WO2011086702A1

WO2011086702A1 - Variable valve device of internal combustion engine

Info

Publication number: WO2011086702A1
Application number: PCT/JP2010/050508
Authority: WO
Inventors: 江崎　修一
Original assignee: トヨタ自動車株式会社
Priority date: 2010-01-18
Filing date: 2010-01-18
Publication date: 2011-07-21
Also published as: JPWO2011086702A1

Abstract

Provided is a variable valve device of an internal combustion engine, wherein the operation state of an intake valve can be changed to a valve halt state in which the closing of the intake valve is maintained, by continuously changing the lift and/or the working angle of the intake valve. The operation time required to shift the operation state from a valve working state in which the lift and/or the working angle of the intake valve is large, to the valve halt state can be preferably reduced. A swing arm (70) having a profile to be in contact with a second roller (76) is provided. A variable intake valve device (32) is configured so that the contact position of the second roller (76) on the profile of the swing arm (70) varies to change the lift and the working angle of the intake valve (28). The profile of the swing arm (70) is formed so that the operation state of the intake valve (28) is shifted to the valve halt state when the period for closing the intake valve (28) is within a predetermined range in the vicinity of the bottom dead point for sucking air.

Description

Variable valve operating device for internal combustion engine

This invention relates to a variable valve operating apparatus for an internal combustion engine.

Conventionally, for example, Patent Document 1 discloses a variable valve operating device capable of continuously changing a lift amount and / or an operating angle of a valve (hereinafter simply referred to as an “operating angle”). This conventional variable valve operating device is arranged between a drive cam and a valve, and is arranged between the drive cam and the swing arm. An intermediate member for transmitting force to the swing arm. The swing arm is provided with a slider surface that contacts the intermediate member at a position facing the drive cam. Further, the oscillating arm is provided with a lost motion part formed of a surface that is lower than a virtual extension line of the slider surface at the tip of the slider surface.

According to the above configuration, the intermediate member is displaced to a position where it comes into contact with the lost motion part by continuously changing the valve operating angle, and thereby the valve is stopped so that the valve is kept closed. It becomes possible to change the operation state of the valve to the state. More specifically, the conventional variable valve system is configured such that the valve operating angle is minimized at a position where the closing timing of the intake valve is approximately halfway between the intake top dead center and the intake bottom dead center. The valve stop state can be obtained by moving the intermediate member from the position where the minimum working angle is obtained to the position where it comes into contact with the lost motion section.
The applicant has recognized the following documents including the above-mentioned documents as related to the present invention.

Japanese Unexamined Patent Publication No. 2008-112458 Japanese Unexamined Patent Publication No. 2007-239551 Japanese Unexamined Patent Publication No. 2008-045460 Japanese Patent No. 3799944 Japanese Special Table 2004-521234

In the variable valve operating apparatus in which the valve operating angle can be continuously changed like the variable valve operating apparatus described in Patent Document 1 described above, in order to obtain the valve stop state, the valve operating angle is continuously set. By changing it, it is necessary to shift the operation state of the valve to the valve stop state. When the temperature of the catalyst is high when a fuel cut execution request is issued, it is preferable to quickly shut off fresh air flow into the catalyst in order to suppress deterioration of the noble metal contained in the catalyst. However, especially under conditions where fuel cut is required during deceleration, the engine speed is often high, and the valve operating angle is often controlled near the maximum operating angle. Therefore, when fuel cut is actually required under such circumstances, according to the configuration of the conventional variable valve operating apparatus, it takes a long time to shift the valve operating state to the valve stop state. .

The present invention has been made to solve the above-described problems, and by continuously changing the lift amount and / or the operating angle of the intake valve, the operation state of the intake valve is changed to the closed state of the intake valve. In the variable valve operating device that can be changed to the valve stop state maintained at a constant value, the operation time required for the transition from the valve operation state controlled so as to increase the lift amount and / or the operating angle of the intake valve to the valve stop state is reduced. It is an object of the present invention to provide a variable valve operating apparatus for an internal combustion engine that can be suitably shortened.

A first invention is a variable valve operating apparatus for an internal combustion engine,
A variable valve operating device capable of changing the operation state of the intake valve to a valve stop state in which the intake valve is maintained in a closed state by continuously changing the lift amount and / or the operating angle of the intake valve,
A variable member having a profile that contacts a mating member included in the variable valve operating device;
The variable valve operating device changes a lift amount and / or a working angle of the intake valve by changing a contact position of the counterpart member on the profile of the variable member,
The profile of the variable member is formed so that the operation state of the intake valve shifts to the valve stop state when the closing timing of the intake valve is within a predetermined range near the intake bottom dead center. It is characterized by.

The second invention is the first invention, wherein
The internal combustion engine provided with the variable valve operating device is one in which the closing timing of the intake valve is delayed from the intake bottom dead center,
The profile of the variable member indicates that the operation state of the intake valve shifts to the valve stop state when the intake valve is closed at a timing retarded from the intake bottom dead center within the predetermined range. It is formed as follows.

The third invention is the first or second invention, wherein
The variable member is a swinging member that is disposed between a cam that drives the intake valve and the intake valve and swings as the cam rotates,
The counterpart member is an intermediate member that is disposed between the cam and the swing member and transmits the acting force of the cam to the swing member through the profile.
The profile of the swing member includes a slide surface that contacts the intermediate member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and the swing surface with respect to the slide surface. A lost motion portion that is provided at a distal end portion of the moving member far from the swing center, and that contacts the intermediate member when the operation state of the intake valve is the valve stop state,
The lost motion part is formed in a planar shape.

Moreover, 4th invention is 1st or 2nd invention,
The counterpart member is a swinging member that is disposed between a cam that drives the intake valve and the intake valve and swings as the cam rotates,
The variable member is a cam member that regulates the posture of the swing member with the cam,
The profile of the cam member includes a first curve portion that contacts the swing member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and an operating state of the intake valve. A second curved portion that contacts the rocking member when the valve is in a stopped state, and a third curved portion interposed between the first curved portion and the second curved portion,
The third curved portion is formed so as to smoothly connect the first curved portion and the second curved portion.

The fifth invention is the first or second invention, wherein
The variable valve operating apparatus further includes a swinging member that is disposed between a cam that drives the intake valve and the intake valve, and that swings as the cam rotates.
The counterpart member is a control shaft that changes the posture of the swing member according to an axial position;
The variable member is a cam member that displaces the control shaft in the axial direction,
The profile of the cam member includes a first curve portion that contacts the swing member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and an operating state of the intake valve. A second curved portion that contacts the rocking member when the valve is in a stopped state, and a third curved portion interposed between the first curved portion and the second curved portion,
The third curved portion is formed so as to smoothly connect the first curved portion and the second curved portion.

According to the first invention, the profile of the variable member is formed so that the operating state of the intake valve shifts to the valve stop state when the closing timing of the intake valve is within a predetermined range near the intake bottom dead center. Yes. For this reason, the lift of the intake valve is higher than that of a conventional variable valve gear that is configured so that the valve stop state can be obtained at a position where the intake valve closes approximately halfway between the intake top dead center and the intake bottom dead center. It is possible to suitably shorten the operation time required for the transition from the valve operating state controlled to increase the amount and / or the operating angle to the valve stopped state. As a result, when a fuel cut is required, the flow of fresh air into the catalyst can be promptly blocked by stopping the valve, and the deterioration of the catalyst can be satisfactorily suppressed.

According to the second aspect of the present invention, in the configuration in which the variable valve gear of the present invention is applied to an internal combustion engine to which the slow closing Atkinson cycle is applied, the intake valve dead time falls within a predetermined range of the intake valve closing timing. The profile of the variable member is formed so as to shift to the valve stop state when the timing is on the retard side of the point. For this reason, in the internal combustion engine that performs the slow closing Atkinson cycle operation, the closing timing of the intake valve is shifted to the valve stop state while preventing the timing near the intake bottom dead center where the occurrence of knocking is high. Thereby, it becomes possible to promptly shift to the valve stop state while reducing the concern about the occurrence of knocking.

According to the third aspect of the invention, compared to the case where the lost motion portion is formed as a concave surface that is depressed from the virtual extension line of the slide surface, the valve is operated from the valve operating state in which the operating angle immediately before shifting to the valve stop state is obtained. It becomes possible to shift to the stop state more quickly.

According to the fourth or fifth aspect of the present invention, it is possible to smoothly perform the transition of the operation state of the intake valve between the valve operating state and the valve stop state. The occurrence of sudden changes and torque shocks can be satisfactorily reduced.

It is a figure for demonstrating the system configuration | structure of the internal combustion engine in Embodiment 1 of this invention. It is a figure which shows schematic structure of the intake variable valve operating apparatus shown in FIG. FIG. 3 is a view of the intake variable valve operating apparatus shown in FIG. 1 as viewed from the axial direction of the cam shaft (and the control shaft) (more specifically, the direction of arrow A in FIG. 2). FIG. 3 is a view of the intake variable valve operating apparatus shown in FIG. 1 as viewed from the axial direction of the cam shaft (and the control shaft) (more specifically, the direction of arrow A in FIG. 2). It is the perspective view which expanded the front-end | tip part of the rocking | fluctuating arm. It is a figure for demonstrating the valve lift characteristic used in Embodiment 1 of this invention in contrast with the valve lift characteristic used conventionally. It is the figure which compared and represented the relationship between valve lift amount and the rotation angle of a control shaft between this-application embodiment and a prior art. It is a figure for demonstrating schematic structure of the intake variable valve operating apparatus in Embodiment 2 of this invention. It is a figure for demonstrating the setting of the profile of the curve disk with which the intake variable valve operating apparatus shown in FIG. 8 is provided. It is a figure for demonstrating schematic structure of the intake variable valve operating apparatus in Embodiment 3 of this invention. It is a figure for demonstrating the structure of the cam type actuator which drives the control shaft shown in FIG. It is a figure for demonstrating the setting of the profile of the curve disk with which the intake variable valve operating apparatus shown in FIG. 10 is provided.

10, 100, 120 Internal combustion engine 16 Intake passage 18 Exhaust passage 24 Fuel injection valve 26 Spark plugs 28, 106, 126 Intake valve 30 Exhaust valve 32 Intake variable valve gear 36 Catalyst 40 ECU (Electronic Control Unit)
50, 104, 124

Cam shafts

52, 102, 122

Drive cams

54, 110, 130 Control shaft 56 Control

shaft drive mechanism

62, 140

Servo motors

70, 112, 132 Swing arm 72 Slide surface 74 First roller 76 Second roller 78 Support arm 80 Control arm 82 Swing cam surface

82a Non-operation surface

82b Operation surface

84, 108, 128 Rocker arm 86 Rocker roller 90 Virtual extension line 92

Lost motion part

114, 142 Curved disk 114a, 142a First curve

part

114b, 142b

Second curve portion

114c, 142c Third curve portion 134 Input portion 134a Cam roller 136 Oscillating cam 138 Cam type actuator

Embodiment 1 FIG.
[System configuration of internal combustion engine]
FIG. 1 is a diagram for explaining a system configuration of an internal combustion engine 10 according to Embodiment 1 of the present invention. The system of this embodiment includes an internal combustion engine 10. The internal combustion engine 10 is an internal combustion engine that performs an operation using an Atkinson cycle (hereinafter referred to as a “lately closed Atkinson cycle”) realized by delaying the closing timing of the intake valve 28 from the intake bottom dead center. Although the number of cylinders of the internal combustion engine in the present invention is not particularly limited, here, the internal combustion engine 10 is an inline 4-cylinder engine as an example.

In the cylinder of the internal combustion engine 10, a piston 12 is provided. A combustion chamber 14 is formed in the cylinder of the internal combustion engine 10 on the top side of the piston 12. An intake passage 16 and an exhaust passage 18 communicate with the combustion chamber 14.

Near the inlet of the intake passage 16, an air flow meter 20 that outputs a signal corresponding to the flow rate of air sucked into the intake passage 16 is provided. A throttle valve 22 is provided downstream of the air flow meter 20. A fuel injection valve 24 for injecting fuel into the intake port of the internal combustion engine 10 is disposed downstream of the throttle valve 22. An ignition plug 26 is attached to the cylinder head provided in the internal combustion engine 10 so as to protrude from the top of the combustion chamber 14 into the combustion chamber 14. The intake port and the exhaust port are respectively provided with an intake valve 28 and an exhaust valve 30 for bringing the combustion chamber 14 and the intake passage 16 or the combustion chamber 14 and the exhaust passage 18 into a conduction state or a cutoff state.

The intake valve 28 and the exhaust valve 30 are driven by an intake variable valve operating device 32 and an exhaust valve operating device 34, respectively. A detailed configuration of the intake variable valve operating device 32 will be described later with reference to FIGS. 2 to 5. A catalyst 36 for purifying the exhaust gas is disposed in the exhaust passage 18.

The system shown in FIG. 1 includes an ECU (Electronic Control Unit) 40. Various sensors for detecting the operation state of the internal combustion engine 10 such as the air flow meter 20 and the crank angle sensor 42 for detecting the engine speed are connected to the input of the ECU 40. Further, various actuators for controlling the operating state of the internal combustion engine 10 such as the throttle valve 22, the fuel injection valve 24, the spark plug 26, and the intake variable valve operating device 32 are connected to the output of the ECU 40. . The ECU 40 controls the operating state of the internal combustion engine 10 based on those sensor outputs.

[Configuration of variable valve gear]
FIG. 2 is a diagram showing a schematic configuration of the intake variable valve operating apparatus 32 shown in FIG. 3 and 4 respectively show the intake variable valve operating apparatus 32 shown in FIG. 1 from the axial direction of the cam shaft 50 (and the control shaft 54) (more specifically, from the direction of arrow A in FIG. 2). FIG. More specifically, FIG. 3 is a diagram when the operation state of the intake valve 28 is in a “valve operating state” to be described later, and FIG. 4 is a “valve stop state” in which the operation state of the intake valve 28 is described later. FIG. In FIG. 2, only the configuration relating to two of the four cylinders included in the internal combustion engine 10 is shown, and the remaining cylinders are not shown.

The intake variable valve operating apparatus 32 is simply abbreviated as “operating angle” when there is no need to distinguish between the operating angle and the lift amount of the intake valve 28 in accordance with the rotational position of the control shaft 54 to be described later. Is a device that can be continuously changed. Further, the intake variable valve operating device 32 is a valve that maintains the operation state of the intake valve 28 in the closed position (zero lift) by continuously changing (decreasing) the operating angle of the intake valve 28. It is configured so that it can be changed to a stopped state.

The intake variable valve operating apparatus 32 includes a drive cam 52 provided on a cam shaft 50 that is rotationally driven by a crankshaft 38 of the internal combustion engine 10, and a control shaft 54 that is disposed in parallel with the cam shaft 50. . The drive cam 52 rotates counterclockwise in FIG.

Further, as shown in FIG. 2, the intake variable valve operating device 32 has a control shaft drive mechanism 56 that can rotate the control shaft 54 within a predetermined angle range. The control shaft drive mechanism 56 includes a worm wheel 58 fixed to one end of the control shaft 54, a worm gear 60 that meshes with the worm wheel 58, and a servo motor 62 that rotationally drives the worm gear 60. The servo motor 62 is connected to the ECU 40 described above via an EDU (Electrical Driver Unit) 64. In addition to the crank angle sensor 42, the ECU 40 is connected with a cam angle sensor 66 that detects the rotation angle of the cam shaft 50 and a control shaft position sensor 68 that detects the rotation position (rotation angle) of the control shaft 54. Has been. According to such a configuration, the rotation position (rotation angle) of the control shaft 54 can be controlled by controlling the rotation direction and the rotation amount of the servo motor 62. Further, since the intake variable valve operating device 32 is a device that can continuously change the operating angle of the intake valve 28 in accordance with the rotational position of the control shaft 54, based on the output value of the control shaft position sensor 68, The operating angle and lift amount of the intake valve 28 can be acquired.

Furthermore, the intake variable valve operating device 32 has a swing arm (swing cam arm) 70. The swing arm 70 is installed to be swingable about the control shaft 54. A sliding surface 72 is formed on the swing arm 70 on the side facing the drive cam 52.

A first roller 74 and a second roller 76 are disposed between the swing arm 70 and the drive cam 52. The first roller 74 is in contact with the peripheral surface of the drive cam 52, and the second roller 76 is in contact with the slide surface 72 of the swing arm 70. These

rollers

74 and 76 are coaxially arranged and can be rotated independently of each other.

The

rollers

74 and 76 are supported by the tip of the support arm 78. A control arm 80 protruding downward in FIG. 3 is provided on the control shaft 54, and a base end portion of a support arm 78 is rotatably connected to a distal end portion of the control arm 80. Thereby, the

rollers

74 and 76 can be moved by rotating the control shaft 54. That is, when the control shaft 54 is rotated counterclockwise from the state shown in FIG. 4, the

rollers

74 and 76 are pulled by the control arm 80 and the support arm 78, and the swing center of the swing arm 70 (ie, the control shaft). 54 center). Further, when the control shaft 54 is rotated clockwise from a state where the

rollers

74 and 76 are close to the swing center, the

rollers

74 and 76 move away from the swing center.

FIG. 3 shows a state in which the positions of the

rollers

74 and 76 are closest to the swing center. The slide surface 72 has a curved surface (for example, a circular arc surface) in which the distance from the center of the drive cam 52 gradually decreases from the tip end side of the swing arm 70 toward the swing center side.

A swing cam surface 82 is formed on the swing arm 70 on the opposite side of the slide surface 72. The oscillating cam surface 82 is provided continuously from the non-operating surface (basic circle portion) 82a formed so that the distance from the oscillating center of the oscillating arm 70 is constant, and the non-operating surface 82a. The working surface 82b is formed so that the distance from the moving center gradually increases. Such a swing arm 70 is urged clockwise in FIG. 3 by a lost motion spring (not shown). By this urging force, the swing arm 70 is pressed against the second roller 76, and the first roller 74 is pressed against the drive cam 52.

The intake variable valve operating apparatus 32 further includes a rocker arm 84 that presses the valve shaft of the intake valve 28 in the lift direction. The rocker arm 84 is disposed below the swing arm 70 in FIG. The rocker arm 84 is provided with a rocker roller 86 so as to face the swing cam surface 82. The rocker roller 86 is rotatably attached to an intermediate portion of the rocker arm 84. One end of the rocker arm 84 is in contact with the valve shaft end of the intake valve 28, and the other end is supported by a hydraulic lash adjuster 88. The intake valve 28 is urged in a closing direction, that is, a direction in which the rocker arm 84 is pushed up by a valve spring (not shown). The rocker roller 86 is pressed against the swing cam surface 82 of the swing arm 70 by this urging force and the hydraulic lash adjuster 88. According to such a configuration, when the drive cam 52 rotates, the cam lift of the drive cam 52 is transmitted to the swing arm 70 via the

rollers

74 and 76, so that the swing arm 70 swings.

In the swing arm 70, a lost motion portion 92 is formed at the tip of the slide surface 72. The lost motion portion 92 is formed by a surface that is lower than the virtual extension line 90 of the slide surface 72. FIG. 5 is an enlarged perspective view of the tip portion of the swing arm 70. As shown in FIG. 5, the lost motion portion 92 is formed in a planar shape. In the state shown in FIG. 4, the second roller 76 is in contact with the lost motion portion 92. In this state, as will be described later, even if the swing arm 70 swings due to the rotation of the drive cam 52, the intake valve 28 is maintained in the valve closing position.

4, when the control shaft 54 is rotated counterclockwise from the valve stop state shown in FIG. 4, the

rollers

74 and 76 move in a direction approaching the swing center of the swing arm 70. As a result, the second roller 76 comes into contact with the slide surface 72. In this state, the intake valve 28 opens and closes as the swing cam 70 swings as the drive cam 52 rotates. This state is hereinafter referred to as “valve operating state”.

When the drive cam 52 is not lifted in the valve operating state, that is, when the basic circle portion of the drive cam 52 is in contact with the first roller 74, the rocker roller 86 is in contact with the non-operation surface 82a of the swing cam surface 82. In contact. Thereby, the intake valve 28 is closed. When the drive cam 52 begins to lift and the swing arm 70 begins to swing counterclockwise in FIG. 3, the contact point between the rocker roller 86 and the swing cam surface 82 (hereinafter referred to as “rocker roller contact point”). Is transferred from the non-working surface 82a to the working surface 82b. When the rocker roller contact point shifts to the action surface 82b, the rocker arm 84 is pushed down and the intake valve 28 is opened.

Suppose now that the

rollers

74 and 76 are at a position closest to the swing center of the swing arm 70. At this time, since the cam lift of the drive cam 52 is transmitted to the swing arm 70 at a position close to the swing center, the swing range (swing width) of the swing arm 70 is increased. For this reason, the operating angle of the intake valve 28 increases. Further, as described above, the closer to the swing center, the smaller the distance between the slide surface 72 and the center of the drive cam 52. Therefore, the position of the swing arm 70 at which the drive cam 52 starts to lift moves counterclockwise in FIG. 3 as the

rollers

74 and 76 approach the swing center. For this reason, after the swing arm 70 starts swinging, the amount of rotation of the swing arm 70 required until the rocker roller contact point moves to the action surface 82b (that is, until the intake valve 28 starts to lift). Becomes smaller as the

rollers

74 and 76 are closer to the swing center. This also increases the operating angle of the intake valve 28.

Conversely, if the

rollers

74 and 76 are at a position far from the swing center of the swing arm 70, the cam lift of the drive cam 52 is transmitted to the swing arm 70 at a position far from the swing center. For this reason, the swing range (swing width) of the swing arm 70 is reduced. In addition, after the swing arm 70 starts swinging, the amount of rotation of the swing arm 70 required until the rocker roller contact point shifts to the action surface 82b increases as the

rollers

74 and 76 become farther from the swing center. Become. For these reasons, the working angle of the intake valve 28 becomes smaller as the

rollers

74 and 76 are farther from the swing center.

As described above, in the intake variable valve operating apparatus 32, the operating angle of the intake valve 28 is continuously increased as the rotational position of the control shaft 54 is displaced more counterclockwise in FIG. Conversely, as the rotational position of the control shaft 54 is displaced more in the clockwise direction in FIG. 3, the operating angle of the intake valve 28 can be continuously reduced. Further, when the rotational position of the control shaft 54 is greatly displaced clockwise until the second roller 76 comes into contact with the lost motion portion 92, the drive cam 52 is rotated as shown in FIG. Accordingly, even if the swing arm 70 swings, the rocker roller contact point remains in the non-working surface 82a and does not reach the working surface 82b. Thereby, the operation state of the intake valve 28 can be shifted to the valve stop state.

FIG. 6 is a diagram for explaining the valve lift characteristics used in the first embodiment of the present invention in comparison with the conventionally used valve lift characteristics. More specifically, FIG. 6A shows the valve lift characteristics used in the present embodiment, and FIG. 6B shows the valve lift characteristics used conventionally.

First, the large operating angle θ1 shown in FIG. 6A is the action of the intake valve 28 used when performing an operation using the slow closing Atkinson cycle (hereinafter abbreviated as “late closing Atkinson cycle operation”). It is a horn. At the large operating angle θ1, the closing timing of the intake valve 28 is sufficiently retarded to such an extent that the return of intake air to the intake passage 16 occurs intentionally. Such a large operating angle θ <b> 1 is used in the partial load region of the internal combustion engine 10. More specifically, when the slow closing Atkinson cycle operation is performed in the partial load region, the closing timing of the intake valve 28 is a predetermined range with the large operating angle θ1 as the upper limit, depending on the required load and the required engine speed. It can be changed within.

Next, the large working angle θ2 shown in FIG. 6A is a working angle used at a high engine speed, and is set so that the internal combustion engine 10 can emit the maximum output. Since this large working angle θ2 is a value having the above-described character, it is smaller than the large working angle θ1 depending on the advance angle at the closing timing of the intake valve 28 so that a sufficient amount of air is filled in the cylinder. Is set to

Next, the medium operating angle θ3 shown in FIG. 6A is an operating angle used when low speed torque is requested (when torque is requested in the low speed region of the internal combustion engine 10). Here, as such an intermediate operating angle θ3, an example in which the closing timing of the intake valve 28 is retarded from the intake bottom dead center is illustrated. This intermediate operating angle θ3 is also a value that changes as the closing timing of the intake valve 28 is varied in accordance with the intake air temperature. More specifically, the closing timing of the intake valve 28 is retarded when there is a concern about the occurrence of knocking when the intake air temperature is high, and conversely when the intake air temperature is low. In order to increase the amount of air filled in the cylinder, it is advanced toward the intake bottom dead center. In this case, as an example, the variable range of the closing timing of the intake valve 28 is set to 180 to 200 ° CA (reference is exhaust top dead center) in terms of crank angle.

In the intake variable valve operating apparatus 32, the operating angle (and lift amount) of the intake valve 28 is continuously varied between the large operating angle θ1 and the intermediate operating angle θ3 (see FIG. 3). ). As described above, in the internal combustion engine 10 in which the working angle of the intake valve 28 is variable, as described above, when low-speed torque is required when the slow-closing Atkinson cycle operation using the large working angle θ1 is performed, the above-described operation is performed. The control shaft 54 is rotationally driven by the servo motor 62 so that the intermediate working angle θ3 is obtained. Then, after being controlled to the medium operating angle θ3, as the load of the internal combustion engine 10 and the engine speed increase, the operating angle of the intake valve 28 becomes the required torque due to the delay of the closing timing of the intake valve 28. It will be expanded to a value according to the size.

Further, as shown in FIG. 6A, when the control shaft 54 is rotationally driven to a position past the valve operating state where the intermediate operating angle θ3 when the low speed torque is requested is obtained, the operating state of the intake valve 28 The profile of the swing arm 70 (the slide surface 72 and the lost motion portion 92) is formed so that the valve suddenly shifts to the valve stop state. With this setting of the swing arm 70 profile, in the present embodiment, when the closing timing of the intake valve 28 is within a predetermined range near the intake bottom dead center, the operating state of the intake valve 28 shifts to the valve stop state. It is set to be. More specifically, the profile of the swing arm 70 indicates that when the closing timing of the intake valve 28 is a timing retarded from the intake bottom dead center within the predetermined range, the operating state of the intake valve 28 is stopped. It is formed to shift to a state.

On the other hand, the conventional valve lift characteristic shown in FIG. 6B referred to for comparison with the valve lift characteristic shown in FIG. 6A is realized by accelerating the closing timing of the intake valve with respect to the intake bottom dead center. The present invention is applied to an internal combustion engine that performs an early closing Atkinson cycle operation using an Atkinson cycle (hereinafter referred to as an “early closing Atkinson cycle”). The small operating angle θ4 in FIG. 6B is the minimum operating angle of the intake valve 28 used when the fast closing Atkinson cycle operation is performed. Note that the large working angle θ2 and the medium working angle θ3 in FIG. 6B are the same as those described above.

A variable valve operating apparatus capable of realizing the conventional valve lift characteristics shown in FIG. 6B is disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-121458. In the variable valve operating apparatus, as shown in FIG. 6B, when the control shaft is rotationally driven to a position past a valve operating state where a small operating angle θ4 is obtained, the operating state of the intake valve suddenly changes. The profile of the swing arm is formed so as to shift to the valve stop state. According to such a conventional configuration, only the amount indicated as “difference from the embodiment of the present application” in FIG. 6B (that is, only the difference between the medium operating angle θ3 and the small operating angle θ4), The valve is shifted to the valve stop state on the advance side with respect to the timing of the shift to the valve stop state in the present embodiment.

FIG. 7 is a diagram showing the relationship between the valve lift amount and the rotation angle of the control shaft in comparison between the embodiment of the present invention and the conventional technology.
The intake variable valve operating device 32 performs control so that the operation state of the intake valve 28 shifts to the valve stop state when a fuel cut execution request for the internal combustion engine 10 is issued. In particular, the engine speed is often high under conditions where fuel cut is required during deceleration. As a result, a valve stop request accompanying a fuel cut execution request is often issued when the operating angle of the intake valve 28 is controlled near the large operating angle θ2, as shown in FIG.

When the transition from the valve operating state controlled to the large operating angle θ2 as described above to the valve stopped state is performed, the configuration of the present embodiment in which the valve suddenly shifts to the valve stopped state at a position past the intermediate operating angle θ3. Accordingly, the rotation angle (operation amount) of the control shaft required to shift to the valve stop state is small as compared with the configuration of the prior art in which the change of the operation angle is required to a position beyond the small operation angle θ4. It will be over. Thereby, when performing the said transition, the operation time required for the transition to a valve stop state can be shortened. In order to suppress the deterioration of the catalyst 36 during the fuel cut, it is desired to shift to the valve stop state in as short a time as possible in order to quickly shut off the fresh air flow into the catalyst 36. According to the configuration of the present embodiment, it is possible to satisfactorily shorten the operation time required for the transition from the valve operating state controlled near the large operating angle θ2 that is actually performed when a fuel cut is requested to the valve stop state. Thus, it is possible to quickly realize a state in which fresh air does not flow into the catalyst 36 by stopping the valve. For this reason, it becomes possible to shift to the execution of the fuel cut while eliminating the concern about the suppression of the deterioration of the catalyst 36 at an earlier timing than when the fuel cut is requested.

Also, as the closing timing of the intake valve 28 approaches the intake bottom dead center, the actual compression ratio of the internal combustion engine 10 increases, so that knocking is likely to occur. According to the configuration of the conventional variable valve device described above, when shifting from the state controlled to the large operating angle θ2 to the valve stop state, the closing timing of the intake valve is in the vicinity of the intake bottom dead center where there is a high risk of occurrence of knocking. After passing the time, the position is controlled to a position past the small operating angle θ4. As a result, knocking is likely to occur during the transition to the valve stop state (in addition, even if the fuel cut is performed at an early stage during the transition to the valve stop state, it remains in the cylinder. Similarly, knocking is likely to occur due to the presence of fuel. In contrast, in the intake variable valve operating apparatus 32 of the present embodiment, as described above, when the closing timing of the intake valve 28 is at a timing retarded from the intake bottom dead center, the operating state of the intake valve 28 is changed. The profile of the swing arm 70 is formed so that the valve is stopped. As a result, in the internal combustion engine 10 that performs the slow-closing Atkinson cycle operation, the closing timing of the intake valve 28 is shifted to the valve stop state while preventing the timing near the intake bottom dead center from passing, so there is a concern about the occurrence of knocking. This makes it possible to promptly shift to the valve stop state.

Further, the lost motion portion 92 included in the profile of the swing arm 70 of the present embodiment is formed in a planar shape. Thereby, compared with the case where the lost motion part is formed of a concave surface that is depressed more than the virtual extension line of the slide surface, it is possible to make the transition from the valve operating state where the intermediate working angle θ3 is obtained to the valve stopped state earlier. . In addition, it is easier to manufacture the lost motion part 92 in a planar shape than in a concave shape. In addition, in terms of making the transition from the valve operating state to the valve stop state earlier, the configuration of the lost motion part is not limited to a planar shape, and curves in the direction opposite to the slide surface 72 from the tip of the slide surface 72 via an inflection point. You may be comprised by the convex surface to do.

Further, according to the intake variable valve operating apparatus 32, in the valve stop state, the

rollers

74 and 76 are located closer to the swing center of the swing arm 70 than the configuration of the conventional variable valve apparatus. The operations of the

rollers

74 and 76 and the swing arm 70 are performed (see FIG. 4). Thereby, the inertia weight of the swing arm 70 and the

rollers

74 and 76 can be reduced, and the mobility of the intake variable valve operating apparatus 32 is improved.

By the way, in the above-described first embodiment, when the closing timing of the intake valve 28 is a timing retarded from the intake bottom dead center, the intake valve 28 is oscillated so that the operating state of the intake valve 28 becomes the valve stop state. The configuration in which the profile of the arm 70 is formed has been described as an example. However, the profile of the variable member in the present invention is not necessarily limited to the above. That is, it may be a profile formed so that the operation state of the intake valve becomes a valve stop state when the intake valve close timing is within a predetermined range near the intake bottom dead center. For example, the intake valve close timing The profile of the variable member is formed so that the operating state of the intake valve becomes the valve stop state when the engine is at the intake bottom dead center within the predetermined range or at the advance side of the intake bottom dead center. It may be a configuration.

In the first embodiment described above, the second roller 76 corresponds to the “mating member” in the first invention, and the swing arm 70 corresponds to the “variable member” in the first invention. .
The swing arm 70 corresponds to the “swing member” in the third invention, and the second roller 76 and the first roller 74 correspond to the “intermediate member” in the third invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 8 is a diagram for explaining a schematic configuration of the intake variable valve operating apparatus 100 according to the second embodiment of the present invention.

The intake variable valve operating apparatus 100 shown in FIG. 8 mainly includes a cam shaft 104 to which a drive cam 102 is fixed and a transmission element (hereinafter referred to as a “rocker arm”) that presses the valve shaft of the intake valve 106 in the lift direction. ) 108, an adjusting device (hereinafter referred to as “control shaft”) 110 that functions as a control shaft in the present invention, and a drive cam 102, a rocker arm 108, and a control shaft 110. And a turning lever 112 (hereinafter referred to as a “swinging arm”). More specifically, the swing arm 112 is disposed so as to contact the profile of the curved disk 114 provided on the control shaft 110. Note that the basic configuration of the intake variable valve operating apparatus 100 is described in detail, for example, in Japanese Patent Publication No. 2004-521234.

FIG. 9 is a view for explaining the profile setting of the curved disk 114 provided in the intake variable valve operating apparatus 100 shown in FIG.
As shown in FIG. 9, the profile of the curved disk 114 indicates that the first curved portion 114a that contacts the swing arm 112 when the operating angle of the intake valve 106 is changed between the large operating angle θ1 and the intermediate operating angle θ3. A second curve portion 114b that contacts the swing arm 112 when the operation state of the intake valve 106 is a valve stop state, and a third curve that is interposed between the first curve portion 114a and the second curve portion 114b. Part 114c.

More specifically, the first curve portion 114a is formed such that the distance from the axis center of the control shaft 110 increases as the distance from the third curve portion 114c increases. The angle θ1 is configured to be obtained. The second curved portion 114b is a surface that is one step lower than the position where the intermediate working angle θ3 is realized in the first curved portion 114a, and is formed as an arc-shaped surface that does not change the distance from the center of the control shaft 110. Yes. And the 3rd curve part 114c is formed so that between such a 1st curve part 114a and the 2nd curve part 114b may be connected smoothly.

In the intake variable valve operating apparatus 100 having the above-described configuration, the operating angle and lift of the intake valve 106 are changed by changing the posture of the swing arm 112 by changing the rotational position of the curved disk 114 of the control shaft 110. The amount can be continuously changed, and the operation state of the intake valve 106 can be shifted to the valve stop state. More specifically, when the swing arm 112 is in contact with the first curved portion 114a (continuous variable section), the control shaft 110 (curved disc 114) is rotated counterclockwise in FIG. The operating angle of the intake valve 106 can be reduced. Then, the control shaft 110 (curved disc 114) is rotated until the portion of the curved disc 114 that contacts the swing arm 112 moves from the first curved portion 114a to the second curved portion 114b via the third curved portion 114c. As a result, the operating state of the intake valve 106 can be shifted to the valve stop state after passing through the speed sudden change section from the continuously variable section.

Also in the present embodiment, similarly to the above-described first embodiment, the valve is suddenly shifted to the valve stop state at a position past the intermediate operating angle θ3. As described above, the closing timing of the intake valve 106 is retarded from the intake bottom dead center. Even in the configuration of the intake variable valve operating apparatus 100 of the present embodiment described above, the same effects as those of the first embodiment described above, such as shortening of the operation time required for shifting to the valve stop state, can be achieved.

Furthermore, in the present embodiment, the third curved portion 114c of the curved disk 114 is formed so as to smoothly connect the first curved portion 114a and the second curved portion 114b. According to such a configuration, it is possible to smoothly shift the operation state of the intake valve 106 between the valve operating state and the valve stop state, and thereby, a sudden change in the operating state of the internal combustion engine 10 can be achieved. And the occurrence of torque shock can be reduced satisfactorily.

In the second embodiment described above, the swing arm 112 is the “mating member” in the first invention, and the curved disk 114 of the control shaft 110 is the “variable member” in the first invention. It corresponds.
The swing arm 112 corresponds to the “swing member” in the fourth invention, and the curved disk 114 corresponds to the “cam member” in the fourth invention.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS.
FIG. 10 is a diagram for explaining a schematic configuration of the intake variable valve operating apparatus 120 according to the third embodiment of the present invention.

The intake variable valve operating apparatus 120 shown in FIG. 10 is mainly driven in the axial direction, a cam shaft 124 to which the drive cam 122 is fixed, a rocker arm 128 that presses the valve shaft of the intake valve 126 in the lift direction. A control shaft 130 and a swing arm 132 that swings as the drive cam 122 rotates are provided. More specifically, the swing arm 132 includes an input unit 134 including a cam roller 134 a that contacts the drive cam 122, and a swing cam 136 that transmits the acting force of the drive cam 122 to the rocker arm 128. Then, by driving the control shaft 130 in the axial direction by a cam type actuator 138 to be described later, the mounting angle of the swing cam 136 with respect to the input unit 134 changes according to the axial position of the control shaft 130. ing. The basic configuration of the intake variable valve operating apparatus 120 is described in detail, for example, in Japanese Patent No. 3799944.

FIG. 11 is a diagram for explaining a configuration of a cam type actuator 138 that drives the control shaft 130 shown in FIG.
As shown in FIG. 11, the cam actuator 138 includes a servo motor 140 and a curved disk 142 provided on the output shaft 140 a of the servo motor 140. One end of the control shaft 130 described above is biased by a spring 144 so that contact with the profile of the curved disk 142 is always maintained. The spring 144 is disposed so as to be interposed between a stopper 130 a provided on the control shaft 130 and a bearing 146 of the control shaft 130. A reduction gear portion may be provided between the servo motor 140 and the curved disk 142.

FIG. 12 is a diagram for explaining the profile setting of the curved disk 142 provided in the intake variable valve operating apparatus 120 shown in FIG.
The profile of the curved disk 142 shown in FIG. 12 includes a first curved portion 142a, a second curved portion 142b, and a third curved portion 142c. The configuration of each of the curved portions 142a and the like is the same as the configuration of the profile of the curved disk 114 shown in FIG. 9, and therefore detailed description thereof is omitted here.

In the intake variable valve operating apparatus 120 having the above-described configuration, the operating angle of the intake valve 126 is changed by changing the axial position (stroke) of the control shaft 130 by rotationally driving the curved disk 142 by the servo motor 140. The lift amount can be continuously changed, and the operation state of the intake valve 126 can be shifted to the valve stop state. More specifically, in a state where the control shaft 130 is in contact with the first curved portion 142a (continuous variable section), the operating angle of the intake valve 126 is obtained by rotating the curved disc 142 clockwise in FIG. Can be reduced. The curve disk 142 is continuously variable by rotating the curve disk 142 until the portion of the curve disk 142 that contacts the control shaft 130 moves from the first curve portion 142a to the second curve portion 142b via the third curve portion 142c. The operating state of the intake valve 126 can be shifted to the valve stop state after passing through the speed sudden change section from the section.

Also in the present embodiment, similarly to the above-described first embodiment, the valve is suddenly shifted to the valve stop state at a position past the intermediate operating angle θ3. As described above, the closing timing of the intake valve 126 is retarded from the intake bottom dead center. Even in the configuration of the intake variable valve operating apparatus 120 of the present embodiment described above, the same effects as those of the first embodiment described above, such as shortening of the operation time required for shifting to the valve stop state, can be achieved.

Furthermore, in the present embodiment, the third curved portion 142c of the curved disc 142 is formed so as to smoothly connect the first curved portion 142a and the second curved portion 142b. According to such a configuration, it is possible to smoothly shift the operation state of the intake valve 126 between the valve operating state and the valve stop state, and thereby, the operating state of the internal combustion engine 10 is suddenly changed. And the occurrence of torque shock can be reduced satisfactorily.

In the third embodiment described above, the control shaft 130 corresponds to the “mating member” in the first invention, and the curved disk 142 corresponds to the “variable member” in the first invention.
Further, the swing arm 132 having the input part 134 and the swing cam 136 corresponds to the “swing member” in the fifth invention, and the curved disk 142 corresponds to the “cam member” in the fifth invention. Yes.

Claims

A variable valve operating device capable of changing the operation state of the intake valve to a valve stop state in which the intake valve is maintained in a closed state by continuously changing the lift amount and / or the operating angle of the intake valve,
A variable member having a profile that contacts a mating member included in the variable valve operating device;
The variable valve operating device changes a lift amount and / or a working angle of the intake valve by changing a contact position of the counterpart member on the profile of the variable member,
The profile of the variable member is formed so that the operation state of the intake valve shifts to the valve stop state when the closing timing of the intake valve is within a predetermined range near the intake bottom dead center. A variable valve operating apparatus for an internal combustion engine characterized by the above.
The internal combustion engine provided with the variable valve operating device is applied with an Atkinson cycle realized by delaying the closing timing of the intake valve from the intake bottom dead center,
The profile of the variable member indicates that the operation state of the intake valve shifts to the valve stop state when the intake valve is closed at a timing retarded from the intake bottom dead center within the predetermined range. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the variable valve operating apparatus is configured as described above.
The variable member is a swinging member that is disposed between a cam that drives the intake valve and the intake valve and swings as the cam rotates,
The counterpart member is an intermediate member that is disposed between the cam and the swing member and transmits the acting force of the cam to the swing member through the profile.
The profile of the swing member includes a slide surface that contacts the intermediate member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and the swing surface with respect to the slide surface. A lost motion portion that is provided at a distal end portion of the moving member far from the swing center, and that contacts the intermediate member when the operation state of the intake valve is the valve stop state,
The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the lost motion portion is formed in a planar shape.
The counterpart member is a swinging member that is disposed between a cam that drives the intake valve and the intake valve and swings as the cam rotates,
The variable member is a cam member that regulates the posture of the swing member with the cam,
The profile of the cam member includes a first curve portion that contacts the swing member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and an operating state of the intake valve. A second curved portion that contacts the rocking member when the valve is in a stopped state, and a third curved portion interposed between the first curved portion and the second curved portion,
The variable valve for an internal combustion engine according to claim 1 or 2, wherein the third curved portion is formed so as to smoothly connect the first curved portion and the second curved portion. apparatus.
The variable valve operating apparatus further includes a swinging member that is disposed between a cam that drives the intake valve and the intake valve, and that swings as the cam rotates.
The counterpart member is a control shaft that changes the posture of the swing member according to an axial position;
The variable member is a cam member that displaces the control shaft in the axial direction,
The profile of the cam member includes a first curve portion that contacts the swing member when the lift amount and / or operating angle of the intake valve is changed within a predetermined continuous variable section, and an operating state of the intake valve. A second curved portion that contacts the rocking member when the valve is in a stopped state, and a third curved portion interposed between the first curved portion and the second curved portion,
The variable valve for an internal combustion engine according to claim 1 or 2, wherein the third curved portion is formed so as to smoothly connect the first curved portion and the second curved portion. apparatus.