JPS58204930A - 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 expansibly forming the side wall face of a volute part toward an intake valve stem in the connection part between the side wall face of the volute part and the side wall face of a branch path. CONSTITUTION:At low speed and low load operation of an engine with a small amount of intake air, a rotary valve 25 closes a branch path 24. Since 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 is forcibly moved onto the side wall face 15 of the volute part B, then the mixture advances along the face 15 and its flow path is curved to the direction of an intake valve stem 5a by a side wall face part 15a. Accordingly, a strong swirl flow is generated in the volute part B. Then the mixture performs a turning motion while flows in through a gap formed between an intake valve 5 and its valve seat, and a strong swirl flow can be generated in a combustion chamber 4.

Description

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

A helical intake port is usually composed of a spiral portion formed in the intake valve layer and an inlet passage portion that is tangentially connected to the spiral portion and extends substantially straight. If you try to use a helical intake port to generate a strong swirling flow in the combustion chamber of the engine during low-speed engine load operation with a small amount of intake air, the shape of the intake port will have a large flow resistance. A problem arises in that charging efficiency decreases during high-speed, high-load operation of the engine with a large amount of fuel.

In order to solve this problem, a branch path is formed in the cylinder head that branches off from the helical intake port inlet passage and communicates with the spiral end of the helical intake port spiral section, and an on-off valve is installed in the branch path. 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, a part of the intake air sent into the helical type intake port inlet passage is sent into the helical type intake port spiral part through a branch path, so the intake air flow path is The cross-sectional area can be increased, thus improving the filling efficiency.

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 quite difficult to form a helical intake port in a cylinder head.
・□″The object of the present invention is to provide a helical intake port that can obtain 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 FIG. 1 and FIG. 2, 1 is a cylinder block, 2 is a piston that reciprocates within the cylinder block 1,
3 is a cylinder head fixed on the cylinder block 1; 4 is a combustion chamber formed between the piston 2 and the cylinder head 3; 5 is an intake valve; 6 is a helical intake port formed within the cylinder head 3; 7 is an exhaust valve, 8 is an exhaust port formed in the cylinder head 3, 9 is an ignition plug arranged in the combustion chamber 4, and 10 is a stem guide for guiding the stem 5a of the intake valve 5, respectively. 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 connects a spiral portion B and a tangential line to this spiral portion B. A helical intake port 6 consisting of connected inlet passage portions A is formed. This partition wall 1211: extends from inside the inlet passage A to around the stem guide 10 of the intake valve 5, and as shown in FIG.
The width of the root part of 2 is narrowest on the side closest to the entrance passage part A.
It is almost uniform from this narrowest part to the vicinity of the stem guide 10, and becomes widest around the circumference of the stem guide 10. The bulkhead 12 has a distal end 13 located on the side closest to the inlet opening 6a of the intake port 6, and the septum 12 further has a first side wall surface 1. extending counterclockwise from the distal end 13 in FIG.
4a, and a second side wall surface 14b extending clockwise from the tip portion 13. The first side wall surface 14a passes from the distal end portion 13 to the side of the stem guide 10 to the side wall surface 15 of the spiral portion B.
A narrow portion 16 extends to the vicinity of the spiral portion side wall surface 15.
form. On the other hand, the second side wall restraint 14b is arranged so that the distance from the first side wall surface 14a increases from the tip end 13 toward the stem guide 10, and then the distance from the first side wall surface 141 becomes almost uniform. Extends to. Next, this second side wall surface 14b extends along the outer periphery of the stem guide 10 and reaches the narrowest portion 16.

Referring to FIGS. 1 to 9, one side wall surface 17Fi of the inlet passage A is arranged substantially vertically, and the other side wall surface 18 is formed as a slightly downwardly inclined surface.

On the other hand, the upper wall surface 19 of the inlet 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 narrows in width.

After passing through the narrowing part 16, the width gradually increases. On the other hand, the side wall surface 17 of the inlet 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 descends toward the spiral section B.

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 consists of a first bottom wall surface portion 22 & 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 stem guide 10. The first bottom wall surface portion 22m is substantially parallel to the top wall surface 19 and extends close to the bottom wall surface 21. On the other hand, the second bottom wall surface portion 22 measured from the top wall surface 19
The height b is lower than the height of the first bottom wall surface portion 22a, and furthermore, 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 lip 23 projecting downward is formed on the second bottom wall surface portion 22b in a region indicated by hatching in FIG. 4, and this lip 23 extends from the first bottom wall surface portion 22a to the narrowed portion 16. As shown in FIG. 8, the second bottom wall surface portion 22b descends toward the lip 23.

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

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 earthen wall surface 26 of the branching path 24 has a substantially uniform width, descends toward the spiral terminal end C, and smoothly connects to the upper wall surface 20 of the spiral section B. In addition, as shown in FIG. 7, the upper wall surface 2 of the branch road 24 measured from the bottom wall surface 21
6 is higher than the height H2 of the upper wall surface 19 of the entrance passage section A. A side wall surface 27 of the branch path 24 facing the second side wall surface 14b of the partition wall 12 is substantially vertical, and a bottom wall surface portion 21a below the branch path 24 is raised to form an inclined surface. This inclined bottom wall surface portion 211 extends from the vicinity of the inlet opening 6a of the intake port 60 to the spiral portion B, as shown in FIG. On the other hand, as can be seen from FIGS. 1, 4, and 8, the side wall surface portion 15m of the spiral portion B near the outlet of the branching path 24 is formed into a slightly inclined downward slope. The wall surface portion 15& is bulged toward the intake valve stem 5a compared to the other spiral portion side wall surfaces 15.

Further, this side wall surface portion 15a is smoothly connected to the spiral portion side wall surface 15, and furthermore, this side wall surface portion 15a is connected to the second spiral portion side wall surface 15.
As shown in the figure, it forms an arc with a radius R. On the other hand, the second side wall surface 14b of the partition wall 12 projects toward this inclined side wall surface portion 15a. Therefore, a second narrowed portion 16m is formed between the second side wall surface 14b and the inclined side wall surface portion 15a! will be accomplished.

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 rotary valve holder 28 is bored into the cylinder head 3. Installed screw hole 3
It is screwed into the 0.

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 FiE-shaped positioning ring 34 is fitted into the ring groove 33.

Furthermore, a sealing member 35 is provided at the upper end of the rotary valve holder 28.
is fitted, and this sealing member 35 performs a sealing action on the valve shaft 29.

Referring to FIG. 10, the tip of the arm 32 fixed to the upper end of the rotary valve 25 is connected to a negative pressure diaphragm device 40.
It is connected via a connecting rod 43 to a control rod 42 fixed to a diaphragm 41 of. 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. 1 for cylinder head 3
An intake manifold 47 equipped with a conno-Q round type carburetor 46 consisting of a next side carburetor 46& and a second side carburetor 46b is attached, and the negative pressure chamber 44 is connected to the inside of the intake manifold 47 via a negative pressure conduit 48. Ru. 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 . Furthermore, the negative pressure chamber 44i1 is communicated 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 adjacent to the atmospheric pressure chamber 54. This valve chamber 55 communicates with the negative pressure chamber 44 via an atmospheric conduit 50 on the one hand;
On the other hand, it communicates with the atmosphere via a valve port 56 and an air filter 57.

Inside the valve chamber 55 is a valve body 58 that controls the opening and closing of the valve J-) 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 a venturi portion 62 of the primary side carburetor 46a 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 The next throttle valve 64 is also fully opened. The negative pressure generated in the venturi section 62 of the primary side carburetor 4'6a increases as the amount of intake air supplied into the engine cylinder increases. When the pressure increases, that is, when the engine is operating at high speed and high load, the diaphragm 52 of the atmospheric release control valve 51 moves to the right against the compression spring 60, and as a result, the valve body 58 opens the valve port 56 and the negative The negative pressure chamber 44 of the pressure diaphragm device 40 is opened to the atmosphere. At this time, the diaphragm 41 moves downward due to the spring force of the compression spring 45, and as a result -
The tarry valve 25 is rotated to open the branch path 24.

On the other hand, 1.1:...: When the opening degree of the next 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 is moved 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 opens when the negative pressure inside the intake manifold 47 increases as well as the negative pressure inside the negative pressure chamber 44 of the negative pressure diaphragm device 40, and the negative pressure inside the intake manifold 47 increases when the negative pressure inside the negative pressure chamber 44 increases. Since the valve closes when the pressure becomes smaller than the negative pressure, the negative pressure in the limited negative pressure chamber 44 where the atmospheric release control valve 51 is closed is maintained at the maximum negative pressure generated in the intake manifold 47.

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 path 24.
will be closed. In addition, even during high load operation, if the engine speed is low, ', ', 'l, ', '
, l, l'l'1 Even if the engine speed is high, when low load operation is performed, the atmospheric release cutoff valve 51 remains closed because the negative pressure generated in the venturi portion 62 is small. Therefore, during such low-speed, high-load operation and high-speed, low-load operation, the negative pressure in the negative pressure chamber 44 is maintained at the aforementioned maximum negative pressure, so the branch passage 24 is closed by the rotary valve 25.

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 advances along the upper wall surface 19,20, and part of the remaining air-fuel mixture collides with the rotary valve 25 and passes through the inlet passage. Part A
After changing its direction toward the side wall surface 17 of the spiral portion B, it proceeds along the side wall surface 15 of the spiral portion B. As described above, the width of the upper wall surface 19.20 gradually becomes narrower as it approaches the narrowed portion 16, so that the flow path for the air-fuel mixture flowing along the upper wall surface 19.20 gradually narrows. The air mixture flow along 20 is gradually accelerated. Furthermore, as described above, the first side wall surface 14a of the partition wall 12 extends to the vicinity of the side wall surface 15 of the spiral portion B, so that the air mixture flowing along the earth wall surface 19.20 flows onto the side wall surface 15 of the spiral portion B. pushed away, then side wall surface 15
The intake valve stem 5 is then moved along the side wall surface portion 15a.
The flow path is further bent toward point a. Therefore, the spiral part B
A strong swirling flow is often generated within the tank. Next, the air-fuel mixture swirls and flows into the combustion chamber 4 through the gap formed between the intake valve 5 and its valve seat, generating a strong swirling flow within the combustion chamber 4. In this way, the side wall surface portion 15
By forming a, it is possible to give further swirling force to the air mixture flowing along the side wall surface 15 of the spiral part, and it is also possible to prevent this air mixture from flowing into the branch passage 24 and attenuating the swirling force. A swirling flow can be generated.

On the other hand, when the engine is operated at high speed and under high load with a large amount of intake air, 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 flows between the first side wall surface 14a of the partition wall 12 and the side wall surface 17 of the inlet passage section A, and then flows into the upper wall surface 2 of the spiral section A.
0, the second flow is a mixture 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 swirl part B through the branch passage 24. This is a mixed air flow that flows into the swirl portion B along the .

The flow resistance of the branch path 24 is caused by the first side wall surface 14a 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.

Further, since a second constriction part 16a is formed at the outlet of the branch passage 24, the air-fuel mixture flowing in from the branch passage 24 has a flow velocity increased when passing through the second constriction part 16a, and then this mixture is swirled. The first mixed gas flow obliquely collides with the upper side of the first mixed gas flow, causing the first mixed gas flow to be deflected 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 type intake port according to the present invention, the partition wall 12 may be integrally formed on the upper wall surface of the intake port 6, so that 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 to allow a large amount of air-fuel mixture to flow along the soil wall surface of the volute, and then the mixture flow flows along the side wall surface of the volute. By further deflecting the direction inward by the inwardly bulging side wall portion, a strong swirling flow can be generated within the combustion chamber. On the other hand, during engine high-speed, high-load operation, by opening the branch passage, a large amount of air-fuel mixture flows into the volute through the branch passage with low resistance, and the flow direction of the swirling mixture flows into the swirling part from the branch passage. Since it is deflected downward by the airflow, high filling efficiency can be obtained.

[Brief explanation of drawings]

1 is a side sectional view of an internal combustion engine according to the present invention taken along the line II in FIG. 2, FIG. 2 is a sectional plan view taken along the line ■-■ in FIG. 1, and FIG. 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, and FIG. 6 is a sectional view taken along line M--■ in FIG. 3, FIG. 7 is a sectional view taken along line 3--■ in FIG. FIG. 9 is a side sectional view of the rotary valve, and FIG. 10 is a diagram showing a drive control device for the rotary valve. 4... Combustion chamber, 6... Helical intake port, 12
... Partition wall, 15 ... Side wall, 15a ... Side wall surface portion, 24 ... Branch passage, 25 ... Rotary valve. Patent applicant Toyota Motor Corporation Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Kyo Nakayama Patent attorney Akira Yamaguchi Figure 4 Figure 7 Figure 8

Claims (1)

[Claims] In a helical intake port configured with a spiral part formed in the intake valve part and an inlet passage part connected tangentially to the spiral part and extending almost straight, the spiral part is branched from the inlet passage part. A branch passage communicating with the spiral terminal end of the inlet passage is provided alongside the inlet passage, and the branch passage is separated from the inlet passage by a partition wall that projects downward from the upper wall surface of the intake port and extends from the inlet passage to around the intake valve stem; The entire lower space of the branch passage communicates with the inlet passage part in a cross section, and the passage wall of the inlet passage part and the branch passage are integrally connected, and an on-off valve is provided in the branch passage. Controlling the intake air flow flowing in the branch path by the on-off valve,
Furthermore, the helical type intake port has the spiral portion side wall surface bulged toward the intake valve stem at the connection portion between the spiral portion side wall surface and the branch road side wall surface.