker arm from the 5th arrow direction of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a perspective view of a lift variable mechanism. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 4. It is a 9-9 line arrow directional view of FIG. It is the perspective view seen from the 10 arrow direction of FIG. It is a block diagram which shows a control system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Engine main body 20 ... Intake valve 32 which is an engine valve ... Lift variable mechanism 61 ... Control shaft 62 ... Electric motor 97 ... Sensor 111 ... Turning control mechanism 112- ..Regulation pin 113 ... regulation hole 115 ... actuator

Claims (4)

  A variable lift mechanism (32) having a control shaft (61) and capable of changing the lift amount of the engine valve (20) according to the rotation of the control shaft (61), and the control shaft (61) An engine main body having a sensor (97) for detecting the amount of rotation of the motor and an electric motor (62) that exerts power for rotating the control shaft (61) while feeding back the detection value of the sensor (97). In the lift variable valve operating apparatus for an internal combustion engine comprising an actuator (115) attached to the outer wall of (11), the rotation restricting mechanism (111) for mechanically restricting the rotation range of the control shaft (61) A control shaft (61) is provided between the engine body (11) and controls the operation of the electric motor (62). The internal combustion engine characterized in that the unit (C) learns the output of the sensor (97) with an initial position defined by the rotation restricting mechanism (111) restricting the control shaft (61) to a one-way restricting end. Engine lift variable valve gear.   The control unit (C) operates the electric motor (62) until the control shaft (61) is turned to the one-way restriction end by the turning restriction mechanism (111) when the internal combustion engine is started. 2. The lift variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the learning is executed.   When the control unit (C) restricts the control shaft (61) to a one-way restricting end by the rotation restricting mechanism (111), the operation of the electric motor (62) is more gradual than at other times. The lift variable valve operating apparatus for an internal combustion engine according to claim 1 or 2, characterized in that:   The rotation restricting mechanism (111) includes a restricting pin (112) projecting from the control shaft (61) and an axis of the control shaft (61) by inserting the restricting pin (112). It comprises an arc-shaped restriction hole (113), and the restriction hole (113) is disposed below the bearing portion of the control shaft (61). Variable lift valve operating system for internal combustion engine.

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