JP5331343B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that can change a drive phase of an intake valve, an exhaust valve, and the like and a valve lift amount.

  In an internal combustion engine such as an automobile engine, the drive phase and lift amount of the intake and exhaust valves are changed according to the operating state of the internal combustion engine to purify the exhaust gas exhausted from the engine or reduce the fuel consumption of the automobile. Such variable valve gears are known.

  As such a variable valve operating apparatus, a third arm is provided between a first arm that drives a valve and a second arm that is swung by a cam, and the second arm is driven through the third arm. One having a continuously variable rocker arm mechanism in which the phase and lift amount of the valve are continuously changed by displacing the swing fulcrum of the arm is known (for example, see Patent Document 1).

  The variable valve operating apparatus having such a continuously variable rocker arm mechanism can improve the fuel efficiency by adjusting the lift amount and phase of the valve to clean the exhaust gas and adjust the valve opening angle.

  On the other hand, a switchable rocker arm that is provided with a mechanism for selectively transmitting displacement between a first arm that drives a valve and a second arm that is swung by a cam, and operates or stops the first arm. One having a mechanism is known (for example, see Patent Document 2).

Such a variable valve mechanism having a switchable rocker arm mechanism performs internal EGR by opening the exhaust valve in the intake stroke to clean the exhaust gas, and opens the exhaust valve at the compression top dead center. It is possible to apply.
JP 2006-144743 A JP 2005-105953 A

  However, the variable valve operating apparatus as described above must select either the switching rocker arm mechanism 40 or the continuously variable rocker arm mechanism 50, and can only exhibit a single function of each. The switchable rocker arm mechanism 40 can be operated instantaneously, but has a drawback that fine adjustment of the lift amount and phase of the valve does not work. On the other hand, the continuously variable rocker arm mechanism 50 has fine adjustment of the lift amount and phase. However, there was a problem that the operation took about 1 second and the response was poor.

  Accordingly, the present invention provides a variable valve operating apparatus for an internal combustion engine that can execute an internal EGR and apply an engine brake, and can simultaneously exhibit a plurality of functions of improving fuel efficiency and cleaning exhaust gas. With the goal.

  In the present invention, in order to achieve the above object, a variable valve operating apparatus for an internal combustion engine is configured as follows.

(1) A camshaft that is rotatably provided on a cylinder head of an internal combustion engine, a rocker shaft that is swingably provided on the internal combustion engine, and an intake valve and an exhaust valve that are swingably supported by the rocker shaft. A shared rocker arm formed so as to be able to drive at least one of the valves, a storage cylinder provided in the shared rocker arm, having a hollow portion and a window portion, a piston having a notch portion reciprocally accommodated in the hollow portion, A spring that biases the piston so that the notch is positioned at the window, and a hydraulic pressure that can be supplied to the hollow portion, and the piston is moved in a direction in which the spring is compressed by the hydraulic pressure. in, transmission mechanism having a hydraulic supply mechanism for exposing the periphery of the piston to the window, and, formed on the camshaft Ru is driven by arm, the swingably provided on the rocker shaft, provided with a switching rocker arm having an outer peripheral and can abut the abutment arm of the piston located in the window portion, of the piston to the window When the outer periphery is exposed, the abutting arm hits the outer periphery of the piston, so that the displacement from the switching rocker arm is selectively transmitted to the common rocker arm, and the valve is opened and closed. a switchable rocker arm mechanism for switching the lift amount stepwise, the drives said common rocker arm by being driven by a formed cam on the camshaft, closing at least one of the valve of the exhaust valve and the intake and exhaust valves as well as comprising a continuous variable rocker arm mechanism for varying the lift amount continuously, the There.

The variable valve device for an internal combustion engine according to (2) (1), wherein the continuous variable rocker arm mechanism is driven by the pre-Symbol cam swingably provided around the fulcrum provided on the rocker shaft side An intermediate arm provided between the shared rocker arm and the continuous variable arm, and provided between the intermediate arm and the continuous variable arm. A conversion member that transmits the swing displacement of the continuously variable arm to the shared rocker arm via the intermediate arm, and a drive mechanism that swings the rocker shaft to displace the fulcrum.

(3) In the variable valve operating apparatus for an internal combustion engine according to (1), the internal combustion engine includes the continuously variable rocker arm mechanism on the intake side and the switchable rocker arm mechanism on the exhaust side. When the engine is in the intake stroke, the exhaust valve is opened by the switching rocker arm mechanism, and the valve opening timing of the intake valve is quickly closed by the continuously variable rocker arm mechanism.

(4) In the variable valve operating apparatus for an internal combustion engine according to (1), the internal combustion engine includes the exhaust valve driven by the switching rocker arm mechanism and the exhaust valve driven by the continuously variable rocker arm mechanism. At least one per cylinder, and when the internal combustion engine is near compression top dead center, the exhaust valve is opened by the switchable rocker arm mechanism, and the exhaust valve is opened by the continuously variable rocker arm mechanism. Open the valve opening time early.

According to the variable valve operating apparatus described in (1), by opening and closing the valve using both the continuously variable rocker arm mechanism and the switching rocker arm mechanism, the valve opening / closing timing is instantaneously switched and the lift amount is finely adjusted. A plurality of functions such as control can be realized simultaneously.

According to the variable valve operating apparatus described in (1) , the valve can be opened and closed without delay in timing by selectively transmitting the oscillating displacement as necessary.

According to the variable valve operating apparatus described in (2) , the drive phase and lift amount of the valve can be finely controlled by continuously transmitting the oscillation displacement.

According to the variable valve operating apparatus described in (3) , the exhaust gas can be cleaned by performing the internal EGR and finely adjusting the EGR amount.

According to the variable valve operating apparatus described in (4) , the engine brake can be operated and the effect can be increased.

  FIG. 1 is a plan view showing a main part of a cylinder head 10 incorporating a variable valve device 20 for an internal combustion engine according to a first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line A and viewed in the direction of the arrow, FIG. 3 is a cross-sectional view taken along line BB in FIG. 1 of the cylinder head 10 and viewed in the direction of the arrow, and FIG. FIG. 5 is an exploded perspective view showing the variable valve device 20.

As shown in FIGS. 1 to 3, the cylinder head 10 is provided with a pair of intake valves 12 and 13 and a pair of exhaust valves 14 and 15. Intake valve 12, 13 is provided with can reciprocate in the intake passage path of the cylinder head 10 in the axial direction, and is always biased in a direction to close the intake passage path valve spring 12a, by 13a. Exhaust valves 14 and 15, is provided with can reciprocate in an exhaust passage path of the cylinder head 10 in the axial direction, and is always biased in a direction to close the intake passage path valve spring 14a, by 15a. The cylinder 11 is attached to a cylinder block (not shown) below the cylinder head 10.

  The variable valve gear 20 is a valve gear that drives the valves of the internal combustion engine to open and close, and is provided in pairs with the cylinder 11 in between. Since the pair of variable valve devices 20 have a symmetrical structure with the cylinder 11 in between, only the variable valve devices 20 on the exhaust valves 14 and 15 side will be described, and the intake valves 12 and 13 on the side. Description of the variable valve device 20 is omitted.

  The cylinder head 10 is driven by a pair of cam shafts 21 provided rotatably, a pair of rocker shafts 30 provided so as to be swingable, and a cam 22 formed on the cam shaft 21, and the intake valves 12, 13 and the exhaust valves 14 and 15 are opened and closed, and driven by a pair of switchable rocker arm mechanisms 40 that switch the lift amount in stages, and a cam 23 formed on the camshaft 21, and the intake valves 12 and 13 and the exhaust valves are exhausted. A pair of continuously variable rocker arm mechanisms 50 that open and close the valves 14 and 15 and continuously vary the lift amount are provided. The switchable rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50 share the rocker arm 60.

  The camshaft 21 and the rocker shaft 30 are connected to a crankshaft (not shown) of an internal combustion engine via a cam chain, a gear, and the like. When the crankshaft rotates, cams 22 and 23 having different cam profiles are indicated by arrows R. It is rotationally driven in the direction shown. The cams 22 and 23 drive the variable valve gear 20 at a predetermined timing as will be described later.

  An oil passage 31 to which engine oil is supplied is provided inside the rocker shaft 30. A hydraulic pressure supply mechanism 80 that supplies engine oil is connected to the oil passage 31. In addition, the rocker shaft 30 includes a drive mechanism 90 that controls the rotational angle position around the axis. Furthermore, a notch 32 is formed at a position corresponding to the continuously variable rocker arm mechanism 50 of the rocker shaft 30.

  Next, the switchable rocker arm mechanism 40 will be described with reference to FIGS. The switchable rocker arm mechanism 40 is supported by the rocker shaft 30 so as to be swingable, and is driven by the common rocker arm 60 formed to be able to drive the exhaust valves 14 and 15 and the cam 22 so as to be swingable on the rocker shaft 30. The switching rocker arm 41 is provided.

  The switching rocker arm 41 protrudes upward from the boss portion 41a supported by the rocker shaft 30 in a swingable manner, and enters the window portion 71b of the vertical piston structure 70 as a transmission mechanism described later. A retreating butting arm 41b and a roller 41c are swingably provided. When the roller 41c comes into contact with the cam 22 and the cam 22 rotates, the switching rocker arm 41 is swung around the axis of the rocker shaft 30 as a fulcrum. Further, the switching rocker arm 41 is formed with a groove 41d.

  In FIG. 5, reference numeral 42 denotes a torsion coil spring. A bent portion 42a is formed on one end side, and an operating portion 42b extending in the axial direction of the rocker shaft 30 and further bent outward in the radial direction is formed on the other end side. Is formed. The bent portion 42 a is inserted into the cylinder head 10. When the operating portion 42 b of the torsion coil spring 42 is engaged in the groove 41 d, the torsion coil spring 42 biases the switching rocker arm 41 so that the roller 41 c follows the cam 22.

  The shared rocker arm 60 is pressed by a boss portion 61 fitted to the rocker shaft 30 so as to be swingable, arms 62 and 63 extending from the boss portion 61 toward the exhaust valves 14 and 15, and a pressing portion 53 b described later. Pressure receiving portion 64. A flow path 61 a for guiding engine oil from the oil passage 31 is provided in the boss portion 61.

  The boss portion 61 is provided with a cylindrical vertical piston structure 70 as a transmission mechanism for selectively transmitting the displacement from the switching rocker arm 41 to the common rocker arm 60. The vertical piston structure 70 includes a storage cylinder 71 having a hollow portion 71a extending to the inner surface of the boss portion 61 and a side window portion 71b, a lid member 72 for closing the upper end opening of the hollow portion 71a of the storage cylinder 71, and a hollow The piston 73 accommodated in the part 71a so that reciprocation is possible, and the spring 74 which is provided in the cover member 72 and urges | biases the piston 73 to the boss | hub part 61 side is provided. The piston 73 is provided with a notch 73a, and is usually set so that the notch 73a comes to the position of the window 71b by the action of a spring 74. When hydraulic pressure is applied by the hydraulic pressure supply mechanism 80, engine oil is supplied from the oil passage 31 to the hollow portion 71a, compressing the spring 74 and pushing up the piston 73. Thereby, the outer periphery of the piston 73 is exposed to the window portion 71b. Conversely, when the hydraulic pressure is released, the piston 73 is pushed down by the action of the spring 74. The hydraulic pressure can be turned on and off instantaneously.

  In addition, an abutting arm 41b is disposed to face the window portion 71b. When the notch 73a is positioned in the window 71b, the abutting arm 41b moves idle in the notch 73a. When the outer periphery of the piston 73 is positioned in the window 71b, the abutting arm 41b abuts on the outer periphery. However, it is formed in a shape that moves.

  Thereby, when the abutting arm 41b of the arm 41 does not abut against the piston 73, the cam displacement from the switching rocker arm 41 is not transmitted to the common rocker arm 60, and when the abutting arm 41b abuts against the piston 73, the switching rocker arm. The cam displacement from 41 opens the exhaust valves 14 and 15 via the shared rocker arm 60. Further, the rocker shaft 30 is formed with an oil discharge chamber 32 wider than the flow path 61 a on the downstream side of the oil passage 31. The rocker shaft 30 is switched in accordance with the rocking of the rocker shaft 30 itself or the rotation of the cam 22. Even if the rocker arm 41 swings and the position of the flow path 61a changes, the engine oil can be supplied to the hollow portion 71a. The width of the oil discharge chamber 32 is larger than the distance by which the switching rocker arm 41 swings, and the engine oil can be supplied to the flow path 61a even when the rocker shaft 30 reaches the maximum swing position. The size is preferred.

  Further, an oil introduction chamber 75 wider than the flow path 61a is formed in the vertical piston structure 70 on the upstream side of the hollow portion 71a, and the switching rocker arm 41 swings and flows as the cam 22 rotates. Even if the position of the path 61a changes, the engine oil can be supplied to the hollow portion 71a. The width of the oil introduction chamber 75 is preferably larger than the distance by which the switching rocker arm 41 swings.

  Next, the continuously variable rocker arm mechanism 50 will be described with reference to FIGS. The continuously variable rocker arm mechanism 50 is swingably supported by the rocker shaft 30 and is driven by the common rocker arm 60 formed so as to be able to drive the exhaust valves 14 and 15 and the cam 23, and is provided on the rocker shaft 30 side. A continuously variable arm 53 provided so as to be swingable about a fulcrum Q, and a shared rocker arm 60 provided between the shared rocker arm 60 and the continuously variable arm 53, and transmitting the swing displacement of the continuously variable arm 53 to the shared rocker arm 60. And an intermediate arm 51 for driving 60.

  The intermediate arm 51 includes an annular shaft fitting portion 51a and a pressing portion 51b protruding in the radial direction from the shaft fitting portion 51a. The pressing portion 51b is provided with a roller 51c. When the intermediate arm 51 swings about the rocker shaft 30, the pressing portion 53 b presses the pressure receiving portion 64 of the shared rocker arm 60, and the shared rocker arm 60 opens the exhaust valves 14 and 15.

  The continuously variable arm 53 includes a connecting member 54 that connects the continuously variable arm 53 and the rocker shaft 30. The connecting member 54 is a stud bolt, has a spherical universal joint portion 54a on one end side, is screwed into a screw hole 33 formed in the notch portion 32 of the rocker shaft 30, and is fixed by a lock nut 54b. When the connecting member 54 is fixed to the rocker shaft 30, the universal joint portion 54 a functions as the fulcrum Q.

  5 denotes a torsion coil spring having a bent portion 55a formed on one end side thereof, and an operating portion extending in the axial direction of the rocker shaft 30 and further bent radially outward on the other end side. 55b is formed. The bent portion 55a is inserted into the cylinder head 10.

  The continuously variable arm 53 is formed in a substantially U shape in a side view, and is provided with a base end portion 53a on the lower side and a contact portion 53b on the upper side of the figure formed in the U shape. ing. The base end portion 53a has a recess 53c formed on the upper surface. The concave portion 53c is formed in a substantially hemispherical shape corresponding to the spherical shape of the universal joint portion 54a, and is slidably assembled with the universal joint portion 54a as a fulcrum.

  Further, the continuously variable arm 53 is provided with a roller 53d swingably at an intermediate position between the base end portion 53a and the contact portion 53b. When the roller 53d comes into contact with the cam 23 and the cam 23 rotates, the continuously variable arm 53 is swung around the center of the universal joint portion 54a.

  Moreover, 56 in the figure has shown the conversion member. The conversion member 56 is formed in a triangular trapezoidal shape with one end side elongated, and a sliding surface portion 56a is provided on the upper surface in FIG. 5, and a transmission surface portion 56b is provided on the lower surface in the drawing. The sliding surface portion 56 a is formed to be equal to the curvature of the pad 57 (see FIG. 9) fixed to the cylinder head 10, and slides and moves in an arc along the lower surface of the pad 57.

  The transmission surface portion 56b is formed such that the distance from the sliding surface portion 56a has a predetermined value along the sliding surface portion 56a. That is, when the conversion member 56 is slid in a circular arc along the lower surface of the pad 57, the member that contacts the transmission surface portion 56b at a predetermined position moves in a direction perpendicular to the pad 57 as the conversion member 56 moves. It is formed to make a movement.

  Further, a groove 56c is formed in the transmission surface portion 56b, and the operating portion 55b of the torsion coil spring 55 is engaged in the groove 56c. When the operating portion 55b is engaged in the groove portion 56c, the torsion coil spring 55 biases the conversion member 56 so that the conversion member 56 moves to the conversion arm 53 side.

  Further, a semi-cylindrical joint 57 is provided between the conversion member 56 and the contact portion 53 b of the continuously variable arm 53. The joint 57 is attached to the contact portion 53b of the continuously variable arm 53 and is slidably fitted to the conversion member 56, and absorbs a change in the contact angle between the conversion member 56 and the contact portion 53b. In addition, the pressing operation of the continuously variable arm 53 is transmitted to the conversion member 56.

  Next, the operation of the continuously variable rocker arm mechanism 50 will be described with reference to FIG. When retarding the opening or closing timing of the exhaust valve, the rocker shaft 30 is swung in the direction in which the universal joint portion 54a of the connecting member 54 approaches the exhaust valves 14 and 15 side with respect to the neutral position by the drive mechanism 90. Moved.

  In the continuously variable arm 53, the base end portion 53a is pulled leftward by the universal joint portion 54a, and the whole is moved leftward. On the other hand, the conversion member 56 is urged toward the conversion arm 53 by the torsion coil spring 55. Therefore, the conversion member 56 is in close contact with the pad 57 and the roller 53 d is in contact with the cam 23. At this time, since the camshaft 21 is counterclockwise, the angle between the point at which the cam crest starts and the contact point between the roller 53d and the cam 23 is set farthest, and the conversion arm 53 is moved by the cam 23 later than in the neutral case. As a result, the opening or closing timing of the valve is retarded.

  On the other hand, when the opening or closing timing of the exhaust valve is advanced, the universal joint portion 54a of the connecting member 54 is swung in a direction away from the exhaust valves 14 and 15 with respect to the neutral position.

  In the continuously variable arm 53, the base end portion 53a is pulled rightward by the universal joint portion 54a and moved as a whole to the right. On the other hand, the conversion member 56 is urged toward the conversion arm 53 by the torsion coil spring 55. Therefore, the conversion member 56 is in close contact with the pad 57 and the roller 53 d is in contact with the cam 23.

  At this time, since the camshaft 21 is counterclockwise, the angle between the point at which the cam crest starts and the contact point between the roller 53d and the cam 23 is set to be the narrowest, and the conversion arm 53 is moved by the cam 23 earlier than in the neutral case. As a result, the opening or closing timing of the exhaust valve is advanced.

  It should be noted that the above adjustment of the retard angle and advance angle is performed continuously by continuously adjusting the angle position of the rocker shaft 30.

  As described above, since the variable valve operating apparatus 20 can change the valve opening timing and the valve closing timing by swinging the rocker shaft 30 by the drive mechanism 90, the valve opening timing and the valve closing timing can be changed. By changing it, the intake air amount is increased, and the effect of reducing fuel consumption can be obtained.

  In the internal combustion engine configured as described above and including the variable valve operating apparatus 20 having the switching rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50, the following control can be performed.

First, the operation of the switching rocker arm mechanism 40 and the operation of the continuously variable rocker arm mechanism 50 when the internal EGR amount is optimized will be described by comparing “normal operation” and “internal EGR operation”. FIG. 6 is a graph showing the relationship between the phase of the camshaft 21 and the lift amount, where EX is the opening (lift) of the exhaust valves 14 and 15, and IN is the opening of the intake valves 12 and 13 (lifting). Lift).

<Normal operation>
The camshaft 21 slightly overlaps the exhaust stroke for opening the exhaust valves 14 and 15 and the intake stroke by opening the intake valves 12 and 13. The operation of the switching rocker arm mechanism 40 at this time is shown in FIG. 8, and the operation of the continuously variable rocker arm mechanism 50 is shown in FIG. In normal operation, the operation mode of the switching rocker arm mechanism 40 is OFF and the operation mode of the continuously variable rocker arm mechanism 50 is normal (neutral) on both the intake valves 12 and 13 side and the exhaust valves 14 and 15 side.

  That is, when the operation mode of the switchable rocker arm mechanism 40 is turned OFF, the hydraulic pressure by the hydraulic pressure supply mechanism 80 is not applied, and the engine oil is not supplied to the hollow portion 71a in the switchable rocker arm mechanism 40. For this reason, the piston 73 is biased downward by the elastic force of the spring 74, and the notch 73a is located in the window 71b. On the other hand, the rotation of the cam 22 by the camshaft 21 moves the roller 41c along the cam 22, and the switching rocker arm 41 swings around the rocker shaft 30 in the direction of arrow E in FIG. However, even when the abutting arm 41b enters the window 71b, it only enters the notch 73a and does not contact the piston 73. Therefore, the movement of the switching rocker arm 41 is not transmitted to the shared rocker arm 60, and eventually the switching rocker arm mechanism 40 does not operate, and the intake valves 12, 13 and the exhaust valves 14, 15 are not driven.

  In the continuously variable rocker arm mechanism 50, the drive mechanism 90 sets the rocker shaft 30 to the neutral position. Accordingly, the rotation of the cam 23 by the camshaft 21 moves the roller 53d along the cam 23, and the continuously variable arm 53 swings around the rocker shaft 30 in the direction of arrow F in FIG. As a result, the movement of the continuously variable arm 53 is transmitted to the shared rocker arm 60 via the conversion member 56 and the intermediate arm 51, and the intake valves 12 and 13 and the exhaust valves 14 and 15 are driven according to the profile of the cam 23.

  As described above, in the normal operation, the continuously variable rocker arm mechanism 50 drives the intake valves 12 and 13 and the exhaust valves 14 and 15 with the phase and lift amount along the solid line S.

<Internal EGR operation>
In the internal EGR operation, the operation mode of the switching rocker arm mechanism 40 on the intake valves 12 and 13 side is OFF, and the operation mode of the continuously variable rocker arm mechanism 50 is early closing (advance). The operation mode of the switching rocker arm mechanism 40 on the exhaust valves 14 and 15 side is ON, and the operation mode of the continuously variable rocker arm mechanism 50 is normal (neutral).

The operations of the switching rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50 are summarized as follows.

  When the operation mode of the switching rocker arm mechanism 40 on the exhaust valves 14 and 15 side is turned ON, the hydraulic pressure is applied by the hydraulic pressure supply mechanism 80, and in the switching rocker arm mechanism 40, as shown in FIG. Supplied. For this reason, the piston 73 rises against the elastic force of the spring 74, and the outer periphery of the piston 73 is positioned in the window portion 71b. On the other hand, the rotation of the cam 22 by the camshaft 21 moves the roller 41c along the cam 22, and the switching rocker arm 41 swings around the rocker shaft 30 in the direction of arrow E in FIG. When the abutting arm 41b enters the window portion 71b, it comes into contact with the outer periphery of the piston 73. Therefore, the movement of the switching rocker arm 41 is transmitted to the shared rocker arm 60, and the exhaust valves 14 and 15 are driven according to the profile of the cam 22. A peak 22a of the cam 22 corresponds to P in FIG.

  In the continuously variable rocker arm mechanism 50 on the intake valves 12 and 13 side, the rocker shaft 30 is rotated counterclockwise by a predetermined angle by the drive mechanism 90 to the advance angle position, and the swing fulcrum of the continuously variable arm 53 is Move away from intake valves 12 and 13. In this state, the rotation of the cam 23 by the cam shaft 21 causes the roller 53d to move along the cam 23, and the continuously variable arm 53 swings around the rocker shaft 30 in the direction of arrow F in FIG. . As a result, the movement of the continuously variable arm 53 is transmitted to the shared rocker arm 60 via the conversion member 56 and the intermediate arm 51, and the intake valves 12 and 13 are driven in a state of being advanced with respect to the profile of the cam 23.

  As described above, in the internal EGR operation, the intake valves 12 and 13 are driven by the continuously variable rocker arm mechanism 50 and the exhaust valves 14 and 15 are driven by the switching rocker arm mechanism 40 in the intake stroke. Accordingly, the intake valves 12 and 13 are opened at the phase and lift amount indicated by S in FIG. 6 and the exhaust valves 14 and 15 are indicated by P in FIG. That is, the exhaust valves 14 and 15 are opened at the timing shown in FIG. 6P, that is, the valves are opened in the intake stroke, so that the exhaust gas once exhausted from the cylinder 11 is once taken into the cylinder 11 and the internal EGR It becomes operation.

  Since the lift amount of the exhaust valves 14 and 15 at this time is constant, the internal EGR amount is constant. On the other hand, since the operating state of the engine is not constant, the required EGR amount is different, so this fine adjustment is performed by the operation of the intake valves 12 and 13. That is, in order to prevent the internal EGR amount from becoming excessively low and NOx from decreasing, the intake air amount itself can be reduced by increasing the closing end of the intake valves 12 and 13, and the internal EGR amount relatively increases. It becomes. FIG. 7 shows the relationship between the closing end phase of the intake valves 12 and 13 and the air amount, and the relationship between the closing end phase of the intake valves 12 and 13 and the internal EGR amount. By closing the intake valves 12 and 13 in the phase S1 or S2 slightly earlier than the standard closing end phase S0, the air amount is reduced and the internal EGR amount is increased.

  As described above, by operating the switching rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50 in a coordinated manner, a more appropriate amount of EGR can be obtained and the exhaust gas can be cleaned.

Next, the operation of the switching rocker arm mechanism 40 and the operation of the continuously variable rocker arm mechanism 50 when the engine brake is operated will be described by comparing “normal operation” and “engine brake operation”. FIG. 12 is a graph showing the relationship between the phase of the camshaft 21 and the lift amount, where EX is the valve opening (lift) of the exhaust valves 14 and 15, and IN is the valve opening of the intake valves 12 and 13 (lift). Lift).

<Normal operation>
The camshaft 21 slightly overlaps the exhaust stroke for opening the exhaust valves 14 and 15 and the intake stroke by opening the intake valves 12 and 13. The operation of the switching rocker arm mechanism 40 at this time is shown in FIG. 8, and the operation of the continuously variable rocker arm mechanism 50 is shown in FIG. In normal operation, the operation mode of the switching rocker arm mechanism 40 is OFF and the operation mode of the continuously variable rocker arm mechanism 50 is normal (neutral) on both the intake valves 12 and 13 side and the exhaust valves 14 and 15 side.

  The operation of the switching rocker arm mechanism 40 during normal operation and the operation of the continuously variable rocker arm mechanism 50 are the same as those shown in FIGS.

<Engine brake operation>
When the engine brake is operated, the operation mode of the switching rocker arm mechanism 40 on the intake valves 12 and 13 side is OFF, and the operation mode of the continuously variable rocker arm mechanism 50 is normal (neutral). The operation mode of the switchable rocker arm mechanism 40 on the exhaust valves 14 and 15 side is ON, and the operation mode of the continuously variable rocker arm mechanism 50 is early open (advance).

The operations of the switching rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50 are summarized as follows.

  When the operation mode of the switchable rocker arm mechanism 40 on the exhaust valves 14 and 15 side is turned ON, hydraulic pressure is applied by the hydraulic pressure supply mechanism 80, and in the switchable rocker arm mechanism 40, as shown in FIG. 14, engine oil enters the hollow portion 71a. Supplied. For this reason, the piston 73 rises against the elastic force of the spring 74, and the outer periphery of the piston 73 is positioned in the window portion 71b. On the other hand, the rotation of the cam 22 by the camshaft 21 moves the roller 41c along the cam 22, and the switching rocker arm 41 swings around the rocker shaft 30 in the direction of arrow E in the figure at regular intervals. When the abutting arm 41b enters the window portion 71b, it comes into contact with the outer periphery of the piston 73. Therefore, the movement of the switching rocker arm 41 is transmitted to the shared rocker arm 60, and the exhaust valves 14 and 15 are driven according to the profile of the cam 22. The peak portion 22b of the cam 22 corresponds to L in FIG.

  Further, as shown in FIG. 15, in the continuously variable rocker arm mechanism 50 on the exhaust valves 14 and 15 side, the rocker shaft 30 is rotated counterclockwise by a predetermined angle by the drive mechanism 90 to be an advance angle position, and continuously variable. The swing fulcrum of the arm 53 is moved away from the intake valves 12 and 13. In this state, the rotation of the cam 23 by the cam shaft 21 causes the roller 53d to move along the cam 23, and the continuously variable arm 53 swings around the rocker shaft 30 in the direction of arrow F in FIG. . As a result, the movement of the continuously variable arm 51 is transmitted to the shared rocker arm 60 via the conversion member 56 and the intermediate arm 51, and the intake valves 12 and 13 are driven in a state of being advanced with respect to the profile of the cam 23.

As described above, in the engine brake operation, the intake valves 12 and 13 are driven by the continuously variable rocker arm mechanism 50, and the exhaust valves 14 and 15 are driven by both the switchable rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50. Is done. Therefore, exhaust valves 14 and 15 so that the opened with a phase and the lift amount shown in FIG. 12 in M and L. That is, the switchable rocker arm mechanism 40 opens the exhaust valves 14 and 15 at the timing indicated by L in FIG. 12, that is, the exhaust valves 14 and 15 are opened at the compression top dead center (TDC), and the compression brake is activated. . Since the lift amount of the exhaust valves 14 and 15 is constant, the braking effect is constant.

  On the other hand, since the operating state of the engine is not constant and the required braking force is different, this fine adjustment is performed by the operation of the exhaust valves 14 and 15 driven by the continuously variable rocker arm mechanism 50. That is, the exhaust energy (air amount) can be increased by setting the start of opening of the exhaust valves 14 and 15 to a phase M1 or M2 slightly earlier than the standard phase M0, and by advancing the valve opening timing. The braking force will be increased. FIG. 13 shows the relationship between the opening start phase of the exhaust valves 14 and 15 and the exhaust energy (air amount), and the relationship between the opening start phase of the exhaust valves 14 and 15 and the engine braking force.

  As described above, by operating the switching rocker arm mechanism 40 and the continuously variable rocker arm mechanism 50 in a coordinated manner, a more appropriate engine braking force can be obtained and a good driving feeling can be obtained.

As described above, according to the variable valve operating apparatus 20 for an internal combustion engine according to the present embodiment, a plurality of functions such as execution of internal EGR and engine braking can be performed, as well as improvement in fuel consumption and cleaner exhaust gas. Can be exhibited simultaneously.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] A camshaft rotatably provided on a cylinder head of an internal combustion engine;
A rocker shaft provided swingably in the internal combustion engine;
A continuously variable rocker arm mechanism that is driven by a cam formed on the camshaft, opens and closes at least one of an intake valve and an exhaust valve, and continuously varies the lift amount;
An internal combustion engine comprising a switchable rocker arm mechanism that is driven by a cam formed on the camshaft and opens and closes at least one of an intake valve and an exhaust valve and switches a lift amount in stages. Variable valve gear for engine.
[2] The switchable rocker arm mechanism is
A shared rocker arm that is swingably supported by the rocker shaft and configured to drive the valve;
A switching rocker arm driven by the cam and provided on the rocker shaft so as to be swingable;
The variable valve operating apparatus for an internal combustion engine according to [1], further comprising a transmission mechanism that selectively transmits the displacement from the switching rocker arm to the common rocker arm.
[3] The continuously variable rocker arm mechanism is:
A shared arm that is swingably supported by the rocker shaft and configured to drive the valve;
A continuously variable arm driven by the cam and provided so as to be swingable about a fulcrum provided on the rocker shaft side;
An intermediate arm supported by the rocker shaft in a swingable manner and provided between the shared arm and the continuously variable arm;
A conversion member that is provided between the intermediate arm and the continuously variable arm, and transmits the swing displacement of the continuously variable arm to the common arm via the intermediate arm;
The variable valve operating apparatus for an internal combustion engine according to [1], further comprising a drive mechanism that swings the rocker shaft to displace the fulcrum.
[4] The internal combustion engine includes the continuously variable rocker arm mechanism on the intake side, and the switchable rocker arm mechanism on the exhaust side.
When the internal combustion engine is in the intake stroke, the exhaust valve is opened by the switching rocker arm mechanism, and the valve opening timing of the intake valve is quickly closed by the continuously variable rocker arm mechanism. ] The variable valve operating apparatus for an internal combustion engine according to any of the above.
[5] The internal combustion engine includes at least one exhaust valve driven by the switching rocker arm mechanism and at least one exhaust valve driven by the continuously variable rocker arm mechanism.
When the internal combustion engine is in the vicinity of compression top dead center, the exhaust valve is opened by the switching rocker arm mechanism, and the opening timing of the exhaust valve is quickly opened by the continuously variable rocker arm mechanism. The variable valve operating apparatus for an internal combustion engine according to [1].

The top view which shows the principal part of the cylinder block in which the variable valve apparatus concerning this invention was integrated. Sectional drawing which cut | disconnected the cylinder head block by the AA line in FIG. 1, and looked at the arrow direction. Sectional drawing which cut | disconnected the cylinder head block by the BB line in FIG. 1, and looked at the arrow direction. The perspective view which shows the variable valve apparatus. The disassembled perspective view which shows the variable valve operating apparatus. Explanatory drawing which shows the control concept at the time of performing internal EGR. Explanatory drawing which shows the control concept at the time of performing internal EGR. Sectional drawing which shows operation | movement of the switching rocker arm mechanism at the time of normal driving | operation. Sectional drawing which shows operation | movement of the continuously variable rocker arm mechanism at the time of normal driving | operation. Sectional drawing which shows operation | movement of the switching rocker arm mechanism at the time of performing internal EGR. Sectional drawing which shows operation | movement of the continuously variable rocker arm mechanism at the time of performing internal EGR. Explanatory drawing which shows the control concept at the time of performing an engine brake. Explanatory drawing which shows the control concept at the time of performing an engine brake. Sectional drawing which shows operation | movement of the switching rocker arm mechanism at the time of performing engine braking. Sectional drawing which shows operation | movement of the continuously variable rocker arm mechanism at the time of performing engine braking.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cylinder head, 12, 13 ... Intake valve, 14, 15 ... Exhaust valve, 20 ... Variable valve gear, 21 ... Cam shaft, 22, 23 ... Cam, 30 ... Rocker shaft, 40 ... Switchable rocker arm mechanism, 41 ... switching rocker arm, 50 ... continuously variable rocker arm mechanism, 53 ... continuously variable arm, 60 ... shared rocker arm.

Claims (4)

A camshaft rotatably provided on a cylinder head of an internal combustion engine;
A rocker shaft provided swingably in the internal combustion engine;
A shared rocker arm that is swingably supported by the rocker shaft and is configured to drive at least one of an intake valve and an exhaust valve;
A storage cylinder provided on the shared rocker arm and having a hollow portion and a window portion, a piston which is reciprocably accommodated in the hollow portion and having a notch portion, and the piston is attached so that the notch portion is located in the window portion. And a hydraulic pressure supply mechanism which is formed so as to be able to supply hydraulic pressure to the hollow portion and exposes the outer periphery of the piston to the window portion by moving the piston in a direction in which the spring is compressed by the hydraulic pressure. transmission mechanism having, as well, the Ru is driven by the formed cam on the camshaft, swingably provided on the rocker shaft, the outer periphery and capable of abutting abutment arms of the piston located at the window A switching rocker arm, and when the outer periphery of the piston is exposed to the window portion, the abutting arm projects to the outer periphery of the piston. By hitting, convey a displacement from the switching rocker arm to selectively said transmission mechanism a displacement to said common rocker arm, as well as open and close the valve, the switchable rocker arm mechanism for switching the lift stepwise,
The drives the shared rocker arm by being driven by a cam formed on the camshaft, the with the intake and exhaust valves for opening and closing at least one of the valve of the exhaust valve, continuously variable continuously variable the lift Rocker arm mechanism ,
Variable valve device for an internal combustion engine, characterized in that it comprises a. The continuously variable rocker arm mechanism is :
Driven by pre Symbol cam, a continuously variable arm swingable about a fulcrum provided on the rocker shaft side,
An intermediate arm supported on the rocker shaft in a swingable manner and provided between the shared rocker arm and the continuously variable arm;
A conversion member that is provided between the intermediate arm and the continuously variable arm, and transmits the swing displacement of the continuously variable arm to the common rocker arm via the intermediate arm;
The variable valve operating apparatus for an internal combustion engine according to claim 1, further comprising a drive mechanism that swings the rocker shaft to displace the fulcrum. The internal combustion engine includes the continuously variable rocker arm mechanism on the intake side and the switchable rocker arm mechanism on the exhaust side,
2. The exhaust valve is opened by the switchable rocker arm mechanism when the internal combustion engine is in an intake stroke, and the valve opening timing of the intake valve is quickly closed by the continuously variable rocker arm mechanism. 2. A variable valve operating apparatus for an internal combustion engine according to 1. The internal combustion engine includes at least one exhaust valve driven by the switchable rocker arm mechanism and one exhaust valve driven by the continuously variable rocker arm mechanism, one per cylinder,
When the internal combustion engine is in the vicinity of compression top dead center, the exhaust valve is opened by the switching rocker arm mechanism, and the opening timing of the exhaust valve is quickly opened by the continuously variable rocker arm mechanism. The variable valve operating apparatus for an internal combustion engine according to claim 1.

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