JP2001254639A - Valve characteristic control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more favourably carry out lift quantity holding control through a valve lift quantity variable mechanism constituted by having a three- dimensional cam. SOLUTION: Valve lift quantity in a driving state of an engine 11 is computed as a target value VLA by an electronic control unit(ECU) 130. A valve characteristic of a suction valve 20 is detected as a detected value VLR by detecting displacement quantity of a camshaft 22. A controlled variable of valve lift quantity variable mechanisms 22a, 36 is computed as a driving duty ratio DVL in accordance with a detected value VLA and a target value VLR by an ECU 130, and valve lift quantity variable mechanisms 22a, 36 are controlled by the driving duty ratio DVL. Even when variation of the detected value VLR becomes zero, in the case when a difference exists between the detected value VLR and the target value VLA, the driving duty ratio DVL at the time is learned and renewed as a holding command value KVL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve characteristic control device for an internal combustion engine, and more particularly to a valve characteristic control device for an internal combustion engine provided with a variable valve lift mechanism having a three-dimensional cam.

[0002]

2. Description of the Related Art In order to suitably maintain the engine characteristics even under different operating conditions of an internal combustion engine, the valve characteristics such as the valve timing and valve lift of an engine valve are varied according to the operating state of the engine. Has been conventionally known.

In recent years, as a mechanism for varying the valve lift, a camshaft is designed to be displaceable in the axial direction, and the cam ridge of the cam provided on the camshaft is moved from one end in the axial direction to the other end. A device using a so-called three-dimensional cam formed so as to change continuously has also been proposed. According to such a variable valve lift mechanism using a three-dimensional cam, the valve lift amount can be reduced by displacing the camshaft in the axial direction by, for example, a hydraulically driven actuator in accordance with the operating state of the engine. It can be changed continuously.

On the other hand, as a device for controlling a variable valve lift mechanism configured with such a three-dimensional cam,
For example, an apparatus described in JP-A-11-72031 is known. In this device, two types of detected portions are provided for a camshaft of an intake system, a reference detected portion extending linearly in the axial direction and a moving amount detected portion spirally extending coaxially. In addition to providing each, an electromagnetic pickup that generates a pulse corresponding to the passage of each of the above-mentioned detected parts accompanying the rotation of the same camshaft is provided in the vicinity thereof, so that the valve lift amount variably controlled is monitored. I have.

That is, in this case, when the camshaft moves in the axial direction, the camshaft moves in response to the passage of the reference amount to be detected and the pulse generated from the electromagnetic pickup corresponds to the passage of the movement amount to the detected portion. Then, the generation timing of the pulse generated from the electromagnetic pickup changes. Therefore, by monitoring the change of the occurrence timing, the displacement position of the camshaft in the axial direction, that is, the valve lift amount can be accurately detected. In this apparatus, the displacement position of the camshaft is feedback-controlled so that the detected valve lift amount converges to a target value for the valve lift amount calculated according to the engine operating state.

[0006]

As described above, according to the above apparatus, while the valve lift is accurately monitored and detected, the feedback control of the valve lift variable mechanism based on the detected value is performed. Done.

By the way, after the detected valve lift reaches the target value, in order to maintain the lift, a holding control for holding the displacement position of the camshaft is performed. However, in the conventional device in which the camshaft is displaced in the axial direction by a hydraulically driven actuator, the following problems in the holding control cannot be ignored.

That is, normally, the output characteristics of the hydraulic control valve and the like constituting the hydraulically driven actuator include a tolerance and a change with time. Further, the output characteristics vary depending on the engine operating state. That is, the hydraulic pressure obtained by the pump varies depending on the rotational speed of the engine and the warm-up state, and the difference in hydraulic pressure changes the output characteristics of each member of the actuator. For this reason, even if the holding control is performed in such a situation, the control command value for the hydraulic control valve and its actual output characteristic do not always correspond exactly, and in some cases, the holding position This may cause a shift or control hunting or the like associated with the feedback control.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to more suitably perform lift amount holding control through a variable valve lift amount mechanism having a three-dimensional cam. An object of the present invention is to provide a valve characteristic control device for an internal combustion engine.

It is another object of the present invention to provide a valve characteristic control device for an internal combustion engine which is capable of adapting learning control to the holding control in a very desirable manner.

[0011]

The means for achieving the above object and the effects thereof will be described below. The invention according to claim 1 has a camshaft provided with a three-dimensional cam whose cam profile continuously changes in the camshaft direction, and the camshaft in the camshaft direction of the camshaft based on hydraulic pressure supply from hydraulic pressure supply means. A valve lift variable mechanism for varying the valve lift of the engine valve according to the displacement position of
A target value calculating means for calculating a target value of the valve lift amount according to an operating state of the engine; a detecting means for detecting the valve lift amount; and a detection value detected by the detecting means being calculated by the target value calculating means. Holding control means for controlling the hydraulic pressure supply by the hydraulic pressure supply means so as to hold the valve lift amount near the calculated target value; and And learning control means for comparing the target value at that time with a control command value of the holding control means and performing learning control for correcting the control command value based on the evaluation. Make a summary.

According to the above configuration, the control command value for the holding control means, that is, the holding command value is learned and updated based on the evaluation, so that the output characteristics of the hydraulic pressure supply system have tolerances, changes over time, and the like. , It is possible to always obtain an appropriate value as the holding command value. In addition, by constantly learning and updating to the appropriate holding command value, it is possible to promptly shift to the holding control.

According to a second aspect of the present invention, in the first aspect of the present invention, the learning control means controls the valve lift variable mechanism in a direction in which the valve lift becomes relatively small. The gist of the present invention is to provide an initial value storage means for storing a value as the learning initial value.

[0014] The result of the holding control becomes poor and the valve lift temporarily becomes excessive until the learning started first is completed once or until the learning is completed once after recovery from the failure. There is. And in that case,
Temporarily unstable combustion of the air-fuel mixture in the combustion chamber,
Misfires and engine stalls may occur.

In this respect, according to the above configuration, a command value for controlling the valve lift variable mechanism such that the valve lift is relatively small is stored in the initial value storage means as the learning initial value of the holding command value. This ensures that this problem can be avoided.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a learning value update that permits the learning control means to update the learning value only when the temperature of the engine is equal to or higher than a predetermined temperature. The gist of the present invention is to further include permission means.

The actual holding command value for the engine temperature (for example, oil temperature or water temperature) tends to be high on the low temperature side and high temperature side, and low on the intermediate temperature range. In this regard, according to the above configuration, since the learning update of the holding command value by the learning control is permitted only when the engine temperature of the engine is equal to or higher than the predetermined temperature, the learning update is performed only at the predetermined temperature or higher, that is, only at the high temperature side. Is allowed to be close to the actual holding command value even on the low temperature side. Therefore, the hold command value used at the next start or at the time of cold is also an appropriate value.

According to a fourth aspect of the present invention, in the first aspect of the invention, when the calculated target value of the valve lift amount is close to the variable limit of the variable valve lift amount mechanism, The gist of the present invention is to further include a prohibition unit that prohibits the learning control unit from updating the learning value.

In the vicinity of the variable limit of the variable valve lift mechanism, the mechanism may be temporarily stopped due to mechanical restrictions. In addition, since there is an individual difference in each of the variable valve lift mechanisms, the control range of the variable valve lift may vary. Therefore, in the vicinity of the variable limit, an inappropriate holding command value may be learned by the learning control unit.

In this respect, according to the above configuration, the above-described problem can be avoided by providing the prohibition means for prohibiting the update of the learning value by the learning control means near the variable limit of the variable valve lift mechanism. Become like

According to a fifth aspect of the present invention, in the first aspect of the invention, when the calculated target value of the valve lift amount is close to the variable limit of the valve lift variable mechanism, The gist of the present invention is to further include a limiter for limiting the update of the learning value by the learning controller.

As described above, there is a possibility that the learning by the learning control means may not be appropriate in the vicinity of the variable limit of the variable valve lift mechanism. In the above, the provision of the restriction means for restricting the update of the learning value by the learning control means makes it possible to perform the learning control while avoiding such a problem.

According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the learning control means is provided for each of the engine in a different temperature range between a cold range and a warm range. The learning values are separately updated, and for the intermediate temperature range, the interpolation of those learning values is the gist.

When a hydraulically driven actuator is used to operate the variable lift amount actuator, the holding command value also differs depending on the temperature of the engine, for example, because the viscosity coefficient changes depending on the temperature of the hydraulic oil. Become.

In this respect, according to the above configuration, the correction of the holding command value by the learning control means is performed separately for the cold region of the engine and the warm region of the engine, so that The valve lift amount can be suitably controlled between the region and the warm region. Further, by calculating a value obtained by interpolating the holding command values in the two regions as a holding command value in an intermediate region between the cold region and the warm region, the valve lift amount control is also performed in the intermediate region. It can be suitably performed.

According to a seventh aspect of the present invention, there is provided a camshaft provided with a three-dimensional cam whose cam profile changes continuously in the camshaft direction, wherein the camshaft is provided based on a hydraulic pressure supply from a first hydraulic pressure supply means. A valve lift variable mechanism for varying a valve lift of an engine valve in accordance with a displacement position of the shaft in a cam axis direction; and a cam lift and an engine output shaft based on a hydraulic pressure supply from a second hydraulic pressure supply means. A valve timing variable mechanism that varies a valve timing of the engine valve in accordance with a change in a relative rotation phase, a first target value calculation unit that calculates a target value of the valve lift amount in accordance with an operating state of the engine, First detection means for detecting the valve lift amount, and a first detection value detected by the first detection means being near a target value calculated by the target value calculation means. A first holding control means for controlling the hydraulic pressure supply by the hydraulic pressure supply means so as to maintain the valve lift amount when the first detected value is maintained, And the control command value of the first holding control means is compared with the target value at that time,
First learning control means for performing learning control for correcting the control command value based on the evaluation, and second target value calculation means for calculating a target value of the valve timing according to an operating state of the engine; And a second detecting the valve timing.
And the valve timing when the second detection value detected by the second detection means is close to the target value calculated by the second target value calculation means is held. A second holding control unit for controlling a hydraulic pressure supply by a hydraulic pressure supply unit, and comparing the second detection value with a target value at the time when the second detection value is continued in a certain state. A second learning control unit that evaluates a control command value of the holding control unit and performs learning control for correcting the control command value based on the evaluation. The gist is that the variable valve timing mechanism is fixedly controlled, and the variable valve timing variable mechanism is fixedly controlled during learning control of the variable valve timing mechanism.

Normally, according to the variable valve operating mechanism, the variable valve operating mechanism using the three-dimensional cam described in claim 1 is combined with the variable valve timing mechanism for changing the valve timing in the above configuration. When used, it may be difficult to accurately perform the learning control of the holding command value.

In this regard, according to the above configuration, when performing the learning control of the holding command values of the two mechanisms, the mechanism on the side not to be subjected to the learning control is forcibly fixedly controlled, so that each of these mechanisms is controlled. The learning control of the holding command value can be accurately performed.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the fixed control of the variable valve timing mechanism during the learning control of the variable valve lift mechanism is performed by:
The control is performed on the most retarded side of the valve timing, and the fixed control of the variable valve lift mechanism during the learning control of the variable valve timing mechanism is performed on the minimum lift side of the valve lift. This is the gist.

According to the above arrangement, the valve timing is fixed at the most retarded side during the learning control of the variable valve lift mechanism, and the valve lift is fixed at the minimum lift side during the learning control of the variable valve timing mechanism. By performing the control, it is possible to preferably prevent the valve overlap amount from becoming excessive during the learning control.

According to a ninth aspect of the present invention, there is provided a camshaft provided with a three-dimensional cam whose cam profile continuously changes in the cam axis direction, wherein the cam is based on the hydraulic pressure supplied from the first hydraulic pressure supply means. A valve lift variable mechanism for varying a valve lift of an engine valve in accordance with a displacement position of the shaft in a cam axis direction; and a cam lift and an engine output shaft based on a hydraulic pressure supply from a second hydraulic pressure supply means. A valve timing variable mechanism that varies a valve timing of the engine valve in accordance with a change in a relative rotation phase, a first target value calculation unit that calculates a target value of the valve lift amount in accordance with an operating state of the engine, First detection means for detecting the valve lift amount, and a first detection value detected by the first detection means being near a target value calculated by the target value calculation means. A first holding control means for controlling the hydraulic pressure supply by the hydraulic pressure supply means so as to maintain the valve lift amount when the first detected value is maintained, And the control command value of the first holding control means is compared with the target value at that time,
First learning control means for performing learning control for correcting the control command value based on the evaluation, and second target value calculation means for calculating a target value of the valve timing according to an operating state of the engine; And a second detecting the valve timing.
And the valve timing when the second detection value detected by the second detection means is close to the target value calculated by the second target value calculation means is held. A second holding control unit for controlling a hydraulic pressure supply by a hydraulic pressure supply unit, and comparing the second detection value with a target value at the time when the second detection value is continued in a certain state. A second learning control unit that evaluates a control command value of the holding control unit and performs learning control for correcting the control command value based on the evaluation;
The gist is that the learning control by the second learning control means is performed on condition that the learning control by the learning control means is normally performed.

According to the above configuration, the learning control of the variable valve lift mechanism is executed with priority, so that the holding control through the variable valve lift mechanism can be stabilized early.

[0033]

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

FIG. 1 shows an in-line four-cylinder in-vehicle gasoline engine (hereinafter simply referred to as "engine") as an internal combustion engine.
11 is shown. The engine 11 includes a cylinder block 13 provided with a reciprocating piston 12 and an oil pan 13 a provided below the cylinder block 13.
And a cylinder head 14 provided above the cylinder block 13.

A crankshaft 15 serving as an output shaft is rotatably supported below the engine 11, and the crankshaft 15 is connected to a piston 1 via a connecting rod 16.
2 are connected. The reciprocating movement of the piston 12 is converted into rotation of the crankshaft 15 by the connecting rod 16. A combustion chamber 17 is provided above the piston 12.
Are connected to an intake passage 18 and an exhaust passage 19. The intake passage 18 and the combustion chamber 17 are communicated and blocked by an intake valve 20, and the exhaust passage 19 and the combustion chamber 17
Are communicated and shut off by the exhaust valve 21.

On the other hand, the cylinder head 14 is provided with an intake side camshaft 22 and an exhaust side camshaft 23 in parallel. The intake-side camshaft 22 is supported on the cylinder head 14 so as to be rotatable and movable in the axial direction, and the exhaust-side camshaft 23 is supported on the cylinder head 14 so as to be rotatable but not movable in the axial direction. Have been.

A variable valve timing actuator 24 having a timing pulley 24a is provided at one end of the intake side camshaft 22, and a variable lift amount for moving the intake side camshaft 22 in the axial direction is provided at the other end. An actuator 22a is provided. A timing pulley 25 is attached to one end of the exhaust-side camshaft 23. The timing pulley 25 and the timing pulley 24 a of the variable valve timing actuator 24 are connected via a timing belt 26 to a pulley 15 a attached to the crankshaft 15. The rotation of the crankshaft 15 as the drive-side rotation shaft is transmitted to the intake-side camshaft 22 and the exhaust-side camshaft 23 as the driven-side rotation shaft via the timing belt 26, so that the intake-side camshafts The camshaft 22 and the exhaust-side camshaft 23 rotate in synchronization with the rotation of the crankshaft 15.

The intake camshaft 22 is provided with an intake cam 27 that contacts the upper end of the intake valve 20, and the exhaust camshaft 23 is provided with an exhaust cam 28 that contacts the upper end of the exhaust valve 21. . When the intake camshaft 22 rotates, the intake valve 20 is opened and closed by the intake cam 27, and when the exhaust camshaft 23 rotates, the exhaust valve 21 is opened and closed by the exhaust cam 28.

Here, the cam profile of the exhaust cam 28 is constant in the axial direction of the exhaust camshaft 23, but the cam profile of the intake cam 27 is as shown in FIG. It changes continuously in the axial direction. That is, the intake cam 27 is configured as the three-dimensional cam described above.

The intake camshaft 22 is indicated by an arrow A.
Moving in the direction, the intake valve 20 by the intake cam 27
The valve lift of the intake valve 20 gradually increases, and the valve opening time of the intake valve 20 gradually increases. When the intake camshaft 22 moves in the direction opposite to the direction of the arrow A,
As the valve lift of the intake valve 20 by the intake cam 27 gradually decreases, the opening time of the intake valve 20 gradually decreases. Therefore, the intake side camshaft 2
2 in its axial direction, the intake valve 2
Adjustment of the valve opening time and the valve lift amount of 0 can be performed.

The variable valve lift mechanism according to the present embodiment includes the above-described variable lift actuator 22a and a first oil control valve (OCV) 36.

Next, a lift amount variable actuator 22 for moving the intake side camshaft 22 in the axial direction.
a and an oil supply structure for driving the lift variable actuator 22a by hydraulic pressure will be described with reference to FIG.

As shown in FIG. 3, the variable lift amount actuator 22a includes a cylinder tube 31 having a cylindrical shape,
A piston 32 provided in the cylinder tube 31;
It comprises a pair of end covers 33 provided so as to close the openings at both ends of the cylinder tube 31. This cylinder tube 31 is fixed to the cylinder head 14.

The piston 32 has one end cover 33
The intake-side camshaft 22 is connected via an auxiliary shaft 33a penetrating through. A rolling bearing 33b is interposed between the auxiliary shaft 33a and the intake-side camshaft 22, and the variable lift amount actuator 22a moves the rotating intake-side camshaft 22 through the auxiliary shaft 33a and the rolling bearing 33b in the rotational axis direction. It can be driven smoothly.

The cylinder 32 has a piston 32
The partition is divided into a first pressure chamber 31a and a second pressure chamber 31b. A first supply / discharge passage 34 formed in one end cover 33 is connected to the first pressure chamber 31a, and a second supply / discharge passage 35 formed in the other end cover 33 is connected to the second pressure chamber 31b. Is connected.

Then, the first pressure chamber 31a and the second pressure chamber 31 are connected via the first supply / discharge passage 34 or the second supply / discharge passage 35.
When hydraulic oil is selectively supplied to the piston 32, the piston 32
Moves in the axial direction of the intake-side camshaft 22. With the movement of the piston 32, the intake camshaft 22 also moves in the axial direction.

First supply / discharge passage 34 and second supply / discharge passage 35
Is connected to the first oil control valve 36. A supply passage 37 and a discharge passage 38 are connected to the first oil control valve 36. The supply passage 37 is connected to the oil pan 1 via an oil pump P driven by the rotation of the crankshaft 15.
3a, and the discharge passage 38 is connected to the oil pan 13
a.

The first oil control valve 36 has a casing 39, and the casing 39 has a first supply / discharge port 40, a second supply / discharge port 41, a first discharge port 42,
A second discharge port 43 and a supply port 44 are provided. The first supply / discharge port 40 has a second supply / discharge passage 3.
The first supply / discharge passage 3 is connected to the second supply / discharge port 41.
4 are connected. Further, the supply passage 37 is connected to the supply port 44, and the first discharge port 42 and the second
The discharge passage 38 is connected to the discharge port 43. In the casing 39, a spool 48 having four valve portions 45 and urged in opposite directions by a coil spring 46 and an electromagnetic solenoid 47 is provided.

When the electromagnetic solenoid 47 is in the demagnetized state, the spool 48 is moved by the elastic force of the coil spring 46 to one end of the casing 39 (the right side in FIG. 3).
And the first supply / discharge port 40 and the first discharge port 4
2 and the second supply / discharge port 41 and the supply port 44. In this state, the operating oil in the oil pan 13a is supplied to the supply passage 37, the first oil control valve 3
6 and the first pressure chamber 31a through the first supply / discharge passage 34.
Supplied to The hydraulic oil in the second pressure chamber 31b is returned to the oil pan 13a via the second supply / discharge passage 35, the first oil control valve 36, and the discharge passage 38. As a result, the piston 32 and the intake camshaft 22 move in the direction opposite to the arrow A.

On the other hand, when the electromagnetic solenoid 47 is excited, the spool 48 resists the elastic force of the coil spring 46 and the other end of the casing 39 (left side in FIG. 3).
And the second supply / discharge port 41 is connected to the second discharge port 4
3, the first supply / discharge port 40 communicates with the supply port 44. In this state, the hydraulic oil in the oil pan 13a is supplied to the second pressure chamber 31b via the supply passage 37, the first oil control valve 36, and the second supply / discharge passage 35. The hydraulic oil in the first pressure chamber 31a is supplied to the first supply / discharge passage 34, the first oil control valve 36,
The oil is returned to the oil pan 13a via the discharge passage 38. As a result, the piston 32 and the intake camshaft 22 move in the direction of arrow A.

Further, when the power supply to the electromagnetic solenoid 47 is controlled and the spool 48 is positioned in the middle of the casing 39, the first supply / discharge port 40 and the second supply / discharge port 41 are closed, and the supply / discharge port 40, Movement of hydraulic oil through 41 is prohibited. In this state, the first pressure chamber 31a
The supply and discharge of hydraulic oil to and from the second pressure chamber 31b are not performed, the hydraulic oil is filled and held in the first pressure chamber 31a and the second pressure chamber 31b, and the piston 32 and the intake camshaft 22 are fixed. You.

Next, the variable valve timing actuator 24 for adjusting the opening / closing timing of the intake valve 20 will be described in detail with reference to FIG. As shown in FIG. 4, the variable valve timing actuator 24 includes a timing pulley 24a. This timing pulley 24a is a cylindrical portion 51 through which the intake camshaft 22 penetrates.
A disk portion 52 protruding from the outer peripheral surface of the cylindrical portion 51; and a plurality of external teeth 53 provided on the outer peripheral surface of the disk portion 52. The cylindrical portion 51 of the timing pulley 24a is rotatably supported by the bearing portion 14a of the cylinder head 14. The intake-side camshaft 22 penetrates the cylindrical portion 51 so as to be able to slide and move in the axial direction.

An inner gear 54 provided so as to cover the tip of the intake camshaft 22 is fixed by bolts 55. As shown in FIG. 5, the inner gear 54 has a configuration in which a large-diameter gear portion 54a having bevel teeth and a small-diameter gear portion 54b also having bevel teeth are formed in two stages.

Further, the small-diameter gear portion 54b of the inner gear 54
In FIG. 4, a sub gear 56 having helical external teeth 56a and helical internal teeth 56b is meshed with the internal teeth 56b as shown in FIG. During this engagement,
A ring-shaped spring washer 57 is disposed between the inner gear 54 and the sub gear 56, and urges the sub gear 56 in the axial direction so as to be separated from the inner gear 54. In addition,
The outer diameters of the inner gear 54 and the sub gear 56 are the same,
The inclination of each of the bevels is an inclination that can be combined with a helical spline 61b provided at a corresponding position of the vane rotor 61 described below.

The disk portion 52 of the timing pulley 24a is provided with a plurality of bolts 58 (here, four bolts) by means of a housing 59 and a first pressure chamber 70 and a second pressure A cover 60 for sealing the chamber 71 is attached. The cover 6
At the center of 0, there is provided a hole 60a for opening a cylindrical space 61c to be described later to smoothly slide the intake-side camshaft 22 in the axial direction.

FIG. 6 shows the inside of the housing 59 by removing the bolt 58, the cover 60 and the bolt 55.
Shows the state as viewed from the left. The variable valve timing actuator 24 shown in FIG.
The cross-sectional state along line B is shown.

As shown in FIG.
Is provided with a plurality of (here, four) wall portions 62, 63, 64, 65 protruding from the inner peripheral surface 59a toward the center. A disk-shaped vane rotor 61 that is in contact with the distal end surfaces of the wall portions 62, 63, 64, and 65 at the outer peripheral surface 61a is rotatably disposed.

A cylindrical space 61c (FIG. 4) is formed at the center of the disk-shaped vane rotor 61. In the present embodiment, the shaft of the intake-side camshaft 22 is provided on the entire inner peripheral surface. A helical spline 61b having a predetermined twist angle with respect to the direction is formed. The large-diameter gear portion 54a of the inner gear 54 and the outer teeth 56a of the sub gear 56, both of which are formed with helical teeth, are meshed with the helical spline 61b. Regarding the torsion angle of the helical spline 61b, a detailed description will be given later of the angle setting mode and the operation.

On the other hand, the inner gear 56b of the sub gear 56 and the small-diameter gear 54
According to the engagement with the spring b and the action of the spring washer 57, the large-diameter gear portion 54a of the inner gear 54 and the external teeth 56a of the sub-gear 56 generate an urging force that rotates relatively in opposite directions. . For this reason, the backlash between the helical spline 61b and the gears 54 and 56 is absorbed, and the inner gear 54 can be arranged with high accuracy with respect to the vane rotor 61, and the sound of the inner gear 54 can be suppressed.

The disk-shaped vane rotor 61 projects from the outer peripheral surface 61 a into the space between the wall portions 62, 63, 64, 65, and has a distal end in contact with the inner peripheral surface 59 a of the housing 59. , 67, 68, 69. These vanes 66, 67, 68, 69 are attached to the wall 6
By partitioning the space between 2,63,64,65,
A first pressure chamber 70 and a second pressure chamber 71 are formed.

In the variable valve timing actuator 24 having the above-described structure, when the crankshaft 15 is rotated by driving the engine and the rotation is transmitted to the timing pulley 24a via the timing belt 26,
Timing pulley 24a and intake camshaft 22
Rotate together in the adjusted rotational phase difference state.
As described above, the intake valve 20 (FIG. 1) is driven to open and close as the intake camshaft 22 rotates.

When the engine 11 is driven, the vane rotor 61 is rotated relative to the housing 59 in the rotational direction by hydraulic control of the first pressure chamber 70 and the second pressure chamber 71, ie, the intake cam When the rotational phase difference adjustment control is performed on the side where the shaft 22 is advanced with respect to the crankshaft 15, the opening / closing timing of the intake valve 20 is advanced.

Conversely, when the vane rotor 61 is relatively rotated with respect to the housing 59 in a direction opposite to the rotation direction, that is, the intake camshaft 22 is rotated to the side where the intake camshaft 22 is retarded with respect to the crankshaft 15. When the phase difference adjustment control is performed, the opening / closing timing of the intake valve 20 is delayed.

The opening and closing timing of the intake valve 20 is normally delayed when the engine 11 is running at a low speed, and advanced when the engine 11 is running at a high speed. This is to stabilize the engine rotation when the engine 11 is running at a low speed and to improve the efficiency of sucking the mixed gas into the combustion chamber 17 when the engine 11 is running at a high speed.

Next, a description will be given of a structure of the variable valve timing actuator 24 for hydraulically controlling the rotational phase difference between the housing 59 and the vane rotor 61 for adjusting the opening / closing timing of the intake valve 20.

As shown in FIG. 6, advancement oil passage openings 80 are respectively opened on the first pressure chamber 70 side of the walls 62 to 65 protruding into the housing 59. 6
On the second to second pressure chamber 71 sides 2 to 65, retard oil passage openings 81 are respectively opened. Further, the oil passage opening 8 for advancement
The disk portion 52 (FIG. 4) in each of the wall portions 62 to 65 that are in contact with 0
On the side, recesses 62a to 65a are provided so that even when the vanes 66 to 69 block the advancing oil passage opening 80, the vane rotor 61 can apply hydraulic pressure to rotate in the advancing direction. I have. Similarly, in each of the wall portions 62 to 65 in contact with the retard oil passage opening portion 81, the disc portion 52 (FIG. 4) side includes:
Even when the vanes 66 to 69 block the retard oil passage opening 81, the concave portions 62b to 65b are provided so that the vane rotor 61 can apply hydraulic pressure to rotate in the retard direction.

On the other hand, as shown in FIG. 4, each advance oil passage opening 80 is provided with an advance control oil passage 84 in the disk portion 52 and an advance control oil passage 86, 88 in the cylindrical portion 51. Thereby, it is connected to one outer circumferential groove 51a of the cylindrical portion 51. In addition, each retardation oil passage opening 81 is provided with a retard control oil passage 85 in the disc portion 52,
Due to the retard angle control oil passages 87 and 89 in the cylinder 51, the cylinder 51
Is connected to the other outer peripheral groove 51b.

The lubricating oil passage 90 branched from the retard control oil passage 87 in the cylindrical portion 51 is connected to a wide inner circumferential groove 91 provided on the inner circumferential surface 51c of the cylindrical portion 51. As a result, the hydraulic oil flowing through the retard control oil passage 87 is supplied to the inner peripheral surface 51c of the cylindrical portion 51 and the outer peripheral surface 2 at the end of the intake camshaft 22.
2b as lubricating oil.

One outer peripheral groove 51a of the cylindrical portion 51 is connected to a second oil control valve 94 via an advanced angle control oil passage 92 in the cylinder head 14, and the other outer peripheral groove 51b of the cylindrical portion 51 is connected to a cylinder. A second oil control valve 94 is connected via a retard control oil passage 93 in the head 14.

A supply passage 95 and a discharge passage 96 are connected to the second oil control valve 94. The supply passage 95 is connected to the oil pan 13a via the same oil pump P used for the first oil control valve 36, and the discharge passage 96 is directly connected to the oil pan 13a. Accordingly, the oil pump P is connected to the two supply passages 3 from the oil pan 13a.
The hydraulic oil is sent to 7,95.

The second oil control valve 94 is configured similarly to the first oil control valve 36,
Casing 102, first supply / discharge port 104, second supply / discharge port 106, valve 107, first discharge port 108, second
Discharge port 110, supply port 112, coil spring 114, electromagnetic solenoid 116, and spool 11
8 is provided. The first supply / discharge port 104 is connected to a retard control oil passage 93 in the cylinder head 14, and the second supply / discharge port 106 is connected to an advance control oil passage 92 in the cylinder head 14. Also, the supply port 112
Is connected to a supply passage 95, and the first discharge port 108 and the second discharge port 110 are connected to a discharge passage 96.

Therefore, when the electromagnetic solenoid 116 is in the demagnetized state, the spool 118
14, the first supply / discharge port 104 and the first discharge port 108 communicate with each other, and the second supply / discharge port 106
Communicates with the supply port 112. In this state, the operating oil in the oil pan 13 a is supplied to the supply passage 95, the second oil control valve 94, the advance control oil passage 92, and the outer peripheral groove 5.
1a, the advance control oil passage 88, the advance control oil passage 86, the advance control oil passage 84, the advance oil passage opening 80, and the recess 62a,
It is supplied to the first pressure chamber 70 of the variable valve timing actuator 24 via 63a, 64a, 65a.
In addition, the second of the variable valve timing actuator 24
Hydraulic oil in the pressure chamber 71 is released from the recesses 62b, 63b,
64b, 65b, retard passage oil passage opening 81, retard control oil passage 85, retard control oil passage 87, retard control oil passage 89, outer peripheral groove 5
1b, the retard control oil passage 93, the second oil control valve 94, and the oil passage 13 through the discharge passage 96.
Returned to a. As a result, the vane rotor 61 relatively rotates in the advance direction with respect to the housing 59, and the opening / closing timing of the intake valve 20 is advanced as described above.

On the other hand, when the electromagnetic solenoid 116 is excited, the spool 118 is disposed on the other end side (left side in FIG. 4) of the casing 102 against the elastic force of the coil spring 114, and the second supply / discharge port 106 Communicates with the second discharge port 110, and the first supply / discharge port 104 communicates with the supply port 112. In this state, the oil pan 1
The hydraulic oil in 3a is supplied to the supply passage 95, the second oil control valve 94, the retard control oil passage 93, the outer peripheral groove 51b,
Retard control oil passage 89, retard control oil passage 87, retard control oil passage 8
5, retard oil passage opening 81, and recesses 62b, 63
It is supplied to the second pressure chamber 71 of the variable valve timing actuator 24 via b, 64b, 65b. Also,
The hydraulic oil in the first pressure chamber 70 of the variable valve timing actuator 24 is released from the recesses 62a, 63a, 64.
a, 65a, advance oil passage opening 80, advance control oil passage 8
4, advance control oil passage 86, advance control oil passage 88, outer peripheral groove 51
a, an oil pan 13a through an advance control oil passage 92, a second oil control valve 94, and a discharge passage 96.
It is returned inside. As a result, the vane rotor 61 relatively rotates in the retard direction with respect to the housing 59, and the opening / closing timing of the intake valve 20 is delayed as described above.

Further, when the power supply to the electromagnetic solenoid 116 is controlled and the spool 118 is positioned in the middle of the casing 102, the first supply / discharge port 104 and the second supply / discharge port 106 are closed, and the supply / discharge port 104, Movement of hydraulic oil through 106 is prohibited. In this state, the first pressure chamber 7 of the variable valve timing actuator 24
0 or the second pressure chamber 71 is not supplied / discharged with hydraulic oil, and the first pressure chamber 70 and the second pressure chamber 71 are filled with hydraulic oil and held.
The rotation relative to 9 stops. As a result, the opening / closing timing of the intake valve 20 is maintained at the state when the vane rotor 61 is fixed.

The variable valve timing mechanism of the present embodiment includes a variable valve timing actuator 24,
A second oil control valve (OCV) 94 is provided.

In the above-described variable lift amount mechanism and variable valve timing mechanism, the OCV 36 and OV
CV94 is an electronic control unit (hereinafter referred to as "ECU")
The drive is controlled through 130, and the control changes the opening / closing characteristics of the intake valve 20. The ECU 130 includes a CPU 132, a ROM 133, an R
It is configured as a logical operation circuit including the AM 134, the backup RAM 135, and the like.

Here, the ROM 133 is a memory for storing various control programs and tables and maps referred to when the various control programs are executed. CP
U132 executes an arithmetic process necessary for control based on various control programs stored in the ROM 133. Also,
The RAM 134 is a memory for temporarily storing the calculation results of the CPU 132, data input from each sensor, and the like. The backup RAM 135 is a non-volatile memory for storing data to be stored when the engine 11 is stopped. Then, the CPU 132, the ROM 133, and the RAM 13
4 and the backup RAM 135 are connected to each other via a bus 136, and are also connected to an external input circuit 137 and an external output circuit 138.

The external input circuit 137 has a water temperature sensor 12
7, not shown intake pressure sensor and throttle sensor, etc.
Various sensors for detecting the operation state of the engine 11, a crank angle sensor 123 and a cam angle sensor 126
Is connected. The external output circuit 138 has O
CV36 and OCV94 are connected.

In the present embodiment, the ECU 1 having such a configuration
The valve characteristic control of the intake valve 20 is performed through 30. In particular, even when the three-dimensional cam illustrated in FIG. 2 is used, the intake camshaft 22 can be controlled by setting the torsion angle of the helical spline 61b. Is displaced in the axial direction, the opening timing of the intake valve 20 is constant,
Only the valve closing timing is changed.

In this way, the following problem that occurs when the valve lift variable actuator and the valve timing variable actuator 24 are combined to perform more detailed valve characteristic control is avoided. That is, in order to accurately determine the valve timing, it is not sufficient to control only the variable valve timing actuator 24, and it is necessary to consider the operation state of the lift variable actuator 22a which determines the lift characteristics. There is a problem that the adjustment of the control amount by the actuator becomes complicated.

Therefore, in the present embodiment, the above-mentioned helical spline 61b is used to adjust the torsion angle of the intake valve when the valve lift is the maximum and the intake valve when the valve lift is the minimum. The above-mentioned problem is avoided by setting the crank angle difference from the valve opening timing.

As a result, in the valve characteristic control of the intake valve 20, a variable valve timing mechanism is used for controlling the opening timing of the intake valve 20, and the intake valve 2 is controlled.
Regarding the valve lift amount of 0, the valve characteristics can be controlled to desired values by independently controlling the valve lift amount variable mechanisms.

The valve characteristics for controlling the variable valve lift mechanism and the variable valve timing mechanism by the ECU 130 are calculated based on the detection results of the cam angle sensor 126 and the crank angle sensor 123 described above. Here, the moving position of the intake cam 27 in the axial direction of the intake camshaft 22 and the crankshaft 15
The structure for detecting the amount of change in the relative rotational phase of the intake camshaft 22 with respect to the rotation angle will be described with reference to FIGS. 1, 7, and 8. FIG.

As shown in FIG. 1, the crankshaft 15
In the outer peripheral surface at the end opposite to the pulley 15a,
A pair of crank-side detected portions 123a made of a magnetic material is protruded, and a crank angle sensor 123 is provided near an end of the crankshaft 15. Also, on the outer peripheral surface of the intake side camshaft 22 opposite to the end opposite to the variable valve timing actuator 24, a pair of a reference detection portion 126a and a movement amount detection portion 126b, which are also made of a magnetic material. A cam angle sensor 126 is provided near the end of the intake side camshaft 22.

As shown in FIGS. 7 (a) and 7 (b), the pair of crank-side detected portions 123a
, And the angular interval between the crank-side detected portions 123a about the axis of the crankshaft 15 is 180 °. Then, when the crankshaft 15 rotates, the pair of crank-side detected portions 123 a pass by the crank angle sensor 123 in the rotation direction of the crankshaft 15. If the crank side detected part 123a and the crank angle sensor 123 pass each other,
A current is induced in the crank angle sensor 123, and the current is output from the sensor 123 as a pulse signal.

As shown in FIGS. 8 (a) and 8 (b), the pair of reference detected parts 126a extend linearly in the axial direction of the intake camshaft 22, and the reference detected parts 126a Is 180 ° with respect to the axis of the intake-side camshaft 22. On the outer peripheral surface of the intake-side camshaft 22, a pair of reference detected portions 1
In the position corresponding to between 26a, the movement amount detected portion 126
b, and the movement-amount-detected portion 126 b spirally extends in the axial direction of the intake-side camshaft 22. Then, when the intake-side camshaft 22 rotates, the pair of reference detected portions 126a and one movement amount detected portion 126a.
b indicates the intake camshaft 2 relative to the cam angle sensor 126.
Pass each other in the direction of rotation 2. When the cam angle sensor 126 and the reference detected portion 126a and the moving amount detected portion 126b pass each other, a current is induced in the cam angle sensor 126, and the current is output from the sensor 126 as a pulse signal. .

Next, the electrical configuration of the valve characteristic control device according to the present embodiment will be described with reference to FIG. In this valve characteristic control device, the first OCV 36 and the second OCV 94 are provided by an electronic control unit (hereinafter referred to as “ECU”).
), And the opening / closing characteristics of the intake valve 20 are changed by the control. This ECU1
Reference numeral 30 denotes a theoretical operation circuit including a ROM 133, a CPU 132, a RAM 134, a backup RAM 135, and the like.

Here, the ROM 133 is a memory for storing various control programs, maps referred to when the various control programs are executed, and the like. The CPU 132 executes desired arithmetic processing based on various control programs stored in the ROM 133. Further, the RAM 135 is a memory for temporarily storing the calculation result of the CPU 132, data input from each sensor, and the like, and the backup RAM 135 is a nonvolatile memory for storing data to be stored when the engine 11 is stopped. And ROM
The CPU 133, the CPU 132, the RAM 134, and the backup RAM 135 are connected to each other via a bus 136, and are connected to an external input circuit 137 and an external output circuit 138.
Is connected to

The external input circuit 137 includes a rotation speed sensor (not shown) for detecting the rotation speed NE of the engine 11, an intake pressure sensor for detecting the intake pressure PM of the engine 11, and a water temperature sensor for detecting the water temperature TA of the engine 11. Various sensors for detecting the operating state of the engine 11, such as a throttle sensor and the like, are connected to the crank angle sensor 123 and the cam angle sensor 126. Also, the external output circuit 13
8 is connected to the first OCV 36 and the second OCV 94.

In this embodiment, the ECU 1 having such a configuration is used.
Through 30, valve characteristic control of the intake valve 20 is performed. That is, the ECU 130 controls the driving of the second OCV 94 based on detection signals from various sensors (not shown) for detecting the operating state of the engine 11, and
The variable valve timing actuator 24 is operated so that 0 is the opening / closing timing (target value VVA) suitable for the operating state of the engine 11. Further, the ECU 130 controls the driving of the first OCV 36 based on the detection signals from the various sensors, and the valve opening time and the valve lift amount of the intake valve 20 are set to values (target value VL) suitable for the operating state of the engine 11.
The variable lift actuator 22a is operated so as to satisfy A).

On the other hand, the ECU 130 inputs pulse signals from the crank angle sensor 123 and the cam angle sensor 126. That is, in synchronization with the rotation of the crankshaft 15,
The crank angle sensor 123 includes a pair of the crank side detected parts 1.
A pulse P1 at an equal interval corresponding to 23a is generated. or,
In synchronization with the rotation of the intake camshaft 22, the cam angle sensor 126 generates a pulse P2 corresponding to the pair of reference detected portions 126a and a pulse P3 corresponding to one movement amount detected portion 126b.

Then, the ECU 130 detects the opening / closing timing of the intake valve 20 based on the pulse P1 and the pulse P2 (detected value VVR), and based on the pulse P2 and the pulse P3.
Is detected (detected value VLR). As described above, by detecting the actual valve characteristics related to the control of the variable valve timing actuator 24 and the variable lift amount actuator 22a, they are respectively set to the target value VV.
A, feedback control for converging to VLA is performed.

In the valve characteristic control, for the control of the variable valve timing actuator 24, for example, a learning control described in Japanese Patent Application Laid-Open No. 8-338271 can be used.

Next, a control mode of the lift variable actuator 22a according to the present embodiment to which the valve characteristic control according to the present invention is applied will be described. As described above, the ECU 130 is supplied with the operating state of the engine 11 as detection signals from the various sensors, and based on these signals, the valve lift becomes a value (target value VLA) suitable for the operating state of the engine 11. In order to operate the lift variable actuator 22a as described above, the control command value is calculated. This control command value is the drive duty ratio DVL for driving the lift variable actuator 22a.

The drive duty ratio DVL and the lift variable actuator 2 based on the drive duty ratio DVL
FIG. 9 shows the relationship between the operation speed 2a, that is, the speed of the intake camshaft 22.

As shown in FIG. 9, when the drive duty ratio DVL has a certain value KVL0, the displacement speed of the intake camshaft 22 becomes "0" and the lift amount variable mechanism is held and controlled. And, after this value KVL0,
When the drive duty ratio DVL is set to a value larger than the same KVL0, the lift amount variable actuator 22a
Since the camshaft 22 is displaced in the direction A in FIG. 1, the intake valve 20 shifts toward the high lift side.

On the other hand, when the drive duty ratio DVL is the same value KV
When the value is set to a value smaller than L0, the camshaft 22 is moved by the lift amount variable actuator 22a to A in FIG.
Since the intake valve 20 is displaced in the opposite direction, the intake valve 20 shifts to the low lift side.

Under such circumstances, in the present embodiment, the drive duty ratio DVL (the value KV in FIG. 9) at which the displacement speed of the lift amount variable actuator 22a becomes "0".
L0) is set as the hold command value KVL. Further, the drive duty ratio DVL in each case is set by the following equation (1). DVL = (VLA−VLR) × K + KVL (1) According to the above equation (1), when the detected value VLR is smaller than the target value VLA, control is performed to the high lift amount side.
Drive duty ratio DVL is set to be larger than hold command value KVL. Here, the target value VLA and the detected value V
A value larger than the holding command value KVL only by multiplying the difference (VLA-VLR) from the LR by the coefficient term K is set as the drive duty ratio DVL.

On the other hand, when the detected value VLR is larger than the target value VLA, the drive duty ratio DVL is set to a value (VL) larger than the hold command value KVL in order to perform control to the low lift amount side.
(A-VLR) × K.

By setting the drive duty ratio DVL in this manner, control is performed so that the valve lift of the intake valve 20 approaches the target value VLA. Then, the detected value VLR of the valve lift amount of the intake valve is set to the target value VL.
When approximation is made to A, the lift control of the lift amount variable actuator 22a is performed based on the hold command value KVL, whereby
The valve lift is held at that value.

By the way, when the detected value VLR of the valve lift of the intake valve 20 approximates the target value VLA, the value KVL0 is set as the hold command value KVL in order to promptly shift to the hold control. Is preferred.
By setting this value KVL0 as the holding command value KVL, the control of the valve lift amount of the intake valve 20 can be promptly shifted from the variable control to the holding control.

However, as mentioned above,
Since this value KVL0 changes due to tolerance, aging, and the like of the lift amount variable actuator 22a including the hydraulic pressure supply system, the value KVL0 is changed to the holding command value KVL.
If the fixed value is set as a fixed value, there is a concern that a deviation may occur in the holding position during actual control, or control hunting or the like accompanying the feedback control may occur. Therefore, in the present embodiment, the change amount of the detected value VLR of the valve lift amount is “0” and the drive duty ratio D
When the change amount of VL is “0”, the target value VL
Even if the deviation between A and the detected value VLR is not necessarily “0”, the learning control for updating the drive duty ratio DVL as a new holding command value KVL is performed based on the assumption that the deviation is caused by the above-mentioned tolerance and aging. I'm going to do it.

Here, the learning control mode according to the present embodiment will be described with reference to the time chart of FIG.
In this example, an example is shown in which the holding command value KVL is set to a value WKVL shown in FIG. 9 that is apart from an appropriate value KVL0 due to the above-mentioned tolerance or aging. First, at time t1, since the detection value VLR is smaller than the target value VLA, in the equation (1) for calculating the drive duty ratio DVL, the drive duty ratio DVL is a value larger than the holding command value KVL (here, WKVL). Is set to For this reason, the lift amount of the intake valve 20 is controlled to a higher lift side, and the detection value VLR approaches the target value VLA.

However, since holding command value KVL is set to value WKVL, detection value V
Although the LR is smaller than the target value VLA, the lift amount is controlled to be maintained. That is, equation (1)
, The sum of the value (VLA−VLR) × K and the holding command value WKVL in which this deviation has occurred is the value KVL.
Since it has become equal to 0, the lift amount is controlled to be held.

Therefore, in the present embodiment, time t2 to time t
In the period up to 3, the detection value VLR and the drive duty ratio DVL
Is confirmed to be unchanged, the current drive duty ratio DVL is updated as the hold command value KVL. As a result, the drive duty ratio DVL represented by the equation (1) becomes
Since the holding command value KVL is larger than the holding command value KVL by the value (VLA−VLR) × K, the lift amount of the intake valve 20 is:
Again, control is performed toward the high lift side. Thus,
The detection value VLR is controlled so as to approach the target value VLA.

The learning control is performed as described above, and the holding command value KV
By updating L each time, the valve lift amount of the intake valve 20 is appropriately controlled. By the way, if the value of the above-mentioned holding command value KVL is not an appropriate value during a transitional period until it is updated to the appropriate holding command value KVL by such learning control, the valve lift amount of the intake valve 20 becomes the target value VLA. Can be quite far away. The deviation from the target value VLA is particularly serious when the lift amount is excessively large because it may cause misfire or engine stall.

Therefore, in the embodiment, the value of the drive duty ratio DVL at which the valve lift of the intake valve 20 becomes relatively small is stored as the initial value KVLI of the holding command value KVL.

When the following conditions (c1) to (c3) are satisfied, the holding command value KVL is initialized with the initial value KVLI to control the valve characteristics of the variable valve lift mechanism. (C1) When the engine 11 enters the operating state for the first time. (C2) The engine 11 after being replaced with a new battery
Is operated first. (C3) When the variable valve lift mechanism recovers from the failure and can be controlled normally.

That is, if any one of the above conditions (c1) to (c3) is satisfied, the holding command value KVL may be considerably apart from an appropriate value. During the transitional period until the holding command value KVL is updated to the proper holding command value KVL, the initial value KVLI is set as the holding command value KVL.

Next, a control procedure of the valve characteristic control of the present embodiment incorporating such learning control will be described with reference to FIGS. FIG. 11 and FIG. 12 are routines showing a learning control procedure and a valve lift control procedure of the present embodiment. This routine is periodically executed by the ECU 130, for example, by interruption for a predetermined time.

In these control procedures, first, in step 100, the ECU 130 instructs the ECU 130 to show various parameters indicating the operating state of the engine 11, that is, the water temperature TA and the intake pressure P.
M, the rotational speed NE, etc., and the detected value VLR of the lift amount are read. In step 110, the target value VLA of the lift amount of the intake valve 20 is calculated from the parameters TA, PM, NE, and the like by, for example, a map calculation.

In the following step 120, it is determined whether or not the engine 11 satisfies any one of the conditions (c1) to (c3). Then, when this logical sum condition is satisfied, the process proceeds to step 130. In step 130, based on the above-described reason, the initial value KVL is set so that the valve lift becomes relatively small.
At I, the holding command value KVL is initialized.

On the other hand, in step 120, if none of the above conditions (c1) to (c3) is satisfied, or after completing the initialization in step 130, the process proceeds to step 140 (FIG. 12).

In step 140, the target value VL
The absolute value of the difference between A and the detected value VLR is compared with a predetermined value α. If the absolute value of the difference between the target value VLA and the detection value VLR is equal to or smaller than α, the process proceeds to step 190, where the drive duty ratio DVL is calculated based on the above equation (1).
Is calculated.

On the other hand, if the absolute value of the difference between the target value VLA and the detected value VLR is larger than α in step 140, the process proceeds to step 160. This step 160
In, it is determined whether or not the detection value VLR is in a continued state (whether or not the variation ΔVLR of the detection value is “0”). If the detected value VLR is in a changing state, it is determined that the lift amount control is a transitional time when the control is performed toward the target value VLA, and the process proceeds to step 190 to calculate an appropriate drive duty ratio DVL. Transition.

On the other hand, in step 160, the detected value V
When it is determined that LR is fixed, the process proceeds to step 170. In step 170, it is determined whether the drive duty ratio DVL has not changed (whether the change amount of the drive duty ratio ΔDVL = "0"). If the drive duty ratio DVL has changed, it is determined that this is also a transitional time when the lift amount control is controlled toward the target value VLA, and a step for calculating an appropriate drive duty ratio DVL is performed. Move to 190.

If it is determined in step 170 that the drive duty ratio DVL has not changed, the process proceeds to step 181. At this time, it is determined that the lift amount detection value VLR has not converged to the target value VLA and that there is no transitional time when the lift amount control is controlled toward the target value VLA. It is known from the judgment conditions. Therefore, the holding command value K
It can be determined that there is a high possibility that the VL is not appropriate. Therefore, in this case, the holding command value KVL is learned and updated. In the present embodiment, when the learning update is performed,
The following restrictions on steps 181 and 182 are provided.

First, the duty ratio DV related to the holding control
The value of L (the holding command value KVL) changes depending on the temperature of the engine 11. That is, the holding command value KVL has a characteristic that it is high on the low temperature side and the high temperature side, and low in the temperature range between them. Therefore, in the previous operation, when the holding command value KVL is updated by the learning control when the engine 11 is in the intermediate temperature range, if the cold start is performed in the next operation, the previously updated holding command value is used. Since the valve characteristic control is performed based on the value KVL, a significant control error may occur. Therefore, in the present embodiment, in step 181, the engine 11
It is determined whether the temperature TA is equal to or higher than the predetermined temperature β,
Only when A is equal to or higher than the predetermined temperature β, the learning update of the holding command value KVL by the learning control according to step 183 is performed. In other words, the temperature TA is equal to the predetermined temperature β.
When it is less than the above, learning update is prohibited.

Further, there is a limit on the control range of the lift amount by the variable valve lift amount mechanism. If the target value VLA for the lift amount control is close to the control limit of the variable valve lift amount mechanism, the variable valve lift amount mechanism may temporarily stop operating due to mechanical restrictions. In addition, there may be variations in the restriction due to individual differences between the variable mechanisms. Therefore, when the target value VLA is close to the control limit of the variable valve lift mechanism, the holding command value KVL is updated to an inappropriate value if the variable valve lift mechanism temporarily stops operating for the above-described reason. There is a concern. Therefore, in the present embodiment, it is determined in step 182 whether or not the target value VLA is near the control limit (variable limit). Even when the target value VLA is near the control limit of the variable lift amount mechanism, it is determined. , Learning updates are prohibited.

In this embodiment, the learning update according to step 183 is executed only when the conditions of steps 181 and 182 are cleared, and otherwise, the update of the holding command value KVL is performed. The process proceeds to step 190 without being performed.

In step 190, the drive duty ratio DVL is calculated based on the above equation (1) as described above, and the routine proceeds to step 200. In step 200, the OCV 36 is controlled based on the drive duty ratio DVL calculated in step 190,
This routine is ended once.

According to the valve characteristic control apparatus of the present embodiment for performing the learning control and the valve characteristic control in the manner and procedure described above, the following effects can be obtained. (1) When the detection value VLR is in a continuation state at a certain value,
By comparing the target value VLA with the detected value VLR, it is possible to determine whether the holding command value KVL is appropriate. If the target value VLA and the detected value VLR are not approximate, it is possible to correct this assuming that the holding command value KVL is not appropriate. For this reason, the valve lift can be accurately controlled, and the valve can be promptly shifted to a desired lift.

(2) The control value for controlling the variable valve lift mechanism so that the valve lift of the intake valve 20 becomes relatively small is set to the initial value KVL of the holding command value KVL.
By setting it as I, it is possible to avoid inconveniences such as misfire and engine stall caused by an inappropriate holding command value KVL before the learning control is started.

(3) The learning and updating of the holding command value KVL is performed only when the water temperature TA of the engine 11 is equal to or higher than the predetermined temperature β. In the intermediate temperature region where the temperature tends to be greatly different, the holding command value KVL is not updated. Therefore, in the intermediate temperature range, the holding command value K
It is possible to avoid a concern that a remarkable control error occurs in the valve characteristic control when the VL is updated and the cold start is performed thereafter.

(4) The target value VLA of the valve lift amount is
By prohibiting the updating of the hold command value KVL when the lift limit variable mechanism is near the control limit, an inappropriate hold command value is set when the lift amount variable mechanism temporarily stops operating due to mechanical restrictions. The problem of learning KVL can be avoided.

The present embodiment described above may be modified and implemented as follows. In the above embodiment, the conditions (c1) to (c)
When the condition 3) is satisfied, the holding command value KVL is initialized to the designated initial value KVLI. However, the conditions for this initialization may be changed as appropriate.

In the above embodiment, as shown in step 182 in FIG. 11, when the target value VLA is near the lift variable limit, the learning control is prohibited. May be allowed while limiting. By doing so, the target value VL
Even when A is near the lift variable limit, the holding command value KVL can be updated as needed.

In the above embodiment, the learning control is prohibited when the temperature (including the water temperature, oil temperature, etc.) TA of the engine 11 is lower than the predetermined temperature β as shown in step 181 of FIG. This processing is not essential for the device according to the present invention.

At the time of the learning control, the holding command value KVL is separately updated in each temperature range of the engine 11 in the cold region and the warm region, and in the intermediate temperature region, The learning value may be interpolated. That is, in this case, as shown in FIG. 13, after “YES” is determined in step 170 of FIG. 12, the temperature range of the temperature TA is determined as this new step 184. When it is determined that the temperature TA is in the cold range or the warm range, the drive duty ratio DVL at that time is changed to the cold range holding command value KVL in the form of step 183a or step 183b, respectively.
(A) or learning as the warm zone holding command value KVL (B). When the temperature TA is in the middle range, the holding command value KVL (A) and the holding command value (B) are interpolated to determine the middle range holding command value KVL (C). Then, by executing the calculations of steps 190a to 190c based on the learned or obtained learning values,
The drive duty ratio DVL at that time is obtained.

In the above embodiment, the detected value VLR
Does not converge to the target value VLA and the value of the detection value VLR becomes constant, so that it is determined that the hold command value KVL is not set to an appropriate value.
Not only when there is a problem with the setting of the hold command value KVL,
It can also be caused by a failure in which the valve lift is locked for some reason. In this case, there is a concern that erroneous learning is performed by the learning control according to the above embodiment. Therefore, when the detection value VLR does not converge to the target value VLA and the value of the detection value VLR becomes constant, a process of determining whether there is an abnormality in the valve lift variable mechanism may be performed. For example, the detection value VLR and the target value VLA
When the detected value VLR does not show a large change for a predetermined period during a predetermined period of time, a determination may be made that the valve lift variable mechanism is abnormal. In addition, any method can be adopted as a method of determining the presence or absence of the abnormality.

In the above embodiment, there is no restriction on the operation mode of the variable valve timing mechanism for the learning control of the variable valve lift mechanism. When the operation of the variable timing mechanism is controlled, there is a concern that the detection accuracy of the detection value VLR of the lift amount may be reduced. For example, during learning control of the variable valve lift amount mechanism, the variable valve timing mechanism is fixedly controlled. May be. Further, at this time, if the variable valve timing mechanism is fixedly controlled at the most retarded opening / closing timing,
During the holding learning control of the lift amount variable mechanism, it is possible to preferably prevent the overlap amount from becoming excessive. Conversely, the variable valve lift mechanism may be fixedly controlled during learning control of the variable valve timing mechanism. Also in this case, if the variable lift amount mechanism is fixedly controlled with the minimum lift amount, it is possible to preferably prevent the overlap amount from becoming excessively large during the holding learning control of the variable valve timing mechanism. Further, the learning control of the variable valve timing mechanism may be set to be started on condition that the learning control of the variable valve lift mechanism is normally performed. In this way, by prioritizing the learning control of the variable valve lift mechanism, the early stabilization of the holding control through the variable valve lift mechanism can be achieved.

In the above embodiment, the valve lift amount is detected through the cam angle sensor 126 and the reference detected portion 126a and the movement detected portion 126b. However, the valve lift amount is detected. The means is not limited to this, and is arbitrary.

In the above embodiment, the camshaft 22 and the variable valve timing actuator 24 are engaged by the helical spline 61b, but a straight spline may be used. Even in this case,
By controlling one of the variable lift amount mechanism and the variable valve timing mechanism while controlling the operation of the other mechanism, the learning control can be accurately performed.

In the above embodiment, the variable lift amount mechanism and the variable valve timing mechanism are provided in the intake system. However, they may be provided in the exhaust system, or may be provided in both the intake system and the exhaust system.

In the above embodiment, how to perform learning control of the variable valve lift mechanism for an engine using both the variable valve lift mechanism and the variable valve timing mechanism has been mainly described. Control is
The same can be applied to an engine having only a variable valve lift mechanism.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment embodying a valve characteristic control device for an internal combustion engine according to the present invention.

FIG. 2 is a perspective view illustrating the shape of an intake cam used for an intake camshaft according to the embodiment.

FIG. 3 is a configuration explanatory view of a variable valve lift actuator.

FIG. 4 is a diagram illustrating the configuration of a variable valve timing actuator.

FIG. 5 is a perspective view showing the shapes of an inner gear and a sub gear used in a variable valve timing actuator.

FIG. 6 is an explanatory diagram of an internal configuration of a variable valve timing actuator.

FIG. 7 is an exemplary perspective view of a crank angle detecting unit according to the embodiment;

FIG. 8 is a perspective view of a cam angle detecting unit according to the embodiment.

FIG. 9 is a graph showing a relationship between a drive duty ratio and a displacement speed of a variable lift amount actuator 22a.

FIG. 10 is an exemplary timing chart showing an example of learning control according to the embodiment;

FIG. 11 is a flowchart showing a valve lift amount control procedure of the embodiment.

FIG. 12 is a flowchart showing a valve lift amount control procedure of the embodiment.

FIG. 13 is a flowchart showing a valve lift amount control procedure according to a modified example of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Variable valve mechanism, 20 ... Intake valve, 21 ... Exhaust valve, 22 ... Intake side camshaft, 22a ... Lift amount variable actuator, 22b ... End outer peripheral surface of intake side camshaft, 24 ... Valve timing variable actuator,
24a: timing pulley, 26: timing belt,
27 intake cam, 28 exhaust cam, 31 cylinder tube, 31a first pressure chamber, 31b second pressure chamber, 32
... Piston, 33 ... End cover, 33a ... Auxiliary shaft, 33b ... Bearing, 34 ... First supply / discharge passage, 35 ... Second supply / discharge passage, 36 ... First oil control valve (OC)
V), 37: supply passage, 38: discharge passage, 39: casing, 40: first supply / discharge port, 41: second supply / discharge port,
42 first discharge port 43 second discharge port 44
Supply port, 45: Valve, 46: Coil spring, 4
7 electromagnetic solenoid, 48 spool, 51 cylindrical part of timing pulley, 51a, 51b outer peripheral groove, 51c inner peripheral surface, 52 disk part of timing pulley, 53 external teeth,
54: inner gear, 54a: large diameter gear, 54b: small diameter gear, 55: bolt, 56: sub gear, 56a: external teeth, 56b: internal teeth, 57: spring washer, 58 ...
Bolt, 59 housing, 59a inner peripheral surface, 60 cover, 60a hole, 61 vane rotor, 61a
Outer peripheral surface, 61b: helical spline, 61c: cylindrical space, 62, 63, 64, 65: wall, 62a, 63
a, 64a, 65a ... concave portions, 62b, 63b, 64b,
65b: recess, 66, 67, 68, 69 ... vane, 70
... First pressure chamber, 71... Second pressure chamber, 80... Advance oil passage opening, 81. Retard oil passage opening, 84, 86, 88. ... retard control oil passage, 90 ...
Lubricating oil passage, 91 ... inner peripheral groove, 92 ... advance control oil passage, 93 ...
Retard control oil passage, 94 ... second oil control valve,
Reference numeral 95: supply passage, 96: discharge passage, 102: casing, 104: first supply / discharge port, 106: second supply / discharge port, 107: valve portion, 108: first discharge port, 110
... second discharge port, 112 ... supply port, 114 ... coil spring, 116 ... electromagnetic solenoid, 118 ... spool, 123 ... crank angle sensor, 126 ... cam angle sensor, 126a ... reference detected part, 126b ... movement amount Detected part, 130... ECU.

Continued on the front page F-term (reference) 3G018 AA06 AB07 AB17 BA04 BA33 CA19 CA20 DA03 DA60 DA66 DA77 EA17 EA22 EA31 EA32 EA33 FA01 FA06 FA08 FA16 GA08 GA11 GA32 GA38 GA40 3G084 BA23 DA04 EA11 EB12 EB19 EB20 FA33 AA11 AB02 DA01 DA04 DA09 DA10 DF04 DF09 DG05 EA03 EA04 EA13 EA14 EA25 EC01 EC05 FA06 HA05Z HA13X HE01Z HE08Z

Claims (9)

[Claims] 1. A camshaft provided with a three-dimensional cam whose cam profile continuously changes in a cam axis direction,
A valve lift variable mechanism for varying a valve lift of an engine valve in accordance with a displacement position of the camshaft in a cam axis direction based on a hydraulic pressure supply from a hydraulic pressure supply means, and the valve lift according to an operation state of the engine Target value calculating means for calculating a target value of the amount; detecting means for detecting the valve lift amount; when a detection value detected by the detecting means is near a target value calculated by the target value calculating means. Holding control means for controlling the oil pressure supply by the oil pressure supply means so that the valve lift amount is held, and when the detection value is continued in a certain state, the detected value is compared with the target value at that time. And a learning control means for performing a learning control for correcting the control command value based on the evaluation. Control device. 2. The valve characteristic control device for an internal combustion engine according to claim 1, wherein the learning control means controls the valve lift variable mechanism in a direction in which the valve lift becomes relatively small. A valve characteristic control device for an internal combustion engine, comprising: an initial value storage means for storing a value as a learning initial value. 3. The learning value updating device according to claim 1, wherein the learning control means permits the learning value to be updated only when the temperature of the engine is equal to or higher than a predetermined temperature. A valve characteristic control device for an internal combustion engine, further comprising permission means. 4. The valve characteristic control device for an internal combustion engine according to claim 1, wherein the target value of the calculated valve lift amount is close to a variable limit of the variable valve lift amount mechanism. A valve characteristic control device for an internal combustion engine, further comprising a prohibition unit that prohibits the learning control unit from updating a learning value. 5. The valve characteristic control device for an internal combustion engine according to claim 1, wherein the target value of the calculated valve lift amount is near a variable limit of the variable valve lift amount mechanism. A valve characteristic control device for an internal combustion engine, further comprising a limiting unit that limits updating of a learning value by the learning control unit. 6. A valve characteristic control apparatus for an internal combustion engine according to claim 1, wherein said learning control means includes a controller for controlling the engine in a different temperature range between a cold region and a warm region of the engine. A valve characteristic control device for an internal combustion engine, which separately updates a learning value and interpolates the learning value in an intermediate temperature range. 7. A camshaft provided with a three-dimensional cam whose cam profile continuously changes in a cam axis direction,
A valve lift variable mechanism that varies a valve lift of an engine valve in accordance with a displacement position of the camshaft in the cam axis direction based on a hydraulic supply from the first hydraulic supply; and a second hydraulic supply. A variable valve timing mechanism for varying the valve timing of the engine valve in response to a change in the relative rotational phase between the camshaft and the engine output shaft based on the hydraulic pressure supply; and First target value calculation means for calculating a target value; first detection means for detecting the valve lift amount; and a first detection value detected by the first detection means calculated by the target value calculation means. A first holding control means for controlling a hydraulic pressure supply by the hydraulic pressure supply means so as to maintain a valve lift amount when the value becomes close to the target value to be performed; When the value is continued in a certain state, the control value of the first holding control means is evaluated by comparing the first detection value with the target value at that time, and the control command value is determined based on the evaluation. First learning control means for performing learning control for correction; second target value calculation means for calculating a target value of the valve timing in accordance with an operating state of the engine; and second detection means for detecting the valve timing. Detecting means, such that the valve timing when the second detection value detected by the second detecting means is close to the target value calculated by the second target value calculating means is held.
A second holding control unit for controlling a hydraulic pressure supply by the hydraulic pressure supply unit; and when the second detection value is continued in a certain state, the second detection value is compared with a target value at that time, and the second holding value is compared with the second detection value. And a second learning control means for performing a learning control for correcting the control command value based on the evaluation, and performing a learning control of the variable valve lift amount mechanism. A valve characteristic control device for an internal combustion engine, wherein the variable valve timing mechanism is fixedly controlled, and the variable valve lift variable mechanism is fixedly controlled during learning control of the variable valve timing mechanism. 8. The fixed control of the variable valve timing mechanism during the learning control of the variable valve lift mechanism,
The control is performed on the most retarded side of the valve timing, and the fixed control of the variable valve lift mechanism during the learning control of the variable valve timing mechanism is performed on the minimum lift side of the variable valve lift. The valve characteristic control device for an internal combustion engine according to claim 7. 9. A camshaft provided with a three-dimensional cam whose cam profile continuously changes in the camshaft direction,
A valve lift variable mechanism that varies a valve lift of an engine valve in accordance with a displacement position of the camshaft in the cam axis direction based on a hydraulic supply from the first hydraulic supply; and a second hydraulic supply. A variable valve timing mechanism for varying the valve timing of the engine valve in response to a change in the relative rotational phase between the camshaft and the engine output shaft based on the hydraulic pressure supply; and First target value calculation means for calculating a target value; first detection means for detecting the valve lift amount; and a first detection value detected by the first detection means calculated by the target value calculation means. A first holding control means for controlling a hydraulic pressure supply by the hydraulic pressure supply means so as to maintain a valve lift amount when the value becomes close to the target value to be performed; When the value is continued in a certain state, the control value of the first holding control means is evaluated by comparing the first detection value with the target value at that time, and the control command value is determined based on the evaluation. First learning control means for performing learning control for correction; second target value calculation means for calculating a target value of the valve timing in accordance with an operating state of the engine; and second detection means for detecting the valve timing. Detecting means, such that the valve timing when the second detection value detected by the second detecting means is close to the target value calculated by the second target value calculating means is held.
A second holding control unit for controlling a hydraulic pressure supply by the hydraulic pressure supply unit; and when the second detection value is continued in a certain state, the second detection value is compared with a target value at that time, and the second holding value is compared with the second detection value. A second learning control means for evaluating a control command value of the holding control means, and performing a learning control for correcting the control command value based on the evaluation; and a learning control by the first learning control means. A valve control device for an internal combustion engine, wherein learning control is performed by the second learning control means on condition that the control is normally performed.