JP3094762B2 - Variable valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve apparatus for variably controlling the opening / closing timing and operating angle of an intake valve and an exhaust valve according to the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Various types of variable valve operating devices for internal combustion engines for variably controlling the opening / closing timing and operating angle of intake valves and exhaust valves have been conventionally provided. There is one described in Japanese Patent Publication No. 5-43847. The variable valve gear disclosed in this publication includes an opening / closing operation characteristic changing mechanism for selectively switching between a high-speed cam having a large operating angle and a lift amount and a low-speed cam having a small operating angle and a lift amount, and a phase angle between the crankshaft and the cam. , And two variable valve operating mechanisms.

[0003] Here, there are demands for an internal combustion engine to improve fuel efficiency in a low-load region and to improve output in a high-load region. Is known to be adjusted as follows.

First, in a low load region, fuel consumption can be improved by delaying the opening timing of the intake valve to eliminate valve overlap with the exhaust valve and reducing the amount of exhaust gas (combustion gas) remaining in the combustion chamber. . Further, by delaying the closing timing of the intake valve until the middle of the compression stroke, pumping loss can be reduced and fuel efficiency can be improved.

[0005] Next, in the low-rotation, high-load region, the opening timing of the intake valve is advanced to secure an appropriate overlap, and the output can be improved by increasing the exhaust efficiency. In addition, by advancing the closing timing of the intake valve, the charging efficiency at low rotation is increased, and the output can be improved.

Further, in the high rotation and high load range, the output can be improved by increasing the overlap by increasing the opening timing of the intake valve and increasing the exhaust efficiency. Also,
By delaying the closing timing of the intake valve, the filling efficiency at high rotation is increased, and the output can be improved.

[0007] In order to obtain the optimal opening / closing timing of the intake valve in each of the above-mentioned operating regions by the conventional apparatus described in the above-mentioned publication, the valve timing is switched according to the operating conditions as shown in FIG. I just need.

That is, when the engine is in the low load range, the high-speed cam having a large operating angle is selected by the opening / closing operation characteristic changing mechanism, and the entire opening / closing timing is delayed by the phase adjusting mechanism, so that the valve timing I indicated by the solid line is obtained.
Set to ₁ . As a result, the valve overlap is reduced by delaying the opening timing, while the pumping loss is reduced by delaying the closing timing.

When the engine is in the low-rotation, high-load range, a low-speed cam having a small operating angle is selected by the opening / closing operation characteristic changing mechanism, and the entire opening / closing timing is advanced by the phase adjusting mechanism, so that it is indicated by a dashed line. to set the valve timing I _2. Thereby, while the opening timing is advanced and an appropriate valve overlap can be obtained, the closing timing is advanced and the filling efficiency is increased.

Further, when the engine is in a high rotation and high load range,
By opening and closing characteristic changing mechanism with selecting large fast cam operating angle, by advancing the entire opening and closing timing by the phase adjusting mechanism may be set to the valve timing I ₃ shown by a dotted line. As a result, the opening timing is greatly advanced and the overlap is increased, while the closing timing is delayed and the charging efficiency is improved.

[0011]

However, in the above-described conventional apparatus, although the opening / closing operation characteristic changing mechanism and the phase adjusting mechanism are used, the valve timing of the intake valve can be appropriately switched according to the operating conditions. It is difficult to respond quickly to changes in actual operating conditions,
The drivability may be reduced.

That is, the normal operating state is, for example, a case where the operating condition shifts from a low load region to a low rotation high load region or from a low load region to a high rotation high load region, such as when the accelerator is depressed from a steady operation state. There are many.

Here, as shown in FIG. 14, when shifting from the low load region to the high rotation and high load region, only the phase adjustment mechanism is operated to advance the opening / closing timing of the intake valve. it can be switched from the valve timing I ₁ to the valve timing I ₃ at high speed and high load.

However, when the operating condition shifts from the low-load region to the low-rotation, high-load region, the operating angle is reduced by the opening / closing operation characteristic changing mechanism. can not be switched from the valve timing I ₁ when the load on the valve timing I ₂ at the time of low rotation and high load.

[0015] That is, in this case, because it requires the operation of both mechanisms, transferred to the valve timing initially actuates the phase control mechanism in I _3, the valve timing by then operating the opening and closing characteristic changing mechanism Reach I ₂ or
Or on the contrary, first to operate the opening and closing characteristic changing mechanism is transferred to the intermediate valve timing I ₄ indicated by the two-dot chain line in FIG. 14, then actuates the phase control mechanism in the valve timing I ₂ Have to reach or do.

Therefore, in the process of performing the two-stage adjustment, the valve timing of the intake valve necessarily deviates from the preferable timing, and during this time, there is a possibility that the operating performance is deteriorated.

Further, even if both mechanisms are operated simultaneously, it is practically difficult to make the operating speeds of both mechanisms coincide. Furthermore, even if simultaneous operation is realized, a predetermined operating oil pressure must be supplied to both mechanisms at the same time, so that it is necessary to increase the capacity of the oil pump, resulting in an increase in cost and the like.

[0018]

Accordingly, the present invention provides a first variable valve mechanism for providing a rotational phase difference between a drive shaft and a camshaft, and a first variable valve mechanism for changing a phase angle of the drive shaft with respect to a crankshaft. By using the variable valve mechanism of No. 2, valve timing according to the operating state of the engine is easily realized, and operability is improved. That is,
A variable valve apparatus for an internal combustion engine according to the present invention includes a drive shaft that rotates in synchronization with rotation of the engine, and a cam that is disposed coaxially with the drive shaft and that drives a suction and exhaust valve on an outer periphery. Shaft and the rotation of the drive shaft depending on the engine operating condition.
A first variable valve mechanism for changing the angular velocity of the camshaft, and a second variable valve mechanism for changing the phase angle of the drive shaft with respect to the crankshaft of the engine .
When the engine is in the low load range, the first variable valve
The operating angle of the intake valve is increased through the mechanism and
The opening and closing timing of the intake valve is delayed through the second variable valve mechanism.
The first control to be performed and when the engine is in a low rotation and high load region.
Sets the operating angle of the intake valve through the first variable valve mechanism.
The intake valve is smaller than the first control state.
The opening timing and closing timing of the motor are advanced from the state of the first control.
And controls the second variable valve mechanism with the first control.
Second control for maintaining the same state; and control means for performing the second control.
It is characterized by that. The first variable valve operating device
Is preferably provided at an end of the camshaft and has an engagement groove formed in a radial direction, and the flange is opposed to the one flange. The other flange portion provided on the drive shaft side and having an engagement groove formed in the radial direction, an annular disk slidably disposed between the two flange portions, and both sides of the annular disk Projecting in opposite directions to each other,
Pins respectively engaged in the respective engagement grooves of the both flange portions,
A drive mechanism for swinging the annular disk in accordance with an engine operating state .

Further, in the configuration of claim 2, the control means
However, when the engine is in a high rotation and high load region, the operating angle of the intake valve is increased through the first variable valve mechanism, and the opening and closing timing of the intake valve is increased through the second variable valve mechanism. The third control is performed to advance the value.

Further, in the configuration according to claim 3, in addition to the configuration according to claim 2, the control means is configured to control the engine when the engine is in an intermediate region between the low load region and the low rotation high load region. Performing a fourth control for setting the operating angle of the intake valve to an intermediate value between the operating angle in the low-load region and the operating angle in the low-rotation high-load region via the first variable valve mechanism; Features.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect, when the engine is in an intermediate region between the low load region and the high rotation and high load region, the control means controls the intake valve. The fifth control is performed to set the opening / closing timing of the second switching valve to an intermediate phase between the opening / closing timing in the low load range and the opening / closing timing in the high rotation / high load range via the second variable valve mechanism. .

Further, in the configuration of claim 5, in the configuration of claim 2, the control means is configured to control the intake air when the operating condition of the engine moves between the low load region and the low rotation high load region. The operating angle of the valve is configured to be changed substantially continuously between the operating angle in a low load region and the operating angle in a low rotation and high load region via the first variable valve mechanism. And

According to a sixth aspect of the present invention, in the second aspect of the present invention, the control means is configured to control the intake air when the operating condition of the engine moves between the low load region and the high rotation high load region. The opening and closing timing of the valve is changed substantially continuously between the opening and closing timing in a low load region and the opening and closing timing in a high rotation and high load region via the second variable valve mechanism. And

[0024]

The first variable valve mechanism operates according to the operating state of the engine.
Change the camshaft angular velocity with respect to the drive shaft rotation
Can be Particularly, in the control state in which the center of the annular disk of the first variable valve mechanism coincides with the center of the drive shaft, the camshaft synchronizes with the drive shaft at a constant speed, that is, the phase difference. The intake and exhaust valves open and close according to the profile of the cam. On the other hand, when the annular disk is swung to one side by the drive mechanism, the center of the annular disk is eccentric from the center of the drive shaft. As a result of the occurrence of a phase difference, the intake and exhaust valves open and close with characteristics such that the profile of the cam is retarded by the phase difference. On the other hand, the second variable valve mechanism can change the phase angle of the drive shaft with respect to the crankshaft of the engine.

Therefore, the first variable valve mechanism and the second
With the variable valve mechanism described above, the operating angle and the opening / closing timing can be appropriately adjusted, and various valve timings according to the operating state of the engine can be realized. In addition to this, by continuously changing the amount of eccentricity between the annular disk and the drive shaft and the amount of phase angle change between the crankshaft and the drive shaft, when changing from one valve timing to another valve timing. In addition, this timing can be continuously changed.

[0026] Then, it is possible to delay the closing timing while reducing the overlap by a first control to delay the time opening and closing as well as increasing the operating angle of the intake valve, the intake valve
Is smaller than the state of the first control.
In particular, the opening timing and closing timing of the intake valve are determined by the state of the first control.
You can hasten the closing timing than the first control while forming a moderate overlap by a second control Ru is advanced than. In particular, when the engine transitions between the low load region and the low rotation high load region, by operating only the first variable valve mechanism that can simultaneously adjust both the operating angle and the opening and closing timing, The valve timing suitable for the region can be obtained. Further, according to the configuration of the second aspect, the closing timing can be relatively delayed while a large overlap is formed by the third control that increases the operating angle of the intake valve and advances the opening / closing timing.

Furthermore, according to the configuration of claim 3, when the engine shifts between the low load region and the low rotation high load region,
Since the operating angle of the intake valve passes through an intermediate value, torque shock at the time of transition can be reduced.

According to the configuration of claim 4, when the engine shifts between the low load region and the high rotation high load region, the opening / closing timing of the intake valve passes through an intermediate phase. Torque shock can be reduced.

Further, according to the configuration of claim 5, when the engine transitions between the low load region and the low rotation high load region,
Since the operating angle of the intake valve is changed substantially continuously, torque shock at the time of shifting can be reduced.

According to the configuration of claim 6, when the engine shifts between the low load range and the high rotation high load range, the opening / closing timing of the intake valve is changed substantially continuously. Torque shock can be reduced.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described below with reference to FIGS.

FIG. 1 is an explanatory view showing the overall structure of the first embodiment. This variable valve operating apparatus includes a first variable valve operating mechanism 1 and a second variable valve operating mechanism which will be described later. The operating hydraulic pressure supplied to each of the variable valve mechanisms 1 and 43 is controlled by the controller 42.

First, the first variable valve mechanism 1 will be described with reference to an enlarged sectional view of FIG. 2. A hollow drive shaft 2 extending in the front-rear direction of the engine has a sprocket ( Rotational force is transmitted via each of them (not shown), and a camshaft 3 divided for each cylinder is disposed coaxially with the center X of the drive shaft 2 via a fixed gap on the outer periphery thereof. .

The camshaft 3 is rotatably supported by a cam bearing at the upper end of a cylinder head (not shown), and the intake valve 4 is disposed at a predetermined position on the outer periphery as shown in FIGS. A plurality of cams 7 that are opened by the valve lifter 6 against the spring force of the spring 5 are provided integrally.

Further, the camshaft 3 is divided into a plurality of pieces as described above, and a flange 8 is provided at one of the divided ends. A sleeve 9 and an annular disk 10 are disposed between the ends of the plurality of divided camshafts 3, respectively. As shown in FIG. 5, the flange portion 8 has an elongated rectangular engaging groove 11 formed in a radial direction from a hollow portion, and has a flange surface 8 a slidingly contacting one surface of the annular disk 10. Have.

The sleeve 9 has a small-diameter end rotatably inserted into the other divided end of the camshaft 3 and is fitted on the outer periphery of the drive shaft 2 and penetrates in a diametrical direction. It is connected and fixed to the drive shaft 2 via a connecting pin 12. A flange 13 provided at the other end of the sleeve 9 is opposed to the flange 8 on the camshaft 3 side, and as shown in FIG. A mating groove 14 is formed,
The outer peripheral surface has a flange surface 9a that slides on the other surface of the annular disk 10. The engagement groove 14 is disposed on the opposite side of the camshaft 3 side flange portion 8 from the engagement groove 11 by 180 °.

The annular disk 10 has a substantially donut plate shape, an inner diameter substantially equal to the inner diameter of the camshaft 3, and an annular gap S formed between the annular disk 10 and the outer peripheral surface of the drive shaft 2. At the same time, a small-width outer peripheral portion 10a is rotatably held on the inner peripheral surface of the control ring 16 via an annular bearing metal 15. Further, holding holes 10b and 10c are formed to penetrate at opposite positions on diameter lines different from each other by 180 °, and a pair of holding holes 10b and 10c are engaged with the engagement grooves 11 and 14 respectively. Pins 17 and 18 are fitted and arranged.

The pins 17 and 18 protrude in the axial direction of the camshaft 3 in opposite directions, and a base formed of a cylindrical surface is rotatably fitted and supported in the holding holes 10b and 10c. As shown in FIGS. 5 and 6, each of the engaging grooves 1 is provided at a tip end projecting from the surface of the annular disk 10.
The two flat surfaces 17a, 17b, 18a, 1 that come into contact with the opposing inner surfaces 11a, 11b, 14a, 14b
8b are respectively formed.

The positioning of the pins 17 and 18 in the axial direction is performed in the projecting direction by the steps 17c and 17c formed between the cylindrical surfaces of the pins 17 and 18 and the flat portions 17a, 17b, 18a and 18b. 18c and the flange surfaces 8a, 9a, and in the retreating direction, the holding hole 10
b, the base end faces 17d of the pins 17, 18 penetrating the 10c,
The contact between 18d and the flange surface 9a, 8 a, is performed respectively.

The control ring 16 has a substantially annular shape and, as shown in FIG. 3, has a boss 16a on a part of its outer periphery, and is driven around a swing shaft 19 passing through the boss 16a as a fulcrum. It is configured to be swingable up and down along a plane orthogonal to the axial direction of the shaft 2. A lever 16b is provided on the outer peripheral surface on the side opposite to the boss 16a so as to protrude in the radial direction. When the drive mechanism 28 described later operates the lever 16b, the swing position of the control ring 16 is changed. It is controlled.

As shown in FIG. 3 and FIG. 7, a lubricating oil passage 20 through which lubricating oil is fed from an oil gallery of the engine is provided inside the oscillating shaft 19. The sliding surface between the bearing metal 15 and the annular disk 10 is lubricated through the portions 22 and 23. An oil groove 24 communicating with the oil supply hole 22 is formed on the outer peripheral surface of the annular disk 10, so that the lubricating oil spreads over the entire circumference of the annular disk 10. Also, this oil groove 24
As shown in FIG. 3 , the holding holes 1 of the pins 17 and 18 are
Oil supply holes 25 are formed toward 0b and 10c. By these lubrication mechanisms, the annular disk 10 and the control ring 16
And between the annular disk 10 and the pins 17, 18 are forcibly lubricated.

As shown in FIG. 2, an oil supply pipe 26 is disposed above the drive shaft 2 and the camshaft 3 along the axial direction thereof. An oil supply hole 27 is formed in the vicinity of the boundary between the oil supply hole and the annular disk 10. Engine lubricating oil is also supplied to the oil supply pipe 26 by pressure. Lubricating oil supplied from an oil supply hole 27 lubricates between the pins 17 and 18 and the engagement grooves 11 and 14. .

The drive mechanism 28 for swinging the control ring 16 includes
As shown in FIG. 3, first and second cylinders 29 and 30 formed opposite to each other at predetermined portions of a cylinder head, and a hydraulic piston 31 and a retainer 32 fitted in the respective cylinders 29 and 30 so as to be freely retractable. , As shown in FIG.
A hydraulic circuit 33 for supplying and discharging hydraulic pressure to a hydraulic chamber 29 a defined in the cylinder 29 to move the hydraulic piston 31 forward and backward. The hydraulic piston 31 and the retainer 32
The lever portion 1 is opposed to each other and between the two ends.
The arc-shaped tip portion 6b is sandwiched from above and below.

Here, the retainer 32 provided in the second cylinder 30 is formed in a substantially cylindrical shape with a bottom, and is attached in a projecting direction by the spring force of a coil spring 34 provided in the second cylinder 30. It is being rushed. The retracted position of the hydraulic piston 31 is regulated by contacting the bottom surface of the first cylinder 29. At the maximum retracted position contacted with the bottom surface, the hydraulic piston 31 and the rotational center Y of the annular disk 10 are in contact with each other. The drive shaft 2 is set so as to be concentric with the center X of the drive shaft 2.

The hydraulic circuit 33 includes an oil passage 36 having one end communicating with the oil pan 35 of the engine, the other end communicating with the hydraulic chamber 29a, and an oil passage provided on the oil pan 35 side of the oil passage 36. It mainly comprises a pump 37 and a three-port two-position solenoid valve 38 provided downstream of the oil pump 37. The hydraulic circuit 33
Is generally configured using an engine lubrication system, and the oil pump 37 and the like are shared with the engine lubrication system.

A crank angle sensor 39 detects the crank angle of the engine, an air flow meter 40 detects the intake air amount, and a water temperature sensor 41 detects the cooling water temperature of the engine. , 41 are connected to a controller 42.

The controller 42, which is a control means for centrally controlling the engine, is configured as a microcomputer system, and determines the operating state of the engine based on detection signals from the sensors 39, 40, 41, as described later. A control signal is output to the solenoid valve 38 and another solenoid valve 54 to be described later according to the operating state, and these are switched.

The controller 42 performs duty control at an intermediate stage when switching between the solenoid valves 38 and 54. That is, for example, O
When switching from N signal to OFF signal, output 10
From the 0% state, the ON time ratio is gradually reduced within a predetermined short time, and conversely, when switching from the OFF signal to the ON signal, the output is 0% within the predetermined short time. Gradually increase the ratio of the ON time. Thus, the pressure of the hydraulic oil supplied through the solenoid valves 38 and 54 changes substantially continuously in a stepwise manner.

Next, referring to FIG. 8, the second variable valve mechanism 4
3 will be described.

First, FIG. 8 is an enlarged sectional view showing the details of the second variable valve mechanism 43. The first variable valve mechanism 43 includes a sleeve 44, an inner cylinder 45, and an outer Cylinder 4
7, and a piston 48 and the like.

That is, the sleeve 44 is rotatably inserted into the front end of the camshaft 3 and is connected to the drive shaft 2 by the connecting pin 1.
2 is fixed. An inner cylinder 45 is fixed to the front end of the sleeve 44 via a mounting bolt 46, and a cup-shaped outer cylinder 47 integrally formed with a cam pulley 47a is formed on the outer peripheral side of the inner cylinder 45 by, for example, about 10 °. It is fitted so as to be relatively rotatable.

A ring-shaped piston 48 is provided between the inner cylinder 45 and the outer cylinder 47. The piston 48 is connected to the outer peripheral surface of the inner cylinder 45 and the outer periphery of the outer cylinder 47 through a helical thread. Face and each other.

Further, the piston 48 is constantly urged forward by a return spring 49. To counter this spring force, a hydraulic pressure is applied between the front surface of the piston 48 and the back surface of the lid of the outer cylinder 47. A chamber 50 is defined. The hydraulic chamber 50 is provided with an oil passage 51 in the mounting bolt 46.
As shown in FIG. 1, a hydraulic circuit 5 for the second variable valve mechanism 43 is formed through an oil passage 52 formed to the inside of the sleeve 44.
3 is connected to the solenoid valve 54. Then, the hydraulic circuit 53 is controlled by the second
The working oil pressure is supplied to the variable valve mechanism 43.

Next, the operation of the first variable valve mechanism 1 will be described with reference to FIG.

First, when the controller 42 outputs an OFF signal to the electromagnetic valve 38, the oil passage 36 and the oil pan 35 are connected via the electromagnetic valve 38. As a result, the hydraulic pressure in the hydraulic chamber 29a is released, and the hydraulic piston 31 is retracted to the maximum retracted position where it contacts the bottom surface of the first cylinder 29 by the spring force of the valve spring 5 and the coil spring 34.

Therefore, the control ring 16, that is, the annular disc 1
The rotation center Y of 0 and the center X of the drive shaft 2 match. That is, the state shown by the solid line in FIG. 3 is obtained. In this case, there is no rotational phase difference between the annular disk 10 and the drive shaft 2, and the center Y of the camshaft 3 and the center Y of the annular disk 10 also match. Does not occur.

Therefore, the drive shaft 2, the annular disk 10 and the camshaft 3 rotate synchronously at a constant speed via the pins 17 and 18. As a result, valve lift characteristics along the cam profile as shown by the solid line in FIG. 9A are obtained. At this time, substantially no slippage occurs between the pins 17 and 18 and the engagement grooves 11 and 14.

On the other hand, when an ON signal is output from the controller 42 to the solenoid valve 38, the solenoid valve 38 is switched, and the hydraulic oil from the oil pump 37 is supplied to the hydraulic chamber 29a via the oil passage 36, and the hydraulic chamber 29a Internal pressure rises.

As the pressure rises, the hydraulic piston 31 pushes up the lever portion 16b to a predetermined position against the spring force of the coil spring 34, as shown by the one-dot chain line in FIG. It swings upward with the fulcrum 19 as a fulcrum, and the center Y of the annular disk 10 is eccentric from the center X of the drive shaft 2 as shown by Y 'in FIG.

In this state, the sliding position between the engaging groove 14 of the sleeve 9 and the pin 18 and the sliding position between the engaging groove 11 of the camshaft 3 and the pin 17 are all the same.
The rotation is performed at every rotation of the circular disk 10 and the angular velocity of the annular disk 10 is changed.

In particular, in an angular region where the sliding position between one locking groove 14 and the pin 18 approaches the center X of the drive shaft 2, the sliding position between the other locking groove 11 and the pin 17 is separated from the center X. Become a relationship. In this case, the annular disk 10 has a small angular velocity with respect to the drive shaft 2, and further has the annular disk 1.
The angular velocity of the camshaft 3 becomes smaller than zero. Therefore, the angular velocity of the camshaft 3 is 2
It becomes a state of heavy deceleration.

Conversely, in the angular region where the sliding position between one locking groove 14 and the pin 18 is separated from the center X of the drive shaft 2, the sliding position between the other locking groove 11 and the pin 17 is located at the center X. A close relationship. In this case, the angular velocity of the annular disk 10 with respect to the drive shaft 2 increases, and the angular velocity of the camshaft 3 with respect to the annular disk 10 also increases. Therefore, the angular velocity of the camshaft 3 is doubled with respect to the drive shaft 2.

As a result, a relatively large phase difference is provided between the drive shaft 2 and the camshaft 3 as shown by a dashed line in FIG. 9B. Further, an in-phase point (point P) exists midway between the maximum and minimum points of the rotational phase difference. Note that FIG.
In the characteristic diagram of (B), the phase difference in the direction in which the camshaft 3 relatively advances is positive, and the phase difference in the direction in which the camshaft 3 is relatively slow is negative.

The opening timing of the intake valve 4 located in the region where the camshaft 3 is relatively delayed is delayed by the phase difference. Conversely, the closing timing of the intake valve 4 located in the region where the camshaft 3 is relatively advanced advances with the phase difference. Therefore, FIG.
The valve lift characteristic as shown by the one-dot chain line is obtained in (A), and the operating angle is reduced.

Here, as shown in FIG. 9, the lift start point Q ₁ at the time of the above-described coaxial operation is set to be immediately after the in-phase point P. Thereby, the lift start point Q at the time of eccentricity
₂ whereas faster by rotational phase difference [delta] ₁ than the lift start point to Q ₁ when coaxial, lift the end point R ₂ when the eccentric is made as soon as the rotational phase difference [delta] ₂ than the lift end point R ₁ at coaxial.

Next, the operation of the second variable valve mechanism 43 will be described.

First, the controller 42 sets another electromagnetic valve 54
Output an OFF signal to the hydraulic chamber 50 and the oil pan 3
5 is connected. As a result, the pressure in the hydraulic chamber 50 is released, and the piston 48 does not move in the axial direction. Therefore, the inner cylinder 45 and the outer cylinder 47 do not rotate relative to each other, and the phase angle of the drive shaft 2 and the phase angle of the crankshaft Matches. Here, the opening and closing timing of the intake valve 4 is set to be delayed as a whole when there is no phase difference between the drive shaft 2 and the crankshaft.

On the other hand, when an ON signal is output from the controller 42 to the electromagnetic valve 54, the electromagnetic valve 54 is switched, and the hydraulic oil from the oil pump 37 is supplied into the hydraulic chamber 50 via the oil passage 52 and the like. As a result, the piston 48 moves in the axial direction, and the movement in the axial direction is performed by the inner cylinder 45 and the outer cylinder 4.
7 is converted into a relative rotational motion. Therefore, the drive shaft 2
A difference occurs in the phase angle between the intake valve 4 and the crankshaft, and as shown by a solid line waveform and a dotted line waveform in FIG. 11, the operating center angle itself of the intake valve 4 moves, and both the opening timing and the closing timing are advanced or delayed. I do.

Next, the operation of the entire variable valve apparatus will be described in detail with reference to FIGS.

First, the controller 42 has an operation switching map as shown in FIG. 10, and the valve timing of the intake valve 4 is controlled based on this map. This operation switching map is divided into three areas: a low load area A, a low rotation high load area B, and a high rotation high load area C.

The controller 42 controls each sensor 3
Based on the detection signals of 9, 40 and 41, the engine speed and torque are detected, and it is determined which of the areas A, B and C the operating state of the engine is in. B,
In response to C, a control signal is output to each of the electromagnetic valves 38 and 54 to operate each of the variable valve mechanisms 1 and 43.

First, when the engine is in the low load area A, the controller 42 outputs an OFF signal to the solenoid valve 38 to make the center Y of the annular disk 10 coincide with the center X of the drive shaft 2 and to rotate the engine. The phase difference is set to zero, and the operating angle of the intake valve 4 is set to the large operating angle α when coaxial. On the other hand, the controller 42 also outputs an OFF signal to the other solenoid valves 54 to set the operation center angle to the lag side so that no phase difference occurs between the drive shaft 2 and the crankshaft. 11, a valve timing a at a low load is obtained as shown by a solid line waveform in FIG. Therefore, the opening timing and the closing timing of the intake valve 4 are both greatly delayed, and the overlap is small or no longer occurs.

Next, when the load on the engine rises and enters the low-speed high-load region B, the controller 42 keeps the second variable valve mechanism 43 in the low-load region A while maintaining the same. An ON signal is output only to the solenoid valve 38 to swing the control ring 16 so that the annular disk 10 is eccentric with respect to the drive shaft 2 and the operating angle of the intake valve 4 is switched to the small operating angle β at the time of eccentricity. Thereby, both the opening timing and the closing timing are advanced while the operating angle of the intake valve 4 is narrowed, and the valve timing b at the time of low rotation and high load is obtained as shown by the one-dot chain line waveform in FIG. Therefore, while the overlap occurs moderately, the closing timing is greatly advanced. Here, as described above, when the operating angle is switched from the large operating angle α to the small operating angle β by the first variable valve mechanism 1, duty control is performed, so that the operating angle of the intake valve 4 is substantially It is switched continuously.

Further, when the engine enters the high-speed high-load region C, the controller 42 turns on the other solenoid valves 54.
A signal is output to generate a phase difference between the drive shaft 2 and the crankshaft to advance the operating center angle of the intake valve 4. On the other hand, the controller 42 outputs an OFF signal to the solenoid valve 38 of the first variable valve mechanism 1, returns the relationship between the annular disk 10 and the drive shaft 2 to the same axis, and switches the operation angle to the large operation angle α. As a result, while the opening timing is greatly advanced, the closing timing is positioned approximately in the middle between the low load state and the low rotation high load state, and as shown by the dotted line waveform in FIG. The timing c is obtained. Here, as described above, when the operating angle and the operating center angle are switched, duty control is performed.
Microscopically, it changes stepwise, and macroscopically, it changes smoothly and continuously.

The above results are summarized in Table 1 below.

[0076]

[Table 1]

As described above, according to this embodiment, the first variable valve mechanism 1 in which the drive shaft 2 and the camshaft 3 are connected by the swingable annular disk 10, the inner cylinder 45 and the outer cylinder 47
And the second variable valve mechanism 43 that changes the phase angle between the drive shaft 2 and the crankshaft by the relative rotation of the variable valve mechanism 43, the hydraulic oil supplied to each variable valve mechanism 1, 43 By controlling, the operating angle and opening / closing timing of the intake valve 4 can be changed by the first variable valve mechanism 1, and the operating center angle of the intake valve 4 can be changed by the second variable valve mechanism 43. Can be. As a result,
Various valve timings according to the operating state of the engine can be easily obtained.

Further, as shown in Table 1 and FIG. 11, the variable valve mechanisms 1 and 43 are operated in accordance with the operating state of the engine, and the valve timing a at low load and the valve timing at low rotation and high load are set. (b) Since the valve timing c at the time of high rotation and high load is obtained, fuel efficiency can be improved at low load and output can be increased at high load.

That is, in the low load region A, since the closing timing of the intake valve 4 is greatly delayed until the middle of the top dead center (TDC) and the bottom dead center (BDC), the air-fuel mixture once sucked into the combustion chamber is re-exposed. The fuel is returned to the intake pipe to reduce the suction amount, and the pumping loss is greatly reduced, thereby improving fuel efficiency. On the other hand, since the opening timing of the intake valve 4 is delayed and the valve overlap is small or does not occur, the residual gas in the combustion chamber can be reduced to stabilize the combustion state.
Fuel efficiency is improved.

In the low-rotation, high-load region B, the intake valve 4
The opening timing is earlier than when the load is low, an appropriate overlap occurs, the exhaust efficiency increases, and the output increases. On the other hand, since the closing timing of the intake valve 4 is greatly advanced, the air-fuel mixture charging efficiency at low rotations is increased, and the output is also increased.

Further, in the high rotation and high load region C, the closing timing of the intake valve 4 is relatively late, so that the charging efficiency at the time of high rotation is increased, while the opening timing of the intake valve 4 is greatly advanced and the valve overlap is increased. , The exhaust efficiency also increases. Therefore, in this case, the output is improved.

On the other hand, in this embodiment, the first variable valve mechanism 1 capable of adjusting both the operating angle and the opening / closing timing by adjusting the swinging direction of the annular disk 10 and the positional relationship between the cam 7 and the like.
By operating only the first variable valve mechanism 1, the valve timing a at the time of low rotation
And the valve timing b at low rotation and high load can be quickly switched.

That is, as shown in FIG. 9A, when the first variable valve mechanism 1 reduces the operating angle to a small operating angle β, the lift start point Q ₂ is coaxial (large operating angle α). Time)
Because it is set to be earlier than the lift start point to Q _1, by the operation of a single variable valve mechanism 1, it can be accelerated relatively also open timing with advancing large closing timing of the intake valve 4 .

Therefore, between the low-load region A and the low-rotation high-load region B, which frequently switch in the actual operation state,
The valve timings a and b can be switched quickly and stably, and there is no need to excessively increase the capacity of the oil pump 37, so that fuel efficiency is further improved. On the other hand, according to the device described in the publication described in the prior art, although two types, a high-speed cam and a low-speed cam, can be selected, only the operating angle and the lift amount can be adjusted. Therefore, the transition between the low-load region A and the low-rotation high-load region B cannot be performed only by switching the cam, and the phase angle between the crankshaft and the drive shaft 2 also needs to be adjusted. I do. However, in this embodiment, since only the first variable valve mechanism 1 needs to be operated, the configuration is simple and stable valve timing control can be performed.

The low load area A and the high rotation high load area C
As shown in Table 1, it is sufficient to adjust only the operating center angle of the intake valve 4 by the second variable valve operating mechanism 43, as shown in Table 1. Therefore, the same effect as above, that is, the predetermined valve timing Can be obtained stably and reliably.

In this embodiment, each variable valve mechanism 1,
Since the pressure of the hydraulic oil is changed substantially smoothly by performing the duty control when switching 43, the torque shock at the time of switching the valve timing can be greatly reduced, and the drivability can be improved. .

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 12 shows an operation switching map according to the present embodiment, in which the low load area A and the low rotation high load area B are used.
And a first intermediate region D, and a low load region A
A second intermediate region E is arranged between the high-speed and high-load region C.

In the first intermediate area D, the first
The ON time ratio of the duty control to the solenoid valve 38 of the variable valve mechanism 1 is set to an intermediate value M ₁ % which is an arbitrary value between 0 and 100% (however, the lower limit is 0% and the upper limit is 10%).
(Except 0%, for example, it is set in the range of about 20 to 80%, and preferably in the range of about 40 to 60%). Generate an intermediate operating angle γ (not shown) between the operating angle β and
The transition between the two areas A and B is made stepwise.

On the other hand, in the second intermediate region E, the ON time ratio of the duty control when the second variable valve mechanism 43 shifts to the solenoid valve 54 is an arbitrary value between 0 and 100%. Intermediate value of M ₂ % (however, similar to M ₁ , for example, in the range of about 20 to 80%, preferably 40 to 60%
Is set in the range of about), an intermediate operating center angle between a slow operating center angle at a low load and a fast operating center angle at a high rotation and a high load is generated. Is to be shifted step by step.

In this embodiment having such a configuration, substantially the same effects as in the first embodiment can be obtained. In addition, in this embodiment, in particular, in the present embodiment, the duty control is performed in three stages when switching the valve timing. Therefore, although the smoothness at the time of shifting is somewhat lacking strictly, there is no practical problem. Rather, the control can be further simplified while maintaining the basic effects.

Next, FIG. 13 shows a third embodiment of the present invention. In this embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals,
The description is omitted.

That is, in the present embodiment, the phases of the pins 17 and 18 with respect to the profile of the cam 7 are different from those of the first embodiment by 180 °, whereby the annular disk 10 is connected to the drive shaft 2. On the other hand, when the eccentric state is established, the operating angle is widened. Even if the eccentric direction is reversed without changing the phase relationship between the cam 7 and the pins 17 and 18, the operating angle similarly increases. And
In this embodiment, the lift start point to Q ₁ when coaxial (when a small operating angle beta), and set immediately after the in-phase point P when the phase difference of the camshaft 3 is changed from positive to negative with respect to the drive shaft 2 I have.

In this embodiment having such a configuration, substantially the same effects as those in the first embodiment can be obtained.

In each of the above embodiments, the case where the present invention is applied only to the drive of the intake valve 4 is exemplified. However, the present invention is not limited to this, and can be applied to the exhaust valve.

In each of the above embodiments, each solenoid valve 38,
By performing duty control on the voltage applied to 54,
Although it has been described that the operating oil pressure is substantially continuous or that the intermediate values M ₁ and M ₂ are obtained, other means such as providing a variable throttle in a hydraulic circuit may be used instead.

[0097]

As is apparent from the above description, according to the variable valve apparatus for an internal combustion engine according to the present invention, for example, the drive shaft and the camshaft are connected by a swingable annular disk. > a Ri, cam with respect to the rotation of the drive shaft in accordance with the engine operating condition
A first variable valve mechanism for changing the angular velocity of the shaft ;
Second to change the phase angle between the drive shaft and the crankshaft
By configuring the variable valve mechanism with the variable valve mechanism, by controlling the hydraulic oil supplied to each variable valve mechanism,
Various valve timings according to the operating state of the engine can be easily obtained.

[0098] Then, it is possible to set the valve timing in accordance with the operating state of the engine, can improve fuel efficiency in the low-load state, further, when migrating between the low-load region and the low speed and high load range Since only the first variable valve mechanism capable of simultaneously adjusting both the operating angle and the opening / closing timing needs to be operated, the valve timing can be set stably and promptly. Further, according to the configuration of the second aspect, a high load
The output in the state can be improved.

Furthermore, according to the third to sixth aspects, the torque shock at the time of transition can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing the entire configuration of a variable valve operating device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway view showing a main part of a first variable valve mechanism.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a plan view showing a main part of a first variable valve apparatus.

FIG. 5 is a sectional view taken along the line BB in FIG. 4;

FIG. 6 is a sectional view taken along the line CC in FIG. 4;

FIG. 7 is a sectional view taken along the line DD in FIG. 3;

FIG. 8 is a sectional view showing a main part of a second variable valve mechanism.

FIG. 9 is a characteristic diagram showing a rotational phase difference characteristic between a drive shaft and a camshaft and a valve lift characteristic in comparison.

FIG. 10 is an explanatory diagram showing a map for switching a control operation according to an operating state of the engine.

FIG. 11 is a characteristic diagram showing the relationship between the valve timing of an intake valve and the valve timing of an exhaust valve according to the operating state of the engine.

FIG. 12 is an explanatory diagram showing an operation switching map according to a second embodiment of the present invention.

FIG. 13 is a characteristic diagram showing a rotational phase difference between a drive shaft and a camshaft and a valve lift characteristic in comparison with a third embodiment of the present invention.

FIG. 14 is a characteristic diagram showing valve timings of an exhaust valve and an intake valve according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st variable valve apparatus 2 ... Drive shaft 3 ... Camshaft 4 ... Intake valve 8, 13 ... Flange part 10 ... Annular disk 11, 14 ... Engagement groove 17, 18 ... Pin 28 ... Drive mechanism 42 ... Controller 43... Second variable valve mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/34 F02D 13/02

Claims (7)

(57) [Claims] And 1. A drive shaft which rotates in synchronism with rotation of the engine, is disposed on the drive shaft coaxially and a cam shaft having the outer periphery of the cam for driving the intake and exhaust valves, according to the engine operating condition Camshaft against rotation of drive shaft
And a second variable valve mechanism that changes the phase angle of the drive shaft with respect to the crankshaft of the engine , and the engine is in a low load region. When the first variable movement
While increasing the operating angle of the intake valve via the valve mechanism,
The opening / closing timing of the intake valve is delayed through the second variable valve mechanism.
A first control to be performed, and the first variable control when the engine is in a low rotation high load region.
The operating angle of the intake valve is controlled via the valve operating mechanism in the first control mode.
Opening and closing timing of intake valve
From the state of the first control, and
Is maintained in the same state as the first control.
And a control means for performing the second control.
The variable valve device for an internal combustion engine that. 2. The control means, when the engine is in a high-speed, high-load region, increases the operating angle of an intake valve via the first variable valve mechanism and controls the second variable valve mechanism. Control is performed to advance the opening / closing timing of the intake valve through the
Cormorant it variable valve device for an internal combustion engine according to claim 1, wherein the. 3. The control means, when the engine is in an intermediate region between the low load region and the low rotation high load region, adjusts an operating angle of an intake valve via the first variable valve mechanism. 3. The variable valve actuation device for an internal combustion engine according to claim 2, wherein a fourth control is performed to set an intermediate value between an operation angle in a low load region and an operation angle in a low rotation and high load region. . 4. The control means, when the engine is in an intermediate region between the low load region and the high rotation and high load region, lowers an opening / closing timing of an intake valve via the second variable valve mechanism. 3. The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein a fifth control is performed to set an intermediate phase between an opening / closing timing in a load region and an opening / closing timing in a high-speed high-load region. 5. The control means according to claim 1, wherein when the operating condition of the engine moves between the low load region and the low rotation high load region, the operating angle of the intake valve is adjusted by the first variable valve mechanism. 3. The variable valve train of an internal combustion engine according to claim 2, wherein the operation angle is changed substantially continuously between an operation angle in a low load region and an operation angle in a low rotation high load region. apparatus. 6. The control means controls the second variable valve mechanism to open and close an intake valve when an operating condition of the engine moves between the low load region and the high rotation high load region. 3. The variable valve of an internal combustion engine according to claim 2, wherein the opening and closing timing in the low load region and the opening and closing timing in the high rotation and high load region are changed substantially continuously. apparatus. 7. The camshaft according to claim 1, wherein the first variable valve mechanism is a camshaft.
At the end of the slot, and the engagement groove is formed in the radial direction.
One of the formed flanges and the other
Provided on the drive shaft side so as to face each other and in the radial direction
The other flange portion having an engagement groove formed along the
An annular disk that is swingably arranged between both flanges
And projecting in opposite directions on both sides of this annular disc
And are respectively engaged in the respective engagement grooves of the both flange portions.
The pin and the annular disk are swung according to the engine operating condition.
And a drive mechanism for causing
7. The variable valve train for an internal combustion engine according to any one of 6.