JPS58204933A - Helical intake port - Google Patents

Abstract

PURPOSE:To generate a strong swirl flow when an engine is operated at a low speed with a small load, by forming the inside of a volute part side wall neighboring to the outlet of a branch path from a downward facing sloped surface. CONSTITUTION:When an engine is operated at a low speed and low load with a small amount of intake air, a rotary valve 25 closes a branch path 24. As the first side wall face 14a of a partition 12 is extended to a part in the vicinity of a side wall face 15 of a volute part B, a mixture flowing to advance along an upper wall face 20 is forcibly moved onto the side wall face 15 of the volute part B, and said mixture flows along the side wall face. Then if said mixture reaches the side wall face part 15a, the mixture is turned while its flow direction is deflected facing downward because said side wall face part 15a is formed by a downward facing sloped surface. If the flow direction is deflected downward, this mixture flows not to collide with the partition 12 and is supplied while turning into a combustion chamber 4.

Description

[Detailed description of the invention] The present invention relates to a helical intake port.

A helical intake port usually includes a spiral portion formed on the side of the intake valve, and an inlet passage portion that is tangentially connected to the spiral portion and extends substantially straight. When trying to generate a strong swirling flow in the combustion chamber of an engine using such a helical type air intake when the engine is operating at low speed and low load with a small amount of intake air, the shape of the intake port becomes a shape that has a large flow resistance. This causes a problem in that charging efficiency decreases when the engine is operated at high speed and under high load with a large amount of intake air. To solve this problem, we formed a branch passage in the cylinder head that branches from the helical intake port inlet passage and communicates with the spiral end of the helical intake port spiral part, and installed an on-off valve in the branch passage. The applicant has already proposed a helical intake port in which an on-off valve is opened during high-speed, high-load engine operation. In this helical type intake port, when the engine is operated at high speed and under high load, the negative part of the intake air sent into the helical type intake port inlet passage is sent into the spiral part of the helical type intake port through a branch passage, so the intake air is drawn into the helical type intake port. The cross-sectional area of the air flow path is increased, and thus the filling efficiency can be improved. However, in this helical intake port, the branch passage is formed as a cylindrical passage completely independent from the inlet passage, so the flow resistance of the branch passage is relatively large, and the branch passage is formed adjacent to the inlet passage. This limits the cross-sectional area of the inlet passage, making it difficult to obtain a sufficiently high filling efficiency. Furthermore, the helical intake port itself has a complicated shape, and if a branch passage that is completely independent from the inlet passage is added, the overall structure of the intake port will become extremely complicated. It is difficult to form a helical intake port in the cylinder head.

SUMMARY OF THE INVENTION The present invention provides a helical intake port which is capable of achieving high filling efficiency during engine high-speed, high-load operation and has a new shape that is easy to manufacture.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Referring to FIGS.
3 is a cylinder pro, the cylinder head is fixed on the cylinder head 1, 4 is a combustion chamber formed between the piston 2 and the cylinder head 3, 5 is an intake valve, and 6 is a helical intake formed in the cylinder head 3. 7 is an exhaust valve, 8 is a horizontal air port formed in the cylinder head 3, 9 is a spark plug arranged in the combustion chamber 4, and 10 is a stem guide that guides the stem 5a' of the intake valve 5. Show each. As shown in FIGS. 1 and 2, a partition wall 12 projecting downward is integrally formed on the upper wall surface 11 of the intake port 6, and this partition wall 12 forms a tangent to the spiral portion B of the A helical intake valve is formed by an inlet passage section A connected to the intake passage A. This partition wall 12 extends from inside the inlet passage part A to around the stem guide 10 of the intake valve 5, and as can be seen from FIG. It is narrow and uniform from the narrowest part to the vicinity of the stem guide 10, and becomes widest around the circumference of the stem guide 10. The partition wall 12 is the inlet opening 6a of the intake port 6.
The partition wall 12 further has a first side wall surface 14m extending counterclockwise from the tip 13 in FIG.
(b) A second side wall surface 14b extending in (b) (b). The first side wall surface 141 extends from the distal end portion 13 through the side of the stem guide 10 to the vicinity of the side wall surface 15 of the spiral portion B, and forms a narrow portion 16 between the first side wall surface 141 and the spiral portion side wall surface 15 . On the other hand, the distance between the second side wall surface 14b and the first side wall surface 14& increases from the tip end 13 toward the stem guide 10, and then the distance between the second side wall surface 14b and the first side wall surface 14m becomes approximately uniform. Extends to. Next, this second side wall surface 14b is connected to the stem guide 10.
The oil extends around the outer periphery of the tube and reaches the narrowed portion 16.

Referring to FIGS. 1 to 9, one side wall surface 17 of the inlet passageway portion A is arranged substantially vertically, and the other side wall surface 18 is formed from a slightly inclined downwardly inclined surface. On the other hand, the earthen wall surface 19 of the entrance passage section A descends toward the spiral section B and is smoothly connected to the upper wall surface 20 of the spiral section B. The upper wall surface 20 of the spiral portion B gradually narrows in width while descending from the connecting portion between the spiral portion B and the inlet passage portion A toward the narrowing portion 16, and then gradually widens after passing through the narrowing portion 1fl1. on the other hand,
The side wall surface 17 of the entrance passage section A is smoothly connected to the side wall surface 15 of the spiral section B, and the bottom wall surface 21 of the entrance passage section A is connected smoothly to the side wall surface 15 of the spiral section B.
descend towards.

On the other hand, the first side wall surface 14m of the partition wall 12 is a slightly downwardly inclined surface, and the second side wall surface 14b is substantially vertical. The bottom wall surface 22 of the partition wall 12 includes a first bottom wall surface portion 22m extending from the tip 13 of the partition wall 12 to the vicinity of the stem guide 10, and a second bottom wall surface portion 22b located around the circumference of the stem guide 10. The first bottom wall surface portion 22 extends substantially parallel to the top wall surface 19 to near the bottom wall surface 210. On the other hand, the second bottom wall surface portion 22 measured from the soil wall surface 19
The height of b is lower than the height of the first bottom wall surface portion 22m, and the distance between the second bottom wall surface portion 22b and the upper wall surface 19 gradually decreases toward the narrowed portion 16. Further, a rib 23 that projects downward is formed on the @2 bottom wall surface portion 22b in a region indicated by hatching in FIG. 4, and the rib 23 extends from the first bottom wall surface portion 22m to the narrowed portion 16. As shown in FIG. 8, the second bottom wall surface portion 22b descends toward the rib 23.

On the other hand, inside the cylinder head 3, there is a spiral end portion C of the spiral portion B.
A branch path 24 is formed that communicates the inlet passage section A with the inlet passage section A, and a rotary valve 25 is disposed at the inlet of this branch path 240.

This branch passage 24 is separated from the inlet passage part A by the partition wall 12, and the entire lower space of the branch passage 24 communicates with the inlet passage part A. The upper wall surface 26 of the branching path 24 has a uniform width, and descends toward the spiral end portion C to form the spiral portion B.
It is smoothly connected to the upper wall surface 20 of. In addition, as shown in FIG. 7, the height Hl of the top wall surface 26 of the bottom wall surface 21 or the falconry branch path 24 is the height Hl of the top wall surface 19 of the entrance passage section A,
It is higher than that. The side wall surface 27 of the branch passage 24 facing the second side wall surface 14b of the partition wall 12 is substantially vertical, and the bottom wall surface portion 21m below the branch passage 24 is raised to form an inclined surface. This inclined bottom wall surface portion 21a is the first
As shown in the figure, it extends from the vicinity of the inlet opening 6a of the intake port 6 to the spiral portion B. On the other hand, Figures 1, 4 and 8
As can be seen from the figure, the side wall surface portion 15a of the spiral portion B near the exit of the branching path 24 is formed into a slightly sloped downward surface, and the second side wall surface 14b of the partition wall 12 has a sloped side wall surface portion. It extends toward 15a. Therefore, a second narrowed portion 16a is formed between the second side wall surface 14b and the inclined side wall surface portion 15a.

As shown in FIG. 9, the rotary valve 25 is composed of a rotary valve holder 28 and a valve shaft 29 rotatably supported within the rotary valve holder 28.
The valve holder 28 is attached to the cylinder 21,,stc*ystu
l:taea3on<5ash, b.

A thin plate-like valve body 31 is integrally formed at the lower end of the valve shaft 29, and as shown in FIG. 1, this valve body 31 extends from the top wall surface 26 of the branch passage 24 to the bottom wall surface 21. On the other hand, the valve stem 29
An arm 32 is fixed to the upper end of. In addition, the valve shaft 29
A ring groove 33 is formed on the outer peripheral surface of the ring groove 33, and an E-shaped positioning ring 34 is fitted into the ring groove 33. Further, a seal member 35 is fitted to the upper end of the rotary valve holder 28, and the seal member 35 performs a sealing action on the valve shaft 29.

Referring to the diagram, the tip of the arm 32 fixed to the upper end of the rotary valve 25 is connected to the negative pressure diaphragm device 4
It is connected to a control rod 42 fixed to a diaphragm 41 of No. 0 through a connecting rod 43t. The negative pressure diaphragm device 40 has a negative pressure chamber 44 isolated from the atmosphere by a diaphragm 41, and a compression spring 45 for pressing the diaphragm is inserted into the negative pressure chamber 44. An intake manifold 47 equipped with a compound carburetor 46 consisting of a primary carburetor 46m and a secondary carburetor 46b is attached to the cylinder head 3, and the negative pressure chamber 44 is connected to the intake manifold 47 via a negative pressure conduit 48. connected within. A check valve 49 is inserted into the negative pressure conduit 48 and allows flow only from the negative pressure chamber 44 into the intake manifold 47 . Further, the negative pressure chamber 44 communicates with the atmosphere via an atmosphere conduit 50 and an atmosphere release control valve 51.

This atmospheric release control valve 51 has a negative pressure chamber 53 and an atmospheric pressure chamber 54 separated by a diaphragm 52, and further has a valve chamber 55 in instant contact with the atmospheric pressure chamber 54. This valve chamber 55 communicates with the negative pressure chamber 44 via an atmospheric air conduit w50 on the one hand, and with the atmosphere via a valve port 56 and an air filter 57 on the other hand.

Inside the valve chamber 55 is a valve body 58 that controls opening and closing of the valve port 56.
The valve body 58 is connected to the diaphragm 52 via a valve rod 59. A compression spring 60 for pressing the diaphragm is inserted into the negative pressure chamber 53, and the negative pressure chamber 53 is further connected to the pentagonal portion 62 of the primary side carburetor 46m via a negative pressure conduit 61.

The carburetor 46 is a commonly used carburetor, and when the primary throttle valve 63 opens a predetermined opening degree or more, the secondary throttle valve 64 opens, and when the primary throttle valve 63 fully opens, the secondary throttle valve 64 opens. The side throttle valve 64 is also fully opened. The negative pressure generated in the venturi section 62 of the primary side carburetor 46 increases as the amount of intake air supplied into the engine cylinder increases. When the pressure increases, that is, when the engine is operated at high speed and high load, the diaphragm 52 of the atmospheric release control valve 51 releases the compression spring 6.
0, and as a result, the valve body 58 opens the valve port 56 and opens the negative pressure chamber 44 of the negative pressure diaphragm device 40.
open to the atmosphere. At this time, the diaphragm 41 moves downward (by the spring force of the compression spring 45), and as a result, the rotary valve 25 is rotated and the branch passage 24 is fully opened. On the other hand, when the opening degree of the primary throttle valve 63 is small, the negative pressure generated in the venturi section 62 is small, so the diaphragm 52 of the atmospheric release control valve 51 moves to the left by the spring force of the compression spring 60. , the valve body 58 closes the valve □ port 56. Furthermore, when the opening degree of the primary throttle valve 63 is small as described above, a large negative pressure is generated within the intake manifold 47. The check valve 49 is configured so that the negative pressure inside the intake manifold 4 is connected to the negative pressure diaphragm device 40.
The valve opens when the negative pressure in the negative pressure chamber 44 becomes greater than the negative pressure in the negative pressure chamber 44, and the negative pressure in the intake manifold 47 also exceeds the negative pressure in the negative pressure chamber 44.
Since the valve closes when the temperature drops, the negative pressure in the negative pressure chamber 44 is transferred to the intake manifold 47 when the atmospheric release control valve 51 is closed.
maintained at the maximum negative pressure generated within. When negative pressure is applied within the negative pressure chamber 44, the diaphragm 41 rises against the compression spring 45, and as a result, the rotary valve 25 is rotated and the branch passage 24 is closed. Therefore, when the engine is operating at low speed and low load, the rotary valve 25 closes the branch passage 24. Note that when the engine speed is low even during high-load operation, or when low-load operation is performed even when the engine speed is high, the negative pressure generated in the venturi section 62 is small, so it is not released to the atmosphere. Control valve 51 remains closed. Therefore, during such low-speed, high-load operation and high-speed, low-load operation, the branch passage 24 is closed by the rotary valve 25 because the negative pressure in the negative pressure chamber 44 is maintained at the maximum negative pressure of □ 1 mentioned above. has been done.

As described above, the rotary valve 25 closes the branch passage 24 when the engine is operated at low speed and under low load with a small amount of intake air. At this time, part of the air-fuel mixture sent into the inlet passage section A travels along the earth wall surface 19.20, and part of the remaining air-fuel mixture collides with the rotary valve 25. Inlet passage section A
After changing its direction toward the side wall surface 17 of the spiral portion B, it moves toward the side wall surface 15 of the spiral portion B. As mentioned above, the width of the upper wall surface 19.20 gradually becomes narrower as it approaches the narrowed part 16, so the flow path for the air-fuel mixture flowing along the earth wall surface 19.20 becomes gradually narrower. The mixture flow along 19.20 is gradually accelerated. Furthermore, as described above, since the first side wall surface 14 & of the partition wall 12 extends to the vicinity of the side wall surface 15 of the spiral portion B, the air mixture flowing along the upper wall surface 19 r 20KG is pushed onto the side wall surface 15 of the spiral portion B. As a result, this air-fuel mixture overflows onto the side wall surface 15 and advances. Next, when this air-fuel mixture reaches the 1i11J wall surface portion 15m, since this side wall surface portion 15m is formed from a downwardly inclined surface as described above, the air-fuel mixture swirls and its flow path direction is deflected downward. When the flow path direction of the mixture is deflected downward in this manner, the mixture flow is supplied into the combustion chamber 4 while swirling without colliding with the partition wall 12. Therefore, the swirling flow generated in the swirl portion B is supplied into the combustion chamber 4 without being weakened, so that a strong swirling flow is generated in the combustion chamber 4.

On the other hand, when the engine is operated at high speed and under high load with a large amount of intake air i/l, the rotary valve 25 is opened, so that the air-fuel mixture sent into the inlet passage A is roughly divided into three streams. That is, the first flow is a mixed air flow that flows between the first side wall surface 14m of the partition wall 12 and the side wall surface 17 of the inlet passage section A, and then flows while swirling at the soil wall surface 20VcG of the spiral section A. The second flow is a mixed air flow that flows into the swirl part B via the branch passage 24), and the third flow is a mixture flow that flows into the bottom wall surface 21 of the inlet passage part A.
This is the mixed air flow that flows into the swirl portion B.

The flow resistance of the branch path 24 is between the first side wall surface 14m and the side wall surface 17.
Therefore, the flow resistance of the second air mixture flow is smaller than that of the first air mixture flow.

Furthermore, since the second constriction part 16a is formed at the outlet of the branch passage 24, the second air mixture flow flowing in from the branch passage 24 has a flow velocity increased when passing through the second constriction part 16m, and then The second mixed gas flow collides obliquely with the upper side of the first mixed gas flow swirling along the side wall surface 15 of the swirl portion B, thereby deflecting the flow direction of the first mixed gas flow downward. In this way, a large amount of air-fuel mixture is supplied from the branch passage 24 with low flow resistance,
Furthermore, since the flow direction of the first mixed gas flow is deflected downward, high filling efficiency can be obtained.

Further, in the helical A/type intake port according to the present invention, since the partition wall 12 may be entirely integrally molded on the upper wall surface of the intake port b, the helical type intake port can be easily manufactured.

As described above, according to the present invention, when the engine is operating at low speed and low load, the branch passage is shut off and a large amount of air-fuel mixture is transferred to the upper wall surface K of the volute part.
A strong swirling flow can be generated in the combustion chamber by deflecting the flow direction of the mixed gas flow, which then flows while swirling against the side wall surface of the volute part, downward by the downwardly inclined side wall surface portion. can. On the other hand, high-speed engine (15)... bulkhead, 24... branching path, 25... rotary valve.

During loading operation, by opening the branch passage, a large amount of air-fuel mixture flows and is sent into the volute through the branch passage with low resistance, and the flow direction of the swirling mixture is the mixture flow that flows in from the branch passage. Since it is deflected downward, high filling efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a 0i11 cross-sectional view of the internal combustion engine according to the present invention taken along line if in FIG. 2, and FIG.
3 is a side view schematically showing the shape of the helical intake port according to the present invention; FIG. 4 is a plan view schematically showing the shape of the helical intake port;
Figure 5 is a cross-sectional view taken along the line ■-■ in Figure 3, Figure 6 is a cross-sectional view taken along the line ■-■ in Figure 3, and Figure 7 is a cross-sectional view taken along the line ■-■ in Figure 3.
Figure 8 is a cross-sectional view taken along the line ■-■ in the figure, and Figure 8 is a cross-sectional view of the rotary valve. It is a diagram showing a drive control device. 4... Combustion chamber, 6... Helical intake port, 12
(16) Patent Applicant Toyota Motor Corporation Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Akira Yamaguchi

Claims (1)

[Claims] In a helical intake port configured with a spiral formed around the intake valve and an inlet passage connected tangentially to the spiral and extending almost straight, the spiral is branched from the inlet passage. A branch passage communicating with the spiral terminal end of the part is provided in the inlet passage part, and the branch passage is separated from the inlet passage part by a partition wall that projects downward from the upper wall surface of the intake port and extends from the inlet passage part to the periphery of the intake valve stem. The entire lower space of the branch passage communicates with the inlet passage portion in the cross section, and the passage walls of the inlet passage portion and the branch passage are integrally connected, and an on-off valve is provided in the branch passage. A helical intake port in which the intake air flow flowing through the branch passage is controlled by the on-off valve, and the side wall surface of the spiral portion adjacent to the outlet of the branch passage is formed from a downwardly inclined surface.