JP2005256673A - Air intake device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air intake device capable of changing relation between flow rate of intake gas flowing into a combustion chamber and intensity of swirl generated in intake gas in the combustion chamber in a wide range. <P>SOLUTION: This air intake device is provided with air intake ports 5, 6 communicating to a combustion chamber 4 and a bypass passage 22 communicating to the air intake port in a vicinity of the combustion chamber. A direction and position change mean changing direction in which intake gas flows out from a bypass passage into the air intake port and a position where intake gas flows out from the bypass passage into the air intake port to change intensity of swirl generated in air intake gas in the combustion chamber is provided in a zone where the bypass passage communicates to the air intake port. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an intake device for an internal combustion engine.

  In an internal combustion engine, a swirl (swirl flow) is generated in the intake gas supplied into the combustion chamber (cylinder bore) to promote mixing of air and fuel in the combustion chamber, and efficient combustion in the combustion chamber is achieved. There is something that is made to do. The strength of the swirl required to achieve intake gas mixing and efficient combustion in the combustion chamber varies depending on operating conditions, so the strength of the swirl of the intake gas generated in the combustion chamber can be changed. Is preferred.

  Patent Document 1 discloses an apparatus including a main intake passage that forms an intake port and generates a swirl, and a sub intake passage that introduces intake gas in a direction that opens to the intake port and suppresses the swirl. ing. The main intake passage is provided with an intake control valve for controlling the flow rate of the intake gas flowing through the main intake passage, and the auxiliary intake passage communicates with the main intake passage on the upstream side of the intake control valve. If the opening of the intake control valve is reduced, the flow rate of the intake gas flowing through the main intake passage decreases, but the flow rate of the intake gas flowing through the auxiliary intake passage increases, resulting in a weaker swirl in the intake gas in the combustion chamber. . Conversely, when the opening degree of the intake control valve is increased, the flow rate of the intake gas flowing through the main intake passage increases, but the flow rate of the intake gas flowing through the auxiliary intake passage decreases, and as a result, the swirl becomes stronger. Thus, in the apparatus of Patent Document 1, the strength of the swirl generated in the combustion chamber is adjusted according to the opening of the intake control valve.

  Patent Document 2 includes two main passages opened to one combustion chamber and a sub-passage that bypasses the main passage, and an angle at which intake gas flows out from the sub-passage to the main passage for each sub-passage. An air intake device in which the air pressure is made different is disclosed. The device described in Patent Document 2 is also provided with a control valve for controlling the flow rate of the intake gas flowing through the main passage in the main passage downstream of the branch portion to the sub passage. The auxiliary passage is formed so that the swirl generated in the intake gas in the combustion chamber becomes stronger as the flow rate of the intake gas flowing through the auxiliary passage increases. Therefore, if the control valve opening is reduced, the flow rate of the intake gas flowing through the main passage decreases, but the flow rate of the intake gas flowing through the sub-passage increases, so that the swirl becomes stronger. The swirl becomes weaker. As described above, in the apparatus described in Patent Document 2, as with the apparatus described in Patent Document 1, the strength of the swirl is adjusted according to the opening degree of the intake valve.

JP-A 63-309721 JP-A-9-273427 JP-A-9-317483 JP 60-219414 A Japanese Patent Laid-Open No. 62-45930

  In the device described in Patent Document 1, when the opening of the intake control valve is reduced, the flow rate of the intake gas flowing through the auxiliary intake passage increases and the swirl becomes weak, but the flow rate of the intake gas flowing through the main intake passage is reduced. As a result, the overall intake gas flow rate is reduced. On the other hand, when the opening degree of the intake control valve is increased, the flow rate of the intake gas flowing through the auxiliary intake passage decreases and the swirl becomes stronger, but the flow rate of the intake gas flowing through the main intake passage increases, resulting in an overall The intake gas flow rate increases. That is, it is impossible to change only the strength of the swirl, and the flow rate of the intake gas is changed with the change of the strength of the swirl.

  The same applies to the device described in Patent Document 2. That is, if the control valve opening is reduced, the swirl becomes stronger, but the overall intake gas flow rate decreases. Conversely, if the control valve opening is increased, the overall intake gas flow rate increases, but the swirl is weak. Become. Therefore, even in the device described in Patent Document 2, it is not possible to change only the strength of the swirl, and the flow rate of the intake gas is changed with the change of the strength of the swirl.

  In other words, in the above device, when the strength of the swirl is determined, the overall intake gas flow rate (that is, the flow resistance to the intake gas) is also uniquely determined. Conversely, the overall intake gas flow rate is Once determined, the strength of the swirl is uniquely determined. That is, the relationship between the swirl strength and the flow rate of the intake gas is always a fixed relationship, and it is not possible to change only the strength of the swirl or only the flow rate of the intake gas.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an intake device for an internal combustion engine capable of changing the relationship between the flow rate of intake gas flowing out into the combustion chamber and the strength of swirl generated in the intake gas in the combustion chamber over a wide range.

In order to solve the above-mentioned problem, in the first invention, in the intake device for an internal combustion engine comprising an intake port communicating with the combustion chamber and a bypass passage communicating with the intake port in the vicinity of the combustion chamber, the bypass passage In the region communicating with the intake port, the intake gas in the combustion chamber is changed by changing at least one of the direction in which the intake gas flows out from the bypass passage into the intake port and the position in which the intake gas flows out into the intake port from the bypass passage Direction / position changing means for changing the strength of the swirl generated in
According to the first invention, the strength of swirl generated in the intake gas in the combustion chamber is changed without changing the flow rate of the intake gas flowing out into the combustion chamber by changing the direction in which the intake gas flows out from the bypass passage. be able to. Further, by changing the position where the intake gas flows out into the intake port, the swirl strength can be reduced while reducing the flow rate of the intake gas flowing out into the combustion chamber, or vice versa. Accordingly, the degree of freedom in changing the relationship between the flow rate of the intake gas flowing into the combustion chamber and the strength of the swirl can be increased.

According to a second invention, there is provided a flow rate adjusting means for adjusting the flow rate of the intake gas flowing out from the bypass passage into the combustion chamber in the first invention.
According to the second invention, in addition to changing the direction in which the intake gas flows out from the bypass passage or the position in which the intake gas flows out into the intake port by the direction / position changing means, the flow rate adjusting means Since the flow rate of the intake gas is adjusted, the degree of freedom in changing the relationship between the flow rate of the intake gas and the strength of the swirl can be increased.

In the third invention, in the first or second invention, a plurality of intake ports are provided per cylinder, and the bypass passage and the direction / position changing means are located upstream of the plurality of intake ports arranged in the swirl direction in the swirl direction. It is provided only at the intake port on the side.
Normally, when a plurality of intake ports are provided per cylinder, the intake port on the upstream side in the swirl turning direction has a lower swirl generation capability. This is because, in the intake port downstream of the swirl turning direction, the flow direction of the intake gas in the intake port is close to the tangential direction of the combustion chamber in the region where the intake port is connected to the combustion chamber. In the third aspect of the present invention, by providing the direction / position changing means to the intake port having a low swirl generation capability, the swirl generated in the intake gas in the combustion chamber can be strengthened more effectively.

According to a fourth invention, in any one of the first to third inventions, a plurality of intake ports are provided per cylinder, and one of the intake ports has a flow rate for adjusting a flow rate of intake gas flowing through the intake port. A regulating valve is provided.
According to the fourth aspect of the invention, the degree of freedom in changing the relationship between the flow rate of the intake gas and the strength of the swirl can be made higher.

  According to a fifth invention, in the invention according to any one of the first to fourth inventions, a sleeve partially embedded in the inner wall surface of the intake port is provided at the tip of the bypass passage as the direction / position changing means. The sleeve has an inlet for the intake gas directed at an angle with respect to the axis thereof, and is movable relative to the intake port. At least one of the sliding movements in the axial direction of the sleeve is possible.

  According to the present invention, the degree of freedom in changing the relationship between the flow rate of the intake gas flowing out into the combustion chamber and the strength of the swirl can be increased, and thus the flow rate of the intake gas flowing out into the combustion chamber and the intake air in the combustion chamber can be increased. The relationship with the strength of the swirl generated in the gas can be varied over a wide range.

  Hereinafter, the present invention will be described in detail with reference to the drawings. First, an embodiment of an intake device of the present invention will be described with reference to FIGS. 1 is a schematic plan view around the intake port and the intake valve, FIG. 2 is a cross-sectional view around the intake port and the intake valve in FIG. 1, and FIG. 3 is an intake view along the line III-III in FIG. Sectional drawing around a port and an intake valve is shown.

  As shown in FIGS. 1 to 3, the internal combustion engine 1 includes a cylinder block 2 and a cylinder head 3 disposed on the cylinder block 2. The cylinder block 2 is provided with a plurality of cylinder bores at predetermined intervals. A piston (not shown) reciprocates in each cylinder bore, and a combustion chamber 4 is defined between the cylinder bore and the piston. In this specification, the direction from the cylinder block 2 toward the cylinder head 3 is referred to as upward, and the direction from the cylinder head 3 toward the cylinder block 2 is referred to as downward.

  For each combustion chamber 4, two intake ports 5, 6 and two exhaust ports (not shown) are communicated. The intake ports 5 and 6 and the exhaust port are provided in the cylinder head 3. An intake valve 7 is disposed between the intake ports 5 and 6 and the combustion chamber 4, and the intake ports 5 and 6 and the cylinder bore 4 are fluidly connected or disconnected by opening and closing the intake valve 7. Each intake valve 7 has a valve body 8 that actually acts as a valve and a stem 9 connected to the valve body 8, and reciprocates along the stem 9. Similarly, an exhaust valve is disposed between the exhaust port and the combustion chamber 4, and the exhaust valve fluidly connects or disconnects the exhaust port and the combustion chamber 4.

  The intake ports 5 and 6 are provided at the tip thereof and have a spiral portion (hereinafter referred to as “spiral portion”) 10 that communicates with the combustion chamber 4, and an intake manifold at the inlet end portion 11 that communicates with the spiral portion 10. This is a helical intake port having a port introduction portion 12 connected to (not shown). The spiral portion 10 is configured so that the intake gas (air or a mixture of air, fuel, and EGR gas) flowing into the spiral portion 10 from the port introduction portion 12 is centered on the axis A of the stem 9 of the intake valve 7 in the spiral portion 10. In such a shape, a swirl flow is formed. That is, the spiral portion 10 has a spiral shape centered on the axis A of the stem 9 of the intake valve 7. Accordingly, the intake gas that has flowed into the spiral portion 10 from the port introduction portion 12 swivels around the axis A of the stem 9 of the intake valve 7 within the spiral portion 10, and is positioned below the spiral portion 10 and enters the combustion chamber 4. The gas flows out into the combustion chamber 4 through a region (hereinafter referred to as “outflow region”) 13 of the spiral portion that faces. Further, the port introduction part 12 is connected to the spiral part 10 with a slight offset so as to strengthen the swirl flow of the intake gas generated in the spiral part 10. Further, the port introduction portion 12 is a region in which the flow passage cross-sectional area of the intake gas is reduced in order to increase the flow velocity of the intake gas flowing into the vortex portion 10 and strengthen the swirl flow of the intake gas generated in the vortex portion 10 ( (Hereinafter referred to as “small cross-sectional area”) 14.

  Therefore, the intake gas flowing through the helical intake ports 5 and 6 flows from the inlet end portion 11 into the port introduction portion 12, and the flow velocity thereof is increased through the small cross-sectional area 14 of the port introduction portion 12. Thereafter, the intake gas having a high flow velocity flows into the spiral portion 10, and a strong swirl flow is given to the intake gas within the spiral portion 10. The intake gas in the spiral portion 10 flows out into the combustion chamber 4 through the outflow region 13 of the spiral portion 10 while having a swirl direction velocity component. Therefore, the intake gas in the combustion chamber 4 forms a swirl (swirl flow) in the direction indicated by the arrow B in FIG. As described above, by using the helical intake ports 5 and 6, it is possible to generate the swirl of the intake gas swirling in the direction indicated by the arrow B in FIG. 1 in the combustion chamber 4.

  In the intake device of the present invention, the intake port provided on the upstream side in the swirling direction B of the swirl generated in the combustion chamber 4 of the two intake ports 5 and 6 is provided on the upstream side intake port 5 and the downstream side. When the intake port is referred to as the downstream intake port 6, the sleeve mechanism 20 is provided on the inner wall surface 15 located downstream of the swirl in the swirl direction generated in the combustion chamber 4 in the inner wall surface of the spiral portion 10 of the upstream intake port 5. It is done.

  The sleeve mechanism 20 includes a slide groove 21 provided on the inner wall surface of the upstream side intake port 5, a sleeve 22 disposed on the slide groove, and a drive mechanism (not shown) for driving the sleeve 22. . The sliding groove 20 extends at an angle θ with respect to the circumferential direction of the spiral portion 10, that is, with respect to a plane perpendicular to the axis of the intake valve 7. The cross section of the sliding groove 21 perpendicular to the direction in which the sliding groove 21 extends is substantially semicircular. Further, the sliding groove 21 communicates with a cylindrical through hole provided in the cylinder head 3.

  A hollow cylindrical sleeve 22 having a shape complementary to the sliding groove 21 is disposed on the sliding groove 21, and this sleeve 22 passes through the through hole. FIG. 4 shows the sleeve 22 in detail. 4A is a perspective view of the sleeve 22, and FIG. 4B is a cross-sectional view of the sleeve 22 taken along line IV-IV in FIG. 4A. As shown in FIG. 4B, a flow passage 23 through which intake gas can flow is provided in the sleeve 22, and the tip of the sleeve 22 is oriented at an angle with respect to the axis of the sleeve 22. An outlet 24 is provided. In this embodiment, the outlet 24 is oriented perpendicular to the axis of the sleeve 22.

  The sleeve 22 is connected at its rear end to an intake port 5 and an intake manifold or intake pipe (hereinafter collectively referred to as “intake passage”) communicating with the intake port 5. Therefore, the intake gas flows in from the rear end portion of the sleeve 22, flows from the rear end side toward the front end side through the flow passage 23, and flows out into the intake port through the outflow port 24. The intake gas flowing out from the sleeve 22 into the spiral portion 10 of the intake port is directed in the direction in which the outlet 24 of the sleeve 22 faces.

  Here, in the intake device of the present embodiment, the sleeve 22 can be rotated about the axis of the sleeve 22 on the sliding groove 21, and at the same time, can be slid in the axial direction of the sleeve 22. FIG. 5 and FIG. 6 show how the sleeve 22 rotates and slides. FIG. 5 is a view similar to FIG. 2, and FIG. 6 is a view similar to FIG.

  As the sleeve 22 rotates about its axis, the sleeve 22 rotates (hereinafter referred to as “upward rotation”) so that the direction of the outlet 24 is more upward as indicated by the arrow C in FIG. As shown by the arrow D in FIG. 3, the outlet 24 is rotated so as to be directed downward (hereinafter referred to as “downward rotation”). That is, the sleeve 22 is moved upward from the downward angle at which the outlet 24 is relatively downward as shown in FIG. 3 to the upward angle at which the outlet 24 is relatively upward as shown in FIG. On the contrary, it can be rotated downward from an upward angle to a downward angle.

  When the sleeve 22 slides in the axial direction, does the sleeve 22 move away from the through hole in the sliding groove 21 as indicated by an arrow E in FIG. 2 (hereinafter referred to as “extension movement”)? Or in the sliding groove 21 in a direction approaching the through hole (hereinafter referred to as “retraction movement”). That is, the sleeve 22 is retracted from the extended position in which the outlet 24 is relatively away from the through hole as shown in FIG. 2 to the retracted position in which the outlet 24 is relatively close to the through hole as shown in FIG. On the contrary, it is possible to extend and move from the retracted position to the extended position.

  Such rotation and sliding of the sleeve 22 is performed by a driving mechanism provided at the rear end portion of the sleeve 22. The sliding range and turning range of the sleeve 22 are basically within a range where at least a part of the outlet 24 of the sleeve 22 is always open in the spiral portion 10 of the intake port.

  However, if the outflow port 24 is basically completely drawn into the through hole or is rotated until it faces the sliding groove 21, the outflow of the intake gas from the sleeve 22 is blocked. Is done. That is, the flow rate of the intake gas flowing out from the sleeve 22 to the intake port, that is, the combustion chamber 4 is determined according to the area where the outlet 24 is open to the intake port without facing the through hole or the sliding groove 21. When this area is zero, the outflow of intake gas from the sleeve 22 is blocked. For this reason, the sleeve 22 can be used as a flow rate adjusting means. Therefore, in this embodiment, the sleeve 22 can be slid / rotated to a range in which the outflow of intake gas from the sleeve 22 is blocked in addition to the above-described sliding / rotation range.

  As the sleeve 22 slides and rotates in this manner, the angle at which the intake gas flows out from the outlet 24 of the sleeve 22 into the spiral portion 10 of the intake port (hereinafter referred to as “outflow angle”), and the outlet The position at which the intake gas flows out from 24 into the spiral portion 10 (hereinafter referred to as “outflow position”) changes. Hereinafter, the relationship between the outflow angle and the outflow position, the swirl ratio of the swirl generated in the intake gas in the combustion chamber 4 and the flow rate of the intake gas flowing out into the combustion chamber 4 will be described. In the present specification, “flow rate” means the flow rate of the intake gas flowing into the combustion chamber 4 when the differential pressure between the upstream portion of the intake passage and the combustion chamber 4 is constant.

  FIG. 7 is a diagram showing the relationship between the swirl ratio, the flow rate of the intake gas, and the outflow angle. The outflow angle in the figure means an angle rotated upward from the downward angle. The smaller the outflow angle (that is, located on the left side in the figure), the smaller the downward angle, that is, the right side in the figure. It is upwards. As can be seen from the figure, the flow rate of the intake gas is almost constant with respect to the outflow angle. This is because even if the outflow angle of the sleeve 22 is changed, the sleeve 22 protrudes from the inner wall surface of the spiral portion 10 in the same manner, so that the flow resistance of the intake gas hardly changes.

  On the other hand, regarding the swirl ratio of the swirl generated in the intake gas in the combustion chamber 4, when the outflow angle is reduced, that is, when the outflow direction of the intake gas is changed downward, the swirl ratio is increased, and when the outflow angle is increased, that is, the intake gas. The swirl ratio is reduced when the outflow direction is changed upward. This is because the intake gas flowing out from the outlet 24 of the sleeve 22 easily flows out into the combustion chamber 4 while maintaining the velocity component in the swirl swirl direction when the outflow direction of the intake gas is changed downward. When the gas outflow direction is changed upward, the intake gas flowing out from the outlet 24 of the sleeve 22 interferes with the swirl flow of the intake gas in the swirl portion 10 and the velocity component in the swirl swirl direction becomes small. This is because it will be leaked into. In particular, when the intake gas flows along the upper surface of the valve body 8 of the intake valve 7, the intake gas easily flows out into the combustion chamber 4, and therefore, the outflow direction of the intake gas from the sleeve 22 depends on the valve body 8 of the intake valve 7. When the direction is along the upper surface, the swirl generated in the intake gas in the combustion chamber 4 can be strengthened.

  Therefore, according to the present invention, the swirl of the swirl generated in the intake gas in the combustion chamber 4 can be adjusted without changing the flow rate of the intake gas flowing out into the combustion chamber 4 by adjusting the outflow angle of the intake gas from the sleeve 22. The strength can be changed.

  FIG. 8 shows the swirl ratio of the swirl generated in the intake gas in the combustion chamber 4 and the intake air flowing into the combustion chamber 4 when the opening degree of the flow rate adjusting valve 33 described later is adjusted when the slide position of the sleeve 22 is different. It is a figure which shows the relationship (henceforth "a swirl ratio and flow volume relationship") with the flow volume of gas. In the figure, line s indicates the swirl ratio / flow rate relationship when the sleeve is in the extended position, and line t indicates the swirl ratio / flow rate relationship when the sleeve is in the retracted position. As can be seen from the figure, when the flow rate of the intake gas is constant, the swirl ratio is larger when the sleeve is in the retracted position than when the sleeve is in the extended position, and when the swirl ratio is constant, the sleeve is The intake gas flow rate is higher in the retracted position than in the extended position.

  There are two possible reasons why the swirl ratio / flow rate relationship is as follows. First, for the first reason, when the sleeve 22 is in the retracted position, the intake gas flowing out from the outlet 24 of the sleeve 22 flows along the inner wall surface of the spiral portion 10. Therefore, since this intake gas flows out into the combustion chamber 4 while strengthening the swirl flow in the spiral portion 10, the swirl generated in the intake gas in the combustion chamber 4 becomes stronger. When the sleeve 22 is in an intermediate position between the retracted position and the extended position, the intake gas flowing out from the outlet 24 of the sleeve 22 is likely to directly contact the valve body 8 or the stem 9 of the intake valve 7. The speed is reduced before it flows into 4. For this reason, the swirl generated in the intake gas in the combustion chamber 4 is weaker than when the sleeve 22 is in the retracted position. When the sleeve 22 is in the extended position, the intake gas flowing out from the outlet 24 of the sleeve 22 is directed in the direction opposite to the swirling flow of the intake gas in the spiral portion 10 in the spiral portion 10. Flows out into the combustion chamber 4 while weakening the swirl flow. For this reason, the swirl generated in the intake gas in the combustion chamber 4 is weaker than that in the case where the sleeve 22 is in the intermediate position. For this reason, when the sleeve 22 is in the retracted position, the swirl is strong, and as the sleeve 22 moves to the extended position, the swirl becomes weak.

  The second reason is that as the sleeve 22 slides from the retracted position toward the extended position, the portion of the sleeve 22 protruding from the inner wall surface of the spiral portion 10 increases, and the intake gas in the spiral portion 10 by the sleeve 22 increases. The flow resistance to the swirling flow increases. Therefore, when the sleeve 22 is on the extended position side, the intake gas is less likely to flow through the spiral portion 10, the flow rate of the intake gas flowing out into the combustion chamber 4 is reduced, and the swirl ratio of the intake gas is reduced. As a result, the swirl ratio / flow rate relationship as shown in FIG. 8 is obtained.

  By the way, as described above, the sleeve 22 protrudes inward from the inner wall surface of the spiral portion 10. Therefore, the sleeve 22 is more or less resistant to the spiral flow of the intake gas in the spiral portion 10. On the other hand, when the intake ports 5 and 6 are arranged with respect to the combustion chamber 4 as shown in FIG. 1, that is, the downstream intake port 6 flows from the port introduction portion 12 to the spiral portion rather than the upstream intake port 5. When the intake gas to be directed more in the tangential direction of the combustion chamber 4, the intake gas flowing out from the spiral portion 10 of the upstream intake port 5 into the combustion chamber 4 flows out of the spiral portion 10 of the downstream intake port 6. The intake gas has a larger swirl direction velocity component. Therefore, the degree to which the swirl is strengthened by the downstream side intake port 6 is larger than the degree to which the swirl generated in the intake gas in the combustion chamber 4 is strengthened by the upstream side intake port 5.

  Here, in this embodiment, the sleeve mechanism 20 is provided not in the spiral portion 10 of the downstream intake port 6 but in the spiral portion of the upstream intake port 5. That is, the sleeve mechanism 20 is provided in the spiral portion 10 of the intake port that is difficult to strengthen the swirl generated in the intake gas of the combustion chamber 4. For this reason, although the sleeve mechanism 20 has a flow resistance of the intake gas, the influence on the swirl is small.

  Further, the intake gas that has flowed into the spiral portion 10 from the port introduction portion 12 flows into the combustion chamber 4 while swirling within the spiral portion 10. The outflow amount of the intake gas from the vortex portion 10 into the combustion chamber 4 is generally from the portion of the vortex portion 10 communicating with the port introduction portion 12 (hereinafter referred to as “vortex start portion”) to the vortex portion 10. Of these, it decreases as it goes to a portion located in the swirl direction downstream side of the swirl flow in the swirl portion 10 (hereinafter referred to as “spiral end portion”). For this reason, it is less likely that the provision of the sleeve mechanism at the end of the spiral than the start of the spiral is an obstacle to the flow of the intake gas. Here, in the present embodiment, the sleeve mechanism 20 has an inner wall surface located downstream of the swirl in the swirling direction of the inner wall surface of the spiral portion 10 of the upstream intake port 5, that is, the spiral portion 10 of the upstream intake port 5. Since it is provided at the end of the spiral, the sleeve mechanism 20 can be provided without substantially reducing the flow rate of the intake gas.

  In this embodiment, the sleeve mechanism 20 is provided in the upstream intake port 5, but the sleeve mechanism 20 is not limited to the upstream intake port, and a swirl generated in the combustion chamber 4 among the plurality of intake ports is not provided. It is preferable to provide the sleeve mechanism 20 at the intake port having the lowest degree of strengthening.

  In the intake device of the present invention, the sleeve mechanism 20 can be installed simply by providing the through hole and the sliding groove 21 in the cylinder head 3 in the vicinity of the intake port. Therefore, it is necessary to change the design of the existing intake port. There is little, and its design is very easy. It is also possible to add a sleeve mechanism 20 to the intake port of an internal combustion engine that has already been used.

  FIG. 9 is a view schematically showing an intake passage communicating with one combustion chamber 4. As shown in FIG. 9, the intake passage has an intake manifold 30 communicating with intake ports 5 and 6, and the intake manifold 30 is communicated with an intake pipe (not shown) having a throttle valve. The intake manifold 30 branches into two branch manifolds 31 and 32, and communicates with the upstream intake port 5 and the downstream intake port 6, respectively. A flow rate adjustment valve (swirl control valve) 33 for adjusting the flow rate of the intake gas flowing through the upstream branch manifold 31 is provided in the upstream branch manifold 31 communicating with the upstream intake port 6.

  Further, a bypass passage 34 having a smaller channel cross-sectional area than the intake ports 5 and 6 and the branch manifolds 31 and 32 branches from the intake manifold 30 upstream of the branching portion. The bypass passage 34 includes the sleeve 22 described above, so that the intake gas flowing through the bypass passage 34 flows out from the outlet 24 of the sleeve 22 into the intake port.

  For this reason, in the present embodiment, when the flow rate adjustment valve 33 is opened, most of the intake gas flows through the upstream branch manifold 31 and the downstream branch manifold 32, so that the intake gas mostly passes through the bypass passage 34. Therefore, the flow rate of the intake gas flowing out from the outlet 24 of the sleeve 22 is small. Conversely, when the flow rate adjustment valve 33 is closed, the intake gas cannot flow through the upstream branch manifold 31, and therefore the pressure of the intake gas in the intake manifold 30 upstream of the flow rate adjustment valve 33. Becomes higher. For this reason, the intake gas flows through the bypass passage 34. Therefore, the flow rate of the intake gas flowing through the bypass passage 34 changes according to the opening degree of the flow rate adjustment valve 33.

  FIG. 10 shows the relationship between the swirl ratio of the swirl generated in the intake gas in the combustion chamber, which can be adjusted by the intake device of the present embodiment, and the flow rate of the intake gas flowing into the combustion chamber 4 (swir ratio / flow rate relationship). . A broken line x in the figure indicates a swirl ratio / flow rate relationship according to a change in the opening degree of the flow rate adjustment valve 33 when the sleeve mechanism 20 is not provided. When the opening degree of the flow rate adjustment valve 33 is large, When the swirl ratio is small and the flow rate is large, and when the opening degree of the flow rate adjustment valve 33 is small, the swirl ratio is large and the flow rate is small.

  Here, if the outflow angle of the outlet 24 of the sleeve 22 is changed as described above, the swirl ratio can be changed while the flow rate of the intake gas is maintained substantially constant. The broken line x in the figure represents the swirl ratio / flow rate relationship when the sleeve mechanism 20 is not provided, that is, when the intake gas does not flow out from the outlet 24 of the sleeve 22. Then, the swirl ratio can be increased while keeping the flow rate constant from the broken line x by allowing the intake gas to flow out from the outlet 24 of the sleeve 22 and changing the outflow angle. Furthermore, the swirl ratio can be changed by changing the outflow position. Thus, the swirl ratio / flow rate relationship that can be taken by changing the outflow angle and outflow position is a region indicated by a vertical line in FIG. That is, by arbitrarily changing the outflow angle and the outflow position, the relationship between the swirl ratio and the flow rate can be changed within the vertical line region in FIG.

  The solid line z in FIG. 10 is the case where the swirl of the intake gas can be strengthened most effectively, that is, the outflow angle from the outlet 24 is an angle along the valve face, and the outflow position of the outlet 24 is the retracted position. The swirl ratio / flow rate relationship in the case where the intake gas flowing out from the outlet 24 flows along the inner wall surface of the spiral portion 10 is shown.

  As can be seen from FIG. 10, when the flow rate of the intake gas is large, that is, when the opening degree of the flow rate adjustment valve 33 is large, the flow rate of the intake gas flowing out from the outlet 24 of the sleeve 22 is small. Even if the outflow angle or the outflow position of the intake gas from the outflow port 24 is changed, the swirl ratio does not change greatly. When the flow rate of the intake gas is small, that is, when the opening of the flow rate adjustment valve 33 is small, the flow rate of the intake gas flowing out from the outlet port 24 of the sleeve 22 is large. If the outflow angle or the outflow position is changed, the swirl ratio changes greatly.

  On the other hand, when the sleeve 22 is slid while the outlet 24 of the sleeve 22 is directed toward the sliding groove 21, the portion where the sleeve 22 protrudes from the inner wall surface of the spiral portion 10 changes, that is, within the spiral portion 10. The flow resistance to the intake gas changes, and the relationship between the swirl ratio and the flow rate changes. As described above, the relationship between the swirl ratio and the flow rate, which is changed by changing the slide position of the sleeve 22 in a state where the intake gas does not flow out from the outlet 24 of the sleeve 22, is shown by hatching in FIG. The swirl ratio / flow rate relationship in the case where the sleeve 22 is in a position that hardly protrudes from the through hole is the same as the swirl ratio / flow rate relationship in the case where the sleeve mechanism 20 is not provided. The flow rate relationship is shown. On the other hand, when the sleeve 22 is in the extended position, the swirl ratio is smaller and the flow rate is lower than when the sleeve 22 is in the retracted position. Therefore, when the protrusion amount of the sleeve 22 from the through hole is maximized, the swirl ratio / flow rate relationship as shown by the solid line y in FIG. 10 is obtained. That is, the hatched area in FIG. 10 shows the relationship between the swirl ratio and the flow rate that can be taken when the amount of protrusion of the sleeve 22 from the through hole is changed without flowing the intake gas from the sleeve 22 into the intake port 5. Yes.

  That is, according to this embodiment, the outflow angle of the intake gas from the outflow port 24 of the sleeve 22, the outflow position, the outflow / blocking of the intake gas from the outflow port 24 of the sleeve 22, and the opening degree of the flow rate adjustment valve 33 are set. By adjusting, the relationship between the swirl ratio of the swirl generated in the intake gas in the combustion chamber 4 and the flow rate of the intake gas flowing out into the combustion chamber 4 can be changed in the vertical line region and the hatched region in FIG. .

  In the above embodiment, the outflow / outlet of the intake gas from the outflow port 24 of the sleeve 22 is performed by directing the outflow port 24 of the sleeve 22 toward the sliding groove 21. A flow rate adjustment valve for adjusting the flow rate of the intake gas flowing through the passage may be provided, and the flow rate adjustment valve may be opened and closed to allow the intake gas to flow out and shut off from the outlet 24 of the sleeve 22.

  In the present invention, the helical intake port is used as the intake port. However, any type of intake port may be used as long as swirl can be generated in the intake gas in the combustion chamber without using the sleeve mechanism. Furthermore, the sleeve mechanism of the present invention may be applied to an intake port that cannot generate a swirl in the intake gas in the combustion chamber.

It is a bottom view of the cylinder head corresponding to each combustion chamber. FIG. 2 is a cross-sectional view around an intake port and an intake valve taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view around an intake port and an intake valve along line III-III in FIG. It is a figure which shows a sleeve. FIG. 3 is a view similar to FIG. 2 for explaining rotation / sliding of a sleeve 22. FIG. 4 is a view similar to FIG. 3 for explaining rotation / sliding of a sleeve 22. It is the figure which showed the relationship between a swirl ratio, the flow volume of intake gas, and an outflow angle. It is a figure which shows the relationship between the swirl ratio and flow volume which change according to the sliding position of a sleeve. It is the figure which showed typically the intake passage connected to one combustion chamber. The relationship between the swirl ratio and flow volume which can be adjusted with the intake device of this embodiment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder block 3 ... Cylinder head 4 ... Combustion chamber 5, 6 ... Intake port 7 ... Intake valve 10 ... Swivel part 20 ... Sleeve mechanism 21 ... Sliding groove 22 ... Sleeve 24 ... Outlet 33 ... Flow rate adjustment valve

Claims (5)

In an intake device for an internal combustion engine comprising an intake port that communicates with a combustion chamber and a bypass passage that communicates with the intake port in the vicinity of the combustion chamber.
In the region where the bypass passage communicates with the intake port, at least one of the direction in which the intake gas flows out from the bypass passage into the intake port and the position where the intake gas flows out into the intake port from the bypass passage are changed. An intake device for an internal combustion engine comprising a direction / position changing means for changing the strength of a swirl generated in the intake gas of the engine.   The intake device for an internal combustion engine according to claim 1, further comprising a flow rate adjusting means for adjusting a flow rate of the intake gas flowing out from the bypass passage into the combustion chamber.   3. A plurality of intake ports are provided per cylinder, and the bypass passage and the direction / position changing means are provided only in the intake port located upstream in the swirl turning direction among the plurality of intake ports arranged side by side. Intake device for internal combustion engine.   The internal combustion engine according to any one of claims 1 to 3, wherein a plurality of intake ports are provided per cylinder, and a flow rate adjusting valve for adjusting a flow rate of intake gas flowing through the intake port is provided in one intake port. Engine intake system.   The tip of the bypass passage is provided with a sleeve partially embedded in the inner wall surface of the intake port as the direction / position changing means, and the sleeve is directed at an angle with respect to its axis. 2. A gas outlet and a relative movement with respect to the intake port, wherein at least one of a rotational movement around the axis of the sleeve and a sliding movement in the axial direction of the sleeve is possible. The intake device for an internal combustion engine according to any one of -4.

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