JP5369045B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine in which a longitudinal vortex (dumble) flow in a combustion chamber is enhanced by controlling the flow direction and flow velocity of the intake flow.

  Patent Document 1 proposes an intake device for an internal combustion engine that includes an airflow control valve and a partition plate in an intake port. The airflow control valve according to the present invention has a notch in the center, and controls the closing of the intake port according to operating conditions. By this closing control, a drift flow is generated in the intake port, and a dumble flow is generated in the combustion chamber (cylinder). At this time, since the airflow passing through the airflow control valve concentrates on the notch, the drift is promoted compared to the case where there is no notch, and the dumble flow can be further strengthened.

  Patent Document 2 discloses an intake device for an internal combustion engine including an airflow control valve having a support shaft in the vicinity of the center of the intake passage. The airflow control valve is rotationally controlled according to operating conditions, forms a predetermined flow path in the intake port according to the rotation direction, generates a drift in the intake port, and generates a dumble flow in the combustion chamber. At this time, since the support shaft is in the vicinity of the center of the airflow control valve, the torque applied in the rotation direction of the support shaft is canceled out, so that it is small. As a result, it is possible to reduce the load applied to the drive motor necessary for the angle holding and rotation driving, and the angle control reliability is increased.

JP 2006-283696 A JP 2007-135840 A

In the invention described in Patent Document 1, since the rotation of the airflow control valve is supported by the support shaft at the end, rotational torque is generated on the support shaft, the load on the actuator increases, and the cost for ensuring reliability increases. . Moreover, although it is the structure which concentrates a drift in a center part by a notch, in the case of control with a large aperture ratio, it becomes difficult to exhibit an effect.
In the invention described in Patent Document 2, the load on the actuator is light, but only three types of opening control, full open, substantially full close, and half open, can be performed. For this reason, a stepless opening corresponding to the operating conditions cannot be set, and the performance of generating a dumble flow in the combustion chamber is inferior.
In any invention, since the side of the intake passage in the range of movement of the valve needs to be flat around the airflow control valve, in an internal combustion engine equipped with the most common oblong oval cross section import, Requires major design changes.

  An object of the present invention is to provide an intake device capable of continuously controlling the opening degree even in an internal combustion engine having a general oblong intake port having an oblong cross section and capable of forming an optimal drift at all opening ratios. is there. That is, according to the present invention, by appropriately setting the shape of the air flow control valve, both performance and cost are achieved, the flow direction and flow velocity of the intake air flow are optimally controlled, and the vertical vortex (dumble) flow in the combustion chamber is achieved. To strengthen. As a result, the fuel, air, and EGR gas in the combustion chamber can be uniformly mixed in a wide range of operating conditions, and the engine can be stably operated even when a large amount of EGR is realized. As a result, the fuel efficiency of the internal combustion engine can be improved.

According to the first aspect of the present invention, there is provided an intake device for an internal combustion engine having an intake port having a substantially oblong shape with a cross-section that is substantially the same cross-sectional shape as the intake port inlet on the upstream side of the intake port. The air flow control valve is provided with an intake air control mechanism including an air intake passage having a left and right air flow control valves that are supported at approximately the center position in the vertical direction of the air intake passage by rotation support shafts. The left and right side walls have a cross section that follows the inner peripheral wall of the lower half of the intake passage, and gradually decrease in height toward the tip (downstream end), and a bottom plate that has a notch at the tip. It consists of a valve plate and the left and right rotating support shafts connected to the base end portions (upstream end portions) of the left and right side wall portions, and the bottom plate portion is an intake passage according to the operating conditions of the internal combustion engine. From the position where it contacts the bottom wall of the ceiling of the intake passage That is positioned rotated to close the first feature.
And between the outside of the base end portion of the airflow control valve and the inner wall of the intake passage, a substantially U-shaped auxiliary plate along the cross-sectional outline of the base end portion is connected to the left and right rotation support shafts. In addition, the second feature is that the gap between the air flow control valve and the inner wall of the intake passage is closed in conjunction with the air flow control valve.

  In the present invention, the airflow control valve having a cross section following the inner peripheral wall of the lower half of the intake passage and having a notch at the tip is rotated in accordance with the operating conditions of the internal combustion engine. The intake air is throttled to the upper side of the intake port by the half-nozzle-shaped air flow control valve to increase the speed and form an intake air flow. This accelerated intake air flow is sucked into the combustion chamber from the intake port, collides with the cylinder liner (combustion chamber side wall) opposite to the intake port and descends, and on the upper surface of the piston positioned lower in the intake stroke A tumble flow is formed by deflecting toward the center of the combustion chamber. By continuously controlling the airflow control valve according to the operating conditions of the internal combustion engine, a strong tumble flow can be formed according to all operating conditions, stable operation can be ensured even in lean combustion, and fuel efficiency can be secured. Improvement and emission improvement are possible.

  As described above, the present invention has been described by taking as an example the case of having a cross section along the inner peripheral wall of the lower half of the intake passage, but the air flow control having a cross section along the inner peripheral wall of the upper half of the intake passage Even if it is a valve and the structure which restrict | squeezes an intake passage to the lower side of an intake port, there is no difference in an effect. Whether the throttle part of the intake passage is on the lower side or the upper side is a design factor that differs depending on the engine. In the following embodiments, a configuration in which the upper side of the intake passage is restricted will be described as an example.

It is a schematic sectional drawing of the combustion chamber of an internal combustion engine. It is sectional drawing of an intake control mechanism, and a perspective view of an airflow control valve. It is a front view of an intake control mechanism. It is a schematic sectional drawing of the combustion chamber of an internal combustion engine. It is a schematic sectional drawing of the combustion chamber of an internal combustion engine. It is the perspective view and side view of an airflow control valve of Example 2. It is the perspective view and top sectional drawing of the airflow control valve of Example 3. FIG.

A mode for carrying out the invention will be described together with embodiments shown in the drawings. However, Examples 1 and 3 are reference examples showing an example to which the present invention is not applied, and Example 2 shows an example to which the present invention is applied.

  FIG. 1 shows a schematic cross section of an intake device for an internal combustion engine according to Embodiment 1 of the present invention, in which C is a cylinder body, CH is a cylinder head, and P is a piston. The cylinder head CH is provided with an intake port 2 communicating with the combustion chamber (cylinder) 1 via the intake port 21 and an exhaust port 3 communicating with the combustion chamber 1 via the exhaust port 31. An intake valve 22 and an exhaust valve 32 are installed in the intake port 21 and the exhaust port 31, respectively, and are opened and closed at a predetermined timing according to operations such as an intake stroke, a compression stroke, an ignition stroke, a combustion stroke, and an exhaust stroke of the internal combustion engine. The An ignition device 11 is attached to the ceiling portion of the combustion chamber 1 substantially at the center.

  The internal combustion engine is provided with an EGR passage 4 for supplying EGR gas from the exhaust passage 33 to the intake port 2. The outlet 41 of the EGR passage 4 opens to the upper wall surface 23 of the intake port 2, and an EGR valve 42 is interposed in the EGR passage 4. The EGR valve 42 is opened and closed according to the operating conditions of the internal combustion engine.

  In this embodiment, the intake port 2 has a horizontally long and substantially oval cross section (see FIG. 3). The intake port 2 is often used in an internal combustion engine provided with two intake valves 22 for each combustion chamber 1. Between the intake port 2 and the intake manifold 12, an intake control mechanism 5 which is the gist of the present invention is interposed.

  The intake control mechanism 5 includes a duct 52 having an intake passage 51 therein, and an actuator 57, as shown in FIGS. The duct 52 (intake passage 51) has a substantially oblong and substantially oval cross section that is substantially the same as the inlet cross section of the intake port 2. That is, the cross-section of the intake passage 51 has a maximum width at a substantially middle position in the vertical (upper and lower directions) direction.

  In the duct 52, an airflow control valve 6 for deflecting and increasing the intake air is rotatably installed. The duct 52 is intended for right and left, and has left and right side walls 53 and 53 that are substantially cylindrical surfaces, a substantially flat bottom wall 54, and a substantially flat ceiling wall 55, and is arranged in the longitudinal direction (in the direction of the intake passage 51). Are provided with fastening flanges 56, 56.

  As shown in FIGS. 2A and 2B, the air flow control valve 6 has both left and right rotating support shafts (support shafts) disposed through substantially the middle position of the duct 52 in the vertical (upper and lower directions) direction. 61, 61 and a valve plate 62 connected to both the support shafts 61, 61. The valve plate 62 includes left and right side plate portions 63 and 63 each having a substantially triangular plate shape that is curved along the left and right side walls 53 and 53 of the duct 52, and a bottom plate portion 64 that has a flat plate shape following the bottom wall 54 of the duct 52. Become. As shown in FIG. 2 (a), the portion excluding both ends of the bottom wall 54 is the lower end (bottom) of the inlet of the intake port 2 (see FIG. 1) by an amount substantially equal to the thickness (height) of the bottom plate portion 64. It is set lower than both ends of the wall 54.

  The side plate portions 63 and 63 are substantially cylindrical face plates as shown in FIG. 2B, and the side shapes are substantially triangular as shown in FIG. A base portion 65, 65 that is one vertex of the side plate portions 63, 63 is connected to both support shafts 61, 61. The side plate parts 63, 63 extend downward from the base parts 65, 65, and have upstream side edges 66, 66 having a length equal to the height from both the support shafts 61, 61 to the bottom wall 54. The side plate parts 63 and 63 have long sides 67 and 67 extending downstream, and the long sides 67 and 67 gradually approach the bottom plate part 64 as going downstream. As for the side surface shape of the side plate portions 63, 63, the apex angle α of the base portion 65 is practically in the range of 90 to 110 degrees and the tip angle β is in the range of 15 to 45 degrees.

  The bottom plate portion 64 is provided with a cylindrical surface portion 68 having the same center as the both support shafts 61, 61 on the downstream side from the upstream sides 66, 66. The cylindrical surface portion 68 is set so as to be in contact with or close to the bottom wall 54 of the duct 52, regardless of the rotational position of the valve plate 62, and from the gap between the bottom wall 54 and the valve plate 62 (cylindrical surface portion 68). The intake air is prevented from leaking. In addition, when the bottom plate portion 64 is not provided with the cylindrical surface portion 68 and is a flat plate, the valve plate 62 is rotated to cause a problem that intake air leaks from the gap between the bottom wall 54 and the valve plate 62.

  A notch 60 is provided at the center of the tip (downstream end) 69 of the bottom plate 64. In this embodiment, the notch 60 is a horizontally long slit. However, a notch having another shape such as a rectangle or a circle may be provided at the distal end portion 69 of the bottom plate portion 64, and other than the distal end portion 69 of the bottom plate portion 64. A structure in which a hole such as a slit, a rectangle, or a circle is formed at the tip of the substrate may be used.

  The operation will be described with reference to FIGS. 4 and 5 each show an intake device for an internal combustion engine in the intake stroke. An actuator 57 is connected to the support shaft 61, and the support shaft 61 is rotated by an engine control unit (ECU) in accordance with the operating conditions of the internal combustion engine. The airflow control valve 6 is rotated by the rotation of the support shaft 61, and the opening degree of the intake passage 51 is adjusted. In this embodiment, as the support shaft 61 rotates, the valve plate 62 rotates from the fully open position where the bottom plate portion 64 contacts the bottom wall 54 to the strongest throttle position where the tip portion 69 is close to the ceiling wall 55. .

  The airflow control valve 6 is set at the fully open position of the two-dot chain line in the figure when the internal combustion engine is operated at high load and high speed. In this state, since the valve plate 62 is buried in the bottom wall 54 of the duct 52, the problem of intake resistance is prevented. This is achieved by the bottom wall 54 being set lower than the lower end of the inlet of the intake port 2 by the thickness (height) of the bottom plate portion 64.

  When the internal combustion engine reaches predetermined operating conditions, the actuator 57 is actuated by a signal from the ECU, the support shaft 61 is rotated clockwise, and the valve plate 62 is rotated to a position where the intake passage 51 is narrowed as shown by the solid line in the figure. . When the intake air flow rate is low and the ignition condition by the ignition device is poor, such as low load and low speed operation, the valve plate 62 is positioned at the position where the tip 69 is close to the ceiling wall 55 as shown by the solid line in FIG. Is set.

  As a result, the intake air flow F is sucked into the combustion chamber 1 through the notch 60 in the front end portion 69 of the valve plate 62 as indicated by a white arrow. The intake air flow F flows along the upper surface of the bottom plate portion 64 and is gradually increased because the cross-sectional area of the flow path gradually decreases. Since the cross-sectional area of the flow path is minimized at the position of the notch 60, the flow velocity of the intake flow F is maximized at this position, and a jet flow state having a high flow velocity along the upper wall 23 of the intake port 2 is obtained.

  At this time, ventilation resistance is applied to the airflow control valve 6 from the intake airflow. The valve plate 62 is supported at a substantially intermediate position in the vertical direction by both support shafts 61 and 61. For this reason, the external force applied to the valve plate 62 is canceled by the upper and lower sides of the support shaft 61, and a large rotational torque T is prevented from increasing on both the support shafts 61, 61. As a result, the problem that the load of the actuator 57 required for maintaining and rotating the posture of the valve plate 62 is reliably reduced.

  The accelerated intake air flow F passes through the intake port 21 and is sucked into the central portion of the combustion chamber 1. The intake air flow F sucked into the combustion chamber 1 descends along the left side wall 13 of the combustion chamber 1, further collides with the piston P, and changes in the central direction. As a result, an imaginary tumble (longitudinal vortex) flow D is formed in the combustion chamber 1 as a whole. Further, when the internal combustion engine is in a predetermined operating condition, the EGR valve 42 is opened, EGR gas flows into the EGR passage 4, and EGR gas flows into the intake port 2 from the outlet 41. Thereby, in the combustion chamber 1, the mixture of intake air (fresh air), EGR gas, and injected fuel becomes uniform, the ignitability by the ignition device 11 is improved, and stable operation of the internal combustion engine can be ensured.

  FIG. 5 shows the intake device in a state where the internal combustion engine is operated at medium load and medium speed. The combustion chamber 1 is in the intake stroke, and the flow velocity of the intake flow F is medium. In the airflow control valve 6, the tip portion 69 of the valve plate 62 is set near the center of the intake passage 51. Even under this operating condition, the intake air flow F is concentrated along the plate 62 in the upper half of the intake passage 51, is accelerated, flows into the upper side of the intake port 2, flows in, and is sucked into the combustion chamber 1. To form a tumble flow D. For this reason, even if a large amount of EGR is performed, the output is maintained and fuel consumption is improved. In this case as well, the external force applied to the valve plate 62 is offset to some extent above and below the support shaft 61, and a large rotational torque T is prevented from being generated on both support shafts 61, 61.

  FIG. 6 shows an airflow control valve 7 according to the second embodiment, and the airflow control valve 7 includes a main valve plate 71 and auxiliary valve plates 72, 73, 74 for preventing leakage of intake air flow. The main valve plate 71 has substantially the same structure as the valve plate 62 (see FIG. 1). As shown in FIGS. 6A and 6B, the auxiliary valve plates 72, 73, and 74 include substantially left and right side plate portions 72 a to 74 a that are curved along the left and right side walls 53 and 53 of the duct 52, and the duct. The bottom plate 54 has flat plate portions 72 b to 74 b that follow the bottom wall 54 of the main plate 52, and is disposed so as to overlap between the base 75 of the main valve plate 71 and the inner wall of the duct 52.

  As the main valve plate 71 rotates, the auxiliary valve plates 72 and 73 rotate with a delay, and as shown in FIG. 6B, the base valve 75 and the bottom wall 54 of the main valve plate 71. To prevent intake air leakage. In this configuration, unlike the valve plate 62 (see FIG. 1) of the first embodiment, it is not necessary to provide the cylindrical surface portion 68 (see FIG. 1) on the bottom plate portion 64 (see FIG. 1), and the airflow control valve 6 (see FIG. 1). 2) in the fully open state as shown in FIG. 2 (a), it is possible to reduce the problem that the rear end of the bottom plate portion 64 extends into the ventilation channel 51 and the ventilation resistance increases.

  FIG. 7A shows an airflow control valve 8 according to the third embodiment. The airflow control valve 8 has substantially the same structure as the airflow control valve 6 of the first embodiment, but 2 at the tip of the valve plate 82. Two notches 80, 80 are provided. As shown in FIG. 7B, the two notches 80 and 80 are directed to the two intake ports 21 and 21 provided in the cylinder head CH of the combustion chamber 1. The intake jets F1 and F2 that have passed through the two notches 80 and 80 are independently sucked into the two intake holes 21 and 21, respectively. As a result, in the internal combustion engine provided with the two intake ports 21, the tumble in the combustion chamber can be formed more strongly.

  In the intake device for an internal combustion engine of the present invention, a strong tumble flow can be reliably formed in the combustion chamber under a wide range of operating conditions. For this reason, stable ignition and combustion can be realized even in low load and low speed operation such as idling operation, EGR can be increased to the maximum, and fuel efficiency is improved.

C Cylinder body CH Cylinder head 1 Combustion chamber 2 Intake port 21 Intake port 22 Intake valve 3 Exhaust port 4 EGR passage 41 Outlet 42 EGR valve 5 Intake control mechanism 6, 7, 8 Airflow control valve

Claims (1)

An intake device for an internal combustion engine having an intake port having a substantially oblong cross section in cross section,
An intake passage having substantially the same cross-sectional shape as the inlet of the intake port on the upstream side of the intake port, and an airflow control valve supported on the left and right sides by a rotation support shaft at a substantially central position in the vertical direction of the intake passage In an intake device for an internal combustion engine provided with an intake control mechanism comprising:
The air flow control valve has a cross-section that follows the inner peripheral wall of the lower half of the intake passage, a left and right side wall that gradually decreases in height toward the tip (downstream end), and a bottom plate that has a notch in the tip. A valve plate provided with a portion, and the left and right rotating support shafts connected to the base end portion (upstream end portion) of the left and right side wall portions,
According to the operating conditions of the internal combustion engine, the valve plate is rotated from a position where the bottom plate portion comes into contact with the bottom wall of the intake passage to a position where the tip portion is close to the ceiling wall of the intake passage . ,
Between the outer side of the base end portion of the airflow control valve and the inner wall of the intake passage, a substantially U-shaped auxiliary plate along the cross-sectional outline of the base end portion is connected to the left and right rotation support shafts. An intake device for an internal combustion engine characterized by being arranged and interlocking with the airflow control valve to close a gap between the airflow control valve and the inner wall of the intake passage .

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