JP2005171813A - Intake system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure full-open performance while maintaining a driving force of an intake control valve small, in an intake system for strengthening an intake air flow by closing one of divided passages of an intake port by an intake control valve. <P>SOLUTION: A valve element 12A of the intake control valve 12 is rotatable around a valve shaft 12a which is disposed at the center of the valve element, and is journaled at an eccentric position of a crank plate to be rotatable around the valve shaft 12a. The valve shaft 12a is movable along a cross-section of a passage by rotation of the crank plate 22. A position closing a lower passage 4B of the intake port, and a position opening the valve element 12A by positioning the valve shaft 12a on an extension of the lower passage 4B, and a position opening the valve element 12A by positioning the valve shaft 12a on an extension of a dividing plate 10 are changed over depending on an operational status. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an intake device that controls intake air flow of an internal combustion engine.

The passage cross section of the intake port is divided by a partition wall, and an intake control valve having a valve shaft at the center of the valve body is interposed in one of the divided passages, and the intake control valve is closed under a low load condition. There is an intake device for an internal combustion engine in which intake air is circulated only from the inside to enhance the intake flow and generate a tumble flow (Patent Document 1).
JP-A-6-159203

However, in the above-described conventional intake device, even when the intake control valve is opened under the fully-open operation condition, the thickness of the intake control valve located on the extension of the divided passage becomes a resistance to reduce the intake charging efficiency. , Fully open performance will be impaired.
Considering this point, if the intake control valve has a valve shaft in the vicinity of the downstream end of the partition wall and a valve body on only one side of the valve shaft, the valve body is positioned on the extension of the partition wall when fully opened. In addition, since it is possible to suppress the intake resistance, the fully open performance can be secured. However, in this structure, when one passage divided by the intake control valve is closed, a large closing torque is generated around the valve shaft by the intake negative pressure acting on the valve body from the closed passage. Therefore, when the load increases from this state to open the intake control valve, a large driving torque in the opening direction is required, and it is necessary to provide a high-power actuator, and the layout becomes difficult due to high cost.

  The present invention has been made paying attention to such a conventional problem, and provides an intake device for an internal combustion engine capable of ensuring fully open performance while reducing the drive torque of an intake control valve that controls intake flow. For the purpose.

  For this reason, the present invention divides the passage cross section of the intake port by the dividing wall, allows the intake control valve to freely rotate around the valve shaft provided at the center of the valve body, and moves the valve shaft in the passage cross section direction. The intake control valve is opened and closed while controlling the rotation around the valve shaft and the movement of the valve shaft along the passage cross-sectional direction by a valve drive mechanism.

  In this way, since the valve shaft is provided on the central axis of the valve body, the torque acting on the valve body on both sides across the valve shaft due to the intake pressure is generated in the opposite direction and is canceled. The drive torque can be reduced, and at the time of high output such as during fully open operation, the valve stem is moved fully open so that the valve body overlaps the extension of the dividing wall, so that the intake control valve does not become resistance and fully open output Performance can be secured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a system configuration of an internal combustion engine provided with an intake device according to the present invention.
The internal combustion engine 1 includes two intake valves 2 and two exhaust valves 3 for each cylinder, and includes two intake ports 4 and two exhaust ports 5 extending to the intake valves 2 and the exhaust valves 3. A spark plug 7 is provided at the center of the top wall of the combustion chamber 6, a fuel injection valve 8 is provided below the two intake ports 4, and fuel is injected toward a cavity 9 a formed in the piston 9, The ignition plug 7 is ignited and burned.

  A dividing plate (dividing wall) 10 that is vertically divided is disposed in the intake port 4, and is divided into an upper passage 11 </ b> A and a lower passage 11 </ b> B by the dividing plate 10. An intake control valve 12 is disposed at the downstream end of the dividing plate 10. The intake control valve 12 includes a valve shaft 12a at the center of the valve body 12A, and rotates around the valve shaft 12a to open and close. A valve drive mechanism 13 for driving the intake control valve 12 while moving its valve shaft 12 a along the passage section of the intake port 4 is provided. The valve drive mechanism 13 is controlled by a signal from an engine control unit (ECU) 14.

  FIG. 2 shows the configuration of the valve drive mechanism 13. Cylindrical flange portions 21 projecting outward are formed on both side walls of the intake port 4, and disc-shaped crank plates (crankshaft members) 22 are respectively fitted to these flange portions 21 so as to freely slide and rotate around the central axis. To do. These crank plates 22 are provided with valve shaft mounting holes 22a, and both end portions of the valve shaft 12a provided at the center of the valve body 12A of the intake control valve 12 are passed through the valve shaft mounting holes 22a. Attached so as to be freely slidable and rotatable around the central axis of 12a. One end of the valve shaft 12a is inserted through the valve shaft mounting hole 22a so as to protrude to the outside of the crank plate 22.

  The following link mechanism is connected to the side where the end of the valve shaft 12a protrudes outward. A stopper pin 22b is planted in an eccentric position on the outer wall of the crank plate 22 on the flange portion 21 side, and both ends are locked to the stopper pin 22b and a pin 23 planted on the outer wall of the intake port 4. A return spring 24 is provided. The crank plate 22 is urged clockwise in the drawing by the pulling force of the return spring 24, and the stopper pin 22b is abutted against the stopper wall 30 provided on the outer wall of the intake port 4, thereby Regulate the amount of rotation.

An arm 25 is connected to the end of the valve shaft 12a protruding outside the crank plate 22, and the upper end of the link 26 is pivotally supported at one end of the arm 25 so that the lower end of the link 26 is supported. The rack 27 that moves straight in the vertical direction is pivotally supported freely. The pinion 28 meshed with the teeth of the rack 27 is rotationally driven by a motor 29 fixed to the bottom wall of the intake port 4.
Further, a pair of stopper walls 4 a and 4 b that are free to contact with both side edges of the lower end of the arm 25 are provided on the outer wall of the intake port 4. The left side edge of the lower end of the arm 25 is in contact with the stopper wall 4a so that rotation in the clockwise direction in the figure is restricted, and the integrated valve body 12A is lowered via the arm 25 and the valve shaft 12a. The valve body 12A is in the closed position where the side passage 11B is closed, and the right side edge of the lower end of the arm 25 is in contact with the stopper wall 4b and the rotation in the counterclockwise direction in the figure is restricted. The members are connected so as to be in the open position in parallel with the axial direction. Thereby, the arm 25 and the valve body 12A rotate within the rotation angle range from the closed position to the open position.

  Here, the stopper wall 4b is a crank connected to the arm 25 while maintaining the rotational position of the arm 25 in a state where the lower edge of the arm 25 is in contact with the stopper wall 4b as will be described later. In order to enable the plate 22 to rotate counterclockwise in the figure, it is formed in an arc shape that matches the rotation locus of the center of the valve shaft 12a when the crank plate 22 rotates. In order to make this rotation smooth, a moderate play is given to the connecting portion between the arm 25 and the link 26. Note that a return spring that urges the arm 25 clockwise in the drawing may be provided so that the valve body 12A is held in the closed position when the motor 29 is stopped.

Further, when the crank plate 22 connected to the arm 25 is rotated around the central axis of the crank plate 22, the valve shaft 12 a passing through the valve shaft mounting hole 22 a of the crank plate 22 around the central axis of the crank plate 22. The rotation (revolution) is transmitted to the opposite crank plate 22, and the crank plate 22 also rotates by the same amount.
Next, a series of operations of the intake control valve 12 by the valve drive mechanism will be described with reference to FIG.

In a state where the motor 29 is stopped, the crank plate 22 is held at a rotational position where the stopper pin 22b abuts against a stopper wall 21a provided on the flange portion 21 by the urging force of the return spring 24, and the valve shaft 12a is It is located on the lowermost side in the figure and is located on the extension of the lower passage 11B [see FIG. 3 (B)].
In this state, the valve body 12A can rotate around the valve shaft 12a with the rotational position of the crank plate 22 held as described above to open and close the lower passage 11B.

  Then, the motor 29 is driven to rotate the pinion 28 counterclockwise in FIG. 2 from the rotational position where the lower edge of the arm 25 is in contact with the stopper wall 4a, that is, the valve body 12a is in the open position. Then, the rack 27 moves upward in the figure, and the arm 25 and the valve body 12A integrally rotate around the valve shaft 12a via the link 26 counterclockwise in the figure, and the lower end side edge of the arm 25 is the stopper. When the rotation position that contacts the wall 4b, that is, the valve body 12A is positioned parallel to the axis of the lower passage 11B and has the maximum opening, the rotation of the arm 25 in the same direction is restricted [FIG. )reference].

  In this state, when the motor 29 is further rotationally driven in the same direction, the lower edge of the arm 25 slides on the arc-shaped stopper wall 4b while maintaining the rotational position of the arm 25 around the valve shaft 12a. The crank plate 22 rotates counterclockwise in the figure against the urging force of the return spring 24, and at the same time, the valve shaft 12a moves upward in the figure. Then, as shown by a one-dot chain line in FIG. 2, the valve body 12 </ b> A rotates until the valve plate 12 </ b> A is located on the extension of the divided plate 10, that is, the fully open position where the opening area of the intake port 4 is maximized. In addition, you may provide the stopper which controls the rotation of the same direction at this position [refer FIG.3 (D)].

  When the motor 29 is rotationally driven in the reverse direction (clockwise in the figure) from the fully opened position, the valve is closed while following the same course as the valve opening operation. That is, the pulling force of the return spring 24 causes the valve body 12A to move downward in the clockwise direction in the drawing of the crank plate 22 while maintaining the maximum opening in parallel with the passage shaft, and the stopper pin 22b is moved to the stopper wall 21a. The rotation in the same direction is restricted at the rotational position of the abutting crank plate 22, and thereafter, the arm 25 and the valve body 12A rotate around the valve shaft 12a, and the lower edge of the arm 25 contacts the stopper wall 4a. The valve body 12A closes the lower passage 11B at the contact rotational position.

Next, the control of the intake control valve 12 according to the operating state (control of the position of the valve body 12A) will be described with reference to FIGS.
In the low rotation and low load region (I in FIG. 3), stratified combustion is performed. However, since the intake air amount is small and the gas flow is weak, it is difficult to stably obtain a good stratified mixture by using the gas flow.
Therefore, as shown in FIGS. 5A and 5B, the air-fuel mixture is sent around the spark plug 7 by the flow energy of the fuel spray injected from the fuel injection valve 8 so that stable stratified combustion can be obtained. In this case, it is not preferable to cause disturbance in the intake air flow by closing the lower passage 11B by the intake control valve 12, because it causes an influence such as combustion cycle variation and stable stratified combustion cannot be obtained. That is, the intake control valve 12 is opened so as to eliminate the variation in gas flow as much as possible. Further, the valve body 12A is connected to the passage shaft on the extension of the lower passage 11B so as to further eliminate the disturbance of the intake flow. Control to open parallel and open. When the valve body 12A is controlled to this position, the flow direction of the intake air introduced into the lower passage 11B is guided and rectified by the valve body 12A positioned in parallel with the passage axis of the lower passage 11B. A stable intake flow without variation is obtained. Thereby, a stable stratified combustion operation can be performed in the low rotation low load region I.

  On the other hand, in the middle / high rotation / low load region (II in FIG. 3), the gas flow becomes strong, so that the valve body 12A is closed and the lower passage 11B is closed to forcibly introduce the intake air into only the upper passage 4A. As a result, as shown in FIGS. 5C and 5D, the gas flow is strengthened and a strong tumble flow can be obtained, and the fuel spray is transported around the spark plug 7 by the tumble flow and homogeneous mixing is performed. It is possible to obtain a good and homogeneous combustion operation. Note that EGR is performed in the region IIA in the figure, and EGR is stopped in the region IIB where the rotation and load are higher outside this region.

  Further, in the fully open and high rotation high load region close to full open (III in FIG. 3), the intake control valve 12 is controlled to the fully open position where the valve shaft 12 a and the valve body 12 A are positioned on the extension of the split plate 10. Thereby, since the thickness of the valve shaft 12a and the valve body 12A overlaps with the thickness of the dividing plate 10, the opening area of the intake port 4 is maximized, and the output performance can be secured by maximizing the intake air amount.

Note that the region shown below the dotted line in the drawing of the high rotation / high load region III is both when the control of the intake control valve 12 is switched between the region above the region and the middle / high rotation / low load region. This is a transitional region where the control position of the region is switched.
Next, the effect of the present invention shown in the above embodiment is the one described in Patent Document 1 and the one provided with an intake control valve having a valve body only on one side of the valve shaft (hereinafter referred to as a comparative example). And will be described.

As described above, in Patent Document 1, in the fully open operation, the valve shaft position remains fixed on the extension of the lower passage and is fully opened as the maximum opening. Therefore, in addition to the thickness of the dividing wall that divides the intake port, The thickness of the intake control valve located on the extension of the lower passage reduces the passage cross-sectional area of the intake port and increases the resistance.
On the other hand, in the present invention, as described above, during the fully open operation, the passage resistance due to the thickness of the valve shaft 12a and the valve body 12A intake control valve 12 can be reduced, so that the maximum intake air amount can be increased and the fully open output performance can be improved. .

Further, in the comparative example, as described above, when the valve body is rotated from the state where the intake control valve is closed and the lower passage is closed to the fully opened position, the torque in the closing direction around the valve shaft due to the intake negative pressure is increased. In order to open the valve against this, a large driving torque is required, a large actuator is required, and the layout is difficult due to high cost.
On the other hand, in the present invention, the driving torque when the valve is opened can be made sufficiently small. That is, since the valve shaft 12a is provided at the center of the valve body 12A, first, when the valve body 12A is rotated around the valve shaft 12a from the closed position to the maximum opening, the valve shafts 12a are sandwiched between the valve shafts 12a. Since the torque acting on the body part in response to the intake pressure is generated in the opposite direction and canceled out, the drive torque can be sufficiently small. Further, when driving to the fully open position, after maintaining the valve shaft position and rotating the valve body 12A to the maximum opening degree as described above, the division plate 11 is extended with the maximum opening degree maintained. Therefore, the negative torque resistance applied to the valve body 12A is kept to a minimum while the valve body 12A is rotated to the fully open position, and the driving torque can be sufficiently reduced. By the way, when sudden acceleration is performed from the closed position to switch to the fully opened position, the opening continuously increases (the crank plate and the valve body rotate integrally) without first setting the maximum opening. Therefore, the valve opening drive torque against the valve closing torque due to the intake negative pressure acting on the entire valve body 12A is required, which is the same as the comparative example.

As described above, according to the present invention, the intake resistance during the fully open operation is suppressed to be small, the maximum output is improved, the valve opening torque is kept small, the cost can be reduced by using a small actuator, and the layout is also easy.
In the embodiment, the intake port is divided into upper and lower parts to generate the tumble flow when the lower passage is closed, but the upper passage is not limited to the one that generates the tumble flow, and the intake control valve The present invention can also be applied to a case where the tumble flow is generated by closing and the tidal flow is reversed, or the swirl is generated by dividing the intake port into left and right and closing one of the passages.

The system block diagram of the internal combustion engine provided with the intake device which concerns on this invention. Sectional drawing which shows the function of the valve drive mechanism of the intake control valve in an intake device same as the above. The figure which shows a series of operation | movement and each control position of an intake control valve same as the above. The figure which shows the control position for every engine operation area | region of an intake control valve same as the above. The figure which shows the difference in the air-fuel | gaseous mixture production | generation method of the stratified combustion operation in a low rotation low load area | region, and the stratified combustion operation in a medium high rotation low load area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 4 ... Intake port 4A ... Upper side passage 4B ... Lower side passage 4a ... Stopper wall 4b ... Stopper wall 7 ... Spark plug 8 ... Fuel injection valve 10 ... Split plate 12 ... Intake control valve 12A ... Valve body 12a ... Valve Shaft 13 ... Valve drive mechanism 14 ... Engine control unit 22 ... Crank plate 22b ... Stopper pin 23 ... Pin 24 ... Return spring 25 ... Arm 26 ... Link 27 ... Rack 28 ... Pinion 29 ... Motor 30 ... Stopper wall

Claims (7)

  An intake control valve in which a passage cross section of the intake port is divided by a dividing wall, and is freely rotatable around a valve shaft provided in a central portion of the valve body, and the valve shaft is freely movable along the passage cross sectional direction. And a valve drive mechanism for opening and closing the intake control valve while controlling rotation around the valve shaft and movement of the valve shaft along the passage cross-sectional direction. apparatus.   The valve drive mechanism drives the intake control valve while moving the valve shaft from a position on an extension of the dividing wall to a position on an extension of a passage divided by the dividing wall. The intake device for an internal combustion engine according to claim 1.   3. The intake device for an internal combustion engine according to claim 2, wherein the valve driving mechanism positions the valve shaft and the valve body on an extension of the dividing wall during full opening of the engine and high load operation close to full opening.   4. The drive mechanism according to claim 2, wherein the valve drive mechanism drives the valve shaft so as to be closed on an extension of the passage when the passage divided by the dividing wall is closed. 5. An intake device for an internal combustion engine.   The valve drive mechanism positions the valve body in parallel with the axial direction of the passage while positioning the valve shaft on an extension of the passage divided by the dividing wall under a predetermined operating condition. An intake device for an internal combustion engine according to any one of claims 2 to 4.   When the valve body of the intake control valve is opened from a state where the divided passage is closed, the valve driving mechanism is arranged around the valve shaft to a position where the valve body is opened in parallel with the axis of the divided passage. After the rotation, the valve shaft is moved until it is positioned on the extension of the dividing wall while maintaining the rotation position of the valve shaft to be fully opened, and when the valve is closed from the fully opened state, The intake device for an internal combustion engine according to any one of claims 2 to 5, wherein the intake device is configured to operate in a reverse direction. The valve drive mechanism supports the crankshaft member on the intake port wall so as to freely rotate, and pivotally supports the valve shaft at an eccentric position of the crankshaft member, thereby providing a rotation range of the valve shaft. A stopper mechanism for restricting is provided, a link mechanism is connected to the end of the valve shaft, and by driving the link mechanism, the valve body is rotated around the valve shaft by a rotation range restricted by the stopper mechanism, The intake device for an internal combustion engine according to claim 6, wherein the valve shaft is moved by rotating the crankshaft member through the valve shaft that is restricted from rotating.

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