JP3391114B2 - Valve timing adjustment device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing adjusting device for adjusting the opening / closing timing (valve timing) of an intake valve and an exhaust valve according to the operating conditions of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, for example, in an engine intake air amount control device described in Japanese Patent Publication No. 1-59406, a relative rotational position adjusting device is provided between a cam shaft of an intake valve and a crank shaft of an engine. The piston is moved by the supply of hydraulic pressure to the advance chamber or the retard chamber of the relative position adjusting device through the solenoid valve, and thereby the relative rotational position between the cam shaft and the crank shaft is adjusted, and the intake valve Adjusting valve timing.

[0003]

By the way, in the above-mentioned device, since the relative rotational position between the cam shaft and the crank shaft is adjusted only by the switching control of the hydraulic flow passage by the solenoid valve, a slight advance angle or retardation is required. It was difficult to control the corners. Therefore, instead of the solenoid valve that merely controls the switching of the hydraulic flow path, a control valve that can control the hydraulic pressure according to the opening degree while switching the hydraulic flow path is adopted, and a drive signal is given to this control valve. Therefore, it is conceivable to adjust the valve timing to control a minute advance angle or retard angle. However, when such a control valve is used, variations in the drive signal and the valve timing vary from device to device due to variations in manufacturing of the control valve, oil leakage from the control valve, and the like. For example, there is a problem that the valve timing cannot be maintained as it is or that the valve timing cannot be changed.

To address this, Japanese Patent Laid-Open No. 6-159105
As shown in the publication, a hydraulic control valve that performs hydraulic control according to the opening degree together with the oil passage switching control is adopted, and when the operating state of this hydraulic control valve is a predetermined operating state, the drive signal is learned, The relative rotation angle between the crankshaft and the camshaft is made to match the target rotation angle by performing the oil passage switching control and hydraulic control of the hydraulic control valve by the drive signal calculated by the control device based on the learning drive signal. A valve timing adjusting device is disclosed.

However, in this valve timing adjusting device, there is a problem that foreign matter is likely to be caught when the opening of the hydraulic control valve is narrowed down. If such biting occurs, the hydraulic control valve will lock,
The hydraulic opening control and the oil passage switching control are disabled. Therefore, if the learning of the drive signal is continued with the control disabled as described above, an abnormal value is included in the learning value.
As a result, the control deviation (that is, the difference between the target valve timing and the actual valve timing) in the valve timing adjustment device is abnormal because the learning value is abnormal when the foreign matter comes off and the hydraulic control valve returns to normal. There is a situation in which the engine performance becomes insufficient and the engine performance is not fully brought out.

Further, even after the foreign substance is not caught, a considerable amount of time is required until the learning value becomes a normal value due to the learning value update cycle and the limitation of the feedback control amount. There is also a problem that a state in which it cannot be fully withdrawn continues for a long time. In addition, when the learning value shifts significantly while foreign matter is caught, and the amount of change in the target valve timing after the foreign matter is cleared is small, etc., the control amount given by the feedback calculation due to the large shift in the learned value. There is a case in which the desired value is not changed and the learning value is not updated.

In view of the above-mentioned problems of the prior art, it is an object of the present invention to reliably achieve a desired valve timing in a valve timing adjusting device for an internal combustion engine so as to surely bring out a desired engine performance. To do.
Further, in view of the above-mentioned problems of the conventional technology, the present invention prevents the occurrence of a steady deviation by performing learning control of a control signal, and even if a temporary abnormality occurs in the valve timing adjustment device, An object of the present invention is to provide a valve timing adjustment device for an internal combustion engine that can quickly return to the control capability before the occurrence of an abnormality after the elimination.

Further, in view of the above problems of the prior art, the present invention is capable of preventing erroneous learning of a control signal even if a temporary abnormality occurs in the valve timing adjusting device. The purpose is to provide a device.

[0009]

In order to achieve the above object, in the invention according to claim 1, an internal combustion engine (1) is provided.
Phase difference adjusting device (40) for adjusting the phase difference between the crankshaft (2) and the camshaft (4, 5) according to the oil pressure, and the oil pressure to the phase difference adjusting device according to the opening degree. A control valve (30) for controlling, an opening adjusting means (49, 64) for adjusting the opening of the control valve, a crank shaft (2), a cam shaft (4,
5) actual valve timing detection means (48, 101) for detecting the actual valve timing of at least one of the intake valve and the exhaust valve based on the relative rotation angle with the intake valve, and the intake valve and A target valve timing setting means (48, 100) for setting a target valve timing of at least one of the exhaust valves, and a control signal for performing feedback control so that the actual valve timing matches the target valve timing. (4
Control signal output means (48, 10)
2) and a learning means (4) for learning a control signal to the opening degree adjusting means (49, 64) for setting the phase difference adjusting device (40) in a predetermined phase difference adjusting state based on the actual valve timing.
8, 103), and an abnormality determination means (4) for determining an abnormality of the feedback control in a valve timing adjustment device that adjusts the valve imming of at least one of the intake valve and the exhaust valve according to the learning of the learning means.
And 8,104), the abnormality when the determining means determines the abnormality, comprising a prohibiting means for prohibiting the learning by the learning means (48,103) (48,104), additionally the actual
The position of the phase difference adjusting device (40) based on the valve timing.
Phase difference adjustment state determination means for determining the phase difference adjustment state (4
(8, 102), and abnormality determination means (48, 104)
However, if the feedback control abnormality is determined, the phase difference
Based on the determination result of the adjustment state determination means and the control signal
There is provided a valve timing adjusting device for an internal combustion engine, which is characterized by performing the above.

[0010]

According to the invention of claim 2 ,
In the valve timing adjusting device according to item 1, when the control signal takes a value equal to or more than a predetermined value, it is determined that the changing direction of the actual valve timing is a predetermined direction, while the control signal is equal to or less than the predetermined value. When taking a value, a change direction determination means (48, 104, S1) for determining that the change direction of the actual valve timing is opposite to the predetermined direction.
04 to S132, S134), and the abnormality determination means (48, 104) determines the abnormality determination of the feedback control by the change direction determination means (48, 104, S104 to S132, S134). It is characterized in that it is performed based on the determination of the direction of.

[0012] In the invention of claim 3, claim
In the valve timing adjusting device according to item 1, a valve timing state determining means (48, for determining that the constant state of the actual valve timing continues for a predetermined time).
104) and control signal determination means (48, 104, S140) for determining that the control signal is within a predetermined range, and the abnormality determination means (48, 104) determines the feedback control abnormality. Valve timing state determination means (48, 104) and control signal determination means (48, 1)
04, S140).

[0013]

In the invention described in claim 4 , the internal combustion engine
Between the crankshaft (2) and the camshaft (4,5) of the function (1)
Phase difference adjusting device (4
0) and the hydraulic pressure to this phase difference adjusting device is controlled according to the opening degree.
Controlling the control valve (30) and adjusting the opening of this control valve
Opening degree adjusting means (49, 64), crankshaft (2) and cover
Intake valve and exhaust based on the relative rotation angle with the shaft (4, 5)
The actual valve timing of at least one of the valves
Valve timing detection means (48, 101) and internal combustion engine
Depending on the operating condition of Seki (1)
Target valve that sets the target valve timing for both
Timing setting means (48, 100) and the actual valve
Match the timing to the target valve timing
Adjustment of the control signal for feedback control
Control signal output means (4) for outputting to the means (49, 64)
8, 102) and the phase based on the actual valve timing.
An opening that brings the difference adjusting device (40) into a predetermined phase difference adjusting state
A learner who learns the control signal to the adjusting means (49, 64)
It is equipped with steps (48, 103) and is adapted to the learning of this learning means.
Accordingly, at least one of the intake valve and the exhaust valve has a valve valve.
In the valve timing adjustment device that adjusts the
Abnormality judging means for judging an abnormality in the feedback control
(48, 104), the abnormality determining means determines the abnormality.
When set, learning by learning means (48, 103) is prohibited
Comprising a stop prohibiting means (48,104), the actual valve timing range determining means for determining further before <br/> Symbol actual valve timing is in a predetermined range (48,104, S
160) is provided, and the abnormality determination means (48, 104) determines the abnormality of the feedback control based on the determination result of the actual valve timing range determination means (48, 104, S160).

[0015]

According to the inventions of claims 1 to 4 , when the abnormality judging means (48, 104) judges an abnormality in the feedback control, the prohibiting means (48, 10).
4) prohibits learning by the learning means (48, 103). Therefore, the learning value by the learning means (48, 103) is not mixed with the value due to the abnormality of the feedback control.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention applied to a double overhead cam type internal combustion engine 1 for a vehicle. In the internal combustion engine 1, the power from the crankshaft 2 is transmitted by the timing chain 3 to the exhaust side camshaft 4 and the intake side camshaft 5 via the sprockets 13a and 13b.

A phase difference adjusting device 40 is attached to the intake camshaft 5.
(See the hatched area in FIG. 1). A cam shaft position sensor 44 is attached to the cam shaft 5, and a crank position sensor 42 is attached to the crank shaft 2. Here, when the crank position sensor 42 generates N detection pulse signals with one rotation of the crankshaft 2, the camshaft position sensor 44 generates 2N detection pulse signals with one rotation of the camshaft 5. Has become. When the maximum value of the timing conversion angle of the camshaft 5 is θmax crank angle, N <360 degrees / θma
The number N of detection pulse signals is set so as to be x.

As a result, the actual valve timing of the intake valve is determined by the relative rotation angle θ between the detection pulse signal from the crank position sensor 42 and the detection pulse signal from the camshaft position sensor 44 that occurs subsequently to this detection pulse signal. Is calculated. Specifically, each detection pulse signal from the crank position sensor 42 and the cam shaft position sensor 44 is input to the microcomputer 48 of the internal combustion engine control device 46, and the actual valve timing is calculated based on this. Further, various detection signals generated from the intake air amount sensor, the water temperature sensor, the throttle sensor, etc. are also input to the microcomputer 48, and the target valve timing of the intake valve is calculated based on these signals.

Further, in the microcomputer 48, feedback control calculation is performed so that the actual valve timing of the intake valve matches the target valve timing. As a result, the linear solenoid 64 (spool valve 3
A control signal representing a target current to be supplied to the driving electromagnetic actuator (0) is output to the current control circuit 49 of the internal combustion engine controller 46. The current control circuit 49 has a circuit (not shown) that detects a current flowing through the linear solenoid 64. Then, the current control circuit 49 performs feedback control based on the control signal from the microcomputer 48 so that the detected current matches the target current. In addition,
The current feedback control part may be implemented as software and incorporated in the microcomputer 48.

The spool valve 30 is controlled under the feedback control as described above. Then, the hydraulic oil from the oil pan 28 is pressure-fed by the oil pump 29 via the spool valve 30 thus controlled, and the amount of hydraulic oil to the phase difference adjusting device 40 is controlled. Hereinafter, the configuration of the above-described phase difference adjusting device 40 will be described in more detail with reference to FIG.

The phase difference adjusting device 40 is attached to the cylinder head 25 of the internal combustion engine 1, as shown in FIG. The phase difference adjusting device 40 includes a cam shaft sleeve 11 having a substantially cylindrical shape, and the cam shaft sleeve 11 is
The large-diameter cylindrical portion is fitted coaxially with the left end portion of the cam shaft 5 shown in FIG. The hollow partition wall 11c of the camshaft sleeve 11 is connected to the end of the camshaft 5 by press fitting the pin 12 and tightening the bolt 10.
As a result, the cam shaft sleeve 11 rotates integrally with the cam shaft 5. An external tooth helical spline 11 a is formed on the outer peripheral surface of the large diameter cylindrical portion of the camshaft sleeve 11.

Further, the cam shaft sleeve 11 is provided with a small-diameter cylindrical portion 11b, and the small-diameter cylindrical portion 11b extends coaxially into the substantially cylindrical hollow portion of the housing 23. The housing 23 is attached to the cylinder head 25 by tightening bolts 24 at its flange portion 23a. The sprocket 13a is relatively rotatable with respect to the camshaft 5 while being sandwiched between the annular rib 5a of the camshaft 5 and the open end of the large-diameter cylindrical portion of the camshaft sleeve 11 so as to be immovable in the axial direction. It is coaxially supported. A substantially cylindrical sprocket sleeve 15 is coaxially attached to the left side surface of the sprocket 13a shown in FIG. 2 by press fitting the pin 14 and tightening the bolt 16 through the respective flange portions. This causes the sprocket sleeve 15 to rotate integrally with the sprocket 13a. This sprocket sleeve 15 has a cylindrical portion 1
5b, the cylindrical portion 15b coaxially extends into the hollow portion of the housing 23 so as to surround the camshaft sleeve 11.

At the intermediate portion of the inner peripheral surface of the cylindrical portion 15b,
An internal tooth helical spline 15a is formed, and the internal tooth helical spline 15a is formed on the camshaft sleeve 11
The external tooth helical spline 11a is formed to have a twist in the opposite direction. Either one of the external tooth helical spline 11a and the internal tooth helical spline 15a may be configured by a spline having straight teeth parallel to the axial direction with a twist angle of zero.

An annular space 90 having a substantially uniform cross section in the axial direction is formed between the small-diameter cylindrical portion 11b of the camshaft sleeve 11 and the cylindrical portion 15b of the sprocket sleeve 15 described above. In 90, a substantially cylindrical hydraulic piston 17 is coaxially supported by the camshaft sleeve 11 so as to be slidable in the axial direction and in a liquid-tight manner.

On the right side of the inner peripheral surface of the hydraulic piston 17, the external tooth helical spline 11 of the camshaft sleeve 11 is provided.
An internal tooth helical spline 17a that meshes with a is formed, while an external tooth helical spline 17b that meshes with the internal tooth helical spline 15a of the sprocket sleeve 15 is formed on the right side of the outer peripheral surface of the hydraulic piston 17. There is. As a result, the rotation of the crankshaft 2 transmitted to the sprocket 13a via the timing chain 3 (see FIG. 1) under the engagement of the respective splines engages the sprocket sleeve 15, the hydraulic piston 17, and the camshaft sleeve 11. It is transmitted to the camshaft 5 via.

An oil seal 70 is provided on the outer peripheral edge of the annular collar portion formed at the left end portion of the hydraulic piston 17 in the annular space 90.
It is mounted so as to make liquid-tight contact with the inner peripheral surface of 5b. In addition, a cross section L is formed in the left side portion of the inner peripheral surface of the hydraulic piston 17.
The annular leg portion 17c extending in a character shape collides with a central step portion (hereinafter, referred to as a right side stopper) of the cam shaft sleeve 11 and stops the right movement of the hydraulic piston 17.

By providing the hydraulic piston 17 in the annular space 90 as described above, the annular space 90 is
Is divided into two chambers. As a result, the advance side hydraulic chamber 2
2 is formed on the left side of the hydraulic piston 17, while the retard side hydraulic chamber 32 is formed on the right side of the flange portion of the hydraulic piston 17. Further, the sealability between the hydraulic chambers 22 and 32 is secured by the oil seal 70 described above.

An end plate 50 is coaxially attached to the left end opening of the sprocket sleeve 15. The end plate 50 is formed in an inverted L-shape in cross section by a cylindrical portion and an annular flange portion, and the annular flange portion of the end plate 50 is coaxially fixed to the left end opening of the sprocket sleeve 15. End plate 5
An annular groove is formed on the outer peripheral surface of the cylindrical portion 0, and an oil seal 71 is installed in the annular groove. The annular flange portion of the end plate 50 also serves as a stopper (hereinafter, referred to as a left side stopper) that stops the left movement of the hydraulic piston 17 due to the collision with the annular flange portion of the hydraulic piston 17.

End plate 50 and camshaft sleeve 1
On the left side of FIG. 1, a ring plate 51, which is formed in an annular shape with a U-shaped cross section, is coaxially attached to the camshaft sleeve 11 on the inner surface of the annular left side wall of the housing 23 by press fitting the knock pin 53. The cylindrical portion of the end plate 50 and the small diameter cylindrical portion 11b of the camshaft sleeve 11 are rotatably supported in the U-shaped right side surface of the plate 51. Further, an oil seal 72 is mounted in an annular groove formed on the outer peripheral surface of the small diameter side cylindrical portion of the ring plate 51. The oil seal 72 has a sealing property between the ring plate 51 and the cam shaft sleeve 11. Secure. On the other hand, the oil seal 71 described above ensures the sealing performance between the end plate 50 and the ring plate 51. As a result, the sealing property in the advance side hydraulic chamber 22 is secured.

A bolt 52 is coaxially fitted in the small-diameter cylindrical portion of the ring plate 51 and in the hollow portion of the annular left side wall of the housing 23. The bolt 52 has a right end surface which is fixed to the cam shaft sleeve 11. A cylindrical space 91 is formed between the inner peripheral surface of the small-diameter cylindrical portion and the hollow partition wall 11c. A hydraulic passage 61b is formed in a T-shaped cross section inside the bolt 52 as shown in FIG. 2, and the hydraulic passage 61b has a cylindrical space 91 at its axial passage portion.
It communicates with the inside. The hydraulic passage 61b communicates with the annular groove formed on the outer peripheral surface of the bolt 52 at both ends of the radial passage portion.

A hydraulic passage 61a is formed in the left wall portion of the housing 23 as shown in FIG. 2, and the hydraulic passage 61a is provided with a cylindrical space 91 via an annular groove of the bolt 52 and the hydraulic passage 61b. The camshaft sleeve 11 so as to communicate with the inside thereof and to open into the cylindrical space 91.
And communicates with the retard angle side hydraulic chamber 32 through the hydraulic passage 61c formed in the above. A hydraulic passage 60 communicating with the advance-side hydraulic chamber 22 is further formed in the left wall portion of the housing 23. These hydraulic passages 61a and 60 are provided in the housing 2
3 is formed in the left wall portion and opens into a cylindrical hollow portion 95 that accommodates a spool valve 30 described later. Also,
A hydraulic pressure supply passage 65 opens at the tip of the cylindrical hollow portion 95, and the hydraulic pressure supply passage 65 receives hydraulic oil pumped from an oil pan 28 of the internal combustion engine 1 by an oil pump 29. Supply into the cylindrical hollow portion 95. The hydraulic pressure release passage 66 is opened in the oil pan 28 to return the hydraulic oil into the oil pan 28.

Next, the structure of the spool valve 30 will be described with reference to FIG. The spool valve 30 is composed of a cylinder 30a constituted by the inner wall of the cylindrical hollow portion 95, and a spool 31 having a pair of left and right lands fitted in the cylinder 30a so as to be slidable in the axial direction. The cylinder 30a is formed with a hydraulic port 30b communicating with the hydraulic passage 61a and a hydraulic port 30c communicating with the hydraulic port 60. The cylinder 30a further includes a suction port 30 communicating with the hydraulic pressure supply passage 65.
d, both discharge ports 30e communicating with the hydraulic pressure release passage 66,
30f and are formed. The switching of the communication between the hydraulic ports 30b and 30c, the suction port 30d, and the discharge ports 30e and 30f and the control of the communication degree (opening degree of the spool valve 30) are performed by the cylinder 30 of the spool 31.
It is done by sliding in a.

A coil spring 31a is provided on the right end side of the spool 31 in the right end portion of the cylinder 30a shown in FIG.
A always biases the spool 31 to the left in the drawing.
On the other hand, a linear solenoid 64 is provided on the left end side of the spool 31 in the drawing, inside the left end portion of the cylinder 30a in the drawing. When an electromagnetic force is induced in the linear solenoid 64 according to the value of the current flowing through the linear solenoid 64,
This electromagnetic force causes the spool 31 to rotate the coil spring 31.
It slides to the right against the biasing force of a.

Hereinafter, the spool valve 30 configured as described above will be described.
The switching of communication of each hydraulic passage and the opening degree control by sliding the spool 31 will be described. As shown in FIG. 3A, when the spool 31 receives an electromagnetic force from the linear solenoid 64 and slides to the right against the urging force of the coil spring 31a, the suction port 30d and the hydraulic port 3 are moved.
0c communicates with each other by the right movement of the right side land of the spool 31 to connect the hydraulic pressure supply passage 65 and the hydraulic passage 60.
Therefore, the oil pressure from the oil pump 29 is pumped into the advance side hydraulic chamber 22. At the same time, the discharge port 30e and the hydraulic port 30b are communicated by the right movement of the left side land of the spool 31 to communicate the hydraulic passage 61a and the hydraulic release passage 66. Therefore, the hydraulic pressure in the retard side hydraulic chamber 32 is released. As a result, the hydraulic piston 17 is pushed to the right in the annular space 90 (see FIG. 2), so that the camshaft 5 rotates and advances relative to the sprocket 13a, that is, the crankshaft 2.

As shown in FIG. 3 (b), when the spool 31 is at the center, the discharge port 30 of the hydraulic port 30b.
The communication with e and the communication with the suction port 30d of the hydraulic port 30c are blocked by the lands on the left and right sides of the spool 31, respectively. Therefore, the position of the hydraulic piston 17 is maintained as it is when there is no leakage of hydraulic oil from the hydraulic chambers 22 and 32 on the advance side and the retard side. Therefore, the rotational phase difference between the sprocket 13a and the cam shaft 5, that is, the actual valve timing does not change.

As shown in FIG. 3 (c), when the spool 31 is biased by the coil spring 31a and slides to the left under the stop of the generation of the electromagnetic force from the linear solenoid 64, the suction port 30b and the hydraulic pressure. The port 30d communicates by the left movement of the left side land of the spool 31 to communicate the hydraulic pressure supply passage 65 and the hydraulic passage 61a. For this reason, the oil pressure from the oil pump 29 is pressure-fed to the retard side hydraulic chamber 32. On the other hand, the discharge port 30f and the hydraulic port 30c communicate with each other by the leftward movement of the right side land of the spool 31 to communicate the hydraulic passage 60 and the hydraulic release passage 66. Therefore, the hydraulic pressure in the advance side hydraulic chamber 22 is released. As a result, the hydraulic piston 17 is pushed to the left in the annular space 90, so that the cam shaft 5 rotates in the opposite direction to the above direction and retards relatively to the sprocket 13a, that is, the crank shaft 2. .

3A, 3B and 3C, the port 30b and the port 30e (or the port 30) are used.
d) the degree of communication with port 30c and port 30d
(Or port 30f), the degree of communication with the spool 31
Is controlled by the opening degree of each land on both the left and right sides with respect to each port 30b and 30c accompanying the right movement (or left movement). FIG. 4 is a characteristic diagram showing the relationship between the position of the spool 31 in the spool valve 30 (hereinafter referred to as the spool position) and the actual valve timing change speed under certain operating conditions of the internal combustion engine 1. In this characteristic diagram, the area where the actual valve timing change speed is positive corresponds to the area moving in the advance direction, while the area where the actual valve timing change speed is negative corresponds to the area moving in the retard direction. Equivalent to. The spool position on the horizontal axis in this characteristic diagram is proportional to the linear solenoid current.

In this characteristic diagram, each symbol (a),
3B and 3C respectively show spool positions corresponding to the positions of the spool 31 shown in FIGS. 3A, 3B, and 3C. The spool position where the actual valve timing does not change, as indicated by the symbol (b), is the amount of hydraulic oil leaking from the hydraulic chamber, the hydraulic piping, and the spool valve 31, and the oil pump 29.
There is only one point that is in balance with the amount of hydraulic oil pumped from. Further, this point is always changed because the characteristic changes as shown in FIG. 5 due to the change of the hydraulic oil discharge pressure due to the internal combustion engine speed and temperature. Also, due to variations in the product such as the winding resistance of the linear solenoid 64 and the size of the spool 31,
This point and the manner of changing the characteristics differ from product to product. The linear solenoid current at the point where the actual advance amount does not change is hereinafter referred to as a holding current.

When it is desired to advance the valve timing based on this holding current, the linear solenoid current is increased,
Conversely, when it is desired to retard the phase, the phase difference adjusting device 40 can be controlled by reducing the linear solenoid current. In such a case, since the spool position where the actual valve timing does not change as described above changes, it is understood that it is necessary to successively learn the holding current in order to control the valve timing accurately and stably.

FIG. 6 is a block diagram showing functionally divided structures corresponding to the various sensors shown in FIG. 1, the microcomputer 48, the current control circuit 49, the phase difference adjusting device 40 and other various elements. Target valve timing calculator 1
00 calculates the target valve timing based on the internal combustion engine operating conditions detected from various signals from the intake air amount sensor, the water temperature sensor, the throttle opening sensor, and the like.

The actual valve timing calculation unit 101 calculates the actual valve timing based on the signals from the crank position sensor and the cam shaft position sensor. Current calculation unit 102
Calculates a target current value for energizing the linear solenoid 64 based on the target valve timing, the actual valve timing, and the holding current learning value from the learning unit 103.

The learning unit 103 learns the holding current based on the actual valve timing and the target current value when there is no signal from the learning prohibition judging unit 104. Learning prohibition determination unit 10
Reference numeral 4 makes a learning prohibition judgment based on the actual valve timing and the target current value, and outputs a learning prohibition signal when the learning prohibition judgment is established. The feedback control unit 105 feedback-controls the current to the linear solenoid 64 based on the target current value, and operates the phase difference adjusting device 40.

FIG. 7 is a flow chart for calculating the target current value by the current calculator 102. Step S11
At 0, the control deviation e = ry is calculated from the target valve timing r and the actual valve timing y. In the next step S111, the feedback current If is calculated by the following equation by performing PD control calculation based on the control deviation e.

[0044]

## EQU00001 ## If = Kp.times.e + Kd.times.de / dt In the equation of the mathematical formula 1, the symbols Kp and Kd respectively represent constants. In step S112, the target current Id is calculated from the feedback current If and the holding current Ih by the following equation.

[0045]

## EQU00002 ## Id = If + Ih Next, the holding current learning in the learning unit 103 will be described. FIG. 8 is a flowchart for holding current learning in the learning unit 103. When the learning prohibition signal described later is not input from the learning prohibition determination unit 104, NO is determined in step S120, and it is determined in step S121 whether the actual valve timing is constant. If the actual valve timing is not constant, NO is determined in step S121, the learning counter is reset to T = 0 in step S124, and the arithmetic processing is ended.

When the actual valve timing is constant (corresponding to the predetermined phase difference adjustment state in claim 1), YES is determined in the step S121, and the value T of the learning counter has passed Xsec or more in the step S122. It is determined whether or not. If the value T of the learning counter has not elapsed for Xsec or more, NO is determined in step S122, and the arithmetic processing is ended as it is. When the value T of the learning counter has passed for Xsec or more, YES is determined in step S122, and the holding current is learned as Ih = Id in step S123, and then the learning counter is set to T in step S124. = 0 is reset and the arithmetic processing is terminated. Note that in step S120, when the learning prohibition signal is input from the learning prohibition determination unit 104, YES is determined,
In step S124, the learning counter is reset and the arithmetic processing is ended.

FIG. 9 shows an experimental result when control is started in a state where the holding current has not been correctly learned and the holding current is correctly learned at point A in the figure. The period in which the holding current is not correctly learned is a period in which the learned holding current Ihg and the true holding current Ihr do not match. At this time, the actual valve timing y with respect to the target valve timing r has a control deviation e in a steady state. Since the feedback current at this time is de / dt = 0 because of the steady state, I
f = Kp × e. The target current is Id = If + Ihg
= Kp × e + Ihg, but it can be seen that Id = Ihr because the actual valve timing does not change. Since Id is a value calculated in the microcomputer 48, it can be detected. Therefore, in the steady state,
By setting the holding current Ihg = Id, the correct holding current can be learned. In the figure, by correctly learning the holding current at the point A, the control deviation thereafter converges to zero.

Next, the operation of the phase difference adjusting device 40 when the spool valve 31 bites a foreign substance will be described with reference to FIGS. 10 and 11. In FIG. 10, when the actual valve timing y is feedback-controlled with respect to the change of the target valve timing r, the spool valve 31 bites the foreign matter at the point B where the opening degree of the spool valve 31 becomes small, and as it is, The test result when locked is shown.

Even after the passage of point B, the change speed of the actual valve timing does not decrease, and the advance of the hydraulic piston 17 of the phase difference adjusting device 40 continues to advance until it collides with the left side stopper, and the phase difference changes when colliding with the left side stopper. The actual advance amount becomes constant after stopping. At this time, the target current has a value smaller than the holding current in order to retard the valve timing, but the spool valve 30 does not operate because it is locked. In such a case, if step S120 of FIG.
In the state where 7 collides with the left stopper, step S1
The learning conditions of S21 and S122 are satisfied, and the holding current is learned with an abnormal value at point C in FIG.

FIG. 11 shows the test results when the spool valve 31 returns to the normal state as a result of the restoration procedure after the foreign matter biting abnormality is determined. Since the control deviation e is large, the phase difference adjusting device 4
Since the hydraulic piston 17 of 0 collides with the left stopper, it is determined that the foreign matter is caught abnormally.
The target current is greatly changed so as to remove the caught foreign matter. As a result, the spool 31 of the spool valve 30 slides in the cylinder 30a. As a result, the foreign matter comes off at the point D, and the spool valve 30 returns to normal. However, at this time, since the learning value of the holding current is a value greatly deviated from the true holding current, the control deviation e becomes large until the learning of the correct holding current is completed again. .

The present invention makes a learning prohibition determination in order to prevent erroneous learning of the holding current when such a foreign matter is caught in the spool valve. FIG. 12 shows respective characteristics of the upper limit product and the lower limit product of the product variation of the valve timing change speed with respect to the target current. The holding current does not become larger than the upper limit value Ihgx and does not become smaller than the lower limit value Ihgn. That is, if the spool valve 30 does not bite the foreign matter, the valve timing advances when the target current Id> the upper limit value Ihgx. On the other hand, Id <Ihg
When n, the valve timing should be retarded.
Therefore, when these are not established, the spool valve 30
Can be recognized as being in a foreign matter biting state.

FIG. 13 is a flowchart for the learning prohibition judgment by the learning prohibition judgment unit 104. Step S
At 130, the target current Id is the holding current upper limit value Ih.
It is determined whether or not it is larger than gx. If Id is larger than Ihgx, YES in step S130.
Then, in step S134, it is determined whether the actual valve timing is advanced. When it is determined that the operation is normal when the actual valve timing is advanced, after the determination of YES in step S134, the learning prohibition signal is released in step S135, and the arithmetic processing is ended. It If the actual valve timing is not advanced, it is determined that the spool valve 30 is biting a foreign matter, and after the determination of NO in step S134, the learning prohibition signal is set in step S133, and the arithmetic processing ends. To be done.

In step S131, the target current I
It is determined whether or not d is smaller than the holding current lower limit value Ihgn. If Id is smaller than Ihgn, step S
After the determination of YES in 131, it is determined in step S132 whether the actual valve timing is retarded. If the actual valve timing is delayed,
Based on the determination that the operation is normal, step S132
After the determination of YES in step S135, the learning prohibition signal is released in step S135, and the arithmetic process ends.
If the actual valve timing is not retarded, it is determined that the spool valve 30 is biting the foreign matter, and step S13 is performed.
After the determination of NO in 2 is made, in step S133, the learning prohibition signal is set, and the arithmetic processing is ended.

FIG. 14 shows the test results when this spool valve foreign matter entrapment determination is used in the above learning prohibition determination. When the actual valve timing y is feedback-controlled with respect to the change of the target valve timing r, the actual valve timing continues to advance when the spool valve 30 bites in and locks a foreign substance at point B. Then, after passing the point E, the target current Id exceeds the lower limit value Ihgn of the holding current. At this time, since the actual valve timing is not retarded, it can be seen that the spool valve 30 has caught the foreign matter. This means that the learning prohibition determination has been established. As a result, the determination in step S120 of FIG. 8 becomes YES and the learning condition determination step S121,
S122 and the learning step S123 are jumped. Therefore, the holding current Ih is not learned at point C in FIG. 14 even if the state in which the hydraulic piston 17 of the phase difference adjusting device 40 has collided with the left stopper due to foreign matter biting continues for more than X seconds. , Can prevent mis-learning.

According to the embodiment described above, even if a temporary abnormality occurs in the valve timing adjusting device, learning of the control signal during the abnormality is prohibited and the learning value before the abnormality is held. Therefore, it is possible to exert the same control ability immediately after the abnormality is resolved as before the abnormality occurs. Therefore,
Even if there is a temporary abnormality, the desired valve timing can be surely achieved immediately after its elimination, and as a result,
The engine performance can be fully brought out.

FIG. 15 is a flow chart showing a first modification for the learning prohibition judgment by the learning prohibition judging section 104. In step S140, it is determined whether the target current Id falls between the holding current upper limit value Ihgx and the lower limit value Ihgn. If the difference is between Ihgx and Ihgn, NO in step S140.
After the determination, the learning prohibition signal is set in step S141, and the arithmetic processing is ended. Target current Id is Ih
If it is between gx and Ihgn, after the determination of YES in step S140, step S142.
At, the learning prohibition signal is released.

In the holding current learning when the target current Id deviates from the upper and lower limits of the holding current, it is also effective against erroneous learning to limit the width of update of the learning value instead of prohibiting the learning. is there. FIG. 16 shows a test result in the case of the first modification for the learning prohibition determination described above. Here, the holding current is the upper limit value Ihgx and the lower limit value hg of FIG.
Under the premise that the target current does not exceed n, learning prohibition determination is performed by utilizing that the target current exceeds the upper limit value or the lower limit value.

When the actual valve timing y is feedback-controlled with respect to the change of the target valve timing r, the spool valve 30 bites and locks the foreign matter at the point B, so that the actual valve timing continues to advance. Then, when the point E has passed, the target current Id exceeds the lower limit value Ihgn of the holding current, so that the learning prohibition determination is established. As a result, the hydraulic piston 17 of the phase difference adjusting device 40
After colliding with the left stopper, the actual valve timing becomes steady. After that, since the holding current Ih is not learned at the point C where Xsec has elapsed and the learning condition is satisfied, erroneous learning can be prevented.

FIG. 17 is a flow chart showing a second modification example for the learning prohibition judgment by the learning prohibition judgment unit 104. In step S150, it is determined whether the absolute value of the control deviation e is greater than or equal to the predetermined value ea. If the absolute value of the control deviation e is greater than or equal to the predetermined value ea, after the determination of YES in step S150, in step S151
It is determined whether the value Te of the determination counter is Zsec or more. If Te is less than Zsec, NO is determined in step S151, and the arithmetic processing is ended. Te is Zse
If c or more, YES is determined in step S151, the learning prohibition signal is set in step S152, and the arithmetic processing is ended. In step S150, if the absolute value of the control deviation e is less than the predetermined value ea, N
It is determined to be O, the determination counter is reset to Te = 0, the learning prohibition signal is released, and the arithmetic processing is ended.

FIG. 18 shows a second example for the learning prohibition determination described above.
The test result in the case of a modification is shown. Here, the control deviation e
Since the state in which the absolute value of is maintained at the predetermined value ea or more continues for the predetermined time Zsec or more, it is recognized that the actual valve timing is the valve timing abnormality due to the feedback. This means that the learning prohibition determination is performed based on the determination that there is a possibility that the spool valve foreign matter may be caught.

When the actual valve timing y is feedback-controlled with respect to the change of the target valve timing r and the spool valve 30 bites in and locks the foreign matter at point B, the actual valve timing continues to advance. After that, when the point F has passed, the control deviation e exceeds the predetermined value ea, and the learning prohibition determination is established at point G where this state continues for Zsec. As a result, the actual valve timing becomes steady after the hydraulic piston 17 of the phase difference adjusting device 40 collides with the left stopper. After that, at the point C where Xsec has elapsed and the learning condition is satisfied, the holding current Ih
Since it is never learned, it is possible to prevent erroneous learning. It is desirable that these determination times be Z <X.

FIG. 19 is a flow chart showing a third modification for the learning prohibition judgment by the learning prohibition judgment unit 104. In step S160, it is determined whether the actual valve timing y falls between the upper limit value ygx and the lower limit value ygn of the learnable range. If the actual valve timing y deviates from the upper limit value ygx and the lower limit value ygn of the learnable range, NO in step S160.
After that, in step S161, the learning prohibition signal is set and the arithmetic processing is ended. Actual valve timing y
Is between the upper limit ygx and the lower limit ygn of the learnable range, YES in step S160.
After that, the learning prohibition signal is released.

FIG. 20 shows a third example for the learning prohibition determination described above.
The test result in the case of a modification is shown. Here, it is determined based on the actual valve timing whether the hydraulic piston 17 of the phase difference adjusting device 40 collides with the right stopper.
In this case, since there is a possibility that the spool valve foreign matter may be caught, learning prohibition determination is performed. Whether or not the right side stopper collides is determined in consideration of variations in assembly of the phase difference adjusting device, the sensor, etc., and the actual valve timing y> ygx.
In step 1, it is performed depending on whether or not it is within a certain range near the right side stopper.

When the actual valve timing y is feedback-controlled with respect to the change of the target valve timing r and the spool valve 30 bites in and locks the foreign matter at the point B, the actual valve timing continues to advance. After that, when the point H is passed, the actual valve timing y is y
Since gx is exceeded, the learning prohibition determination is established. As a result, the actual valve timing becomes a steady state after the hydraulic piston 17 of the phase difference adjusting device 40 collides with the right side stopper. Therefore, C when the learning condition is satisfied after Xsec has elapsed
At this point, since the holding current Ih is not learned, erroneous learning can be prevented.

The learning prohibition determinations in the above-described embodiment and each modification may be used alone or in combination. Further, in the learning prohibition determination in the above-described embodiment and each modified example, the case where the hydraulic piston 17 collides with the right side stopper on the advance side due to the foreign matter being caught in the spool valve 30 has been described, but the invention is not limited to this. Even when the piston 17 collides with the left stopper on the retard side, substantially the same effect as described above can be achieved.

Further, in the above-mentioned embodiment and each modification, the example in which the present invention is applied to the valve timing adjusting device for adjusting the opening / closing timing of the intake valve of the internal combustion engine 1 has been described. The present invention may be applied to the valve timing adjusting device that adjusts the opening / closing timing of the exhaust valve or both the intake valve and the exhaust valve of the engine 1.

In the embodiment of the present invention, as shown in FIG. 8, when the actual valve timing becomes constant and the value T of the learning counter becomes Xsec or more, the holding current Ih = Id. However, instead of this, the following learning method may be adopted and implemented. That is, the hydraulic piston 17
Corresponds to a control signal corresponding to a target current to the linear solenoid 64 corresponding to an operating state in which the hydraulic piston 17 starts to move toward the advance side, and corresponds to a target current to the linear solenoid 64 corresponding to an operating state in which the hydraulic piston 17 starts to move toward the retard side. The control signal or the control signal corresponding to the operating state in which the hydraulic piston 17 is held at its actual position may be learned.

In the embodiment described above, learning of the control signal during the occurrence of the abnormality is prohibited, and the learning value before the occurrence of the abnormality is held. Therefore, the learning value is prevented from being updated to the abnormal value, and the valve timing is controlled with the same ability as that before the abnormality occurs after the abnormality is resolved, but the learning value may be returned to the initial value when the abnormality occurs. . As the initial value in this case, it is desirable to use a median value that is set in advance for starting use of the engine. With this configuration, the control deviation is prevented from becoming abnormally large immediately after the abnormality is resolved. Therefore, only a control deviation that is allowable at the start of use of the engine occurs, so that the desired valve timing can be reliably realized with an allowable error. As a result, the engine performance can be sufficiently brought out.

In the above embodiment, the chain drive system is used as the transmission mechanism for rotating the cam shaft in synchronization with the crank shaft, but a belt drive system or a gear drive system may be used. Further, the present invention is not limited to a vehicle, and may be applied to an overhead cam type internal combustion engine of a motorcycle, a ship, or the like. In implementing the present invention, the valve timing adjusting device may be adopted not only in the overhead cam type internal combustion engine but also in the overhead valve type internal combustion engine, and the present invention may be applied thereto.

In implementing the present invention, a pair of flow rate control valves may be adopted instead of the spool valve 30. Further, each step in each flow chart of the above-described embodiment may be realized by a hard logic configuration as a function executing means.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of the present invention applied to a double overhead cam type internal combustion engine.

FIG. 2 is an enlarged cross-sectional view of the phase difference adjusting device shown in FIG.

FIG. 3 is an operation explanatory view of the spool valve shown in FIG.

FIG. 4 is a characteristic diagram showing a relationship between a spool position and an actual valve timing change speed (dy / dt).

FIG. 5 is a characteristic diagram showing a relationship between a linear solenoid current and an actual valve timing change speed (dy / dt), and an enlarged diagram of a portion indicated by a symbol A in the figure.

FIG. 6 is a block diagram showing a functional block of the configuration of the embodiment shown in FIG.

FIG. 7 is a flowchart showing the contents of calculation in the current calculator shown in FIG.

8 is a flowchart showing the contents of holding current learning in the learning unit shown in FIG.

FIG. 9 is a characteristic diagram showing an experimental result regarding the holding current learning process.

FIG. 10 is a characteristic diagram showing test results when a spool valve bites and locks a foreign matter.

FIG. 11 is a characteristic diagram showing test results when the spool valve returns to the normal state after the determination of the foreign matter biting abnormality of the spool valve.

FIG. 12 is a characteristic diagram of the upper limit product and the lower limit product of the product variation of the actual valve timing change speed (dy / dt) with respect to the target current.

FIG. 13 is a flowchart for learning prohibition determination that accompanies determination of foreign matter trapping in the spool valve.

FIG. 14 is a characteristic diagram showing a test result using the determination of foreign matter trapping in the spool valve in the learning inhibition determination.

FIG. 15 is a flowchart showing a first modified example of learning prohibition determination.

FIG. 16 is a characteristic diagram showing test results in the first modified example.

FIG. 17 is a flowchart showing a second modification of learning prohibition determination.

FIG. 18 is a characteristic diagram showing test results in the second modified example.

FIG. 19 is a flowchart showing a third modified example of learning prohibition determination.

FIG. 20 is a characteristic diagram showing test results in the third modified example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank shaft, 3 ... Timing chain, 4 ... Exhaust side cam shaft, 5 ... Intake side cam shaft, 13a, 13b ... Sprocket, 29 ...
..Hydraulic pump, 30 ... Spool valve, 40 ... Phase difference adjusting device, 42 ... Crankshaft position sensor, 44
... cam shaft position sensor, 48 ... microcomputer, 49 ... current control circuit.

─────────────────────────────────────────────────── ─── Continued Front Page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F02D 13/02 F01L 1/34 F01L 13/00 301 F02D 45/00 340

Claims (4)

(57) [Claims] 1. A phase difference adjusting device for adjusting a phase difference between a crankshaft and a camshaft of an internal combustion engine according to an oil pressure, and a control valve for controlling the oil pressure to the phase difference adjusting device according to an opening degree. An opening degree adjusting means for adjusting the opening degree of the control valve; and an actual valve timing detection for detecting an actual valve timing of at least one of an intake valve and an exhaust valve based on a relative rotation angle between the crankshaft and the camshaft. Means, target valve timing setting means for setting a target valve timing of at least one of an intake valve and an exhaust valve according to an operating state of the internal combustion engine, and feedback control so that the actual valve timing matches the target valve timing. A control signal output means for outputting a control signal for controlling the opening degree adjusting means, and the phase difference adjusting device based on the actual valve timing. A learning means for learning a control signal to the opening adjustment means for bringing the phase difference adjustment state, and a valve timing adjustment for adjusting valve imming of at least one of the intake valve and the exhaust valve according to the learning of the learning means. In the device, an abnormality determining means for determining an abnormality of the feedback control, and a prohibiting means for inhibiting learning by the learning means when the abnormality determining means determines the abnormality are provided , and further based on the actual valve timing. Phase difference adjustment
Phase difference adjustment status judgment hand to judge the phase difference adjustment status of the device
A step is provided, and the abnormality determining means determines whether the feedback control is abnormal.
The determination result of the phase difference adjustment state determination means and the
A valve timing adjusting device for an internal combustion engine, which is performed based on a control signal . 2. When the control signal has a value of a predetermined value or more, it is determined that the changing direction of the actual valve timing is a predetermined direction, and when the control signal has a value of the predetermined value or less, A change direction determination unit that determines that the change direction of the actual valve timing is the opposite direction to the predetermined direction is provided, and the abnormality determination unit determines whether the feedback control is abnormal by the predetermined direction by the change direction determination unit. The valve timing adjusting device according to claim 1 , wherein the valve timing adjusting device is performed based on a determination as to a direction or the opposite direction. 3. A valve timing state judging means for judging that the constant state of the actual valve timing continues for a predetermined time, and a control signal judging means for judging that the control signal is within a predetermined range. provided, the abnormality determination means, an abnormality determination of the feedback control, the valve timing control apparatus according to claim 1, characterized in that on the basis of both the determination result of the valve timing state determination unit and the control signal judging unit. 4. Between a crankshaft and a camshaft of an internal combustion engine
A phase difference adjusting device that adjusts the phase difference according to the hydraulic pressure, and a control that controls the hydraulic pressure to the phase difference adjusting device according to the opening degree.
A control valve, an opening adjusting means for adjusting the opening of the control valve, and a suction valve based on a relative rotation angle between the crankshaft and the camshaft.
Actual valve timing of at least one of the air valve and the exhaust valve
To detect the actual valve timing, and to reduce the number of intake valves and exhaust valves depending on the operating state of the internal combustion engine.
Target valve that sets the target valve timing for both
Timing setting means and the actual valve timing to the target valve timing
Control signal for feedback control to match
Control signal output means for outputting a signal to the opening degree adjusting means, and the phase difference adjusting device based on the actual valve timing.
Control to the degree of opening adjusting means for setting a predetermined phase difference adjustment state
A learning means for learning a signal is provided, and the intake valve and the exhaust valve are reduced according to the learning of the learning means.
Valve timing to adjust valve imming on one side
In ring adjuster, abnormality determination means for determining an abnormality of the feedback control
When the abnormality determining means determines the abnormality, the learning
Means for prohibiting learning by means, and the actual valve timing is within a predetermined range.
A means for determining the actual valve timing range is provided to determine whether the feedback control is abnormal.
Constant, the determination result of the real Barubuta timing range determining means
A valve timing adjusting device for an internal combustion engine, which is performed based on