JP5984460B2 - Variable valve mechanism for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve mechanism for an internal combustion engine.

  In a variable valve mechanism that can change the lift amount and open / close timing of the intake valve by connecting or releasing the rocker arms that are coaxially supported and adjacent to each other by the movement of the connection pin, an electromagnetic as an actuator that moves the connection pin An example of using a solenoid is in a prior application related to the same applicant (see Patent Document 1).

JP 2012-036877 A

  In the variable valve mechanism disclosed in Patent Document 1, a connection pin that connects adjacent rocker arms is biased by a spring from one side and pushed by a movable iron core of an electromagnetic solenoid from the other side.

When the electromagnetic solenoid is excited, the movable iron core protrudes and moves the connecting pin against the spring to connect the two rocker arms. When the electromagnetic solenoid is demagnetized, the connecting pin is pushed back by the spring and the connection is released. .
In patent document 1, the control beyond the electromagnetic solenoid being controlled as described above is not disclosed.

When both the rocker arms are connected, the connecting pin must be moved and maintained against the spring, so that a voltage is always applied to the electromagnetic solenoid to increase power consumption, leading to an increase in battery size.
In addition, since the pressing force is small unlike the hydraulic pressure, the power consumption is further increased in order to keep the connected state.

  Further, when the electromagnetic solenoid is demagnetized and the connection between the two rocker arms is released, the coupling pin and the movable iron core are pushed back by the biasing force of the spring due to the demagnetization of the electromagnetic solenoid. By moving due to inertia, a hitting sound may be generated in contact with the stopper equivalent part in the electromagnetic solenoid.

  The present invention has been made in view of this point, and the object of the present invention is to control the duty of the electromagnetic solenoid that moves the connecting pin to reduce the power consumption of the electromagnetic solenoid and to prevent the temperature of the electromagnetic solenoid from rising. In addition, a variable valve mechanism for an internal combustion engine that prevents the occurrence of sound is provided.

In order to achieve the above object, the invention according to claim 1
The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70) controls the duty of the electromagnetic solenoid (60) to drive the movable core member (61, 62),
The electromagnetic solenoid (60) is demagnetized in a connection release state in which the connection pin (56) is fitted into the other hole (52h) and the rocker arms (51, 52) can swing independently of each other. From the time when the electromagnetic solenoid (60) is duty controlled with a movement start duty ratio (a) for starting the movement of the connecting pin (56) against the biasing force of the spring (54), the movement start Change the duty ratio (b) smaller than the duty ratio (a) and repeat the duty control of the electromagnetic solenoid (60) multiple times, and adjust the moving speed of the movable core member (61, 62) The connecting pin (56) is pushed into the one hole (51h), and the both rocker arms (51, 52) are connected across both the holes (51h, 52h). It is a variable valve mechanism.

The invention according to claim 2
The variable valve mechanism for an internal combustion engine according to claim 1,
After a lapse of a predetermined time (T) sufficient for the connection pins (56) to complete the connection of the rocker arms (51, 52), the electromagnetic solenoid (60) is fixed to the connection maintenance duty ratio (b). ) Is duty controlled .

The invention described in claim 3
The variable valve mechanism for an internal combustion engine according to claim 1 or 2 ,
Oil temperature detection means (27) for detecting the temperature of the lubricating oil of the internal combustion engine (10),
The control means (70)
Predetermined oil temperature range is set in advance between oil temperature approximately 60 ℃ and 80 ℃,
When the oil temperature detected by the oil temperature detecting means (27) is outside a predetermined oil temperature range, the standard movement start is started to move the connecting pin (56) against the urging force of the spring (54). Duty-controlling the electromagnetic solenoid (60) by duty-controlling the electromagnetic solenoid (60) by duty-controlling the electromagnetic solenoid (60) with a duty ratio (a) and then changing the connection-maintaining duty ratio (b) to be smaller than the standard movement start duty ratio (a) Repeat several times,
When the oil temperature detected by the oil temperature detecting means (27) is within a predetermined oil temperature range, the special movement start duty ratio is smaller than the standard movement start duty ratio (a) and larger than the connection maintenance duty ratio (b). The movement control of the connection pin (56) in (a ′) and then the change to the connection maintenance duty ratio (b) and the duty control of the electromagnetic solenoid (60) are repeated a plurality of times.

The invention according to claim 4
The variable valve mechanism for an internal combustion engine according to claim 3 ,
The standard movement start duty ratio (a) and the special movement start duty ratio (a ′) are determined from a map correlated with an oil temperature value.

The invention according to claim 5
The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70)
Duty-controlling the electromagnetic solenoid (60) to drive the movable core member (61, 62),
The hole of both the coupling pin (56) (51h, 52h) stepwise the duty ratio from the connection maintaining the duty ratio to maintain a state where the concatenation of the two rocker arms (51, 52) with span (b) Is controlled to adjust the moving speed of the movable core member (61, 62) to stop the movable core member (61, 62) and release the connection.

The invention described in claim 6
The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70)
Duty-controlling the electromagnetic solenoid (60) to drive the movable core member (61, 62),
The hole of both the coupling pin (56) (51h, 52h) and 0 the duty ratio from the connection maintaining duty ratio (b) to maintain a state where the concatenation of the two rocker arms (51, 52) with span After that, at a predetermined timing, the brake duty ratio (b ′) which is smaller than the connection maintaining duty ratio (b) and larger than 0 is controlled to suppress the moving speed of the movable core member (61, 62), and the movable core member (61 , 62) is stopped and the connection is released.

The invention described in claim 7
The variable valve mechanism for an internal combustion engine according to claim 6 ,
The brake duty ratio (b ′) is determined from a map correlated with the oil temperature value.

The invention described in claim 8
The variable valve mechanism for an internal combustion engine according to claim 6 ,
The position of the movable core member (61, 62) is detected by a position sensor, and the brake duty ratio (b ′) is controlled at a predetermined position to suppress the moving speed of the movable core member (61, 62). The movable core member (61, 62) is stopped and the connection is released.

According to the variable valve mechanism of the internal combustion engine according to claim 1, since the control means (70) controls the duty of the electromagnetic solenoid (60) to drive the movable iron core member (61, 62), Also, by controlling the duty, the power consumption of the electromagnetic solenoid (60) can be kept low.
In addition, it is possible to prevent the movable iron core member (61, 62) from coming into contact with the stopper equivalent portion and generating a hitting sound by suppressing the moving speed of the movable iron core member (61, 62) before stopping.

  Duty control of the electromagnetic solenoid (60) with the movement start duty ratio (a) that starts the movement against the biasing force of the spring (54) after the electromagnetic solenoid (60) is demagnetized After that, since the electromagnetic solenoid (60) is duty controlled by changing the connection maintenance duty ratio (b) to be smaller than the movement start duty ratio (a), the movement start duty ratio (a ) With a large pressing force, the connecting pin (56) can be pushed into one hole (51h) and connected across both holes (51h, 52h), and then the movement start duty ratio (a) When the connection state can be maintained by changing to a smaller connection maintenance duty ratio (b), the power consumption of the electromagnetic solenoid can be kept low, and the movement speed of the connection pin (56) is adjusted to stop. Push the spring (54) to the end to generate vibration. So that things can be avoided.

Duty control of the electromagnetic solenoid (60) with the movement start duty ratio (a), then change to the connection maintenance duty ratio (b) and duty control of the electromagnetic solenoid (60) multiple times, so that the connection pin ( Even if 56) comes off from one of the holes (51h), the duty is repeatedly controlled at the duty ratio (a) for repeated movement, and the connection pin (56) is reliably inserted into the hole (51h). The connected state can be achieved, and the power consumption of the electromagnetic solenoid can be reduced by the small connection maintaining duty ratio (b).

According to the variable valve mechanism of the internal combustion engine according to claim 3 , when the engine temperature (oil temperature) of the internal combustion engine rises and the temperature of the lubricating oil exceeds about 60 ° C., the connecting pin (56) slides. When the viscosity of the lubricating oil to be lubricated is low and the temperature is less than about 80 ° C, the coil resistance of the electromagnetic solenoid is small and the coil current easily flows, and the projecting output of the movable core member (61, 62) is increased. When the electromagnetic solenoid is excited in the oil temperature range up to ℃, the moving speed of the connecting pin (56) tends to be fast, and it does not stop smoothly and the possibility of vibrations increases. A predetermined oil temperature range is set in advance up to 80 ° C., and duty control of the electromagnetic solenoid (60) is changed within and outside the predetermined oil temperature range.

  That is, when the oil temperature is outside the predetermined oil temperature range, after the duty control of the electromagnetic solenoid (60) with the standard movement start duty ratio (a), the connection maintenance duty ratio (b) smaller than the movement start duty ratio (a) ) And the duty control of the electromagnetic solenoid (60) is repeated multiple times to increase the movement speed due to a large pressing force at the standard movement start duty ratio (a) at the start of movement of the connecting pin (56). By repeatedly changing the pressure to a smaller pressing force of the connection maintaining duty ratio (b), the moving speed is adjusted and the connecting pin (56) is straddled across both holes (51h, 52h) and stopped. It is possible to avoid pushing the spring (54) to the end to generate vibration.

  When the oil temperature is within the specified oil temperature range, the moving speed of the connecting pin (56) tends to increase, so the special moving start duty is smaller than the standard moving start duty ratio (a) and larger than the connected maintenance duty ratio (b). Multiple duty control of the electromagnetic solenoid (60) by changing the duty ratio (b) to a smaller than the special movement start duty ratio (a ') after duty control of the electromagnetic solenoid (60) with the ratio (a') Repeatedly changing the pressing force smaller than the standard of the special movement start duty ratio (a ′) at the start of movement of the connecting pin (56) to a smaller pressing force of the connection maintaining duty ratio (b) Thus, the connecting pin (56) can be stopped across both the hole portions (51h, 52h) by adjusting the moving speed suitable for the oil temperature within the predetermined oil temperature range.

Even when the oil temperature is within or outside the predetermined oil temperature range, the connection is finally maintained with a small connection maintenance duty ratio (b), and the power consumption of the electromagnetic solenoid can be reduced.
Even if the connecting pin (56) does not enter the first time and is not connected, the duty is controlled repeatedly with the standard movement start duty ratio (a) or the special movement start duty ratio (a ′), and the connection pin (56) is It can be surely brought into a connected state trying to be inserted into the hole (51h).

According to the variable valve mechanism for an internal combustion engine according to claim 4 , the standard movement start duty ratio (a) and the special movement start duty ratio (a ') are determined from a map correlated with the oil temperature value. The generation of sound is suppressed by appropriately changing the speed of the movable core member (61, 62) according to the engine temperature state (that is, the resistance change of the electromagnetic solenoid or the viscosity change of the lubricating oil).

According to the variable valve mechanism of the internal combustion engine according to claim 5 , the control means (70) includes both the rocker arms (51, 52) with the connecting pin (56) straddling both the hole portions (51h, 52h). ) To maintain the connected state, the duty ratio is gradually reduced from the connection maintaining duty ratio (b) to adjust the moving speed of the movable core member (61, 62), and the movable core member (61, 62) Since the connection is released and the connection is released, the moving speed of the movable core member (61, 62) immediately before stopping can be easily kept low, and the occurrence of hitting sound can be prevented.

According to the variable valve mechanism for an internal combustion engine according to claim 6 , the control means (70) includes both the rocker arms (51, 52) with the connecting pin (56) straddling both the holes (51h, 52h). ) Is maintained from the connection maintaining duty ratio (b), the duty ratio is set to 0, and then the brake duty ratio (b ′) smaller than the connection maintaining duty ratio (b) and larger than 0 is controlled at a predetermined timing. Since the movable core member (61, 62) is stopped by suppressing the moving speed of the movable core member (61, 62) and the connection is released, the movable core member (61, 62) is controlled by duty control based on the brake duty ratio (b ′). The movement speed of 62) is suppressed, and the movement speed can be easily kept low immediately before the stop, and the occurrence of a hitting sound can be prevented.

According to the variable valve mechanism for an internal combustion engine according to claim 7 , the brake duty ratio (b ′) is determined from a map that correlates with the oil temperature value. The movable iron core members (61, 62) are appropriately braked in accordance with the resistance change or the viscosity change of the lubricating oil to suppress the occurrence of hitting sound.

According to the variable valve mechanism for an internal combustion engine according to claim 8, the position of the movable iron core member (61, 62) is detected by a position sensor, and is controlled by the brake duty ratio (b ') at a predetermined position. The moving core member (61, 62) is stopped and the connection is released by suppressing the moving speed of the iron core member (61, 62). Suppress.

1 is a partial side view of a motorcycle equipped with an internal combustion engine according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the same internal combustion engine. It is a top view of the cylinder head which shows the valve mechanism of the same internal combustion engine. It is the IV-IV sectional view taken on the line of FIG. It is a flowchart of the main control routine of an electromagnetic solenoid. It is a flowchart of a connection release control routine. It is a flowchart of another connection cancellation | release control routine. It is a flowchart of a connection control routine. It is a figure which shows the change of the voltage duty control of the electromagnetic solenoid in connection cancellation | release control. It is a figure which shows the change of the voltage duty control of the electromagnetic solenoid in connection control.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 shows a partial side view of a motorcycle 1 equipped with an internal combustion engine 10 according to this embodiment.
The motorcycle 1 is attached to a pair of left and right main frames 3, 3 that extend backward from the head pipe 2 and bend obliquely downward in the middle, and down frames 4, 4 that extend obliquely rearward and downward from the head pipe 2. The internal combustion engine 10 is suspended via

  The internal combustion engine 10 is an SOHC type two-valve air-cooled single-cylinder four-stroke internal combustion engine 10. A cylinder block 12, a cylinder head 13, and a cylinder head cover 14 are sequentially stacked on a crankcase 11 that supports a crankshaft 25. Stands in a leaning posture.

An intake pipe 15 extends from the rear surface of the cylinder head 13 via a connecting pipe 15 c and is connected to an air cleaner 17 via a throttle body 16.
A fuel injection valve 20 is attached to the intake pipe 15 (see FIG. 2).
The exhaust pipe 18 extending from the front surface of the cylinder head 13 is bent downward and extends rearward from the front surface of the crankcase 11 along the lower surface and is connected to the muffler 19.

  Referring to FIG. 2, a piston 20 is slidably fitted in a cylinder bore 12b of a cylinder block 12 of the internal combustion engine 10, and the piston 21 is connected to a crankshaft 25 by a connecting rod 22 to constitute a crank mechanism. Yes.

A combustion chamber 30 is formed in the cylinder head 13 so as to face the piston 20 in correspondence with the cylinder bore 12b. An intake port 31 extends rearward from the combustion chamber 30, and an exhaust port 32 extends forward from the combustion chamber 30. The intake pipe 15 is connected to the intake port 31, and the exhaust pipe 18 is connected to the exhaust port 32.
A spark plug 26 is attached to the ceiling wall of the combustion chamber 30 with its tip facing the combustion chamber 30 (see FIG. 4).

  As shown in FIG. 2, the intake valve 33 and the exhaust valve 34 slidably supported by the valve guide integrally fitted to the cylinder head 13 are respectively moved upward by the intake valve spring 35 and the exhaust valve spring 36. The intake valve opening of the intake port 31 facing the combustion chamber 30 and the exhaust valve opening of the exhaust port 32 are closed, and the crankshaft 25 is rotated by a variable valve mechanism 25 configured on the cylinder head 13. In synchronization, the intake valve 33 and the exhaust valve 34 are pressed from above and opened.

  The variable valve mechanism 40 is formed with cam bearing walls 13L and 13R projecting upward on the upper surface of the inner cam chamber bottom wall 13b surrounded by the outer peripheral wall 13a of the cylinder head 13 so as to protrude left and right. A cam shaft 41 is rotatably supported on the walls 13L and 13R via bearings 42 and 43 in the left-right direction.

The cam shaft 41 protrudes leftward through the left cam bearing wall 13L, and a chain sprocket 44 is attached to the protruding portion.
A chain 45 is stretched over the chain sprocket 44 and a chain sprocket (not shown) fitted to the crankshaft 25, and the camshaft 41 rotates at a rotational speed that is half the rotational speed of the crankshaft 25. .

  A chain opening 13h is formed on the left side of the left cam bearing wall 13L through the cam chamber bottom wall 13b, and a chain 45 wound around the chain sprocket 44 extends downward through the chain opening 13h. The chain sprocket is wound around the chain sprocket fitted to the crankshaft 25 in the crankcase 11 through the chain chamber 12h.

  As shown in FIG. 3, an oil reservoir recess 13d that is recessed downward is formed in the cam chamber bottom wall 13b of the cylinder head 13 at the rear of the chain opening 13h, and is formed on the rear side wall of the outer peripheral wall 13a of the cylinder head 13. The detection part 27s at the tip of the oil temperature sensor 27 mounted from the outside protrudes into the oil reservoir recess 13d, and the oil temperature sensor 27 can detect the temperature of the lubricating oil collected in the oil reservoir recess 13d.

  Between the left and right bearing walls 13a and 13b, an intake rocker arm shaft 47 is installed obliquely rearward above the cam shaft 41, and an exhaust rocker arm shaft 48 is constructed obliquely forward above the cam shaft 41. The first intake rocker arm 51 and the second intake rocker arm 52 are pivotally supported adjacent to each other, and the exhaust rocker arm 53 is pivotally supported on the exhaust rocker arm shaft 48.

In the first intake rocker arm 51, the roller 51r at the end on the camshaft 41 side is in contact with the first intake cam lobe 41i of the camshaft 41, and the adjustment screw 51s at the other end is in contact with the upper end of the valve stem of the intake valve 33. .
In the second intake rocker arm 52, the roller 52r at the end on the camshaft 41 side is in contact with the second intake cam lobe 41ii of the camshaft 41, and the other end 52a is received in a receiving recess 13bd formed in the cam chamber bottom wall 13b. In contact with the upper end of the lifter 38 urged by the coil spring 37 (see FIG. 2).

The first intake cam lobe 41i and the second intake cam lobe 41ii have different profiles, and the second intake cam lobe 41ii for the high load operation region has the same diameter base as the first intake cam lobe 41i for the low load operation region. The cam nose protruding in the same direction from the circle is high, and the cam operating angle is large.
On the other hand, in the exhaust rocker arm 53, the roller 53r at the end on the camshaft 41 side is in contact with the exhaust cam lobe 41e of the camshaft 41, and the adjustment screw 53s at the other end is in contact with the upper end of the valve stem of the exhaust valve 34.

  The first intake rocker arm 51 and the second intake rocker arm 52 both have projecting portions 51a and 52a projecting upward, and the projecting portions 51a and 52a have recesses with circular holes of the same diameter opened on the adjacent surfaces. 51h and 52h are formed respectively.

A bottomed cylindrical plunger 55 is inserted into a recess 51h of the left first intake rocker arm 51 with a spring 54 interposed between them, and the plunger 55 causes the plunger 55 to protrude rightward from the second intake rocker arm 52 by the spring 54. It is biased towards 52a.
The concave portion 52h of the right second intake rocker arm 52 has a circular hole in the bottom wall corresponding to the right side wall, and a connecting pin 56 is inserted into the concave portion 52h so that the extending rod extends to the right of the connecting pin 56. The portion 56b protrudes through the circular hole in the bottom wall of the recess 52h.

  As shown in FIGS. 3 and 4, when the connecting pin 56 is completely inserted into the recess 52h by being urged by the spring 54 and pushed by the plunger 55, the left end surface of the connecting pin 56 is in the first and second positions. The protrusions 51a, 52a of the intake rocker arms 51, 52 are flush with the adjacent surfaces of each other. At this time, the connecting pin 56 is only inserted into the recess 52h, so the first intake rocker arm 51 and the second intake rocker arm 52 are inserted. Can swing independently of each other.

When both the concave portions 51h and 52h are coaxial while the first intake rocker arm 51 and the second intake rocker arm 52 swing independently, as shown in FIGS. When the connecting pin 56 is only inserted into the recess 52h and the left end surface thereof is flush with the adjacent surfaces of the protrusions 51a and 52a, both the recesses 51h and 52h are off the same axis. Also, the left end surface of the connecting pin 56 is in contact with the adjacent surface of the protrusion 51a of the first intake rocker arm 51 and is maintained on the same surface as the adjacent surface.
The plunger 55 is urged by the spring 54 so as to be in contact with the adjacent surface of the protruding portion 52a of the second intake rocker arm 52 and to be maintained on the same surface as the adjacent surface.

The cylinder head 13 and the cylinder head cover 14 are joined together by combining the outer peripheral walls 13a, 14a, and an electromagnetic solenoid 60 is attached from the outside to the height position of the mating surface of the right side wall of the outer peripheral walls 13a, 14a. Yes.
A push rod 61, which is a movable iron core of the electromagnetic solenoid 60, protrudes leftward through the mating surface of the right side wall of the outer peripheral walls 13a, 14a and protrudes into the cam chamber. A pressing body 62 is attached.

  The push rod 61 protrudes toward the projecting portion 52a of the second intake rocker arm 52, and the end of the second intake rocker arm 52 is extended to the end surface of the distal end enlarged portion 62b. The right end of the extending rod portion 56b of the connecting pin 56 protruding from the protruding portion 52a is in contact.

  In a state where the electromagnetic solenoid 60 is demagnetized, as shown by solid lines in FIGS. 3 and 4, the spring 54 is biased so that the connecting pin 56 is inserted only into the recess 52h, and the first intake rocker arm 51 and the second intake air are inserted. The rocker arms 52 swing independently of each other.

  When the electromagnetic solenoid 60 is excited, a leftward projecting output acts on the push rod 61 and pushes the connecting pin 56 to the left via the pressing body 62, so that the first and second intake rocker arms 51 and 52 protrude. When the recesses 51h and 52h of the portions 51a and 52a are coaxial, the connecting pin 56 is inserted into the recess 51h while pushing the plunger 55 into the recess 51h of the first intake rocker arm 51 against the biasing force of the spring 54. The first intake rocker arm 51 and the second intake rocker arm 52 are connected to each other by the connecting pin 56 so as to extend over both the concave portions 51h and 52h (see the two-dot chain lines in FIGS. 3 and 4). Move.

  When the internal combustion engine is in a low load operation state, the electromagnetic solenoid 60 is demagnetized and the connecting pin 56 is only inserted into the recess 52h, and the first intake rocker arm 51 and the second intake rocker arm 52 swing independently of each other. The first intake rocker arm 51 is swung by the first intake cam lobe 41i for the low load operation region where the cam operating angle is small and the cam nose is low, and the intake valve is driven by the swing of the first intake rocker arm 51 based on the first intake cam lobe 41i. 33 is opened and closed with a small lift amount in a short valve opening time of low load operation.

  When the internal combustion engine enters a high load operation state, the electromagnetic solenoid 60 is excited, the push rod 61 pushes the connecting pin 56 and the connecting pin 56 is inserted into the recess 51h against the urging force of the spring 54, and both the recesses 51h, Since the first intake rocker arm 51 and the second intake rocker arm 52 are integrally connected over 52h, the second intake cam lobe 41ii for the high load operation region having a large cam operating angle and a high cam nose is swung. The first intake rocker arm 51 swings integrally with the intake rocker arm 52, and the first intake rocker arm 51 swings based on the second intake cam lobe 41ii, so that the intake valve 33 has a large lift amount with a long valve opening time during high load operation. Open / close drive is performed.

The electromagnetic solenoid 60 is controlled by an ECU 70 which is an engine control computer (see FIG. 3), and controls the movement of the push rod 61 when connected by the connecting pin 56 and when the connection is released. The applied voltage of the electromagnetic solenoid 60 is duty-controlled so that no occurrence occurs.
Hereinafter, the control of the electromagnetic solenoid 60 will be described based on the control flowcharts shown in FIGS. 5 to 8 and the duty control voltage of the electromagnetic solenoid 60 shown in FIGS.

  The ECU 70 determines the operating state of the internal combustion engine 10 from the engine speed, the throttle opening degree, the vehicle speed, and the like, and the engine temperature corresponding to the temperature of the lubricating oil detected by the oil temperature sensor 27. The connection control of the electromagnetic solenoid 60 is performed when shifting to the high load state, and the connection release control of the electromagnetic solenoid 60 is performed when shifting from the high load state to the low load state.

Referring to the flowchart of FIG. 5 which is the main control routine of the electromagnetic solenoid 60, it is first determined in step 1 whether or not the internal combustion engine 10 is in a low load state. It is determined whether or not the connection flag F is “1”. If it is “1”, the process proceeds to step 3 to start timing and enters the connection release control routine of step 4, but if it is “0” instead of “1”. Step 3 is skipped and the connection release control routine of step 4 is entered.
Once the connection release control routine is entered, the connection flag F is set to “0” in step 5.

  That is, when the transition from the high load state to the low load state is made, the connection flag F is “1”, the timing of step 3 is started and the connection release control routine is entered, and thereafter the connection flag F is “0”. Thus, step 3 is skipped, and the connection release control routine is continued while the timing is continued.

If it is determined in step 1 that the load is not low, that is, the load is high, the process jumps to step 6 to determine whether or not the connection flag F is “0”. The time measurement is started and the connection control routine of step 8 is entered, but if it is “1” instead of “0”, step 7 is skipped and the connection control routine of step 8 is entered.
Once in the connection control routine, the connection flag F is set to “1” in step 9.

  That is, when shifting from the low load state to the high load state, the connection flag F is “0”, the time measurement in step 7 is started and the connection control routine is entered, and thereafter the connection flag F is set to “1”. Thus, step 7 is skipped, and the connection control routine is continued while the timing is continued.

Here, the electromagnetic solenoid 60 is subjected to PWM duty control, and when the connection is released, the duty ratio Rd is 0% in the demagnetized state.
The duty ratio Rd for maintaining the connected state where the connecting pin 56 is inserted into the recess 51h against the urging force of the spring 54 and straddles both the recesses 51h, 52h is set to the connection maintaining duty ratio b% (for example, 70%). %).

An example of the connection release control routine of step 4 is shown in the flowchart of FIG. 6 and voltage duty control is shown in FIG.
When shifting from the high load state to the low load state, the connection release control routine is entered, but immediately before the connection release control routine is entered, the duty ratio Rd is in the connected state at b%.

  When timekeeping is started (step 3) and the connection release control routine is entered (step 4), the time t has reached t3 in step 11 of FIG. 6, or the time t is t2 (<t3) in step 12 Since the initial time t has not reached the time t3 as well as the time t2, the process proceeds to step 13 where the duty ratio Rd is set to c% (<b%, for example, 50%), and the actual voltage The electromagnetic solenoid 60 is duty controlled with a duty ratio Rd of c%.

When the time t reaches the time point t2, the process proceeds from step 12 to step 14, the duty ratio Rd is set to d% (<c%, for example, 30%), and the duty ratio Rd is set to d% by further reducing the actual voltage. The duty of the electromagnetic solenoid 60 is controlled with this.
Thereafter, when the time t reaches the time point t3, the process proceeds from step 11 to step 15, where the duty ratio Rd is set to 0 and the electromagnetic solenoid 60 is demagnetized.

FIG. 9 (1) shows the change in voltage duty control of the electromagnetic solenoid 60 in the above connection release control.
In a high load state, the electromagnetic solenoid 60 is duty-controlled with the connection maintaining duty ratio b%, and the connection pin 56 is inserted into the recess 51h and straddles both the recesses 51h, 52h, and the first intake rocker arm 51 and the second intake rocker arm. At the time t1 when the internal combustion engine 10 shifts to a low load state (corresponding to the time t = 0 when the time measurement is started) from the state in which the engine 52 is integrally connected, the duty ratio Rd is reduced to c% and the time measurement time When t reaches the time t2, the duty ratio Rd is further reduced to d%, and when the time t reaches the time t3, the duty ratio Rd is set to 0%. Therefore, the actual voltage indicated by the broken line is stepped from the connection maintaining voltage. It drops to 0.

Accordingly, since the pressing force for inserting the connecting pin 56 into the recess 51h is reduced stepwise, the connecting pin 56 and the push rod 61 are moved at a reduced speed by the biasing force of the spring 54, and the connecting pin 56 is moved into the recess 51h. Disconnect from and disconnect.
Since the connecting pin 56 completely comes out of the recess 51h before and after the time t3, the moving speed immediately before the push rod 61 stops can be easily kept low, and the occurrence of hitting sound can be prevented.

Another example of the connection release control is shown in the flowchart of FIG.
When the internal combustion engine 10 in the connected state and in the high load state shifts to the low load state, time measurement is started (step 3), and the time t has reached t3 in step 21, or the time t has been t2 in step 22. (<T3) It is determined whether the time point has been reached. Since the initial time t has not reached the time point t2 as well as the time point t3, the process proceeds to step 23, the duty ratio Rd is set to 0%, and the electromagnetic solenoid 60 is demagnetized. Thereafter, when the time t reaches a time point t2 that is substantially before the connecting pin 56 comes out of the recess 51h, the routine proceeds from step 22 to step 24, where the duty ratio Rd is excited with the brake duty ratio b '% (for example, 60%). Then, the movement of the connecting pin 56 and the push rod 61 is braked. Then, when the time t reaches the time point t3, the process proceeds from step 11 to step 15, the duty ratio Rd is set to 0, and the electromagnetic The isoprenoid 60 and demagnetized state.

FIG. 9B shows the change in voltage duty control of the electromagnetic solenoid 60 in the above connection release control.
The internal combustion engine from when the connection pin 56 is inserted into the recess 51h in a high load state and the first intake rocker arm 51 and the second intake rocker arm 52 are integrally connected across the recesses 51h and 52h. At time t1 when 10 shifts to a low load state (corresponding to time t = 0 when timing is started), the electromagnetic solenoid 60 is demagnetized by setting the duty ratio Rd to 0. Therefore, the connecting pin 56 and the push rod are urged by the urging force of the spring 54. 61 moves vigorously, but at time t2, the electromagnetic solenoid 60 is excited with a brake duty ratio b '%, so that the movement of the connecting pin 56 and the push rod 61 is braked, and before and after time t3 when the brake control is finished. By setting the connecting pin 56 so as to come out of the recess 51h, the moving speed can be easily kept low immediately before the connecting pin 56 and the push rod 61 are stopped. It is possible to prevent the occurrence of sound.

  The time t2 when the excitation is started at the brake duty ratio b ′% and the brake duty ratio b ′% are determined in advance as the appropriate time t2 and the brake duty ratio b ′%, but the optimum time t2 corresponding to the oil temperature. In addition, the brake duty ratio b ′% is obtained in advance and made into a map, so that the brake can be controlled with the optimal brake duty ratio b ′% at the optimal time t2 corresponding to the oil temperature, and the push rod 61 moves immediately before stopping. The speed can be further reduced, and the occurrence of a hitting sound can be prevented.

  Further, at the time t2 when the excitation is started with the brake duty ratio b ′% and the brake is applied, the position of the push rod 61 that is returned by the biasing force of the spring 54 is detected by the position sensor, and the push rod 61 is positioned at the optimum position for applying the brake. The return time may be detected, and the electromagnetic solenoid 60 may be excited with the brake duty ratio b ′% at this time point t2.

  The correlation between the brake duty ratio (b ′) and the oil temperature is obtained in advance and mapped, so that the temperature state of the internal combustion engine (that is, the resistance change of the electromagnetic solenoid or the viscosity change of the lubricating oil due to the temperature) from the map ), The movable iron core members (61, 62) can be appropriately braked to suppress the occurrence of hitting sound.

Next, an example of the connection control routine is shown in the flowchart of FIG. 8, and voltage duty control is shown in FIG.
When shifting from the low load state to the high load state, the connection control routine is entered. Immediately before entering the connection control routine, the duty ratio Rd is 0% and the connection is released.

  When timekeeping is started (step 7) and the connection control routine is entered (step 8), the lubricant temperature (oil temperature) Yt detected by the oil temperature sensor 27 is preset in step 31 of FIG. It is determined whether or not it is within the oil temperature range.

  If the oil temperature exceeds about 60 ° C, the viscosity of the lubricating oil that lubricates the sliding of the connecting pin 56 will be low, and if the oil temperature is less than about 80 ° C, the coil resistance of the electromagnetic solenoid will be small and the coil current will flow easily. Even at the applied voltage, the projecting output of the movable iron core members (61, 62) increases, so the moving speed of the connecting pin (56) increases when the electromagnetic solenoid is excited in the oil temperature range of approximately 60 ° C to 80 ° C. The oil temperature is likely to be high and the oil temperature is generally between 60 ° C and 80 ° C. The predetermined oil temperature range where the moving speed is likely to increase is set in advance, and the electromagnetic temperature is set within and outside the predetermined oil temperature range. The duty control of the solenoid (60) is changed.

In the present embodiment, the predetermined oil temperature range is set to 60 ° C. <Yt <80 ° C.
This predetermined oil temperature range is a temperature range in which vibration generated in the cylinder head is larger than in other regions.
In step 31, it is determined whether or not the oil temperature Yt is within a predetermined oil temperature range (60 ° C. <Yt <80 ° C.), and it is determined that the oil temperature is outside the predetermined oil temperature range (Yt ≦ 60 ° C., 80 ° C. ≦ Yt). Then, the process proceeds to step 32, where it is determined whether or not the time t has reached a predetermined time T sufficient to complete the connection. Since the predetermined time T has not been initially reached, the process proceeds to step 33 and the subtraction count value i is reached. Is determined to be 0. If it is not 0, the routine proceeds to step 34, where the duty ratio Rd is set to the standard movement start duty ratio a% (for example, 90%) at the start of movement of the connection pin 56, and the connection maintaining duty ratio The electromagnetic solenoid 60 starts duty control with a duty ratio a% larger than b% and is excited, and the push rod 61 presses the connection pin 56 in the connection release position.
In step 35, 1 is subtracted from the subtraction count value i.

  The subtraction count value i is initially set to the initial value I (steps 39 and 41), and steps 31, 32, 33, 34, and 35 are repeated, and the duty is controlled at the standard movement start duty ratio a%. When the subtraction count value i becomes 0, the routine jumps from step 33 to step 36, where it is determined whether another subtraction count value j is 0 or not.

If the subtraction count value j is not 0, the routine proceeds to step 37, where the duty ratio Rd is set to the connection maintaining duty ratio b%, and duty control is performed, and at the next step 38, the subtraction count value j is decremented by 1.
The subtraction count value j is initially set to the initial value J (steps 39 and 41), and steps 31, 32, 33, 36, 37, and 38 are repeated, and the duty is controlled at the connection maintaining duty ratio b%. When the subtraction count value j becomes zero, the process jumps from step 36 to step 39, and the subtraction count values i and j are set to the initial values I and J, respectively.

  Here, if the measured time t has not yet reached the predetermined time T, the routine proceeds from step 32 to step 33, where the duty control at the standard movement start duty ratio a% and the duty control at the connection maintaining duty ratio b% are executed. The measurement time t is repeated a plurality of times until the predetermined time T is reached.

  When the time t reaches the predetermined time T, the routine jumps from step 32 to step 40, the duty ratio Rd is fixed to the duty control as the connection maintaining duty ratio b%, and the subtraction count values i, j are set at the next step 41. Are surely set to initial values I and J, respectively.

A change in voltage duty control of the electromagnetic solenoid 60 in the above connection control is shown in FIG.
At the time t1 when the internal combustion engine 10 shifts to the high load state from the time when the electromagnetic solenoid 60 is demagnetized at a duty ratio of 0% in the low load state and the connection pin 56 is disconnected from the recess 51h (at the time when timing is started) t) (corresponding to t = 0), excitation is started by controlling the voltage of the electromagnetic solenoid 60 with the duty ratio Rd being the standard movement start duty ratio a%, and the push rod 61 applies a large pressing force to the connecting pin 56 and subtracts it. At time t2 when the count value i becomes 0, the duty ratio Rd is lowered to the connection maintaining duty ratio b%. At time t3 when the subtraction count value j becomes 0, the duty ratio Rd is increased again to the standard movement start duty ratio a%. Since the duty control of the standard movement start duty ratio a% and the connection maintaining duty ratio b% is repeated until the predetermined time T, the actual voltage is as shown by a broken line in FIG. Repeating the coupling sustain voltage quasi movement starting voltage, is fixed to the connecting sustain voltage for a predetermined time T.

Therefore, by repeatedly changing the increase in the movement speed due to the large pressing force with the standard movement start duty ratio a% at the start of the movement of the connecting pin 56 to the smaller pressing force with the connection maintaining duty ratio b%, the movement speed is reduced. It is possible to adjust and stop the connecting pin 56 so as to straddle both the concave portions 51h and 52h, and it is possible to avoid pushing the spring 54 to the end to generate vibration.
Further, since the duty is controlled with the standard movement start duty ratio a% and the coupling pin 56 is inserted and connected to the recess 51h and the duty is controlled with the connection maintenance duty ratio b% to maintain the connection, the power consumption of the electromagnetic solenoid 60 Can be reduced.

On the other hand, if it is determined in step 31 that the oil temperature Yt is within the predetermined oil temperature range (60 ° C. <Yt <80 ° C.), the routine proceeds to step 42.
The steps from step 42 to step 51 correspond to the steps from step 32 to step 41, respectively, and the duty ratio Rd set in step 44 is smaller than the standard movement start duty ratio a and the link maintenance duty ratio. Other steps are the same except that the special movement start duty ratio a ′ (for example, 80%) is larger than b.

When the oil temperature Yt is within the predetermined oil temperature range (60 ° C. <Yt <80 ° C.), the moving speed of the connecting pin 56 is likely to increase. Therefore, referring to FIG. The connection maintaining duty ratio smaller than the special movement start duty ratio a ′% after exciting the electromagnetic solenoid 60 with the special movement start duty ratio a ′% smaller than a% and larger than the connection maintenance duty ratio b% to control the movement of the connection pin 56. By driving the electromagnetic solenoid 60 by repeating the control to change to b a plurality of times, from the pressing force smaller than the standard of the special movement start duty ratio a ′% at the start of movement of the connection pin 56, the connection maintenance duty ratio b% By repeating the change to a small pressing force, the moving speed suitable for the oil temperature within the predetermined oil temperature range (60 ° C <Yt <80 ° C) is adjusted, and the connecting pin 56 is straddled across both recesses 51h, 52h. Let me stop Rukoto can, be such as to generate sound by pushing the spring 54 to the end can be avoided.
Further, since the duty is controlled with the special movement start duty ratio a ′% and the connection pin 56 is inserted into the recess 51h to be connected and the duty is controlled with the connection maintenance duty ratio b% to maintain the connection. Electric power can be reduced.

  Even when the oil temperature Yt is within or outside the predetermined oil temperature range, even if the connecting pin 56 comes out of the one recess 51h, the standard movement start duty ratio a% or the special movement start is repeated. Since the duty is controlled at the duty ratio a ′% and the connection pin 56 is to be inserted into the recess 51h, the connection state can be reliably established.

  In the present embodiment, the predetermined oil temperature range is set as 60 ° C. <Yt <80 ° C., and this range is a good range, but the lower limit is not limited to 60 ° C., and the oil temperature around 60 ° C., The upper limit is not limited to 80 ° C and can be set to an oil temperature of around 80 ° C.

  The special movement start duty ratio a ′% is a predetermined constant value as the duty ratio Rd that can start moving the connection pin 56 smaller than the standard movement start duty ratio a% and larger than the connection maintenance duty ratio b%. The optimum special movement start duty ratio a ′% corresponding to the oil temperature is obtained in advance and a map (map where the higher the oil temperature is, the smaller the special movement start duty ratio a ′%) is. Accordingly, by determining the special movement start duty ratio a ′%, it is possible to adjust the movement speed more suitable for the oil temperature and to stop the connection pin 56 at the connection position.

  The correlation between the oil temperature of the standard movement start duty ratio a and the special movement start duty ratio a ′% is obtained in advance and mapped to obtain the temperature state of the internal combustion engine (that is, the electromagnetic solenoid depending on the temperature) from the map. It is possible to more appropriately change the speed of the movable iron core members (61, 62) in accordance with the resistance change or the viscosity change of the lubricating oil) to suppress the occurrence of hitting sound.

1 ... motorcycle, 2 ... head pipe, 3 ... main frame, 4 ... down frame,
10 ... Internal combustion engine, 11 ... Crankcase, 12 ... Cylinder block, 13 ... Cylinder head, 14 ... Cylinder head cover, 15 ... Intake pipe, 16 ... Throttle body, 17 ... Air cleaner, 18 ... Exhaust pipe, 19 ... Muffler,
20 ... Fuel injection valve, 21 ... Piston, 22 ... Connecting rod, 25 ... Crankshaft, 26 ... Spark plug, 27 ... Oil temperature sensor,
30 ... Combustion chamber, 31 ... Intake port, 32 ... Exhaust port, 33 ... Intake valve, 34 ... Exhaust valve, 35 ... Intake valve spring, 36 ... Exhaust valve spring, 37 ... Coil spring, 38 ... Lifter,
40 ... Variable valve mechanism, 41 ... Cam shaft, 42, 43 ... Bearing, 44 ... Chain sprocket, 45 ..., 46 ..., 47 ... Intake rocker arm shaft, 48 ... Exhaust rocker arm shaft, 49 ...,
50 ..., 51 ... First intake rocker arm, 52 ... Second intake rocker arm, 53 ... Exhaust rocker arm, 54 ... Spring, 55 ... Plunger, 56 ... Connecting pin,
60 ... Electromagnetic solenoid, 61 ... Push rod, 62 ... Pressing body,
70: ECU.

Claims (8)

The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70) controls the duty of the electromagnetic solenoid (60) to drive the movable core member (61, 62),
The electromagnetic solenoid (60) is demagnetized in a connection release state in which the connection pin (56) is fitted into the other hole (52h) and the rocker arms (51, 52) can swing independently of each other. From the time when the electromagnetic solenoid (60) is duty controlled with a movement start duty ratio (a) for starting the movement of the connecting pin (56) against the biasing force of the spring (54), the movement start Change the duty ratio (b) smaller than the duty ratio (a) and repeat the duty control of the electromagnetic solenoid (60) multiple times, and adjust the moving speed of the movable core member (61, 62) The connecting pin (56) is pushed into the one hole (51h), and the both rocker arms (51, 52) are connected across both the holes (51h, 52h). Variable valve mechanism. After a lapse of a predetermined time (T) sufficient for the connection pins (56) to complete the connection of the rocker arms (51, 52), the electromagnetic solenoid (60) is fixed to the connection maintenance duty ratio (b). The variable valve mechanism for an internal combustion engine according to claim 1, wherein duty control is performed. Oil temperature detection means (27) for detecting the temperature of the lubricating oil of the internal combustion engine (10),
The control means (70)
Predetermined oil temperature range is set in advance between oil temperature approximately 60 ℃ and 80 ℃,
When the oil temperature detected by the oil temperature detecting means (27) is outside a predetermined oil temperature range, the standard movement start is started to move the connecting pin (56) against the urging force of the spring (54). Duty-controlling the electromagnetic solenoid (60) by duty-controlling the electromagnetic solenoid (60) by duty-controlling the electromagnetic solenoid (60) with a duty ratio (a) and then changing the connection-maintaining duty ratio (b) to be smaller than the standard movement start duty ratio (a) Repeat several times,
When the oil temperature detected by the oil temperature detecting means (27) is within a predetermined oil temperature range, the special movement start duty ratio is smaller than the standard movement start duty ratio (a) and larger than the connection maintenance duty ratio (b). claims, characterized in that repeated a plurality of times said to duty control the electromagnetic solenoid (60) by changing the connection maintaining duty ratio (b) after moving controls the coupling pin (56) in (a') A variable valve mechanism for an internal combustion engine according to claim 1 or 2 . The variable valve mechanism for an internal combustion engine according to claim 3, wherein the standard movement start duty ratio (a) and the special movement start duty ratio (a ') are determined from a map correlated with an oil temperature value. The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70)
Duty-controlling the electromagnetic solenoid (60) to drive the movable core member (61, 62) ,
The connection pin (56) straddles both the hole portions (51h, 52h) and maintains the state where the both rocker arms (51, 52) are connected. The variable valve mechanism for the internal combustion engine is characterized in that the movable core member (61, 62) is stopped by releasing the connection by adjusting the moving speed of the movable core member (61, 62) by controlling the movement of the movable core member (61, 62) . The rocker arms (51, 52), which are coaxially supported and adjacent to each other, swing in contact with cam lobes (41i, 41ii) having different camshaft profiles, respectively, and the intake valve (33) is swung by the rocker arm (51) swinging. Open and close
The rocker arms (51, 52) can be connected by moving the connecting pin (56) biased by the spring (54) between the holes (51h, 52h) formed in both rocker arms (51, 52). age,
The connecting pin (56) is moved by advancing and retracting the movable core member (61, 62) of the electromagnetic solenoid (60),
When the electromagnetic solenoid (60) is excited by the control means (70) and the movable core member (61, 62) protrudes, the connecting pin (56) moves against the urging force of the spring (54). In the variable valve mechanism of the internal combustion engine that couples both rocker arms (51, 52) and swings together,
The control means (70)
Duty-controlling the electromagnetic solenoid (60) to drive the movable core member (61, 62) ,
The duty ratio is set to 0 from the connection maintenance duty ratio (b) for maintaining the state where the both rocker arms (51, 52) are connected with the connection pin (56) straddling both the hole portions (51h, 52h). After that, at a predetermined timing, the brake duty ratio (b ′) which is smaller than the connection maintaining duty ratio (b) and larger than 0 is controlled to suppress the moving speed of the movable core members (61, 62). 61, 62) is stopped and the connection is released , A variable valve mechanism for an internal combustion engine. The variable valve mechanism for an internal combustion engine according to claim 6, wherein the brake duty ratio (b ') is determined from a map correlated with an oil temperature value. The position of the movable core member (61, 62) is detected by a position sensor and controlled at the predetermined position by the brake duty ratio (b ′) to suppress the moving speed of the movable core member (61, 62). The variable valve mechanism for an internal combustion engine according to claim 6, wherein the movable iron core member (61, 62) is stopped and the connection is released.

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