JP4513720B2 - Intake port structure of internal combustion engine - Google Patents

Description

  The present invention relates to an intake port structure of an internal combustion engine, and more particularly to an intake port structure of an internal combustion engine provided with a partition wall in the intake port for maintaining a drift state of intake air.

  2. Description of the Related Art Conventionally, techniques for generating a swirling airflow such as tumble (vertical vortex) or swirl (lateral vortex) in a combustion chamber of an internal combustion engine are generally known. Regarding the generation of swirling airflow, the mixing characteristics of the air-fuel mixture is improved, the propagation of flame is promoted and the output of the internal combustion engine is further improved, the lean combustion state is stabilized, the lean combustion region is expanded, and as a result For the purpose of improving the fuel efficiency of an internal combustion engine, various techniques relating to the generation of a swirling airflow, such as a technique for increasing the strength of the swirling airflow to be generated, have been proposed.

  For example, an engine intake device proposed in Patent Document 1 includes an injector holder having an intake passage continuing to an intake port, and a deflection flow for generating a tumble flow is generated in the intake passage of the injector holder. A tumble control valve and a partition wall that maintains the generated deflection flow and leads to the inlet of the intake port are provided. Patent Document 1 discloses a shape of a partition wall (partition plate) that further protrudes into the inlet port of the intake port and that has a notch in a portion where fuel injected from an injector hits. According to the engine intake device proposed in Patent Document 1, the deflected flow for generating the tumble flow is guided to the inlet of the intake port while being maintained by the partition wall as it is. A strong tumble flow is generated.

  Patent Document 2 proposes an engine intake device having the following characteristics. In the engine intake device proposed in Patent Document 2, a partition is provided inside the intake port, and the end of the partition is located immediately before the intake valve. In Patent Document 2, a shape in which the end portion of the partition wall is cut obliquely, and a triangular portion in which fuel droplets are smoothly collected and dropped are formed on one or both of the inside and outside of the end portion, and Is disclosed. According to the engine intake device proposed in Patent Document 2, when a tumble flow is generated by dividing an intake port by a partition wall, it is possible to prevent fuel from adhering to the partition wall and deteriorating fuel consumption.

Japanese Utility Model Publication No. 7-25230 JP-A-6-159203

  Here, when the downstream end portion of the partition wall is partially shortened (for example, the notch of the terminal end portion proposed by Patent Document 1 or the triangular portion proposed by Patent Document 2), the partition wall is passed through that portion. Intake flow that had been suppressed in the flow. In other words, by partially shortening the downstream end, the flow rate of the intake air flowing into the combustion chamber can be partially increased, and as a result, the strength of the intake air flow flowing into the combustion chamber can be partially increased. It is. In order to generate a stronger swirling airflow in the combustion chamber based on this point of view, the intake flow intensity is maintained at the partition wall to the vicinity of the intake valve, and the intake air flow intensity is less affected by the intake valve. It is effective to increase it. However, the downstream end shape of the partition wall disclosed in Patent Documents 1 and 2 is formed based on a technical idea different from such a viewpoint, so that a stronger swirling airflow is generated. The shape is not necessarily effective for the purpose of generation.

  Therefore, the present invention has been made in view of the above problems, and the partition provided in the intake port maintains the drift state of the intake flow and further partially increases the strength of the intake flow, resulting in combustion. An object of the present invention is to provide an intake port structure for an internal combustion engine capable of generating a swirling air flow having higher strength in a room.

In order to solve the above-described problems, the present invention provides an intake port structure for an internal combustion engine having a partition wall in the intake port for maintaining a drift state of the intake flow, and an end portion on the downstream side of the partition wall includes the internal combustion engine Extending to the vicinity of the intake valve provided in the engine, to one region of the combustion chamber divided into two on the plane perpendicular to the crank axis, including the central axis of the combustion chamber of the internal combustion engine, of the downstream end portion The portion corresponding to the intake flow toward the other region extends more than the portion corresponding to the intake flow toward, and corresponds to the intake flow toward the center of the combustion chamber among the downstream end portions. The portion is further shortened .

According to the present invention, it is possible to increase the strength of the intake air flow by maintaining the intake air drift state up to the vicinity of the intake valve and further partially increase the strength of the intake air flow toward the center of the combustion chamber. In addition, the intake air flow toward the center of the combustion chamber has little interference with the stem portion of the intake valve, and smoothly flows into the combustion chamber along the umbrella shape of the intake valve. An airflow can be generated. Further, according to the present invention, a tumble flow including a swirl component can be generated as a swirling air flow generated in the combustion chamber. Thereby, it is possible to generate a swirling airflow having higher strength in the combustion chamber.

  Note that the downstream end according to the present invention is shortened for the purpose of partially further increasing the strength of the intake air flow toward the center of the combustion chamber with little interference with the stem portion of the intake valve. This is different from the terminal portion disclosed in FIG. That is, the downstream end portion according to the present invention is based on the above-mentioned meaning, and the portion corresponding to the intake flow toward the central portion of the combustion chamber in the downstream end portion is the internal combustion engine such as the arrangement and shape of the intake valve. It is shortened with an appropriate shape in consideration of the specifications and the ease of manufacturing such as processing.

Further, the present invention provides the downstream end portion to a position where the stem portion of the intake valve is at least partially included in the region formed by the further shortened portion of the downstream end portion. May be stretched. More specifically, if the downstream end of the partition wall extends to the above-mentioned position as the vicinity of the intake valve, the drift state of the intake air flow can be maintained accordingly, and as a result, the combustion chamber has higher strength. A swirling airflow can be generated.

  According to the present invention, by the partition wall provided in the intake port, the drift state of the intake flow is maintained and the strength of the intake flow is partially increased. As a result, a swirling air flow having higher strength is generated in the combustion chamber. It is possible to provide an intake port structure for an internal combustion engine capable of performing

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a main part of an internal combustion engine 50A including an intake port structure (hereinafter simply referred to as an intake port structure) 100A of the internal combustion engine according to the present embodiment. FIGS. 1A and 1B are both a vertical sectional view of an internal combustion engine 50A provided with an intake port structure 100A, and FIG. 1A shows a case where the airflow control valve 2 is in an open state. FIG. 1B shows a case where the airflow control valve 2 is in a closed state. FIG. 1C is a horizontal sectional view of the internal combustion engine 50A shown in FIG. 1B, and shows a combustion chamber 53, an intake valve 54, and an exhaust valve 55 as main parts of the internal combustion engine 50A together with the intake port structure 100A. It is. The intake port structure 100A according to the present embodiment is realized by an intake port 52aA having a partition wall 1A, an airflow control valve 2, and a valve shaft 3 in the intake port 52aA. The intake port 52aA is formed in the cylinder head 52 and is configured to guide intake air to the combustion chamber 53 of the internal combustion engine 50A. An intake valve 54 that opens and closes the flow path of the intake port 52aA is disposed in the cylinder head 52, and a stem portion 54a of the intake valve 54 is interposed in the intake port 52aA.

  The fuel injection valve 56 is disposed with its injection hole protruding into the intake port 52aA on the downstream side of the partition wall 1A and the injection direction directed into the combustion chamber 53. Thereby, the injected fuel is suitably atomized without adhering to the partition wall 1A, and an increase in emission in the exhaust gas and a deterioration in fuel consumption are suppressed. Further, the effect of increasing the strength of the swirling airflow generated in the combustion chamber 53 is synergistically expanded by the vaporization latent heat effect of the fuel directly injected into the combustion chamber 53, and the atomization is promoted. Mixing properties are also improved. The fuel injection valve 56 may be disposed in the combustion chamber 53 so that the injection hole protrudes, and the above-described effect is lost, but the fuel injection valve 56 is injected into the intake port 52aA upstream of the airflow control valve 2. You may arrange | position the fuel injection valve 56 in the state which protruded the hole.

  The airflow control valve 2 is configured to control the flow rate and flow of the intake air within the intake port 52aA, and the opening degree is changed according to the operating state of the internal combustion engine 50A such as the load and the rotational speed. The airflow control valve 2 is pivotally supported by the valve shaft 3, and the opening degree is changed by rotating the valve shaft 3. The valve shaft 3 is rotated by an actuator (not shown) that is driven under the control of an ECU (electronic control unit) (not shown). The airflow control valve 2 and the valve shaft 3 are disposed on the upstream side of the partition wall 1A, and the state in which the airflow control valve 2 shown in FIG. 1A is in contact with the upper wall surface of the intake port 52aA is fully opened. The state in which the tip of the airflow control valve 2 shown in b) is close to the upstream end of the partition wall 1A is fully closed, and this fully closed and fully open range is the opening range. The airflow control valve 2 is stored on the upper wall surface of the intake port 52aA formed so that the airflow control valve 2 can be stored when fully opened so as not to obstruct the intake flow.

  The airflow control valve 2 and the valve shaft 3 are not limited to the upper wall surface side of the intake port 52aA shown in FIGS. 1A and 1B. For example, a reverse tumble flow (combustion chamber on the intake port 52aA side) in the combustion chamber 53 is used. 53, it may be disposed on the lower wall surface side of the opposed intake port 52aA, or the like. Based on the specifications of the intake port 52aA such as the angle at which 52aA faces the combustion chamber 53, it is not limited to the upper wall surface side and the lower wall surface side, and may be disposed on an appropriate wall surface side.

  The partition wall 1 </ b> A is configured to maintain the drifting state of the intake flow drifted by the airflow control valve 2 up to the vicinity of the intake valve 54. The partition wall 1A is disposed at a position that substantially bisects the flow path in the intake port 52aA into a flow path F1 and a flow path F2 along the flow direction of the intake air. However, the present invention is not limited to this, and may be disposed at an appropriate position based on the specifications of the intake port 52aA such as an angle facing the combustion chamber 53, for example. Further, the surface on which the partition wall 1A forms the flow paths F1 and F2 and the surface on which the airflow control valve 2 controls the intake air flow are substantially perpendicular to the same plane (the paper surface in this embodiment). As shown in FIG. 1 (c), the downstream end of the partition wall 1A is formed substantially in parallel with the extending direction of the valve shaft 3, and its central portion is cut into a semicircle (shortened). ) In the present embodiment, the excised semicircular portion is a portion corresponding to the intake air flow toward the central portion of the combustion chamber 53. Further, the downstream end of the partition wall 1A extends to a position where the stem portion 54a of the intake valve 54 is partially included in a semicircular cut region (region formed by a shortened portion) A1. Stretched.

  Note that the downstream end shape of the partition wall 1A is simply referred to as a center enlarged shape hereinafter. In addition, the end shape that is not cut in a semicircular shape with respect to the downstream end shape of the partition wall 1A is simply referred to as a straight shape. Further, the intake air flow toward the center of the combustion chamber 53 is more specifically an intake air flow that flows into the combustion chamber 53 through the stem portion 54a of the intake valve 54 as shown in FIG. When there are three intake valves 54 per cylinder, the intake flow flows into the combustion chamber 53 through the stem portions 54a of the intake valves 54 at both ends. However, the center enlarged shape does not require that the entire end portion of the partition wall 1A corresponding to the intake air flow between the stem portions 54a of the intake valve 54 be cut off. That is, a part of the end portion of the partition wall 1A corresponding to the intake air flow between the stem portions 54a of the intake valve 54 may be partially cut off. On the contrary, the center enlarged shape includes a portion corresponding to the intake air flow between the stem portions 54a of the intake valve 54 as shown in FIG. 1 (c), and is further cut out to a range including the stem portion 54a. Good. Moreover, the center enlarged shape may not be cut in a semicircular shape, and may be cut in a polygonal shape such as a quadrangle. That is, it is only necessary to be cut out in an appropriate shape in consideration of the effects described later obtained by the center enlarged shape, the specifications of the internal combustion engine 50A such as the shape and arrangement of the intake valve 54, the ease of manufacturing such as processing, and the like.

  The internal combustion engine 50A is a direct injection gasoline engine. However, for example, the intake port structure 100A according to this embodiment can be applied to a so-called lean burn engine. Also, in the case of an internal combustion engine in which the effect of improving the output can be obtained by improving the mixing property of the air-fuel mixture based on the improvement of the strength of the swirling airflow in combusting the air-fuel mixture, this embodiment also applies to other gasoline engines, diesel engines, etc. Such an intake port structure 100A can be applied.

  As shown in FIG. 1A or 1B, the internal combustion engine 50A includes a cylinder block 51, a cylinder head 52, and the like. A substantially cylindrical cylinder 51a is formed in the cylinder block 51, and a substantially cylindrical cylinder liner (not shown) is disposed on the inner peripheral surface of the cylinder 51a. A piston (not shown) is accommodated in the cylinder 51a via the cylinder liner. When the piston reciprocates within the cylinder 51a, power is transmitted to a crankshaft (not shown) via a connecting rod (not shown), and the crankshaft converts the reciprocating motion into a rotational motion. Note that the crank axis is an axis substantially parallel to the center line P1 shown in FIG.

  A cylinder head 52 is fixed to the upper surface of the cylinder block 51, and the combustion chamber 53 is formed as a space surrounded by the cylinder block 51, the cylinder head 52 and the piston. In addition to the intake port 52aA described above, the cylinder head 52 is formed with an exhaust port 52b for exhausting the combusted gas from the combustion chamber 53, and an exhaust valve 55 for opening and closing the flow path of the exhaust port 52b is provided. It is installed. Further, the cylinder head 52 is provided with a spark plug 57 with a tip protruding from the top of the combustion chamber 53.

  Next, a process of generating a tumble flow (swirl airflow) in the combustion chamber 53 with the above-described configuration will be described in detail with reference to FIG. As shown in FIG. 1B, when the intake valve 54 is opened during the intake stroke, an intake flow is generated in the intake port 52aA due to the negative pressure generated in the combustion chamber 53. When the airflow control valve 2 is in the fully closed state, the intake air flow is biased by the airflow control valve 2, and the drifted intake air flow (hereinafter also simply referred to as a deflected flow) passes through the flow path F1 formed by the partition wall 1A. To do. When the partition wall 1A suppresses the diffusion of the deflected flow, the deflected flow reaches the vicinity of the intake valve 54 in a state where the deflected state is maintained, that is, in a state where the strength increased by the drift is maintained.

  The deflected flow that has reached the vicinity of the intake valve 54 tends to diffuse through the region A1 that has been cut out by the center enlarged shape. Therefore, the flow rate of the intake air toward the central portion of the combustion chamber 53 is increased, and the strength of the intake air flow toward the central portion of the combustion chamber 53 among the intake air flows flowing into the combustion chamber 53 is partially increased. Furthermore, since this intake air flow passes between the stem portions 54a of the two intake valves 54 as shown in FIG. 1 (c), it follows the umbrella shape of the intake valves 54 in a state where interference with the stem portions 54a is avoided. And smoothly flows into the combustion chamber 53. The arrow shown in FIG. 1C schematically indicates the magnitude of the flow rate of the intake air flowing into the fuel chamber 53 by the length of the arrow. The intake air flow that has flowed into the combustion chamber 53 in this manner is sequentially changed in the combustion chamber 53 wall surface, piston crown surface, etc. on the exhaust valve 55 side, and as schematically shown by arrows in FIG. Produced in a stronger tumble stream.

  Next, the relationship between the strength of the tumble flow (hereinafter simply referred to as tumble strength) and the valve lift amount of the intake valve 54 will be described in detail with reference to FIG. To do. FIG. 2 shows a case where an intake port structure 100A and an intake port structure 100X having a partition wall 1X having a straight end shape on the downstream side are applied to the internal combustion engine 50. The intake port structure 100X has the same structure as the intake port structure 100A except that the downstream end shape is different. As shown in FIG. 2, when the valve lift amount is in the small and medium region, the tumble strength is improved in the intake port structure 100A than in the intake port structure 100X. That is, in the case where the intake port structure 100A is applied, the intake valve 54 is prevented from becoming resistance to the intake flow in the small and middle region of the valve lift amount, and the intake flow is made to flow into the combustion chamber 53 most smoothly. Can do. In other words, when the intake port structure 100A is applied, it is possible to increase the tumble strength in the middle and middle regions of the valve lift amount by actively collecting the intake air flow at the center of the combustion chamber 53.

  Next, the relationship between the tumble strength and the valve lift amount of the intake valve 54 will be described in detail with reference to FIG. 3 when the downstream end position of the partition wall 1 is different. FIG. 3 shows a case where the downstream end positions are “near the intake valve 54”, “substantially the center in the intake port 52aA”, and “the inlet portion of the intake port 52aA”. The downstream end shape of the partition wall 1A is an enlarged center shape shown in FIG. Further, the positions are close to the combustion chamber 53 in the order of “in the vicinity of the intake valve 54”, “approximately the center in the intake port 52aA”, and “inlet portion of the intake port 52aA”. As shown in FIG. 3, the tumble strength increases as the downstream end position approaches the combustion chamber 53 in the entire valve lift amount. That is, as the downstream end position is closer to the vicinity of the intake valve 54, the strength of the deflected flow can be maintained, and as a result, a tumble flow having higher strength can be generated.

  Next, the relationship between the tumble strength and the intake air flow rate will be described in detail with reference to FIG. 4 when the downstream end shape of the partition wall 1 is different. FIG. 4 shows a case where the intake port structure 100A and the intake port structure 100X are applied to the internal combustion engine 50 as in FIG. As shown in FIG. 4, when generating a tumble flow having the same target tumble strength T, the intake air flow rate is greater when the intake port structure 100A is applied than when the intake port structure 100X is applied (S2− Increase by S1). This is because when the tumble flow having the target tumble strength T is generated, the intake port structure 100X maintains lean combustion according to the intake port structure 100A even in a load region where the intake flow rate becomes insufficient and lean combustion cannot be maintained. It means that it is possible. That is, by applying the intake port structure 100A, it is possible to expand the lean combustion region.

  Next, the intake port structure 100A when the intake port 52a is an independent port will be described in detail with reference to FIG. In FIG. 5, the intake port structure 100 </ b> A is shown in a horizontal sectional view together with the combustion chamber 53, the intake valve 54, and the exhaust valve 55, as in FIG. In the case of the siamese port 52aA in which the intake port 52a branches in the middle as shown in FIG. 1C, the intake port structure 100A is provided by providing one partition wall 1A per cylinder of the internal combustion engine 50A. Is realized. In the case of the intake two-valve independent port 52aB, as shown in FIG. 5, the partition walls 1Aa and 1Ab formed by dividing the partition wall 1A shown in FIG. 1 (c) into two parts are respectively connected to the intake ports 52aBa and 52aBb. In this case, the intake port structure 100A can be realized. In this case, two partition walls 1Aa and 1Ab are disposed per cylinder. In the case of the intake three-valve independent port, the intake port structure 100A can be realized by disposing each partition formed so as to divide the partition 1A shown in FIG. is there. In this case, three partition walls are provided per cylinder. Each of the intake ports described above is a specific example of the intake port 52a. If there are other applicable intake ports, the application of the intake port structure 100A to the intake ports is not limited. . As described above, it is possible to realize the intake port structure 100A capable of maintaining the uneven flow state of the intake flow and partially increasing the strength of the intake flow, and as a result, generating a stronger tumble flow in the combustion chamber 53. It is.

The intake port structure 100B in the present embodiment is the same as the intake port structure 100B shown in Embodiment 1, except that the shape of the downstream end of the partition wall 1B is different. FIG. 6 is a view showing the intake port structure 100B in a horizontal sectional view together with the combustion chamber 53, the intake valve 54, and the exhaust valve 55, as in FIG. In the present embodiment, the downstream end of the partition wall 1 </ b> B is cut obliquely with respect to the extending direction of the valve shaft 3. Thus, in the intake port structure 100B, the portion 1B corresponding to the intake flow toward the one region 53a of the combustion chamber 53 divided into two on the plane orthogonal to the crank axis includes the central axis P2 of the combustion chamber 53 of the internal combustion engine 50B than c, towards the part 1B d corresponding to the intake flow toward the other region 53b is realized downstream of the shape of the partition wall 1B stretched. Note that the above-described obliquely cut end shape is hereinafter simply referred to as an inclined shape.

  By cutting off the downstream end of the partition wall 1B as described above, the cut regions A2 and A3 are gradually enlarged from one end side to the other end side in the extending direction of the valve shaft 3, so that the combustion chamber 53 The flow rate of intake air toward one region 53a is larger than the flow rate of intake air toward the other region 53b. The arrow shown in FIG. 6 schematically shows the intake flow rate, and the length of the arrow indicates the magnitude of the intake flow rate. Thereby, a tumble flow having a swirl component can be generated from the intake air flow. The tumble flow having the swirl component can improve the stability of the swirling airflow in the combustion chamber 53 as compared with the case of only the tumble flow, and can improve the tumble strength correspondingly, and the lean combustion state. Stabilization can be further improved.

  In forming the downstream end, if the portion 1Bc is shorter than the portion 1Bd, it is not necessary to be cut obliquely, for example, the end may be formed in an arc shape, It may be formed in a step shape. In forming the end portion, the portion 1Bc only needs to be shortened as a whole as compared with the portion 1Bd. For example, the portion 1Bc may include a shape partially extended from the portion 1Bd. That is, the region A2 cut out at the portion 1Bc only needs to be larger than the region A3 cut out at the portion 1Bd.

  6 shows the case where the intake port 52a is the Siamese port 52aA. However, when the intake port structure 100B is realized by the independent two-valve intake port 52aB, for example, the partition wall 1B shown in FIG. 6 is divided into two. The partition walls formed as described above may be disposed in each intake port. Further, when the intake port structure 100B is realized by the independent three-valve intake port, for example, the partition walls formed by dividing the partition wall 1B shown in FIG. 6 into three parts are arranged in the respective intake ports according to the arrangement order. That's fine. Also, when the intake port structure 100B is realized by the independent two-valve intake port 52aB or the independent three-valve intake port, the end portion does not necessarily have to be formed in an inclined shape like the partition wall 1B shown in FIG. That is, the end portions may be formed so that the end portions of the partition walls of each intake port are extended or shortened in the arrangement order. Further, when the intake port structure 100B is realized by an independent intake port, it is possible to generate a stronger tumble flow in the combustion chamber 53 by extending the end of the partition wall to the vicinity of the intake valve 54. As described above, it is possible to realize the intake port structure 100 </ b> B capable of maintaining the uneven flow state of the intake flow and partially increasing the strength of the intake flow, and as a result, generating a stronger tumble flow in the combustion chamber 53. It is.

  The intake port structure 100C in the present embodiment is the same as the intake port structure 100A shown in the first embodiment except that the shape of the downstream end of the partition wall 1C is different. FIG. 7 shows an intake port structure 100C according to a third embodiment having a partition wall 1C formed with a shape in which a downstream end portion is combined with an inclined shape and a center enlarged shape, and a combustion chamber 53, an intake valve 54, and an exhaust valve 55. It is a figure shown with horizontal cross section view. In this case, the tumble flow having the swirl component can be further strengthened in the small and middle region of the valve lift by the center enlarged shape.

  Although the intake port 52a shown in FIG. 7A is the case of the siamese port 52aA, the intake port structure 100C can be applied as shown in FIG. 7B even in the case of the siamese port 52aC branched into three. is there. In this case, due to the arrangement of the intake valve 54, the intake flow easily flows into the combustion chamber 53 along the umbrella shape of the intake valve 54. Therefore, it is possible to generate a tumble flow having a swirl component having a higher tumble strength in the small and middle region of the valve lift. In addition, both the intake port structures 100A and 100C can adjust the intake flow rate according to the degree of size of the ablation region due to the center enlarged shape, so that it is possible to generate a tumble flow having a tumble strength and intake flow rate more suitable for operating conditions. It is.

  When the intake port structure 100C is realized by the independent two-valve intake port 52aB, each partition formed so as to divide the partition 1C shown in FIG. Further, when the intake port structure 100C is realized by the independent three-valve intake ports, the partition walls formed by dividing the partition wall 1C shown in FIG. . Further, a tumble flow generated in the combustion chamber 53 is formed by forming an enlarged central shape so that the stem portion of the intake valve 54 is included in the excised region A1 and extending the downstream end to the vicinity of the intake valve 54. It is possible to further increase the strength. Further, similarly to the case described in the first and second embodiments, the center enlarged shape and the inclined shape of the downstream end of the partition wall 1C can be variously modified. As described above, it is possible to realize the intake port structure 100 </ b> C capable of maintaining the uneven flow state of the intake flow and partially increasing the strength of the intake flow, and as a result, generating a stronger tumble flow in the combustion chamber 53. It is.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

It is a figure which shows the principal part of internal combustion engine 50A provided with the intake port structure 100A which concerns on a present Example. FIG. 6 is a diagram showing the relationship between tumble strength and the valve lift amount of the intake valve 54 when the downstream end shape of the partition wall 1 is different. FIG. 6 is a diagram showing the relationship between tumble strength and the valve lift amount of the intake valve 54 when the downstream end position of the partition wall 1 is different. It is a figure which shows the relationship between tumble intensity | strength and intake air flow rate, when the edge part shape of the downstream of the partition 1 differs. It is a figure which shows 100 A of intake port structures in case the intake port 52a is an independent port with the combustion chamber 53, the intake valve 54, and the exhaust valve 55 by horizontal sectional view. It is a figure which shows the intake port structure 100B with the combustion chamber 53, the intake valve 54, and the exhaust valve 55 in a horizontal sectional view. The intake port structure 100C according to the third embodiment having the partition wall 1C formed in a shape in which the downstream end is combined with the inclined shape and the center enlarged shape, together with the combustion chamber 53, the intake valve 54, and the exhaust valve 55, is viewed in a horizontal sectional view. It is a figure shown by.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bulkhead 2 Airflow control valve 3 Valve shaft 50 Internal combustion engine 51 Cylinder block 52 Cylinder head 52a Intake port 52b Exhaust port 53 Combustion chamber 54 Intake valve 55 Exhaust valve 100 Intake port structure

Claims (2)

An intake port structure for an internal combustion engine provided with a partition wall in the intake port for maintaining a drift state of the intake flow,
The downstream end of the partition extends to the vicinity of the intake valve provided in the internal combustion engine,
Of the downstream side end portion, including the central axis of the combustion chamber of the internal combustion engine and the portion corresponding to the intake flow toward one region of the combustion chamber divided into two by a plane perpendicular to the crank axis, The part corresponding to the intake flow toward the area is extended,
An intake port structure for an internal combustion engine , wherein a portion of the downstream end corresponding to an intake flow toward the center of the combustion chamber is further shortened . The downstream end portion extends to a position where the stem portion of the intake valve is at least partially included in a region formed by the further shortened portion of the downstream end portion. The intake port structure for an internal combustion engine according to claim 1.

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