JP4175968B2 - Variable valve mechanism control apparatus for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable valve mechanism control apparatus for an internal combustion engine that controls a variable valve mechanism by setting a learning value based on a relationship between a state of the variable valve mechanism and a detection value of a sensor.
[0002]
[Prior art]
An internal combustion engine provided with a variable valve mechanism that makes the valve drive state variable has been proposed. Here, the valve driving state means the valve operating angle, the valve lift amount, and the valve timing of the intake valve and the exhaust valve. Therefore, the variable valve drive state means that the valve operating angle of the intake valve or the exhaust valve, the magnitude of the valve lift, and the advance / retard angle of the valve timing can be changed.
[0003]
Since the control accuracy of such a variable valve mechanism greatly affects the operability of the internal combustion engine, when controlling the drive of the variable valve mechanism, the state of the variable valve mechanism is compared with the detection value of the sensor in advance. Thus, a learning value is obtained, and an accurate state quantity is obtained by correcting the detection value of the sensor based on the learning value. By doing so, an error between the valve drive state by the variable valve mechanism and the detection value of the sensor, which occurs during the manufacture of the internal combustion engine or over time, is compensated to achieve high-precision valve drive control.
[0004]
Specifically, control that moves the opening / closing timing to the most retarded angle side is executed by the variable valve mechanism, and learning is performed from the relationship between the detected value of the sensor at this time and the known state quantity corresponding to the most retarded angle position. The value is calculated | required (for example, refer patent document 1). In this prior art, when the learning value held in the backup RAM or the like is deleted by battery replacement or the like, the learning value is quickly obtained by driving the valve timing to the most retarded state as described above. By obtaining, the deterioration of the drivability of the internal combustion engine due to the absence of the learning value is suppressed as much as possible.
[0005]
[Patent Document 1]
JP 2001-82190 A (page 9-10, FIG. 2)
[0006]
[Problems to be solved by the invention]
However, in the above-described prior art, the variable valve mechanism is forcibly changed to the reference valve drive state (the most retarded state) for obtaining a formal learning value, so that the appropriate valve drive state for the current internal combustion engine When the reference valve driving state is significantly different from the reference valve driving state, the valve driving state becomes more inappropriate. Therefore, the drive for obtaining the official learning value may cause deterioration of the drivability of the internal combustion engine.
[0007]
Further, such a forced change itself may be difficult from the operating state of the internal combustion engine. In this case, the processing of the prior art is impossible, and there is a possibility that the drivability of the internal combustion engine is deteriorated because the state where there is no learning value continues for a very long time.
[0008]
An object of the present invention is to suppress deterioration in drivability of an internal combustion engine until the variable valve mechanism is brought into a reference valve drive state and a formal learning value is obtained.
[0009]
[Means for Solving the Problems]
  In the following, means for achieving the above object and its effects are described.
  The variable valve mechanism control apparatus for an internal combustion engine according to claim 1 is a variable valve mechanism that is driven by an actuator to vary a valve drive state of the internal combustion engine, and detects a state quantity of the valve drive by a sensor. A variable valve mechanism control device for an internal combustion engine that executes control for driving the actuator so that the amount reaches a target value, wherein the variable valve mechanism is set in advance for use in the control. The state quantity detected by the sensor at the time and the known value corresponding to the reference valve drive stateThe valve driveReference valve drive state learning means for setting a learning value for compensating for an error between the actual valve drive state and the state amount detected by the sensor based on a difference from the state amount; and an operation state of the internal combustion engineDifferent from the engine state in which the reference valve is drivenWhen in the reference engine state, the valve drive state of the internal combustion engine is estimated from the reference engine state, and the actual valve drive state is based on the difference between the estimated valve drive state and the state quantity detected by the sensor. And a temporary learning value that compensates for an error between the state quantity detected by the sensor and the temporary learning value is used for the control until the learning value is set by the reference valve driving state learning means. And provisional learning means to be used.
[0010]
  In this way, the temporary learning means sets the temporary learning value until the learning value is formally set by the reference valve driving state learning means. That is, the operating state of the internal combustion engineDifferent from the engine state in which the reference valve is drivenWhen in the reference engine state, the valve driving state of the internal combustion engine is estimated from the reference engine state, and the actual valve driving state is based on the difference between the estimated valve driving state and the state quantity detected by the sensor. And a provisional learning value that compensates for an error between the state quantity detected by the sensor. The temporary learning value is used for controlling the variable valve mechanism until the learning value is officially set.
[0011]
  This temporary learning value is neither an initial value nor a specific value set in advance, and the operating state of the internal combustion engine isDifferent from the engine state in which the reference valve is drivenWhen the engine is in the reference engine state, the operability of the internal combustion engine is set even if the variable valve mechanism is not in the reference valve drive state because it is set based on the valve drive state that is close to reality estimated from the reference engine state. A sufficient value can be set to maintain the value.
  That is, for example, in a specific operating state such as when the internal combustion engine is started or during cold idling, the variable valve mechanism makes it easy to start the internal combustion engine or for stable rotation, so that a specific valve drive state, intake air In the case of a valve, it is arranged at the maximum valve working angle or a valve working angle close thereto. Such a valve drive state is realized mechanically. Therefore, when the internal combustion engine is in the reference engine state, and the internal combustion engine is in the reference engine state, the valve drive state to be detected by the sensor from the reference engine state. Can be estimated. Therefore, the provisional learning value can be obtained based on the difference between the estimated valve driving state to be detected and the actual state amount detected by the sensor.
[0012]
  Thus, the provisional learning value can serve as the learning value, so that it is not necessary to forcibly change to the reference valve drive state, and the control without the learning value does not continue. For this reason, the problem of deterioration of operability of the internal combustion engine caused by the forced change to the reference valve drive state does not occur.That is, for example, it is not necessary to force the reference valve drive state during start-up or cold idling, and since the above-described provisional learning value exists, it is possible to suppress deterioration of startability and rotational stability of the internal combustion engine.
[0013]
Further, even when the forced change to the reference valve driving state itself is difficult from the operating state of the internal combustion engine, the operability of the internal combustion engine is not deteriorated because the temporary learning value described above exists.
[0014]
  Thus, according to the present invention, it is possible to suppress the deterioration of the drivability of the internal combustion engine until the variable valve mechanism is in the reference valve driving state and a formal learning value is obtained.
  According to a second aspect of the present invention, there is provided a variable valve mechanism control apparatus for an internal combustion engine, wherein a variable valve mechanism that is driven by an actuator to vary a valve drive state of the internal combustion engine detects a valve drive state quantity by a sensor, and A variable valve mechanism control device for an internal combustion engine that executes control for driving the actuator so that the amount reaches a target value, wherein the variable valve mechanism is set in advance for use in the control. The state quantity detected by the sensor at the time and the known value corresponding to the reference valve drive stateThe valve driveA reference valve driving state learning means for setting a learning value for compensating an error between an actual valve driving state and a state quantity detected by the sensor based on a difference from the state quantity, and learning by the reference valve driving state learning means valueIs not setIf the operating condition of the internal combustion engine isDifferent from the engine state in which the reference valve is drivenWhen in the reference engine state, the valve drive state of the internal combustion engine is estimated from the reference engine state, and the actual valve drive state is based on the difference between the estimated valve drive state and the state quantity detected by the sensor. And provisional learning means used for the control by setting a provisional learning value that compensates for an error between the state quantity detected by the sensor and the state quantity detected by the sensor.
[0015]
In some cases, it is difficult to use the learning value obtained by the reference valve driving state learning means for control. For example, if the learned value that existed during the previous internal combustion engine operation was backed up due to removal of the battery, etc., but has not yet been learned, to obtain further learned value There may be situations where the reference valve drive state cannot be immediately established even if learning is attempted.
[0016]
  like thisThe learning value by the reference valve drive state learning means is not set inPlaceIfUntil the formal learning value is set, the provisional learning value plays the role of the learning value.
  This temporary learning value is neither an initial value nor a specific value set in advance, and the operating state of the internal combustion engine isDifferent from the engine state in which the reference valve is drivenWhen the engine is in the reference engine state, the operability of the internal combustion engine is set even if the variable valve mechanism is not in the reference valve drive state because it is set based on the valve drive state that is close to reality estimated from the reference engine state. A sufficient value can be set to maintain the value.
  That is, for example, in a specific operating state such as when the internal combustion engine is started or during cold idling, as described above, if the intake valve is a specific valve driving state, the maximum valve operating angle or a valve operating angle close thereto is set. Has been placed. Therefore, when the internal combustion engine is in the reference engine state, and the internal combustion engine is in the reference engine state, the valve drive state to be detected by the sensor from the reference engine state. Can be estimated. Therefore, the provisional learning value can be obtained based on the difference between the estimated valve driving state to be detected and the actual state amount detected by the sensor.
[0017]
  In this way, the provisional learning value can play the role of the learning value, so that it may or may not be forcibly changed to the reference valve driving state, and control in a state where the learning value does not exist is possible. It will not continue. For this reason, the problem of deterioration of operability of the internal combustion engine caused by the forced change to the reference valve drive state does not occur.Yes. That is, for example, it is not necessary to force the reference valve drive state during start-up or cold idling, and since the above-described provisional learning value exists, it is possible to suppress deterioration of startability and rotational stability of the internal combustion engine.
[0018]
  Thus, the present invention can suppress the deterioration of the drivability of the internal combustion engine even if the variable valve mechanism does not obtain a formal learning value in the reference valve driving state.
  The variable valve mechanism control apparatus for an internal combustion engine according to claim 3, wherein the learning value by the reference valve driving state learning means in claim 2.Is not setThe case is characterized in that the learning value memory is lost.
[0019]
  Specifically, the learning value obtained by the reference valve driving state learning means is as follows.Is not setThe case may include a case where the learning value memory is lost. For example, the stored learning value is lost by replacing the battery, replacing the stored memory or the entire board, and the like.
[0020]
In such a case, since the provisional learning value is used, it is possible to suppress the deterioration of the drivability of the internal combustion engine until the variable valve mechanism is brought into the reference valve driving state and the official learning value is obtained.
[0025]
  Thus, the present invention can suppress the deterioration of the drivability of the internal combustion engine during this period even if the official learning value cannot be obtained in the reference valve driving state.
  Claim4In the variable valve mechanism control apparatus for an internal combustion engine according to claim 1,3In any of the above, the valve driving state is a state of a valve operating angle or a valve lift amount.
[0026]
Examples of the valve driving state include a valve working angle or a valve lift state. Since the valve working angle or the valve lift greatly affects the state of the intake air and is largely reflected in the output and emission of the internal combustion engine, it is important that precise control is executed early.
[0027]
According to the present invention, it is possible to precisely adjust the valve working angle or the valve lift amount by setting the provisional learning value even before it is difficult to obtain the formal learning value or when it is difficult to obtain it. The deterioration of the drivability of the internal combustion engine can be suppressed.
[0028]
  Claim5In the variable valve mechanism control apparatus for an internal combustion engine according to claim 1,4The reference valve driving state learning means sets a valve driving state in which a valve operating angle or a valve lift amount is minimized as the reference valve driving state.
[0029]
Examples of the reference valve driving state include a valve driving state in which the valve operating angle or the valve lift amount is minimized. Even if driving by the variable valve mechanism is performed, the valve operating angle or the valve lift is mechanically stopped at the minimum position. Therefore, a learning value is obtained from the relationship between the known state quantity corresponding to this stop state and the sensor detection value. In particular, since a control error on the side where the valve operating angle or valve lift is small greatly affects the operability, it is important to obtain the learning value on the minimum side.
[0030]
As described above, when the official learning value is obtained on the minimum side, it is difficult to set the valve operating angle or the valve lift amount on the minimum side at the time of starting or the like. Even in this case, since the provisional learning value can be set, the valve operating angle or the valve lift amount can be precisely adjusted even if there is no official learning value, and deterioration of the startability of the internal combustion engine can be suppressed.
[0031]
  Claim6In the variable valve mechanism control apparatus for an internal combustion engine according to claim 1,3In any of the above, the valve driving state is valve timing.
[0032]
An example of the valve driving state is valve timing. Since such valve timing greatly affects the state of intake air and is greatly reflected in the output and emission of the internal combustion engine, it is important that precise control is executed at an early stage.
[0033]
According to the present invention, the operability of the internal combustion engine can be adjusted because the valve timing can be precisely adjusted by setting the provisional learning value even before it is difficult to obtain the formal learning value. Can be suppressed.
[0054]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
FIG. 1 shows a schematic configuration diagram of a gasoline engine (hereinafter abbreviated as “engine”) 2 as an internal combustion engine mounted on a vehicle and an electronic control unit (hereinafter referred to as “ECU”) 4 as a control device. ing. The engine 2 is a multi-cylinder engine, here, a 4-cylinder engine, and a variable valve system for one cylinder among them is shown in the longitudinal sectional view of FIG. Each cylinder is provided with two intake valves 2a and two exhaust valves 2b, and is configured as a four-valve engine. The number of cylinders may be 6 cylinders or 8 cylinders, and may be a 2-valve engine or a 5-valve engine.
[0055]
The output of the engine 2 is finally transmitted as traveling driving force to the wheels via the transmission. The engine 2 has a combustion chamber 12 defined by a piston 6, a cylinder block 8 and a cylinder head 10. The cylinder head 10 is provided with a spark plug 14 and a fuel injection valve 16 for directly injecting fuel into the combustion chamber 12 in order to ignite the air-fuel mixture in the combustion chamber 12. The fuel injection valve 16 may inject fuel into the intake port 18 connected to the combustion chamber 12.
[0056]
The intake port 18 is opened and closed by driving the intake valve 2 a, and each intake passage 20 connected to the intake port 18 is connected to a surge tank 22. A throttle valve 26 whose opening degree is adjusted by a motor 24 is provided on the upstream side of the surge tank 22. The throttle valve 26 is normally in a fully open state, but depending on the state of the engine 2, the opening amount (throttle opening TA) may be controlled to adjust the intake air amount GA. The throttle opening degree TA is detected by the throttle opening degree sensor 28 and read into the ECU 4. The intake air amount GA is detected by an intake air amount sensor 30 provided on the upstream side of the throttle valve 26, and the intake air temperature THA is detected by an intake air temperature sensor 32 provided on the upstream side of the throttle valve 26 and is read into the ECU 4. ing.
[0057]
The exhaust port 34 connected to the combustion chamber 12 is opened and closed by driving the exhaust valve 2b. An exhaust purification catalytic converter 38 is disposed in the middle of the exhaust passage 36 connected to the exhaust port 34. An air-fuel ratio AF is detected on the basis of the exhaust component in the exhaust passage 36 by an air-fuel ratio sensor 40 provided in the exhaust passage 36 upstream of the exhaust purification catalytic converter 38 and is read into the ECU 4.
[0058]
The ECU 4 is an engine control circuit configured mainly with a digital computer. In addition to the throttle opening sensor 28, the intake air amount sensor 30, the intake air temperature sensor 32, and the air-fuel ratio sensor 40, the ECU 4 inputs signals from sensors that detect the operating state of the engine 2. That is, an accelerator opening sensor 44 that detects the amount of depression of the accelerator pedal 42 (accelerator opening ACCP), an engine speed sensor 46 that detects the engine speed NE from the rotation of the crankshaft 6a, and a reference crank based on the rotation of the intake camshaft. A signal is input from a reference crank angle sensor 48 that determines the angle. Signals are also input from a rotation angle sensor 50 for detecting a valve operating angle, which will be described later, and a cooling water temperature sensor 52 for detecting an engine cooling water temperature THW. In addition to such sensors, sensors for detecting various data are provided.
[0059]
The ECU 4 controls the fuel injection timing, the fuel injection amount, the throttle opening TA, and the ignition of the engine 2 according to the control signal for the fuel injection valve 16, the throttle valve motor 24 or the ignition plug 14 based on the detection contents from each sensor described above. Control time etc. as appropriate. Further, the ECU 4 controls the valve operating angle and the valve of the intake valve 2a by a control signal for the variable valve mechanism 54 that adjusts the valve operating angle and the valve timing of the intake valve 2a based on the accelerator opening ACCP and the engine speed NE. The timing is adjusted. Of these, the intake air amount is adjusted mainly by the valve operating angle.
[0060]
The variable valve mechanism 54 includes a valve working angle adjustment mechanism 56 and a valve timing adjustment mechanism 58. The valve working angle adjustment mechanism 56 includes a mediation drive mechanism 60 shown in FIGS. 2 to 5 and a shaft slide mechanism 100 shown in FIGS.
[0061]
As shown in FIG. 2, the mediation drive mechanism 60 is disposed between a roller rocker arm 62 provided for the intake valve 2a and an intake cam 64a provided on the intake cam shaft 64, and from the intake cam 64a. The intake valve 2a is driven by applying the valve driving force to the roller rocker arm 62.
[0062]
As shown in the perspective view of FIG. 3 and the horizontal cutaway perspective view of FIG. 4, the intermediate drive mechanism 60 provided for each cylinder is provided at the input portion 66 provided at the center of the drawing and at one end side of the input portion 66. A first rocking cam 68, a second rocking cam 70 provided on the opposite side of the first rocking cam 68, and a slider gear 72 disposed inside are provided.
[0063]
A housing 66a of the input portion 66 forms a space in the axial direction inside, and a helical spline 66b formed in a spiral shape of a right-hand thread is provided in the axial direction on the inner peripheral surface of this space. In addition, two parallel arms 66c and 66d are formed to protrude from the outer peripheral surface of the housing 66a. A roller 66f having a shaft 66e parallel to the axial direction of the housing 66a is rotatably attached to the ends of the arms 66c and 66d. As shown in FIG. 2, the urging force of the spring 66g is applied to the arms 66c and 66d or the housing 66a so that the roller 66f always contacts the intake cam 64a.
[0064]
The housing 68a of the first swing cam 68 forms a space in the axial direction inside, and a helical spline 68b formed in a spiral shape of a left-hand screw in the axial direction is provided on the inner peripheral surface of the internal space. One end of the inner space of the housing 68a is covered with a ring-shaped bearing portion 68c having a center hole with a small diameter. Further, a substantially triangular nose 68d protrudes from the outer peripheral surface of the housing 68a. One side of the nose 68d forms a cam surface 68e that curves in a concave shape.
[0065]
The housing 70a of the second rocking cam 70 forms a space in the axial direction inside, and a helical spline 70b formed in a spiral shape of a left-hand screw in the axial direction is provided on the inner peripheral surface of the internal space. One end of the internal space of the housing 70a is covered with a ring-shaped bearing portion 70c having a center hole with a small diameter. Further, a substantially triangular nose 70d protrudes from the outer peripheral surface of the housing 70a. One side of the nose 70d forms a cam surface 70e that is concavely curved.
[0066]
The first swing cam 68 and the second swing cam 70 are disposed so that the bearing portions 68c and 70c are outside and the end faces are coaxially in contact with the input portion 66 from both sides. As shown in FIG. 3, it has a substantially cylindrical shape having an internal space.
[0067]
A slider gear 72 is disposed in the internal space formed by the input unit 66 and the two swing cams 68 and 70. The slider gear 72 has a substantially cylindrical shape, and an input helical spline 72a formed in a spiral shape of a right-hand thread is provided at the center of the outer peripheral surface. On one end side of the input helical spline 72a, a first output helical spline 72c formed in a left-handed spiral shape with a small diameter portion 72b interposed therebetween is provided. On the opposite side of the first output helical spline 72c, a second output helical spline 72e formed in a left-handed spiral shape with a small diameter portion 72d interposed therebetween is provided. The output helical splines 72c and 72e have a smaller outer diameter than the input helical spline 72a.
[0068]
A through hole 72f is formed in the slider gear 72 in the central axis direction. As shown in the longitudinal section in FIG. 5, a circumferential groove 72g is formed in the circumferential direction on the inner circumferential surface of the through hole 72f at the position of the input helical spline 72a. The circumferential groove 72g is formed with a pin insertion hole 72h penetrating to the outside in a radial direction at one place.
[0069]
A support pipe 80 is slidably disposed in the through hole 72f of the slider gear 72 in the circumferential direction. The support pipe 80 is provided in common with the intermediate drive mechanism 60 for all cylinders. The support pipe 80 has long holes 80a formed in the axial direction at positions corresponding to the respective mediation drive mechanisms 60.
[0070]
Further, a control shaft 82 is disposed in the support pipe 80 so as to be slidable in the axial direction. Support holes 82b in the direction perpendicular to the axis are provided at positions corresponding to the long holes 80a of the support pipe 80. By inserting the base end portion of the control pin 82a into the support hole 82b, the control pin 82a is supported so as to protrude in the direction perpendicular to the axis.
[0071]
In the state where the control shaft 82 is disposed inside the support pipe 80, the tip of each control pin 82 a passes through the axial long hole 80 a formed in the support pipe 80, and the inner periphery of the slider gear 72. It is inserted into a circumferential groove 72g formed on the surface.
[0072]
With such a configuration, each slider gear 72 can move in the axial direction by the movement of the control shaft 82, and the position of the slider gear 72 in each intermediate drive mechanism 60 can be determined by the position control of the control shaft 82. However, since each slider gear 72 is locked to the control pin 82a by the circumferential groove 72g, the slider gear 72 can swing around the axis regardless of the position of the control pin 82a.
[0073]
Within the slider gear 72, the input helical spline 72 a is meshed with the helical spline 66 b inside the input unit 66. The first output helical spline 72 c is meshed with the helical spline 68 b inside the first swing cam 68, and the second output helical spline 72 e is meshed with the helical spline 70 b inside the second swing cam 70.
[0074]
Each intermediary drive mechanism 60 is attached to the cylinder head 10 in a state where movement in the axial direction is prevented on the bearing portions 68c, 70c side of the swing cams 68, 70. Therefore, even if the control shaft 82 moves the slider gear 72 in the axial direction, the input portion 66 and the swing cams 68 and 70 do not move in the axial direction.
[0075]
Therefore, by adjusting the axial movement amount of the slider gear 72 in the internal space of the mediation drive mechanism 60, the input portion 66 and the swing cam 68, by the function of the helical splines 72a, 66b, 72c, 68b, 72e, 70b. The phase difference from 70 can be changed. As a result, the positional relationship between the roller 66f and the noses 68d and 70d can be changed.
[0076]
Here, FIG. 6 shows the operating state of the mediation drive mechanism 60 when the control shaft 82 is moved in the L direction (arrows in FIGS. 3 and 4) as much as possible. 6A is when the valve is closed, and FIG. 6B is when the valve is opened. In this case, the relative positional relationship between the roller 66f of the input unit 66 and the noses 68d and 70d of the swing cams 68 and 70 is the closest. Therefore, as shown in FIG. 6B, even if the intake cam 64a pushes down the roller 66f of the input portion 66 to the maximum extent, the push-down amount of the rocker roller 62a by the cam surfaces 68e and 70e of the noses 68d and 70d is minimized. The valve operating angle and the valve lift amount of the intake valve 2a are minimized. Accordingly, the amount of intake air from the intake port 18 into the combustion chamber 12 is also minimized.
[0077]
FIG. 7 shows the operating state of the mediation drive mechanism 60 when the control shaft 82 is moved in the maximum H direction (arrows in FIGS. 3 and 4). 7A is when the valve is closed, and FIG. 7B is when the valve is opened. In this case, the relative positional relationship between the roller 66f of the input unit 66 and the noses 68d and 70d of the swing cams 68 and 70 is the farthest. Therefore, as shown in FIG. 7B, when the intake cam 64a pushes down the roller 66f of the input portion 66 to the maximum extent, the push-down amount of the rocker roller 62a by the cam surfaces 68e, 70e of the noses 68d, 70d is maximized. The valve operating angle and the valve lift amount of the intake valve 2a are maximized. Accordingly, the intake air amount from the intake port 18 into the combustion chamber 12 is also maximized.
[0078]
By adjusting the axial position of the control shaft 82 in this way, the valve operating angle and the valve lift amount of the intake valve 2a are continuously changed between the state of FIG. 6 and the state of FIG. 7 as shown in FIG. Can be adjusted. In FIG. 8, the state indicated by MIN corresponds to FIG. 6, and the state indicated by MAX corresponds to FIG. As a result, the intake air amount can be adjusted without using the throttle valve 26.
[0079]
A shaft slide mechanism 100 that moves the control shaft 82 in the axial direction is shown in FIG. The shaft slide mechanism 100 includes a drive motor 102 (corresponding to an actuator), a spiral cam mechanism 104, and a rotation angle sensor 50.
[0080]
The drive motor 102 is fixed to the cylinder head 10 and rotates the small-diameter gear 102a by a drive signal from the ECU 4. The small-diameter gear 102a can change the rotational phase of the internal helical cam 108 via the cam shaft 104b rotatably supported by the cylinder head 10 by rotating the large-diameter gear 104a on the helical cam mechanism 104 side. . Further, the cam shaft 104b is provided with a small-diameter gear 104c, and the small-diameter gear 104c rotates the large-diameter gear 106a on the rotation angle sensor 50 side fixed to the cylinder head 10. As a result, the rotation phase of the helical cam 108 is detected by the rotation angle sensor 50 by rotating the rotor inside the rotation angle sensor 50 made of a resolver or the like, and is read into the ECU 4. Note that the stopper arm 104d attached to the cam shaft 104b abuts the two stoppers 104e and 104f that are adjustably fixed to the outside (here, the cylinder head 10), whereby the rotation of the spiral cam 108 is 360 °. It is limited to a smaller range, here 300 °.
[0081]
The configuration of the helical cam mechanism 104 is shown in the perspective view of FIG. The spiral cam mechanism 104 is disposed so as to accommodate the spiral cam 108 in the internal space other than the large-diameter gear 104a, the cam shaft 104b, the small-diameter gear 104c, the stopper arm 104d, the stoppers 104e and 104f, and the spiral cam 108 described above. The cam frame 110 is provided. On this cam frame 110, a roller 110a having a circular cross section that contacts the helical cam surface 108a of the helical cam 108 is rotatably supported by a shaft 110b parallel to the cam shaft 104b. One end of the control shaft 82 described above is fixed to the opposite side of the cam frame 110 from the roller 110a. Therefore, when the cam frame 110 moves in the axial direction of the control shaft 82, the control shaft 82 also changes the axial position in conjunction with it. A spring force is applied to the cam frame 110 or the control shaft 82 in the direction shown in the drawing so that the roller 110a always contacts the helical cam surface 108a of the helical cam 108.
[0082]
Here, the cam frame 110 is moved as follows. As shown in FIG. 11A, by rotating the drive motor 102 (FIG. 9) so that the stopper arm 104d abuts against the minimum working angle side stopper 104e, the spiral cam 108 is most in the spiral cam surface 108a. The side close to the cam shaft 104b contacts the roller 110a. At this time, the cam frame 110 is moved in the L direction as much as possible, and the control shaft 82 is also moved in the L direction as much as possible by the spring force in conjunction with the cam frame 110. Therefore, the state of the minimum valve working angle and the minimum valve lift shown in FIG. 6 is realized.
[0083]
When the driving motor 102 is rotated and the stopper arm 104d is rotated in the R direction as shown in FIG. 11A, the stopper arm 104d is separated from the minimum operating angle side stopper 104e. Accordingly, the roller 110a is moved in the H direction by the helical cam surface 108a of the helical cam 108, and the entire cam frame 110 is also moved in the H direction. In conjunction with this, the control shaft 82 also moves in the H direction against the spring force. Accordingly, the valve working angle and the valve lift amount are increased.
[0084]
Then, as shown in FIG. 11B, when the stopper arm 104d rotates by 300 °, it comes into contact with the maximum operating angle side stopper 104f. As a result, the spiral cam 108 comes into contact with the roller 110a on the side farthest from the cam shaft 104b in the spiral cam surface 108a. At this time, the cam frame 110 moves in the H direction as much as possible, and the control shaft 82 moves in the H direction as much as possible against the spring force in conjunction with the cam frame 110. Therefore, the state of the maximum valve working angle and the maximum valve lift shown in FIG. 7 is realized.
[0085]
As shown in FIG. 12, the helical cam surface 108a of the helical cam 108 has a rotational angle of the helical cam 108 in the range of the width dθx on the maximum valve operating angle (maximum valve lift amount) side (the side farthest from the cam shaft 104b). There is an invariable working angle region in which the distance from the cam shaft 104b does not change even if it changes. Therefore, in the invariable operating angle region, the valve operating angle and the valve lift amount of the intake valve 2a are fixed to the known maximum valve operating angle and the maximum valve lift amount regardless of the rotational phase of the helical cam 108.
[0086]
Therefore, the relationship between the rotation angle θv of the helical cam 108 and the valve operating angle VL is as shown in FIG.
The valve timing adjustment mechanism 58 will be described. The valve timing adjusting mechanism 58 includes an oil control valve (hereinafter referred to as “OCV”) 120 and a vane type hydraulic rotating mechanism 122 as shown in the longitudinal sectional view of FIG. The OCV 120 selectively executes a mode for supplying hydraulic pressure from the oil pump to the advance oil passage, a mode for supplying the retard oil passage, and a mode in which both of the oil passages are hermetically shut off according to a command from the ECU 4. Is.
[0087]
As shown in FIG. 14A, the vane hydraulic rotating mechanism 122 includes a short cylindrical casing 124 formed integrally with the timing sprocket, and a vane body 126 is disposed at the center of the casing 124. . The end portion of the intake camshaft 64 is inserted into the shaft portion 126a at the center of the vane body 126 in an engaged state. As a result, the intake camshaft 64 rotates in conjunction with the vane body 126.
[0088]
Two wall portions 124a and 124b project from the casing 124 to the shaft portion 126a from the axially symmetric position, and are in oil-tight contact with the tip portion. Two vanes 126c and 126d also protrude from the shaft portion 126a of the vane body 126 and are in oil-tight contact with the inner peripheral surface of the casing 124.
[0089]
As a result, the inside of the casing 124 is partitioned into four rooms. Among these, the hydraulic chambers 128 and 130 are connected to the advance oil passage, and the hydraulic chambers 132 and 134 in which the compressed springs 132a and 134a are arranged are connected to the retard oil passage. Stoppers 136 and 138 are provided in the hydraulic chambers 128 and 132 to limit the rotation range of the vane body 126.
[0090]
FIG. 14B shows a state where the hydraulic pressure is discharged from the advance oil passage and the hydraulic pressure is supplied from the retard oil passage. In this case, the hydraulic chambers 132 and 134 are enlarged, the hydraulic chambers 128 and 130 are reduced, and the vane body 126 rotates counterclockwise relative to the casing 124 and comes into contact with the stopper 136. In this state, the valve timing of the intake valve 2a is most retarded.
[0091]
When the hydraulic pressure is not supplied as in the engine 2 stopped state, the vane hydraulic rotating mechanism 122 is in the state shown in FIG. 14B by the springs 132a and 134a.
[0092]
FIG. 14C shows a state in which the hydraulic pressure is discharged from the retarded oil passage and the hydraulic pressure is supplied from the advanced oil passage. In this case, the hydraulic chambers 128 and 130 are expanded, the hydraulic chambers 132 and 134 are contracted, and the vane body 126 rotates clockwise relative to the casing 124 and contacts the stopper 138. In this state, the valve timing of the intake valve 2a is most advanced.
[0093]
14A shows an intermediate state between FIGS. 14B and 14C. In this state, the valve timing of the intake valve 2a is in an intermediate advance state.
Next, the valve working angle control process in which learning is performed based on the relationship between the valve working angle detected by the rotation angle sensor 50 by the ECU 4 and the actual valve working angle will be described.
[0094]
FIG. 15 shows a flowchart of the valve working angle control process. This process is a process that is repeatedly executed at a constant time period.
When this processing is started, first, the load factor (the ratio of the load to the maximum engine load) is determined from a map determined in advance based on experiments based on the operating state of the engine 2, here, the accelerator opening ACCP and the engine speed NE. The target valve operating angle VLt (corresponding to the target value) is set based on this load factor (S102). Based on the detected value (rotation angle θv) of the rotation angle sensor 50, the valve operating angle VL is calculated based on the map shown in FIG. 13 (S104).
[0095]
Next, it is determined whether or not there is an operation state in which the valve operating angle VL is maximized (S106). For example, at the time of starting, in order to obtain the maximum intake air amount, a process of bringing the stopper arm 104d of the spiral cam mechanism 104 into contact with the maximum operating angle side stopper 104f may be performed. Specifically, in step S102, the target valve operating angle VLt is set to a value larger than the maximum valve operating angle set value VLmax. In the state where the stopper arm 104d is in contact with the maximum operating angle side stopper 104f as shown in FIG. 13, the rotation angle θv is included in the width dθx (invariable operating angle region), and the valve operating angle VL is the maximum constant value. However, this maximum constant value is the maximum valve working angle setting value VLmax.
[0096]
When the operation state is such that the valve operating angle VL is maximized (“YES” in S106), it is next determined whether or not the minimum valve operating angle learning value VLg exists (S108). If the minimum valve working angle learning value VLg already exists in the backup RAM of the ECU 4 ("NO" in S108), the maximum valve working angle set value VLmax, which is a known value, is the actual valve working angle VLa. It is set (S114). That is, as described above, when the stopper arm 104d is in contact with the maximum operating angle side stopper 104f, the rotation angle θv is included in the width dθx (invariable operating angle region), and at this time, the valve operating angle is set to the maximum valve operating angle setting. This is because the value VLmax is constant.
[0097]
Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S116). At this time, the motor 102 is driven according to the rotation direction and the rotation angle calculated based on the difference between the actual valve operating angle VLa (= VLmax) and the target valve operating angle VLt (> VLmax). Accordingly, the stopper arm 104d is in contact with the maximum operating angle side stopper 104f. In this way, this process is once completed.
[0098]
Thereafter, as long as the operation state in which the valve operating angle VL is maximized continues, “YES” is determined in Step S106 and “NO” is determined in Step S108. Therefore, the actual valve operating angle VLa is set to the maximum valve operating angle set value VLmax (S114), and the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S116). continue. That is, by bringing the stopper arm 104d into contact with the maximum operating angle side stopper 104f, the state in which the maximum valve operating angle set value VLmax is mechanically maintained continues.
[0099]
When the start is completed and the engine is shifted to the idling state, the target valve operating angle VLt is set smaller than the maximum valve operating angle set value VLmax in step S102 in order to reduce the valve operating angle of the intake valve 2a. Therefore, “NO” is determined in step S106. Therefore, it is next determined whether or not the minimum valve working angle learning value VLg exists (S118). Here, since the minimum valve operating angle learning value VLg already exists in the backup RAM of the ECU 4 (“NO” in S118), the actual valve operating angle VLa is then calculated as shown in Equation 1 (S122). ).
[0100]
[Expression 1]
VLa ← VL−VLg ... [Formula 1]
Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S116), and this process is temporarily terminated.
[0101]
Therefore, if the minimum valve operating angle learning value VLg exists, it is determined as “NO” in step S118 and the valve operating angle VL obtained from the map of FIG. 13 is used as the minimum valve operating angle existing in the backup RAM. The actual valve operating angle VLa is corrected by the learning value VLg and used for drive control of the motor 102.
[0102]
The ECU 4 separately executes a minimum valve working angle learning process shown in FIG. This process is also repeatedly executed at regular time intervals. In this process, the control for minimizing the valve operating angle VL is executed at the time of idling after warm-up, etc., so that the stopper arm 104d is actually set to the minimum operating angle side stopper as shown in FIG. It is determined from the fact that the detected value θv of the rotation angle sensor 50 does not change on the minimum side (S200). As a result of the control, if the stopper arm 104d is in contact with the minimum operating angle side stopper 104e (“YES” in S200), a formal minimum valve operating angle learning value VLg is calculated as shown in Equation 2 (S202).
[0103]
[Expression 2]
VLg ← VL − VLmin ... [Formula 2]
Here, the minimum valve operating angle setting value VLmin is a valve operating angle set in a state where the stopper arm 104d is in contact with the minimum operating angle side stopper 104e when the valve operating angle adjusting mechanism 56 is assembled, and is a known value. .
[0104]
Therefore, if the minimum valve working angle learning value VLg is formally calculated in step S202, the minimum valve working angle learning updated by newly obtained in step S122 of the valve working angle control process (FIG. 15) described above. The actual valve operating angle VLa is calculated using the value VLg.
[0105]
The above-described processing is an example in the case where the minimum valve working angle learning value VLg already exists at the time of starting. Next, the minimum valve working angle is obtained by replacing the battery or the memory clear processing of the backup RAM of the ECU 4. The valve working angle control process (FIG. 15) in a state where the learning value VLg no longer exists will be described.
[0106]
If the valve operating angle VL is maximized at the time of starting ("YES" in S106), the minimum valve operating angle learning value VLg does not exist in this case ("YES" in S108), so that the stopper is surely stopped. It is determined whether or not the arm 104d is in contact with the maximum operating angle side stopper 104f (S109).
[0107]
Whether or not the stopper arm 104d is in contact with the maximum operating angle side stopper 104f is determined based on whether or not the detected value θv of the rotation angle sensor 50 is changed on the maximum side. If the stopper arm 104d is rotating to the maximum side and the stopper arm 104d is not in contact with the maximum operating angle side stopper 104f (“NO” in S109), the steps S114 and S116 are executed, and the motor 102 Drive to the maximum valve working angle side. Thereafter, the above-described processing continues until the stopper arm 104d comes into contact with the maximum operating angle side stopper 104f.
[0108]
When the stopper arm 104d comes into contact with the maximum working angle side stopper 104f (“YES” in S109), a temporary learning value VLp is calculated as shown in Expression 3 (S110).
[0109]
[Equation 3]
VLp ← f (θv−θmax) (Formula 3)
Here, the maximum rotation angle θmax is a known rotation angle output value output by the rotation angle sensor 50 as a standard when the stopper arm 104d is in contact with the maximum operating angle side stopper 104f.
[0110]
f () is a calculation formula or map for converting the difference in rotation angle into the difference in valve operating angle. Here, the value of “θv−θmax” depends on the relationship of the change area where the valve action angle VL increases with the increase of the rotation angle θv, which is an area other than the width dθx (invariable action angle area) shown in FIG. Is converted and set to the provisional learning value VLp. That is, it is calculated as shown in Expression 4 based on the gradient (ΔVL / Δθv) of the change region shown in FIG.
[0111]
[Expression 4]
VLp ← (ΔVL / Δθv) × (θv−θmax) [Equation 4]
Next, the provisional learning value VLp is set to the minimum valve operating angle learning value VLg (S112). And step S114, S116 is performed and this process is once complete | finished.
[0112]
In the next control cycle, even when the valve operating angle VL is in the maximum operating state (“YES” in S106), the minimum valve operating angle learning value VLg exists in the provisional learning (S110, S112) ( ("NO" in S108)), Steps S114 and S116 are executed, and this process is temporarily terminated.
[0113]
When the start is completed and the control shifts to idling control, the target valve operating angle VLt is set smaller than the maximum in step S102 ("NO" in S106). At this time, there is a minimum valve operating angle learning value VLg for which the provisional learning value VLp is set (“NO” in S118). Is calculated (S122).
[0114]
When the engine is completely idle after idling, the control for minimizing the valve operating angle VL is executed by the minimum valve operating angle learning process (FIG. 16) as described above ("YES" in S200). Then, the minimum valve operating angle learning value VLg is formally calculated as shown in the equation 2 (S202). Since the minimum valve working angle learned value VLg is officially calculated in this way, in step S122 of the valve working angle control process (FIG. 15) described above, the actual valve is obtained using the minimum learned valve working angle learned value VLg. The operating angle VLa is calculated, and the drive control of the motor 102 (S116) is performed.
[0115]
In the valve operating angle control process (FIG. 15), when the minimum valve operating angle learning value VLg does not exist and the valve operating angle VL is not maximized or cannot be maximized at the start (in S106). “NO”). In this case, since the minimum valve working angle learning value VLg cannot be set by temporary learning in steps S110 and S112, “YES” is determined in step S118. The actual valve operating angle VLa is set to the value of the valve operating angle VL obtained in step S104 (S120). Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S116).
[0116]
However, at the start in the warm-up state, the formal minimum valve working angle learning value VLg is immediately calculated by the minimum valve working angle learning process (FIG. 16) at the time of warm-up idling (S202). Therefore, the minimum valve operating angle learned value VLg is set early (“NO” in S118 of FIG. 15), and the actual valve operating angle VLa is calculated by being corrected by the minimum valve operating angle learned value VLg as shown in Equation 1 above. (S122).
[0117]
Even when the valve working angle VL is not maximized at the time of start-up, the valve working angle VL may be maximized for rotational stability, particularly during cold idling. Here, it is assumed that the ECU 4 performs control to maximize the valve operating angle VL for rotational stability during cold idling. In this case, if the cold idle state occurs before the official minimum valve operating angle learning value VLg is calculated by the minimum valve operating angle learning process (FIG. 16), the valve operating angle control process (FIG. 15) The operation state is such that the valve operating angle VL is maximized (“YES” in S106).
[0118]
Therefore, when the minimum valve working angle learning value VLg does not exist (“YES” in S108), the stopper arm 104d has come into contact with the maximum working angle side stopper 104f (“YES” in S109), as described above. Steps S110 and S112 are executed, and the minimum valve operating angle learning value VLg is provisionally learned. Therefore, from this time until the official minimum valve operating angle learning value VLg is calculated from the cold idling state to the idle state after warm-up, the actual learning is performed by the temporarily learned minimum valve operating angle learning value VLg. The valve operating angle VLa is calculated (S122), and the motor 102 is driven (S116).
[0119]
Processing examples of the present embodiment are shown in timing charts of FIGS. FIG. 17 shows a case where the engine is started in the warm-up state from time t0 in the state where the minimum valve working angle learning value VLg exists. In the stop process of the engine 2 just before, the stopper arm 104d is in contact with the maximum operating angle side stopper 104f. In this case, after starting (t1), the engine becomes warm-up idle and the valve operating angle VL is changed from the maximum valve operating angle VLmax to the minimum valve operating angle VLmin. Updated.
[0120]
FIG. 18 shows a case where the engine is started in the warm-up state from time t10 in a state where the minimum valve working angle learned value VLg does not exist. Therefore, provisional learning is performed in a state where the valve is driven to the maximum valve operating angle VLmax at the start, and the minimum valve operating angle learned value VLg is temporarily set. Then, after starting (t11), the engine becomes warm-up idle, and after the valve operating angle VL is changed from the maximum valve operating angle VLmax to the minimum valve operating angle VLmin (from t12), the minimum valve operating angle learned value VLg is formally set. Learned and set.
[0121]
FIG. 19 shows an example of an engine in which the valve operating angle VL is smaller than the maximum valve operating angle VLmax during cold start. In this case, a case where the engine is started in the cold state from time t20 in the state where the minimum valve working angle learning value VLg does not exist is shown. Accordingly, after starting (t21 to), when the engine is driven to the maximum valve operating angle VLmax (t22) during cold idling (t21 to t23), provisional learning is performed and the minimum valve operating angle learned value VLg is temporarily set. Then, after the engine is warmed up (from t23) and the valve operating angle VL is changed from the maximum valve operating angle to the minimum valve operating angle (from t24), the minimum valve operating angle learning value VLg is officially learned and set. Is done.
[0122]
In the configuration described above, the ECU 4 corresponds to the variable valve mechanism control device, and the minimum valve operating angle learning process (FIG. 16) corresponds to the process as the reference valve drive state learning means. Therefore, the state in which the stopper arm 104d is in contact with the minimum working angle side stopper 104e is the “reference valve driving state”, and the valve working angle VL converted from the rotational angle θv detected by the rotational angle sensor 50 is the “state quantity”. The minimum valve working angle set value VLmin corresponds to the “known state quantity”.
[0123]
Steps S106 to S112 of the valve working angle control processing (FIG. 15) correspond to processing as temporary learning means. Therefore, the maximum rotation angle θmax corresponds to the “estimated valve drive state”, the rotation angle θv detected by the rotation angle sensor 50 corresponds to the “state amount”, and the start state or the cold idle state corresponds to the “reference engine state”. .
[0124]
According to the first embodiment described above, the following effects can be obtained.
(I). Even if the minimum valve operating angle learned value VLg does not exist, the operation state of the engine 2 (starting or cold) is not calculated until the minimum valve operating angle learned value VLg is calculated in the valve operating angle control process (FIG. 15). The driving state of the intake valve 2a is estimated on the basis of the operating state during idling. Specifically, it is estimated that the spiral cam 108 is at the maximum rotation angle θmax.
[0125]
Based on the relationship between the maximum rotation angle θmax and the rotation angle θv detected by the rotation angle sensor 50 (here, the difference between θmax and θv), a temporary learning value VLp is set (S110), Used to control the valve mechanism 54. Thus, the provisional learning value VLp is used until the minimum valve working angle learning value VLg is officially set in step S202 (FIG. 16). The temporary learning value VLp is neither an initial value nor a specific value set in advance, and is set based on a valve driving state close to reality by the spiral cam 108. Therefore, even if the variable valve mechanism 54 is not set to the minimum valve operating angle, an alternative value of the minimum valve operating angle learned value VLg sufficient to maintain the operability of the engine 2 can be set.
[0126]
As described above, the provisional learning value VLp can play the role of the minimum valve working angle learning value VLg. Therefore, even if the operation state of the engine 2 is not forcibly changed for learning, the learning value does not exist. Control is not continued. For this reason, the problem of the operational stability of the engine 2 caused by the forced driving of the variable valve mechanism 54 does not occur.
[0127]
Further, even in an engine operating state where it is difficult to forcibly drive to the minimum valve operating angle VLmin itself (for example, at the time of starting or during cold idling), the temporary learning value VLp exists, so that the operation stability of the engine 2 is maintained. Will not cause any problems.
[0128]
Accordingly, it is possible to suppress the deterioration of the operability of the engine 2 until the official minimum valve operating angle learning value VLg is calculated by the minimum valve operating angle learning process (FIG. 16).
[0129]
(B). Finally, the official minimum valve operating angle learning value VLg is obtained at the position where the valve operating angle VL is minimum. Particularly in a region where the valve operating angle is small, the control error tends to greatly affect the operability of the engine 2. For this reason, it is important to obtain the learning value on the minimum side of the valve operating angle VL.
[0130]
However, since the official minimum valve operating angle learning value VLg is obtained on the minimum side of the valve operating angle VL in this way, the minimum valve operating angle learned value VLg is set at the time of starting or cold idling. Will be difficult. However, in the present embodiment, as described above, the provisional learning value VLp can be set on the maximum side of the valve operating angle VL. This makes it possible to precisely adjust the valve operating angle at the time of starting or cold idling, so that deterioration of the operability of the engine 2 can be suppressed.
[0131]
[Embodiment 2]
In the present embodiment, the learning target is not the valve working angle but the rotation angle.
The hardware configuration of the present embodiment is the same as that shown in FIGS. 1 to 14 of the first embodiment, and will be described using the same reference numerals. The difference from the first embodiment is that the process shown in FIG. 20 is executed instead of the valve working angle control process (FIG. 15) in the ECU 4. Then, the process of FIG. 21 is executed instead of the minimum valve working angle learning process (FIG. 16).
[0132]
The valve working angle control process (FIG. 20) and the minimum valve working angle learning process (FIG. 21) will be described. These processes are repeatedly executed at a constant cycle.
When the valve working angle control process (FIG. 20) is started, first, the target valve working angle VLt is set as described in step S102 of FIG. 15 (S302).
[0133]
Next, it is determined whether or not the operating state is such that the valve operating angle VL is maximized (S304). Such an operating state is as described in step S106 of FIG. When the operation state is such that the valve working angle VL is maximized (“YES” in S304), it is then determined whether or not there is a minimum valve working angle rotation angle learning value θg set as the rotation angle. (S306). Here, if the learning value θg at the minimum valve operating angle already exists in the backup RAM of the ECU 4 (“NO” in S306), the actual valve operating angle VLa is known by the same processing as step S114 of FIG. A maximum valve working angle set value VLmax is set (S312).
[0134]
Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt by the same processing as step S116 of FIG. 15 (S314), and this processing is once ended.
[0135]
Thereafter, as long as the state where the valve operating angle VL is maximized continues, “YES” is determined in Step S304 and “NO” is determined in Step S306. Therefore, the actual valve working angle VLa is set to the maximum valve working angle set value VLmax (S312), and the motor 102 is driven so that the actual valve working angle VLa becomes the target valve working angle VLt (S314). continue.
[0136]
When the start is completed and the control shifts to idle control, the target valve operating angle VLt is set to be small in step S302 in order to reduce the valve operating angle of the intake valve 2a. Therefore, “NO” is determined in step S304. Next, it is determined whether or not the minimum valve operating angle rotation angle learning value θg exists (S316). Here, since the learning value θg at the minimum valve operating angle already exists in the backup RAM of the ECU 4 (“NO” in S316), the actual rotation angle θa is then calculated as shown in Equation 5. (S320).
[0137]
[Equation 5]
θa ← θv − θg ... [Formula 5]
Next, the actual valve operating angle VLa is calculated from the actual rotation angle θa using the map shown in FIG. 13 (S322). Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S314), and this process is temporarily terminated.
[0138]
Therefore, if the minimum valve working angle rotation angle learning value θg exists, it is determined as “NO” in step S316, and the rotation angle sensor 50 actually uses the minimum valve working angle rotation angle learning value θg. The actual rotation angle θa is obtained by correcting the detected rotation angle θv. Based on the actual rotation angle θa, the actual valve operating angle VLa is obtained and used for driving control of the motor 102.
[0139]
The ECU 4 separately executes the minimum valve working angle learning process of FIG. In this process, when idling after warm-up, etc., control is performed to minimize the valve operating angle VL that causes the stopper arm 104d to contact the minimum operating angle side stopper 104e (“YES” in S402). The rotational angle learning value θg at the minimum valve operating angle is formally calculated as in Expression 6 (S404).
[0140]
[Formula 6]
θg ← θv − θmin ... [Formula 6]
Here, the minimum valve operating angle rotation angle setting value θmin is a rotation angle detection value output by the standard rotation sensor 50 in a state where the stopper arm 104d is in contact with the minimum operating angle side stopper 104e, and is a known value. .
[0141]
Therefore, if the minimum valve working angle rotation angle learning value θg is formally calculated in step S404, the minimum valve working angle newly obtained and updated in step S320 of the valve working angle control process (FIG. 20) described above. The actual rotation angle θa is calculated using the hourly rotation angle learning value θg.
[0142]
The above-described processing is an example in the case where the learning value θg at the minimum valve operating angle already exists. Next, the minimum valve operating is performed by replacing the battery or the memory clear processing of the backup RAM of the ECU 4. The valve working angle control process (FIG. 20) when the angular rotation angle learning value θg no longer exists will be described.
[0143]
In the operation state in which the valve operating angle VL is maximized at the time of starting (“YES” in S304), the rotation angle learning value θg at the minimum valve operating angle does not exist here (“YES” in S306). Whether the stopper arm 104d is in contact with the maximum operating angle side stopper 104f is determined (S307).
[0144]
The determination in step S307 is as described in step S109 in FIG. If the stopper arm 104d is not in contact with the maximum operating angle side stopper 104f (“NO” in S307), the above steps S312 and S314 are executed to drive the motor 102 to the maximum valve operating angle side. Thereafter, the above-described processing continues until the stopper arm 104d comes into contact with the maximum operating angle side stopper 104f.
[0145]
When the stopper arm 104d comes into contact with the maximum working angle side stopper 104f (“YES” in S307), a temporary learning value θp is calculated as shown in Expression 7 (S308).
[0146]
[Expression 7]
θp ← θv − θmax ... [Formula 7]
Here, the maximum rotation angle θmax is as described in step S110 of FIG.
[0147]
Next, the provisional learning value θp is set to the minimum valve operating angle rotation angle learning value θg (S310). And step S312 and S314 are performed and this process is once complete | finished. In the next control cycle, even when the valve operating angle VL is in the maximum operating state (“YES” in S304), the minimum valve operating angle rotation angle learning value θg exists in provisional learning (S308, S310). Therefore (“NO” in S306), Steps S312 and S314 are executed, and this process is temporarily terminated.
[0148]
When the start is completed and the control shifts to idle control, the target valve operating angle VLt is set smaller than the maximum in step S302 (“NO” in S304). At this time, there is a minimum valve working angle rotation angle learning value θg for which the provisional learning value θp is set (“NO” in S316). Using this, the actual rotation angle θa is calculated (S320).
[0149]
When the engine is completely idle after being warmed up, the control for minimizing the valve operating angle VL is executed by the minimum valve operating angle learning process (FIG. 21) as described above ("YES" in S402). Then, the rotational angle learning value θg at the minimum valve operating angle is officially calculated as in the above equation 6 (S404). Since the minimum valve working angle rotation angle learned value θg is formally calculated in this way, the formal minimum valve working angle rotation angle learned value θg is used in step S320 of the above-described valve working angle control process (FIG. 20). Thus, the actual rotation angle θa is calculated.
[0150]
In the valve operating angle control process (FIG. 20), when the valve operating angle VL is not maximized or cannot be maximized at the start in the state where the learning value θg at the minimum valve operating angle does not exist. (“NO” in S304) is considered. In this case, since the minimum valve working angle rotation angle learning value θg is not set in the provisional learning in steps S308 and S310, “YES” is determined in step S316. The actual rotation angle θa is set to the value of the rotation angle θv detected by the rotation angle sensor 50 (S318). Then, the actual valve operating angle VLa is calculated from the actual rotation angle θa (S322), and the motor 102 is driven so as to become the target valve operating angle VLt (S314).
[0151]
However, immediately after starting in the warm-up state, a formal minimum valve working angle rotation angle learning value θg is immediately calculated by the minimum valve working angle learning process (FIG. 21) in the warm-up idle state (S404). Therefore, the minimum valve working angle rotation angle learning value θg is set at an early stage (“NO” in S316), and the actual rotation angle θa is corrected by the minimum valve working angle rotation angle learning value θg as shown in Equation 5 above. It is calculated (S320).
[0152]
Here, it is assumed that the ECU 4 performs control to maximize the valve operating angle VL for rotational stability during cold idling. In this case, if the cold idle state occurs before the official minimum valve working angle rotation angle learning value θg is calculated by the minimum valve working angle learning process (FIG. 21), the valve working angle control process (FIG. In 20), the valve operating angle VL is maximized ("YES" in S304).
[0153]
Therefore, when the rotation angle learning value θg at the minimum valve working angle does not exist (“YES” in S306), if the stopper arm 104d surely contacts the maximum working angle side stopper 104f (“YES” in S307), Steps S308 and S310 are executed. As a result, the provisional learning value θp is set as the minimum valve operating angle rotation angle learning value θg. Therefore, during the period from the subsequent cold idle state to the idle state after warm-up until the official minimum valve operating angle rotation angle learning value θg is calculated, the provisionally learned minimum valve operating angle rotation angle is calculated. The actual rotation angle θa is calculated from the learning value θg (S320). Then, the actual valve operating angle VLa is calculated from the actual rotation angle θa (S322), and the motor 102 is driven to reach the target valve operating angle VLt (S314).
[0154]
Processing examples of the present embodiment are shown in the timing charts of FIGS. 22 corresponds to the case of FIG. 17 of the first embodiment, FIG. 23 corresponds to the case of FIG. 18, and FIG. 24 corresponds to the case of FIG. As illustrated, the minimum valve working angle rotation angle learned value θg is set in the same manner as the minimum valve working angle learned value VLg of the first embodiment.
[0155]
In the configuration described above, the minimum valve working angle learning process (FIG. 21) corresponds to the process as the reference valve driving state learning means. Therefore, the state in which the stopper arm 104d is in contact with the minimum operating angle side stopper 104e is the “reference valve driving state”, the rotational angle θv detected by the rotational angle sensor 50 is the “state amount”, and the rotational angle at the minimum valve operating angle. The set value θmin corresponds to the “known state quantity”.
[0156]
Steps S304 to S310 of the valve working angle control processing (FIG. 20) correspond to processing as temporary learning means. Therefore, the maximum rotation angle θmax corresponds to the “estimated valve drive state”, the rotation angle θv detected by the rotation angle sensor 50 corresponds to the “state amount”, and the start state or the cold idle state corresponds to the “reference engine state”. .
[0157]
According to the second embodiment described above, the following effects can be obtained.
(I). The same effects as (a) and (b) of the first embodiment can be obtained.
[Embodiment 3]
In this embodiment, as shown in FIG. 25, the shaft slide mechanism 300 detects the slide amount SLv of the control shaft 82 interlocked with the cam frame 110 by the slide sensor 350 without providing the rotation angle sensor.
[0158]
Here, the slide sensor 350 is a differential transformer type displacement sensor, and includes a rod-shaped core 350a provided on the cam frame 110 side and a coil 350b provided on the cylinder head 10 (FIG. 2) side. When the helical cam 108 is rotated by the motor 102 and the cam frame 110 moves the control shaft 82 in the axial direction, the rod-shaped core 350a moves relative to the coil 350b. Thus, the slide amount SLv of the control shaft 82 can be detected.
[0159]
The other hardware configuration is the same as that of the first embodiment. The same components will be described with the same reference numerals.
In terms of control, the processing shown in FIG. 26 is executed instead of the valve operating angle control processing (FIG. 15) in the ECU 4. The minimum valve working angle learning process (FIG. 16) is the same as in the first embodiment. Thus, in this embodiment, the valve operating angle VL is learned.
[0160]
The valve working angle control process (FIG. 26) will be described. This process is repeatedly executed at a constant cycle. When the valve working angle control process (FIG. 26) is started, first, the target valve working angle VLt is set by the same process as step S102 of FIG. 15 (S502). Then, the valve operating angle VL is calculated from the detection value SLv of the slide sensor 350 (S504). As shown in FIG. 27, this calculation is performed based on a map representing the relationship between the slide amount SL measured by a standard slide sensor in advance through experiments and the valve operating angle VL of the intake valve 2a.
[0161]
Next, it is determined whether or not the minimum valve working angle learning value VLg exists (S506). If the minimum valve operating angle learned value VLg already exists in the backup RAM of the ECU 4 (“NO” in S506), the actual valve operating angle VLa is then calculated as shown in Equation 8 (S516).
[0162]
[Equation 8]
VLa ← VL−VLg ... [Formula 8]
Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt by the same control processing as in step S116 of FIG. 15 (S520), and this processing is temporarily ended.
[0163]
Therefore, if the minimum valve operating angle learned value VLg exists, it is determined as “NO” in step S506 and the valve operating angle VL obtained from the map of FIG. 27 is determined as the minimum valve operating angle learned value VLg existing in the backup RAM. Is corrected to the actual valve operating angle VLa and used for drive control of the motor 102.
[0164]
As described in the first embodiment, the ECU 4 separately executes the minimum valve working angle learning process shown in FIG. Therefore, if the minimum valve working angle learned value VLg is formally calculated in step S202 (FIG. 16), the minimum valve working angle learned value newly obtained in step S516 of the valve working angle control process (FIG. 26) described above. The actual valve operating angle VLa is calculated using VLg.
[0165]
The above-described processing is an example in the case where the minimum valve working angle learned value VLg already exists. Next, the minimum valve working angle learned value is obtained by replacement of the battery or the memory clear processing of the backup RAM of the ECU 4. The valve working angle control process (FIG. 26) in the case where VLg does not exist will be described.
[0166]
Since the minimum valve operating angle learned value VLg does not exist after the processing of steps S502 and S504 (“YES” in S506), it is next determined whether or not the operating state is driving the valve operating angle VL to the maximum (S508). ). Since the valve operating angle VL is maximized at the time of starting (“YES” in S508), the slide sensor 350 is set regardless of the rotation of the helical cam 108 toward the maximum valve operating angle by the motor 102. It is determined whether or not the detected value SLv has changed (S510).
[0167]
As shown in FIGS. 12 and 13 of the first embodiment, the helical cam surface 108a of the helical cam 108 has a cam shaft even if the rotational angle of the helical cam 108 changes within the range of the width dθx on the maximum valve operating angle side. There is an invariable working angle region where the distance to 104b does not change. Therefore, when the roller 110a is in contact with the invariable working angle region, the detected value SLv of the slide sensor 350 is not changed regardless of the rotational phase of the spiral cam 108, and the valve working angle and the valve lift amount of the intake valve 2a are known. The maximum valve working angle and the maximum valve lift amount are fixed. Therefore, step S510 is for determining whether or not this invariable working angle region has been reached.
[0168]
While the detected value SLv of the slide sensor 350 is changed when the motor 102 is driven to the maximum valve operating angle side (“NO” in S510), the maximum valve operating angle set value VLmax is set to the actual valve operating angle VLa ( S518). Then, drive control of the motor 102 is performed so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S520).
[0169]
When the roller 110a comes into contact with the invariable operating angle region due to the rotation of the helical cam 108, the detection value SLv of the slide sensor 350 is not changed regardless of the driving of the motor 102 to the maximum valve operating angle side (in S510, “ YES "), and next, provisional learning value VLp is set as shown in Equation 9 (S512).
[0170]
[Equation 9]
VLp ← VL−VLmax (Equation 9)
Here, the maximum valve operating angle VLmax is a known valve operating angle in the width dθx (invariable operating angle region) existing in the helical cam 108 as described with reference to FIG. 12 of the first embodiment, and is constant within the width dθx. It is. Even if the valve operating angle VL is increased to the maximum by rotating the motor 102, the valve operating angle VL stops at the maximum valve operating angle VLmax by such a mechanical setting. Therefore, the difference between the valve operating angle VL calculated on the maximum valve operating angle side and the maximum valve operating angle VLmax based on the detection value SLv of the slide sensor 350 can be set as the provisional learning value VLp.
[0171]
Then, the provisional learning value VLp is set to the minimum valve operating angle learning value VLg (S514), the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S520), and this process is performed once. Exit.
[0172]
In the next control cycle, the minimum valve working angle learning value VLg exists in the provisional learning (S512, S514) (“NO” in S506), so steps S516 and S520 are executed, and this process is temporarily terminated.
[0173]
Thereafter, after the valve operating angle is controlled by the minimum valve operating angle learned value VLg to which the provisional learning value VLp is set, if the engine is in an idle state after warming up, the control that minimizes the valve operating angle VL as described above. Is executed. As a result, the minimum valve working angle learning value VLg is formally calculated by the minimum valve working angle learning process (FIG. 16) (S202). Since the minimum valve working angle learned value VLg is formally calculated in this way, in step S516 of the valve working angle control process (FIG. 26) described above, the actual valve working angle VLa is used by using the formal minimum valve working angle learned value VLg. Is calculated.
[0174]
In the valve working angle control process (FIG. 26), when the minimum valve working angle learning value VLg does not exist (“YES” in S506), the valve working angle VL is not maximized at the start or is maximized. Consider a case where it was not possible (“NO” in S508). In this case, the valve operating angle VL obtained in step S504 is set as the actual valve operating angle VLa (S509), and the motor 102 is driven (S520).
[0175]
However, at the start in the warm-up state, the formal minimum valve working angle learning value VLg is immediately calculated by the minimum valve working angle learning process (FIG. 16) at the time of warm-up idling (S202). Therefore, the minimum valve operating angle learned value VLg is set at an early stage, and the actual valve operating angle VLa corrected by the minimum valve operating angle learned value VLg is calculated as in Equation 8 (S516).
[0176]
Here, it is assumed that the ECU 4 performs control to maximize the valve operating angle VL for rotational stability during cold idling. In this case, if the cold idle state occurs before the official minimum valve working angle learning value VLg is calculated by the minimum valve working angle learning process (FIG. 16), the valve working angle control process (FIG. 26) The operation state is such that the valve operating angle VL is maximized (“YES” in S508).
[0177]
Therefore, after the detection value SLv of the slide sensor 350 is not changed (“YES” in S510), the aforementioned steps S512 and S514 are executed, and the minimum valve operating angle learning value VLg is provisionally learned. Therefore, during the period from the subsequent cold idle state to the idle state after warm-up until the official minimum valve operating angle learned value VLg is calculated, the actual valve is calculated based on the temporarily learned minimum valve operating angle learned value VLg. The operating angle VLa is calculated (S516) and controlled to the target valve operating angle VLt (S520).
[0178]
With such a configuration, processing as shown in the timing chart of the first embodiment (FIGS. 17 to 19) is performed.
In the configuration described above, the minimum valve working angle learning process (FIG. 16) corresponds to the process as the reference valve drive state learning means. Therefore, the state in which the stopper arm 104d is in contact with the minimum operating angle side stopper 104e is the “reference valve driving state”, and the valve operating angle VL converted from the slide amount SLv detected by the slide sensor 350 is the minimum “state amount”. The valve operating angle set value VLmin corresponds to the “known state quantity”.
[0179]
Steps S506 to S514 of the valve working angle control processing (FIG. 26) correspond to processing as temporary learning means. Accordingly, the maximum valve operating angle VLmax corresponds to the “estimated valve driving state”, the valve operating angle VL detected by the slide sensor 350 corresponds to the “state amount”, and the start state or the cold idle state corresponds to the “reference engine state”. To do.
[0180]
According to the third embodiment described above, the following effects can be obtained.
(I). The same effects as (a) and (b) of the first embodiment can be obtained.
(B). If there is no change in the slide amount SLv (“YES” in S510), since provisional learning is performed, the frequency of completion of provisional learning increases before the stopper arm 104d comes into contact with the maximum working angle side stopper 104f. For this reason, even if the determination in step S508 becomes “NO” in a short time for some reason, the probability that the minimum valve working angle learning value VLg by temporary learning is set is increased, and suppression of deterioration of the drivability of the engine 2 is suppressed. It can be more effective.
[0181]
[Embodiment 4]
This embodiment shows a control example in which provisional learning is executed with the valve operating angle maximized within a range that does not affect engine operation.
[0182]
The hardware configuration of the present embodiment is the same as that shown in FIGS. 1 to 14 of the first embodiment, and will be described using the same reference numerals. The difference from the first embodiment is that the processing shown in FIGS. 28 and 29 is executed instead of the valve working angle control processing (FIG. 15) in the ECU 4. The minimum valve working angle learning process (FIG. 16) is the same.
[0183]
The valve working angle control process (FIGS. 28 and 29) will be described. These processes are repeatedly executed at a constant cycle. When this process starts, first, the target valve operating angle VLt is calculated and set as described in step S102 of FIG. 15 (S602). Then, as described in step S104 of FIG. 15, the valve operating angle VL is calculated based on the detected value (rotation angle θv) of the rotation angle sensor 50 based on the map shown in FIG. 13 (S604).
[0184]
Next, it is determined whether or not the minimum valve operating angle learning value VLg exists (S606). If the minimum valve operating angle learned value VLg already exists in the backup RAM of the ECU 4 (“NO” in S606), the actual valve operating angle VLa is calculated as shown in Equation 10 (S620).
[0185]
[Expression 10]
VLa ← VL−VLg ... [Formula 10]
Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S622), and this process is temporarily terminated.
[0186]
Thereafter, the above-described processing is repeated. During this time, when step S202 is executed by the minimum valve operation angle learning process (FIG. 16) and the minimum valve operation angle learning value VLg is updated, a new minimum valve operation is performed in step S620. The actual valve operating angle VLa is calculated from the learned angle value VLg.
[0187]
On the other hand, when the minimum valve working angle learning value VLg does not exist (“YES” in S606), it is then determined whether or not the engine 2 is in an operating state in which drive control with the valve working angle VL as the maximum valve working angle is possible. Determined.
[0188]
The driving state in which the drive control with the valve operating angle VL as the maximum valve operating angle includes a state in which the valve operating angle VL has already been maximized. In addition to this, the target valve operating angle VLt is close to the maximum. Thus, it includes a state that can be performed without causing problems in engine operation by executing cooperative control with the throttle opening control side. In other words, even if the current valve operating angle is changed to the maximum valve operating angle, the throttle valve 26 is throttled on the throttle opening control side so that the operating state can be driven with almost no influence on the intake air amount. Such an operating state is obtained and mapped in advance for each state of the valve operating angle VL, the engine speed NE, and the intake air amount GA through experiments. In step S608, based on the presence / absence of application of this map, and further application, driving that maximizes the valve operating angle VL from the values of the valve operating angle VL, the engine speed NE, and the intake air amount GA. It is determined whether or not the operation state is controllable. For example, the map may not be applied at the start, and the map may be applied at other times than the start. Or you may make it apply a map by all the driving | running states.
[0189]
Here, if the map is applied to an operation state in which the drive control can be performed with the valve operating angle VL as the maximum valve operating angle (“YES” in S608), it is determined whether or not the maximum valve operating angle has already been reached. (S610). If it is not yet the maximum valve operating angle (“NO” in S610), as described above, the intake valve 2a is driven by the motor 102 in conjunction with the drive in the closing direction of the throttle valve 26 by the cooperative control with the throttle opening control side. Is maximized (S618). Whether or not the valve operating angle is maximized is determined by stopping the increase in the detected value θv of the rotation angle sensor 50 by the stopper arm 104d coming into contact with the maximum operating angle side stopper 104f.
[0190]
If the valve operating angle is maximized (“YES” in S610), a temporary learning value VLp is then calculated as shown in Expression 11 (S612).
[0191]
[Expression 11]
VLp ← f (θv−θmax) (Equation 11)
The maximum rotation angle θmax, f () is as described in step S110 (FIG. 15) of the first embodiment.
[0192]
Next, the provisional learning value VLp is set to the minimum valve operating angle learning value VLg (S614), and the maximum valve operating angle setting value VLmax is set to the actual valve operating angle VLa (S616).
[0193]
Then, the throttle opening control side is requested to return so that the throttle valve 26 returns to the original state (S617), and this process is temporarily terminated. In response to this request, the throttle opening control side gradually returns the throttle valve 26 to the original throttle opening state.
[0194]
In the next control cycle of the valve operating angle control process (FIGS. 28 and 29), the target valve operating angle VLt is calculated in conformity with the return amount of the throttle opening TA (S602), and the detected value θv of the rotation angle sensor 50 is calculated. From the above, the valve operating angle VL is calculated (S604). As the minimum valve operating angle learning value VLg, the provisional learning value VLp is set in the process of the previous step S614 (“NO” in S606). For this reason, the actual valve operating angle VLa is calculated as in Equation 10 (S620), the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S622), and this process is temporarily terminated. .
[0195]
The valve operating angle of the intake valve 2a is controlled by the minimum valve operating angle learned value VLg provisionally learned in this way. Then, when the engine is warm-up idle, step S202 is executed by the minimum valve operating angle learning process (FIG. 16) to formally set the minimum valve operating angle learned value VLg, and the official minimum valve operating angle learned value VLg is used. The valve working angle control is performed.
[0196]
The case where the driving state in which the drive control for maximizing the valve operating angle VL is not possible in step S608 (“NO” in S608) will be described. In this case, the value of the valve operating angle VL obtained in step S604 is set to the actual valve operating angle VLa (S624). Then, the motor 102 is driven so that the actual valve operating angle VLa becomes the target valve operating angle VLt (S622). However, at the start in the warm-up state, the formal minimum valve working angle learning value VLg is immediately calculated by the minimum valve working angle learning process (FIG. 16) in the warm-up idle state. Therefore, the minimum valve operating angle learned value VLg is set early (“NO” in S606), and the actual valve operating angle VLa is corrected and calculated by the minimum valve operating angle learned value VLg as shown in Equation 10 above. (S620).
[0197]
During cold idling, the valve operating angle VL is maximized for rotational stability. Therefore, in this case, when the minimum valve working angle learned value VLg does not exist (“YES” in S606), “YES” is set in Step S608, and the minimum valve working angle learned value is set as described above. VLg is provisionally learned. For this reason, in the period until the official minimum valve operating angle learned value VLg is calculated from the cold idle state after the warm-up to the idle state after the warm-up, the provisionally learned minimum valve operating angle learned value VLg is used. The actual valve operating angle VLa is calculated (S620) and controlled to the target valve operating angle VLt (S622).
[0198]
Processing examples of the present embodiment are shown in the timing charts of FIGS. FIG. 30 shows a case where the engine is started in the warm-up state from time t40 in a state where the minimum valve working angle learning value VLg exists. In this engine, the valve operating angle is slightly smaller than the maximum valve operating angle set value VLmax at the start. After starting (t41), the engine is warmed up and the valve operating angle VL is changed to the minimum valve operating angle VLmin (t42-), and the minimum valve operating angle learned value VLg is updated.
[0199]
FIG. 31 shows a case where the engine is started in the warm-up state from time t50 in a state where the minimum valve working angle learned value VLg does not exist. Since this engine must have a valve operating angle smaller than the maximum valve operating angle VLmax at the time of starting, provisional learning is not performed at the time of starting. However, since the engine is started in the warm-up state, after the engine is started (t51), the engine is warmed-up idle and the valve operating angle VL is changed to the minimum valve operating angle (t52-). The learning value VLg is learned and set.
[0200]
FIG. 32 shows an example in which the valve operating angle is made smaller than the maximum valve operating angle VLmax during cold idling. However, the engine can be set to the maximum valve operating angle VLmax by cooperative control with the throttle opening control side during cold idling. When starting in the cold state from time t60 in the state where the minimum valve working angle learning value VLg does not exist, after the start (t61 to), during cold idling (t61 to t64), the maximum temporarily It is driven to the valve operating angle VLmax (t62 to t63). Thus, provisional learning is performed at the maximum valve operating angle VLmax, and the minimum valve operating angle learned value VLg is set (t63). Then, after the engine becomes warm-up idle (t64-) and the valve operating angle VL is changed to the minimum valve operating angle (t65-), the minimum valve operating angle learning value VLg is formally learned and set.
[0201]
In the configuration described above, the minimum valve working angle learning process (FIG. 16) corresponds to the process as the reference valve drive state learning means. Therefore, the state in which the stopper arm 104d is in contact with the minimum working angle side stopper 104e is the “reference valve driving state”, and the valve working angle VL converted from the rotational angle θv detected by the rotational angle sensor 50 is the “state quantity”. The minimum valve working angle set value VLmin corresponds to the “known state quantity”.
[0202]
Steps S606 to S614 of the valve working angle control processing (FIGS. 28 and 29) correspond to processing as temporary learning means. Therefore, the rotation angle θv detected by the rotation angle sensor 50 is “state quantity”, the state when the valve operating angle of the intake valve 2a is maximized is “temporary reference valve driving state”, and the maximum rotation angle θmax is “temporary”. This corresponds to “a known state quantity corresponding to the reference valve driving state”.
[0203]
According to the fourth embodiment described above, the following effects can be obtained.
(I). The same effects as (a) and (b) of the first embodiment can be obtained.
(B). Even if the valve operating angle is not the maximum, if the operating condition allows the valve operating angle to be maximized, the minimum valve operating angle learning value can be obtained by tentative learning by actively maximizing the valve operating angle. Since VLg is set, the chances of setting a provisional learning value can be increased.
[0204]
Thus, it is difficult to obtain the formal minimum valve working angle learned value VLg because the minimum valve working angle learned value VLg does not exist and the transition to the minimum valve working angle state cannot be performed or the transition takes time. Even in this case, the provisional learning value can be obtained by positively shifting to the maximum valve operating angle. For this reason, the frequency with which the control in the state where the minimum valve working angle learning value VLg does not exist at all is continued for a long time decreases.
[0205]
In this way, it is possible to suppress the deterioration of the operability of the engine until the formal minimum valve working angle learning value VLg is obtained.
[Other embodiments]
(A). In each of the above-described embodiments, the mediation drive mechanism is a type in which the valve operating angle and the valve lift amount are adjusted by the axial movement of the control shaft, but as shown in FIGS. 33 and 34 without the mediation drive mechanism. By configuring, the valve working angle and the valve lift amount may be adjusted. That is, the intake cam 464a may be a three-dimensional cam, and the intake cam shaft 464 may also serve as a control shaft and move in the axial direction. Here, a straight spline 464b is provided at the end of the intake camshaft 464, and the straight spline 464b is engaged with the vane body 126 (FIG. 14) of the valve timing adjusting mechanism 58. Therefore, even if the vane body 126 cannot move in the axial direction within the short cylindrical casing, the intake camshaft 464 can move in the axial direction.
[0206]
Here, the shaft slide mechanism 100 is as described in the first embodiment. However, the cam frame 110 is connected to the intake camshaft 464 via a rolling bearing portion 466. Thus, the intake camshaft 464 can be moved in the axial direction without rotating the cam frame 110 with respect to the intake camshaft 464 that is interlocked with the rotation of the crankshaft via the valve timing adjusting mechanism 58.
[0207]
As shown in FIG. 34A, when the stopper arm 104d of the helical cam mechanism 104 is in contact with the minimum operating angle side stopper 104e, the intake camshaft 464 exists at the limit position in the L direction. Accordingly, the intake valve 2a is driven in contact with the low valve lift amount side of the intake cam 464a, and the valve lift amount and the valve operating angle become the smallest.
[0208]
When the spiral cam 108 is rotated by driving the motor from the state shown in FIG. 34A, the intake camshaft 464 moves in the H direction. As a result, the intake valve 2a comes into contact with a position away from the low valve lift amount side of the intake cam 464a, and the valve lift amount and the valve operating angle gradually increase.
[0209]
As shown in FIG. 34B, when the stopper arm 104d of the spiral cam mechanism 104 comes into contact with the maximum operating angle side stopper 104f, the intake camshaft 464 becomes the limit position in the H direction. Therefore, the intake valve 2a is driven in contact with the high valve lift amount side of the intake cam 464a, and the valve lift amount and the valve operating angle become the largest.
[0210]
In this way, the valve lift amount and valve working angle of the intake valve 2a can be adjusted as shown in FIG. Then, learning as described in the above embodiments is possible, and the same effect is produced.
[0211]
(B). In each of the above embodiments, the control shaft is moved in the axial direction by the combination of the motor and the spiral cam. However, the control shaft may be moved in the axial direction by a hydraulic piston, and the combination of the motor and the ball screw may be used. The control shaft may be moved in the axial direction.
[0212]
(C). In each of the above embodiments, the valve working angle has been described. However, as shown in FIG. 8, the valve operating angle (the rotation angle of the crankshaft from the valve opening to the valve closing) is linked to the valve lift amount, and therefore is described in the above embodiments. It is the same even if the expression “valve operating angle” is replaced with “valve lift amount”.
[0213]
(D). In each of the above embodiments, the valve working angle or valve lift amount is controlled for the intake valve 2a. However, the present invention can also be applied to the case where the valve working angle or valve lift amount of the exhaust valve 2b is variable.
[0214]
(E). In each of the above embodiments, the valve working angle or the valve lift amount is controlled. However, the present invention can be applied to the valve timing control.
That is, the valve timing adjusted by the valve timing adjusting mechanism 58 shown in FIG. 14 is obtained from the crank angle difference between the output pulse of the engine speed sensor 46 and the output pulse of the reference crank angle sensor 48. The learning value of the valve timing may be formally learned on either the most retarded side or the most advanced side of the valve timing and temporarily learned on the other side.
[0215]
(F). In each of the embodiments, the difference between the state quantity detected by the sensor and the known state quantity is set as the learning value and the provisional learning value, but in addition to this, when adding to the state quantity detected by the sensor, You may set the added value as a learning value and a provisional learning value so that the value after addition may become a difference in an allowable range with respect to a known state quantity.
[0216]
(G). In each of the above embodiments, the temporary learning position is the position of the maximum valve operating angle (maximum valve lift amount). For example, when the engine is stopped or the engine is started, the control shaft is connected to the maximum valve operating angle and the minimum valve operating angle. There is a case where mechanical restraint is performed at a position in the middle of the corner. In such a case, it is estimated that the control shaft is restrained at the intermediate position in the engine starting state, and the valve operating angle (valve lift amount) is also at the intermediate position. Therefore, at the time of starting, the known state quantity (rotation angle θv, slide amount SLv and valve operating angle VL) corresponding to this intermediate position and the actual rotation angle θv, slide amount SLv and valve operating angle VL detected by the sensor Based on the difference, a provisional learning value can be obtained.
[0217]
The mechanical restraint at such an intermediate position is, for example, provided with a pin hole on the peripheral surface of the control shaft, and the pin hole is pinned by a spring, hydraulic pressure, electromagnetic force, etc. from the cylinder head side when the engine is stopped or started. Is possible by inserting. The same applies to the valve timing, and it can be restrained by providing a pin hole in the vane body and inserting a pin from the casing side. By pulling the pin out of the pin hole by hydraulic pressure or electromagnetic force after startup, the valve operating angle (valve lift amount) or valve timing can be returned to a state where it can be arbitrarily adjusted.
[0218]
Mechanical restraint at the intermediate position of the control shaft is also possible by inserting and removing the intermediate stopper at the intermediate position between the minimum working angle side stopper and the maximum working angle side stopper with respect to the stopper arm of the helical cam mechanism. It is.
[0219]
(H). In step S109 in FIG. 15, step S307 in FIG. 20, and step S510 in FIG. 26, the presence or absence of contact and the presence or absence of a change in the slide amount SLv as a detection value are determined. In the case of the angular state, these determination processes may not be executed at the start, and temporary learning may be performed immediately. The same applies when mechanically constrained to an intermediate position at the time of stopping.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an engine and an ECU according to a first embodiment.
FIG. 2 is a longitudinal sectional view of the variable valve system of the engine.
FIG. 3 is a perspective view of the intermediate drive mechanism of the variable valve system.
FIG. 4 is a horizontal cutaway perspective view of the mediation drive mechanism.
FIG. 5 is a horizontal and vertical broken perspective view of the intermediate drive mechanism.
FIG. 6 is a drive explanatory diagram of the mediation drive mechanism.
FIG. 7 is a drive explanatory diagram of the mediation drive mechanism.
FIG. 8 is a graph for explaining changes in valve operating angle and valve lift amount by the mediation drive mechanism.
FIG. 9 is a perspective view of the shaft slide mechanism of the variable valve system.
FIG. 10 is a perspective view of a helical cam mechanism in the shaft slide mechanism.
FIG. 11 is a drive explanatory diagram of the spiral cam mechanism.
FIG. 12 is an explanatory diagram of a cam shape of a spiral cam of the spiral cam mechanism.
FIG. 13 is a graph showing the relationship between the detected rotation angle θv of the helical cam and the valve operating angle VL.
FIG. 14 is a diagram illustrating the configuration and driving of the valve timing adjusting mechanism of the variable valve system.
FIG. 15 is a flowchart of a valve operating angle control process executed by the ECU.
FIG. 16 is a flowchart of a minimum valve working angle learning process.
FIG. 17 is a timing chart showing an example of processing according to the first embodiment.
FIG. 18 is a timing chart showing an example of processing according to the first embodiment.
19 is a timing chart showing an example of processing according to Embodiment 1. FIG.
FIG. 20 is a flowchart of a valve working angle control process executed by the ECU according to the second embodiment.
FIG. 21 is a flowchart of the minimum valve working angle learning process.
FIG. 22 is a timing chart showing an example of processing according to the second embodiment.
FIG. 23 is a timing chart showing an example of processing according to the second embodiment.
24 is a timing chart illustrating an example of processing according to Embodiment 2. FIG.
FIG. 25 is a perspective view of the shaft slide mechanism of the third embodiment.
FIG. 26 is a flowchart of valve operating angle control processing executed by the ECU according to the third embodiment.
FIG. 27 is a graph showing the relationship between the slide amount SL of the control shaft and the valve operating angle VL.
FIG. 28 is a flowchart of a valve working angle control process executed by the ECU according to the fourth embodiment.
FIG. 29 is a flowchart of valve operating angle control processing executed by the ECU according to the fourth embodiment.
30 is a timing chart showing an example of processing according to Embodiment 4. FIG.
FIG. 31 is a timing chart showing an example of processing according to Embodiment 4;
FIG. 32 is a timing chart showing an example of processing according to Embodiment 4;
FIG. 33 is a perspective view showing an example of a variable valve system of another engine.
FIG. 34 is an explanatory diagram of a driving state of a variable valve system of another engine.
[Explanation of symbols]
2 ... Engine, 2a ... Intake valve, 2b ... Exhaust valve, 4 ... ECU, 6 ... Piston, 6a ... Crankshaft, 8 ... Cylinder block, 10 ... Cylinder head, 12 ... Combustion chamber, 14 ... Spark plug, 16 ... Fuel Injection valve, 18 ... intake port, 20 ... intake passage, 22 ... surge tank, 24 ... motor, 26 ... throttle valve, 28 ... throttle opening sensor, 30 ... intake air amount sensor, 32 ... intake air temperature sensor, 34 ... exhaust Port, 36 ... Exhaust passage, 38 ... Exhaust purification catalytic converter, 40 ... Air-fuel ratio sensor, 42 ... Accelerator pedal, 44 ... Accelerator opening sensor, 46 ... Engine speed sensor, 48 ... Reference crank angle sensor, 50 ... Rotation Angle sensor, 52 ... Cooling water temperature sensor, 54 ... Variable valve mechanism, 56 ... Valve operating angle adjustment mechanism, 58 ... Valve timing adjuster 60 ... Intermediate drive mechanism, 62 ... Roller rocker arm, 62a ... Rocker roller, 64 ... Suction cam shaft, 64a ... Suction cam, 66 ... Input section, 66a ... Housing, 66b ... Helical spline, 66c, 66d ... Arm, 66e ... shaft, 66f ... roller, 66g ... spring, 68 ... first swing cam, 68a ... housing, 68b ... helical spline, 68c ... bearing portion, 68d ... nose, 68e ... cam surface, 70 ... second swing cam, 70a ... housing, 70b ... helical spline, 70c ... bearing portion, 70d ... nose, 70e ... cam surface, 72 ... slider gear, 72a ... input helical spline, 72b ... small diameter portion, 72c ... first output helical spline, 72d ... Small diameter part, 72e ... Helical spline for second output, 72f ... Through hole 72g ... circumferential groove, 72h ... pin insertion hole, 80 ... support pipe, 80a ... long hole, 82 ... control shaft, 82a ... control pin, 82b ... support hole, 100 ... shaft slide mechanism, 102 ... motor, 102a ... small diameter gear 104 ... spiral cam mechanism, 104a ... large diameter gear, 104b ... cam shaft, 104c ... small diameter gear, 104d ... stopper arm, 104e ... minimum working angle side stopper, 104f ... maximum working angle side stopper, 106a ... large diameter gear, DESCRIPTION OF SYMBOLS 108 ... Spiral cam 108a ... Spiral cam surface, 110 ... Cam frame, 110a ... Roller, 110b ... Shaft, 120 ... OCV, 122 ... Vane type hydraulic rotation mechanism, 124 ... Casing, 124a, 124b ... Wall part, 126 ... Vane body, 126a ... shaft, 126c, 126d ... vane, 128, 130, 132, 134 ... Hydraulic chamber, 132a, 134a ... Spring, 136, 138 ... Stopper, 300 ... Shaft slide mechanism, 350 ... Slide sensor, 350a ... Rod-shaped core, 350b ... Coil, 464 ... Intake cam shaft, 464a ... Intake cam, 464b ... Straight spline, 466 ... Rolling bearing.

Claims (6)

In a variable valve mechanism that is driven by an actuator and changes the valve drive state of the internal combustion engine, a state quantity of valve drive is detected by a sensor, and control is performed to drive the actuator so that the state quantity becomes a target value. A variable valve mechanism control device for an internal combustion engine,
For use in the control, a state quantity detected by the sensor when the variable valve mechanism enters a preset reference valve drive state, and a known state quantity of the valve drive corresponding to the reference valve drive state, Reference valve drive state learning means for setting a learning value for compensating for an error between the actual valve drive state and the state quantity detected by the sensor based on the difference between
When the operating state of the internal combustion engine is in a reference engine state different from the engine state that becomes the reference valve driving state, the valve driving state of the internal combustion engine is estimated from the reference engine state, and the estimated valve driving state and the sensor Based on a difference from the detected state quantity, a temporary learning value that compensates for an error between the actual valve driving state and the state quantity detected by the sensor is set, and the temporary learning value is set as the reference valve driving state. Until the learning value is set by the learning means, provisional learning means used for the control,
A variable valve mechanism control apparatus for an internal combustion engine, comprising: In a variable valve mechanism that is driven by an actuator and changes the valve drive state of the internal combustion engine, a state quantity of valve drive is detected by a sensor, and control is performed to drive the actuator so that the state quantity becomes a target value. A variable valve mechanism control device for an internal combustion engine,
For use in the control, a state quantity detected by the sensor when the variable valve mechanism enters a preset reference valve drive state, and a known state quantity of the valve drive corresponding to the reference valve drive state, Reference valve drive state learning means for setting a learning value for compensating for an error between the actual valve drive state and the state quantity detected by the sensor based on the difference between
When the learning value by the reference valve driving state learning means is not set, when the operating state of the internal combustion engine is in a reference engine state different from the engine state in which the reference valve driving state is set , the valve of the internal combustion engine from the reference engine state Temporarily estimating the driving state and compensating for an error between the actual valve driving state and the state quantity detected by the sensor based on the difference between the estimated valve driving state and the state quantity detected by the sensor. Provisional learning means for setting a learning value and using it for the control;
A variable valve mechanism control apparatus for an internal combustion engine, comprising: 3. The variable valve mechanism control for an internal combustion engine according to claim 2, wherein the case where the learning value by the reference valve driving state learning means is not set is a case where memory of the learning value has disappeared. apparatus. 4. The variable valve mechanism control apparatus for an internal combustion engine according to claim 1, wherein the valve driving state is a state of a valve working angle or a valve lift amount . 5. The variable operation of the internal combustion engine according to claim 4 , wherein the reference valve drive state learning means sets a valve drive state in which a valve operating angle or a valve lift amount is minimized as the reference valve drive state. Valve mechanism control device. In claim 1, wherein the valve drive state, the variable valve mechanism control device for an internal combustion engine, which is a valve timing.

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