JP2008075562A - Control unit for variable valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit for a variable valve mechanism, which restrains troubles happened when a position of a control shaft early exceeds a pin connecting position. <P>SOLUTION: A hydraulic load applied on a pin is removed by making an OCV non-operate when changed from one valve variable range to a both-valves variable range (step 106). A designated time ΔT required for connection relief of the pin is calculated on the basis of water temperature Tw when the position of the control shaft is shifted to a large operation angle/large lifting amount side rather than a pin fitting position (step 110). An annealing control for the position of the control shaft (command value) is carried out between the designated time ΔT so that the position of the control shaft is not shifted to the large operation angle/large lifting amount side while the position of the control shaft exceeds the pin connecting position (step 112). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a variable valve mechanism that can mechanically change a valve opening characteristic, and more particularly, to a control device for a variable valve mechanism that can switch between a single valve variable control and a both valve variable control. .

  An apparatus having a variable valve mechanism that can mechanically change the valve opening characteristics of the valve is known (for example, see Patent Document 1). According to this device, both valve variable control for making the valve opening characteristics of both valves variable, and one valve is expressed as a large working angle and a large lift amount (hereinafter, “large working angle / large lift amount”). ) And the one-valve variable control in which the valve opening characteristic of the other valve is variable is selected by inserting and removing the pin. By executing the one-valve variable control, a swirling flow (hereinafter referred to as “swirl”) can be generated in the combustion chamber.

JP 2004-1000055 A

  Preventing sudden changes in the working angle / lift amount of a valve that is fixed to a large working angle / large lift amount during single valve variable control during and after switching from the double valve variable control to the single valve variable control. Is desirable. Therefore, when switching from the two-valve variable control to the one-valve variable control (that is, when a pin is inserted), the operation is often performed with a large working angle / a large lift amount.

  Further, the maximum working angle / maximum lift amount of the valve at the time of both-valve variable control is determined based on a request to secure a larger amount of intake air. On the other hand, the large working angle / large lift amount of the valve that is fixed during the one-valve variable control is determined based on requirements such as fuel consumption and exhaust performance. For this reason, normally, the large working angle / large lift amount during single valve variable control is made smaller than the maximum working angle / maximum lift amount during double valve variable control.

  By the way, there is a case where the single valve variable control is switched to the double valve variable control (for example, the state in which both valves are set to the maximum operating angle / maximum lift amount) as in the case of sudden acceleration. At this time, the control shaft is instantaneously rotated by the drive mechanism. Hereinafter, the control for rotating the control axis instantaneously (immediately) to the target position is referred to as “normal control”. Simultaneously with this normal control, the hydraulic load applied to the pin is released to release the connection by the pin, that is, to remove the pin from the pin hole.

  However, a certain amount of time is required until the hydraulic pressure applied to the pin decreases. For this reason, there is a case where the position of the control shaft exceeds the pin fitting position without the pin being pulled out. In this case, not the pressing force of the large lift cam but the pressing force of the main cam is transmitted to the large lift arm via the swing arm and the pin. Here, the cam height of the main cam is higher than that of the large lift cam. Then, the large lift roller provided on the large lift arm and the large lift cam are separated during the valve lift. Thereafter, when the hydraulic pressure applied to the pin decreases, the pin comes off and the large lift roller and the large lift cam come into contact again. At this time, there is a possibility that a hitting sound may be generated and an impact may be given to the roller surface of the large lift roller and the cam surface of the large lift cam.

  The present invention has been made in order to solve the above-described problems, and provides a control device for a variable valve mechanism that can suppress problems when the control shaft position exceeds the pin coupling position at an early stage. For the purpose.

In order to achieve the above object, the first aspect of the invention provides a one-valve variable control for fixing a valve opening characteristic of a switching target valve and changing a valve opening characteristic of another valve, the switching target valve, and the other A control device of a variable valve mechanism capable of switching between both valve variable control that makes both valve opening characteristics variable,
A swing member provided so as to be swingable according to the position of the control shaft and transmitting the pressing force of the main cam to the valve;
A large lift arm that transmits a pressing force of a large lift cam having a cam height higher than that of the main cam to the switching target valve during one-valve variable control;
A pin for connecting the swinging member and the large lift arm at the time of single valve variable control, and a pin for releasing the connection at the time of variable control of both valves;
Command value calculating means for calculating a command value of the position of the control axis;
Control axis driving means for driving the control axis based on the command value;
When switching from the one-valve variable control to the two-valve variable control, when changing the control shaft position to the larger working angle side than the pin connection position, it is the time required to release the connection by the pin A disconnection time calculating means for calculating the disconnection time;
The command value calculation means makes the command value so that the control shaft position does not exceed the pin connection position during the connection release time.

The second invention is the first invention, wherein
The command value calculation means, when switching from the one-valve variable control to the two-valve variable control, makes the change in the command value faster when the engine speed is low than when it is high. .

The third invention is the first or second invention, wherein
When switching from the one-valve variable control to the two-valve variable control, if the control shaft position is changed to the larger operating angle side than the pin connection position, the connection by the pin is released every predetermined operation time. It is further characterized by further comprising a prohibition unit for prohibiting connection release.

  According to the first invention, the control shaft position is prevented from exceeding the pin coupling position during the coupling release time by making the command value for the control shaft position. Therefore, it is possible to prevent the control shaft position from exceeding the pin connection position without releasing the connection by the pin. That is, the pressing force of the main cam is transmitted to the large lift arm via the swing arm and the pin without releasing the connection by the pin, and the large lift cam and the roller of the large lift arm are separated during the valve lift. It can be avoided. Therefore, it is possible to suppress problems when the control shaft position exceeds the pin connection position at an early stage.

  According to the second invention, when the engine speed is low, the change in the command value is made faster than when the engine speed is high. As a result, when the engine speed is low, it can be brought closer to the original control shaft position corresponding to the operating state earlier than when it is high, so that the operating angle and lift amount corresponding to the operating state can be set earlier. You can get closer. Therefore, it is possible to suppress the deterioration of combustion due to the smoothing control, and it is possible to suppress the deterioration of fuel consumption and exhaust emission characteristics.

  According to the third aspect of the present invention, when switching from single-valve variable control to double-valve variable control, when the control shaft position is changed to the larger operating angle side than the pin connection position, the connection by the pin is performed every predetermined operation time. Is prohibited. Thereby, not the pressing force of the second cam but the pressing force of the main cam is transmitted to the large lift arm via the swing arm and the pin. Therefore, the relationship between the force through the pin changes between the swing arm and the large lift arm every predetermined time. Therefore, uneven wear of the pin and the pin hole into which the pin is inserted can be prevented, and pin fixation can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[System configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. The system according to the first embodiment includes an internal combustion engine 1. The internal combustion engine 1 has a plurality of cylinders 2. FIG. 1 shows only one cylinder among a plurality of cylinders.

  The internal combustion engine 1 includes a cylinder block 4 having a piston 3 therein. The piston 3 is connected to the crankshaft 5 via a crank mechanism. In the vicinity of the crankshaft 5, a crank angle sensor 5A is provided. The crank angle sensor 5A is configured to detect the rotation angle (crank angle CA) of the crankshaft 5. The cylinder block 4 is provided with a water temperature sensor 6 for detecting the cooling water temperature Tw.

  A cylinder head 8 is assembled to the upper part of the cylinder block 4. A space from the upper surface of the piston 3 to the cylinder head 8 forms a combustion chamber 10. The cylinder head 8 is provided with an injector 9 that injects fuel directly into the combustion chamber 10. The cylinder head 8 is provided with a spark plug 11 that ignites the air-fuel mixture in the combustion chamber 10.

  The cylinder head 8 includes an intake port 12 that communicates with the combustion chamber 10. An intake valve 14 is provided at a connection portion between the intake port 12 and the combustion chamber 10. The system according to the first embodiment includes a plurality of intake valves 14 corresponding to a plurality of intake ports 12 provided for each cylinder. FIG. 1 shows one intake port 12 and one intake valve 14. A variable valve device 18 is provided between the intake valve 14 and an intake cam (main cam) 16 provided on the intake camshaft 15. The variable valve operating device 18 is configured such that the valve opening characteristics of the intake valve 14 can be mechanically changed. The details of the variable valve operating device 18 will be described later.

  An intake passage 19 is connected to the intake port 12. A surge tank 21 is provided in the middle of the intake passage 19. A throttle valve 22 is provided upstream of the surge tank 21. The throttle valve 22 is an electronically controlled valve that is driven by a throttle motor 23. The throttle valve 22 is driven based on the accelerator opening AA detected by the accelerator opening sensor 24. A throttle opening sensor 25 that detects the throttle opening TA is provided in the vicinity of the throttle valve 22. An air flow meter 26 is provided upstream of the throttle valve 22. The air flow meter 26 is configured to detect the intake air amount Ga. An air cleaner 27 is provided upstream of the air flow meter 26.

  The cylinder head 8 includes an exhaust port 28 that communicates with the combustion chamber 10. An exhaust valve 29 is provided at the connection between the exhaust port 28 and the combustion chamber 10. An exhaust passage 30 is connected to the exhaust port 28. A catalyst 34 for purifying exhaust gas is provided in the exhaust passage 30. An air-fuel ratio sensor 32 that detects the exhaust air-fuel ratio is provided upstream of the catalyst 34.

Further, the system of the present embodiment includes an ECU (Electronic Control Unit) 60 as a control device. In addition to the injector 9, the spark plug 11, the variable valve operating device 18, the throttle motor 23, a pump 82 and an OCV 84 (see FIG. 5) described later are connected to the output side of the ECU 60. On the input side of the ECU 60, in addition to the crank angle sensor 5A, the water temperature sensor 6, the accelerator opening sensor 24, the throttle opening sensor 25, the air flow meter 26, the air-fuel ratio sensor 31, a later-described hydraulic sensor 86 (see FIG. 5), etc. Is connected. The ECU 60 executes overall control of the internal combustion engine such as fuel injection control and ignition timing control based on the output of each sensor.
Further, the ECU 60 calculates the engine speed NE based on the output of the crank angle sensor 5A. Further, the ECU 60 calculates the load KL required for the internal combustion engine 1 based on the accelerator opening AA, the throttle opening TA, and the like.
Further, the ECU 60 calculates a required value for the swirl generated in the combustion chamber 10 according to the operating state (NE, KL). Further, the ECU 60 controls the valve opening characteristics of the intake valve 14 by controlling the position of the control shaft 41 in order to realize the required value of the swirl.

[Configuration of variable valve gear]
FIG. 2 is a perspective view for explaining the configuration of the variable valve operating device 18 in the system shown in FIG.
As shown in FIG. 2, the intake camshaft 15 is provided with two intake cams 16 and 17 per cylinder. The two intake valves 14L and 14R are arranged symmetrically about a first intake cam (hereinafter referred to as “main cam”) 16. Between the main cam 16 and the intake valves 14L and 14R, variable valve mechanisms 40L and 40R that link the lift movement of the intake valves 14L and 14R with the rotational movement of the main cam 16 are provided. On the other hand, the second intake cam (hereinafter referred to as “large lift cam”) 17 is arranged so as to sandwich the second intake valve 14 </ b> R with the main cam 16. Between the large lift cam 17 and the second intake valve 14R, a fixed valve mechanism 70 that links the lift movement of the second intake valve 14R with the rotational movement of the large lift cam 17 is provided. The variable valve operating device 18 selectively switches the interlocking destination of the lift interlock of the second intake valve 14R between the variable valve operating mechanism 40R and the fixed valve operating mechanism 70 using an arm coupling mechanism 72 described later. It is configured to be able to.

(1) Configuration of Variable Valve Mechanism FIG. 3 is a view for explaining the configuration of the variable valve mechanism 40 in the variable valve device 18 shown in FIG. Specifically, FIG. 3 is a view of the variable valve mechanism 40 as viewed from the axial direction of the intake camshaft 15. Since the left and right variable valve mechanisms 40L and 40R are basically symmetrical with respect to the main cam 16, the configuration thereof will be described without distinguishing between the left and right variable valve mechanisms 40L and 40R. To do. In the present specification and drawings, when the left and right variable valve mechanisms 40L and 40R are not distinguished, they are simply referred to as the variable valve mechanism 40. Similarly, the component parts of the variable valve mechanisms 40L, 40R and the symmetrically arranged parts such as the intake valves 14L, 14R are distinguished from each other except when it is necessary to distinguish between them. The symbol is not attached.

  As shown in FIG. 3, the rocker arm 35 is supported by the intake valve 14. The variable valve mechanism 40 is interposed between the main cam 16 and the rocker arm 35. The variable valve mechanism 40 is configured to continuously change the interlocking state between the rotational motion of the main cam 16 and the rocking motion of the rocker arm 35.

  The variable valve mechanism 40 has a control shaft 41 disposed in parallel with the intake camshaft 15. The control shaft 41 is rotationally driven by a drive mechanism (see FIG. 6) described later. As shown in FIG. 3, a control arm 42 is fixed to the control shaft 41 by a bolt 43. A part of the control arm 42 protrudes in the radial direction of the control shaft 41. An intermediate arm 44 is attached to the protruding portion of the control arm 42 by a pin 45. The pin 45 is disposed at a position eccentric from the center of the control shaft 41. Therefore, the intermediate arm 44 is configured to swing around the pin 45. Rollers 52 and 53, which will be described later, are rotatably provided at the distal end of the intermediate arm 44.

  A swing arm 50 is swingably supported on the control shaft 41. The swing arm 50 has a slide surface 50 a on the side facing the main cam 16. The slide surface 50 a is formed so as to contact the second roller 53. The slide surface 50 a is formed in a curved surface such that the distance from the main cam 16 gradually decreases as the second roller 53 moves from the distal end side of the swing arm 50 toward the axial center side of the control shaft 41. . The swing arm 50 has a swing cam surface 51 on the opposite side of the slide surface 50a. The rocking cam surface 51 has a non-working surface 51a formed so that the distance from the rocking center of the rocking arm 50 is constant, and a position farther from the non-working surface 51a from the shaft center of the control shaft 41. It is comprised with the action surface 51b formed so that distance may become far.

  A first roller 52 and a second roller 53 are disposed between the slide surface 50 a and the peripheral surface of the main cam 16. More specifically, the first roller 52 is disposed so as to contact the peripheral surface of the main cam 16. The second roller 53 is disposed so as to contact the slide surface 50 a of the swing arm 50. The first roller 52 and the second roller 53 are rotatably supported by a connecting shaft 54 fixed to the distal end portion of the intermediate arm 44. Since the intermediate arm 44 swings around the pin 45 as a fulcrum, the rollers 52 and 53 also swing along the slide surface 50 a and the peripheral surface of the main cam 16 while maintaining a certain distance from the pin 45.

  The swing arm 50 is formed with a spring seat 50b. One end of a lost motion spring 38 is hung on the spring seat 50b. The other end of the lost motion spring 38 is fixed to a stationary part of the internal combustion engine. The lost motion spring 38 is a compression spring. Due to the urging force received from the lost motion spring 38, the slide surface 50 a of the swing arm 50 is pressed against the second roller 53, and further, the first roller 52 is pressed against the main cam 16. Accordingly, the first roller 52 and the second roller 53 are positioned in a state where they are sandwiched from both sides by the slide surface 50a and the peripheral surface of the main cam 16.

  The rocker arm 35 is disposed below the swing arm 50. A rocker roller 36 is provided on the rocker arm 35 so as to face the swing cam surface 51. The rocker roller 36 is rotatably attached to an intermediate portion of the rocker arm 35. One end of the rocker arm 35 is supported by a valve shaft 14 a of the valve 14, and the other end of the rocker arm 35 is rotatably supported by a hydraulic lash adjuster 37. During the lift operation, the valve shaft 14a is biased by the valve spring 14b in the closing direction, that is, the direction in which the rocker arm 35 is pushed up. The rocker roller 36 is pressed against the swing cam surface 51 of the swing arm 50 by this urging force and a hydraulic lash adjuster 37.

  According to the configuration of the variable valve mechanism 40 described above, the pressing force of the main cam 16 is transmitted to the slide surface 50 a via the first roller 52 and the second roller 53 as the main cam 16 rotates. As a result, when the contact point between the swing cam surface 51 and the rocker roller 56 extends from the non-operation surface 51a to the operation surface 51b, the rocker arm 35 is pushed down and the valve 14 is opened.

  Further, according to the configuration of the variable valve mechanism 40, when the rotation angle (rotation position) of the control shaft 41 is changed, the position of the second roller 53 on the slide surface 50a changes, and the swing arm during the lift operation is changed. The swing range of 50 changes. More specifically, when the control shaft 41 is rotated in the counterclockwise direction in FIG. 3, the position of the second roller 53 on the slide surface 50 a moves to the tip side of the swing arm 50. Then, after the oscillating arm 50 starts the oscillating operation by transmitting the pressing force of the main cam 16, the rotation angle of the oscillating arm 50 that is actually required until the rocker arm 35 starts to be pressed is determined by the control shaft. 41 becomes larger as it rotates counterclockwise in FIG. That is, the operating angle and lift amount of the valve 14 can be reduced by rotating the control shaft 41 counterclockwise in FIG. Conversely, the operating angle and lift amount of the valve 14 can be increased by rotating the control shaft 41 in the clockwise direction.

(2) Configuration of Fixed Valve Mechanism Next, the configuration of the fixed valve mechanism 70 will be described with reference to FIGS. 2 and 4. FIG. 4 is an exploded perspective view showing the variable valve mechanism 40 and the fixed valve mechanism 70 shown in FIG.
As shown in FIG. 2, the fixed valve mechanism 70 is interposed between the large lift cam 17 and the second swing arm 50R. The fixed valve mechanism 70 interlocks the swing motion of the second swing arm 50 </ b> R with the rotational motion of the large lift cam 17. The fixed valve mechanism 70 includes a large lift arm 71 driven by the large lift cam 17 and an arm coupling mechanism 72 (see FIG. 4) for coupling the large lift arm 71 to the second swing arm 50R. The arm coupling mechanism 72 includes a pin 74, a hydraulic chamber 75, a pin hole 76, a return spring 77, and a piston 78, which will be described later.

The large lift arm 71 is arranged alongside the second swing arm 50R on the control shaft 41, and is rotatable independently of the second swing arm 50R. An input roller (hereinafter referred to as “large lift roller”) 73 that contacts the peripheral surface of the large lift cam 17 is rotatably supported by the large lift arm 71.
As shown in FIG. 4, a spring seat 71 a is formed on the large lift arm 71. Similar to the swing arm 50, a lost motion spring (not shown) is hung on the spring seat 71a. The large lift roller 73 is pressed against the peripheral surface of the large lift cam 17 by the spring force of the lost motion spring.

  The large lift arm 71 includes a pin 74 that can be taken in and out toward the second swing arm 50R. The large lift arm 71 is formed with a hydraulic chamber 75 having an opening on the second swing arm 50R side. A pin 74 is fitted in the hydraulic chamber 75. The hydraulic chamber 75 is connected to a hydraulic system described later. When the hydraulic pressure in the hydraulic chamber 75 is increased by a hydraulic system (see FIG. 5) described later, the pin 74 is pushed out from the hydraulic chamber 75 toward the second swing arm 50R by the hydraulic pressure.

  On the other hand, a pin hole 76 having an opening on the large lift arm 71 side is formed in the second swing arm 50R. The pin 74 and the pin hole 76 are arranged on the same arc centered on the control shaft 41. As a result, when the second swing arm 50R is positioned at a predetermined rotation angle with respect to the large lift arm 71, the position of the pin hole 76 and the position of the pin 74 are matched. A return spring 77 and a piston 78 as a lifter are disposed in the pin hole 76 from the back side.

FIG. 5 is a schematic diagram showing a configuration of a hydraulic system for operating the pin 74.
As shown in FIG. 5, an oil passage 81 is formed in the control shaft 41. The oil passage 81 is connected to the hydraulic chamber 75, a sliding gap between the control shaft 41 and the large lift arm 71, and a sliding gap between the control shaft 41 and the second swing arm 50R. The oil passage 81 is connected to a pump 82. A discharge path 83 is connected in the middle of the oil path 81. An oil control valve (hereinafter referred to as “OCV”) 84 is provided at a connection portion between the oil passage 81 and the discharge passage 83. The OCV 84 is an electromagnetically driven valve that operates when a voltage is applied from the ECU 60, for example. The discharge path 83 is provided with an orifice 85 for adjusting the flow rate of the lubricating oil. In addition, the hydraulic system includes a hydraulic sensor 86. The oil pressure sensor 86 is configured to detect the oil pressure in the oil passage 81.

While no voltage is applied from the ECU 60 to the OCV 84 and the OCV 84 is not operating, the lubricating oil pressurized by the pump 82 is discharged through the discharge path 83. At this time, the hydraulic pressure applied to the pin 74 is reduced. That is, the hydraulic load applied to the pin 74 is released.
On the other hand, when a voltage is applied from the ECU 60 to the OCV 84 and the OCV 84 is activated, the lubricating oil pressurized by the pump 82 is supplied to the sliding gap and the hydraulic chamber 75 through the oil passage 81. At this time, the hydraulic pressure applied to the pin 74 increases. That is, the hydraulic load applied to the pin 74 is maintained.
Thus, the pin 74 can be operated by controlling the hydraulic pressure in the hydraulic chamber 75 (that is, the hydraulic pressure applied to the pin 74) using the OCV 84.

FIG. 6 is a schematic view showing a drive mechanism of the control shaft 41.
As shown in FIG. 6, a worm wheel 92 is fixed near the end of the control shaft 41. Although illustration is omitted, both end surfaces of the worm wheel 92 are held between thrust receiving portions. The thrust receiving portion restricts the position of the worm wheel 92 in the thrust direction (that is, the axial direction of the control shaft 41). A worm gear 94 is disposed so as to be engaged with the worm wheel 92. The worm gear 94 is rotatably fixed to the housing 96 via bearings 95A and 95B.

  The worm gear 94 is fixed to the output shaft of the electric motor 98. A rotation angle sensor 99 for detecting the rotation angle of the electric motor 98 is provided on the output shaft of the electric motor 98. The electric motor 98 and the rotation angle sensor 99 are connected to the ECU 60. The ECU 60 performs drive control of the electric motor 98 based on the rotation angle detected by the rotation angle sensor 99. The driving force of the electric motor 98 is transmitted to the control shaft 41 via the worm gear 94 and the worm wheel 92. That is, the control shaft 41 can be rotated by driving the electric motor 98. Therefore, the position of the control shaft 41 (hereinafter referred to as “control shaft position S”) can be controlled by controlling the drive amount of the electric motor 98 by the ECU 60.

[Features of Embodiment 1]
(Single valve variable control)
In the above system, when the second swing arm 50R is positioned at a predetermined rotation angle with respect to the large lift arm 71, the positions of the pin 74 and the pin hole 76 coincide. When the position of the pin hole 76 and the position of the pin 74 coincide, the pin 74 contacts the piston 78. At this time, if the force in which the hydraulic pressure in the hydraulic chamber 75 pushes the pin 74 is greater than the force by which the return spring 77 pushes the piston 78, the pin 74 pushes the piston 78 into the back of the pin hole 76. The pin hole 76 is entered. That is, the pin 74 can be inserted into the pin hole 76 by operating the OCV 84 to increase the hydraulic pressure in the hydraulic chamber 75. When the pin 74 is inserted into the pin hole 76, the second swing arm 50R and the large lift arm 71 are connected. Thereby, the interlocking destination of the lift movement of the second intake valve 14R can be switched from the variable valve mechanism 20R to the fixed valve mechanism 70.

  In this case, the rotational motion of the intake camshaft 15 is transmitted from the large lift cam 17 to the second swing arm 50R via the large lift arm 71. The opening characteristics of the second intake valve 14R are mechanically determined by the shapes and positional relationships of the large lift cam 17, the large lift arm 71, and the second swing arm 50R, and are always constant regardless of the rotation angle of the control shaft 41. Fixed to valve characteristics (large working angle / large lift). That is, constant control is performed to make the valve opening characteristic of the second intake valve 14R constant.

On the other hand, the rotational motion of the intake camshaft 15 is transmitted from the main cam 16 to the first swing arm 50L via the first roller 52 and the second roller 53L. Therefore, the valve opening characteristic of the first intake valve 14L changes in conjunction with the rotation angle of the control shaft 41.
Therefore, one-valve variable control is performed in which only the valve opening characteristic of the first intake valve 14L can be changed in conjunction with the rotation angle of the control shaft 41 while the valve opening characteristic of the second intake valve 14R is fixed. Can do.

(Double valve variable control)
On the other hand, the pin 74 can be removed from the pin hole 76 by deactivating the OCV 84 and lowering the hydraulic pressure in the hydraulic chamber 75. Thereby, the connection between the large lift arm 71 and the second swing arm 50R is released. Therefore, the interlocking destination of the lift movement of the second intake valve 14R can be switched from the fixed valve mechanism 70 to the variable valve mechanism 20R.

In this case, the rotational movement of the cam shaft 15 is transmitted from the main cam 16 to the slide surfaces 50a of the first and second swing arms 50L and 50R via the first and second rollers 52 and 53. Therefore, the valve opening characteristics of the first intake valve 14L and the second intake valve 14R are the same and change in conjunction with the rotation of the control shaft 41. That is, variable control is performed to vary the valve opening characteristic of the second intake valve 14R.
Therefore, the variable valve control can be performed in which the valve opening characteristic of the first intake valve 14L and the valve opening characteristic of the second intake valve 14R can be changed together in conjunction with the rotation angle of the control shaft 41.

FIG. 7 is a diagram illustrating an example of a single valve variable region and a dual valve variable region.
As shown in FIG. 7, the valve opening characteristic control of the intake valve 14 is determined by the operating region determined by the engine speed NE and the load KL.

  In the operation range from low load to medium load and from low rotation to medium rotation, that is, the single valve variable region shown in FIG. 7, it is required to generate a swirl, and thus the single valve variable control is performed. In this one-valve variable region, the second swing arm 50 </ b> R and the large lift arm 71 are connected by a pin 74. For this reason, the valve opening characteristic of the second intake valve 14R is fixed to a large working angle / a large lift amount. The operating angle / lift amount of the first intake valve 14L is continuously changed according to the rotation angle of the control shaft 41. That is, by controlling the rotation angle of the control shaft 41 by the ECU 60 according to the operating state of the internal combustion engine (engine speed NE, load KL), the swirl optimal for the operating state is generated while being continuously changed. Can do. Thereby, the combustion state of an internal combustion engine can be made favorable. By making the combustion state good, the fuel consumption can be improved and the exhaust emission can be reduced.

On the other hand, since it is not required to generate swirl in the operation region such as high rotation / high load, low rotation / high load, low rotation / low load (idle), that is, the both valve variable region shown in FIG. Control is performed. In this variable valve variable region, the pin 74 is accommodated in the hydraulic chamber 75 of the large lift arm 71. For this reason, the working angle / lift amount of the second intake valve 14R as well as the first intake valve 14L is continuously changed. Therefore, according to the rotation angle of the control shaft 41, the valve opening characteristics of both intake valves 14L, 14R are both equal lift amount / working angle. For example, since it is required to obtain a large amount of intake air in the high rotation / high load region of both valve variable regions, the valve opening characteristics of both intake valves 14L and 14R are both large working angle / large lift amount. Be controlled.
As shown in FIG. 7, the boundary between the both valve variable region and the one-valve variable region is a pin operating line where the pin 74 is inserted into and removed from the pin hole 76.

By the way, the position of the pin hole 76 in the second swing arm 50R can be arbitrarily determined. That is, the operating angle / lift amount of the intake valves 14L and 14R when the pin 74 is inserted and removed can be arbitrarily determined.
FIG. 8 is a diagram showing the operating angle / lift amount of the intake valves 14L and 14R when the pins are fitted (when the pins are connected). In FIG. 8, the broken line A represents the maximum working angle / maximum lift amount that can be realized on the mechanism of the variable valve mechanism 40. The broken line D represents the minimum working angle / minimum lift amount that can be realized in the mechanism of the variable valve mechanism 40. A solid line B represents the maximum operating angle / maximum lift amount during the variable valve control. The maximum operating angle / maximum lift amount represented by the solid line B is determined from the design specifications of the components of the intake valve 14 and the like.

In FIG. 8, a solid line E represents the operating angle / lift amount of the second intake valve 14R during the one-valve variable control. The working angle / lift amount represented by the solid line E is determined from the requirements of fuel consumption and exhaust performance, that is, the requirements of swirl generated in the combustion chamber 10.
In general, as shown in FIG. 8, the operating angle / lift amount E at the time of single valve variable control is made smaller than the maximum operating angle / maximum lift amount B at the time of variable valve control.

  In FIG. 8, a thick solid line C represents the working angle / lift amount when the pin is fitted. The operating angle / lift amount represented by the thick solid line C is the maximum operating angle / maximum lift amount during the double valve variable control represented by the solid line B and the operating angle during the single valve variable control represented by the solid line E. / Set between the lift amount. Thereby, it is possible to prevent a sudden change in the operating angle and lift amount of the second intake valve 14R before and after switching from the both-valve variable control to the one-valve variable control. Therefore, the load applied to the components of the variable valve mechanism 40 at this time can be suppressed.

  By the way, from the state where the first intake valve 14L has a small working angle / small lift amount in the one-valve variable region, both the intake valves 14L, 14R in both valve variable regions rapidly change to the state where the maximum working angle / maximum lift amount is reached. May switch. This switching is performed at the time of rapid acceleration, for example. In this case, using the drive mechanism shown in FIG. 6, the position of the control shaft 41 is instantaneously rotated from the position of the small operating angle to the position of the maximum operating angle. By the rotation of the control shaft 41, the positions of the control arm 42 and the swing arm 50 are changed, and the maximum operating angle / maximum lift amount of the both-valve variable control is set. At the same time, in order to remove the pin 74 from the pin hole 76, the OCV 84 is deactivated to release the hydraulic pressure applied to the pin 74.

  However, it takes some time before the hydraulic pressure applied to the pin 74 decreases. Therefore, when the control shaft 41 is instantaneously rotated to the target position as in the normal control, the pin 74 is not completely pulled out from the pin hole 76 (that is, the second swing arm 50R and the large lift arm 71 are pinned). 74 may remain in the maximum operating angle / maximum lift amount state of the variable control of both valves. In this case, not the pressing force of the large lift cam 17 but the pressing force of the main cam 16 is transmitted to the large lift arm 71 via the second swing arm 50R and the pin 74. Then, the large lift cam 17 and the large lift roller 73 provided on the large lift arm 71 are temporarily separated during the valve lift. For this reason, when the oil pressure is sufficiently lowered and the pin 74 is pulled out and the large lift roller 73 and the large lift cam 17 are brought into contact with each other again, a hitting sound may be generated. Furthermore, the roller surface and the cam surface may be damaged by the impact caused by the re-contact.

  Therefore, in the first embodiment, the control shaft position is the pin for a predetermined time required for the pin 74 to be removed from the pin hole 76 (that is, a predetermined time required for the hydraulic pressure applied to the pin 74 to be sufficiently low). “Annealing control” shown in FIG. 10 is performed so that the large working angle / large lift side is not exceeded beyond the fitting position. That is, the change of the control axis is delayed as compared with the normal control.

  FIG. 9 is a diagram for explaining normal control of the control shaft position S (command value Sord). FIG. 10 is a diagram for explaining the smoothing control of the control shaft position S (command value Sord) according to the first embodiment. The control shaft position S can be detected based on the output of the rotation angle sensor 99. 9 and 10 are diagrams showing a case where the target position Strg determined in accordance with the operating state is on the larger operating angle / large lift amount side than the pin fitting position Sins. 9 and 10, “S0” represents the control axis position immediately before switching to the both-valve variable control (for example, time t0 when the one-valve variable control is executed). At time t1, switching from single valve variable control to double valve variable control is started. That is, at this time t1, the OCV 84 is deactivated.

  According to the normal control shown in FIG. 9, the command value Sord indicated by the broken line reaches the target value Strg at time t2. The time from time t1 to time t2 is, for example, several milliseconds. Thereafter, at time t3, the actual control axis position S indicated by the bold line in the figure reaches the target value Strg. However, at this time t3, the predetermined time ΔT has not elapsed since the switching start time t1. The predetermined time ΔT is a time required for the pin 74 to be completely removed, that is, a time required for the hydraulic pressure applied to the pin 74 to be sufficiently lowered, and is several tens of milliseconds, for example. Therefore, at time t3, the pin 74 cannot be removed from the pin hole 76. When the actual control shaft position S is larger than the pin fitting position Sins and the large working angle / large lift amount side in such a state that the pin 74 is not completely pulled out, the pressing force of the large lift cam 17 is applied to the large lift arm 71 as described above. Will be transmitted. As a result, a situation occurs in which the large lift roller 73 and the large lift cam 17 are temporarily separated during the valve lift.

On the other hand, according to the smoothing control shown in FIG. 10, at the time t4 when the predetermined time ΔT elapses from the switching start time t1, the actual control shaft position S indicated by the bold line in the figure is the pin fitting position Sins. Will not exceed. In the first embodiment, at time t4, the command value Sord is controlled so as not to exceed the pin fitting position Sins. This predetermined time ΔT is mechanically determined by the diameter and length of the pin 74, the spring force, etc., and has a correlation with the cooling water temperature Tw. Therefore, the predetermined time ΔT corresponding to the cooling water temperature Tw can be obtained by referring to the map that defines the relationship between the cooling water temperature Tw and the predetermined time ΔT.
The command value Sord at the elapsed time t from the switching start time t1 to the both-valve variable control is obtained by the following equation (1).
Sord = SO + a × t ^k ... (1)
As described above, “SO” in the above formula is the actual control shaft position immediately before switching to the both-valve variable control. In the above formula, “a” and “k” are constants.

  According to the first embodiment, the command value Sord at the elapsed time t from the switching start time t1 is obtained according to the above equation (1). As a result, even if the target position Strg is on the larger working angle / large lift side than the pin fitting position Sins, the control shaft position S exceeds the pin fitting position Sins until the pin 74 is securely pulled out. Not to be controlled. That is, it is possible to avoid a situation in which the control shaft position S exceeds the pin fitting position Sins while the pin 74 is not completely removed from the pin hole 76. For this reason, the situation where the large lift arm 71 is driven by the main cam 16, that is, the situation where the large lift roller 73 and the large lift cam 17 are temporarily separated during the valve lift can be avoided. Therefore, it is possible to avoid the occurrence of hitting sound that occurs when the large lift roller 73 and the large lift cam 17 are recontacted and damage to the roller surface and the cam surface due to the recontact.

[Specific Processing in Embodiment 1]
FIG. 11 is a flowchart showing a routine executed by the ECU 60 in the first embodiment.
According to the routine shown in FIG. 11, first, based on the engine operating state (NE, KL), it is determined whether or not it is a one-valve variable region (step 100). The ECU 60 stores a map as shown in FIG. 7, and can execute the determination process in step 100 by referring to the map. If it is determined in step 100 that the region is not a one-valve variable region, that is, if it is determined that it is a both-valve variable region, the control shaft position S (command value Sord) is instantaneously set to the target position Strg. Control is performed (step 102).

  On the other hand, if it is determined in step 102 that the region is the one-valve variable region, it is then determined whether or not the two-valve variable region has been changed (step 104). In step 104, it is determined whether or not the two-valve variable region has been changed due to a change in the engine operating state in accordance with the accelerator operation of the vehicle driver after the determination in step 100 is "YES". In step 104, the same map as in step 100 is referred to. If it is determined in step 104 that the valve has not changed to the two-valve variable region, that is, if it is determined that the one-valve variable region remains, the normal control is performed (step 102).

  If it is determined in step 104 that both valve variable regions have been changed, the hydraulic load applied to the pin 74 is released by deactivating the OCV 84 (step 106). Thereafter, it is determined whether or not the control shaft position is rotated to the larger working angle / large lift amount side than the pin fitting position (step 108). In this step 108, it is determined whether or not the target control shaft position determined based on the engine operating state (NE, KL) is on the larger operating angle / large lift side than the pin fitting position.

  If it is determined in step 108 that the control shaft position is not rotated to the larger working angle / large lift amount side than the pin fitting position, the normal control is executed (step 102). This is because the control shaft position S does not exceed the pin fitting position Sins without completely removing the pin 74 from the pin hole 76, and the large lift roller 73 and the large lift cam 17 cannot be separated.

  On the other hand, if it is determined in step 108 that the control shaft 41 is rotated to the larger working angle / large lift amount side than the pin fitting position, the water temperature Tw is referred to by referring to a map stored in the ECU 60 in advance. A predetermined time ΔT based on the above is calculated (step 110). According to the map, the higher the water temperature Tw, the shorter the predetermined time ΔT is calculated. Next, during the predetermined time ΔT calculated in step 110, the control shaft position S is smoothed so that the control shaft position S does not exceed the pin fitting position Sins (step 112). In this step 112, the command value Sord is calculated according to the above equation (1) using the control shaft position S0 immediately before the start of switching to the both-valve variable control and the elapsed time t from the start of switching. Based on this command value Sord, the electric motor 98 is driven.

  As described above, according to the routine shown in FIG. 11, the target position Strg is on the larger operating angle / large lift amount side than the pin fitting position Sins when switching from the one-valve variable control to the both-valve variable control. In this case, smoothing control of the control axis position S (command value Sord) is executed. Specifically, the control shaft position S is controlled so as not to exceed the pin fitting position Sins until a predetermined time ΔT elapses after the OCV 84 is deactivated. Therefore, the situation where the large lift arm 71 is driven by the main cam 16, that is, the situation where the large lift roller 73 and the large lift cam 17 are temporarily separated during the valve lift can be avoided. Therefore, it is possible to avoid the occurrence of hitting sound that occurs when the large lift roller 73 and the large lift cam 17 are recontacted and damage to the roller surface and the cam surface due to the recontact.

  By the way, in the first embodiment, as shown in FIG. 10, control is performed so that the command value Sord does not exceed the pin fitting position Sins until a predetermined time ΔT has elapsed from the switching start time t1 to the both-valve variable control. Has been. However, even if the command value Sord exceeds the pin fitting position Sins when the predetermined time Δ has elapsed, if the actual control shaft position S does not exceed the pin fitting position Sins, the same effect as in the first embodiment is achieved. Can be obtained.

  In the first embodiment, the valve opening characteristic is changed by rotating the control shaft 41 to change the posture of the control arm 40 and the swing arm 50. However, the valve opening characteristic is changed. The mechanism for doing this is not limited to this. For example, the present invention can also be applied to a mechanism that changes the posture of the swing arm by driving the control shaft 41 in the axial direction.

In the first embodiment, the valve 14R is the “switching target valve 14R” in the first invention, the valve 14L is the “other valve” in the first invention, and the control shaft 41 is the first invention. In the “control shaft”, the main cam 16 is the “main cam” in the first invention, the large lift cam 17 is the “large lift cam” in the first invention, and the large lift arm 71 is the “large lift arm” in the first invention. And the pin 74 corresponds to the “pin” in the first invention.
Further, in the first embodiment, the ECU 60 executes the process of step 110, so that the “disconnection time calculation means” in the first invention executes the process of step 112. “Command value calculation means” is realized.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. The system of the second embodiment can be realized by causing the ECU 60 to execute a routine shown in FIG. 14 described later using the hardware configuration shown in FIGS. 1 to 6.

[Features of Embodiment 2]
In the first embodiment, the smoothing control of the control shaft position command value Sord is performed so that the control shaft position S does not exceed the pin fitting position Sins until the predetermined time ΔT has elapsed after the OCV 84 is deactivated. It has been implemented (see FIG. 10).

By the way, the engine speed (hereinafter referred to as “the engine speed at the time of switching”) when switching from the one-valve variable control to the two-valve variable control is required by the driving state before switching and the vehicle driver. Depending on the driving state, that is, depending on the driving pattern.
FIG. 12 is a diagram showing the relationship between the operation pattern and the engine speed at the time of switching. FIG. 12 shows two operation patterns (first and second operation patterns) and switching engine speeds NE1 and NE2 in each operation pattern. The engine speed NE1 and NE2 at the time of switching are engine speeds at the intersections (points indicated by black circles in FIG. 12) between the first and second operation patterns and the pin operation lines. The engine speed NE1 at the time of switching in the first operation pattern is lower than the engine speed NE2 in the second operation pattern.

  Here, when the engine speed at the time of switching is low, the collision speed at the time of re-contact between the large lift roller 73 and the large lift cam 17 is slower than when the engine speed is high. When the engine speed at the time of switching is low, the hitting sound and impact at the time of re-contact are smaller than when the engine speed is high. When the hitting sound and impact at the time of re-contact are small as described above, re-contact between the large lift lift roller 73 and the large lift cam 17 is allowed, and the control shaft position S is quickly set to the original target position Strg corresponding to the operating state. It is desirable from the viewpoint of fuel consumption and exhaust characteristics to be close to.

  Therefore, in the second embodiment, when the engine speed at the time of switching is low (that is, when the collision speed at the time of re-contact is relatively slow), re-contact between the large lift lift roller 73 and the large lift cam 17 is permitted. However, the control shaft position S is driven to the target position Strg at an early stage. That is, the smoothing control of the command value Sord is made different between when the engine speed at the time of switching is low (that is, when the collision speed at the time of re-contact is relatively slow) and when the engine speed at the time of switching is high. To do.

  FIG. 13 is a diagram for explaining the smoothing control of the command value Sord performed in the second embodiment. As shown in FIG. 13, when the engine speed at the time of switching is high (that is, when the collision speed at the time of re-contact is high), as described in the first embodiment, the command is issued for a predetermined period ΔT. Smoothing control is performed so that the value Sord does not exceed the pin fitting position Sins.

  On the other hand, when the engine speed at the time of switching is low (that is, when the collision speed at the time of recontact is low), the change in the command value Sord is made faster than when the engine speed is high. In order to speed up the change of the command value Sord in this way, for example, a method of changing the constants a and k in the above equation (1) or a method of adding a correction term to the above equation (1) can be considered. In the second embodiment, the constant a is increased, the constant k is decreased, or both are performed so that the change in the command value Sord is accelerated when the engine speed at the time of switching is low.

  Thus, when the engine speed at the time of switching is low, the command value Sord is not changed instantaneously as in normal control, but the command value Sord reaches the target position Strg earlier than when the engine speed at the time of switching is high. . Therefore, when the engine speed at the time of switching is low, the control shaft position S corresponds to the operating state (NE, KL) as compared with a high case while allowing the large lift roller 73 and the large lift cam 17 to re-contact with each other. It is possible to approach the original target position Strg early. For this reason, it is possible to suppress the deterioration of combustion due to the execution of the annealing control, and it is possible to suppress the deterioration of fuel consumption and exhaust emission characteristics.

[Specific Processing in Second Embodiment]
FIG. 14 is a flowchart showing a routine executed by the ECU 60 in the second embodiment.
According to the routine shown in FIG. 14, similarly to the routine shown in FIG. 11, it is determined whether or not it is a one-valve variable region (step 100). It is discriminated whether or not the valve has changed to the both valve variable region (step 104). When the one-valve variable region is changed to the both-valve variable region, the hydraulic load applied to the pin 74 is released by deactivating the OCV 84 (step 106). Next, it is determined whether or not the control shaft position S is set to a larger operating angle / large lift amount side than the pin fitting position Sins (step 108).

  If it is determined in step 100 that it is not a single-valve variable region, if it is determined in step 104 that it has not changed to the double-valve variable region, and if the control shaft position S is determined to be a pin fitting position in step 108 When it is determined that the larger operating angle / large lift amount side is not set than Sins, normal control of the control shaft position S is performed (step 102).

  If it is determined in step 108 that the control shaft position S is set to a larger working angle / large lift amount side than the pin fitting position Sins, it is determined whether or not the engine speed at the time of switching is smaller than a reference value NEth. (Step 112). This reference value NEth is a value for determining whether or not the impact speed at the time of re-contact between the large lift roller 73 and the large lift cam 17 is slow, and whether a hitting sound or impact at the time of re-contact is allowed.

  If it is determined in step 112 that the engine speed during switching is equal to or greater than the reference value NEth, a predetermined time Δ based on the water temperature Tw is calculated in the same manner as in the routine shown in FIG. 11 (step 110). Thereafter, smoothing control of the control shaft position S is performed (step 116). In this step 116, during the predetermined time ΔT calculated in the above step 110, the command value according to the above equation (1) is used using the constants a2 and k2 so that the control shaft position S does not exceed the pin fitting position Sins. Sord is required. As a result, the command value Sord changes as represented by “smoothing control during high rotation” in FIG.

  On the other hand, if it is determined in step 112 that the engine speed at the time of switching is lower than the reference value NEth, smoothing control of the control shaft position S is performed according to the above equation (1) using the constants a1 and k1. (Step 118). The constant a1 selected in step 118 is larger than the constant a2 selected in step 116. In addition, the constant k1 selected in step 114 is smaller than the constant k2 selected in step 116. Therefore, according to this step 118, the change in the command value Sord is faster than that in the above-mentioned step 116, as represented by “smoothing control at low rotation” in FIG. For this reason, the control shaft position S reaches the target position Strg at an early stage.

  As described above, according to the routine shown in FIG. 14, when the engine speed at the time of switching is lower than the reference value NEth, the change in the command value Sord is made faster than when it is higher. As a result, the control shaft position S is brought closer to the original target position Strg corresponding to the operating state (NE, KL) at an early stage as compared with a high case while allowing the large lift roller 73 and the large lift cam 17 to re-contact. Can do. For this reason, it is possible to suppress the deterioration of combustion due to the execution of the annealing control, and it is possible to suppress the deterioration of fuel consumption and exhaust emission characteristics.

  In the second embodiment, the constant a1, k1 or the constant a2, k2 is selected according to the result of comparing the engine speed at switching and the reference value NEth. The engine speed may be subdivided and constants a and k may be selected accordingly. Further, these constants a and k may be obtained by a function with respect to the engine speed at the time of switching.

  Further, when the engine speed at the time of switching is significantly lower than the reference value NEth, the collision speed at the time of re-contact between the large lift lift roller 73 and the large lift cam 17 is also significantly reduced. Therefore, in this case, the command value Sord may be instantaneously changed to the target position Strg as in the normal control shown in FIG.

  In the second embodiment, the “command value calculation means” according to the second aspect of the present invention is realized by the ECU 60 executing the process of step 118.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. 15 and FIG. The system of the third embodiment can be realized by causing the ECU 60 to execute a routine shown in FIG. 16 described later using the hardware configuration shown in FIGS. 1 to 6.

[Features of Embodiment 3]
FIG. 15 is a diagram illustrating a force relationship between the swing arm 50 </ b> R and the large lift arm 71 via the pin 74. Specifically, FIG. 15A is a diagram showing a force relationship at the time of one-valve variable control, and FIG. 15B shows a large working angle / large at the time of both-valve variable control without the pin 74 being removed. It is a figure which shows the force relationship in the case of being made into the lift amount state.

  As shown in FIG. 15A, when the one-valve variable control is being performed, the second swing arm 50 </ b> R and the large lift arm 71 are connected by the pin 74. At this time, the large lift arm 71 is driven by the large lift cam 17. The pressing force applied to the large lift arm 71 is transmitted to the second swing arm 50R via the pin 74 and becomes a force for pressing the rocker roller 36. That is, as indicated by an arrow in the drawing, the pin 74 is pushed by the large lift arm 71, and the second swing arm 50R is pushed by the pin 74.

  Thus, during the one-valve variable control, a force is applied to the same surface of the pin 74 as shown in FIG. For this reason, uneven wear (including surface damage and deformation) occurs at the pin 74 and the pin hole 76. Furthermore, when the pin 74 is repeatedly inserted and removed, sludge accumulates at the same location of the pin hole 76, and the pin 74 may be fixed by the sludge.

  Therefore, in the third embodiment, when switching from the single valve variable control to the large working angle / large lift amount side from the pin fitting position of the double valve variable control, the pin 74 is not pulled out every predetermined operation time. To. Then, as shown in FIG. 15B, the second swing arm 50R is driven by the main cam 16 in a state where the second swing arm 50R and the large lift arm 71 are connected by the pin 74. The pressing force applied to the second swing arm 50 </ b> R becomes a force for pressing the rocker roller 36 and is transmitted to the large lift arm 71 through the pin 74 as indicated by an arrow in the drawing. That is, the pin 74 is pushed by the second swing arm 50R, and the large lift arm 71 is pushed by the pin 74.

  Thus, the location where the force is applied to the pin 74 can be made different from the one-valve variable control shown in FIG. As a result, the pin 74 can be rotated in the pin hole 76. Therefore, the occurrence of uneven wear at the pin 74 and the pin hole 76 can be prevented. Furthermore, since it is possible to avoid the concentration of sludge generation locations in the pin hole 76, the pin 74 can be prevented from sticking.

[Specific Processing in Embodiment 3]
FIG. 16 is a flowchart showing a routine executed by the ECU 60 in the third embodiment.
According to the routine shown in FIG. 16, as in the routine shown in FIG. 11, it is determined whether or not it is a one-valve variable region (step 100). It is discriminated whether or not the valve has changed to the both valve variable region (step 104). When the one-valve variable region is changed to the both-valve variable region, it is determined whether or not the control shaft position S is set to the larger operating angle / large lift amount side than the pin fitting position Sins (step 108).

  If it is determined in step 100 that it is not a single-valve variable region, if it is determined in step 104 that it has not changed to the double-valve variable region, and if the control shaft position S is determined to be a pin fitting position in step 108 When it is determined that the larger operating angle / large lift amount side is not set than Sins, normal control of the control shaft position S is performed (step 102).

  If it is determined in step 108 that the control shaft position S is set to a larger working angle / large lift amount side than the pin fitting position Sins, it is determined whether or not a predetermined operation time has elapsed (step 120). . In this step 120, it is determined whether or not the operation time counted after being reset in step 128 described later has exceeded a reference value. This reference value can be determined in advance according to the length and diameter of the pin 74, the diameter of the pin hole 76, the hydraulic load applied to the pin 74, and the like.

  If it is determined in step 120 that the predetermined operation time has not elapsed, it is determined that it is not necessary to rotate the pin 74 in the pin hole 76. In this case, as in the routine shown in FIG. 11, the hydraulic load applied to the pin 74 is released by deactivating the OCV 84 (step 106).

  On the other hand, if it is determined in step 120 that the predetermined operation time has elapsed, it is determined that the pin 74 needs to be rotated in the pin hole 76. In this case, the hydraulic load applied to the pin 74 is maintained by keeping the OCV 84 actuated to maintain the force relationship as shown in FIG. 14B (step 122). After that, due to the change of the driving state according to the accelerator operation of the vehicle driver, the control shaft position S is changed to the smaller working angle / small lift amount side than the pin fitting position Sins with the both valve variable regions remaining. Whether or not (step 124). If it is determined in step 124 that the control shaft position S has not changed from the pin fitting position Sins so as to be on the small working angle / small lift side, the process returns to step 122.

  If it is determined in step 124 that the control shaft position S has changed so as to be closer to the small working angle / small lift amount side than the pin fitting position Sins, the OCV 84 is deactivated and applied to the pin 74. The hydraulic load is released (step 126). Thereafter, the operation time is reset (step 128). Thereafter, this routine is temporarily terminated.

  As described above, according to the routine shown in FIG. 16, when switching from the single valve variable control to the large working angle / large lift amount side from the pin fitting position of the double valve variable control, at every predetermined operation time, The hydraulic load applied to the pin 74 is maintained so that the pin 74 is not pulled out. Thereby, the surface on which the force is applied to the pin 74 can be changed, and the pin 74 can be rotated in the pin hole 76. Therefore, the occurrence of uneven wear at the pin 74 and the pin hole 76 can be prevented. Furthermore, since it is possible to avoid the concentration of sludge generation locations in the pin hole 76, the pin 74 can be prevented from sticking.

  In the present third embodiment, the ECU 60 executes the processing of steps 120 and 122 to realize the “disconnection prohibiting means” in the third invention.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. FIG. 2 is a perspective view for explaining the configuration of a variable valve operating device 18 in the system shown in FIG. 1. It is a figure for demonstrating the structure of the variable valve mechanism 40 in the variable valve apparatus 18 shown in FIG. FIG. 3 is an exploded perspective view showing a variable valve mechanism 40 and a fixed valve mechanism 70 shown in FIG. 2. FIG. 3 is a schematic diagram showing a configuration of a hydraulic system for operating a pin 74. 3 is a schematic diagram showing a drive mechanism of a control shaft 41. It is a figure which shows an example of a one-valve variable area | region and a both-valve variable area | region. 4 is a diagram for explaining normal control of a control shaft position S. FIG. It is a figure for demonstrating normal control of the control axis position S (command value Sord). It is a figure for demonstrating the smoothing control of the control axis position S (command value Sord) by Embodiment 1 of this invention. 5 is a flowchart showing a routine that is executed by the ECU 60 in the first embodiment of the present invention. It is a figure which shows the relationship between an operation pattern and the engine speed at the time of switching. It is a figure for demonstrating the smoothing control of the command value Sord implemented in Embodiment 2 of this invention. In Embodiment 2 of this invention, it is a flowchart which shows the routine which ECU60 performs. It is a figure which shows the force relationship through the pin 74 of the rocking | swiveling arm 50R and the large lift arm 71. FIG. In Embodiment 3 of this invention, it is a flowchart which shows the routine which ECU60 performs.

Explanation of symbols

1 Internal combustion engine 16 Main cam 17 Large lift cam 41 Control shaft 50L First swing arm 50R Second swing arm 60 ECU
71 Large lift arm 73 Large lift roller 74 pin 76 pin hole 84 OCV
99 Electric motor

Claims (3)

One-valve variable control that fixes the valve opening characteristics of the switching target valve and makes the valve opening characteristics of other valves variable, and the both-valve variable control that makes both the valve opening characteristics of the switching target valve and the other valves variable A variable valve mechanism control device capable of switching between
A swing member provided so as to be swingable according to the position of the control shaft and transmitting the pressing force of the main cam to the valve;
A large lift arm that transmits a pressing force of a large lift cam having a cam height higher than that of the main cam to the switching target valve during one-valve variable control;
A pin for connecting the swinging member and the large lift arm at the time of single valve variable control, and a pin for releasing the connection at the time of variable control of both valves;
Command value calculating means for calculating a command value of the position of the control axis;
Control axis driving means for driving the control axis based on the command value;
When switching from the one-valve variable control to the two-valve variable control, when changing the control shaft position to the larger working angle side than the pin connection position, it is the time required to release the connection by the pin A disconnection time calculating means for calculating the disconnection time;
The control device for a variable valve mechanism, wherein the command value calculation means makes the command value so that a control shaft position does not exceed a pin connection position during the connection release time. The control apparatus for a variable valve mechanism according to claim 1,
The command value calculation means, when switching from the one-valve variable control to the two-valve variable control, makes the change in the command value faster when the engine speed is low than when it is high. Control device for variable valve mechanism. In the control apparatus for a variable valve mechanism according to claim 1 or 2,
When switching from the one-valve variable control to the two-valve variable control, if the control shaft position is changed to the larger operating angle side than the pin connection position, the connection by the pin is released every predetermined operation time. A control apparatus for a variable valve mechanism, further comprising a disengagement prohibiting means for prohibiting.

Images