JP4665937B2 - Valve control system - Google Patents

Description

  The present invention includes an opening / closing device that opens and closes an engine valve based on a rotational force of an output shaft of an internal combustion engine, and an actuator mechanically linked to the opening / closing device, and the opening / closing device is driven via the actuator. The present invention relates to a valve operating system control device that can change the maximum lift amount of an engine valve.

  In recent years, in order to improve the fuel consumption and output of an internal combustion engine, a valve operating system for the internal combustion engine that changes the maximum lift amount of the engine valve based on the engine operating state has been adopted. As such a valve operating system, for example, one described in Patent Document 1 is known. In the apparatus described in this document, 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. I have. The cam, the input member and the output member constitute an opening / closing device that opens and closes the engine valve. A control shaft is drivingly connected to the input member and the output member, and an output shaft of an actuator that drives the control shaft is connected to a base end portion of the control shaft. When the control shaft is driven by this actuator, the relative phase difference between the input member and the output member is changed, and the maximum lift amount of the engine valve is changed.

  Such a valve operating system control the maximum lift amount of the engine valve in the following manner. In other words, this control device is provided with a sensor for detecting a change history of the actuator operation amount, in other words, a change history from a predetermined initial value for the maximum lift amount of the engine valve. During engine operation, the memory cell of the volatile memory of the microcomputer is charged / discharged to store the change history detected by the sensor in the volatile memory. In addition, the microcomputer calculates an actual value of the maximum lift amount based on the change history stored in the volatile memory and a predetermined initial value stored in the nonvolatile memory, and sets the actual value and the engine operating state. The maximum lift amount of the engine valve is changed by driving the control shaft so that the deviation from the target value set on the basis of it is reduced.

  By the way, the vibration of the vehicle body or the internal combustion engine may cause a contact failure in the power supply circuit of the microcomputer. In this case, the power supply to the volatile memory may be temporarily stopped, so-called instantaneous interruption. Before and after such a momentary interruption, the state of power supply to the volatile memory is in an unstable state, so that the charge accumulated in the charged memory cell is discharged or discharged due to the inrush current or the like. The memory cell may be charged with electric charge. For this reason, there is a concern that the content of the data stored in the volatile memory changes after power supply is restored from the momentary interruption, and the maximum lift amount cannot be accurately controlled.

  Therefore, in order to minimize the adverse effects due to the instantaneous interruption as described above, the following return processing is executed. That is, the change history data is stored at a predetermined address of the volatile memory during normal control, and the reference data set to have a predetermined correspondence with the history data, such as mirror data, is stored at another address. After the power supply is restored from the momentary interruption, it is determined whether or not the predetermined correspondence relationship is maintained for the remaining data remaining at the two addresses. If it is determined that the predetermined correspondence is maintained, it is determined that the content of the remaining data is the content stored immediately before the instantaneous interruption, and the change history at that time is set to the value indicated in the remaining data. To do. As a result, even when power supply interruption to the volatile memory occurs, control of the maximum lift amount can be resumed promptly after power supply is restored.

On the other hand, if it is determined that the predetermined correspondence relationship is not maintained for the remaining data, it is determined that the content of the data stored in at least one of the addresses has changed due to a momentary interruption, and the normal maximum lift amount is determined. The control is once ended and the reference value learning of the maximum lift amount is executed. Specifically, the actuator is operated to the mechanical limit position of its operating range, and it is determined that the actuator has reached the mechanical limit position on the condition that the change in the operation amount of the actuator stops, The actual value of the maximum lift amount is reset to the reference value of the maximum lift amount corresponding to the limit position stored in the memory.
JP 2005-201117 A

  Thus, by executing the reference value learning of the maximum lift amount, the calculation of the actual value of the maximum lift amount is resumed even when the change history data changes due to the instantaneous interruption of the power supply to the volatile memory. Will be able to. However, the operation of the internal combustion engine may be stopped during the execution of the reference value learning due to, for example, an engine stop operation by the driver. When the operation of the internal combustion engine is stopped in this way, the rotation of the engine output shaft stops, and accordingly, the driving of each member of the engine valve opening / closing device based on the rotational force of the engine output shaft is stopped. Become. Here, when the maximum lift amount of the engine valve is changed during operation of the internal combustion engine, dynamic frictional force is generated in the sliding portion of each member in the opening / closing device. When the maximum lift amount of the valve is changed, the frictional force generated in the sliding portions becomes a static frictional force, so that the resistance force against the operation of the actuator may increase. Further, for example, when the internal combustion engine is stopped in a state where the reaction force of the valve spring acting on the opening / closing device is increased, it is necessary to operate the actuator against the increased reaction force of the valve spring. That resistance will be further increased. Therefore, when the increased resistance force exceeds the driving force of the actuator, it cannot be denied that the actuator stops before reaching its mechanical limit position. When the actuator stops in this way, it is determined that the actuator has reached the mechanical limit position, and the maximum lift amount is erroneously set to a value different from the actual value at that time, that is, a reference value. Become.

  The present invention has been made in view of such a conventional situation, and an object of the present invention is to operate the actuator when the operation of the internal combustion engine is stopped during the execution of the reference value learning for the maximum lift amount of the engine valve. It is an object of the present invention to provide a valve operating system control device capable of avoiding an erroneous setting of the maximum lift amount due to an increase in resistance to the valve.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
According to the first aspect of the present invention, there is provided an opening / closing device for opening / closing an engine valve of the internal combustion engine based on the rotational force of the output shaft of the internal combustion engine, and a machine connected to the opening / closing device via a control shaft provided with a locking portion. And an actuator that changes the maximum lift amount of the engine valve by driving the opening and closing device, history detection means for detecting a change history from a predetermined initial value for the maximum lift amount, and the history detection A volatile memory for storing a change history detected by the means, an actual value calculating means for calculating an actual value of the maximum lift amount based on the change history and the initial value stored in the volatile memory, and After returning from the state where the power supply to the volatile memory is stopped, the remaining data of the change history remaining in the volatile memory is stored immediately before the power supply stop. Determining means for determining whether or not the remaining data of the change history is not data stored immediately before the power supply is stopped by the determining means. the actuator actuates the reference value learning the maximum lift amount of the actual design maximum value of the values the maximum lift amount or design minimum value when operating stops of the actuator but the mechanical limit position abutting against the stopper In a valve-operated control device comprising reference value learning means for executing the reference value learning means, the learning interruption for interrupting the reference value learning when the operation of the internal combustion engine stops during execution of the reference value learning by the reference value learning means The gist is to provide means.

  According to this configuration, when the operation of the internal combustion engine is stopped during the execution of the reference value learning, the reference value learning is interrupted. For this reason, it is mistaken that the actuator has reached the mechanical limit position even though it has stopped before the actuator has reached the mechanical limit position due to an increase in resistance when the actuator is operated. Judgment can be avoided. Accordingly, it is possible to avoid erroneously setting the maximum lift amount of the engine valve to a value different from the actual value based on such erroneous determination.

  Then, as described in claim 2, when the reference value learning is interrupted, the reference value learning is resumed when the internal combustion engine is restarted after that, thereby adopting an internal combustion engine After the engine operation returns from the stopped state, the maximum lift amount can be quickly reset.

  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 cross-sectional view showing a partial cross-sectional structure of an intake / exhaust valve opening / closing device for an internal combustion engine mounted on a vehicle, and FIG. FIG.

  As shown in FIGS. 1 and 2, the internal combustion engine has four cylinders, and a pair of exhaust valves 10 and intake valves 20 corresponding to the cylinders 2 are reciprocally movable in the cylinder head 2 respectively. Is provided. 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 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. 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, a brushless motor 60 is provided at the base end portion (right end portion in the figure) of the control shaft 54, and this brushless motor 60 is connected to the microcomputer 70. ing. The microcomputer 70 controls the brushless motor 60 to perform feedback control so that the maximum lift amount of the intake valve 20 matches the target lift amount according to the engine operating state. Hereinafter, feedback control of the maximum lift amount by the microcomputer 70 will be described with reference to FIGS. Here, FIG. 4 is a block diagram showing the control shaft 54, the brushless motor 60, and the microcomputer 70, and FIG. 6 is a timing chart showing transition states of output waveforms and count values of the sensors.

  As shown in FIG. 4, the base end portion of the control shaft 54 is connected to the output shaft 60 a of the brushless motor 60 via the conversion mechanism 61. The conversion mechanism 61 is for converting the rotational motion of the output shaft 60a into the linear motion of the control shaft 54 in the axial direction. That is, when the output shaft 60a is rotated forward and backward, the rotation is converted into reciprocating movement of the control shaft 54 by the conversion mechanism 61. The control shaft 54 is formed with a locking portion 54a, and the cylinder head cover 3 of the internal combustion engine is formed with two stoppers 3a and 3b with which the locking portion 54a can come into contact. The control shaft 54 can be driven between two drive limit positions where the locking portions 54a come into contact with the stoppers 3a and 3b.

  Here, when the locking portion 54a of the control shaft 54 is driven to the drive limit position where it contacts the stopper 3a, that is, the mechanical upper limit position (hereinafter referred to as “Hi end”) of the operation range, the maximum lift amount is The design maximum value Bhi is obtained. On the other hand, when the locking portion 54a of the control shaft 54 is driven to the drive limit position where it contacts the stopper 3b, that is, the mechanical lower limit position (hereinafter referred to as "Lo end") of the operation range, the maximum lift amount is designed. It becomes the minimum value Blo.

  The brushless motor 60 is provided with three electrical angle sensors D1 to D3 and an 8-pole multipolar magnet (not shown) that rotates integrally with the output shaft 60a in correspondence with the electrical 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 60a 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 60a. 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 60a with respect to the pulse signals from the other electrical angle sensors. It is in the state.

  The brushless motor 60 includes two position sensors S1 and S2 that function as rotary encoders, and a 48-pole multi-pole magnet (not shown) that rotates integrally with the output shaft 60a 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 a 48-pole multipole magnet. The signal “L” is alternately output. Note that the position sensor S1 is arranged at a distance of 176.25 ° from the position sensor S2 in the circumferential direction of the output shaft 60a 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 60a. Further, the pulse signal from the position sensor S2 is in a state in which the phase is shifted to the advance side and the delay side by 3.75 ° rotation of the output shaft 60a with respect to the pulse signal from the position sensor S1.

  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 initial values and the like obtained by learning control. As is well known, when the microcomputer 70 stores data at the address of the DRAM 72b, the bit data of the bit corresponding to each memory cell is obtained by charging / discharging each memory cell corresponding to the address. The value of becomes “1” or “0”. That is, the bit data value of the bit corresponding to the memory cell in which charge is stored is “1”, while the bit data value of the bit corresponding to the memory cell in which charge is not stored is “0”. .

  Further, the microcomputer 70 is connected with a sensor for detecting the operating state of the engine, such as an accelerator sensor 73 for detecting the opening degree of the accelerator pedal of the vehicle and a crank angle sensor 74 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 rotational phase of the brushless motor 60, in other words, 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 60a of the brushless motor 60 rotates as described above. ing. FIGS. 5F to 5H 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 brushless motor 60 rotates. Yes. 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 brushless motor 60. 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 brushless motor 60 based on the electrical angle count value E stored in the DRAM 72b, and switches the energized phase of the brushless motor 60 to rotate the brushless motor 60 forward and backward. Here, during the forward rotation of the brushless motor 60, the electrical angle count value E is forward in the order of “0” → “1” → “2” → “3” → “4” → “5” → “0”. Change. On the other hand, when the brushless motor 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 is the amount of change in the rotation angle of the output shaft 60a with respect to the initial rotation angle at the start of the internal combustion engine, in other words, the maximum lift amount of the intake valve 20 at the start of the engine. Represents the change history from the initial value. 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 brushless motor 60 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. As shown in FIG. 5G, the direction changes in the direction indicated by the arrow A. On the other hand, if the brushless motor 60 is rotating in reverse, the position count value P is subtracted by “1” for each edge of the pulse signal, and the direction indicated by the arrow B along the pattern shown in FIG. It will become to. 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 rotational position of the output shaft 60a of the brushless motor 60 has changed with respect to the initial position when the engine is started. In other words, the maximum lift amount of the intake valve 20 during engine operation is determined by the engine start. This represents how much the initial value 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 is the rotation angle of the brushless motor 60 with the rotation angle of the output shaft 60a when the control shaft 54 is displaced to the Lo end as a reference value (0 degree), in other words, the actual value of the maximum lift amount. Represents. That is, as an initial setting of the stroke count value S, when the control shaft 54 is displaced to the Lo end, 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 the 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 brushless motor 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 reduced. 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, the vibration of the vehicle body or the internal combustion engine may cause a contact failure in the power supply circuit of the microcomputer 70, and a temporary stop of power supply to the DRAM 72b, that is, a so-called instantaneous interruption may occur. Before and after such a momentary interruption occurs, the state of power supply to the DRAM 72b is in an unstable state, so that the charge accumulated in the charged memory cell is discharged or the memory is discharged due to the influence of an inrush current or the like. The cell may be charged. For this reason, there is a concern that the content of data stored in the DRAM 72b changes after power supply is restored from the momentary interruption, and the maximum lift amount cannot be accurately controlled.

  However, in this case, as described above, it is possible to minimize the adverse effects due to such instantaneous interruption by executing the following processing. That is, during normal control, for example, the data of the position count value P is stored at a predetermined address of the DRAM 72b, and the reference data set so as to have a predetermined correspondence with the data is stored at another address. After returning from the disconnection, it is determined whether or not the predetermined correspondence relationship is maintained for the remaining data remaining at the two addresses.

  If it is determined that the predetermined correspondence is maintained, it is determined that the content of the remaining data is the content stored immediately before the instantaneous interruption, and the position count value P at that time is a value indicating the remaining data. Set to. As a result, even when a power interruption to the DRAM 72b occurs, the control of the maximum lift amount can be resumed promptly after the power supply is restored.

  On the other hand, if it is determined that the predetermined correspondence relationship is not maintained for the remaining data, it is determined that the content of the data stored in at least one of the addresses has changed due to an instantaneous interruption. In this case, the actual value of the maximum lift amount can be reset by driving the control shaft 54 to the Hi end and executing the reference value learning of the maximum lift amount. When performing such reference value learning, the maximum driving force of the brushless motor 60 is limited to be smaller than that during normal control so that the load acting on the brushless motor 60 and its peripheral mechanisms does not become excessive.

  As described above, by executing the reference value learning of the maximum lift amount, the calculation of the actual value of the maximum lift amount can be resumed even when the change history data changes due to the instantaneous interruption of the power supply to the DRAM 72b. become able to. However, the operation of the internal combustion engine may be stopped during the execution of the reference value learning due to, for example, an engine stop operation by the driver. When the operation of the internal combustion engine is stopped in this way, the rotation of the engine output shaft stops, and accordingly, the driving of each member of the intake valve opening / closing device 100 based on the rotational force of the engine output shaft is stopped. Become. Here, when the maximum lift amount of the intake valve 20 is changed during operation of the internal combustion engine, the sliding portion of each member (for example, the sliding portion between the output portion 52 and the rocker arm 23 or the like) in the intake valve opening / closing device 100. However, when the maximum lift amount of the intake valve 20 is changed while the internal combustion engine is stopped, the frictional force generated in those sliding portions becomes the static frictional force. Therefore, the resistance force against the operation of the brushless motor 60 may increase.

  Further, for example, when the internal combustion engine is stopped while the reaction force of the valve spring 21 acting on the intake valve opening / closing device 100 is increased, the brushless motor 60 is operated against the increased reaction force of the valve spring 21. Since it needs to be actuated, its resistance is further increased. Therefore, when the increased resistance force exceeds the driving force of the brushless motor 60, it cannot be denied that the control shaft 54 stops before reaching the Hi end. When the control shaft 54 stops in this way, it is determined that the control shaft 54 has reached the Hi end, and the maximum lift amount is erroneously set to a value different from the actual value at that time, that is, the design maximum value Bhi. Will end up. Further, as described above, at the time of learning the reference value, the maximum driving force of the brushless motor 60 is limited, so that the possibility of such an erroneous setting is further increased.

  Therefore, the valve operating control apparatus according to the present embodiment suitably suppresses such inconvenience by adopting the processing described below. Hereinafter, the procedure of processing corresponding to the instantaneous interruption of power supply to the DRAM 72b will be described in detail with reference to the flowcharts of FIGS.

  The 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 interruption flag Fm is “off” (step S10). Here, the learning interruption flag Fm is a flag indicating whether interruption of the reference value learning of the maximum lift amount has occurred, and is set to “ON” or “OFF” in the processing described later.

  If the learning interruption flag Fm is “off” (step S10: YES), it is determined that the reference value learning has not been interrupted, and the current control period is the time after power supply to the DRAM 72b is started. It is determined whether or not it is the first control cycle (step S20). If the current control cycle is not the first control cycle after the start of power supply (step S20: NO), it is determined that power supply has not stopped, and the data of the position count value P is stored in the address ADP1 of the DRAM 72b. At the same time, mirror data obtained by inverting the logic level of the data for each bit is stored as reference data in the address ADP2 of the DRAM 72b (step S21).

  Then, the stroke count value S is calculated based on the position count value P stored in the address ADP1 and the initial value Sg stored in the EEPROM 72c, and the control target value St of the stroke count value S is set based on the engine operating state. . The brushless motor 60 is feedback-controlled so that the difference between the stroke count value S and the control target value St is small (step S22), and this series of processes is temporarily ended.

  On the other hand, when the current control cycle is the first control cycle after the start of power supply (step S20: YES), it is determined that power supply has stopped, and an operation flag Fk indicating the start / stop state of engine operation is determined. Is determined to be “ON” (step S30). Here, the operation flag Fk is set by the CPU 71 based on the operation of the ignition switch of the internal combustion engine and stored in the EEPROM 72c. Specifically, the CPU 71 sets the operation flag Fk to “ON” when the ignition switch of the internal combustion engine is turned on. On the other hand, when the ignition switch is turned off, the operation flag Fk is set to “off” and then the relay is turned off to stop the power supply from the backup power source. Therefore, the operation flag Fk remains set to “ON” in the control cycle immediately after the instantaneous interruption is restored.

  Here, when the operation flag Fk is “OFF” (step S30: NO), it is determined that it is not the return from the momentary interruption but the normal power supply start time, and the feedback control of the normal maximum lift amount ( Steps S21 and S22) are executed to end this series of processes.

  On the other hand, when the operation flag Fk is “ON” (step S30: YES), it is determined that the current control cycle is the control cycle immediately after returning from the momentary interruption, and the remaining data remaining at the addresses ADP1 and ADP2 In step S40, it is determined whether at least one of the exclusive ORs of the bits corresponding to each other is “0”.

  In the remaining data remaining at the addresses ADP1 and ADP2, when the exclusive OR of the bit data corresponding to each other is all “1” (step S40: NO), the remaining data at the addresses ADP1 and ADP2 is immediately before the instantaneous interruption. It is determined that the data is stored in the DRAM 72b in the control cycle, and the position count value P at that time is set to a value indicated by the remaining data of the address ADP1 (step S41). Then, normal feedback control of the maximum lift amount (steps S21 and S22) is resumed, and this series of processes is temporarily ended.

  On the other hand, when at least one of the exclusive OR of the bit data corresponding to each other in the remaining data remaining at the addresses ADP1 and ADP2 is “0” (step S40: YES), the addresses ADP1 and ADP2 It is determined that at least one of the data has been changed by stopping the power supply to the DRAM 72b, and the reference value learning of the maximum lift amount is executed.

  In the reference value learning process, first, the data of the addresses ADP1 and ADP2 are cleared and the position count value P is set to “0” (step S50). Then, it is determined whether or not the rotational speed Ne of the engine output shaft calculated based on the output of the crank angle sensor 74 is higher than the minimum rotational speed Ne0 (for example, 200 rpm) at which the internal combustion engine can be operated independently (step S60). ). If the rotational speed Ne is smaller than the minimum rotational speed Ne0 (step S60: NO), it is determined that the internal combustion engine has stopped, the learning interruption flag Fm is set to “on” (step S61), and the maximum The reference value learning of the lift amount is temporarily interrupted. When the next control cycle is started, since the learning interruption flag Fm is “ON” (step S10: NO), the process proceeds to step S60.

  On the other hand, when the rotational speed Ne is higher than the minimum rotational speed Ne0 (step S60: YES), it is determined that the internal combustion engine is operating, and the position count value P (the value at that time is stored in the DRAM 72b). The stroke count value S is calculated based on the following equation (1) based on the cleared value, that is, “0”, and the initial value Sg stored in the EEPROM 72c (step S70). Further, the control target value St of the stroke count value is calculated through the following equation (2), and the feedback control of the maximum lift amount is executed (step S80).

S ← Sg + P (1)
St ← S + B (2)
B: Increase value

In equation (2), the increase value B is a positive value set in advance. Therefore, the control target value St is set to a value larger than the stroke count value S, and the control shaft 54 is driven so as to be displaced toward the Hi end side. The increase value B is so large that the maximum driving force of the brushless motor 60 is smaller than that during normal control in order to suppress an excessive load acting on the brushless motor 60 and its peripheral mechanisms. Is set as appropriate. As a result, the maximum lift amount increases and the position count value P increases. Then, it is determined whether or not the change amount ΔP of the position count value P is smaller than the threshold value ΔP0 (step S90). When the change amount ΔP is larger than the threshold value ΔP0 (step S90: NO), it is determined that the control shaft 54 is driven, and the process returns to the previous step S60 to continue the reference value learning of the maximum lift amount. To do.

  On the other hand, when the change amount ΔP is smaller than the threshold value ΔP0 (step S90: YES), it is determined that the control shaft 54 has reached the Hi end, and the stroke count value S at that time is set to the Hi end stored in the ROM 72a. The corresponding maximum value Shi is set, in other words, the maximum lift amount at that time is set to the design maximum value Bhi (step S100). Then, the learning interruption flag Fm is set to “off” (step S110), and this series of processing is temporarily ended.

  Hereinafter, with reference to FIG. 9, a specific example of the processing corresponding to the above-described instantaneous power supply interruption will be described. FIG. 9 is a timing chart showing the temporal transition of the rotational speed Ne of the engine output shaft, the actual value of the stroke count value S, and the calculated value thereof.

  When it is determined at time t0 that at least one of the exclusive OR of the bit data of the addresses ADP1 and ADP2 is “0” (step S40: YES), the reference value learning of the maximum lift amount is executed. The First, the data of the addresses ADP1 and ADP2 are cleared and the position count value P is set to “0” (step S50). As shown in FIG. 9, since the rotational speed Ne at time t0 is larger than the minimum rotational speed Ne0 (step S60: YES), the stroke count value S is calculated (step S70), and the stroke count value S is larger than that. A large control target value St is set and feedback control of the maximum lift amount is executed (step S80). As a result, the calculated value of the stroke count value S and the actual value thereof increase. Since the position count value P is set to “0” at time t0, a deviation ΔS occurs between the calculated value of the stroke count value S and its actual value.

  At time t1, when the rotational speed Ne of the output shaft becomes smaller than the minimum rotational speed Ne0 (step S60: NO), it is determined that the operation of the internal combustion engine has stopped, and the learning interruption flag Fm is set to “on” ( Step S61) The reference value learning is temporarily interrupted. Therefore, the stroke count value S and the control target value St are held at a constant value during the period when the operation of the internal combustion engine is stopped.

  When the rotational speed Ne becomes larger than the minimum rotational speed Ne0 at time t2 (step S60: YES), the reference value learning is resumed (steps S70 to S80) so that the stroke count value S and the control target value St increase. Become. At time t3, when the actual value of the stroke count value S reaches its maximum value Shi, that is, when the control shaft 54 reaches the Hi end (step S90: YES), the stroke count value S at that time is stored in the ROM 72a. The maximum value corresponding to the Hi end is set (step S100), and the learning interruption flag Fm is set to “off” (step S110).

According to the embodiment described above, the following effects can be obtained.
(1) When the operation of the internal combustion engine is stopped during the execution of the reference value learning, the reference value learning is interrupted. For this reason, even when the control shaft 54 is driven to the Hi end as in the present embodiment, the control shaft 54 is brought to the Hi end due to an increase in resistance force when the control shaft 54 is driven. It is possible to avoid erroneously determining that the control shaft 54 has reached the Hi end even though it has stopped before reaching. Therefore, it is possible to avoid erroneously setting the maximum lift amount of the intake valve 20 to a value different from the actual value based on such erroneous determination.

  (2) The reference value learning is resumed on condition that the operation of the internal combustion engine returns from the stopped state. As a result, the maximum lift amount can be quickly reset after the operation of the internal combustion engine returns from the stopped state.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, when the content of the position count value P changes due to instantaneous interruption of power supply to the DRAM 72b, the control shaft 54 is driven to the Hi end, and the maximum lift amount is set to the design maximum value Bhi. The case where the present invention is applied to a system control device is illustrated. Not limited to this, the valve operating system drives the control shaft 54 to the Lo end when the content of the data of the position count value P changes due to the instantaneous interruption of the power supply to the DRAM 72b, and sets the maximum lift amount to the design minimum value Bl. Also in this control device, the present invention can be applied in basically the same manner.

  In the above embodiment, when the reference value learning of the maximum lift amount is interrupted, the reference value learning is resumed when the internal combustion engine is restarted. When the reference value learning cannot be resumed immediately after the internal combustion engine is restarted, for example, when the change in the intake air amount is not permitted by other control of the internal combustion engine, for example, a predetermined time has elapsed since the internal combustion engine restarted The reference value learning may be resumed later.

  In the above embodiment, the mirror data is stored in the DRAM 72b as reference data of the position count value P data during normal control. However, the present invention is not limited to this, and for example, a configuration in which data having another correspondence with the data of the position count value P, such as the same data as the data of the position count value P, is stored in the DRAM 72b as reference data.

  In the above embodiment, the DRAM is adopted as the volatile memory for temporarily storing the input data such as the position count value P and the calculation result, but other types of volatile memories such as SRAM are adopted. You can also In the above embodiment, the EEPROM 72c is adopted as the nonvolatile memory for storing the initial value Sg. However, the present invention is not limited to this, and other rewritables such as MRAM (Magnetic RAM) and FeRAM (Ferroelectric RAM) are available. A nonvolatile memory can also be adopted.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the partial cross section structure about the valve operating apparatus of the internal combustion engine concerning one Embodiment of this invention. The top view which shows the arrangement | positioning aspect about the valve operating apparatus 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 block diagram which mainly shows the control shaft of the same embodiment, a brushless motor, 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 the process corresponding to the momentary interruption of the electric power feeding to DRAM by the control apparatus of the embodiment. The flowchart which shows the process sequence about the process corresponding to the momentary interruption of the electric power feeding to DRAM by the control apparatus of the embodiment. 6 is a timing chart for explaining a specific example of processing corresponding to instantaneous interruption of power supply to the DRAM by the control device of the embodiment.

Explanation of symbols

  S1, S2 ... Position sensor, D1-D3 ... Electrical angle sensor, 2 ... Cylinder head, 3 ... Cylinder head cover, 3a, 3b ... Stopper, 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 DESCRIPTION OF SYMBOLS ... Cam, 26 ... Retainer, 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, 54a ... locking portion, 55 ... slider gear, 55a ... helical Prine, 55b ... Helical spline, 55c ... Groove, 56 ... Bush, 56a ... Through hole, 57 ... Locking pin, 60 ... Brushless motor, 60a ... Output shaft, 61 ... Conversion mechanism, 70 ... Microcomputer, 71 ... Central processing Processing unit (CPU), 72a ... nonvolatile memory (ROM), 72b ... volatile memory (DRAM), 72c ... nonvolatile memory (EEPROM), 73 ... accelerator sensor, 74 ... crank angle sensor, 90 ... exhaust valve operating device , 100: Intake valve operating device.

Claims (2)

An opening / closing device that opens and closes an engine valve of the internal combustion engine based on the rotational force of the output shaft of the internal combustion engine, and is mechanically linked to the opening / closing device via a control shaft provided with a locking portion. An actuator for changing the maximum lift amount of the engine valve by driving, a history detecting means for detecting a change history from a predetermined initial value for the maximum lift amount, and a change history detected by the history detecting means are stored. Volatile memory, actual value calculation means for calculating an actual value of the maximum lift amount based on the change history stored in the volatile memory and the initial value, and power supply to the volatile memory are stopped After returning from the state, it is determined whether the remaining data of the change history remaining in the volatile memory is data stored immediately before the power supply is stopped. And a mechanical limit position at which the locking portion of the control shaft comes into contact with the stopper when it is determined by the determining means that the remaining data of the change history is not data stored immediately before the power supply is stopped. the actuator actuates the reference value learning means for executing the reference value learning operation of the actuator is set to the maximum lift amount of the actual design maximum value of the values the maximum lift amount or design minimum value when stopped In a valve system control device comprising:
A valve operating system control device comprising learning interruption means for interrupting the reference value learning when operation of the internal combustion engine is stopped during execution of reference value learning by the reference value learning means. In the valve system control device according to claim 1,
When the reference value learning is interrupted, the reference value learning means restarts the reference value learning when the internal combustion engine is restarted thereafter .

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