JP2005113737A - Internal combustion engine equipped with suction port for forming tumbling flow - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine equipped with a suction port in which a strong tumbling flow can be formed in a cylinder while securing a suction air quantity necessary for the combustion. <P>SOLUTION: In the internal combustion engine 1, two suction ports 2 are installed in order for a cylinder 3, and each port is formed to direct the suction into the cylinder so that tumbling flow T is formed in the cylinder. An edge 7 is formed inside the arranging direction of each suction port out of the wall surface of the suction port and at a boundary of a wall face 2a at the opposite side with respect to the side where the suction forming the tumbling flow is introduced and a throat section 6a of a valve seat 6 connected to the suction port. Out of the boundary of the wall surface of the suction port and the throat section, the other than the boundary forming the edge is formed into a smooth roundness 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine provided with an intake port suitable for forming a tumble flow in a cylinder.

Intake ports of various structures have been proposed for the purpose of improving the combustion of internal combustion engines. For example, an intake port is known that eccentrically accelerates the air flowing into the cylinder by making the seat shape of the intake valve asymmetrical in order to generate a turning motion around the cylinder axis in the cylinder (Patent Literature). 1). In addition, an intake port that reduces swirl generation by reducing the intake resistance by configuring the inner throat surface of the intake valve seat to have an asymmetric inclination is known (see Patent Document 2).
JP-A-60-156915 Japanese Utility Model Publication No.59-67503

  As one of the measures for improving the combustion of the internal combustion engine, it is known to form a tumble flow of the intake air swirling along the axial direction of the cylinder in the cylinder. The tumble flow is formed by directing intake air through the intake port and directing it into the cylinder. In such an intake port for forming a tumble flow, a part of the intake air changes the flow direction along the intake valve and flows into the opposite region in the cylinder. This intake flow may flow in a direction opposite to the tumble flow and weaken the tumble flow.

  By the way, the boundary between the wall surface of the intake port and the throat portion of the valve seat connected to the intake port is formed in an edge shape (all-round edge) or a round shape (all-round radius). In the case of the all-around edge, the flow of the intake air introduced along the wall surface of the intake port is separated by the edge. As a result, a strong tumble flow can be formed in the cylinder by disturbing the flow of a part of the intake flow (opposite intake flow) that flows in the direction opposite to the tumble flow. The amount decreases. Therefore, there is a possibility that the intake air amount necessary for combustion cannot be secured. On the other hand, in the case of an all-round radius, the intake air amount can be increased because the flow of the intake air is not separated, but the tumble flow is weakened because the flow of the opposed intake air flow is not separated. The above-described conventional intake port is intended to strengthen the swirl flow, and does not take into account the above-described problem in the case of forming a strong tumble flow while securing the intake air amount.

  Accordingly, an object of the present invention is to provide an internal combustion engine including an intake port capable of forming a strong tumble flow in a cylinder while securing an intake air amount necessary for combustion.

  In the first internal combustion engine of the present invention, two intake ports are provided side by side with respect to one cylinder, and each intake port directs intake air to the cylinder so that a tumble flow is formed in the cylinder. In the internal combustion engine configured as described above, the wall surface of the intake port is arranged on the inner wall side of each intake port and on the wall surface on the opposite side to the side where the intake air forming the tumble flow is introduced and the intake port An edge is formed at the boundary with the throat portion of the continuous valve seat, and the boundary between the wall surface of the intake port and the throat portion other than the boundary where the edge is formed is formed in a smooth rounded shape. This problem is solved (claim 1).

  According to the first internal combustion engine of the present invention, the wall surface on the opposite side with respect to the side where the intake air forming the tumble flow is introduced inside the intake port wall surface in the arrangement direction of the intake port wall surface (opposite inner wall surface) Since the flow of the intake air introduced along the edge is separated by the edge, the flow velocity of the intake air flowing in the direction opposite to the tumble flow can be suppressed. Therefore, a strong tumble flow can be formed in the cylinder. Further, since the boundary other than the edge of the boundary between the wall surface of the intake port and the throat portion is formed in a smooth rounded shape, the flow of intake air introduced along the wall surface other than the opposite inner wall surface is not separated. Therefore, the intake air amount necessary for combustion can be ensured by the intake air flowing into the cylinder along the wall surface in this range.

  In the second other internal combustion engine of the present invention, two intake ports are provided side by side with respect to one cylinder, and each intake port directs intake air so that a positive tumble flow is formed in the cylinder. An internal combustion engine configured to be guided into a cylinder, wherein a wall surface of the intake port on the inner side in the arrangement direction of each intake port and on a side located on an outer periphery of the cylinder and a throat of a valve seat connected to the intake port An edge is formed at the boundary with the portion, and the above-described problem is solved by forming a smooth round shape except for the boundary between the wall surface of the intake port and the throat portion except the boundary where the edge is formed. (Claim 2).

  According to the second internal combustion engine of the present invention, the flow of intake air guided along the wall surface (outer peripheral inner wall surface) on the inner side in the arrangement direction of the intake ports and on the outer periphery of the cylinder among the wall surfaces of the intake ports. It can be peeled off by the edge. Therefore, it is possible to suppress the influence of the flow formed in the cylinder by the intake air flowing along the outer peripheral inner wall surface on the positive tumble flow. Therefore, a strong positive tumble flow can be formed in the cylinder. Moreover, since the intake air introduced along the wall surfaces other than the outer peripheral inner wall surface flows into the cylinder without being separated from the wall surface, the intake air amount necessary for combustion can be ensured.

  According to the present invention, it is possible to form a strong tumble flow in the cylinder by suppressing the flow facing the tumble flow by the edge, so that fuel and air are mixed well and combustion of the internal combustion engine is improved. Can do. Further, since the amount of intake air necessary for combustion can be ensured by the R formed at the boundary other than the edge, the output of the internal combustion engine can be improved.

  FIG. 1 shows a main part of an internal combustion engine 1 according to an embodiment of the present invention, and FIGS. 2 and 3 show the outline of an intake port 2 connected to the internal combustion engine 1. 2 shows an outline of the two intake ports 2 associated with one cylinder 3 of the internal combustion engine 1 when viewed from the right side of FIG. 1, and FIG. 3 (a) is an intake port on the upper side of FIG. FIG. 3B shows the contour when the upper intake port 2 of FIG. 1 is viewed from the direction of the arrow B. FIG. However, in the present invention, the number of cylinders 3 and their arrangement with respect to the internal combustion engine 1 are arbitrary.

  The internal combustion engine 1 in FIG. 1 has two intake ports 2 and 2 on one side (right side in FIG. 1) 3a with respect to the center line CC of the cylinder 3, and two exhausts on the other side (left side in FIG. 1) 3b. Ports 4 and 4 are provided side by side. As shown in FIG. 3, the intake port 2 extends from the side of the cylinder 3 toward the center line CC of the cylinder 3 while maintaining a substantially constant angle. Therefore, the intake air flowing along the intake port 2 is directed and guided to the other side 3 b of the cylinder 3. Each intake port 2 is provided with a valve guide portion 5. A valve seat 6 is provided at the end of each intake port 2.

  As is apparent from FIGS. 2 and 3, the intake air that forms the tumble flow T on the inner side in the arrangement direction of each intake port 2 in the boundary between the intake port 2 and the throat portion 6 a of the valve seat 6 that is connected to the intake port 2. An edge 7 is formed at the boundary between the wall surface (outer peripheral inner wall surface) 2a opposite to the introduction side (the outer peripheral side of the cylinder 3) 2a and the throat portion 6a. On the other hand, of the boundary between the intake port 2 and the throat portion 6a, except for the boundary where the edge 7 is formed, it is formed into a smooth radius 8. In addition, an edge 7 and a round 8 are formed on the boundary of the lower intake port 2 in FIG. 1 symmetrically with respect to the upper intake port 2 in FIG.

  The range in which the edge 7 is formed is set by the inclination of the intake port 2. For example, when the intake port 2 is provided from the upper side toward the cylinder 3 from the inclination of FIG. 3, the range in which the edge 7 is formed is set narrow. On the other hand, when the intake port 2 is provided from the lateral direction toward the cylinder 3 rather than the inclination of FIG. 3, the range in which the edge 7 is formed is set wider.

  According to the above configuration, the intake air introduced into the cylinder 3 along the outer peripheral inner wall surface 2a can be separated by the edge 7 and the flow velocity of the air flowing in the directions of arrows F and G in FIG. On the other hand, the air flowing in the directions of arrows C, D, and E in FIG. 1 is not separated from the wall surface of the intake port 2 by the radius 8, and is thus introduced into the cylinder 3 while maintaining the flow rate. Note that the flow velocity of air flowing in from the lower intake port 2 in FIG. 1 is vertically symmetric with respect to the upper intake port 2 in FIG.

  FIG. 4A shows the flow velocity distribution of the intake air at the upper intake port 2 outlet of FIG. As a comparative example, FIG. 4B shows the flow velocity distribution of the intake air when the boundary between the wall surface of the intake port 2 and the throat portion 6a is an edge over the entire circumference (the entire circumference edge). Shows the flow velocity distribution of the intake air when the boundary is rounded over the entire circumference. As can be seen from FIG. 4A, the edge 7 can weaken the flow of intake air to the inside of the intake port 2 in the direction of arrangement (directions of arrows F and G). In addition, since the intake air flowing to the outside of the intake port 2 in the direction of arrangement (in the direction of arrow E) is introduced into the cylinder 3 without being separated, the intake air is compared with the case of the all-around edge (FIG. 4B). The flow rate can be increased.

  FIG. 5A shows a longitudinal section of the cylinder 3 along the line V-V in FIG. 1, and an arrow in FIG. 5 shows an example of the flow of the air-fuel mixture in the cylinder 3. Further, as a comparative example, FIG. 5B shows an example of the flow of the air-fuel mixture in the cylinder 3 in the case of all rounds. Note that arrows H in FIGS. 5A and 5B indicate the flow rates of the intake air flowing out inward in the direction in which the intake ports 2 are arranged. As is clear from FIG. 5A, in the intake port 2 in FIG. 1, the flow rate of the intake air flowing out in the directions of arrows F and G in FIG. 1 is suppressed by the edge 7 (the arrow H in FIG. 5A is small). Therefore, a strong substantially circular tumble flow T can be formed in the cylinder 3. On the other hand, in FIG. 5 (b), the flow rate of the intake air in the directions of arrows F and G in FIG. 1 is larger than that in FIG. 5 (a) (see FIG. 4 (c)). As a result, an elliptical tumble flow T is formed.

  FIG. 6 shows the relationship between the intake air amount and the strength of the tumble flow (tumble ratio). The tumble ratio is a ratio between the rotational speed of the tumble flow T and the rotational speed of the internal combustion engine 1. In the case of the intake port at the all-around edge, a strong tumble flow can be formed, but since the intake air amount decreases, the lower right tendency is shown in FIG. On the other hand, in the case of an all-around rounded intake port, the amount of intake air increases, but the tumble flow is weakened, so the upper left tendency is shown in FIG. Therefore, these intake ports show the relationship of line L in FIG. In the intake port 2 of the present invention, only the boundary between the outer peripheral inner wall surface 2a and the intake port 6a is formed at the edge 7 and the other boundary is formed at the round 8, so that a strong tumble flow T is formed and the internal combustion engine 1 is The amount of intake air necessary for combustion can be secured. Therefore, the relationship between the intake air amount and the strength of the tumble flow can be changed in the direction of the upper right point I in FIG.

  The edge 7 and the round 8 in the present invention are manufactured by machining as shown in FIG. 7, for example. The cylinder head 11 provided with the intake port 2 is manufactured by machining a cast product. When the cylinder head 11 is cast, a round 8 is formed over the entire circumference at the boundary between the wall surface of the intake port 2 and the throat portion 6a. After the cylinder head 11 is cast, a part 11a of the cylinder head that is processed into a round shape is cut by the throat cutter 12 from the end side of the intake port 2. By this cutting, the edge 7 is formed. On the other hand, since the throat cutter 12 does not cut the part other than the range where the edge 7 is processed, the round 8 can be formed by leaving the round at the time of casting.

  The present invention is not limited to the embodiments described above, and may be implemented in various forms. For example, in the present embodiment, a normal tumble flow is formed in the cylinder, but the present invention is also applicable to an internal combustion engine provided with an intake port that forms a reverse tumble flow in the cylinder. As long as the internal combustion engine has two intake ports arranged side by side with respect to one cylinder, the intake ports are not limited to being independent. For example, the present invention can also be applied to an internal combustion engine having a so-called siamese type intake port in which one intake port branches in the middle to become two intake ports. The number of exhaust ports is not limited to two. For example, the present invention can be applied to an internal combustion engine having one exhaust port.

The figure which shows the principal part of the internal combustion engine which concerns on one Embodiment of this invention. The figure which shows the outline when the intake port of FIG. 1 is seen from the right side of FIG. The figure which shows the outline when the upper intake port of FIG. 1 is seen from the upper side and lower side of FIG. The figure which shows the flow velocity distribution of the intake air in the upper intake port exit of FIG. The figure which shows an example of the flow of the air-fuel | gaseous mixture in the cylinder of FIG. The figure which shows the relationship between the amount of intake air and the strength of a tumble flow. The figure which shows the state at the time of the process of the boundary of the wall surface of an intake port, and a throat part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake port 2a Wall surface on the opposite side with respect to the side into which the intake air which forms a tumble flow is introduced in the arrangement direction of each intake port 3 Cylinder 6 Valve seat 6a Throat part 7 Edge 8 R T Tumble flow

Claims (2)

Two intake ports are provided side by side with respect to one cylinder, and each intake port is an internal combustion engine configured to direct intake air to the cylinder so as to form a tumble flow in the cylinder,
At the boundary between the wall surface of the intake port and the wall surface on the inner side of the intake ports in the arrangement direction and opposite to the side where the intake air forming the tumble flow is introduced, and the throat portion of the valve seat connected to the intake port An internal combustion engine characterized in that an edge is formed and a smooth radius is formed at a boundary between the wall surface of the intake port and the throat portion other than the boundary where the edge is formed. Two intake ports are provided side by side with respect to one cylinder, and each intake port is an internal combustion engine configured to direct intake air into the cylinder so that a normal tumble flow is formed in the cylinder. And
An edge is formed at a boundary between a wall surface of the intake port on the inner side in the arrangement direction of each intake port and located on the outer periphery of the cylinder and a throat portion of the valve seat connected to the intake port, and the intake port An internal combustion engine having a smooth round shape except the boundary where the edge is formed among the boundary between the wall surface and the throat portion.

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