JP3189770B2 - Valve characteristic control 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 characteristic control device for an internal combustion engine that changes the opening / closing characteristics of an intake valve or an exhaust valve by moving a cam whose cam profile changes in the axial direction of a camshaft. More specifically, the present invention relates to an improvement of a device which includes a sensor for detecting the movement position of the cam and reliably changes the position of the cam by feedback control based on the detected position.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine such as a vehicle-mounted engine, the opening and closing characteristics of an intake valve and an exhaust valve are appropriately changed in order to improve output and reduce emission. As a device for changing the valve characteristics in this way, for example, a valve characteristic control device described in Japanese Patent Application Laid-Open No. 4-187807 is known. FIG. 17 shows an outline of the valve characteristic control device described in the publication.

As shown in FIG. 17, a cylinder head 10 of an engine provided with the valve characteristic control device 101 is provided.
An intake passage 103 connected to a combustion chamber (not shown) is provided in 2, and an intake valve 104 is provided in the intake passage 103. The intake passage 103 and the combustion chamber are communicated and shut off based on the opening and closing drive of the intake valve 104.
The opening and closing characteristics of the intake valve 104 are changed by the valve characteristic control device 101.

A valve characteristic control device 101 includes a camshaft 105 provided above a cylinder head 102,
A cam 106 attached to the camshaft 105 and a moving mechanism 107 for moving the cam 106 in the axial direction of the camshaft 105 are provided.

[0005] The rotation of a crankshaft (not shown), which is the output shaft of the engine, is transmitted to the camshaft 105. The cam 106 attached to the camshaft 105 is in contact with the upper end of the intake valve 104. The cam 106 is a camshaft 105
, And can rotate integrally with the camshaft 105. The cam profile of the cam 106 changes continuously in the axial direction of the camshaft 105 as shown in FIG.

The camshaft 105 and the cam 10
6 rotates, the cam 106 causes the intake valve 104 to rotate.
Is driven to open and close. The cam 106 is the camshaft 10
5, the valve opening timing of the intake valve 104 gradually increases, the valve opening time of the intake valve 104 gradually increases, and the valve lift of the intake valve 104 gradually increases. Become larger. or,
The cam 106 moves along the axis of the camshaft 105 with an arrow P
In the direction, the opening timing of the intake valve 104 gradually decreases, the opening time of the intake valve 104 gradually decreases, and the valve lift of the intake valve 104 gradually decreases.

[0007] The valve characteristics of the intake valve 104 are usually changed by reducing the opening time of the intake valve 104 and improving the stability and torque of the engine when the engine is running at a low speed. By reducing the valve lift of 104, the mixed gas is vigorously sucked into the combustion chamber.

In order to improve the output when the engine is running at a high speed, the valve opening time of the intake valve 104 is lengthened and the valve lift of the intake valve 104 is increased so that a large amount of mixed gas is sucked into the combustion chamber. . And so on.

On the other hand, a moving mechanism 107 for moving the cam 106 includes a pushing arm 108 for sandwiching the cam 106 from both sides in the axial direction of the camshaft 105, and a camshaft 1.
There is provided a screw shaft 109 extending in the same direction as 05 and to which the push arm 108 is screwed, and a control motor 110 for rotating the screw shaft 109. In the moving mechanism 107 configured as described above, the screw shaft 109 is controlled by the control motor 110.
Is rotated, the pushing arm 108 moves along the screw shaft 109, and the cam 10 pushed by the pushing arm 108
6 moves in the axial direction of the camshaft 105.

The control motor 110 is driven and controlled by a control device 111. That is, the control device 111 includes a rotation speed sensor 115 for detecting the engine rotation speed,
Detection signals from various sensors 112 for detecting the operating state of the engine are input, and drive control of the control motor 110 is performed based on each of the detection signals. Further, the control device 111 receives a detection signal from a cam position sensor 116 for detecting the movement position of the cam 106, performs feedback control on the control motor 110 based on the detection signal, and outputs a cam signal corresponding to the operating state of the engine. The 106 optimal cam profiles are selected.

[0011]

The sensor used for the cam position sensor 116 includes, for example, a coil for generating an induced electromotive force corresponding to the position of the cam.
A so-called gap sensor that outputs the induced electromotive force as a detection signal is conceivable. However, since the gap sensor has a narrow distance range in which an accurate movement position can be detected, it is difficult to accurately detect the movement position of the cam over the entire movement range of the cam.

Further, even when an optical sensor or the like is used in place of the gap sensor, in an environment such as an engine where vibration and dirt are severe, the detection accuracy is reduced due to the vibration and dirt, and the detection is performed. Naturally, the cam position is also low in reliability.

[0013] In any case, if the position of the cam cannot be accurately detected by the sensors, the setting of the optimum cam profile described above will not be obvious.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to control valve characteristics of an internal combustion engine capable of accurately detecting a moving position of a cam and performing more accurate cam position control. It is to provide a device.

[0015]

In order to achieve the above object, according to the first aspect of the present invention, the cam extends in the axial direction of the camshaft with a locus different from the locus of the cam moved by the moving means. A detection unit, and a pulse generation unit that generates a pulse in response to the passage of the detection unit along with the rotation of the camshaft, wherein a pulse generated from the pulse generation unit and corresponding to the detection unit is generated. And the criteria
Pulse, and whether this reference pulse is generated
The movement position of the cam in the axial direction of the camshaft is detected based on the time until the generation of a pulse corresponding to the detected portion .

According to this configuration, since the detected portion extends with a trajectory different from the movement trajectory of the cam by the moving means, when the cam moves in the axial direction of the camshaft by the moving means, a pulse from the pulse generating means is generated. The timing of occurrence changes. Therefore, by monitoring the change in the pulse generation timing, it becomes possible to accurately detect the cam movement position in the axial direction of the camshaft. Then, even when the cam position is feedback-controlled to set the optimal cam profile according to the engine operating state,
More accurate cam position information can be taken into the feedback system.

According to the second aspect of the present invention, in particular, the first and second detected portions extending in different directions from each other in the axial direction of the camshaft, and the first and second detected portions accompanying the rotation of the camshaft.
And a pulse generating means for generating a pulse in response to the passage of the second part to be detected, prior to the said pulse generating means
The pulse is generated from the pulse generation corresponding to each of the detected parts.
The movement position of the cam in the camshaft axis direction is detected based on the time until the occurrence of the cam.

According to this configuration, when the cam moves in the axial direction of the camshaft by the moving means, the generation timing of the pulse generated from the pulse generation means changes in response to the first and second detected parts. I do. Since the first and second detected parts extend in different modes, the amount of change in the generation timing of the pulse corresponding to the first detected part and the change in the generation timing of the pulse corresponding to the second detected part are different. It will be different from the quantity. Therefore, it is possible to monitor a change in the generation timing of the pulse from the change in time from the generation of the pulse corresponding to the first detected part to the generation of the pulse corresponding to the second detected part. . Therefore, the movement position of the cam in the direction of the camshaft axis detected by monitoring the amount of change in the generation timing of these pulses becomes more accurate.

According to a third aspect of the present invention, in the second aspect, one of the first and second detected portions is
The cam has the same locus as the movement locus of the cam moved by the moving means, and extends in the axial direction of the camshaft.

According to this configuration, one of the first and second detected portions extends with a locus different from the cam locus of the cam by the moving means. The generation timing of the pulse generated from the pulse generation means changes in response to one of the detected parts. Since the other of the first and second detected portions extends along the same locus as the movement locus of the cam by the moving means, even if the cam is moved by the moving means, Does not change in response to the detected part. Therefore, it is possible to monitor the amount of change in the generation timing of the pulse generated in response to one of the detected parts with reference to the pulse generated from the pulse generating means in response to the other detected part. Become. Therefore, the moving position of the cam in the axial direction of the camshaft can be accurately detected without providing a detected portion and a pulse generating means for generating a reference pulse on the output side or the like of the internal combustion engine. Become like
Then, even when the cam position is feedback-controlled to set an optimal cam profile according to the engine operating state, more accurate cam position information can be taken into the feedback system.

According to the fourth aspect of the present invention, the second or third aspect is provided.
In the described invention, the first and second detected parts are:
The camshaft is provided so as to be symmetric with respect to the axis of the camshaft.

According to this configuration, since the detection widths of the first and second detected portions as viewed from the pulse generating means are always equal, the pulse width of the pulse generated by the pulse generating means corresponding to the detected portions is always equal. The pulse widths are also always equal, and the occurrence timing can be detected more accurately.

According to the fifth aspect of the invention, in particular, the first detection portion extending in the axial direction of the camshaft having a trajectory different from the movement trajectory of the cam moved by the moving means,
A second detection portion extending in the axial direction of the camshaft having the same trajectory as the movement trajectory of the cam moved by the moving means, and the first and second detection portions associated with the rotation of the camshaft; And a pulse generating means for generating a pulse in response to the passage of the detected part, wherein a pulse is generated before the pulse corresponding to the second detected part is generated from the pulse generating means.
The movement position of the cam in the camshaft axis direction is detected based on the time until the generation of the pulse corresponding to the first detected portion, and the position of the cam corresponding to the second detected portion is detected.
Pulse that is the reference for the pulse generated by the
From the generation of this reference pulse.
2 based on the time until the pulse corresponding to the detected part
Then, the amount of change in the rotational phase of the camshaft relative to the engine output shaft is detected.

According to this configuration, the first detected portion extends with a locus different from the moving locus of the cam by the moving means. Therefore, when the moving means moves the cam in the axial direction of the camshaft, the first detected portion is moved to the first position. The pulse generation timing generated by the pulse generation means changes in response to the detected portion. Therefore, by monitoring the change in the pulse generation timing, it becomes possible to accurately detect the cam movement position in the axial direction of the camshaft. Then, even when the cam position is feedback-controlled to set an optimal cam profile according to the engine operating state, more accurate cam position information can be taken into the feedback system. Further, since the second detected portion extends with the same locus as the movement locus of the cam by the moving means, the pulse generated from the pulse generating means in response to the second detected portion is moved by the moving means. The generation timing does not change depending on the movement of the cam in step (1), and the generation timing changes only by changing the rotation phase of the camshaft by the phase changing means. Therefore, by monitoring the change in the pulse generation timing, it becomes possible to accurately detect the amount of change in the rotational phase of the camshaft relative to the engine output shaft. Then, even when the camshaft rotation phase is feedback-controlled to set the optimal camshaft rotation phase according to the engine operating state, more accurate camshaft rotation phase information can be taken into the feedback system. Become. In the invention according to claim 6, in particular, the moving means
With a trajectory different from the trajectory of the cam
A first detected portion extending in the axial direction of the
Same as the movement locus of the cam moved by the moving means.
A second extending in the axial direction of the camshaft with a locus;
Detected portions, and those detected by the rotation of the camshaft.
Generates a pulse in response to passage of the first and second detected parts
Pulse generating means,
From the generation of the pulse corresponding to the second detected part,
1 based on the time until the pulse corresponding to the detected part
Position of the cam in the axial direction of the camshaft.
Position of the camshaft with respect to the engine output shaft.
The relative rotation phase change amount is detected. With the same configuration
If so, the first detected portion is the movement locus of the cam by the moving means.
Because it extends with a trajectory different from the
Moves in a spiral path along the camshaft axis
Then, in response to the first detected part, the pulse generating means
The generation timing of the generated pulse changes. others
Monitoring the change in the pulse generation timing
The position of the cam in the axial direction of the camshaft.
Can be detected. And the cam position
Feedback control to optimize the engine operating condition.
Higher accuracy, even when setting cam profiles
Cam position information into the feedback system.
I will be able to. In addition, the accurate detection of the
Camshaft relative to the engine output shaft based on the
Can accurately detect the relative rotation phase change
Become like Then, the camshaft rotation phase is
Optimal camshaft according to engine operating state
Even when setting the
The rotational phase information of the motor shaft into the feedback system
Will be able to do it.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment in which a valve characteristic control device according to the present invention is applied to an in-line four-cylinder in-vehicle engine will be described with reference to FIGS.

As shown in FIG. 1, an engine 11 includes a cylinder block 1 provided with a reciprocating piston 12.
3, 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 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 performed by the connecting rod 16 of the crankshaft 1.
5 rotations. A combustion chamber 17 is provided above the piston 12, and the combustion chamber 1
An intake passage 18 and an exhaust passage 19 are connected to 7. 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 camshaft 22 and an exhaust camshaft 23 in parallel. The intake camshaft 22 is rotatable and movable in the axial direction, and the exhaust camshaft 23 is rotatable. At one end of the intake camshaft 22, a valve timing adjusting mechanism 24 having a pulley 24a is provided, and at the other end, a moving mechanism 22a for moving the intake camshaft 22 in the axial direction is provided. . A pulley 25 is attached to one end of the exhaust camshaft 23. The pulley 25 and the pulley 24 a of the valve timing adjustment mechanism 24 are connected to a pulley 15 a attached to the crankshaft 15 via a timing belt 26. The rotation of the crankshaft 15 is controlled by the timing belt 2.
By being transmitted to the intake and exhaust camshafts 22 and 23 through 6, the intake and exhaust camshafts 22 and 23 rotate.

The intake camshaft 22 and the exhaust camshaft 23 are provided with an intake cam 27 abutting on the upper end of the intake valve 20 and an exhaust cam 28 abutting on the upper end of the exhaust valve 21, respectively. When the intake camshaft 22 and the exhaust camshaft 23 rotate, the intake cam 27 and the exhaust cam 28 open and close the intake valve 20 and the exhaust valve 21.

Here, the cam profile of the exhaust cam 28 is constant with respect to the axial direction of the exhaust camshaft 23, but the cam profile of the intake cam 27 continuously changes in the axial direction of the intake camshaft 22. are doing.
When the intake camshaft 22 moves in the direction of the arrow A, the valve opening time of the intake cam 27 gradually increases, and the valve lift gradually increases. When the intake camshaft 22 moves in a direction opposite to the above, the valve opening time of the intake cam 27 gradually decreases, and the valve lift gradually decreases. Therefore, by moving the intake camshaft 22 in the axial direction, the valve opening time and the valve lift of the intake valve 27 can be adjusted.

The intake camshaft 22 is moved in the direction opposite to the arrow A when the engine 11 is running at a low speed, and is moved in the direction shown by the arrow A when the engine is running at a high speed. This reduces the valve opening time of the intake valve 27 and reduces the valve lift when the engine 11 rotates at a low speed, thereby reducing the combustion chamber 17
This is because the mixed gas is vigorously sucked, the valve opening time of the intake valve 27 is increased and the valve lift amount is increased at the time of high engine rotation to improve the efficiency of sucking the mixed gas into the combustion chamber 17.

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

As shown in the figure, the moving mechanism 22a comprises a cylindrical cylinder tube 31 and a cylinder tube 3
1 and a cylinder tube 3
1 and a pair of end covers 33 provided so as to close the openings at both ends. The intake camshaft 22 penetrating one end cover 33 is connected to the piston 32. In the cylinder tube 31, a first pressure chamber 31a and a second pressure chamber 31b are formed by a piston 32.
Is divided into A first supply / discharge passage 34 and a second supply / discharge passage 35 formed in a pair of end covers 33 are connected to the first pressure chamber 31a and the second pressure chamber 31b, respectively.

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

The first supply / discharge passage 34 and the second supply / discharge passage 35 are provided with a first oil control valve (OCV).
It is connected to 36. A supply passage 37 and a discharge passage 38 are connected to the first OCV 36. The supply passage 37 is connected to the oil pan 13a via an oil pump P driven by rotation of the crankshaft 15, and the discharge passage 38 is directly connected to the oil pan 13a.

The first OCV 36 has a casing 39, and the casing 39 has a first and a second supply / discharge port 4.
0, 41; first and second discharge ports 42, 43;
A supply port 44 is provided. The first and second supply / discharge passages 34, 35 are connected to the first and second supply / discharge ports 40, 41, respectively. Further, the supply passage 37 is connected to the supply port 44, and the discharge passage 38 is connected to the first and second discharge ports 42 and 43. A spool 48 having four valve portions 45 in the casing 39 and urged in opposite directions by a coil spring 46 and an electromagnetic solenoid 47, respectively.
Is provided.

When the electromagnetic solenoid 47 is in the demagnetized state, the spool 48 is disposed at one end (right side in FIG. 2) of the casing 39 by the elastic force of the coil spring 46, and the first supply / discharge port 40 and the first Discharge port 42
And the second supply / discharge port 42 communicates with the supply port 44. In this state, the oil in the oil pan 13a is supplied to the second pressure chamber 31b via the supply passage 37, the first OCV 36, and the second supply / discharge passage 35. Also, the oil in the first pressure chamber 31a is discharged from the first supply / discharge passage 34,
The oil is returned to the oil pan 13a via the first OCV 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 is disposed on the other end side (left side in FIG. 2) of the casing 39 against the elastic force of the coil spring 46, and the second supply / discharge port is provided. 41 is a second discharge port 43
The first supply / discharge port 40 communicates with the supply port 44. In this state, the oil in the oil pan 13a is supplied to the supply passage 37, the first OCV 36, and the first supply / discharge passage 3
4 to the first pressure chamber 31a. The oil in the second pressure chamber 31b is discharged from the second supply / discharge passage 35,
The oil pan 13 via the OCV 36 and the discharge passage 38
It is returned in a. 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 and second supply / discharge ports 40 and 41 are closed,
The movement of oil through the supply / discharge ports 40 and 41 is prohibited. In this state, the first and second pressure chambers 31
Oil is not supplied to and discharged from the first and second pressure chambers 31a and 31b, and the first and second pressure chambers 31a and 31b are filled with oil so that the piston 32 and the intake camshaft 22 are fixed. .

Next, the valve timing adjusting mechanism 24 for adjusting the opening / closing timing of the intake valve 20 will be described in detail with reference to FIG. As shown in the figure,
The valve timing control mechanism 24 includes a pulley 24a,
The pulley 24a includes a cylindrical portion 51 through which the intake camshaft 22 passes, 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 pulley 24a is rotatably supported by the bearing portion 14a of the cylinder head 14. The intake camshaft 22 penetrates the cylindrical portion 51 so as to be movable in the axial direction.

The pulley 24a has an intake camshaft 2
A cover 54 provided to cover the end of the second 2 is fixed by bolts 55 and pins 56. At a position corresponding to the end of the intake camshaft 22 on the inner peripheral surface of the cover 54, a plurality of internal teeth 57 are provided along the circumferential direction. On the other hand, an inner cap 60 is fixed to the tip of the intake camshaft 22 by a hollow bolt 58 and a pin 59. A plurality of external teeth 61 are provided on the outer peripheral surface of the inner cap 60 along the circumferential direction, and each external tooth 61 faces each internal tooth 57 of the cover 54. Between each external tooth 61 and each internal tooth 57, a ring gear 62 formed in a cylindrical shape is provided.
The intake camshaft 22 is provided so as to be movable in the axial direction. On the outer peripheral surface of the ring gear 62, the internal teeth 5 are provided.
A bevel tooth 63 meshing with the outer gear 61 is provided on the inner peripheral surface of the ring gear 62. The spur teeth 64 extend linearly in the axial direction of the intake camshaft 22.

Accordingly, in such a valve timing adjusting mechanism 24, when the crankshaft 15 is rotated by driving the engine and the rotation is transmitted to the pulley 24a via the timing belt 26, the pulley 24a and the intake camshaft 22 are integrated. To rotate. As described above, the intake valve 20 (FIG. 1) is driven to open and close as the intake camshaft 22 rotates.

When the ring gear 62 moves toward the pulley 24a (to the right in the drawing), the relative rotation phase between the pulley 24a and the intake camshaft 22 changes due to the action of the beveled teeth 63 on the ring gear 62, and the intake camshaft 22 changes. Reference numeral 22 is controlled so as to retard the crankshaft 15. That is, at this time, the opening / closing timing of the intake valve 20 is delayed. When the ring gear 62 moves toward the cover 54 (to the left in the drawing), the ring gear 6
2, the relative rotation phase between the pulley 24a and the intake camshaft 22 changes in the opposite direction to that described above, and the intake camshaft 22 is controlled to advance to the crankshaft 15 side. Become. That is, at this time, the opening / closing timing of the intake valve 20 is advanced.

The intake valve 20 is normally connected to the engine 11
The opening / closing timing is delayed when the engine is running at a low speed, and the opening / closing timing is advanced when the engine 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 suction of the mixed gas into the combustion chamber 17 when the engine 11 is running at a high speed.

Next, a structure of the valve timing adjusting mechanism 24 for hydraulically controlling the movement of the ring gear 62 will be described. The inside of the cover 54 is partitioned by a ring gear 62 into a retard side hydraulic chamber 65 and an advance side hydraulic chamber 66. Inside the intake camshaft 22, a retard control oil passage 67 connected to the retard control hydraulic chamber 65 and the advance control hydraulic chamber 66, respectively.
And the advance angle control oil passage 68 passes through. The retard control oil passage 67 passes through the inside of the hollow bolt 58 and passes through the retard hydraulic chamber 6.
5 and through the interior of the cylinder head 14 to a second oil control valve (OCV) 69. The advance control oil passage 68 is connected to the pulley 24a.
Of the second OCV 6 through the inside of the cylinder head 14 while communicating with the advance-side hydraulic chamber 66 through the cylindrical portion 51 of the second OCV 6.
9 is connected. On the other hand, a supply passage 70 and a discharge passage 71 are connected to the second OCV 69. And
The supply passage 70 is connected to the oil pan 13a via the oil pump P, and the discharge passage 71 is directly connected to the oil pan 13a. Therefore, the oil pump P
Is designed to send oil from the oil pan 13a to the two supply passages 37 and 70.

The second OCV 69 is the first OCV 36
, The casing 39, the first and second supply / discharge ports 40, 41, the first and second discharge ports 42,
43, a supply port 44, a coil spring 46, an electromagnetic solenoid 47, and a spool 48. The first and second supply / discharge ports 40 and 41 are connected to a retard control oil passage 67 and an advance control oil passage 68, respectively. The supply port 44 is connected to a supply passage 70, and the first and second discharge ports 42 and 43 are connected to a discharge passage 71.

Accordingly, when the electromagnetic solenoid 47 is in the demagnetized state, the spool 48 is disposed at one end (the right side in FIG. 3) of the casing 39 by the elastic force of the coil spring 46, and the first supply / discharge port 40 and the first Discharge port 42
And the second supply / discharge port 41 communicates with the supply port 44. In this state, the oil in the oil pan 13 a is supplied to the advance hydraulic chamber 66 of the valve timing adjustment mechanism 24 via the supply passage 70, the second OCV 69, and the advance control oil passage 68. The oil in the retard side hydraulic chamber 65 of the valve timing adjustment mechanism 24 is returned to the oil pan 13a via the retard control oil passage 67, the second OCV 69, and the discharge passage 71. As a result, the ring gear 62 is moved toward the retard hydraulic chamber 65, and the opening / closing timing of the intake valve 20 is advanced as described above.

On the other hand, when the electromagnetic solenoid 47 is excited, the spool 48 is disposed on the other end side (left side in FIG. 3) of the casing 39 against the elastic force of the coil spring 46, and the second supply / discharge port is provided. 41 is a second discharge port 43
The first supply / discharge port 40 communicates with the supply port 44. In this state, the oil in the oil pan 13a is supplied to the retard hydraulic pressure chamber 65 of the valve timing adjustment mechanism 24 via the supply passage 70, the second OCV 69, and the retard control oil passage 67. The oil in the advance-side hydraulic chamber 66 of the valve timing adjustment mechanism 24 is returned to the oil pan 13a via the advance control oil passage 68, the second OCV 69, and the discharge passage 71. As a result, the ring gear 62 is moved toward the advance hydraulic chamber 66, and the opening and closing timing of the intake valve 20 is delayed as described above.

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 and second supply / discharge ports 40 and 41 are closed,
The movement of oil through the supply / discharge ports 40 and 41 is prohibited. In this state, the retard side and advance side hydraulic chambers 6
The oil is not supplied to and discharged from the hydraulic chambers 5 and 66, and the oil is filled and held in the hydraulic chambers 65 and 66, so that the ring gear 62 is fixed. As a result, the opening and closing timing of the intake valve 20 is maintained at the state when the ring gear 62 is fixed.

Next, the moving position of the intake cam 27 in the axial direction of the intake camshaft 22 and the crankshaft 1
The structure for detecting the amount of change in the relative rotation phase of the intake camshaft 22 with respect to the intake camshaft 22 will be described.

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 72 made of a magnetic material is provided to protrude, and a crank-side electromagnetic pickup 73 is provided near an end of the crankshaft 15. On the outer peripheral surface of the intake camshaft 22 at the end opposite to the valve timing adjusting mechanism 24, a pair of reference detected parts 74 and one movement amount detected part 75, also made of a magnetic material, are provided. A cam-side electromagnetic pickup 76 is provided near the end of the intake camshaft 22.

The above-mentioned pair of crank-side detected parts 72 is shown in FIG.
As shown in (a) and (b), the crank-side detected portions 72 extend linearly in the axial direction of the crankshaft 15.
Is 180 ° with respect to the axis of the crankshaft 15. Then, when the crankshaft 15 rotates, the pair of crank-side detected portions 72
Pass in the rotation direction of the crankshaft 15 with respect to the crank-side electromagnetic pickup 73. When the crank-side detected part 72 and the crank-side electromagnetic pickup 73 pass each other, a current is induced in the crank-side electromagnetic pickup 73, and this is output from the pickup 73 as a pulse signal.

As shown in FIGS. 5 (a) and 5 (b), the pair of reference detected parts 74 extend linearly in the axial direction of the intake camshaft 22. The angular interval around the axis of the intake camshaft 22 is 180 °. On the outer peripheral surface of the intake camshaft 22, a movement detection part 75 is provided at a position corresponding to between the pair of reference detection parts 74, and the movement detection part 75 is provided on the intake camshaft 22. It extends spirally in the axial direction. When the intake camshaft 22 rotates, the pair of reference detected parts 74 and one moving amount detected part 75 pass by the cam side electromagnetic pickup 76 in the rotation direction of the intake camshaft 22. Cam-side electromagnetic pickup 76 and reference portion 7 for reference and movement amount
4 and 75, the cam-side electromagnetic pickup 76
, A current is induced, which is output from the pickup 76 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 and second OCVs
The drive of 36 and 69 is controlled through an electronic control unit (hereinafter referred to as “ECU”) 81, and the opening / closing characteristics of the intake valve 20 are changed by the control. This ECU 81
It is configured as a theoretical operation circuit including a ROM 82, a CPU 83, a RAM 84, a backup RAM 85, and the like.

Here, the ROM 82 is a memory for storing various control programs, maps referred to when the various control programs are executed, and the like. CPU83 is RO
The desired arithmetic processing is executed based on the various control programs stored in M82. The RAM 84 stores the CPU 8
3 is a memory for temporarily storing the result of the calculation in step 3, data input from each sensor, and the like.
Is a nonvolatile memory for storing data to be stored when the engine 11 is stopped. And the ROM 82 and the CPU
The 83, the RAM 84, and the backup RAM 85 are connected to each other via a bus 86, and are also connected to an external input circuit 87 and an external output circuit 88.

The external input circuit 87 includes various sensors for detecting the operating state of the engine 11, such as a rotation speed sensor, an intake pressure sensor, and a throttle sensor (not shown), the crank-side electromagnetic pickup 73 and the cam-side electromagnetic pickup 76. Is connected. The first OCV 36 and the second OCV 69 are connected to the external output circuit 88.

In this embodiment, the ECU 8 having such a configuration is used.
Through 1, valve characteristic control of the intake valve 20 is performed. That is, the ECU 81 controls the drive of the second OCV 69 based on detection signals from various sensors (not shown) for detecting the operation state of the engine 11, and the opening and closing timing of the intake valve 20 becomes suitable for the operation state of the engine 11. The valve timing adjusting mechanism 24 is operated. or,
The ECU 81 controls the driving of the first OCV 36 based on the detection signals from the various sensors, and controls the moving mechanism 22 a so that the opening time of the intake valve 20 and the valve lift amount are values suitable for the operating state of the engine 11. Activate.

On the other hand, the ECU 81 inputs pulse signals from the crank-side electromagnetic pickup 73 and the cam-side electromagnetic pickup 76. In other words, when the crankshaft 15 is rotating, the crank-side electromagnetic pickup 73 generates pulses P1 at equal intervals corresponding to the pair of reference detected parts 72, as shown by the waveform X1 in FIG.
When the intake camshaft 22 is rotating, the cam-side electromagnetic pickup 76 outputs a pulse P2 corresponding to the pair of reference detected portions 74 as indicated by a waveform X2.
And a pulse P3 corresponding to one moving amount detected portion 75
Occurs.

Now, the cam-side electromagnetic pickup 76 has the waveform X
2, when the pulses P2 and P3 are generated, the intake camshaft 2
Under the condition that the relative rotation phase of No. 2 is not changed, when the intake camshaft 22 moves along the axis, for example, in the direction of arrow B in FIG. Lus P in the mode shown by
2 and P3. In such a change from the waveform X2 to the waveform X3, the generation timing of the pulse P2 is not changed, and only the generation timing of the pulse P3 is changed.

The ECU 81 determines the amount of change in the generation timing of the pulse P3, that is, from the reference pulse P2 to the pulse P3.
Based on the amount of change in the time t1 until the intake camshaft 2
The movement position (movement amount) in the direction of the axis 2 is detected. The detected position of the intake camshaft 22 in the axial direction is more accurate than the conventional case where the position of the intake camshaft in the axial direction is directly detected by a gap sensor or the like. Then, the ECU 81 performs feedback control on the first OCV 36 based on the detected moving position of the intake camshaft 22 in the axial direction, and accurately moves the intake camshaft 22 to a position corresponding to a desired cam profile. Perform a position change.

The cam-side electromagnetic pickup 76 has the waveform X
When the pulses P2 and P3 are generated in the manner shown in FIG. 2, under the condition that the intake camshaft 22 does not move in the axial direction, the valve timing adjustment mechanism 24 described above is used.
When the relative rotation phase of the intake camshaft 22 with respect to the crankshaft 15 is changed, for example, to the advance side (the direction of arrow C in FIG. 5) by the operation of
Generates pulses P2 and P3 in the manner shown by waveform X4 in FIG. In such a change from the waveform X2 to the waveform X4, all the generation timings of the pulses P2 and P3 are uniformly changed in a phase-shifted manner.

The ECU 81 determines the amount of change in the generation timing of the pulse P2, that is, from the reference pulse P1 to the pulse P2.
Based on the amount of change in the time t2 up to the crankshaft 1
5, the amount of change in the relative rotational phase of the intake camshaft 22 with respect to 5. The crankshaft 15 thus detected
ECU 81 performs feedback control on second OCV 69 based on the amount of change in the relative rotational phase of intake camshaft 22 with respect to
Of the relative rotational phase of.

It should be noted that even when the movement of the intake camshaft 22 in the axial direction by the moving mechanism 22a and the change of the rotation phase of the intake camshaft 22 by the valve timing adjusting mechanism 24 are simultaneously performed, the same as described above is obtained. Needless to say, the intake camshaft 22 can be moved in the axial direction and the rotation phase of the intake camshaft 22 can be accurately changed.

As described in detail above, according to the present embodiment, the following effects can be obtained. When the intake cam 27 and the intake camshaft 22 move in the axial direction of the shaft 22, the generation timing of the pulse P <b> 3 generated when the cam-side electromagnetic pickup 76 detects the movement amount detection target 75 changes. Then, based on the amount of change in the generation timing of the pulse P3, that is, the amount of change in the time t1 from the reference pulse P2 to the pulse P3 generated when the cam-side electromagnetic pickup 76 detects the detected reference portion 74, The movement positions of the cam 27 and the intake camshaft 22 are detected. Therefore, the moving positions of the intake cam 27 and the intake camshaft 22 can be detected more accurately than in the conventional case where the moving position of the intake camshaft in the axial direction is directly detected by the gap sensor or the like. . Therefore, when the cam position is feedback-controlled to set an optimal cam profile according to the operating state of the engine, more accurate cam position information can be taken into the feedback system.

When the relative rotation phase of the intake camshaft 22 with respect to the crankshaft 15 is changed, the generation timing of the pulse P2 generated when the cam-side electromagnetic pickup 76 detects the detected reference portion 74 changes.
Therefore, the change amount of the generation timing of the pulse P2, that is, the crank-side electromagnetic pickup 73 is
2, the amount of change in the relative rotational phase of the intake camshaft 22 with respect to the crankshaft 15 can also be accurately detected based on the amount of change in the time t2 from the reference pulse P1 generated when detecting the pulse No. 2 to the pulse P2. . For this reason, when the rotational phase of the intake camshaft 22 is feedback-controlled to set the optimal valve opening / closing timing according to the operating state of the engine, more accurate rotational phase information of the intake camshaft 22 is transmitted to the feedback system. Be able to capture.

Unlike the conventional device which directly detects the position of the intake camshaft in the axial direction by a gap sensor or the like, in the present embodiment, the reference and displacement detection portions which rotate with the intake camshaft 22 are used. The configuration is such that the cam-side electromagnetic pickup 76 only detects 74 and 75. Therefore, as compared with the case where a gap sensor or the like is provided in the engine 11, the mounting space can be reduced, and the mounting performance can be improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the valve timing adjustment mechanism 24 of the first embodiment is used.
Instead, a valve timing adjustment mechanism 91 of a type that performs both the axial movement of the intake camshaft 22 and the change of the rotational phase is employed. That is, in the present embodiment, the valve timing adjusting mechanism 91 also has a role of moving the intake camshaft 22 in the axial direction.
In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description is omitted.

As shown in FIG. 8, in the valve timing adjusting mechanism 91, the ring gear 62 is directly fixed to the intake shaft 22 by the hollow bolt 58 and the pin 59.
Accordingly, when oil is supplied to the retard hydraulic chamber 65 or the advance hydraulic chamber 66 during the operation of the valve timing adjusting mechanism 91, the oil gear pressure causes the ring gear 62 and the intake camshaft 22 to rotate. It moves integrally in the axial direction. At this time, the intake camshaft 22
Are formed with the bevel 63 formed on the ring gear 62 and the cover 54.
Meshing with the internal teeth 57 of the crankshaft 15
The relative rotational phase with respect to FIG. 1 is changed. As a result, the intake camshaft 22 rotates about the coaxial line while moving in the axial direction, and the intake cam 27 moves along a spiral trajectory in the axial direction of the intake camshaft 22. ing.

In the demagnetized state of the electromagnetic solenoid 47 in the second OCV 69, the advance side pressure chamber 66
Is supplied to the intake camshaft 22 and the intake cam 2
7 is moved in the direction of arrow A1. In this state,
The opening / closing timing of the intake valve 20 is advanced, the valve opening time of the intake valve 20 is short, and the valve lift is reduced. When the electromagnetic solenoid 47 of the second OCV 69 is excited, oil is supplied to the retard pressure chamber 65 and oil is discharged from the advance pressure chamber 66 as shown in FIG. Shaft 22
And the intake cam 27 is moved in the direction of arrow A2. In this state, the opening / closing timing of the intake valve 20 is delayed, the valve opening time of the intake cam 27 is long, and the valve lift is increased.

On the other hand, in the present embodiment, as shown in FIG. 10, the intake camshaft 22 is provided with one reference detection part 92 and a movement detection part 93 made of a magnetic material. Crank-side detected part 7 as in the first embodiment
2 and the arrangement of the crank side electromagnetic pickup 73 are omitted. The reference detected portion 92 extends spirally along the movement trajectory of the intake cam 27 due to the operation of the valve timing adjustment mechanism 91, and the movement detected portion 93 extends linearly in the axial direction of the intake camshaft 22. Extends to.

When the reference detected portion 92 and the displacement detected portion 93 are provided on the intake camshaft 22, the cam-side electromagnetic pickup 76 has a waveform X5 shown in FIG. As shown, pulses P2 and P3 corresponding to the reference portions 92 and 93 are output.

Now, the cam-side electromagnetic pickup 76 has the waveform X
When the pulses P2 and P3 are generated in the mode shown in FIG. 5, when the intake camshaft 22 moves along the axis, for example, in the direction of arrow B in FIG. 76
Causes the pulses P2 and P3 to be generated in the manner shown by the waveform X6. In such a change from the waveform X5 to the waveform X6, the generation timing of the pulse P2 is not changed, and only the generation timing of the pulse P3 is changed. This is because the reference detection portion 92 is provided so as to extend along the movement locus of the intake cam 27 when the intake camshaft 22 is moved in the axial direction by the valve timing adjustment mechanism 91.

On the other hand, the ECU 81 detects the axial movement position of the intake camshaft 22 based on the amount of change in the generation timing of the pulse P3, that is, the amount of change in the time t3 from the reference pulse P2 to the pulse P3. . Further, with the movement of the intake camshaft 22 in the axial direction, the relative rotation phase of the intake camshaft 22 with respect to the crankshaft 15 is changed. Therefore, the ECU 81 determines the position of the intake camshaft 22 based on the axial movement position of the intake camshaft 22. The amount of change in the relative rotation phase is detected. The amount of change in the axial movement position and the relative rotational phase of the intake camshaft 22 detected in this manner is an accurate value as in the first embodiment.

Then, the ECU 81 performs feedback control on the second OCV 69 based on the detected movement position of the intake camshaft 22 in the axial direction and the amount of change in the relative rotational phase. An accurate position change to a position corresponding to the cam profile and an accurate relative rotation phase change to a rotation angle corresponding to a desired valve opening / closing timing are performed.

As described in detail above, according to this embodiment, the following effects can be obtained. When the intake camshaft 22 moves in the axial direction due to the operation of the valve timing adjusting mechanism 91, the timing of generating the pulse P3 generated when the cam-side electromagnetic pickup 76 detects the movement amount detection target 93 changes. Then, based on the amount of change in the generation timing of the pulse P3, that is, the amount of change in the time t3 from the pulse P2 generated when the cam-side electromagnetic pickup 76 detects the detected reference portion 92 to the pulse P3, the intake cam 27 is determined. And the movement position of the intake camshaft 22 are detected. Therefore, also in the present embodiment, the intake cam 27 and the intake camshaft 22
Can be accurately detected. Therefore, when the cam position is feedback-controlled to set an optimal cam profile according to the operating state of the engine, more accurate cam position information can be taken into the feedback system.

The amount of change in the relative rotational phase of the intake camshaft 22 with respect to the crankshaft 15 is also detected based on the axial movement positions of the intake cam 27 and the intake camshaft 22 accurately detected as described above. Therefore, the amount of change in the rotation phase of the intake cam 27 and the intake camshaft 22 can also be accurately detected. For this reason, when the rotational phase of the intake camshaft 22 is feedback-controlled to set the optimal valve opening / closing timing according to the operating state of the engine, more accurate rotational phase information of the intake camshaft 22 is transmitted to the feedback system. Be able to capture.

Also in the present embodiment, the reference and displacement detection portions 9 which rotate with the intake camshaft 22
Since the configuration is such that the cams 2 and 93 are only detected by the cam-side electromagnetic pickup 76, the mounting space can be reduced, and the mounting performance can be improved.

The reference detecting portion 92 extends spirally along the movement locus of the intake cam 27 when the intake camshaft 22 is moved in the axial direction by the valve timing adjusting mechanism 91. Therefore, the generation timing of the pulse P2 when the cam-side electromagnetic pickup 76 detects the reference detected portion 92 does not change depending on the axial movement of the intake camshaft 22. Therefore, the amount of change in the generation timing of the pulse P3 based on the pulse P2, that is, the pulse P2
The time t3 from 2 to the pulse P3 can be obtained. As a result, the provision of the crank-side detected portion 72 and the crank-side electromagnetic pickup 73 as in the first embodiment for generating the reference pulse can be omitted.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the intake cam 27 extends in the axial direction of the intake camshaft 22.
Only the structure for detecting the movement position of the second embodiment is different from that of the second embodiment. Therefore, in the present embodiment, detailed description of the same portions as the other second embodiment will be omitted.

As shown in FIG. 12, in the present embodiment, instead of providing the intake camshaft 22 with one movement amount detection portion 93 as in the second embodiment, a pair of movement amount The detection target portion 93a is provided. An angular interval between the moving amount detection portions 93a around the axis of the intake camshaft 22 is 180 °. On the outer circumferential surface of the intake camshaft 22 located between the pair of movement amount detection portions 93a, a reference detection portion 92 made of a magnetic material is provided at an intermediate position in the circumferential direction.
Is provided. The reference detection portion 92 extends spirally along the movement trajectory of the intake cam 27, as in the second embodiment.

In the present embodiment, the moving amount detection portion 93a extends in the axial direction of the intake camshaft 22 in a direction opposite to the reference detection portion 92 and in a spiral shape having the same twisting form. ing. In other words, the movement detection portion 93a and the reference detection portion 92 are twisted in the form of being symmetric with respect to the axis L of the intake camshaft 22, and in the same twisting manner and in opposite directions.

When the intake camshaft 22 rotates, the cam-side electromagnetic pickup 76 and each of the detected parts 92, 9
3a is passing by. At this time, each of the detected portions 9 passes by the cam-side electromagnetic pickup 76 as shown in FIG.
2 and 93a, there is only a portion facing the cam-side electromagnetic pickup 76 (a portion shown by oblique lines in the figure, hereinafter referred to as a facing portion 94).

The length of the facing portion 94 with respect to the axial direction of the intake camshaft 22 (the direction perpendicular to the arrow D in FIG. 14) is the same as the width of the cam-side electromagnetic pickup 76 indicated by the length between the dashed lines in the drawing. Value. The lengths Z of each of the facing portions 94 in the circumferential direction of the intake camshaft 22 (the direction of arrow D in the drawing) are equal to each other. This is because even though the torsion directions of the reference detected portion 92 and the moving amount detected portion 93a are opposite to each other, the torsion modes of the two are equal to each other.

When the cam-side electromagnetic pickup 76 and each of the opposing portions 94 pass each other, a pulse P2 corresponding to the opposing portion 94 of the reference detected portion 92 is generated from the pickup 76 as shown by a waveform X7 in FIG. , And a pulse P3 corresponding to the facing portion 94 of the pair of moving amount detected portions 93a. These pulses P2 and P3 have the same length Z in each of the facing portions 94, and therefore have the same pulse width.

Now, the cam-side electromagnetic pickup 76 has the waveform X
When the intake camshaft 22 is moved in the direction indicated by the arrow B in FIG. 12 by the operation of the valve timing adjustment mechanism 91 while the pulses P2 and P3 are generated in the mode shown by 7, the cam-side electromagnetic pickup 76 is shown by a waveform X8. Pulses P2 and P3 are generated in this manner. That is,
The movement of the intake camshaft 22 causes the detected portions 92 and 93a to move relative to the cam-side electromagnetic pickup 76 as shown in FIG.
4 (a) as shown in FIG. 14 (b),
The facing portion 94 of the detected portions 92 and 93a is also shown in FIG.
The waveform X moves as shown in FIGS.
7 to waveform X8. In such a change from the waveform X7 to the waveform X8, the generation timing of the pulse P2 is not changed, and only the generation timing of the pulse P3 is changed.

The ECU 81 determines the amount of change in the generation timing of the pulse P3, that is, from the reference pulse P2 to the pulse P3.
To the intake camshaft 2
2 and the amount of change in the rotational phase relative to the crankshaft 15 are detected. The amount of change in the position of movement of the intake camshaft 22 in the axial direction and the relative rotational phase in the circumferential direction detected in this way are represented by pulses P2 and P2, respectively.
3, the respective pulse widths are equal to each other, so that the pulse width becomes more accurate as compared with the second embodiment.

If the torsion state of the movement detection section 93a is different from that of the reference detection section 92, the length Z of the facing portion 94 in the movement detection section 93a is equal to the length Z of the reference detection section 92. The value differs from the length Z of the facing portion 94.
As described above, when the length Z in each facing portion 94 is different,
Pulse P generated from cam-side electromagnetic pickup 76
2 and P3 have different pulse widths. Then, the movement position in the axial direction of the intake camshaft 22 and the circumferential direction detected by the difference between the pulse width of the pulse P2 and the pulse width of the pulse P3 based on the time t3 from the pulse P2 to the pulse P3. Error tends to occur in the amount of change in the relative rotation phase.

However, in the present embodiment, although the to-be-detected portion 92 and the moving amount to-be-detected portion 93a have opposite twisting directions, their torsion modes are equal to each other. The lengths Z of the opposed portions 94 of the 92 and 93a are equal to each other. as a result,
The pulse P2 corresponding to the facing portion 94 of the reference detected portion 92
Is equal to the pulse width of the pulse P3 corresponding to the facing portion 94 of the movement-amount-detected portion 93a.
Therefore, the movement position of the intake camshaft 22 in the axial direction and the amount of change in the relative rotational phase in the circumferential direction detected based on the time t3 become more accurate values.

As described in detail above, according to the present embodiment, the following effects can be obtained in addition to the effects of the second embodiment. Since the twisted state of the reference detected portion 92 and the displacement detected portion 93a are made equal to each other, the lengths Z of the respective opposed portions 94 are respectively equal to each other, and the pulse widths of the pulses P2 and P3 are also equal to each other. As a result, due to the difference between the pulse width of the pulse P2 and the pulse width of the pulse P3, the detected change amount of the movement position of the intake camshaft 22 in the axial direction and the change amount of the relative rotational phase in the circumferential direction are detected. It is possible to preferably prevent an error from occurring. Therefore, the detected change amount of the movement position and the relative rotation phase of the intake camshaft 22 can be made more accurate than in the case of the second embodiment.

The above embodiments can be modified as follows, for example. In the first embodiment, the number of the pair of reference detected parts 74 may be changed. That is, the number of the reference detection portions 74 may be one, or three or more.

In the first embodiment, the pair of reference detected parts 74 may be omitted. In this case, the change amount of the generation timing of the pulse P3 is changed from the pulse P1 to the pulse P3.
It will be determined based on the time until. In this configuration, the number of the movement amount detected portions 75 may be two as shown in FIG. 15, or three or more.

In the first embodiment, the crank-side detected portion 72 and the crank-side electromagnetic pickup 73 may be omitted. Also in this case, the amount of change in the generation timing of the pulse P3 is determined by the time t1 from the pulse P2 to the pulse P3.
The movement position of the intake cam 27 in the axial direction of the intake camshaft 22 can be detected from the time t1.

In the first embodiment, the intake valve 20 is moved only by moving the intake camshaft 22 in the axial direction.
The cam profile of the intake cam 27 may be changed so that the opening / closing timing of the intake cam 27 is changed. In this case, a valve timing adjustment mechanism 24 for changing the relative rotation phase of the intake camshaft 22 with respect to the crankshaft 15
Can be omitted.

In the second embodiment, the number of the reference detection portions 92 is set to two or more, or the movement amount detection portion 93
May be two or more. In the second embodiment, the reference detected portion 92 may be omitted. In this case, in order to generate a reference pulse instead of the pulse P2, a crank-side detected part 72 and a crank-side electromagnetic pickup 73 as in the first embodiment are provided on the crankshaft 15 side.

In the second embodiment, the moving amount detection portion 93 does not necessarily have to extend linearly. For example, the moving amount detection portion 93 may be formed so as to extend in a spiral shape different from the movement locus of the intake cam 27.

In the third embodiment, the reference detected part 92 may be omitted. In this case, in order to generate a reference pulse instead of the pulse P2, a crank-side detected portion having the same shape as the reference detected portion 92 and a crank-side electromagnetic member as in the first embodiment are provided on the crankshaft 15 side. A pickup 73 will be provided. Even with such a configuration, the same effect as in the third embodiment can be obtained.

In the third embodiment, the number of the movement amount detected portions 93a may be one, or three or more. Further, the number of the reference detection portions 92 may be two or more.

In each of the above embodiments, the reference detected parts 74 and 92 need not extend along the movement locus of the intake cam 27 in the axial direction of the intake camshaft 22. That is, in the first embodiment, for example, as shown in FIG. 16, the reference detected part 74 may be formed so as to extend spirally in a manner different from the movement amount detected part 75. In these cases, when the intake camshaft 22 moves in the axial direction, a pulse P2 corresponding to the reference detected parts 74, 92 is generated, and then the movement amount detected parts 75, 9 are generated.
Times t1 and t3 until the pulse P3 corresponding to 3, 93a is generated change according to the position of the intake camshaft 22 moving in the axial direction. Therefore, even in this case, the movement position of the intake camshaft 22 can be detected based on the times t1 and t3. Also in this case,
The relationship between the times t1 and t2 may be learned in advance.

In the above embodiments, each of the detected parts 72,
Although 74, 75, 92, 93 and 93a are provided on the shaft (crankshaft 15, intake camshaft 22) and the electromagnetic pickups 73 and 76 are provided outside the shaft, the present invention is not limited to this. That is, the electromagnetic pickups 73 and 76 are provided on the shafts, and the detected parts 72, 74, 75, 92, 93 and 93a are provided outside the shafts. The positional relationship with the parts 72, 74, 75, 92, 93, 93a may be reversed.

In the above embodiments, each of the detected parts 72,
Although 74, 75, 92, 93 and 93a protrude from the shaft, the present invention is not limited to this. For example,
A groove may be formed in the outer peripheral surface of the shaft to form a detected portion, or a magnet may be embedded in the outer peripheral surface to form a detected portion.

In the above embodiments, the valve characteristics of the intake valve 20 are changed. However, the valve characteristics of the exhaust valve 21 may be changed instead. In this case, the cam profile of the exhaust cam 28 is made the same as the cam profile of the intake cam 27 in each of the above embodiments. Further, the exhaust camshaft 23 can be moved in the axial direction, and the exhaust camshaft 23 can be moved.
To change the rotation phase.

[0102]

According to the first aspect of the present invention, the timing of the pulse generation from the pulse generating means is changed by the movement of the cam by the moving means. The moving position of the cam can be accurately detected. Therefore, even when the cam position is feedback-controlled to set an optimal cam profile according to the engine operating state, more accurate cam position information can be taken into the feedback system.

According to the second aspect of the present invention, when the cam is moved by the moving means, the generation timing of the pulse generated from the pulse generation means changes in response to the first and second detected parts. Since the first and second detected parts extend in different modes, the amount of change in the generation timing of the pulse corresponding to the first detected part and the change in the generation timing of the pulse corresponding to the second detected part are different. It will be different from the quantity. Therefore, it is possible to monitor the change in the generation timing of the pulses from the change in time from the generation of the pulse corresponding to the first detected part to the generation of the pulse corresponding to the second detected part. Therefore, the movement position of the cam in the direction of the camshaft axis detected by monitoring the amount of change in the generation timing of these pulses becomes more accurate.

According to the third aspect of the present invention, when the cam is moved by the moving means, the pulse generated by the pulse generating means in response to one of the first and second detected parts is detected. Although the generation timing changes, the generation timing of the pulse generated from the pulse generation means in response to the other detected portion does not change. Therefore, it is possible to monitor the amount of change in the generation timing of the pulse generated in response to one of the detected parts, with reference to the pulse generated from the pulse generating means in response to the other detected part. Therefore, even without providing a detected part and a pulse generating means for generating a reference pulse on the output shaft side or the like of the internal combustion engine,
The movement position of the cam in the axial direction of the camshaft can be accurately detected. Then, even when the cam position is feedback-controlled to set an optimal cam profile according to the engine operating state, more accurate cam position information can be taken into the feedback system.

According to the fourth aspect of the present invention, since the detection widths of the first and second detected parts as viewed from the pulse generating means are always equal, the pulse width generated by the pulse generating means corresponds to the detected parts. The pulse width of the pulse to be output is always the same, and the occurrence timing can be detected more accurately.

According to the fifth aspect of the present invention, the timing of the pulse generated in response to the first detected portion is changed by the movement of the cam by the moving means. , It is possible to accurately detect the movement position of the cam in the axial direction of the camshaft. Therefore, even when the cam position is feedback-controlled to set an optimal cam profile according to the engine operating state, more accurate cam position information can be taken into the feedback system. The timing of the pulse generated in response to the second detected portion is not changed by the movement of the cam by the moving means, but is generated only by changing the rotation phase of the cam shaft by the phase changing means. Change. Therefore, by monitoring the change in the pulse generation timing, the change amount of the relative rotation phase of the camshaft with respect to the engine output shaft can be accurately detected. Then, even when the rotational phase of the camshaft is feedback-controlled to set the optimal camshaft rotational phase according to the engine operating state, more accurate camshaft rotational phase information can be taken into the feedback system. According to the invention described in claim 6, the first detected portion
Has a trajectory different from the trajectory of the cam
Because the cam is extended by the moving means,
When moving along a spiral trajectory in the direction, the first detected
Of pulse generated by pulse generation means in response to the
The raw timing changes. Therefore, the pulse generator
By monitoring the change in the imaging, the axis of the camshaft can be monitored.
The position of the cam in the direction can be accurately detected.
Become like Then, the cam position is feedback controlled.
Optimal cam profile according to engine operating conditions
More accurate cam position information.
It will be possible to take it into the dock system. Also, above
As described above, based on the accurately detected cam movement position,
Rotational phase change of camshaft relative to engine output shaft
Can be accurately detected. And mosquito
Feedback control of the rotational phase of the
Set the optimal camshaft rotation phase according to the rotation state
If so, more accurate camshaft rotation phase information
Can be incorporated into the feedback system.
You.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a valve characteristic control device according to a first embodiment.

FIG. 2 is an exemplary sectional view showing a moving mechanism according to the embodiment;

FIG. 3 is an exemplary sectional view showing a valve timing adjusting mechanism according to the embodiment;

FIG. 4 is a cross-sectional view and a side view showing a crank-side detected portion and a crank-side electromagnetic pickup of the first embodiment.

FIGS. 5A and 5B are a cross-sectional view and a side view showing a reference portion and a movement amount detection portion and a cam-side electromagnetic pickup of the first embodiment.

FIG. 6 is a waveform diagram of a pulse signal output from each of the electromagnetic pickups.

FIG. 7 is a waveform diagram of a pulse signal output from each of the electromagnetic pickups.

FIG. 8 is a sectional view showing a valve characteristic control device according to a second embodiment.

FIG. 9 is a sectional view showing a valve characteristic control device according to a second embodiment.

FIGS. 10A and 10B are a cross-sectional view and a side view showing a reference portion and a movement amount detection portion and a cam-side electromagnetic pickup of a second embodiment.

FIG. 11 is a waveform diagram of a pulse signal output from the cam-side electromagnetic pickup.

12A and 12B are a cross-sectional view and a side view showing a reference portion and a movement amount detection portion and a cam-side electromagnetic pickup according to a third embodiment.

FIG. 13 is a waveform diagram of a pulse signal output from the cam-side electromagnetic pickup.

FIG. 14 is a plan view schematically showing a state in which each detected part and the cam-side electromagnetic pickup pass each other.

FIGS. 15A and 15B are a cross-sectional view and a side view showing another configuration example of the moving amount detection target portion and the cam-side electromagnetic pickup of the first embodiment.

FIG. 16 is a cross-sectional view and a side view showing another configuration example of the reference detected part and the cam-side electromagnetic pickup of the first embodiment.

FIG. 17 is a schematic diagram showing a conventional valve characteristic control device.

FIG. 18 is a perspective view showing a cam profile of an intake cam in a conventional valve characteristic control device.

[Explanation of symbols]

11 engine, 20 intake valve, 21 exhaust valve, 22 intake camshaft, 22a moving mechanism, 23
Exhaust camshaft, 24 ... valve timing adjustment mechanism,
27: intake cam, 28: exhaust cam, 74: detected part for reference, 75: detected part for movement, 76: cam side electromagnetic pickup, 91: valve timing adjustment mechanism, 92: detected part for reference, 93 , 93a... Detected portions for movement amount.

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI F02P 7/067 301 F02P 7/067 301A ( 56) references Patent Rights 8-312443 (JP, a) Patent Rights 9-217614 (JP, A) JP-A-11-218013 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 13/02 F01L 1/34 F01L 13/00 F02D 45/00

Claims (6)

(57) [Claims] 1. A cam provided on a camshaft for driving an intake valve or an exhaust valve of an internal combustion engine to open and close, wherein a cam profile changes in an axial direction of the camshaft.
Moving means for moving the cam in the axial direction of the camshaft, and by monitoring the position of the cam, moving the cam in the axial direction of the camshaft by the moving means, thereby obtaining the intake valve or A valve characteristic control device for an internal combustion engine that changes the opening / closing characteristic of the exhaust valve, wherein a detected part having a trajectory different from a movement trajectory of the cam moved by the moving means and extending in an axial direction of the cam shaft; and a pulse generating means for generating a pulse in response to the passage of該被detector caused by the rotation of the camshaft, the detected part which is generated from said pulse generating means
Generate a reference pulse for the pulse corresponding to
From the generation of this reference pulse,
A valve position control unit for detecting a moving position of the cam in the axial direction of the camshaft based on a time until a pulse is generated . 2. A cam provided on a camshaft for opening and closing an intake valve or an exhaust valve of an internal combustion engine, wherein a cam profile changes in an axial direction of the camshaft;
Moving means for moving the cam in the axial direction of the camshaft, and by monitoring the position of the cam, moving the cam in the axial direction of the camshaft by the moving means, thereby obtaining the intake valve or A valve characteristic control device for an internal combustion engine for changing an opening / closing characteristic of the exhaust valve, wherein first and second detected portions extending in different directions in an axial direction of the camshaft, Pulse generating means for generating a pulse in response to the passage of the first and second detected parts, and a pulse corresponding to each of the detected parts from the pulse generating means.
A valve characteristic control device for an internal combustion engine, wherein a movement position of the cam in the direction of the camshaft axis is detected based on a time from the occurrence of a pulse to the occurrence of a pulse . 3. The valve characteristic control device for an internal combustion engine according to claim 2, wherein one of said first and second detected parts has a locus identical to a locus of movement of said cam moved by said moving means. A valve characteristic control device for an internal combustion engine, wherein the valve characteristic control device extends in the axial direction of the camshaft. 4. The valve characteristic control device for an internal combustion engine according to claim 2, wherein the first and second detected portions are provided in a manner to be symmetric with respect to an axis of the camshaft. Valve characteristic control device for an internal combustion engine. 5. A cam provided on a camshaft for opening and closing an intake valve or an exhaust valve of an internal combustion engine, wherein a cam profile changes in an axial direction of the camshaft.
Moving means for moving the cam in the axial direction of the camshaft; and phase changing means for changing a relative rotation phase of the camshaft with respect to an output shaft of the engine. The position of the cam and the relative rotation of the camshaft By monitoring the phase change amount, moving the cam in the axial direction of the camshaft by the moving means, and changing the relative rotation phase of the camshaft with respect to the engine output shaft by the phase changing means, A valve characteristic control device for an internal combustion engine for changing an opening / closing characteristic of an intake valve or an exhaust valve, wherein a first trajectory extending in an axial direction of the camshaft has a trajectory different from a trajectory of the cam moved by the moving means. And the axis of the camshaft having the same locus as the locus of movement of the cam moved by the moving means. A second detection unit extending in a linear direction; and a pulse generation unit configured to generate a pulse in response to passage of the first and second detection units along with rotation of the camshaft,
Corresponding to the second detected part from the pulse generating means.
The pulse corresponding to the first detected part from the generation of the pulse
The position of movement of the cam in the axial direction of the camshaft is detected based on the time until the occurrence of the pulse.
A pulse corresponding to the second part to be detected, generated from a stage
A reference pulse is generated for
Of the pulse corresponding to the second detected part from the occurrence of the pulse
A valve characteristic control device for an internal combustion engine, wherein an amount of change in a relative rotation phase of the camshaft with respect to the engine output shaft is detected based on a time until the occurrence . 6. An intake valve or an exhaust valve of an internal combustion engine is opened.
The camshaft is provided on the camshaft for closing drive.
A cam whose cam profile changes in the axial direction of the shaft,
A trajectory of the cam spiraled in the axial direction of the camshaft.
Moving means for drawing and moving the cam,
And the relative rotational phase of the camshaft with respect to the engine output shaft
While monitoring the amount of change, move the cam with the moving means.
Draw a spiral miracle in the axial direction of the
By opening the intake valve or the exhaust valve,
In the valve characteristic control device of the internal combustion engine that changes the closing characteristic
Te, a moving locus of the cam to be moved by said moving means
Extending in the axial direction of the camshaft with different trajectories
Before being moved by the moving means
The cam shuff has the same locus as the moving locus of the cam.
A second detected portion extending in the axial direction of the
Passing through the first and second detected portions with the rotation of the shaft
Pulse generating means for generating a pulse in response to
Corresponding to the second detected part from the pulse generating means.
The pulse corresponding to the first detected part from the generation of the pulse
The camshaft of the cam based on the time until
Movement position in the shaft axis direction, and the cam shaft
Detecting a relative rotational phase change amount with respect to the engine output shaft;
A valve characteristic control device for an internal combustion engine, comprising: