JP2008291790A - Control device for valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit renewal of a controlled value by mistake according to operation conditions of an actuator in a control device for a valve system provided with an elastic body generating reaction force in response to operation of the actuator. <P>SOLUTION: The valve system for the internal combustion engine includes the actuator 60 changing maximum lift of an engine valve by operating in an operation range. The actuator 60 is provided with a washer 67 generating reaction force when the same is operated to a mechanism limit position of an operation range thereof in a deformation zone. The control device for the valve system is provided with a learning means executing a control value learning renewing the controlled value of the actuator 60 to the controlled value corresponding to the mechanical limit position by operating the actuator 60 to a mechanical limit position when predetermined learning conditions are satisfied, and a learning restart means restarting controlled value learning after operating to a reverse side of the mechanical limit position when the actuator 60 temporarily stops in the deformation zone during execution of controlled value learning by the learning means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is applied to a valve operating system including an elastic body that generates a reaction force against the operation of an actuator, detects a change amount from a predetermined initial value of a control value of the actuator, and determines the initial value and the change amount. The present invention relates to a valve system control device that calculates a control value of an actuator based on the control value.

  In recent years, in order to improve the fuel efficiency and output of internal combustion engines, a target value for the maximum lift amount of the engine valve is set based on the engine operating state, and the maximum lift amount is feedback-controlled to match the target value. An intake system control device is employed (see, for example, Patent Document 1). In such an intake system control device, the following configuration is generally employed. That is, in this control device, an actuator that operates within a mechanically regulated operating range to change the valve characteristics of the engine valve, and a change amount from a predetermined initial value for the control value of the actuator are detected. Sensor. Such a control device calculates the control value of the actuator based on the initial value and the change amount, in other words, the maximum lift amount of the engine valve, and calculates the control value and the target value set based on the engine operating state. The actuator is operated so that the deviation is small.

Further, in this control device, when a predetermined learning condition is satisfied, the actuator is operated to the mechanical limit position of the operation range, and the mechanical limit is determined when it is determined that the operation of the actuator is stopped. The control value corresponding to the position is learned, and the control value of the actuator calculated at that time is updated to the learned control value. By performing such control value learning, for example, even when a deviation occurs between the control value of the actuator calculated due to, for example, a change in sensor characteristics and the control value corresponding to the actual position, The calculated control value of the actuator can be matched with the control value corresponding to the actual position.
JP 2005-201117 A

  Incidentally, contact failure or the like may occur in the power supply circuit or communication circuit of the valve-operated control device, and a temporary stop of control by the control device, that is, a so-called instantaneous interruption may occur. For example, if such an instantaneous interruption occurs before the actuator reaches the mechanical limit position during execution of the control value learning described above, the operation of the actuator controlled by the control device is temporarily stopped.

  Here, in order to suppress unnecessary displacement of each drive member of the actuator, a structure in which an elastic body such as a washer is provided between the drive members may be employed. And when this elastic body produces the reaction force with respect to the action | operation of an actuator, there exists a possibility of affecting the action | operation of an actuator. In addition, as described above, when the operation of the actuator by the control device is temporarily stopped, the degree of deformation of the elastic body may be changed depending on the operation state of the actuator. As a result, when the actuator does not reach the mechanical limit position, the control value of the actuator is erroneously updated to a value different from the control value corresponding to the actual position.

  The present invention has been made in view of such circumstances, and an object of the present invention is to update a control value by mistake depending on an operating state of an actuator in a valve system control device including an elastic body that generates a reaction force against the operation of the actuator. It is to suppress doing.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 includes an actuator that changes a valve characteristic of the engine valve by operating within a mechanically regulated operating range, and the actuator is placed in the deformation range of the actuator within the operating range. A change applied to a valve train provided with an elastic body that generates a reaction force against the operation of the actuator when operating to the mechanical limit position, and detecting a change amount from a predetermined initial value for the control value of the actuator A quantity detection means; a calculation means for calculating a control value of the actuator based on the initial value and the change amount; and when the predetermined learning condition is satisfied, the actuator is operated to a mechanical limit position of the operating range. The control value calculated by the calculation means when the operation of the actuator is stopped is the mechanical limit position. And a learning means for executing control value learning for updating to a corresponding control value. The actuator is temporarily stopped in the deformation region during execution of control value learning by the learning means. Sometimes, the gist is provided with learning resumption means for resuming control value learning by the learning means after operating the actuator to the opposite side of the mechanical limit position.

  According to this configuration, when the actuator temporarily stops in the deformation region of the elastic body during execution of the control value learning, the actuator is operated to the opposite side of the mechanical limit position, thereby The reaction force against the operation can be once reduced. Then, the control value learning by the learning means is resumed in a state where the reaction force of the elastic body is relatively small, and when the actuator is operated to the mechanical limit position, the actuator operates to the previous stop position with a predetermined operating inertia force. can do. Thus, for example, when the control value learning is resumed directly from the stop position of the actuator, in other words, compared to the case where the actuator is operated to the mechanical limit position under the state where the operation inertia force is “0”. The actuator can be easily operated to the mechanical limit position. Therefore, even when the actuator is temporarily stopped in the deformation region during execution of the control value learning by the learning means, the actuator does not reach the mechanical limit position due to a decrease in the operating inertia force of the actuator. This can be suppressed. As a result, it is possible to suppress erroneous updating of the control value depending on the operating state of the actuator.

  In addition, as described in claim 2, the learning resuming unit employs a configuration in which the learning of the control value is resumed after the actuator is operated outside the deformation region of the elastic body. Is desirable. As a result, the control learning is resumed after the actuator is actuated to a position where the reaction force against the actuation of the actuator by the elastic body is “0”, so that the actuator is mechanically limited due to a decrease in the actuator inertial force. It is possible to effectively prevent the position from being reached.

  Hereinafter, an embodiment in which the present invention is applied to a control device for a valve train of an internal combustion engine mounted on a vehicle will be described with reference to FIGS. Here, FIG. 1 is a sectional view showing a partial sectional structure of a valve operating system of an internal combustion engine mounted on a vehicle, and FIG. 2 is a plan view showing an arrangement mode of the valve operating system of the internal combustion engine. .

  As shown in FIGS. 1 and 2, the internal combustion engine has four cylinders (only one is shown in FIG. 1), and a cylinder head 2 includes a pair of exhaust valves 10 corresponding to these cylinders. An intake valve 20 is provided so as to be able to reciprocate. The cylinder head 2 is provided with an exhaust valve opening / closing device 90 and an intake valve opening / closing device 100 corresponding to the exhaust valve 10 and the intake valve 20, respectively.

  The exhaust valve opening / closing device 90 is provided with a lash adjuster 12 corresponding to each exhaust valve 10, and a rocker arm 13 is installed between the lash adjuster 12 and the exhaust valve 10. The base end of the rocker arm 13 is supported by the lash adjuster 12, and the tip end is in contact with the base end portion of the exhaust valve 10. Further, an exhaust camshaft 14 is rotatably supported by the cylinder head 2, and the exhaust camshaft 14 is rotated in conjunction with the rotation of the engine output shaft. A plurality of cams 15 are formed on the exhaust camshaft 14, and a roller 13 a provided at an intermediate portion of the rocker arm 13 is in contact with the outer peripheral surface of the cams 15. The exhaust valve 10 is provided with a retainer 16, and a valve spring 11 is provided between the retainer 16 and the cylinder head 2. The exhaust valve 10 is urged in the valve closing direction by the urging force of the valve spring 11. Thereby, the roller 13 a of the rocker arm 13 is pressed against the outer peripheral surface of the cam 15. When the cam 15 rotates during engine operation, the rocker arm 13 swings with the portion supported by the lash adjuster 12 as a fulcrum. As a result, the exhaust valve 10 is driven to open and close by the rocker arm 13. Note that the valve spring 11 is compressed as the opening of the exhaust valve 10, that is, the lift amount increases, and the reaction force of the valve spring 11 against the operation of the exhaust valve opening / closing device 90 increases.

  On the other hand, the intake valve opening / closing device 100 is provided with a valve spring 21, a retainer 26 provided on the intake valve 20, a rocker arm 23, and a lash adjuster 22 as in the exhaust side. An intake camshaft 24 in which a plurality of cams 25 are formed is rotatably supported on the cylinder head 2, and the intake camshaft 24 is also rotated in conjunction with the rotation of the engine output shaft. Here, unlike the exhaust valve opening / closing device 90, the intake valve opening / closing device 100 is provided with an intermediate drive mechanism 50 between the cam 25 and the rocker arm 23. The intermediate drive mechanism 50 has an input unit 51 and a pair of output units 52, and the input unit 51 and the output unit 52 are swingably supported by a support pipe 53 fixed to the cylinder head 2. . The rocker arm 23 is urged toward the output portion 52 by the urging force of the lash adjuster 22 and the valve spring 21, and a roller 23 a provided at an intermediate portion of the rocker arm 23 is brought into contact with the outer peripheral surface of the output portion 52. Yes. As a result, the input portion 51 is urged to swing in the counterclockwise direction W1 together with the output portion 52, and the roller 51a provided at the tip of the radially extending portion of the input portion 51 presses the outer peripheral surface of the cam 25. Is done.

  In such an intake valve opening / closing device 100, when the cam 25 rotates during engine operation, the cam 25 presses the input portion 51 while being in sliding contact with the roller 51a, whereby the output portion 52 swings in the circumferential direction of the support pipe 53. It becomes like this. When the output unit 52 swings, the rocker arm 23 swings with the portion supported by the lash adjuster 22 as a fulcrum. As a result, the intake valve 20 is driven to open and close by the rocker arm 23. Note that the valve spring 21 is compressed as the opening of the intake valve 20, that is, the lift amount increases, and the reaction force of the valve spring 21 against the operation of the intake valve opening / closing device 100 increases.

  A control shaft 54 that can be driven along the axial direction of the support pipe 53 is inserted. The control shaft 54 is drivingly connected to the input unit 51 and the output unit 52 via a connecting member. When the control shaft 54 is driven along the axial direction, the input unit 51 and the output unit 52 are relatively swung. Next, the intermediate drive mechanism 50 that connects the control shaft 54, the input unit 51, and the output unit 52 will be described in detail with reference to FIG. FIG. 3 is a partially broken perspective view showing the internal structure of the mediation drive mechanism 50.

  As shown in FIG. 3, the input unit 51 is provided between a pair of output units 52, and a substantially cylindrical communication space is formed inside the input unit 51 and the output unit 52. Further, a helical spline 51h is formed on the inner peripheral surface of the input unit 51, and a helical spline 52h in which the helical spline 51h of the input unit 51 and its teeth are inclined in the opposite direction are formed on the inner peripheral surface of the output unit 52. Is formed.

  A substantially cylindrical slider gear 55 is provided in a space formed inside the input unit 51 and the output unit 52. A helical spline 55a that meshes with the helical spline 51h of the input portion 51 is formed at the central portion of the outer peripheral surface of the slider gear 55, and both ends of the outer peripheral surface mesh with the helical spline 52h of the output portion 52. A helical spline 55b is formed.

  Further, a groove 55c extending along the circumferential direction is formed on the inner wall of the substantially cylindrical slider gear 55, and a bush 56 is fitted in the groove 55c. The bush 56 can slide on the inner peripheral surface of the groove 55c along the direction in which the groove 55c extends, but the relative displacement in the axial direction with respect to the slider gear 55 is restricted by the groove 55c.

  The support pipe 53 is inserted into a through space formed inside the slider gear 55, and the control shaft 54 is inserted into the support pipe 53. A long hole 53 a extending in the axial direction is formed in the tube wall of the support pipe 53. A locking pin 57 is provided between the slider gear 55 and the control shaft 54 to connect the slider gear 55 and the control shaft 54 through a long hole 53a. One end of the locking pin 57 is inserted into a recess (not shown) formed in the control shaft 54, and the other end is inserted into a through hole 56 a formed in the bush 56.

  In such an intermediate drive mechanism 50, when the control shaft 54 is displaced along the axial direction, the slider gear 55 is displaced in the axial direction in conjunction with the displacement. The helical splines 55a and 55b formed on the outer peripheral surface of the slider gear 55 are meshed with the helical splines 51h and 52h formed on the inner peripheral surfaces of the input portion 51 and the output portion 52, respectively. When displaced in the axial direction, the input unit 51 and the output unit 52 rotate in opposite directions. As a result, the relative phase difference between the input unit 51 and the output unit 52 is changed, and the maximum lift amount of the intake valve 20 is changed.

  Here, as shown in FIG. 2, an electric actuator 60 (hereinafter simply referred to as “actuator 60”) is provided at the base end portion (right end portion in the figure) of the control shaft 54. The actuator 60 is driven by a microcomputer 70. Hereinafter, the structure of the actuator 60 will be described in detail with reference to FIG. FIG. 4 is a partial sectional view mainly showing the structure of the actuator 60.

  As shown in FIG. 4, the housing 60 a of the actuator 60 is attached to the cylinder head 2. Inside the housing 60a, there is a motor 61 having a stator 61a having a coil C and a rotor 61b having a permanent magnet, and a planetary gear mechanism 62 that converts the rotation of the motor 61 into a linear motion and transmits it to the control shaft 54. And are provided.

  This planetary gear mechanism 62 has an output shaft 63 provided with a spiral spline on the outer periphery, a plurality of planetary gears 64 provided on the outer periphery and a roller nut 65 provided on the inner periphery. Configured.

  The output shaft 63 is supported by the housing 60a so as to be able to be displaced in the axial direction and not to rotate about the axis L, and its tip end portion (left end portion in FIG. 4) is connected to the control shaft 54 by a connecting member 68. Yes. The roller nut 65 is supported by a housing 60a via a double row angular bearing 66 so as to be rotatable integrally with the rotor 61b.

  The bearing 66 includes an outer ring 66a fixed to the housing 60a, two inner rings 66b and 66c provided on the outer periphery of the roller nut 65, and two ball rows 66d and 66e corresponding to the inner rings 66b and 66c, respectively. ing. The inner rings 66 b and 66 c are arranged in parallel between stoppers 65 a and 65 b fitted on the outer periphery of the roller nut 65. A washer 67 is provided in a compressed state between the stopper 65a and the inner ring 66b. Unnecessary displacement of the inner rings 66b and 66c is suppressed by the elasticity of the washer 67. The ball row 66d, the outer ring 66a, and the inner ring 66b have a contact angle θ, while the ball row 66e, the outer ring 66a, and the inner ring 66c have a contact angle −θ. With such a bearing 66, it is possible to receive a radial load (a load in a direction perpendicular to the axis L) and an axial load (a load in a direction parallel to the axis L).

  Further, the planetary gears 64 are arranged at equal angles between the output shaft 63 and the roller nut 65. The spline of the planetary gear 64 meshes with both the spline of the output shaft 63 and the spline of the roller nut 65 fitted on the output shaft 63, and the planetary gear 64 is connected between the output shaft 63 and the roller nut 65. It is formed to rotate while revolving around 63.

  When the coil 60 of the stator 61a is energized by such an actuator 60, the rotor 61b and the roller nut 65 are rotated about the axis L, and each planetary gear 64 rotates around its own axis while rotating around the axis L. Revolve. Further, as described above, the output shaft 63 cannot rotate about the axis L, but can be displaced in the axial direction, so that the output shaft 63 is displaced in the axial direction by the rotation and revolution of each planetary gear 64. To do.

  As the output shaft 63 is displaced in the axial direction, the control shaft 54 is displaced in the axial direction, so that the drive state of the intermediate drive mechanism 50 is changed, and the maximum lift amount of the intake valve 20 is continuously changed. Become. Specifically, when the control shaft 54 moves in the direction F in FIG. 4, the maximum lift amount decreases, while when the control shaft 54 moves in the direction R in FIG. 4, the maximum lift amount increases.

  Two stoppers 63a and 63b that can come into contact with the housing 60a are fixed to the output shaft 63, and the output shaft 63, in other words, the control shaft 54 is driven in a drive section regulated by these stoppers 63a and 63b. It is possible. When the output shaft 63 is displaced to a limit position where the stopper 63a contacts the housing 60a (hereinafter referred to as “Hi end”), the maximum lift amount becomes the design maximum value, while the stopper 63b contacts the housing 60a. When the output shaft 63 is displaced to a position (hereinafter referred to as “Lo end”), the maximum lift amount becomes the design maximum value.

  Here, when a driving force for driving the output shaft 63 in the R direction by the actuator 60 is generated with the stopper 63a in contact with the housing 60a, the movement of the output shaft 63 in the direction R is restricted. A reaction force that drives the roller nut 65 in the direction F is generated. This reaction force is transmitted to the inner ring 66c of the bearing 66 through the stopper 65b. As described above, since the axial load can be received by the bearing 66, specifically, the load transmitted to the inner ring 66c is received by the protrusion 60b of the housing 60a via the ball row 66e and the outer ring 66a. Movement of the nut 65 in the direction F is restricted. That is, when the stopper 63a is displaced to the Hi end, the actuator 60 reaches the mechanical upper limit position of the operation range, and the operation amount of the actuator 60 becomes the design maximum value corresponding to the upper limit position.

  On the other hand, when the driving force for driving the output shaft 63 in the F direction by the actuator 60 is generated with the stopper 63b in contact with the housing 60a, the movement of the output shaft 63 in the direction F is restricted. A reaction force that drives the roller nut 65 in the direction R is generated. This reaction force is transmitted to the washer 67 through the stopper 65a. Since the axial load can be received by the bearing 66, specifically, the load transmitted to the washer 67 is received by the projection 60c through the inner ring 66b, the ball row 66d, and the outer ring 66a. The roller nut 65 is displaced in the direction R by the amount compressed by the washer 67 while rotating. When the washer 67 is compressed to the compression limit state, the displacement of the roller nut 65 stops, the actuator 60 reaches the mechanical lower limit position of the operation range, and the operation amount of the actuator 60 reaches the lower limit position. Corresponding design minimum value.

  Since the stoppers 63a and 63b and the housing 60a frequently come into contact with each other, there is a risk of damaging the members. Therefore, during normal control, the output shaft 63 is more than the drive space regulated by the stoppers 63a and 63b. The displacement is made within a small section.

  The actuator 60 is provided with three electric angle sensors D1 to D3 and an eight-pole multipolar magnet (not shown) that rotates integrally with the roller nut 65 corresponding to the electric angle sensors D1 to D3. These electric angle sensors D1 to D3 are pulse signals as shown in FIGS. 5A to 5C, that is, a logic high level signal “H” and a logic low signal in accordance with the magnetism of an 8-pole multipole magnet. The level signal “L” is alternately output. Note that the three electrical angle sensors D1 to D3 are arranged every 120 ° in the circumferential direction of the output shaft 63 so as to obtain such a pulse signal waveform. Therefore, the edge of the pulse signal output from one of these electrical angle sensors D1 to D3 is generated every 45 ° rotation of the output shaft 63. Further, the pulse signal from one of these electrical angle sensors D1 to D3 is shifted in phase to the advance side and the delay side by 30 ° rotation of the output shaft 63 with respect to the pulse signals from the other electrical angle sensors. It is in the state.

  The actuator 60 includes two position sensors S1 and S2 that function as rotary encoders, and a 48-pole multipolar magnet (not shown) that rotates integrally with the output shaft 63 corresponding to the position sensors S1 and S2. Is provided. These position sensors S1 and S2 are pulse signals as shown in FIGS. 5D and 5E, that is, a logic high level signal “H” and a logic low level according to the magnetism of the 48-pole multipole magnet. The signal “L” is alternately output. Note that the position sensor S1 is disposed at a distance of 176.25 ° from the position sensor S2 in the circumferential direction of the output shaft 63 so that such a pulse signal waveform can be obtained. Therefore, the edge of the pulse signal output from one of the position sensors S1, S2 is generated every 7.5 ° rotation of the output shaft 63. Further, the pulse signal from the position sensor S2 is in a state in which the phase is shifted from the pulse signal from the position sensor S1 to the advance side and the delay side by the 3.75 ° rotation of the output shaft 63.

  Here, the edge interval of the pulse signal combined with the electric angle sensors D1 to D3 is 15 °, whereas the edge interval of the pulse signal combined with the position sensors S1 and S2 is 3.75 °. Therefore, the edge of the pulse signal combined with the position sensors S1 and S2 is generated four times from the generation of the edge of the pulse signal combined with the electric angle sensors D1 to D3 to the next generation of the edge.

  The pulse signals output by the electrical angle sensors D1 to D3 and the position sensors S1 and S2 are taken into the microcomputer 70. The microcomputer 70 includes a central processing unit (CPU) 71 that performs numerical calculation and information processing by a program, a non-volatile memory (ROM) 72a that stores programs and data necessary for various controls, input data and calculation results. A volatile memory (DRAM) 72b for temporarily storing data, and a rewritable nonvolatile memory (EEPROM) 72c for storing a reference position obtained by learning control.

  The microcomputer 70 is connected to sensors for detecting the operating state of the engine, such as an accelerator sensor 74 for detecting the opening degree of the accelerator pedal of the vehicle and a crank angle sensor 75 for detecting the rotational phase of the crankshaft of the internal combustion engine. Has been. The microcomputer 70 sets a control target value for the maximum lift amount of the intake valve 20 based on the operating state of the engine, and based on the pulse signals output by the electrical angle sensors D1 to D3 and the position sensors S1 and S2 described above. The actual value of the maximum lift amount of the intake valve 20 is detected. Hereinafter, the procedure for detecting the actual value of the maximum lift amount of the intake valve 20 will be described in detail with reference to FIGS.

  Here, FIGS. 5A to 5E show the waveforms of the pulse signals output from the electrical angle sensors D1 to D3 and the position sensors S1 and S2 when the output shaft 63 of the actuator 60 rotates as described above. Yes. 5 (f) to 5 (h) show patterns in which the electrical angle count value E, the position count value P, and the stroke count value S change with respect to the change in the rotation angle when the actuator 60 rotates. . 6A shows the correspondence between the output signal patterns of the electrical angle sensors D1 to D3 and the electrical angle count value E, and FIG. 6B shows the output signals of the position sensors S1 and S2. A mode in which the position count value P increases or decreases when an edge occurs is shown.

First, each count value will be described.
[Electric angle count value E]
The electrical angle count value E is set based on the pulse signals of the electrical angle sensors D1 to D3 and represents the rotational phase of the motor 61. Specifically, as shown in FIG. 6A, depending on which of the logic high level signal “H” or the logic low level signal “L” is output from each of the electrical angle sensors D1 to D3. Thus, the electrical angle count value E is set to any one of continuous integer values in the range of “0” to “5” and stored in the DRAM 72b. The microcomputer 70 detects the rotational phase of the actuator 60 based on the electrical angle count value E stored in the DRAM 72b, and switches the energized phase of the coil C to rotate the motor forward and backward. Here, when the motor 61 rotates forward, the electrical angle count value E changes in the forward direction in the order of “0” → “1” → “2” → “3” → “4” → “5” → “0”. To do. On the other hand, when the actuator 60 rotates in the reverse direction, the electrical angle count value E changes from “5” → “4” → “3” → “2” → “1” → “0” → “5” in the reverse direction.

[Position count value P]
The position count value P represents the amount of change of the operating angle of the motor 61, in other words, the control value of the actuator 60 from the initial value when the engine is started. Specifically, of the position sensors S1 and S2, which one of the rising edges and the falling edges of the pulse signal is generated from one sensor, and the logic high level signal “H” and the logic low level signal from the other sensor. Depending on which “L” is output, either “+1” or “−1” is added to the position count value P (see FIG. 6B). In FIG. 6B, “↑” represents the rising edge of the pulse signal, and “↓” represents the falling edge of the pulse signal. The position count value P obtained by executing such processing is a value obtained by counting the edges of the pulse signals from the position sensors S1 and S2.

  Here, if the motor 61 is rotating forward, the position count value P is incremented by “1” for each edge of the pulse signal from the position sensors S1 and S2 shown in FIGS. 5 (d) and 5 (e). , The direction shown by the arrow A changes along the pattern shown in FIG. On the other hand, if the actuator 60 is rotating in the reverse direction, the position count value P is subtracted by “1” for each edge of the pulse signal, and in the direction indicated by the arrow B along the pattern shown in FIG. It will change. The position count value P is reset to “0” when the operation of the internal combustion engine is stopped. Therefore, the position count value P indicates how much the control value of the actuator 60 has changed with respect to the initial value when the engine is started, in other words, how much the maximum lift amount of the intake valve 20 is relative to the initial value when the engine is started. Indicates whether it has changed. The position count value P is stored in the DRAM 72b because it needs to be quickly added and subtracted based on the drive of the intake valve opening / closing device 100.

[Stroke count value S]
The stroke count value S represents the amount of change in the control amount of the actuator 60 with the control amount when the actuator 60 is operated to the mechanical lower limit position as the reference control amount, in other words, the actual value of the maximum lift amount. That is, as an initial setting of the stroke count value S, when the actuator 60 is operated to the mechanical lower limit position, the microcomputer 70 sets the stroke count value S to “0”. The microcomputer 70 adds the position count value P to the stroke count value S, and the stroke count value S is updated to the added value. The final value of the stroke count value S when the engine stop is completed and the drive of the intake valve opening / closing device 100 is stopped is learned as an initial value Sg at the start of the next engine operation and stored in the EEPROM 72c.

  Accordingly, the microcomputer 70 calculates the stroke count value S, in other words, the actual value of the maximum lift amount, based on the initial value Sg stored in the EEPROM 72c and the position count value P stored in the DRAM 72b. The microcomputer 70 controls the actuator 60 to perform feedback control so that the deviation between the actual value and the control target value set based on the engine operating state is small. As a result, the maximum lift amount of the intake valve 20 can be changed to a value suitable for the engine operating state, and the fuel efficiency and output of the internal combustion engine can be improved.

  By the way, when a deviation between the detected value of the position count value P and its actual value occurs due to changes in the sensor characteristics of the position sensors S1, S2, etc., a deviation between the calculated value of the stroke count value S and its actual value occurs. There is a possibility that the above-described feedback control of the maximum lift amount cannot be executed accurately.

  In this case, however, adverse effects due to such deviation can be suppressed by executing the following control value learning process. That is, for example, when a predetermined learning condition is satisfied, for example, when a change in sensor characteristics of the position sensors S1 and S2 is detected, the actuator 60 is first operated to its mechanical lower limit position. Specifically, as shown in FIG. 4, the actuator 60 is operated so that the stopper 63b of the output shaft 63 contacts the housing 60a, and then the operating inertia force of the actuator 60 and the driving of the actuator 60 described above. Due to the reaction force of the force, the roller nut 65 is displaced in the direction R and the washer 67 is compressed, and the control value of the actuator 60 enters the deformation region of the washer 67. Then, the washer 67 is compressed to its compression limit state by the operating inertia force and reaction force, and the control value of the actuator 60 calculated when the operation of the actuator 60 stops, that is, the stroke count value S corresponds to the mechanical limit position. Update to design minimum. Thereby, even when the sensor characteristics of the position sensors S1 and S2 change, the control value of the actuator 60 calculated based on the outputs of the position sensors S1 and S2 and the actual control value are matched. Can do.

  However, contact failure or the like may occur in the power supply circuit of the microcomputer 70, and a temporary stop of the control of the maximum lift amount by the microcomputer 70, so-called instantaneous interruption may occur. When such an instantaneous interruption occurs, the operation of the actuator 60 controlled by the microcomputer 70 is temporarily stopped. Here, for example, when the control by the microcomputer 70 is momentarily interrupted after the control value of the actuator 60 enters the deformation region of the washer 67 during execution of the control value learning described above, the compression amount of the washer 67 is relatively large. Thus, the operation of the actuator 60 may stop. Then, after the control of the microcomputer 70 returns from the temporarily stopped state, the operating inertia force that displaces the roller nut 65 in the direction F becomes “0”. In this case, the reaction force against the driving force of the actuator 60 may cause the actuator 60 to stop before reaching its mechanical lower limit position. As described above, when the actuator 60 does not reach the mechanical lower limit position, it is determined that the actuator 60 has been operated up to the mechanical lower limit position based on the fact that the operation of the actuator 60 has stopped. The control value is erroneously updated to a value different from the control value.

  Therefore, the valve operating control apparatus according to the present embodiment suitably suppresses such inconvenience by adopting the processing described below. Hereinafter, a processing procedure for executing control value learning will be described in detail with reference to the flowcharts of FIGS.

  A series of processes shown in FIGS. 7 and 8 are repeatedly executed by the microcomputer 70 with a predetermined control cycle. In this process, first, it is determined whether or not the learning condition flag Fg is “ON” (step S10). The initial value of the learning condition flag Fg is “off”, but this processing is performed when the predetermined learning condition is satisfied, for example, when the sensor characteristics of the position sensors S1 and S2 change. Set to “ON” through another process.

  When the learning condition flag Fg is “off” (step S10: NO), it is determined that the predetermined learning condition is not satisfied, and the series of processes is temporarily ended. On the other hand, when the learning condition flag Fg is “ON” (step S10: YES), it is determined whether or not the control interruption flag Fc is “ON” (step S20). The control interruption flag Fc is a flag that indicates whether or not a temporary stop of the control by the microcomputer 70 has occurred due to an instantaneous interruption of the power supply circuit of the microcomputer 70 in the previous control cycle. When a temporary stop occurs, “off” is set to “on” through a process different from this process.

When the control interruption flag Fc is “OFF” (step S20: NO), it is determined that the temporary stop of the control has not occurred, and the control value learning is executed.
In this control value learning process, first, the stroke count value S is calculated based on the following equation (1) based on the position count value P stored in the DRAM 72b and the initial value Sg stored in the EEPROM 72c (step S30). ). Further, the control target value St of the stroke count value is calculated through the following formula (2), and feedback control of the actuator control value is executed (step S40).

S ← Sg + P (1)
St ← SB (2)
B: Weight loss value

In equation (2), the weight loss value B is a positive value set in advance. Therefore, the control target value St is set to a value smaller than the stroke count value S, and the actuator 60 operates to the mechanical lower limit position. As a result, the control value of the actuator 60 decreases and the position count value P decreases.

  Next, the operation speed V of the actuator 60 in the current control cycle is calculated based on the change amount of the position count value P, and the change speed of the operation speed based on this and the operation speed Vz in the previous control cycle, that is, The acceleration W of the actuator 60 is calculated and stored in the DRAM 72b (step S50). Then, it is determined whether or not the operating speed V is smaller than the threshold value V0 (step S60). If the operating speed V is higher than the threshold value V0, it is determined that the actuator 60 is operating, the process returns to the previous step S30, and the control value learning is continuously executed. On the other hand, when the operating speed V is smaller than the threshold value V0, it is determined that the actuator 60 has reached the mechanical lower limit position, and the stroke count value S at that time is determined as the stroke count corresponding to the lower limit position stored in the ROM 72a. It is updated to a value (“0” in this embodiment) (step S70). Based on the updated stroke count value S and the initial value Sg, the position count value P is updated through the following equation (3) (step S80).

P ← S-Sg (3)

Then, the learning condition flag Fg is set to “off” (step S90), and this series of processes is temporarily ended.

  By the way, when the control interruption flag Fc is “ON” in the previous step S20 (step S20: YES), it is determined that the current control period is a control period immediately after the control returns from the interruption state, Processing corresponding to such interruption of control is executed.

  In this process, first, it is determined whether or not the acceleration W stored in the DRAM 72b in the cycle immediately before the interruption of control is smaller than the determination value W0 (step S21). This determination value W0 is the maximum value of the acceleration W when the actuator 60 operates to the mechanical lower limit position in the deformation region of the washer 67, and is detected by experiment and stored in the ROM 72a in advance. If the acceleration W is greater than or equal to the determination value W0 (step S21: NO), it is determined that the actuator 60 has not entered the deformation region of the washer 67, and control value learning (steps S30 to S90) is resumed. To do. On the other hand, if the acceleration W is smaller than the determination value W0 (step S21: YES), it is determined that the actuator 60 has entered the deformation region of the washer 67, and the position count value P stored in the DRAM 72b and the EEPROM 72c are stored. Based on the stored initial value Sg, the stroke count value S is calculated based on the above equation (1) (step S22). Then, the control target value St of the stroke count value is calculated through the following equation (4), and the feedback control of the control value of the actuator 60 is executed (step S23).

St ← SI (4)
I: Displacement amount

In the equation (4), the displacement amount I is the amount of change in the stroke count value S, that is, the deformation of the washer 67 during the period from when the washer 67 starts to be compressed by the reaction force of the driving force of the actuator 60 to the compression limit state. A value larger than the width of the area is set.

  After controlling the control value of the actuator 60 to the control target value St set based on the above equation (4), in other words, after the actuator 60 is surely operated outside the deformation region of the washer 67, the control interruption flag Fc Is set to “off” (step S24), and control value learning (steps S30 to S90) is resumed.

Hereinafter, a specific example of the control value learning process described above with reference to FIG. 9 will be described. FIG. 9 is a timing chart showing temporal transition of the control value of the actuator 60.
As shown in FIG. 9, at time T1, when a predetermined learning condition is satisfied during normal control in which no instantaneous interruption of the power feeding circuit of the microcomputer 70 occurs (step S10: YES), control value learning is performed. This is executed (steps S30 to S50), and the actuator 60 operates to its mechanical lower limit position, and the control value of the actuator 60 decreases.

  When an instantaneous interruption of the power supply circuit of the microcomputer 70 occurs at time T2, the control by the microcomputer 70 is temporarily stopped, and the operation of the actuator 60 is temporarily stopped. At time T3, when it is determined that the actuator 60 has entered the deformation region of the washer 67 when the control by the microcomputer 70 returns from the temporarily stopped state (step S21: YES), the control is performed. Processing corresponding to the interruption is executed (steps S22 to S24), and the actuator 60 is driven to the opposite side of the mechanical lower limit position.

  When the displacement amount of the actuator 60 reaches a displacement amount I set to a value larger than the width of the deformation region of the washer 67 at time T4, the control value learning is resumed. As shown in FIG. 9, when the control value learning is resumed in this way, the actuator 60 operates to a previous stop position with a predetermined operating inertia force.

According to the embodiment described above, the following effects can be obtained.
(1) When the actuator 60 is temporarily stopped during execution of the control value learning, the actuator 60 is operated to the opposite side of the mechanical limit position. Thus, for example, when the actuator 60 temporarily stops after the control value of the actuator 60 enters the deformation region of the washer 67 during execution of the control value learning process, the reaction force against the operation of the actuator 60 by the washer 67 is reduced. It can be lowered once. Then, when the control value learning is resumed under a state where the reaction force of the washer 67 is relatively small and the actuator 60 is operated to the mechanical limit position, the actuator 60 is operated to a previous stop position with a predetermined operating inertia force. be able to. Thereby, for example, when the control value learning is resumed directly from the stop position of the actuator 60, in other words, compared with the case where the actuator 60 is operated to the mechanical limit position under the state where the operation inertia force is “0”. Thus, the actuator 60 can be easily operated to the mechanical limit position. Therefore, even if the actuator 60 is temporarily stopped within the deformation region during execution of the control value learning, the actuator 60 reaches the mechanical limit position due to a decrease in the operating inertia force of the actuator 60. It can be suppressed. As a result, it is possible to prevent the control value from being erroneously updated depending on the operating state of the actuator 60.

  (2) The displacement amount I is set to a value larger than the width of the deformation region of the washer 67. Therefore, the actuator 60 can be reliably operated outside the deformation region of the washer 67. As a result, the control learning is resumed after the actuator 60 is operated to a position where the reaction force against the operation of the actuator 60 by the washer 67 is “0”. Can be effectively prevented from reaching the mechanical limit position.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the displacement amount I is set to a value larger than the width of the deformation region of the washer 67. However, for example, even if the actuator 60 starts to operate from a predetermined position in the deformation region, the mechanical lower limit is set. When the actuator can be operated to the position, the displacement amount I is not necessarily set to a value larger than the width of the deformation region.

  In the above embodiment, when the present invention is applied to a valve system control device that operates the actuator 60 to the mechanical lower limit position and updates the calculated value of the stroke count value S to the stroke count value corresponding to the lower limit position. It illustrated about. For example, when the actuator 60 is operated to the mechanical upper limit position, a washer that generates a reaction force against the operation of the actuator 60 is provided, and when the predetermined learning condition is satisfied, the actuator 60 is moved to the mechanical upper limit position. The present invention can also be applied basically in the same manner to a valve-operated control device that operates to a position and updates the calculated value of the stroke count value S to the stroke count value corresponding to the upper limit position.

  In the above embodiment, the case where the present invention is applied to the valve operating system of the internal combustion engine that feedback-controls the maximum lift amount of the intake valve 20 is illustrated, but in the valve operating system that feedback-controls the maximum lift amount of the exhaust valve 10 However, the present invention can be applied in basically the same manner.

1 is a cross-sectional view showing a partial cross-sectional structure of a valve train of an internal combustion engine according to an embodiment of the present invention. The top view which shows the arrangement | positioning aspect about the valve operating system of the internal combustion engine concerning the embodiment. The fracture | rupture perspective view which shows the internal structure about the mediation drive mechanism of the embodiment. The fragmentary sectional view which shows the control shaft of the same embodiment, an actuator, and a microcomputer. (A)-(h) The timing chart which shows the pattern change in which the output waveform of each sensor of the embodiment and the count value of each count change. (A), (b) The figure which shows the relationship between the output signal of each sensor of the same embodiment, an electrical angle count, and a position count. The flowchart which shows the process sequence about Lo end learning by the control apparatus of the embodiment. The flowchart which shows the process sequence about Lo end learning by the control apparatus of the embodiment. The timing chart which shows the time transition of the control value of the actuator of the embodiment.

Explanation of symbols

  C ... Coil, S1, S2 ... Position sensor, D1-D3 ... Electrical angle sensor, 2 ... Cylinder head, 10 ... Exhaust valve, 11 ... Valve spring, 12 ... Rush adjuster, 13 ... Rocker arm, 13a ... Roller, 14 ... Exhaust camshaft, 15 ... cam, 16 ... retainer, 20 ... intake valve, 21 ... valve spring, 22 ... lash adjuster, 23 ... rocker arm, 23a ... roller, 24 ... intake camshaft, 25 ... cam, 26 ... retainer, DESCRIPTION OF SYMBOLS 50 ... Mediation drive mechanism, 51 ... Input part, 51a ... Roller, 51h ... Helical spline, 52 ... Output part, 52h ... Helical spline, 53 ... Support pipe, 53a ... Long hole, 54 ... Control shaft, 55 ... Slider gear, 55a ... helical spline, 55b ... helical spline, 55c ... groove, 6 ... Bush, 56a ... Through hole, 57 ... Locking pin, 60 ... Electric actuator, 60a ... Housing, 60b, 60c ... Projection, 61 ... Motor, 61a ... Stator, 61b ... Rotor, 62 ... Planetary gear mechanism, 63: Output shaft, 63a, 63b ... Stopper, 64 ... Planetary gear, 65 ... Roller nut, 65a, 65b ... Stopper, 66 ... Bearing, 66a ... Outer ring, 66b, 66c ... Inner ring, 66d, 66e ... Ball, 67 ... Washer , 68 ... connecting member, 70 ... microcomputer, 71 ... central processing unit (CPU), 72a ... nonvolatile memory (ROM), 72b ... volatile memory (DRAM), 72c ... nonvolatile memory (EEPROM), 74 ... Accelerator sensor, 75 ... crank angle sensor, 90 ... exhaust valve device, 100 ... intake valve device.

Claims (2)

An actuator that changes a valve characteristic of an engine valve by operating within a mechanically regulated operating range, and when the actuator is operated to a mechanical limit position of the operating range in a deformation region; A change amount detection means for detecting a change amount from a predetermined initial value for a control value of the actuator, applied to a valve train provided with an elastic body that generates a reaction force against the operation of the actuator; and the initial value; The calculation means for calculating the control value of the actuator based on the change amount, and when a predetermined learning condition is satisfied, the actuator is operated to the mechanical limit position of the operating range, and the operation of the actuator is stopped. Sometimes the control value calculated by the calculating means is updated to a control value corresponding to the mechanical limit position. The control apparatus for valve system and a learning means for executing the control value learning,
When the actuator is temporarily stopped in the deformation area during the execution of the control value learning by the learning means, the control value learning by the learning means is performed after operating the actuator to the opposite side of the mechanical limit position. A valve operating system control device comprising learning resumption means for resuming operation. In the valve system control device according to claim 1,
The valve train control device, wherein the learning restarting means restarts the control value learning by the learning means after operating the actuator outside the deformation region of the elastic body.

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