JP4375060B2 - Intake device for internal combustion engine - Google Patents

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 cylinder bore (combustion chamber) to promote the mixing of air and fuel in the cylinder bore, thereby achieving efficient combustion in the cylinder bore. There is something that is made to do. In particular, in the diesel engine, by strengthening the swirl, less operation of NO _X emissions are believed to be possible with the smoke in the exhaust gas can be significantly reduced.

  As described above, when swirl is generated in the intake gas supplied into the cylinder bore, in general, the shape of the intake port is made to be a shape in which swirl is easily generated, or either one of the two intake ports leading to one cylinder bore is used. The use of a swirl control valve that opens and closes the intake port is adopted.

  However, when such a configuration is adopted, in order to generate a strong swirl, it is necessary to increase the flow rate of the intake gas in the intake port or to cause interference between the intake ports when there are multiple intake ports. It is necessary to avoid this, and for that purpose, it is necessary to provide an intake throttle in the intake port or the like. However, if an intake throttle is provided, intake resistance will occur, leading to a reduction in the flow rate of intake gas flowing into the cylinder bore and a deterioration in fuel consumption. That is, it was difficult to achieve both a high swirl ratio and a high flow rate.

  Here, in the intake device described in Patent Document 1, a semicircular arc-shaped swirl guide that protrudes downward from the valve guide is provided around the intake valve, and the outflow direction of the intake gas from the intake port into the cylinder head is constant. Limiting the direction, a swirl of intake gas is generated in the cylinder bore. Therefore, according to the apparatus described in Patent Document 1, by providing the swirl guide in this way, it is possible to generate a swirl without providing an intake throttle for increasing the flow velocity at the intake port or the like.

Japanese Utility Model Publication No. 60-159808 Japanese Utility Model Publication No. 2-63034 JP-A 61-16223 JP 63-162927 A Japanese Utility Model Publication No. 60-1926 JP 62-131961 A

  However, in the intake device described in Patent Document 1, not only the surface of the swirl guide that faces the intake valve, but also the opposite surface (hereinafter referred to as “rear surface”) extends perpendicularly to the lower surface of the cylinder head. . That is, the back surface of the swirl guide is positioned perpendicular to the swirling direction of the swirl of the intake gas in the cylinder bore. It will weaken. Therefore, in the intake device described in Patent Document 1, since the speed component in the swirl direction of the intake gas is weakened by the swirl guide, a strong swirl cannot be generated, and both a high swirl ratio and a high flow rate are achieved. Have difficulty.

  Accordingly, an object of the present invention is to provide an intake device capable of generating a strong swirl while suppressing a decrease in the flow rate of intake gas.

In order to solve the above problems, in the first invention, an intake port provided in a cylinder head and communicating with a cylinder bore, an intake valve that opens and closes an outlet opening of the intake port, and the cylinder around the outlet opening of the intake port A restricting wall that restrains the intake gas from flowing out of the intake port into the cylinder bore in a direction opposite to the swirling direction of the intake gas in the cylinder bore. in an intake device for an internal combustion engine having the above-mentioned protruding portion has a slope on the side opposite to the turning direction of the intake gas in the cylinder bore to the upper Symbol regulation wall, the slope over the slope in the radially inner side of the cylinder bore It is formed to guide the passing intake gas so as to turn on the outside in the radial direction of the cylinder bore .
According to the first aspect of the invention, since the protrusion has the slope, the intake gas swirling in the cylinder bore flows without being weakened in the swirl direction speed component when passing under the protrusion. That is, by providing a slope on the side opposite to the turning direction of the protruding portion, it is possible to reduce the flow resistance due to the restriction wall against the intake gas swirling in the cylinder bore. Therefore, the swirl generated in the intake gas in the cylinder bore is strong. Further, by providing the slope, the flow rate of the intake gas flowing into the cylinder bore does not decrease.

In a second invention, in the first invention, the restriction wall protrudes from the surface of the cylinder head higher than a maximum valve lift amount of the intake valve.
According to the second aspect of the present invention, the intake gas flowing out from the intake port into the cylinder bore is reliably prevented from moving in the anti-turning direction, and the intake gas in the cylinder bore flowing along the slope is transferred from the intake port into the cylinder bore. Interference with the outflowing intake gas is suppressed.

In a third invention, in the first or second invention, a plurality of the intake ports are provided per cylinder, and the protrusions are provided around the outlet openings of the intake ports.
According to the third invention, since the protrusion is provided around each outlet opening of each intake port, it flows out from the intake port located on the upstream side in the turning direction among the adjacent intake ports in the turning direction. It is suppressed that the intake gas interferes with the intake gas flowing out from the intake port located downstream in the turning direction.

According to a fourth invention, in the third invention, two intake ports adjacent to each other are provided per cylinder, and in the downstream intake port located on the downstream side in the turning direction of these intake ports, in the tangential direction of the cylinder bore and A downstream intake port sub-passage for allowing intake gas to flow into the cylinder bore along the valve face of the intake valve is provided.
According to the fourth aspect of the invention, since the intake gas can flow out from the downstream intake port sub-passage in the tangential direction of the cylinder bore, the swirl is strengthened by flowing the intake gas from the downstream intake port sub-passage into the cylinder bore. be able to.

  In the fifth invention, in the third or fourth invention, two intake ports adjacent to each other are provided, and the intake air in the cylinder bore is provided in the upstream intake port located upstream in the turning direction among these intake ports. An upstream intake port sub-passage is provided for flowing the intake gas into the cylinder bore in a direction substantially perpendicular to the gas swirl direction and along the valve face of the intake valve.

According to a sixth aspect, in the fourth or fifth aspect, the sub passage is configured to be openable and closable based on an engine operating state.
According to the sixth aspect, the strength of the swirl generated in the intake gas in the cylinder bore can be changed according to the engine operating state.

  According to the present invention, the provision of the slope makes the swirl generated in the intake gas in the cylinder bore strong, and the provision of the slope does not reduce the flow rate of the intake gas flowing into the cylinder bore. A strong swirl can be generated while suppressing a decrease in the flow rate.

  Hereinafter, the present invention will be described in detail with reference to the drawings. First, an intake device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a bottom view of a cylinder head, but an intake valve and an exhaust valve are omitted. FIG. 2 is a cross-sectional view of the intake port and the vicinity of the intake valve taken along line II-II in FIG.

  As shown in FIGS. 1 and 2, 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 4 at predetermined intervals. A piston (not shown) reciprocates in each cylinder bore 4, and a combustion chamber is defined between the cylinder bore 4 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.

  Each cylinder bore 4 communicates with two intake ports 5 and 6 and two exhaust ports (not shown). The intake ports 5 and 6 and the exhaust port are provided in the cylinder head 3. The intake ports 5 and 6 are provided on the upper surface of the cylinder bore 4 and communicate with the cylinder bore 4 through outlet openings 7 and 8 that are open to the cylinder bore 4, respectively, and the exhaust port is provided on the upper surface of the cylinder bore 4 and The cylinder bore 4 communicates with inlet openings 9 and 10 that are open to the cylinder bore 4.

  The outlet openings 7 and 8 of the intake ports 5 and 6 are opened and closed by the intake valve 11, whereby the intake ports 5 and 6 and the cylinder bore 4 are fluidly connected or disconnected. Each intake valve 11 has a valve body 12 that actually acts as a valve and a stem 13 connected to the valve body 12, and reciprocates along the axis of the stem 13. Similarly, the inlet ports 9 and 10 of the exhaust port are opened and closed by an exhaust valve, whereby the exhaust port and the cylinder bore 4 are fluidly connected or disconnected.

  A swirl flow (swirl) of intake gas along the outer peripheral wall of the cylinder bore 4 is generated in the cylinder bore 4 in the direction of arrow A (counterclockwise) in FIG. Therefore, the counterclockwise direction in FIG. 1 around the axis α of the cylinder bore 4 is referred to as the turning direction, and the clockwise direction is referred to as the counter-turning direction. That is, the turning direction means one of the circumferential directions of the cylinder bore 4, and the counter-turning direction means a direction opposite to the one of the circumferential directions of the cylinder bore 4.

  In the present embodiment, protrusions 14 and 15 are provided around the outlet openings 7 and 8 of the intake ports 5 and 6, respectively. Hereinafter, only the protrusion 14 provided around the outlet opening 7 of the downstream intake port 5 located on the downstream side in the turning direction of the two intake ports 5 and 6 will be described. However, the upstream intake air located on the upstream side in the turning direction will be described. The protrusion 15 provided around the outlet opening 8 of the port 6 has a similar shape and performs a similar function.

  The protruding portion 14 protrudes downward from the cylinder head 3 in the axial direction of the intake valve 11. As shown in FIG. 2, the protruding portion 14 is formed separately from the cylinder head 3 in this embodiment, but may be formed integrally with the cylinder head 3. Further, the protruding portion 14 includes a restriction wall 16 located on the side facing the outlet opening 7 and a slope 17 located on the side opposite to the turning direction of the restriction wall 16.

  The restriction wall 16 of the protrusion 14 is located around the outlet opening 7 and in the counter-rotating direction of the outlet opening 7 and extends in a semicircular arc shape. More specifically, the regulating wall 16 is in the vicinity of the outer peripheral edge of the outlet opening 7 and is perpendicular to the tangential direction of the cylinder bore at the center of the outlet opening 7 (in this embodiment, the cylinder bore is a perfect circle, It is located in the anti-turning direction rather than a straight line (broken line B in FIG. 1) extending through the center of the outlet opening 7 in the same direction as the cylinder bore radial direction). The surface of the restriction wall 16 facing the outlet opening 7 extends in parallel with the axis β of the intake valve 11, that is, substantially perpendicular to the lower surface of the cylinder head 3. In this embodiment, the height of the restriction wall 16 from the lower surface of the cylinder head 3 in the axial direction of the intake valve 11 is the lift amount when the lift of the intake valve 11 is maximum (hereinafter referred to as “maximum lift amount”). Higher than

  The restriction wall 16 formed in this way suppresses the intake gas from flowing out from the intake port into the cylinder bore 4 in the anti-turning direction. Therefore, since the intake gas flows out from the outlet opening 7 of the intake port 5 in the turning direction due to the presence of the restriction wall 16, the swirl of the intake gas generated in the cylinder bore 4 becomes strong.

  Note that the height of the restriction wall 16 may be lower than the maximum lift amount as long as the intake gas can be prevented from flowing into the cylinder bore 4 in the anti-turning direction from the intake port. Further, the regulation wall 16 does not have to extend over the entire region located in the vicinity of the periphery of the outlet opening 7 and in the anti-turning direction with respect to the outlet opening 7, and a part of such a region is shorter than a semicircular arc. It may extend.

  On the other hand, the slope 17 of the protrusion 14 is formed so that its height gradually decreases from the restriction wall 16 in the counter-turning direction. The slope 17 is formed so as to guide the intake gas swirling in the cylinder bore 4 so as to flow along the outer wall surface of the cylinder bore. That is, the slope 17 is formed so as to guide the intake gas in the direction indicated by the arrow on the slope 17 in FIG.

  Here, if the back surface of the regulating wall extends substantially perpendicularly to the bottom surface of the cylinder head 3 without providing the slope 17, the swirl of the intake gas generated in the cylinder bore is restricted by the regulating wall. Hit the back of the. For this reason, the swirl direction velocity component of the swirl of the intake gas is reduced on the back surface of the restriction wall, and is converted into a velocity component directed downward. That is, the restriction wall becomes a resistance against the swirl of the intake gas. Therefore, when the slope 17 is not provided, the swirl of the intake gas is weakened due to the presence of the restriction wall.

  On the other hand, in the present embodiment, since the slope 17 is provided on the back surface of the restriction wall 16, the swirl direction velocity component of the swirl of the intake gas is hardly reduced and is not easily converted into a downward velocity component. For this reason, the restriction wall 16 does not have a large resistance to the swirl of the intake gas, and therefore, the presence of the restriction wall 16 prevents the intake gas swirl from being weakened.

  In particular, in the present embodiment, the slope 17 protrudes in the vicinity of the intake valve 11 to a height higher than the height of the restriction wall, that is, the maximum lift amount of the intake valve 11. Therefore, the intake gas in the cylinder bore 4 that flows through the slope 17 flows on the lower surface of the valve body 12 of the intake valve 11. Accordingly, the intake gas in the cylinder bore 4 hardly interferes with the intake gas flowing out from the intake port 5 through the outlet opening 7 when passing through the region below the outlet opening 7. The intake gas that has flowed out of the intake port 5 having a large swirl direction velocity component in the region on the swirl direction side from the outlet opening 7 through the outlet opening 7 and the inside of the cylinder bore 4 that has passed through the region below the outlet opening 7 The intake gas merges and the swirl in the cylinder bore 4 is strengthened.

  Further, the slope 17 guides the intake gas swirling in the cylinder bore 4 so as to flow along the outer wall surface of the cylinder bore 4. That is, not only the intake gas passing on the slope 17 on the radially outer side of the cylinder bore 4 but also the intake gas passing on the slope 17 on the radially inner side of the cylinder bore 4 is guided along the outer wall surface of the cylinder bore 4. For this reason, the flow of the intake gas along the outer wall surface of the cylinder bore 4 is strengthened, so that the swirl of the intake gas in the cylinder bore 4 is strengthened.

  Therefore, according to the present embodiment, by providing the slope 17 in the protrusion 14, the resistance of the intake gas in the cylinder bore 4 to the swirl is reduced, and the flow of the intake gas along the outer wall surface of the cylinder bore 4 is strengthened. Therefore, the swirl of the intake gas in the cylinder bore 4 is strengthened. On the other hand, the provision of the slope 17 in the projecting portion 14 does not become an intake resistance, so the flow rate of the intake gas flowing out into the cylinder bore 4 does not decrease. Therefore, according to the present embodiment, the swirl ratio of the intake gas in the cylinder bore 4 can be increased while maintaining the flow rate of the intake gas without decreasing.

  By the way, when the protrusions 14 and 15 are not provided, the intake gas flows out from the outlet openings 7 and 8 of the intake ports 5 and 6 in the radial direction over the entire circumference. When two intake ports are provided for one cylinder as in the present embodiment, the intake gas flowing out from the outlet opening 7 of the downstream intake port 5 in the anti-turning direction and the outlet opening 8 of the upstream intake port 6 are turned. As a result, the swirl of the intake gas in the cylinder bore 4 becomes weak. On the other hand, in this embodiment, since the intake portion suppresses the intake gas from flowing out from the outlet opening 7 of the downstream intake port 5 in the anti-turning direction by the protrusion 14, the interference of the intake gas as described above is suppressed. The swirl of the intake gas is prevented from being weakened.

  Further, the intake gas that has flowed out in the turning direction from the outlet opening 8 of the upstream intake port 6 reaches the vicinity of the outlet opening 7 of the downstream intake port 5 immediately after the outflow. Here, as described above, in the present embodiment, since the slope 17 is provided on the protruding portion 14 provided around the outlet opening 7 of the downstream intake port 5, the turning direction from the outlet opening 8 of the upstream intake port 6. The intake gas that has flowed out into the cylinder bore can flow in the cylinder bore in the turning direction without receiving a large resistance.

  In this embodiment, a tangential port that does not generate a swirl of intake gas in the intake port is used. However, a swirl of intake gas is generated in the intake port, particularly in the spiral portion located at the tip of the intake port. A helical port may be used. However, when a helical port is used as the intake port, the intake gas flows out from the spiral portion into the cylinder bore in the tangential direction of the outlet opening. Therefore, in this case, the protruding portion is arranged at a position different from that in the above embodiment. That is, a protrusion is provided in a region where the intake gas flowing out from the outlet opening has an anti-swirl direction velocity component in a region around the outlet opening of the intake port. Thereby, even if it is a case where a helical port is used for an intake port, it is suppressed that an intake gas flows out in an anti-turning direction from an exit opening.

  Moreover, in the said embodiment, although two intake ports are provided, the number of intake ports may not be two, for example, you may have one or three intake ports. Even in such a case, the protrusions are respectively attached at similar positions around the outlet opening of each intake port.

  Next, an intake device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a view similar to FIG. 1 and is a bottom view of the cylinder head. 4 is a view similar to FIG. 2, and is a cross-sectional view around the intake port and the intake valve along line IV-IV in FIG. FIG. 5 is a schematic diagram of an intake port and an intake manifold. The configuration of the intake device of the second embodiment is basically the same as the configuration of the first embodiment shown in FIGS. 1 and 2, and the same reference numerals are given to the same components.

  In the intake device of the second embodiment, as shown in FIG. 5, sub passages 20 and 21 are provided in parallel to the intake ports 5 and 6, respectively. One end of a sub-passage (hereinafter referred to as “downstream sub-passage”) 20 for the downstream intake port 5 is connected to an upstream portion of the downstream intake port 5 or an intake manifold that communicates with the downstream intake port 5 (hereinafter collectively referred to as “collection manifold”). (Referred to as “downstream intake passage”). The cross-sectional area of the downstream sub-passage 20 is smaller than the cross-sectional area of the downstream intake port 5. The other end portion (hereinafter referred to as “exit end portion”) 22 of the downstream sub-passage 20 is close to the outer peripheral wall of the cylinder bore 4 in the inner wall surface of the downstream intake port 5 in the vicinity of the outlet opening 7 of the downstream intake port 5. Projects from the wall. The outlet end 22 of the downstream sub-passage 20 flows the intake gas flowing through the downstream sub-passage 20 into the cylinder bore 4 through the outlet opening 7 in the tangential direction of the cylinder bore 4 and along the valve face of the intake valve 11. It is facing the direction to make it.

  Therefore, the intake gas flowing through the downstream sub-passage 20 flows out in the tangential direction of the cylinder bore 4 from the region close to the outer peripheral wall of the cylinder bore 4 in the outlet opening 7 as indicated by the arrow B in FIG. Therefore, the intake gas flowing out from the outlet end 22 of the downstream sub-passage 20 flows out in the same direction as the swirling direction of the swirl of the intake gas in the cylinder bore 4, so that the swirl of the intake gas is caused by this intake gas. Strengthened. Further, the intake gas flows out into the cylinder bore 4 along the valve face of the intake valve 11 as indicated by an arrow B in FIG. Accordingly, the intake gas flowing out from the outlet end 22 of the downstream sub-passage 20 flows to the cylinder bore 4 with little resistance from the valve body 12 of the intake valve 11, effectively increasing the swirl of the intake gas in the cylinder bore 4. be able to.

  On the other hand, one end of a sub-passage (hereinafter referred to as “upstream sub-passage”) 21 for the upstream intake port 6 is connected to an upstream portion of the upstream intake port 6 or an intake manifold (hereinafter referred to as these). Are collectively referred to as an “upstream intake passage”. The cross-sectional area of the upstream sub-passage 21 is smaller than the cross-sectional area of the upstream intake port 6. The upstream intake passage is provided with an upstream intake passage flow regulating valve (swirl control valve) 24 that opens and closes the upstream intake passage to control the flow of intake gas in the upstream intake passage. The portion communicates with the upstream intake passage at a position upstream of the position where the upstream intake passage flow rate adjusting valve 24 is provided. The other end portion (hereinafter referred to as “exit end portion”) 23 of the upstream sub-passage 21 is close to the outer peripheral wall of the cylinder bore 4 in the inner wall surface of the upstream intake port 6 in the vicinity of the outlet opening 8 of the upstream intake port 6. Projects from the wall. The outlet end portion 23 of the upstream sub-passage 21 passes through the upstream sub-passage 21 through the outlet opening 8 in a direction substantially perpendicular to the swirling direction of the intake gas in the cylinder bore 4 and along the valve face of the intake valve 11. The direction of the intake gas flowing in the direction toward the cylinder bore 4 is directed. The upstream sub-passage 21 is provided with an upstream sub-passage flow adjustment valve 25, and the upstream sub-passage flow adjustment valve 25 adjusts the flow rate of the intake gas flowing through the upstream sub-passage 21.

  As indicated by an arrow C in FIG. 3, the intake gas flowing through the upstream sub-passage 21 is substantially in the swirling direction of the intake gas in the cylinder bore 4 from the region near the center of the cylinder bore 4 in the outlet opening 8. It flows out in the vertical direction. Therefore, the intake gas flowing out from the outlet end 23 of the upstream sub-passage 21 interferes with the intake gas swirl in the cylinder bore 4 and weakens the intake gas swirl in the cylinder bore 4. Further, since the intake gas flows out into the cylinder bore 4 along the valve face of the intake valve 11, the intake body 11 hardly receives resistance by the valve body 12 of the intake valve 11, and thus effectively swirls the intake gas in the cylinder bore 4. Can be weakened.

  The upstream intake passage flow rate adjusting valve 24 adjusts the flow rate of the intake gas flowing in the upstream intake passage by controlling the opening degree thereof. Therefore, the upstream intake passage flow rate adjusting valve 24 can adjust the flow rate of the intake gas flowing out from the upstream intake port 6 into the cylinder bore 4.

  Here, the downstream intake port 5 communicates with the cylinder bore 4 so as to generate a swirl in a certain direction in the cylinder bore 4, and the swirl direction velocity component of the intake gas flowing out from the downstream intake port 5 into the cylinder bore 4 is relatively high. large. Accordingly, when the intake gas flows out from the downstream intake port 5 into the cylinder bore 4, a relatively strong swirl is generated in the intake gas in the cylinder bore 4. On the other hand, a slight interference occurs between the flow flowing out from the upstream intake port 6 and the flow flowing out from the downstream intake port 5. When there is a flow from both ports, it acts in a direction lower than the swirl generated by the upstream intake port 6 and the downstream intake port 5 alone. Accordingly, the swirl in the cylinder bore 4 becomes weaker as the outflow amount of the intake gas from the upstream intake port 6 increases. Therefore, according to the present embodiment, if the opening degree of the upstream intake passage flow control valve 24 is increased, the amount of intake gas flowing out from the upstream intake port 6 increases, so that the swirl of the intake gas in the cylinder bore 4 is weakened. If the opening is reduced, the amount of outflow is reduced and the swirl becomes stronger.

  However, if the opening degree of the upstream intake passage flow rate adjustment valve 24 is reduced, the flow passage cross-sectional area of the upstream intake passage is reduced, so that the flow resistance against the intake gas flowing into the cylinder bore 4 increases, and therefore the intake air flowing into the cylinder bore 4 increases. The gas flow rate is reduced. On the contrary, when the opening degree is increased, the flow cross-sectional area of the upstream intake passage is increased, so that the flow resistance is decreased, and thus the flow rate of the intake gas is increased. Therefore, according to the present embodiment, when the opening degree of the upstream intake passage flow rate adjustment valve 24 is increased, the swirl ratio of the intake gas in the cylinder bore 4 is reduced and the intake gas flow rate is increased. When the opening degree of the valve 24 is reduced, the swirl ratio of the intake gas in the cylinder bore 4 is increased and the flow rate of the intake gas is reduced.

  The upstream sub-passage flow rate adjustment valve 25 adjusts the flow rate of the intake gas flowing in the upstream sub-passage by controlling the opening degree thereof. As described above, the intake gas flowing into the cylinder bore 4 from the outlet end 23 through the upstream sub-passage 21 weakens the swirl of the intake gas in the cylinder bore 4. Therefore, increasing the opening degree of the upstream sub-passage flow rate adjustment valve 25 weakens the swirl, and decreasing the opening degree increases the swirl.

  Similarly to the upstream intake passage flow rate adjustment valve 24, the upstream sub passage flow rate adjustment valve 25 also has a smaller flow opening, so that the flow passage cross-sectional area of the upstream sub passage 21 becomes smaller. Therefore, the flow rate of the intake gas flowing out into the cylinder bore 4 is reduced. On the contrary, when the opening degree is increased, the flow cross-sectional area of the upstream sub-passage 21 is increased, so that the flow resistance is reduced, and the flow rate of the intake gas is increased. Therefore, according to the present embodiment, when the opening degree of the upstream sub-passage flow adjustment valve 25 is increased, the swirl ratio of the intake gas in the cylinder bore 4 is reduced and the intake gas flow rate is increased. When the opening of the valve 25 is reduced, the swirl ratio of the intake gas in the cylinder bore 4 is increased and the flow rate of the intake gas is reduced.

  FIG. 6 shows the relationship between the swirl ratio of the swirl generated in the intake gas in the cylinder bore 4 and the flow rate of the intake gas flowing out into the cylinder bore 4. The broken lines in the figure indicate the relationship when the upstream intake passage flow rate adjustment valve 24 is fully opened and the upstream sub-passage flow rate adjustment valve 25 is fully closed. In the direction from the broken line to the arrow R, the relationship between the swirl ratio and the flow rate that changes as the upstream intake passage flow rate regulating valve 24 is closed is shown. The swirl ratio is large and the flow rate is low. I understand. On the other hand, in the direction of the arrow L from the broken line, the relationship between the swirl ratio and the flow rate that changes as the upstream sub-passage flow rate adjustment valve 25 is opened is shown. The swirl ratio gradually decreases and the flow rate increases. I understand that

  Thus, in this embodiment, the relationship between the swirl ratio of the swirl generated in the intake gas over a wide range and the flow rate of the intake gas flowing out into the cylinder bore 4 can be changed, and the relationship between the swirl ratio and the flow rate can be changed. The relationship is changed according to the engine operating state. Here, the engine operating state includes engine speed, engine load, fuel injection amount, intake air amount, and the like. Taking the engine speed as an example, the relationship between the swirl ratio and the flow rate is changed so that the swirl ratio is large at low revolutions and the flow rate is increased at high revolutions.

  As shown in FIGS. 3 and 4, the outlet ends 22 and 23 of the sub passages 20 and 21 protrude from the inner wall surface of the intake ports 5 and 6 in the above embodiment, but the outlet ends 22 and 23 May have a form in which holes are provided in the inner wall surface without protruding from the inner wall surface. In this case, the outlet ends 22 and 23 do not become the flow resistance of the intake gas flowing through the intake ports 5 and 6, but the intake gas flowing out from the outlet ends 22 and 23 flows out from the intake ports 5 and 6. Since it is easy to interfere with the intake gas, the directivity is reduced. The flow rate adjusting valve may be provided not only in the upstream intake passage and the upstream sub passage, but also in the downstream intake passage and the downstream sub passage.

  In both of the above-described embodiments, the protrusions 14 and 15 are provided around the outlet openings 7 and 8 of the both intake ports 5 and 6, respectively, but the protrusion is provided only around the outlet opening 7 of the downstream intake port 5. It may be provided. In this case, the outlet end portion of the upstream sub-passage does not have to be directed in a direction substantially perpendicular to the swirling direction of the intake gas in the cylinder bore 4 and may be directed in the counter-turning direction of the cylinder bore 4. This is because in the above-described embodiment, there is a protrusion on the side of the outlet opening 8 of the upstream intake port 6 opposite to the turning direction, so that the outflowing intake gas may hit the protrusion when the outlet end of the upstream sub-passage is turned in the direction of anti-turning This is because there is a characteristic, but if there is no protrusion, it will not hit. The swirl of the intake gas in the cylinder bore 4 can be effectively weakened by directing the outlet end portion of the upstream sub-passage in the anti-turning direction. Alternatively, the swirl of the intake gas in the cylinder bore 4 may be strengthened when the upstream sub-passage flow rate adjustment valve 25 is opened with the outlet end of the upstream sub-passage directed in the turning direction.

It is a bottom view of the cylinder head corresponding to each cylinder bore. FIG. 2 is a cross-sectional view around an intake port and an intake valve taken along line II-II in FIG. 1. It is a bottom view of a cylinder head corresponding to each cylinder bore in a second embodiment. FIG. 4 is a cross-sectional view around an intake port and an intake valve along line IV-IV in FIG. 3. It is a schematic diagram of an intake port and an intake manifold. It is the figure which showed the relationship between the swirl ratio and flow volume in the intake device of 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder block 3 ... Cylinder head 4 ... Cylinder bore 7, 8 ... Outlet opening 11 ... Intake valve 12 ... Valve body 13 ... Stem 14, 15 ... Projection part 16 ... Restriction wall 17 ... Slope

Claims (6)

An intake port that is provided in the cylinder head and communicates with the cylinder bore, an intake valve that opens and closes an outlet opening of the intake port, and a protruding portion that protrudes from the surface of the cylinder head around the outlet opening of the intake port, In the intake device of the internal combustion engine, the protrusion has a restriction wall that suppresses the intake gas from flowing out from the intake port into the cylinder bore in a direction opposite to the swirling direction of the intake gas in the cylinder bore.
The protruding portion has a slope on the side opposite to the turning direction of the intake gas in the cylinder bore to the upper Symbol regulation wall, the slope radially of the cylinder bore of the intake gas passing over the slope in the radially inner side of the cylinder bore An intake device for an internal combustion engine configured to guide the vehicle so as to turn on the outside .   2. The intake device for an internal combustion engine according to claim 1, wherein the restriction wall protrudes higher than a maximum valve lift amount of the intake valve from a surface of the cylinder head.   The intake device for an internal combustion engine according to claim 1 or 2, wherein a plurality of the intake ports are provided per cylinder, and the protrusions are provided around the outlet openings of the intake ports.   Two adjacent intake ports are provided per cylinder, and the intake gas is tangential to the cylinder bore and along the valve face of the intake valve in the downstream intake port located downstream in the turning direction of the intake ports. The intake device for an internal combustion engine according to claim 3, further comprising a sub-passage for a downstream intake port that flows into the cylinder bore.   Two adjacent intake ports are provided per cylinder, and in the upstream intake port located upstream of the swirl direction among these intake ports, the intake air is in a direction substantially perpendicular to the swirl direction of the intake gas in the cylinder bore. The intake device for an internal combustion engine according to claim 3 or 4, further comprising an upstream intake port sub-passage for allowing intake gas to flow into the cylinder bore along the valve face of the valve.   6. The intake device for an internal combustion engine according to claim 4, wherein the sub passage is configured to be openable and closable based on an engine operating state.

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