JP2001012262A - Variable valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit the fluctuation of an operating angle by setting and outputting the driving current on the basis of the reaction torque equivalent current acting on a control shaft from an engine side and operated on the basis of a cam angle of a cam shaft operated on the basis of the number of revolution of the engine, and the operated current control amount. SOLUTION: As the reaction torque is synchronized with a cam angle of a cam shaft, a calculated value of the reaction torque to the cam angle is stored in a reaction torque equivalent current operating means B7 in advance. The reaction torque at that time can be immediately judged on the basis of the cam angle of the cam shaft operated by the cam angle operating means B6 on the basis of the detected number of revolutions of the engine, and the reaction torque equivalent current value can be easily determined on the basis of the reaction torque. The necessary current control amount operated by a current control operating means B5 is corrected on the basis of the reaction torque equivalent current value to make a target control shaft operating angle determined by a target operating angle operating means B3 on the basis of the number of revolutions of the engine and the engine load agree with the control shaft actual operating angle detected by a operating angle detecting means B4, and the driving current to a DC servo motor is determined and output to a PWN output determining means B8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve operating device for an internal combustion engine that can vary the lift amount (operating angle of a control shaft) of an intake / exhaust valve of the internal combustion engine according to the operating state of the engine.

[0002]

2. Description of the Related Art As is well known, in order to improve fuel efficiency at low engine low 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, intake air intake and air intake are controlled. Various variable valve devices for variably controlling the opening / closing timing of an exhaust valve and the valve lift amount according to the engine operating state have been conventionally provided.
Japanese Patent No. 137305 is known.

Referring to FIG. 17, the camshaft 2 is provided at a position substantially above the center of the upper deck of the cylinder head 1, and a cam 2 a is integrally provided on the outer periphery of the camshaft 2. ing. A control shaft 3 is arranged in parallel on the side of the cam shaft 2.
A rocker arm 5 is pivotally supported via an eccentric cam 4.

On the other hand, at the upper end of an intake valve 6 slidably provided on the cylinder head 1, a swing cam 8 is arranged via a valve lifter 7. The swing cam 8 is swingably supported by a support shaft 9 disposed above the valve lifter 7 in parallel with the cam shaft 2, and a lower cam surface 8 a is in contact with the upper surface of the valve lifter 7. . The rocker arm 5 has one end 5a abutting on the outer peripheral surface of the cam 2a and the other end 5b abutting on the upper end surface 8b of the swing cam 8, thereby lifting the lift of the cam 2a. And, it transmits to the intake valve 6 via the valve lifter 7. The intake valve 6 is urged in a valve closing direction by a valve spring 6a.

Further, as shown in FIG. 18, the control shaft 3 is controlled by an electromagnetic actuator such as a DC servomotor.
The eccentric cam 4 is rotated and driven within a predetermined angle range via a reduction gear, thereby controlling the rotation position of the eccentric cam 4, thereby changing the swing fulcrum of the rocker arm 5.

In FIG. 17, when the eccentric cam 4 is controlled to a predetermined rotation position in the normal and reverse directions, the swing fulcrum of the rocker arm 5 changes, and the upper end face 8b of the swing cam 8 at the other end 5b.
Is changed in the vertical direction in the figure, whereby the swing locus of the swing cam 8 changes with the change of the contact position of the cam surface 8a of the swing cam 8 with the upper surface of the valve lifter 7. The opening / closing timing of the intake valve 6 and the valve lift amount are variably controlled according to a change in the operating angle of the control shaft 3. Reference numeral 10 in the drawing indicates a spring that constantly biases the upper end surface 8b of the swing cam 8 against the other end 5b of the rocker arm 5.

Further, as described above, in a variable valve operating apparatus having a configuration in which the opening / closing timing and valve lift of the intake valve 6 are variably controlled by changing the swing fulcrum of the rocker arm 5, As shown in the system diagram of FIG. 10, the operating angle of the control shaft 3 for changing the swing fulcrum is detected by an operating angle sensor such as a potentiometer, and based on the detected operating angle signal, the control device In the position servo controller (linear controller), the detected operating angle signal is compared with the target control axis operating angle, and the DC servo motor is connected to the DC servo motor via PWM (pulse width modulation) output setting means so that the difference becomes zero. By outputting the drive current, the operating angle of the control shaft 3 is adjusted to the target control shaft operating angle corresponding to the target valve characteristic. Scan and the feedback control had come to be carried out.

[0008]

However, in the above-described conventional apparatus, as described above, the position servo controller uses the feedback based on the operating angle only based on the information on the target control axis operating angle and the detected operating angle. Since the back control is performed, there are problems as described below.

That is, as described above, the rocker arm 5 is pivotally supported by the control shaft 3 via the eccentric cam 4, and one end 5a of the rocker arm 5 is in contact with the outer peripheral surface of the cam 2a. At the same time, the other end 5b is connected to the upper end face 8 of the swing cam 8.
b, the lift of the cam 2a is transmitted to the intake valve 6 via the swing cam 8 and the valve lifter 7, so that the reaction force torque due to the reaction force of the valve spring 6a is reduced. Is transmitted to the control shaft 3 as disturbance via the valve lifter 7, the swing cam 8 and the rocker arm 5.

In the feedback control of the control shaft operating angle, since the control based on the operating angle has a large control delay, during the fixed position control in which the operating angle is maintained at the predetermined angle position, the control shown in FIG. As shown in the figure, a control deviation based on the reaction torque is generated.
When the engine speed is high, a control deviation based on the reaction torque appears remarkably, which impairs the control accuracy of the variable valve device, and provides a sufficient effect of improving the engine output and reducing the fuel consumption. Disappears.

The present invention has been made in view of the above-mentioned conventional problems, and is caused by a valve spring reaction force transmitted to a control shaft through a cam, a rocker arm, or the like during control of the control shaft operating angle at a fixed position. By suppressing the fluctuation of the operating angle generated based on the reaction torque (variable for each engine speed and operating angle) which is a non-linear characteristic, it is possible to prevent a decrease in control accuracy, thereby achieving a sufficient engine output improving effect and It is an object of the present invention to provide a variable valve operating device for an internal combustion engine capable of reducing fuel consumption, and to obtain a more stable operation angle fluctuation suppressing effect by absorbing a control deviation due to a reaction torque different for each cylinder. It is for an additional purpose.

[0012]

According to a first aspect of the present invention, there is provided a variable valve apparatus for an internal combustion engine, comprising: a control shaft disposed substantially parallel to a cam shaft; A control cam eccentrically fixed to the outer periphery of the shaft, a rocker arm pivotally supported by the control cam, and a rocking drive means for rocking one end of the rocker arm in accordance with the rotation of the cam shaft A swing cam that swings in association with the other end of the rocker arm to open the engine valve, a valve spring that biases the engine valve in a closing direction, and detects an operating angle of the control shaft. Operating angle detecting means, an electromagnetic actuator for rotating the control shaft to a target control axis operating angle, engine speed detecting means for detecting the engine speed, and a target control shaft operating angle according to the operating state of the engine. Target operating angle calculating means for calculating; Current control amount calculating means for calculating a current control amount required to make the target control axis operating angle calculated by the operating angle calculating means coincide with the control axis actual operating angle detected by the operating angle detecting means; A cam angle calculating means for calculating a cam angle of the cam shaft from an engine speed detected by the engine speed detecting means; and a cam shaft calculated from the cam angle calculated by the cam angle calculating means to a control shaft from the engine side. Reaction torque equivalent current calculating means for calculating a reaction torque equivalent current to act on;
Output setting means for setting and outputting a drive current for the electromagnetic actuator based on the reaction torque equivalent current calculated by the reaction torque equivalent current calculation means and the current control amount calculated by the current control amount calculation means. That means.

According to a second aspect of the present invention, there is provided a variable valve operating system for an internal combustion engine according to the first aspect.
An engine load detecting means for detecting a load of the engine, wherein the target operating angle calculating means calculates an engine load based on an engine speed detected by the engine speed detecting means and an engine load detected by the engine load detecting means. The means is configured to calculate a target control shaft operating angle according to the operating state of the engine.

According to a third aspect of the present invention, in the variable valve operating apparatus for an internal combustion engine according to the first or second aspect, the cam angle of the cam shaft calculated by the cam angle calculating means is provided. The engine further comprises cylinder-specific reaction torque coefficient calculating means for determining a cylinder in which the engine valve is currently open and calculating a reaction torque coefficient for each cylinder, wherein the output setting means calculates the reaction torque coefficient for each cylinder. A current value obtained by multiplying the reaction torque coefficient of the open cylinder determined by the means by the reaction torque equivalent current calculated by the reaction torque equivalent current calculation means, and a current control amount calculated by the current control amount calculation means. Means for setting and outputting a drive current to the electromagnetic actuator based on the above.

[0015]

In the variable valve operating apparatus for an internal combustion engine according to the present invention, the target operating angle is calculated by the target operating angle calculating means based on the operating angle signal of the control shaft detected by the operating angle detecting means. Feedback control of the drive current to the electromagnetic actuator is performed so as to rotate and drive to the target control shaft operating angle according to the operating state of the engine.

The current control amount calculating means calculates a current control amount required to make the target control axis operating angle coincide with the control shaft actual operating angle. Then, a reaction torque equivalent current acting on the control shaft from the engine side is calculated from the cam angle of the cam shaft calculated by the cam angle calculation means, and the subsequent output setting means calculates the reaction torque equivalent current and the current. The setting and output of the drive current to the electromagnetic actuator are performed based on the current control amount calculated by the control amount calculation means.The current control amount calculation means uses an operation angle based on a change in a target control axis operation angle as a base. The control shaft operating angle is controlled, and the reaction torque equivalent current calculation means performs correction control to cancel the effect of the reaction torque, thereby controlling the control shaft operating angle at a fixed position. In order to suppress the operating angle fluctuation generated based on the reaction torque (variable for each engine speed and operating angle), which is a non-linear characteristic due to the valve spring reaction force transmitted to the control shaft through the cam and the rocker arm, etc. Works.

According to a third aspect of the present invention, in the variable valve operating apparatus for an internal combustion engine, in the cylinder-specific reaction torque coefficient calculating means, the current engine valve is opened based on the cam angle of the cam shaft calculated by the cam angle calculating means. The cylinders that are present are determined, the reaction torque coefficient of each cylinder is calculated, and the output setting means calculates the reaction torque coefficient of the determined open-operation cylinder by the reaction force calculated by the reaction torque equivalent current calculation means. The drive current for the electromagnetic actuator is set based on the current value multiplied by the torque-equivalent current and the current control amount calculated by the current control amount calculation means, whereby the reaction torque is set for each cylinder of the engine. The control deviation between each cylinder due to the difference is absorbed,
More stable operation angle fluctuation suppression is performed.

[0018]

Embodiments of the present invention will be described below. (First Embodiment of the Invention) FIGS. 1 to 3 show a variable valve apparatus of an internal combustion engine (engine) according to a first embodiment of the present invention, in which two intake valves are provided for each cylinder. This will be described below as a variable valve mechanism VEL (hereinafter, referred to as a VEL mechanism). However, it is clear that the engine valve is not limited to the intake valve and the number of intake valves is not limited.

The variable valve apparatus shown in FIGS. 1 to 3 has a pair of intake valves 12 and 12 slidably provided on a cylinder head 11 via a valve guide (not shown), A hollow camshaft 13 rotatably supported by a cam bearing 14, and two eccentric cams 15, 15 which are rotary cams fixed to the camshaft 13 by press fitting or the like.
A control shaft 16 rotatably supported by the same cam bearing 14 above the cam shaft 13, and a pair of rocker arms 18, 18 rotatably supported by the control shaft 16 via a control cam 17. A pair of independent swing cams 20 and 20 disposed at the upper ends of the intake valves 12 and 12 via valve lifters 19 and 19;
And valve springs 33 for biasing the valve spring in the valve closing direction.

The eccentric cams 15, 15 and the rocker arms 18, 18 are linked by link arms 25, 25, while the rocker arms 18, 18 and the swing cam 2 are linked.
0 and 20 are linked by link members 26 and 26. The camshaft 13 is disposed along the engine front-rear direction (cylinder row direction), and also via a driven sprocket (not shown) provided at one end or a timing chain wound around the driven sprocket. Torque is transmitted from the crankshaft of the engine.

The cam bearing 14 is mounted on the cylinder head 11.
A main bracket 14a provided at an upper end portion of the main bracket 14 and supporting an upper portion of the camshaft 13, and a sub-bracket 14b provided at an upper end portion of the main bracket 14a and rotatably supporting the control shaft 16; 14a, 14
b is fixed together from above by a pair of bolts 14c, 14c.

As shown in FIG. 4, the two eccentric cams 15 have a substantially ring shape and have a small-diameter cam body 15a and a flange 1 provided integrally on the outer end surface of the cam body 15a.
5b, the cam shaft insertion hole 15c is formed in the inner axial direction, and the axis X of the cam body 15a is eccentric by a predetermined amount in the radial direction from the axis Y of the cam shaft 13.

Each of the eccentric cams 15 has a camshaft 13
, Are press-fitted and fixed via cam shaft insertion holes 15c on both outer sides not interfering with the valve lifters 19, 19, and the outer peripheral surfaces 15 of both cam bodies 15a, 15a.
d and 15d are formed in the same cam profile.

As shown in FIG. 3, each of the rocker arms 18 is bent substantially in a crank shape when viewed from a plane, and a base 18a at the center is rotatably supported by the control cam 17. A pin hole 18d into which the pin 21 connected to the distal end of the link arm 25 is press-fitted is formed through one end 18b protruding from each outer end of each base 18a, while each cylindrical shape is formed. A pin hole 18e into which a pin 28 connected to one end 26a of each link member 26 described later is press-fitted is inserted into the other end 18c protruding from each inner end of the base 18a.
Are formed.

Each of the control cams 17 has a cylindrical shape and is fixed to the outer periphery of the control shaft 16, and the position of the axis P1 is eccentric from the axis P2 of the control shaft 16 by α as shown in FIG. I have.

The swing cam 20 is shown in FIGS.
As shown in the figure, the base end portion 2 has a substantially horizontal U-shape and has a substantially annular shape.
2 has a support hole 22a through which the camshaft 13 is inserted and rotatably supported.
8 is provided with a pin hole 23a at the end 23 located on the other end 18c side.
Are formed through.

The lower end of the oscillating cam 20 has a base end 2.
A base circular surface 24a on the two sides and a cam surface 24b extending in an arc shape from the base circular surface 24a toward the end edge of the end portion 23 are formed.
The base circular surface 24a and the cam surface 24b abut on a predetermined position on the upper surface of each valve lifter 19 according to the swing position of the swing cam 20.

That is, in view of the valve lift characteristics shown in FIG. 5, a predetermined angle range θ1 of the base circular surface 24a is a base circle section as shown in FIG. 1, and a predetermined angle range from the base circle section θ1 of the cam surface 24b. The range θ2 is set to be a so-called ramp section, and the predetermined angle range θ3 from the ramp section θ2 of the cam surface 24b is set to be a lift section.

The link arm 25 has a relatively large annular base 25a and a protruding end 25b projecting from a predetermined position on the outer peripheral surface of the base 25a. The eccentric cam 15 has a cam hole 15c rotatably fitted on the outer peripheral surface of the cam main body 15a, while a protruding end 25b has a pin hole 25d through which the pin 21 is rotatably inserted. Is formed. Note that the link arm 25 and the eccentric cam 15 constitute a swing drive unit.

Further, as shown in FIG. 1, the link member 26 is formed in a linear shape having a predetermined length, and circular end portions 26a and 26b have the other end 1 of the rocker arm 18 attached thereto.
8c and each pin hole 18d, 23 of the end 23 of the swing cam 20.
Pin insertion holes 26c and 26d through which the ends of the pins 28 and 29 press-fitted into a are rotatably inserted are formed.
At one end of each of the pins 21, 28, 29, snap rings 30, 31, 32 for regulating the axial movement of the link arm 25 and the link member 26 are provided.

The control shaft 16 is rotatably driven within a predetermined rotation angle range by a DC servo motor 101 constituting an electromagnetic actuator provided at one end, and as shown in FIG. Servo motor 10
Reference numeral 1 is controlled by a drive current from a control device CPU as a control shaft operating angle control means. The control device CPU includes an engine (engine) speed sensor 103 for detecting an engine (engine) speed, and an engine (engine) load sensor 10 for detecting a load on the engine (engine).
4 to detect a current engine operating state based on detection signals from various sensors, determine a target valve characteristic according to the detected engine operating state, and determine an angle corresponding to the target valve characteristic. In order to drive the control shaft 16 to the position, a drive signal (drive current) is output to the DC servomotor 101 based on the control shaft actual operating angle detected by the operating angle sensor 102. The configuration of the control device CPU will be described later.

In the following, the operation of the variable valve operating device will be described. First, when the engine is running at a low speed and low load, the DC servo motor 1 is controlled by a control signal (drive current) from the control unit CPU.
01 is rotationally driven to one side. Therefore, the control cam 17
6A and 6B, the axis P1 is held at the upper left rotation position from the axis P2 of the control shaft 16, and the thick portion 17a
Moves upward from the camshaft 13. As a result, the entire rocker arm 18 moves upward with respect to the cam shaft 13, whereby each swing cam 20 is connected to the link member 2.
6, the end 23 is forcibly pulled up slightly and the whole is turned to the left.

Therefore, as shown in FIGS. 6A and 6B, when the eccentric cam 15 rotates and pushes up one end 18 b of the rocker arm 18 via the link arm 25, the lift amount of the rocker cam 20 is increased via the link member 26. The lift amount L1 is relatively small as shown in FIG. 6B.

Therefore, in such a low speed and low load range, the valve lift becomes small as shown by the broken line in FIG.
The opening timing of each intake valve 12 is delayed (operating angle is reduced), and the valve overlap with the exhaust valve is reduced. For this reason, improvement in fuel consumption and stable rotation of the engine can be obtained.

On the other hand, when the engine shifts at the time of high speed and high load of the engine, the DC servomotor 101 is rotationally driven in the opposite direction by the control signal from the control device CPU. Accordingly, as shown in FIGS. 7A and 7B, the control shaft 16 rotates the control cam 17 clockwise from the position shown in FIG. 6, and moves the shaft center P1 (thick portion 17a) downward. Therefore, the rocker arm 18 moves in the direction of the camshaft 13 (downward) as a whole, and the other end portion 18c pushes the upper end portion 23 of the swing cam 20 downward via the link member 26, thereby causing the rocker arm 18 to move downward. Swing cam 20
The whole is rotated clockwise by a predetermined amount.

Accordingly, the valve lifter 1 of the swing cam 20
The contact position of the lower surface with respect to the upper surface 9 moves to the left position as shown in FIGS. 7A and 7B. For this reason, the eccentric cam 15 rotates as shown in FIG.
When b is pushed up via the link arm 25, the lift amount L2 with respect to the valve lifter 19 increases as shown in FIG. 7B.

Therefore, in such a high-speed, high-load region, the cam lift characteristics are larger than those in the low-speed, low-load region, and the valve lift (operating angle) is increased as shown by the solid line in FIG. The opening timing is earlier and the closing timing is later. As a result, the intake charging efficiency is improved, and a sufficient output can be secured.

By the way, in the above variable valve device,
The control shaft 16 is driven to an angular position corresponding to the target valve characteristic to control the actual valve characteristic to the target valve characteristic.
If there is a variation in the relationship between the angle position and the valve characteristics,
The actual valve characteristics cannot be accurately controlled to the target valve characteristics.

Therefore, as shown as a conventional example, FIG.
As shown in the system diagram of FIG. 0 and the block diagram of FIG. 11, the operating angle (rotational position) of the control shaft 3 for changing the swing fulcrum is detected by an operating angle sensor such as a potentiometer. Based on the operating angle signal, the position servo controller (linear controller) provided in the control device compares the operating angle as a detection result with the target control shaft operating angle, and sets the operating angle (rotational position) of the control shaft 3 to the target. The drive control signal for the DC servomotor is feedback-controlled based on the operating angle so that the target control shaft operating angle (rotational position) corresponding to the valve characteristic of (1) is obtained. Note that a reduction gear is interposed between the DC servo motor and the control shaft 3.

However, in the variable valve system, FIG.
As shown in FIG.
As shown in the VEL mechanism block diagram of FIG. 12, the reaction force torque generated by the reaction force of each of the valve springs 33, 33 and the combustion pressure, etc., is linked to 0, 20 by the link members 26, 26. The torque generated by the DC servomotor 101 is transmitted to the control shaft 16 of the mechanical mechanism via the valve lifter 19, the swing cams 20, 20, the link members 26, 26, and the rocker arm 18.

In the feedback control of the operating angle of the control shaft, since the control based on the operating angle has a large control delay, during the fixed position control in which the operating angle is maintained at the predetermined angle position, the control shown in FIG. As shown in the figure, a control deviation based on the reaction torque is generated.
When the engine speed is high, a control deviation based on the reaction torque appears remarkably, which impairs the control accuracy of the variable valve device, and provides a sufficient effect of improving the engine output and reducing the fuel consumption. Disappears.

Therefore, in the variable valve apparatus according to Embodiment 1 of the present invention, the DC servo motor 10 in the VEL mechanism is used.
As a content of the control device CPU for outputting the motor drive signal to 1, the current control amount necessary for matching the target control axis operation angle and the control axis actual operation angle is corrected by the current value corresponding to the reaction torque. The control will be described below with reference to the system block diagram of FIG.

That is, the control unit CPU detects an engine speed based on a signal from the engine speed sensor 103 and an engine speed detecting means B1 for detecting the engine speed based on a signal from the engine load sensor 104. Engine load detecting means B2; target operating angle calculating means B3 for determining a target control shaft operating angle from the engine speed detected by the engine speed detecting means B1 and the engine load detected by the engine load detecting means B2; Operating angle detecting means B4 for detecting an actual operating angle of the control shaft 16 based on a signal from the operating angle sensor 102;
The target control shaft operating angle calculated in step 3 and the operating angle detecting means B4
A current control amount calculating means B5 for calculating a current control amount necessary to make the actual control shaft actual operating angle detected by the control shaft coincide with the control shaft actual operating angle; Cam angle calculation means B for calculating the cam angle
6, a reaction torque equivalent current calculation means B7 for calculating a reaction torque equivalent current acting on the control shaft 16 from the engine side from the cam angle of the cam shaft calculated by the cam angle calculation means B6, and a reaction torque equivalent current PWM output setting means B8 for setting and outputting a drive current for the DC servo motor 101 based on the reaction torque equivalent current calculated by the calculation means B7 and the current control amount calculated by the current control amount calculation means B5. .

More specifically, the method of calculating the reaction torque equivalent current value in the reaction torque equivalent current calculation means B7 is as shown in FIG.
Is calculated in advance, the calculated value of the reaction torque corresponding to the cam angle is calculated in advance by the current calculation means B7.
Thus, the reaction torque at that time can be immediately found from the detected cam angle of the camshaft 13,
A corresponding reaction torque equivalent current can be output. An example of a method of converting the reaction torque into a current corresponding to the reaction torque will be described below. Reaction torque equivalent current = reaction torque / gear ratio / motor torque constant × gear efficiency That is, by setting “gear ratio / motor torque constant × gear efficiency” as a fixed value, the reaction torque is converted to the reaction torque. Equivalent current is easily obtained.

FIG. 14 shows measured values of the reaction torque with respect to the cam angle of the camshaft 13 (note that # 1 to # 4 indicate the reaction torque for each cylinder in a four-cylinder engine). Numeral 15 is a calculated value of the reaction force torque with respect to the cam angle of the camshaft 13, and as is apparent from both figures,
Since there is no large difference between the calculated values, the value used for calculating the reaction torque equivalent current is a representative value of the actual measured value of the reaction torque for each cylinder (the value of the reaction torque is slightly different for each cylinder. , A representative value thereof) or a calculated value.

As described above, in the variable valve apparatus for an internal combustion engine according to the first embodiment of the present invention, the DC
The content of the control device CPU that outputs a motor drive signal to the servo motor 101 is such that the current control amount required to match the target control axis operation angle with the actual control axis operation angle is corrected by the current value corresponding to the reaction torque. As shown in FIG.
As shown in the figure, during fixed position control of the control shaft operating angle,
An operating angle generated based on a reaction torque (variable for each engine speed and operating angle), which is a non-linear characteristic due to a valve spring reaction force transmitted from the engine to the control shaft 16 through the swing cam 20 and the rocker arm 18. Fluctuations can be suppressed, whereby the control accuracy is prevented from lowering, and the effect of improving the engine output and reducing the fuel consumption can be obtained.

(Embodiment 2) Next, a variable valve apparatus for an internal combustion engine according to Embodiment 2 of the invention will be described.
The variable valve gear for an internal combustion engine according to the second embodiment of the present invention is different from the first embodiment in that the content of the control device CPU is only partially different (added). In the drawings, the same components as those in the first embodiment of the present invention are omitted from the drawings and description, or the same reference numerals are given and the description is omitted.

As shown in the system block diagram of FIG. 16, the variable valve operating apparatus for an internal combustion engine according to the second embodiment of the present invention uses the cam angle of the cam shaft 13 calculated by the cam angle calculating means B6 to obtain the current intake air. A cylinder-reaction-force-torque-coefficient calculating means for determining a cylinder in which the valve is open and calculating a reaction-force torque coefficient for each of the cylinders;
8, a current value obtained by multiplying the reaction torque coefficient of the open cylinder determined by the cylinder-specific reaction torque coefficient calculating means B9 by the reaction torque equivalent current calculated by the reaction torque equivalent current calculating means B7; This embodiment is different from the first embodiment in that the drive current for the DC servomotor 101 is set and output based on the current control amount calculated by the current control amount calculation means B5. is there.

That is, as shown by the measured value in FIG. 14 and the calculated value in FIG. 15, the reaction torque transmitted as disturbance to the control shaft 16 has a slight error (deviation) for each cylinder between the measured value and the calculated value. ), The reaction torque coefficient calculated for each cylinder by the cylinder-specific reaction torque coefficient calculating means B9 is corrected by the reaction force torque equivalent current calculating means B7 to correct the deviation. By multiplying the current corresponding to the force torque, the error (deviation) of the current corresponding to the reaction torque for each cylinder can be individually corrected.

Therefore, in the variable valve apparatus for an internal combustion engine according to the second embodiment of the present invention, in addition to the effects of the first embodiment, the reaction torque differs between the cylinders of the engine. Is absorbed, and the effect of more stably suppressing the fluctuation of the operating angle can be obtained.

Although the embodiment of the present invention has been described above, the specific configuration is not limited to the embodiment of the present invention, and there are design changes and the like without departing from the gist of the present invention. This is also included in the present invention.

For example, in the embodiment of the present invention, an intake valve is taken as an example of an engine valve, but the invention can also be applied to an exhaust valve. Further, the variable valve mechanism to which the present invention is applied is not limited to the structure illustrated in the embodiment of the present invention, but may be the structure illustrated in the conventional example or other variable valve mechanisms. The present invention can be applied to all mechanisms.

[0053]

As described above in detail, in the variable valve operating apparatus for an internal combustion engine according to the first aspect of the present invention, the target control shaft operating angle according to the operating state of the engine is calculated as described above. A target operating angle calculating means, and calculating a current control amount required for matching the target control axis operating angle calculated by the target operating angle calculating means with the actual control axis operating angle detected by the operating angle detecting means. Current control amount calculating means, cam angle calculating means for calculating the cam angle of the camshaft from the engine speed detected by the engine speed detecting means, and a camshaft cam angle calculated by the cam angle calculating means. A reaction torque equivalent current calculating means for calculating a reaction torque equivalent current acting on the control shaft from the engine; and a reaction torque equivalent current calculated by the reaction torque equivalent current calculating means and the current control amount calculating means. Based on the calculated current control amount, And output setting means for setting and outputting a drive current to the actuator, which is caused by a valve spring reaction force transmitted to the control shaft through a cam, a rocker arm, or the like during the fixed position control of the control shaft operating angle. It is possible to suppress the operating angle fluctuation generated based on the non-linear characteristic reaction torque (variable for each engine speed and operating angle), thereby preventing the control accuracy from lowering and sufficiently improving the engine output. In addition, an effect of reducing fuel consumption can be obtained.

According to a third aspect of the present invention, the cylinder in which the engine valve is currently open is determined based on the cam angle of the camshaft calculated by the cam angle calculating means. Cylinder-specific reaction torque coefficient calculating means for calculating a force torque coefficient, wherein the output setting means calculates the reaction torque coefficient of the open operating cylinder determined by the cylinder-specific reaction torque coefficient calculating means as the reaction torque. The drive current for the electromagnetic actuator is set and output based on the current value multiplied by the reaction torque equivalent current calculated by the current calculation means and the current control amount calculated by the current control amount calculation means. In addition, the control deviation between the cylinders due to the reaction torque differing between the cylinders of the engine is absorbed, and the additional effect that the operating angle fluctuation is more stably suppressed is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (a cross-sectional view taken along the line AA in FIG. 2) illustrating a variable valve apparatus during an internal combustion period according to an embodiment of the present invention.

FIG. 2 is a side view of the variable valve device.

FIG. 3 is a plan view of the variable valve device.

FIG. 4 is a perspective view showing an eccentric cam used in the variable valve device.

FIG. 5 is a valve lift characteristic diagram corresponding to a base end surface and a cam surface of an oscillating cam in the variable valve operating device.

FIG. 6 is a cross-sectional view (cross-sectional view taken along the line BB in FIG. 2) showing the operation of the variable valve device at low speed and low load.

FIG. 7 is a cross-sectional view (a cross-sectional view taken along the line BB of FIG. 2) illustrating an operation of the variable valve device at the time of high speed and high load.

FIG. 8 is a characteristic diagram of valve timing and valve lift of the variable valve operating device.

FIG. 9 is a block diagram showing an operating angle control system of the variable valve operating device.

FIG. 10 is a system diagram showing the contents of an operation angle control circuit of a conventional variable valve apparatus.

FIG. 11 is a block diagram showing the contents of an operation angle control circuit of a conventional variable valve apparatus.

FIG. 12 is a time chart showing a control shaft operating angle variation in the variable valve operating device.

FIG. 13 is a system block diagram of the variable valve operating device.

FIG. 14 is a view showing actual measurement values of reaction torque with respect to a cam angle of a cam shaft in the variable valve operating device.

FIG. 15 is a view showing a calculated value of a reaction force torque with respect to a cam angle of a cam shaft in the variable valve operating device.

FIG. 16 is a system block diagram of the variable valve device of the internal combustion engine according to the second embodiment of the present invention.

FIG. 17 is a cross-sectional view showing a conventional variable valve apparatus.

FIG. 18 is a block diagram showing an operating angle control system of a conventional variable valve device.

[Description of Signs] 12 Intake valve (engine valve) 13 Cam shaft 15 Eccentric cam (oscillation driving means) 16 Control shaft 17 Control cam 18 Rocker arm 20 Oscillating cam 25 Link arm (oscillation driving means) 33 Valve spring CPU control Device (control shaft operating angle control means) 101 DC servo motor (electromagnetic actuator) 102 Operating angle sensor (operating angle detecting means) 103 Engine speed sensor (engine speed detecting means) 104 Engine load sensor (engine load detecting means) B1 Engine speed detecting means (engine speed detecting means) B2 Engine negative detecting means (engine load detecting means) B3 Target operating angle calculating means B4 Operating angle detecting means B5 Current control amount calculating means B6 Cam angle calculating means B7 Equivalent to reaction torque Current calculation means B8 Output setting means (PWM output setting means) B9 Cylinder reaction force Torque coefficient calculation means

Claims (3)

[Claims] A control shaft disposed substantially parallel to a cam shaft; a control cam eccentrically fixed to an outer periphery of the control shaft; a rocker arm pivotally supported by the control cam; Rocking drive means for rocking one end of the rocker arm in response to rotation of a camshaft; rocking cam for linking with the other end of the rocker arm and rocking to open an engine valve; A valve spring for urging the valve in a direction to close the valve, operating angle detecting means for detecting an operating angle of the control shaft, an electromagnetic actuator for rotating the control shaft to a target control shaft operating angle, and detecting an engine speed. Means for detecting an engine speed, a target operating angle calculating means for calculating a target control shaft operating angle according to an operating state of the engine, a target control shaft operating angle calculated by the target operating angle calculating means, and detecting the operating angle. Actual control axis detected by means Current control amount calculating means for calculating a current control amount necessary for matching a dynamic angle; and cam angle calculation for calculating a cam angle of the cam shaft from an engine speed detected by the engine speed detecting means. Means, a reaction torque equivalent current calculation means for calculating a reaction torque equivalent current acting on the control shaft from the engine side from the cam angle of the cam shaft calculated by the cam angle calculation means, and a reaction torque equivalent current calculation Output setting means for setting and outputting a driving current for the electromagnetic actuator based on the reaction torque equivalent current calculated by the means and the current control amount calculated by the current control amount calculating means. Variable valve gear for internal combustion engines. 2. An engine load detecting means for detecting a load of an engine, wherein the target operating angle calculating means detects an engine speed detected by the engine speed detecting means and an engine speed detected by the engine load detecting means. The variable valve train for an internal combustion engine according to claim 1, wherein the variable valve train of the internal combustion engine is configured to calculate a target control shaft operating angle according to an operation state of the engine from the load of the engine. 3. A cylinder-specific reaction torque coefficient for determining a cylinder in which an engine valve is currently open from the cam angle of the cam shaft calculated by the cam angle calculation means and calculating a reaction torque coefficient for each cylinder. The output setting means calculates the reaction torque coefficient of the open cylinder determined by the cylinder-specific reaction torque coefficient calculation means by the reaction torque equivalent current calculated by the reaction torque equivalent current calculation means. 3. The apparatus according to claim 1, wherein a drive current for the electromagnetic actuator is set and output based on a current value multiplied by a current control amount calculated by the current control amount calculation unit. 4. Variable valve gear for internal combustion engines.