JP4419813B2 - Intake control device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake control device for an internal combustion engine that controls intake air amount by variable control of lift and operating angle of an intake valve, and particularly relates to a learning technique for the control system.

  In a gasoline engine, the intake air amount is generally controlled by controlling the opening of a throttle valve provided in the intake passage. As is well known, this type of system has a particularly small throttle valve opening. There is a problem that the pumping loss is large at low load. On the other hand, attempts have been made to control the intake air amount without depending on the throttle valve by changing the opening / closing timing of the intake valve and the lift amount. Similarly, it has been proposed to realize a so-called throttle-less configuration in which the intake system is not equipped with a throttle valve.

  Patent Document 1 discloses a first variable valve mechanism that can simultaneously and continuously expand and contract the intake valve lift and operating angle previously proposed by the present applicant, and the center angle of the lift continuously. There is disclosed a variable valve operating apparatus that is combined with a second variable valve operating mechanism that causes the valve to move slowly. According to this type of variable valve device, as described above, it is possible to variably control the amount of air flowing into the cylinder without depending on the opening degree control of the throttle valve, particularly in a region where the load is small. In other words, so-called throttleless operation or operation with a sufficiently large opening of the throttle valve can be realized, and the pumping loss can be greatly reduced.

In Patent Document 2, in a configuration in which the intake air amount of an internal combustion engine is controlled using a throttle valve, the throttle valve is fully closed by a stopper mechanism in order to improve the accuracy of the control system. In addition, a technique for learning the opening degree detected by the throttle position sensor at this time as a fully closed position is disclosed.
JP 2002-256905 A JP-A-11-36896

  In the configuration in which the intake air amount is controlled by variable control of the lift / working angle of the intake valve as in Patent Document 1, the minimum value of the lift / working angle that can be realized by the variable valve mechanism is set as the target value during idling. If the minimum position is restricted by the stopper mechanism, when the actual lift amount varies due to various factors, the intake amount during idling may be insufficient, and the engine operation may be stopped. Therefore, it is not appropriate to learn the control system by restricting the minimum position by the stopper mechanism as in Patent Document 2.

The present invention includes a variable valve mechanism that can continuously increase and decrease the lift and operating angle of the intake valve, and controls the intake amount of the internal combustion engine by controlling the lift and operating angle according to engine operating conditions. In the intake control apparatus for an internal combustion engine, the learning position for learning the control system of the variable valve mechanism is a position other than the minimum value and the maximum value of the lift / operating angle that can be realized by the variable valve mechanism. A predetermined lift / operating angle position is set , and the learning is performed by temporarily restricting the position of the variable valve mechanism at a predetermined lift / operating angle position by a stopper mechanism that can be released . As a result, it is possible to learn the control system not only when starting the internal combustion engine but also during operation.

  More specifically, the learning position is a lift / operation angle when the internal combustion engine is idling. As a result, there are many opportunities to learn the lift / operating angle, and stable idling can be performed by controlling the lift / operating angle with high accuracy.

  Preferably, the learning position is a lift / operation angle during idling after warm-up. In this way, the lift / operating angle can be learned without being affected by variations in the lift amount due to uneven temperature during warm-up, and idle operation with a more stable lift / operating angle becomes possible. .

According to a fourth aspect of the present invention, the variable valve mechanism includes a control shaft whose rotation angle position is controlled by an actuator for controlling a lift / operation angle, and a lift / operation angle corresponding to the rotation angle position of the control shaft. anda cam mechanism for transmitting to the intake valve rotary motion of the drive shaft as an opening and closing movement of the stopper mechanism, position the rotational angle position of the control shaft in the lift operation angle position at which the calibration position. As the stopper mechanism, a stopper pin that functions only during learning is used.

  In a more specific invention of claim 5, the stopper mechanism includes a first stopper position that defines the minimum value or maximum value, and a second stopper position that defines a lift / operation angle as the learning position. It is equipped with. Therefore, for example, at the time of predetermined learning, the rotation angle position of the control shaft is restricted to the second stopper position, and the learning of the lift / operation angle is performed in this state. At times other than learning, the rotation angle position of the control shaft is regulated at the first stopper position.

  According to a sixth aspect of the present invention, the stopper mechanism comprises a releasable stopper pin disposed on the cylinder head. In other words, it functions as a stopper during learning, and when it is not during learning, for example, the stopper function is canceled by retreating.

  According to a seventh aspect of the present invention, the stopper mechanism comprises a releasable stopper pin disposed on an arm attached to the end of the control shaft.

  According to the present invention, learning of the control system of the variable valve mechanism that can continuously increase / decrease the lift / operating angle of the intake valve can be performed not only when the internal combustion engine is started but also during operation. In addition, the control of the minute lift amount during idling is not impaired.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing the configuration of a variable valve operating device that opens and closes an intake valve 3 of an internal combustion engine according to the present invention. The variable valve operating device continuously increases the lift and operating angle of the intake valve 3. A first variable valve mechanism 1 that can be enlarged / reduced and a second variable valve mechanism 2 that can continuously delay the central angle of the operating angle are provided. The first and second variable valve mechanisms 1 and 2 are controlled by the control unit 4 in accordance with operating conditions.

  The first variable valve mechanism 1 and the second variable valve mechanism 2 described above are known from the above-described Patent Document 1 and the like, and therefore only the outline thereof will be described.

  A first variable valve mechanism 1 that variably controls a lift and an operating angle is rotatably supported by a drive shaft 5 driven by a crankshaft of an internal combustion engine, an eccentric cam 6 fixed to the drive shaft 5. The eccentric cam 6 includes a control shaft 7, a rocker arm 9 that is swingably supported by the eccentric cam portion 8 of the control shaft 7, and a swing cam 11 that contacts the tappet 10 of the intake valve 3. The rocker arm 9 is linked by a link arm 12, and the rocker arm 9 and the swing cam 11 are linked by a link member 13.

  The rocker arm 9 is supported at its substantially central portion so as to be swingable by the eccentric cam portion 8, and an arm portion of the link arm 12 is linked to one end thereof via a connecting pin 15, and the like. The upper end portion of the link member 13 is linked to the end portion via a connecting pin 16. The eccentric cam portion 8 is eccentric from the axis of the control shaft 7, and accordingly, the rocking center of the rocker arm 9 changes according to the angular position of the control shaft 7.

  The swing cam 11 is rotatably supported by being fitted to the outer periphery of the drive shaft 5, and the lower end portion of the link member 13 is linked to the end portion extending laterally via a connecting pin 17. ing. On the lower surface of the swing cam 11, a base circle surface concentric with the drive shaft 5 and a cam surface extending in a predetermined curve from the base circle surface are continuously formed. These base circle surface and cam surface abut on the upper surface of the tappet 10 according to the swing position of the swing cam 11.

  The control shaft 7 is configured to rotate within a predetermined angle range by a lift / operating angle control actuator 21 provided at one end. The lift / operating angle control actuator 21 is, for example, an electric type that moves the rod 21a forward and backward, and is linked to a pin 24 provided on the actuator arm 23 at the end of the control shaft 7 via a fork member 22. The control shaft 7 is rotationally driven within a predetermined angle range. The actual rotation angle of the control shaft 7 is detected by a control shaft sensor (not shown).

  According to the first variable valve mechanism 1, the lift and operating angle of the intake valve 3 are continuously expanded and reduced simultaneously in accordance with the rotational angle position of the control shaft 7. With the change in size, the opening timing and closing timing of the intake valve 3 change substantially symmetrically. The size of the lift / operation angle is uniquely determined by the rotation angle of the control shaft 7, as shown in FIG.

  On the other hand, the second variable valve mechanism 2 that variably controls the central angle is configured such that the sprocket 31 provided at the front end of the drive shaft 5 and the sprocket 31 and the drive shaft 5 are relatively moved within a predetermined angle range. And a phase control actuator 32 that is rotated automatically. The sprocket 31 is linked to the crankshaft via a timing chain or timing belt (not shown). The phase control actuator 32 is composed of, for example, a hydraulic rotary actuator, and is controlled by a control signal from the control unit 4 via a hydraulic control valve (not shown). Due to the action of the phase control actuator 32, the sprocket 31 and the drive shaft 5 rotate relatively, and the lift center angle in the valve lift is retarded. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can also be obtained continuously. The control state of the second variable valve mechanism 2 is detected by a drive shaft sensor (not shown) that responds to the rotational position of the drive shaft 5.

  Accordingly, by combining the control of the first and second variable valve mechanisms 1 and 2, the opening timing and closing timing of the intake valve 3 can be variably controlled together with the lift amount, and the intake amount flowing into the cylinder according to the load is controlled. Can be controlled.

  FIG. 3 shows the configuration of the front end portion of the cylinder head 40 in which the above-described variable valve device is incorporated. As shown in the figure, the control shaft 7 having the actuator arm 23 at the end portion is connected to the cylinder head 40. The upper part is rotatably supported. The cylinder head 40 is provided with a stopper pin 41 serving as a stopper mechanism. When the side surface of the actuator arm 23 comes into contact with the stopper pin 41, rotation to one side of the control shaft 7, more specifically, a lift / operation angle. The rotation in the reduction direction is limited. Here, as shown in FIG. 4, the stopper pin 41 has a small-diameter portion 41 a serving as a first stopper position and a large-diameter portion 41 b serving as a second stopper position, and the stopper pin 41 is a cylinder head 40. On the other hand, the small diameter portion 41 a or the large diameter portion 41 b can come into contact with the actuator arm 23 by protruding and protruding in the axial direction. That is, the substantial stopper position is switched. Various appropriate mechanisms can be used as the protruding and retracting mechanism of the stopper pin 41. For example, as shown in FIG. By introducing through the switching valve 43, the stopper pin 41 can be slid. The stopper pin 41 is always urged in the backward direction by the return spring 44, and moves in the protruding direction when the hydraulic pressure is introduced.

  The first stopper position by the small diameter portion 41a corresponds to the 0 point position of the rotation angle θcs of the control shaft 7 shown in FIG. At this time, the lift / operating angle becomes the minimum value. However, this position is outside the normal control range. The second stopper position by the large-diameter portion 41b corresponds to the lift / working angle at the time of idling (specifically, at the time of idling after the completion of warm-up) shown in FIG. 2, in other words, the learning position of the lift / working angle. Corresponding to In this way, by setting the lift / operating angle at the time of idling to be slightly larger than the minimum value of the lift / operating angle that can be realized by the first variable valve mechanism 1, it depends on various factors. Even if there is a variation in the actual lift amount, it is possible to secure the necessary intake air amount during idling, and it will not be impossible to operate.

  In the above configuration, the stopper pin 41 is in the retracted position except when learning is performed, and only the small-diameter portion 41a on the tip side protrudes. Therefore, even when the control shaft 7 rotates in the direction of reduction of the lift / operating angle, for example, even if the control shaft 7 overshoots due to a control response delay or the like, the control shaft 7 is reliably regulated to the predetermined 0 point position and rotated further. Never do.

  Further, when a predetermined learning condition is satisfied during idle operation after warming up, hydraulic pressure is supplied by the electromagnetic switching valve 43 to bring the stopper pin 41 into the protruding position, and the large diameter portion 41b to the position corresponding to the actuator arm 23. At the same time, the control shaft 7 is driven by the actuator 21 in the lift / reduction direction of the operating angle to bring the actuator arm 23 into contact with the large-diameter portion 41b. The actual lift / operation angle at this time, that is, the actual rotational angle position of the control shaft 7 is detected by a control shaft sensor (not shown) and learning is performed. This learning may be performed every time the driving condition becomes idle, or may be performed at an appropriate frequency such as only for the first time. When the learning is completed, the control of the control shaft 7 is returned to the normal control, and the stopper pin 41 is moved backward as described above.

  Note that the stopper pin 41 is not limited to the illustrated cylindrical shape, and various shapes are possible.

  Next, FIG. 6 shows a first stopper pin 45 that defines a first stopper position corresponding to the minimum value of the lift / operating angle as a stopper mechanism, and a second stopper corresponding to the lift / operating angle during idling. The second stopper pin 46 for defining the position and the cylinder head 40 are shown in the embodiment. Here, the first stopper pin 45 is a pin fixed to the cylinder head 40, and always mechanically prevents excessive rotation of the control shaft 7 (rotation smaller than the zero point position). On the other hand, the second stopper pin 46 is a retractable pin having the same retracting mechanism as in FIG. 5 described above, and is a protruding position only during learning, and restricts the control shaft 7 to the learning position.

  Next, FIG. 7 shows an embodiment in which a retractable stopper pin 48 is provided on the side of the actuator arm 23 fixed to the end of the control shaft 7. The stopper pin 48 is slidably fitted to the cylinder 49 of the actuator arm 23 and protrudes by supplying hydraulic pressure through an oil passage 50 passing through the actuator arm 23. In this projecting position, the tip of the stopper pin 48 comes into contact with a stopper member (not shown) on the other side, so that the learning position corresponding to the idle is regulated. At times other than learning, the stopper pin 48 is in the retracted position, and the actuator arm 23 itself comes into contact with the counterpart stopper member, so that the lift / operating angle is restricted to the minimum value. The supply / release of the hydraulic pressure can be performed by the electromagnetic switching valve similar to that shown in FIG.

Structure explanatory drawing which shows a variable valve apparatus. The characteristic view which shows the relationship between the rotation angle of a control shaft, and a lift and an operating angle. The front view of a cylinder head end part. The (A) front view and (B) side view of a stopper pin. Explanatory drawing which shows the raising / lowering mechanism of a stopper pin. The front view of the cylinder head end which shows the Example using two stopper pins. The rear view of the actuator arm which provided the stopper pin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st variable valve mechanism 3 ... Intake valve 7 ... Control shaft 41 ... Stopper pin 41a ... Small diameter part 41b ... Large diameter part

Claims (7)

Equipped with a variable valve mechanism that can continuously increase / decrease the lift / working angle of the intake valve, and control the lift / working angle according to the engine operating conditions to control the intake air amount of the internal combustion engine. an intake control device for an internal combustion engine, a learning position for learning the control system of the variable valve mechanism, a predetermined between in other than the minimum value and the maximum value of the lift operating angle achievable by the variable valve mechanism An intake air control for an internal combustion engine characterized by a lift / operating angle position, and the position is temporarily regulated by a stopper mechanism capable of releasing the variable valve mechanism at the predetermined lift / operating angle position to perform the above learning. apparatus.   2. The intake control apparatus for an internal combustion engine according to claim 1, wherein the learning position is a lift / operating angle during idling of the internal combustion engine.   The intake control apparatus for an internal combustion engine according to claim 2, wherein the learning position is a lift / operating angle during idling after warm-up. The variable valve mechanism includes a control shaft whose rotation angle position is controlled by an actuator for controlling a lift / operation angle, and a drive shaft as an opening / closing movement of the lift / operation angle according to the rotation angle position of the control shaft. A cam mechanism for transmitting rotational motion to the intake valve,
The stopper mechanism comprises an intake control device for an internal combustion engine according to claim 1, wherein the benzalkonium be positioned a rotational angle position of the control shaft in the lift operation angle position at which the calibration position . The stopper mechanism includes a first stopper position that defines the minimum value or the maximum value, and a second stopper position that defines a lift / operation angle as the learning position. Item 5. An intake control device for an internal combustion engine according to any one of Items 1 to 4 . The stopper mechanism comprises an intake control device for an internal combustion engine according to claim 1, characterized in that it consists of releasable stopper pin disposed in the cylinder head. 5. The intake control device for an internal combustion engine according to claim 4, wherein the stopper mechanism includes a releasable stopper pin disposed on an arm attached to an end of the control shaft.

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