JP2001003721A - Variable valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly change each of the opening and closing periods of intake and exhaust valves. SOLUTION: This valve system is provided with a variable valve system in each of intake and exhaust valves 10 and (10'). Each variable valve system is provided with a control cam 15, which is eccentrically fixed to the outer periphery of a control shaft 14 extending in nearly parallel with a drive shaft 11 and a rocket arm 16 rotatably fitted externally to the outer periphery of this control cam 15 and transfers the rotation of the drive shaft 11 to rocking cams 18 for driving the intake and exhaust valves through this rocker arm 16. When the control cam 14 is rotated toward a small operating angle side, the lift peak period of an operating angle shifts toward a lag angle side in the intake valve side and toward and advancing angle side in the exhaust valve side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a variable valve actuation device which can change the operating angles and valve lifts of intake valves and exhaust valves (intake / exhaust valves) in accordance with the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art As is well known, to improve fuel efficiency at low engine speed and low load, to ensure stable driving performance, and to secure sufficient output by improving intake air filling efficiency at high speed and high load, etc. 2. Description of the Related Art Various variable valve operating devices capable of changing an operating angle and a valve lift of an exhaust valve according to an engine operating state have been conventionally proposed.

As an example, FIG. 11 shows a variable valve operating device described in Japanese Patent Application Laid-Open No. 55-137305. A drive shaft 2 that rotates in conjunction with the engine is provided above the cylinder head 1, and a drive cam 2 a is fixed to the outer periphery of the drive shaft 2. A swinging cam 8 for driving the suction / exhaust valve 6 is provided on a support shaft 9 extending substantially parallel to the drive shaft 2, and the cam surface 8 a of the swing cam 8 is connected to the suction / exhaust valve 6.
And comes into sliding contact with a valve lifter 7 provided at the upper end of the valve lifter. Reference numeral 10 denotes a spring that biases the swing cam 8 in one direction.

The driving cam 2a and the swing cam 8 are mechanically linked by a rocker arm 5. The rocker arm 5 is rotatably fitted on the outer periphery of the control cam 4 fixed eccentrically on the outer periphery of the control shaft 3. Then, by controlling the rotation of the control shaft 3, the center of the control cam 4, which is the rocking center of the rocker arm 5, is rotated with respect to the center of the control shaft 3, whereby the lift characteristic of the intake / exhaust valve 6 becomes continuous. It is constituted so that it may change.

[0005]

By the way, when the engine is idling or the like, the residual gas is utilized to reduce the pump loss to improve the fuel efficiency and to realize low-temperature combustion by the residual gas to purify the exhaust gas. Techniques for realizing this are well known in the art. In addition, at the time of large opening of the throttle, a large amount of residual gas is introduced into the combustion chamber, and in order to greatly reduce pump loss, the exhaust valve is closed before top dead center.
It is conventionally known that the compression work of the exhaust gas is effectively recovered by enclosing the exhaust gas in the cylinder and setting the opening timing of the intake valve after the top dead center.

As described above, in order to confine a large amount of residual gas into the combustion chamber, it is necessary to greatly advance the closing timing of the exhaust valve and significantly delay the opening timing of the intake valve. Also, in order not to increase the exhaust work too much, even if the opening timing of the exhaust valve is delayed, it is set to approximately near the bottom dead center, and
In order to prevent the intake work from increasing too much, the closing timing of the intake valve needs to be set to approximately near the bottom dead center even if it is advanced.

On the other hand, when the vehicle is fully opened, such as during rapid acceleration, the exhaust valve is closed at a time near the top dead center in order to reduce the exhaust work, and the intake valve is also almost opened at the top dead center to reduce the suction work. It is desirable to be near. In the low-speed range where the pulsation effect of the intake / exhaust system cannot be fully utilized, although there is a slight advance / delay due to gas inertia, both the opening timing of the exhaust valve and the closing timing of the intake valve are near the bottom dead center at the piston position. Is desirable.

As described above, in order to control the residual gas amount,
It is required to greatly change the closing timing of the exhaust valve and the opening timing of the intake valve. To control the expansion work and the charging efficiency, the variable width of the opening timing of the exhaust valve and the closing timing of the intake valve is reduced. Is required.

[0009] However, in the above-described conventional variable valve gear, no special consideration is given to the opening and closing timings of such intake and exhaust valves.

The present invention has been made in view of such problems, and has as its object to optimize the opening and closing timings of the intake and exhaust valves without providing a special drive / control mechanism. I have.

[0011]

According to the present invention, there is provided a variable valve operating apparatus for an internal combustion engine which mechanically includes a drive shaft which rotates in conjunction with rotation of the engine and a swing cam which drives an intake / exhaust valve. Are provided on the intake valve side and the exhaust valve side, respectively.

Each variable valve mechanism includes a control shaft extending substantially parallel to the drive shaft, a control cam eccentrically fixed to the outer periphery of the control shaft, and a rotatably fitted outer periphery of the control cam. A rocker arm linked at one end to the drive shaft side and linked to the swing cam side at the other end, with the center of the control cam, which is the swing center of the rocker arm, with the rotation of the control shaft. The valve rotates and moves with respect to the center of the control shaft, and the valve lift amount and the operating angle of the intake / exhaust valve continuously change.

According to the first aspect of the present invention, when the control shaft rotates to the small operation angle side, the lift peak timing of the operation angle moves to the retard side on the intake valve side and the advance angle on the exhaust valve side. It is set to move to the side.

According to a second aspect of the present invention, when the control shaft rotates to the small operating angle side, the rocking arm swing center is the same as the drive shaft rotation direction on the intake valve side with respect to the drive shaft center. In the direction of rotation of the drive shaft on the exhaust valve side.

According to the first and second aspects of the present invention, when the control shaft rotates to the small operation angle side, the valve lift amount and the operation angle decrease, and the lift peak timing of the operation angle is retarded on the intake valve side. To the advance side on the exhaust valve side. Therefore, the variable width of the opening timing on the intake valve side is larger than the variable width of the closing timing, and the variable width of the opening timing on the exhaust valve side is smaller than the variable width of the closing timing.

As a result, with the control shaft positioned on the small operating angle side, while maintaining the opening timing of the exhaust valve and the closing timing of the intake valve near the bottom dead center, The exhaust valve is closed before the top dead center, and the intake valve is opened after the top dead center, so that it is possible to improve fuel efficiency and purify exhaust using residual gas.

According to a third aspect of the present invention, when the control shaft rotates to a large operation angle side, the up operation angle becomes relatively large on the intake valve side and the down operation angle becomes relatively large on the exhaust valve side. It is characterized by having been set to.

According to the invention of claim 3, claim 1,
As in the invention, similarly to the invention, the variable width of the opening timing is larger on the intake valve side than the variable width of the closing timing, and the variable width of the opening timing is smaller on the exhaust valve side than the variable width of the closing timing. Therefore, the same functions and effects as those of the first and second aspects can be obtained.

Further, when the variable valve mechanism on the intake valve side and the variable valve mechanism on the exhaust valve side are arranged substantially plane-symmetrically with respect to the center of the engine, as in the fourth aspect of the invention, The same parts can be used for the exhaust valve, and the cost can be reduced. In this case, when the drive shafts of the intake and exhaust valves rotate in the same direction, the control axes of the intake and exhaust valves are set to rotate in opposite directions, and the drive shafts of the intake and exhaust valves are rotated in opposite directions. When rotating in the directions, the control shafts of the intake and exhaust valves are set to rotate in the same direction.

According to a fifth aspect of the present invention, in the locus of the rocker arm swing center, the first control position at which the operating angle becomes the largest is changed to the second control position corresponding to the partial load range, and the low-speed full-open range. Is set between the first control position and the third control position.

In this case, when the rocking center of the rocker arm moves to the control position corresponding to the low-speed full-open range, the lift peak timing of the operating angle moves to the advance side on the intake valve side and to the retard side on the exhaust valve side. It will be. That is, the lift peak timing of the operating angle can be shifted to both the retard side and the advance side according to the operating state of the engine, and the controllability thereof can be further improved.

Further, when the rotational phase of the control shaft from the state where the operating angle is the smallest to the state where the operating angle is the largest is set to be approximately 90 °, the operation is started. It is possible to maximize the shift amount at the angle lift peak time.

According to a seventh aspect of the present invention, there is provided an eccentric cam eccentrically fixed to the outer periphery of the drive shaft, and a ring-shaped ring rotatably fitted to the outer periphery of the eccentric cam. The tip is rotatably connected to one end of the rocker arm via a connection pin, and when the control shaft is located on the side of the large operating angle, the drive shaft is driven with respect to a line connecting the center of the drive shaft and the center of the connection pin. It is characterized in that the trajectory at the center of the connecting pin that moves in conjunction with the rotation of the shaft does not intersect.

More preferably, as in the invention of claim 8,
In a state where the control shaft is located on the side of the large operation angle, the trajectory of the center of the connection pin that swings in conjunction with the rotation of the drive shaft with respect to a line connecting the center of the drive shaft and the center of the connection pin is taken in. On the valve side, it is set on the rotation direction side of the drive shaft, and on the exhaust valve side, it is set on the side opposite to the rotation direction of the drive shaft.

[0025]

According to the present invention, each of the opening and closing timings of the intake and exhaust valves can be appropriately changed according to the operating state of the engine as the control shaft rotates. That is,
With a simple structure without using a special drive / control mechanism, it is possible to make the variable widths of the opening and closing timings of the intake and exhaust valves different from each other.

For example, by setting the variable width of the opening timing on the intake valve side larger than the variable width of the closing timing, and setting the variable width of the opening timing on the exhaust valve side smaller than the variable width of the closing timing,
While maintaining the opening timing of the exhaust valve and the closing timing of the intake valve in the vicinity of the bottom dead center, the exhaust valve is provided before the top dead center in a state where the control shaft is located on the small operating angle side as in the invention of claim 9. Is opened, and the intake valve is opened after the top dead center, so that the fuel efficiency can be improved and the exhaust gas can be purified using the residual gas.

[0027]

FIG. 5 shows a variable valve apparatus for an internal combustion engine according to a first embodiment of the present invention.

A drive shaft 11 on the intake valve side is provided above the intake valve 10, and a drive shaft 11 'on the exhaust valve side is provided above the exhaust valve 10'. Each drive shaft 11, 11 '
Extends in the cylinder row direction over all cylinders, has a sprocket attached to one end (not shown), and rotates in conjunction with a crankshaft of the engine via a timing chain or the like. An intake / exhaust valve 1 is provided on the outer periphery of each drive shaft 11, 11 '.
Oscillating cams 18 and 18 'for driving 0 and 10' are externally fitted so as to be relatively rotatable. Each swing cam 18, 18 '
Are formed on the outer periphery of the valve lifters 10a and 10a 'as transmission members provided at the upper ends of the intake and exhaust valves 10 and 10'.

A variable valve mechanism on the intake valve side for mechanically linking the drive shaft 11 on the intake valve side and the swing cam 18;
A variable valve mechanism on the exhaust valve side that mechanically links the drive shaft 11 ′ on the exhaust valve side and the swing cam 18 ′ is provided.

Here, the configuration on the intake valve side will be mainly described, and the configuration on the exhaust valve side will be denoted by adding a suffix (') to the corresponding configuration on the intake valve side, and redundant description will be omitted as appropriate. I do.

A ring-shaped eccentric cam 12 is fixed to the outer periphery of the drive shaft 11 by press fitting or the like. This eccentric cam 12
(Axis) C2 is the center (axis) C1 of the drive shaft 11.
Is eccentric by a predetermined amount. The base of a ring-shaped link 13 is fitted around the outer periphery of the eccentric cam 12 via a bearing or the like so as to be relatively rotatable.

A control shaft 14 is provided obliquely above the drive shaft 11 so as to extend in the cylinder row direction substantially parallel to the drive shaft 11. The control shaft 14 is rotated and held in a predetermined rotation range by an actuator or the like according to the operation state of the engine.

A ring-shaped control cam 15 is fixed to the outer periphery of the control shaft 14 by press fitting or the like. Control cam 1
5 is the center (axis) C4 of the control shaft 14.
3 is eccentric by a predetermined amount. A cylindrical central base of the rocker arm 16 is fitted around the outer periphery of the control cam 15 so as to be relatively rotatable. One end of the rocker arm 16 is connected to the distal end of the ring-shaped link 13 and the first connecting pin 19a.
Are rotatably connected via a.

The other end of the rocker arm 16 and the swing cam 18 are linked via a rod-like link 17. That is, the other end of the rocker arm 16 and the one end of the rod-shaped link 17 are rotatably connected via the second connection pin 19b, and the other end of the rod-shaped link 17 and the swing cam 18 are connected to the third end. It is rotatably connected via a connecting pin 19c.

With this configuration, when the drive shaft 11 rotates in conjunction with the rotation of the engine, the ring-shaped link 13 translates via the eccentric cam 12, and the rocker arm 16 moves the center of the control cam 15 accordingly. The swing cam 18 swings around C4 as a swing center, and swings via a rod-like link 17.
Swings. At this time, the cam surface of the swing cam 18 slides on the upper surface of a valve lifter 10a as a transmission member provided at the upper end of the intake valve 10, and presses the valve lifter 10a against the reaction force of a valve spring (not shown). By doing
The intake valve 10 opens and closes in conjunction with the rotation of the engine.

The control shaft 14 is controlled according to the operating state of the engine.
, The swing center C4 of the rocker arm 16 (the center of the control cam 15) rotates with respect to the center C3 of the control shaft 14, and the lift characteristic of the intake valve 10 changes continuously. Specifically, as the distance between the swing center C4 of the rocker arm 16 and the center C1 of the drive shaft 11 decreases, both the valve lift and the operating angle increase, and the distance between the centers C4 and C1 increases. Accordingly, both the valve lift and the operating angle become smaller.

As described above, since the swing cam 18 for driving the intake valve 10 is configured to be relatively rotatably fitted to the outer periphery of the drive shaft 11 that rotates in conjunction with the engine, the swing cam 18
There is no danger of the shaft center misalignment with respect to the drive shaft 11
Control accuracy is improved. Further, since it is not necessary to provide a support shaft for supporting the swing cam 18 separately from the drive shaft 11, it is possible to reduce the number of components and the arrangement space. Furthermore,
Since the connecting portions of the members are in surface contact, they have excellent wear resistance and are easy to lubricate.

Next, the characteristic structure and operation of this embodiment will be described in detail with reference to FIGS. 1 and 2 correspond to the view of the mechanism of FIG. 5 viewed from the opposite direction. The solid line in FIG. 1 indicates a state in which the swing center C4 of the rocker arm 16 is held at the large operating angle position P1 and the swing cam 18 swings in the valve opening direction, that is, the lift peak timing Q1 in FIG. The state of is shown.
On the other hand, the phantom line in FIG. 1 is the swing center C of the rocker arm 16.
4 is held at the small operation angle position P2 and the swing cam 18
Shows the state of swinging most in the valve opening direction, that is, the state of the lift peak timing Q2 in FIG.

With the rotation of the control shaft 14, the center C4 of the control cam 15, which is the rocking center of the rocker arm 16, becomes
The control shaft 14 moves on a locus K1 about the axis C3. In this locus K1, a large operating angle position P1 where the operating angle (and valve lift amount) of the intake valve 10 is the largest is located at (near) the portion closest to the center C1 of the drive shaft 11.
Is set.

From the large operating angle position P1 to the small operating angle position P
2, the control shaft 14 is set to rotate in the direction ω2 (clockwise in FIG. 1) opposite to the rotation direction ω1 of the drive shaft 11 in this embodiment. That is, when the control shaft 14 rotates to the small operation angle side (ω2), the swing center C4 of the rocker arm 16 is in the same direction (counterclockwise direction) as the rotation direction ω1 of the drive shaft 11 with respect to the center C1 of the drive shaft 11. ), That is, move to the retard side. As a result, the center C5 of the first connecting pin 19a that rotatably connects one end of the rocker arm 16 and the distal end of the ring-shaped link 13 is viewed from the center C1 of the drive shaft 11 in the rotational direction ω1 of the drive shaft 11.
Move to the side. As shown in FIG. 3, the lift peak timing of the operating angle moves to the retard side by the amount of the eccentricity (angle) α of the first connecting pin 19a (Q1 → Q2).

As described above, when the control shaft 14 rotates to the small operation angle side, the operation angle and the valve lift of the intake valve 10 gradually decrease, and the lift peak timing of the operation angle moves to the retard side. I do. As a result, the variable width of the opening timing of the intake valve 10 becomes relatively larger than the variable width of the closing timing.

Then, in the state of the small operating angle position P2, the opening timing of the intake valve 10 is greatly delayed while maintaining the closing timing of the intake valve 10 near the intake bottom dead center, so that it is later than the top dead center. It is set to become.

In this embodiment, in order to maximize the movement amount α of the operating angle during the lift peak period, the small operating angle position P2 where the operating angle is minimized is set to the rocker arm 16.
Of the drive shaft 11 in the locus K1 of the swing center C4 of
1 with respect to the rotational direction ω1 side (retard side) of the drive shaft 11
And position. That is, the line L1 connecting the small operation angle position P2 and the center C1 of the drive shaft 11 is set to be a tangent on the retard side from the swing center C4 to the locus K1. In this case, the state of the large operation angle position P1 is changed to the small operation angle position P2.
The rotation phase of the control shaft 14 up to the state described above is about 90 °.

Further, the control position P3 of the rocking center C4 of the rocker arm 16 corresponding to the low-speed full-open range is changed to the large operating angle position P.
1 is set on the opposite side of the small operating angle position P2 with respect to 1.
That is, in the locus K1 of the rocking center C4 of the rocker arm 16, the large operating angle position (first control position) P1 where the operating angle is the largest is changed to the small operating angle position P corresponding to the partial load range.
2 (second control position) and a control position (third control position) P3 corresponding to the low-speed full-open range.

As a result, when shifting from the large operating angle position P1 to the control position P3 corresponding to the low-speed full-open range, the valve lift and the operating angle are reduced, and the operating angle (the lift peak timing) of the intake valve is advanced. Move to the corner. As a result, the opening timing of the intake valve 10 can be appropriately advanced.

As described above, the lift peak timing of the operating angle of the intake valve 10 can be shifted to both the retard side and the advance side according to the operating state of the engine, so that a wider range of control is possible. .

FIG. 2 shows the attitude of the lift peak timing Q1 in the state of the large operating angle position P1, as in the solid line of FIG. In such a state, the drive shaft 1 is moved relative to a line L2 connecting the center C1 of the drive shaft 11 and the center C5 of the first connecting pin 19a.
The locus K2 of the center C5 of the first connecting pin 19a which moves in conjunction with the rotation of the first link 19, particularly the locus K3 corresponding to the lift range
Are set on the rotation direction ω1 side of the drive shaft 11. That is, the trajectory K3 is set so as not to intersect the line L2.

As a result, in the state of being held at the large operating angle position P1, the upward operating angle (from the opening timing to the lift peak timing) is decreased to the downward operating angle (from the lift peak timing to the closing timing).
It becomes relatively smaller by the angle α. Further, as the swing center C4 of the rocker arm 16 moves to the small operation angle side, the lift variable range becomes smaller, so that the ratio between the upward operation angle and the downward operation angle approaches 1: 1. As a result, the variable width of the opening timing of the intake valve 10 is smaller than the variable width of the closing timing.

Next, the structure and operation of the exhaust valve 10 'will be described with reference to FIGS.

On the exhaust valve side, the characteristics are set so as to be opposite to those on the intake valve side. That is, as in the embodiment shown in FIG. 5, the respective parts on the exhaust valve 10 'side are arranged substantially plane-symmetrically with respect to the respective parts on the intake valve 10 side with respect to the center of the engine, and
When the drive shafts 11, 11 'of the intake / exhaust valves 10, 10' are set to rotate in the same direction, the rotational direction ω2 of the control shaft 14 on the intake valve side and the control shaft 1 on the exhaust valve side.
The rotation direction ω2 ′ of 4 ′ is set in the opposite direction.
As a result, on the exhaust valve side, when the swing center C4 'of the rocker arm 16' rotates to the small operating angle side, the exhaust valve 1
The lift peak timing of the operation angle of 0 ′ moves to the advance side (Q1 ′ → Q2 ′).

In the state of the lift peak timing Q1 'at the large operating angle position P1', the center C1 'of the drive shaft 11'
A trajectory corresponding to the lift range at the center of the first connection pin 19a 'is located on the side opposite to the rotation direction ω1' of the drive shaft 11 'with respect to a line connecting the first connection pin 19a' and the center C5 'of the first connection pin 19a'. It is set as follows.

As a result, as shown in FIG.
The variable width of the closing timing of 0 ′ is relatively larger than the variable width of the opening timing. Therefore, with the shift to the small operating angle side,
While keeping the opening timing of the exhaust valve 10 'close to the bottom dead center, the closing timing can be made much earlier and set earlier than the top dead center.

As described above, in this embodiment, the control shafts 14, 1
The opening and closing timings of the intake and exhaust valves 10, 10 'can be appropriately changed according to the engine operating state in conjunction with the rotation operation of the 4', and a special drive / control mechanism is added. No need.

In particular, as shown in FIGS.
While maintaining the opening timing of 0 'and the closing timing of the intake valve 10 near the bottom dead center, the closing timing of the exhaust valve 10' is made earlier than the top dead center in the small operating angle position P2, and the intake valve is closed. By making the closing timing of the fuel cell 10 later than the top dead center, it is possible to improve fuel efficiency and purify exhaust gas by using residual gas.

In addition, when a variable valve mechanism having the same structure is applied to the intake valve side and the exhaust valve side as in this embodiment, the same parts can be used for the intake valve side and the exhaust valve side. In addition, cost can be reduced.

FIGS. 6 to 10 show second to sixth embodiments of the present invention.

The second embodiment shown in FIG. 6 is similar to the first embodiment shown in FIG.
Compared to the embodiment, the rotational directions ω1,
ω1 ′ and the rotational directions ω2, ω2 ′ of the control shafts 14, 14 ′.
Are set in the opposite directions.

In the third embodiment shown in FIG. 7, the components on the intake valve 10 side and the components on the exhaust valve 10 'side are arranged in the same manner when viewed in the axial direction. Further, the control shafts 14 and 14 'are rotated in the same direction as the rotation directions ω1 and ω1' of the drive shafts 11 and 11 '.
Are set in opposite directions to each other.

In the fourth to sixth embodiments shown in FIGS. 8 to 10, the rotation directions ω1 and ω1 ′ of the drive shafts 11 and 11 ′ are set to be opposite to each other, and the rotation directions ω2 and ω
2 ′ is set in the same direction. The arrangement of each part in FIGS. 8, 9 and 10 is the same as that in FIGS.

In the second to sixth embodiments, the same operation and effect as those of the first embodiment can be obtained.

The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, the variable valve mechanism having the same structure is used on the intake valve side and the exhaust valve side, but one variable valve mechanism may have a different structure.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a variable valve mechanism on the intake valve side of a variable valve apparatus according to the present invention.

FIG. 2 is an explanatory view showing a variable valve mechanism on the intake valve side.

FIG. 3 is a characteristic diagram showing a lift characteristic of an intake valve.

FIG. 4 is a characteristic diagram showing a lift characteristic of an exhaust valve.

FIG. 5 is a configuration diagram showing a variable valve train of the internal combustion engine according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram showing a variable valve operating device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram showing a variable valve apparatus for an internal combustion engine according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram showing a variable valve operating device for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram illustrating a variable valve apparatus for an internal combustion engine according to a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram showing a variable valve apparatus for an internal combustion engine according to a sixth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a variable valve device for an internal combustion engine according to a conventional example.

[Explanation of symbols]

 10, 10 '... intake / exhaust valve 11, 11' ... drive shaft 13, 11 '... ring-shaped link 14, 14' ... control shaft 15, 15 '... control cam 16, 16' ... rocker arm 17, 17 '... rod Link 18,18 '... Swing cam

Claims (9)

[Claims] A variable valve mechanism that mechanically links a drive shaft that rotates in conjunction with rotation of an engine and a swing cam that drives an intake / exhaust valve is provided on each of an intake valve side and an exhaust valve side. Each variable valve mechanism is provided, a control shaft extending substantially parallel to the drive shaft, a control cam eccentrically fixed to the outer periphery of the control shaft, and rotatably externally fitted to the outer periphery of the control cam, A rocker arm linked at one end to the drive shaft side and linked to the swing cam side at the other end, with the center of the control cam, which is the rocking center of the rocker arm, as the control shaft rotates. A variable valve train for an internal combustion engine that rotates with respect to the center of a control shaft and continuously changes a valve lift amount and an operation angle of an intake / exhaust valve, wherein when the control shaft rotates to a small operation angle side, When the lift peak timing of the operating angle moves to the retard side on the intake valve side, In both cases, the variable valve train of the internal combustion engine is set so as to move to the advance side on the exhaust valve side. 2. A variable valve mechanism that mechanically links a drive shaft that rotates in conjunction with rotation of an engine and a swing cam that drives an intake / exhaust valve is provided on each of an intake valve side and an exhaust valve side. Each variable valve mechanism is provided, a control shaft extending substantially parallel to the drive shaft, a control cam eccentrically fixed to the outer periphery of the control shaft, and rotatably externally fitted to the outer periphery of the control cam, A rocker arm linked at one end to the drive shaft side and linked to the swing cam side at the other end, with the center of the control cam, which is the rocking center of the rocker arm, as the control shaft rotates. A variable valve train for an internal combustion engine that rotates with respect to the center of a control shaft and continuously changes a valve lift amount and an operation angle of an intake / exhaust valve, wherein when the control shaft rotates to a small operation angle side, , The rocker arm swing center is on the intake valve side with respect to the center of the drive shaft. The variable valve operating device of the internal combustion engine, wherein the variable valve device is configured to move in the same direction as the rotation direction of the drive shaft, and to move in the direction opposite to the rotation direction of the drive shaft on the exhaust valve side. 3. A variable valve mechanism that mechanically links a drive shaft that rotates in conjunction with rotation of the engine and a swing cam that drives an intake / exhaust valve is provided on each of an intake valve side and an exhaust valve side. Each variable valve mechanism is provided, a control shaft extending substantially parallel to the drive shaft, a control cam eccentrically fixed to the outer periphery of the control shaft, and rotatably externally fitted to the outer periphery of the control cam, A rocker arm linked at one end to the drive shaft side and linked to the swing cam side at the other end, with the center of the control cam, which is the rocking center of the rocker arm, as the control shaft rotates. A variable valve train for an internal combustion engine that rotates with respect to the center of a control shaft and continuously changes a valve lift amount and an operating angle of an intake / exhaust valve, wherein the control shaft rotates to a large operating angle side. , The upward operating angle becomes relatively large on the intake valve side, A variable valve operating device for an internal combustion engine, wherein the operating angle is set to be relatively large. 4. A variable valve mechanism on the intake valve side and a variable valve mechanism on the exhaust valve side are disposed substantially symmetrically with respect to the center of the engine, and drive shafts of the intake and exhaust valves are in the same direction. When rotating, set the control shafts of the intake and exhaust valves to rotate in opposite directions.When the drive shafts of the intake and exhaust valves rotate in the opposite directions, control the intake and exhaust valves. The variable valve train of an internal combustion engine according to any one of claims 1 to 3, wherein the variable valve trains are set to rotate in the same direction. 5. A first control position at which the operating angle is the largest in the locus of the rocking center of the rocker arm is a second control position corresponding to a partial load range and a third control position corresponding to a low-speed fully open range. The variable valve train for an internal combustion engine according to any one of claims 1 to 4, wherein the variable valve train is set between the control position and the control position. 6. The rotation phase of the control shaft from the state where the operating angle is the smallest to the state where the operating angle is the largest is approximately 90.
The angle is set so as to be equal to °.
The variable valve train for an internal combustion engine according to any one of the above. 7. An eccentric cam eccentrically fixed to the outer periphery of the drive shaft, and a ring-shaped ring rotatably fitted to the outer periphery of the eccentric cam, and a tip of the ring-shaped link is a rocker arm. One end is rotatably connected via a connecting pin, and in a state where the control shaft is located on the side of the large operating angle, the rotation of the drive shaft with respect to a line connecting the center of the drive shaft and the center of the connecting pin. The variable valve train of an internal combustion engine according to any one of claims 1 to 6, wherein the trajectories of the centers of the connecting pins that move together are set so as not to intersect. 8. A line connecting the center of the drive shaft and the center of the connecting pin when the control shaft is located on the large operating angle side.
The trajectory of the center of the connecting pin that swings in conjunction with the rotation of the drive shaft is set on the rotation side of the drive shaft on the intake valve side, and opposite to the rotation direction of the drive shaft on the exhaust valve side. The variable valve train for an internal combustion engine according to claim 7, wherein 9. A method wherein the exhaust valve is closed before top dead center and the intake valve is opened after top dead center in a state where the control shaft is located on the small operation angle side. The variable valve train for an internal combustion engine according to any one of claims 1 to 8.