JP2010025065A - Control device of valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a valve system capable of restraining the occurrence of a deviation between a detection value of a valve characteristic and an actual valve characteristic due to a change in the valve characteristic by energizing force of a valve spring after finishing control of the valve characteristic based on stopping of an internal combustion engine. <P>SOLUTION: This control device of the valve system capable of changing a maximum lift quantity of an intake valve 20, detects the maximum lift quantity based on a change history from a predetermined initial value and its initial value on the maximum lift quantity, and sets a control target value of the maximum lift quantity, and controls the maximum lift quantity by making a feedback process so that a detection value of the detected maximum lift quantity becomes small in separation from the control target value. The control device has a monitoring means for continuously detecting the maximum lift quantity after finishing feedback control of the maximum lift quantity based on the stopping of the internal combustion engine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is applied to a valve operating system capable of changing a valve characteristic of an engine valve, detects a change history from a predetermined initial value for the valve characteristic, and based on the detected change history and the initial value, the valve The present invention relates to a valve system control device for detecting characteristics.

  In recent years, in order to improve the fuel efficiency and output of an internal combustion engine, a valve operating system that changes valve characteristics such as the maximum lift amount and valve opening period of the engine valve based on the operating state of the internal combustion engine has been widely adopted ( For example, see Patent Document 1). The following configuration is generally adopted as such a valve train.

  That is, in this valve operating system, an input member that abuts on a cam rotated by an engine output shaft and swings based on the rotation, and an output member that reciprocates the engine valve by swinging together with the input member. And are provided. The engine valve is provided with a valve spring that urges the input member to the cam by urging the valve to the output member. The input member and the output member are mechanically connected to a control shaft capable of changing the relative oscillation phase difference between the input member and the output member by reciprocating in the axial direction. The base end is connected to the output shaft of the electric motor via a motion conversion mechanism. This motion conversion mechanism is for converting the rotational motion of the output shaft of the electric motor into linear motion in the axial direction of the control shaft, and its reverse efficiency is set low. In other words, the rotary motion of the output shaft of the electric motor can be easily changed to the linear motion of the control shaft, while the linear motion of the control shaft is prevented from being converted to the rotary motion of the output shaft of the electric motor. Has been. With this configuration, when the output shaft of the electric motor rotates, the control shaft is driven along the axial direction, and the relative phase difference between the input member and the output member is changed to change the maximum lift amount and the valve opening of the engine valve. Valve characteristics such as period are changed.

In such a valve operating system control apparatus, the valve characteristics of the engine valve are controlled in the following manner. That is, this control device is provided with a history sensor for detecting a rotation history of the output shaft of the electric motor, in other words, a history of change of the valve characteristic of the engine valve from a predetermined initial value. During engine operation, the valve system controller detects the valve characteristic based on the valve characteristic change history detected by the history sensor and its initial value, and controls the valve characteristic based on the engine operating state. By setting the target value and driving the electric motor, the valve characteristic is controlled so that the difference between the detected value of the valve characteristic and the control target value becomes small.
JP 2005-201117 A

  Thus, by changing the valve characteristic of the engine valve based on the engine operating state, the fuel efficiency performance and output of the internal combustion engine can be improved. However, as described above, the engine valve is urged to the output member by the urging force of the valve spring and the input member is urged to the cam, so that the relative oscillation phase difference between the input member and the output member is reduced. Torque to be generated, in other words, torque to drive the control shaft in the axial direction is always generated. Here, although the reverse efficiency of the motion conversion mechanism is set low, the control shaft is slightly driven by the torque described above, and the linear motion of the control shaft is rotated by the motion conversion mechanism of the output shaft of the electric motor. It cannot be denied that there is a possibility of conversion into movement. When the drive of the control shaft occurs in this way, the relative rocking phase difference between the input member and the output member changes, and the valve characteristics of the engine valve also change. In particular, when the frictional resistance between the drive members in the mechanism is reduced in order to increase the efficiency of the motion conversion mechanism, the reverse efficiency of the motion conversion mechanism is also increased, and this change in valve characteristics is more likely to occur. . Here, for example, if such a change in the valve characteristic occurs after the control of the valve characteristic is completed based on the stop of the internal combustion engine, the change history cannot be detected even though the actual valve characteristic has changed. After the start of the engine, a deviation occurs between the detected value of the valve characteristic and the actual valve characteristic. As a result, the accuracy of control of the valve characteristics may be reduced.

  In addition, although the valve system control device has been described that employs a motion conversion mechanism that converts the rotational motion of the electric motor to the linear motion of the control shaft as an actuator that changes the valve characteristics, such inconvenience is limited to the same configuration. In addition, it can occur almost in common in a valve system control device that employs other types of actuators.

  The present invention has been made in view of such circumstances, and its purpose is that the valve characteristics change due to the urging force of the valve spring after the control of the valve characteristics is completed based on the stop of the internal combustion engine. An object of the present invention is to provide a valve operating system control device capable of suppressing the occurrence of a deviation between a detected value of a valve characteristic and an actual valve characteristic.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is an input member that abuts on a cam of an internal combustion engine and swings based on rotation thereof, an output member that reciprocates an engine valve by swinging together with the input member, and the engine valve A valve spring for urging the input member to the cam by urging the output member to the output member, and a relative swing phase difference between the input member and the output member mechanically connected to the input member and the output member. Is applied to a valve train system including an actuator capable of changing the valve characteristic of the engine valve by changing the engine valve, and a change history from a predetermined initial value is detected for the valve characteristic, and the detected change history and the A valve characteristic detecting means for detecting the valve characteristic based on an initial value, and a control target value for the valve characteristic is set and detected by the valve characteristic detecting means. In a valve system control device comprising: valve characteristic control means for performing valve characteristic control for changing the valve characteristic through the actuator so that a deviation between a detected value of the valve characteristic and the control target value is small. The gist of the present invention is to include monitoring means for continuously detecting the valve characteristic by the valve characteristic detection means after the valve characteristic control by the valve characteristic control means is completed based on the stop of the engine.

  According to this configuration, the valve characteristic is continuously detected after the valve characteristic control is ended based on the stop of the internal combustion engine, and the input member and the output member are thereby detected by the urging force of the valve spring after the valve characteristic control is completed. Even when the relative oscillation phase difference is changed and the valve characteristic changes, the valve characteristic can be accurately detected based on the change history of the valve characteristic. For this reason, for example, compared to a case where the detection of the valve characteristic is stopped on the condition that the valve characteristic control is completed, the valve characteristic of the engine valve is increased by the biasing force of the valve spring after the control of the valve characteristic is completed. It is possible to suppress the occurrence of a deviation between the detected value of the valve characteristic and the actual valve characteristic due to the change.

  According to a second aspect of the present invention, in the valve operating control apparatus according to the first aspect, when a predetermined time elapses after the valve characteristic control by the valve characteristic control means ends, the valve characteristic control is performed. The gist of the present invention is to stop the detection of the valve characteristic by the monitoring means on the condition that the valve characteristic has not changed between the end of the process and the present time.

  According to a third aspect of the present invention, in the valve operating control apparatus according to the second aspect, when the predetermined time elapses after the valve characteristic control by the valve characteristic control means is finished, On the condition that the valve characteristic has changed between the end of the control and the current time point, the detection of the valve characteristic by the monitoring means is stopped, and the detected value of the valve characteristic and the actual value are detected at the next engine start. The gist is to perform valve characteristic learning that eliminates the deviation from the valve characteristic.

  When valve characteristic control is executed during operation of the internal combustion engine, dynamic frictional force is generated at the sliding portion of each member in the valve system, but the valve characteristic control ends when the internal combustion engine stops. Then, the driving of the valve operating system stops, and the frictional force between the sliding members in the valve operating system becomes a static frictional force, so that the resistance force to the driving of the valve operating system increases. Therefore, when the drive of the valve system is temporarily stopped and stabilized at the end of the valve characteristic control, the change of the relative oscillation phase difference occurs due to the urging force of the valve spring until the next engine start. In other words, there is a low possibility that a change in valve characteristics will occur.

  Therefore, according to the second aspect of the present invention, the valve characteristic does not change between the end of the valve characteristic control by the valve characteristic control means and the elapse of a predetermined time, in other words, the valve characteristic. By stopping the detection of the valve characteristics by the monitoring means on the condition that the driving of the valve system is once stopped and stabilized at the end of the control, the valve characteristics can be changed during a period when the change of the valve characteristics is unlikely to occur. An increase in power consumption due to detection can be avoided.

  By the way, even when a change in the valve characteristic has occurred between the end of the valve characteristic control and the elapse of a predetermined time, if the detection of the valve characteristic by the monitoring means is simply stopped as described above, Thereafter, the valve characteristic continuously changes, and there is a possibility that a deviation occurs between the detected value of the valve characteristic and the actual valve characteristic.

  In this regard, in the invention according to claim 3, the monitoring means by the monitoring means is provided on the condition that the valve characteristics have changed from the end of the valve characteristic control by the valve characteristic control means to the elapse of a predetermined time. The detection of the valve characteristic is stopped, and the valve characteristic learning for eliminating the deviation between the detected value of the valve characteristic and the actual valve characteristic at the next engine start is performed. As a result, even if the valve characteristic continuously changes after the detection of the valve characteristic by the monitoring unit is stopped, the valve characteristic learning value at the next engine start is performed, so that the detected value of the valve characteristic and the actual value are detected. The deviation from the valve characteristics can be eliminated. Therefore, according to the above configuration, it is possible to suppress the occurrence of a deviation between the detected value of the valve characteristic and the actual valve characteristic, while suppressing the power consumed to detect the valve characteristic. .

  When an actuator that operates between two mechanical limit positions is employed, as a specific method of valve characteristic learning, for example, as described in claim 4, the actuator may be connected to the mechanical limit. The actuator is operated toward one of the positions, and when the actuator is stopped, it is determined that the actuator has been operated to the mechanical limit position, and the valve characteristic at the time is changed to the value corresponding to the mechanical limit position. A configuration in which the reference value is set can be employed.

  Hereinafter, an embodiment in which the present invention is applied to a control device for a valve operating system 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 of the valve operating system of the internal combustion engine. is there.

  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 in a compressed state. 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 a 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.

  On the other hand, the intake valve opening / closing device 100 is provided with a compressed 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 includes an input member 51 and a pair of output members 52, and the input member 51 and the output member 52 are swingably supported by a support pipe 53 fixed to the cylinder head 2. . The intake valve 20 and the rocker arm 23 are urged toward the output member 52 by the urging force of the valve spring 21, and a roller 23 a provided at an intermediate portion of the rocker arm 23 is in contact with the outer peripheral surface of the output member 52. . As a result, the input member 51 is urged to swing in the counterclockwise direction W <b> 1 together with the output member 52, and the roller 51 a provided at the tip of the radially extending portion of the input member 51 presses the outer peripheral surface of the cam 25. Is done. That is, a torque for reducing the relative oscillation phase difference between the input member 51 and the output member 52 is always generated by the urging force of the valve spring 21.

  In such an intake valve opening / closing device 100, when the cam 25 rotates during engine operation, the cam 25 presses the input member 51 while being in sliding contact with the roller 51a, whereby the output member 52 swings in the circumferential direction of the support pipe 53. It becomes like this. When the output member 52 swings, the rocker arm 23 swings about 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.

  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 member 51 and the output member 52 via a connecting member. When the control shaft 54 is driven along the axial direction, the input member 51 and the output member 52 are relatively swung. Note that, as described above, since the torque for reducing the relative rocking phase difference between the input member 51 and the output member 52 is always generated by the urging force of the valve spring 21, the control shaft 54 includes the control shaft 54. A torque is always generated to drive the motor in the axial direction.

  Next, the intermediary drive mechanism 50 that connects the control shaft 54, the input member 51, and the output member 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 member 51 is provided between a pair of output members 52, and a substantially cylindrical communication space is formed inside the input member 51 and the output member 52. In addition, a helical spline 51h is formed on the inner peripheral surface of the input member 51, and a helical spline 52h in which the helical spline 51h of the input member 51 and its teeth are inclined in the opposite direction are formed on the inner peripheral surface of the output member 52. Is formed.

  In a space formed inside the input member 51 and the output member 52, a substantially cylindrical slider gear 55 is provided. A helical spline 55a that meshes with the helical spline 51h of the input member 51 is formed at the center 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 member 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 engaged with the helical splines 51h and 52h formed on the inner peripheral surfaces of the input member 51 and the output member 52, respectively. When displaced in the axial direction, the input member 51 and the output member 52 rotate in opposite directions. As a result, the relative phase difference between the input member 51 and the output member 52 is changed, and the maximum lift amount of the intake valve 20 and the operating angle corresponding to the valve opening period of the intake valve 20 are changed. FIG. 4 is a graph showing how the maximum lift amount and the operating angle of the intake valve 20 change according to the change in the relative phase difference between the input member 51 and the output member 52. As shown in FIG. 4, the maximum lift amount and the operating angle of the intake valve 20 increase as the relative phase difference between the input member 51 and the output member 52 increases. Note that when the relative phase difference between the input member 51 and the output member 52 changes, the maximum lift amount and the operating angle of the intake valve 20 change corresponding to each other. Only that will be described.

  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. 5 is a partial cross-sectional view mainly showing the structure of the actuator 60.

  As shown in FIG. 5, 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 motion conversion mechanism for converting the rotation of the rotor 61b into a linear motion and transmitting it to the control shaft 54. 62 is provided. The motion conversion mechanism 62 is set to have a low reverse efficiency. That is, by the same motion conversion mechanism 62, the rotational motion of the rotor 61b can be easily changed to the linear motion of the control shaft 54, while the linear motion of the control shaft 54 is suppressed from being converted into the rotational motion of the rotor 61b. .

  This motion conversion mechanism 62 has an output shaft 63 provided with a spiral spline on the outer periphery, and 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 displaceable in the axial direction and not to rotate about the axis L, and the tip end portion (the left end portion in FIG. 5) 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.

  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. The energization of the coil C is duty-controlled by the microcomputer 70 based on the operating state of the engine. 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 is driven in the direction F of FIG. 5, the maximum lift amount decreases, while when the control shaft 54 is driven in the direction R of FIG. 5, the maximum lift amount increases. The output shaft 63 is fixed with two stoppers 63a and 63b that can come into contact with the housing 60a. The output shaft 63, in other words, the control shaft 54, is driven by the stoppers 63a and 63b. Can be driven. When the output shaft 63 is displaced to a mechanical limit position where the stopper 63a contacts the housing 60a (hereinafter referred to as “Hi end”), the maximum lift amount becomes the maximum value, while the stopper 63b contacts the housing 60a. When the output shaft 63 is displaced to the mechanical limit position (hereinafter referred to as “Lo end”), the maximum lift amount becomes the minimum value.

  As shown in FIG. 5, the actuator 60 includes three electrical angle sensors D1 to D3, and an 8-pole multipolar magnet that rotates integrally with the roller nut 65 in correspondence with the electrical angle sensors D1 to D3. Is provided. These electrical angle sensors D1 to D3 are pulse-like signals as shown in FIGS. 6A to 6C, that is, a logic high level signal “H” and a logic low, according to 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. 6D and 6E, 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 the memory, and a rewritable nonvolatile memory (EEPROM) 72c for storing the reference value obtained by the learning control. Further, the microcomputer 70 is connected with sensors for detecting the operating state of the engine, such as a current sensor 73 for detecting a current flowing through the coil C and an accelerator sensor 74 for detecting an opening degree of an accelerator pedal of the vehicle.

  The microcomputer 70 is in a state in which the control operation can be executed by receiving power from the in-vehicle battery BT via the main relay MR maintained in the on state based on the on operation of the ignition switch IG. In other words, when the ignition switch IG is turned on, the microcomputer 70 turns on the internal setting of the main relay MR to take in the voltage VB of the in-vehicle battery BT, and the microcomputer 70 and the internal combustion engine are based on the voltage VB. A voltage for driving each electric drive unit is generated. When the ignition switch IG is turned off, the microcomputer 70 finishes each post-processing and then turns off the internal setting of the main relay MR to cut off the power supply from the in-vehicle battery BT to the microcomputer 70.

  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 maximum lift amount of the intake valve 20 is detected. Hereinafter, the procedure for detecting the maximum lift amount of the intake valve 20 will be described in detail with reference to FIGS. 6 and 7.

  Here, FIGS. 6A to 6E 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. 6 (f) to 6 (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. . 7A 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. 7B 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. 7A, depending on which of the logic high level signal “H” and 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 change history from the initial value at the time of starting the engine with respect to the operating angle of the motor 61, in other words, the maximum lift amount of the intake valve 20, and is stored in the DRAM 72b. 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 of “L” is output, either “+1” or “−1” is added to the position count value P (see FIG. 7B). In FIG. 7B, “↑” 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. 6 (d) and 6 (e). Then, the pattern changes in the direction indicated by the arrow A along the pattern shown in FIG. On the other hand, if the actuator 60 is in reverse rotation, 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.

[Stroke count value S]
The stroke count value S represents the maximum lift amount of the intake valve 20. During engine operation, 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. Note that after the detection of the position count value P is completed based on the stop of the internal combustion engine, the final value of the stroke count value S when the drive of the intake valve opening / closing device 100 is stopped is the initial value Sg at the start of the next engine operation. And stored in the EEPROM 72c.

  Therefore, the microcomputer 70 detects the stroke count value S, that is, 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. Then, the microcomputer 70 sets the duty ratio DU of energization to the actuator 60, in other words, the actuator 60 so that the deviation between the detected value of the maximum lift amount and the control target value set based on the engine operating state becomes small. The maximum lift amount is feedback controlled by changing the driving load. Hereinafter, control of the duty ratio of energization to the actuator 60 will be described in detail.

  In the processing related to the feedback control of the maximum lift amount (hereinafter simply referred to as “feedback control”), the duty ratio DU is less than or equal to the deviation ΔRVL between the control target value of the maximum lift amount of the intake valve 20 and the detected value thereof. These are set through the arithmetic expressions (1) to (4).

DU ← VLP + VLI + VLD (1)

VLP ← KP ・ ΔRVL (2)
KP: Correction coefficient (proportional gain)

VLI ← KI · ΣΔRVL (i) (3)
KI: Correction coefficient (integral gain)

VLD ← KD · (ΣΔRVL (i) −ΣΔRVL (i−1)) / Δt (4)
KD: Correction coefficient (differential gain)
Δt: Control cycle

In the above equation (2), “VLP” is a proportional term in the feedback control, and when there is no deviation tendency between the detected value of the maximum lift amount of the intake valve 20 and its control target value, This proportional term VLP converges to its initial value “0”.

  On the other hand, when the detected value of the maximum lift amount of the intake valve 20 is smaller than the control target value, the proportional term VLP is set to a positive value, and the driving load that biases the control shaft 54 in the direction R in FIG. Occurs.

  On the other hand, when the detected value of the maximum lift amount of the intake valve 20 is larger than the control target value, the proportional term VLP is set to a negative value, and the driving load that biases the control shaft 54 in the direction R in FIG. Occurs.

  Thus, based on the deviation ΔRVL between the detected value of the maximum lift amount and the control target value, the proportional term VLP having a size corresponding to the deviation ΔRVL is calculated, so that it is between the detected value of the maximum lift amount and the control target value. The duty ratio DU is set to an appropriate amount so as to compensate for the deviation.

  In the above equation (3), “VLI” is an integral term in the feedback control. In the above equation (3), “ΣΔRVL” is an integrated value of the deviation ΔRVL in a predetermined period, and the subscript “i” is a value of the deviation ΔRVL calculated in each control cycle in the predetermined period. Respectively. As apparent from the equation (3), when there is a steady deviation between the control target value of the maximum lift amount and the detected value, the integral term VLI gradually increases or decreases. As a result, even if there is a steady deviation between the control target value of the maximum lift amount and the detected value that cannot be compensated for by the proportional term VLP, this deviation is caused by this integral term VLI. Will be countered.

  In the above equation (4), “VLD” is a differential term. As shown in the equation (4), when the deviation ΔRVL between the detected value of the maximum lift amount and the control target value changes abruptly, the differential term VLD changes so as to moderate the change.

  As a result, by such feedback control, as the resistance load for driving the actuator 60 increases, the duty ratio DU of energization to the actuator 60 is set larger, and the current flowing through the actuator 60, more precisely the coil C, increases.

  By such feedback control, 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. In the conventional valve system control device, the feedback control is terminated based on the stop of the internal combustion engine, the detection of the position count value P is stopped, and the final value of the stroke count value S is set at the start of the next engine operation. Is learned as an initial value Sg and stored in the EEPROM 72c.

  However, as described above, the torque for driving the control shaft 54 in the axial direction is always generated by the biasing force of the valve spring 21. Here, although the reverse efficiency of the motion conversion mechanism 62 is set low, the control shaft 54 is slightly driven by the torque described above, and the linear motion of the control shaft 54 is rotated by the motion conversion mechanism 62 to rotate the rotor 61b. It cannot be denied that there is a possibility of conversion into movement. When the control shaft 54 is thus driven, the relative swing phase difference between the input member 51 and the output member 52 changes, and the maximum lift amount of the intake valve 20 also changes. In particular, when the frictional resistance between the drive members in the mechanism is reduced in order to increase the efficiency of the motion conversion mechanism 62, the reverse efficiency of the motion conversion mechanism 62 is also increased, and this change in the maximum lift is more likely to occur. It becomes easy to do. Here, for example, when such a change in the maximum lift amount occurs after the feedback control is completed based on the stop of the internal combustion engine, the change history cannot be detected even though the actual maximum lift amount has changed. After the start of the engine, a deviation occurs between the detected value of the maximum lift amount and the actual maximum lift amount. As a result, the accuracy of control of the maximum lift amount may be reduced.

  Therefore, in the present embodiment, after the internal combustion engine is stopped, the following monitoring process is executed as a post-processing of the feedback control described above, thereby causing a deviation between the detected value of the maximum lift amount and the actual maximum lift amount. I try to suppress it.

  Hereinafter, the procedure of the monitoring process according to the present embodiment will be described with reference to the flowchart of FIG. A series of processing shown in FIG. 8 is executed by the microcomputer 70 when the internal combustion engine is started.

  In this process, first, it is determined whether or not the feedback control of the maximum lift amount is completed based on the engine stop (step S10). Here, when it is determined that the feedback control has not ended (step S10: NO), the determination in step S10 is repeatedly performed at a predetermined time interval. On the other hand, when it is determined that the feedback control is completed based on the engine stop (step S10: YES), the position count value P is continuously detected, and the stroke count is determined based on the detected position count value P. The value S is updated (step S20).

  Then, it is determined whether or not a predetermined time T has elapsed since the above-described feedback control has been completed (step S30). The predetermined time T is set to a time shorter than the time required for other post-processing, and is stored in the EEPROM 72c. Here, when it is determined that the predetermined time T has not elapsed since the feedback control has ended (step S30: NO), the process of step S20 is repeatedly executed. On the other hand, when it is determined that the predetermined time T has elapsed since the feedback control has ended (step S30: YES), it is determined whether or not the stroke count value S has changed after the feedback control has ended (step S40). ).

  When it is determined that the stroke count value S has changed after the feedback control is completed (step S40: YES), the learning flag Fg is set to “on” (step S50), and this series of processes is temporarily ended.

  Here, the learning flag Fg is a flag that indicates whether or not it is necessary to perform maximum lift amount learning that eliminates the deviation between the detected value of the maximum lift amount and the actual maximum lift amount at the next engine start. The value is stored in the EEPROM 72c. The maximum lift amount learning will be described later.

  On the other hand, when it is determined that the stroke count value S has not changed after the feedback control is completed (step S40: NO), the valve system drive is temporarily stopped and stabilized with the completion of the feedback control. It is determined that there is a low possibility that a change in the maximum lift amount of the intake valve 20 will occur due to the urging force of the valve spring 21 before the engine is started. In this case, the learning flag Fg is set to “off” (step S51), and this series of processing ends.

  Incidentally, after the internal combustion engine is stopped, when all the post-processes including the monitoring process described above are completed, the main relay MR is turned off, and the power supply from the in-vehicle battery BT to the microcomputer 70 is interrupted.

  Next, the processing procedure of the maximum lift amount learning that is executed when the engine is started will be described with reference to the flowchart of FIG. The series of processing shown in FIG. 9 is executed by the microcomputer 70 when the internal combustion engine is started.

  In this process, first, it is determined whether or not the learning flag Fg set in the previous monitoring process when the engine is stopped is “ON” (step S110). When the learning flag Fg is “OFF” (step S110: NO), it is determined that there is a low possibility that the maximum lift amount of the intake valve 20 will change after the previous feedback control is completed, and the maximum lift amount is determined. This series of processes is temporarily terminated without executing learning.

  On the other hand, when the learning flag Fg is “ON” (step S110: YES), based on the stroke count value S detected at that time, that is, the detected value Sk of the stroke count value S, the following equation (5) Then, the control target value St of the stroke count value S is calculated through the above-described feedback control (step S120).

St ← Sk−Bd (5)
Bd: Weight loss value

In equation (5), the weight loss value Bd is a positive value set in advance. Therefore, the control target value St is set to a value smaller than the detected value Sk of the stroke count value S, and the control shaft 54 is driven so as to be displaced toward the Lo end side. As a result, the maximum lift amount decreases and the position count value P decreases. It should be noted that the amount of reduction Bd is set as appropriate in order to suppress a sudden change in the maximum lift amount.

  Next, it is determined whether or not the stroke count value S cannot be changed (step S130). Specifically, for example, when the detection value Sk of the stroke count value S does not change even though the current flowing through the duty ratio DU and the actuator 60 is larger than a predetermined threshold, the stroke count value S cannot be changed. It is possible to adopt a method such as judging that it has become.

  Here, when it is determined that the maximum lift amount can be changed (step S130: NO), it is determined that the control shaft 54 has not reached the Lo end, and the process returns to the previous step S120 to control the control shaft. 54 is continuously driven to the Lo end side. On the other hand, if it is determined that the maximum lift amount cannot be changed (step S130: YES), it is determined that the control shaft 54 has reached the Lo end, and the detected value Sk of the stroke count value S at that time is determined. Is updated to the reference value Slo of the stroke count value corresponding to the Lo end stored in the EEPROM 72c, and the position count value P is reset to “0” (step S150).

  Hereinafter, a specific example of the monitoring process and the maximum lift amount learning will be described with reference to FIG. FIG. 10A shows the time of the stroke count value S when the stroke count value S is not converted after the feedback control is finished. FIG. 10B shows the time of the stroke count value S when the stroke count value S changes after the feedback control is finished. 6 is a timing chart showing typical transitions.

  As shown in FIG. 10 (a), when the feedback control is terminated based on the stop of the internal combustion engine at time t0 (step S10: YES), the position count value P is continuously detected and the stroke count value is detected. S is updated (step S20).

  Then, when the predetermined time T has elapsed after the feedback control is finished at time t1 (step S30: YES), it is determined whether or not the stroke count value S has changed after the feedback control is finished (step S40).

  For example, as shown in FIG. 10 (a), when it is determined that the stroke count value S has not changed after the feedback control is completed (step S40: NO), the valve is not used until the next engine start. It is determined that the maximum lift amount of the intake valve 20 is unlikely to change due to the urging force of the spring 21, and the learning flag Fg is set to “off” (step S51), and the monitoring process is terminated. Incidentally, when all the post-processes including this monitoring process are completed at time t2, the main relay MR is turned off and the power supply from the in-vehicle battery BT to the microcomputer 70 is cut off.

  When the internal combustion engine is started again at time t3, the learning flag Fg is set to “off” (step S110: NO), so that the maximum lift amount learning is not executed and normal feedback control is started.

  On the other hand, as shown in FIG. 10B, when a predetermined time T has elapsed after the feedback control has ended (time t1), it is determined that the stroke count value S has changed (step S40: YES), the learning flag Fg is set to “ON” (step S50), and the monitoring process is terminated.

  Here, as shown in FIG. 10B, the detection value Sk of the stroke count value S is maintained at the final value at the end of the process (time t1) with the end of the monitoring process. The actual stroke count value S may continuously change due to the biasing force of the spring 21.

  However, when the internal combustion engine is started again at time t3, the learning flag Fg is set to “ON” at the end of the monitoring process (step S110: YES), so that the maximum lift amount learning is executed. That is, the control shaft 54 is driven so as to be displaced toward the Lo end side (step S120), and when it is determined that the control shaft 54 has reached the Lo end at time t4 (step S130: YES), the stroke count at that time is determined. The detection value Sk of the value S is updated to the reference value Slo of the stroke count value corresponding to the Lo end stored in the EEPROM 72c, and the position count value P is reset to “0” (step S140). Thereafter, normal feedback control is started.

According to the embodiment described above, the following effects can be obtained.
(1) The stroke count value S, in other words, the maximum lift amount is continuously detected after the feedback control of the maximum lift amount is completed based on the stop of the internal combustion engine. Thereby, even when the maximum lift amount is changed even after the feedback control is completed and the relative swing phase difference between the input member 51 and the output member 52 is changed by the biasing force of the valve spring 21, the maximum lift amount is changed. Can be accurately detected. Therefore, for example, the maximum lift amount is changed by the urging force of the valve spring 21 after the feedback control is completed, as compared with the case where the configuration in which the detection of the maximum lift amount is stopped on the condition that the feedback control is ended is employed. Due to this, it is possible to suppress the occurrence of a deviation between the detected value of the maximum lift amount and the actual maximum lift amount.

  (2) Maximum by the urging force of the valve spring 21 until the next engine start, on the condition that the maximum lift amount has not changed from when the feedback control is finished until the predetermined time T elapses. The detection of the maximum lift amount was stopped because it was judged that the possibility of a change in the lift amount was low. Here, when feedback control is executed during operation of the internal combustion engine, dynamic friction force is generated at the sliding portion of each member in the valve operating system, but the feedback control is performed based on the stop of the internal combustion engine. When is finished, the driving of the valve system is stopped, and the frictional force between the sliding members in the valve system becomes a static frictional force, so that the resistance force to the driving of the valve system is increased. Therefore, if the driving of the valve system is temporarily stopped and stabilized with the end of the feedback control, the maximum lift amount may change due to the urging force of the valve spring 21 until the next engine start. Is low. Therefore, according to the above configuration, the maximum lift amount does not change between the end of the feedback control and the elapse of the predetermined time T, in other words, the driving of the valve train with the end of the maximum lift amount. By stopping the detection of the maximum lift amount on the condition that the vehicle has stopped once and stabilized, it is possible to avoid detecting the maximum lift amount during a period in which the change in the maximum lift amount is unlikely to occur. Therefore, after the internal combustion engine is stopped, it is possible to suppress delaying the power supply to the microcomputer 70 by the monitoring process, and it is possible to suppress the power consumed to detect the maximum lift amount as much as possible.

  (3) The detection of the maximum lift amount is stopped on the condition that the maximum lift amount has changed between the end of the feedback control and the elapse of the predetermined time T, and the maximum lift amount is detected at the next engine start. The maximum lift amount learning that eliminates the deviation between the actual value and the actual maximum lift amount is performed. Thus, even if the maximum lift amount continues to change after the detection of the maximum lift amount is stopped, the maximum lift amount is detected by performing the maximum lift amount learning at the next engine start. Deviations from the actual maximum lift amount can be eliminated. Therefore, according to the above configuration, it is possible to suppress the occurrence of a deviation between the detected value of the maximum lift amount and the actual valve characteristic while suppressing the electric power consumed for detecting the maximum lift amount.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the maximum lift amount learning is performed at the next engine start, on the condition that the stroke count value S, that is, the maximum lift amount has changed between the completion of the feedback control and the elapse of the predetermined time T. Like to do. Here, when the maximum lift amount changes due to the urging force of the valve spring 21 after the feedback control is completed, the urging force of the valve spring 21 tends to decrease with the change in the maximum lift amount. When the urging force of the valve spring 21 becomes smaller than a predetermined threshold value, the change in the maximum lift amount stops. Therefore, by adopting a configuration in which the predetermined time T is set to a time longer than the longest time until the change in the maximum lift amount due to the urging force of the valve spring 21 stops, the maximum lift amount is reduced after the feedback control is completed. Even if there is a change, the change can be detected accurately, and the maximum lift amount learning at the next engine start may be omitted.

  In addition, for example, when the stroke count value S changes after the feedback control is completed, a configuration may be adopted in which the stroke count value S is continuously detected until the change of the stroke count value S stops. Specifically, as shown in the flowchart of FIG. 11, after the feedback control is ended based on the stop of the internal combustion engine (step S210: YES), the position count value P is continuously detected, and the stroke count value S is detected. Is updated (step S220). Then, it is determined whether or not the change of the stroke count value S is stopped (step S230). When the change of the stroke count value S is not stopped (step S230: NO), the detection process in step S220 is repeatedly executed, while when the change of the stroke count value S is stopped (step S230: YES). ), This series of processes is temporarily terminated. By adopting such a configuration, even when the maximum lift amount changes after feedback control is completed, the change can be detected accurately, so the maximum lift amount learning at the next engine start is omitted. You can also

  In the above embodiment, the predetermined time T is set to a time shorter than the time required for other post-processing. However, the present invention is not limited to this, and the maximum lift after the feedback control ends with higher reliability. In order to detect the presence or absence of a change in amount, the predetermined time T may be set to a time longer than the time required for other post-processing. Further, when post-processing other than the above-described monitoring processing is not executed, the predetermined time T can be set to a time that can ensure sufficient reliability for detecting the presence or absence of the maximum lift amount change.

  In the above-described embodiment, when the maximum lift amount changes between the end of the feedback control and the elapse of the predetermined time T, the control shaft 54 is driven to the Lo end at the next engine start, and at that time The detection value Sk of the stroke count value S is updated to the reference value Slo corresponding to the Lo end. On the other hand, the control shaft 54 may be driven to the Hi end when the engine is started, and the detected value Sk of the stroke count value S at that time may be updated to the reference value Shi corresponding to the Hi end.

  In the above-described embodiment, the case where the present invention is applied to a valve-operated control device that changes the maximum lift amount and the operating angle of the intake valve 20 based on the engine operating state has been illustrated, but the maximum lift amount of the exhaust valve 10 The present invention can also be applied in basically the same manner to a valve operating system control device that changes the operating angle. Further, the present invention can be applied not only to the maximum lift amount and operating angle of the engine valve, but also to a valve operating system controller that changes other valve characteristics that can be changed by the urging force of the valve spring when the engine is stopped.

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 graph which shows the change aspect of the maximum lift amount and working angle of an intake valve accompanying the change of the relative phase difference of the input member and output member of the embodiment. The fragmentary sectional view which mainly shows the structure of the actuator of the embodiment. (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 the monitoring process concerning the embodiment. The flowchart which shows the process sequence about the maximum lift amount learning concerning the embodiment. (A), (b) The timing chart which shows a specific example of the time transition of a stroke count value, when the monitoring process and maximum lift amount learning concerning the embodiment are performed. The flowchart which shows the process sequence about the modification of the said monitoring process.

Explanation of symbols

  BT ... In-vehicle battery, C ... Coil, IG ... Ignition switch, MR ... Main relay, S1, S2 ... Position sensor, D1-D3 ... Electric 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 ... Rush adjuster, 23 ... Rocker arm, 23a ... Roller 24 ... intake camshaft, 25 ... cam, 26 ... retainer, 50 ... intermediate drive mechanism, 51 ... input member, 51a ... roller, 51h ... helical spline, 52 ... output member, 52h ... helical spline, 53 ... support pipe, 53a ... long hole, 54 ... control shaft, 55 ... slider A, 55a ... helical spline, 55b ... helical spline, 55c ... groove, 56 ... bush, 56a ... through hole, 57 ... locking pin, 60 ... actuator, 60a ... housing, 61 ... motor, 61a ... stator, 61b ... rotor 62 ... motion conversion mechanism, 63 ... output shaft, 63a, 63b ... stopper, 64 ... planet gear, 65 ... roller nut, 66 ... bearing, 68 ... connecting member, 70 ... microcomputer (valve characteristic detecting means, valve characteristic) Control means, monitoring means), 71 ... central processing unit (CPU), 72a ... non-volatile memory (ROM), 72b ... volatile memory (DRAM), 72c ... non-volatile memory (EEPROM), 73 ... current sensor, 74 Accelerator sensor 90 Exhaust valve opening / closing mechanism 100 Intake valve opening / closing mechanism

Claims (4)

An input member that contacts the cam of the internal combustion engine and swings based on the rotation thereof, an output member that reciprocates the engine valve by swinging together with the input member, and urges the engine valve to the output member And a valve spring for urging the input member to the cam, and mechanically connected to the input member and the output member, and by changing a relative oscillation phase difference between the input member and the output member, Applied to valve trains with actuators that can change valve characteristics,
A change history from a predetermined initial value for the valve characteristic is detected, and a valve characteristic detection means for detecting the valve characteristic based on the detected change history and the initial value, and a control target value for the valve characteristic is set. And valve characteristic control means for executing valve characteristic control for changing the valve characteristic through the actuator so that the deviation of the detected value of the valve characteristic detected by the valve characteristic detection means from the control target value is reduced. In the valve train control device provided,
Control of a valve train system comprising: monitoring means for continuously detecting the valve characteristic by the valve characteristic detection means after the valve characteristic control by the valve characteristic control means is completed based on the stop of the internal combustion engine. apparatus. In the valve system control device according to claim 1,
On the condition that when the predetermined time has elapsed since the end of the valve characteristic control by the valve characteristic control means, the valve characteristic has not changed between the end of the valve characteristic control and the present time. The control of the valve operating system is characterized in that detection of the valve characteristic by the monitoring means is stopped. In the valve system control device according to claim 2,
When the predetermined time has elapsed since the end of the valve characteristic control by the valve characteristic control means, on the condition that the valve characteristic has changed between the end of the valve characteristic control and the present time, Control of the valve operating system characterized by stopping the detection of the valve characteristic by the monitoring means, and performing valve characteristic learning to eliminate the deviation between the detected value of the valve characteristic and the actual valve characteristic at the next engine start apparatus. In the valve system control device according to claim 3,
The actuator operates between two mechanical limit positions, and the valve characteristic learning operates the actuator toward one of the mechanical limit positions, and when the actuator stops, the actuator The valve characteristic at the time is set to the reference value of the valve characteristic corresponding to the mechanical limit position. apparatus.

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