JPS58204926A - Helical intake port - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Helical intake? -F is usually constituted by a spiral portion formed around the intake valve and an inlet passage portion that is tangentially connected to the spiral portion and extends substantially straight. If you try to use such a helical intake port to generate a strong swirling flow in the combustion chamber of the engine during low-speed, low-load operation of the engine with a small amount of intake air, the shape of the intake port will have a large flow resistance. This causes a problem in that the filling efficiency decreases when the engine is operated at high speed and under high load with a large amount of intake air. In order to solve this problem, a branch path is formed 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 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 volute via the branch path, so that the intake air is The cross-sectional area of the flow path is increased, thus making it possible to improve 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 it may be difficult to connect the branch passage 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 with a channel in a cylinder head.

SUMMARY OF THE INVENTION The present invention provides a helical intake port which is capable of achieving high filling efficiency during high-speed, high-load engine 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 5& of the intake valve 5, respectively. As shown in FIGS. 1 and 2, a partition wall 12 projecting downward is integrally molded on the soil wall surface ll of the intake port 6, and this partition wall 12 forms a tangent to the spiral portion B of the A helical intake port 6 consisting of an inlet passage section A connected to is formed. 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 narrowest at the side, is almost uniform from this narrowest part to the vicinity of the stem guide 10, and becomes widest around the stem guide 100. The partition 12 has a tip 13 located on the side closest to the inlet opening 6a of the intake port 6, and the partition 12 further has a first side wall surface 141 extending counterclockwise from the tip 13 in FIG. It has a second side wall surface 14b extending clockwise from the portion 13. The first side wall surface 14a 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 14a and the spiral portion side wall surface 15. On the other hand, from the tip 13 of the second side wall surface 14bld toward the stem guide IO, the distance between the first side wall surface 14m and the first side wall surface 14m increases, and then the first side wall surface 1
It extends so that the distance from 4m is almost uniform. This second side wall surface 14b then extends along the outer periphery of the stem guide 10 and reaches the narrowed portion 16.

Referring to FIGS. 1-9, one side wall surface 17 of the inlet passageway is generally vertically disposed, and the other side wall surface 18 is formed from a slightly sloped downward slope. On the other hand, the upper wall surface 19 of the entrance passage member descends toward the spiral portion B and is smoothly connected to the upper wall surface 20 of the spiral portion B. The earth 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 narrowed portion 16, and then gradually widens after passing through the narrowed portion 16. 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 14& 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 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 on the circumference of the stem guide 10. The first bottom wall surface portion 221 is substantially parallel to the earth 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 of 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 becomes smaller 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 221 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 with the inlet passage section and the inlet passage section, and a rotary valve 25 is disposed at the entrance of this branch passage 240.

This branch passage 24 is separated from the entrance passage section by the partition wall 12, and the entire space below the branch passage 24 communicates with the entrance passage section A. The upper wall surface 26 of the branch passage 24 has a substantially uniform width, descends toward the spiral terminal end C, and is smoothly connected to the upper wall surface 20 of the spiral section B. In addition, as shown in FIG. 7-1, the height Hl of the top wall surface 26 of the bottom wall surface 215"p/nine branch passageway 24 is higher than the height of the upper wall surface 19 of the entrance passage section A. The side wall surface 27 of the branch channel 24 facing the second side wall surface 14b of the partition wall 12 is substantially vertical, and the bottom wall surface portion 21a below the branch channel 24 is raised to form an inclined surface. Bottom wall part 21
A extends from the vicinity of the inlet opening 6a of the intake port 6 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 151L of the spiral portion B near the outlet of the branching path 24 is formed into a slightly inclined downward slope, and The second side wall surface 14b projects toward this inclined side wall surface portion 15a. Therefore, there is a second
A narrowed portion 16 & is formed.

As shown in FIG. 9, it is composed of a rotary valve holder 28 for 25 rotary valves, and a valve shaft 29 rotatably supported within the rotary valve holder 28, and this rotary valve holder 28 is inserted into the cylinder i''.

- It is drilled into the door 3 and screwed into the screw hole 30.

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. On the other hand, a conical groove 36 is formed on the inclined bottom wall surface portion 211 facing the lower end of the valve body 31 , and the lower end of the valve body 31 enters into the conical groove 36 . Furthermore, as shown in FIG. 6 and FIG.
surrounded by. In this cooling water passage 38, from the cooling water passage in the cylinder block 1 to the arrow P in FIG.
, Q, the cooling water flows in.

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 rad 3
An intake manifold 47 is installed which includes a conno-branch type carburetor 46 consisting of a downstream carburetor 46m and a secondary carburetor 46b, and the negative pressure chamber 44 is connected to the intake manifold 47 via a negative pressure conduit 48. be done. 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 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 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 a venturi portion 62 of the primary side carburetor 46& through 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 next throttle valve 64 is also fully opened. The negative pressure generated in the venturi section 62 of the primary side carburetor 46a increases as the amount of intake air supplied into the engine cylinder increases. Therefore, the negative pressure generated in the venturi section 62 becomes larger than a predetermined negative pressure. In other words, when the engine is operating 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.
Release large tuna. At this time, the diaphragm 41 is moved 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 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 moves to the left by the spring force of the compression spring 60, and the valve body 58 closes 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 anifold 47. The check valve 49 opens when the negative pressure in the intake manifold 47 becomes larger than the negative pressure in the negative pressure chamber 44 of the negative pressure diaphragm device 40, and the negative pressure in the intake manifold 47 becomes larger than that in the negative pressure chamber 44. Since the valve closes when the negative pressure decreases, the negative pressure in the negative pressure chamber 44 is maintained at the maximum negative pressure generated in the intake manifold 47 as long as the atmospheric release control valve 51 is closed.

When negative pressure is applied to the negative pressure chamber 44, the diaphragm 41 rises against the compression spring 45, and as a result, the rotary valve 25 is rotated 11 degrees 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. Shutoff valve 51 remains closed. 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 mentioned above, the rotary valve 25 closes the branch passage 24 when the engine is operated at low speed and 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. Inlet passage section 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. Further, at this time, the air mixture flowing toward the rotary valve 25 along the bottom wall surface 21 of the inlet passage section A is forced toward the side wall surface 17 of the inlet passage section A because of the inclined side wall section 21a. In this way, this air-fuel mixture flows into the swirl portion B without being drawn into the branch passage 24 downstream of the rotary valve 25. If the mixture flow flows into the branch passage 24, this mixture will not only not contribute to the generation of the swirling flow, but will also generate turbulence within the branch passage 24, and this turbulence will attenuate the swirling flow. Therefore, the swirling flow generated in the swirl portion B is weakened. Therefore, in the present invention, in order to prevent the air-fuel mixture from flowing into the branch passage 24 downstream of the rotary valve 25, the inclined side wall portion 21a is provided below the branch passage 24.
I am trying to set it up.

On the other hand, as mentioned above, the width of the upper wall surfaces 19 and 20 is
The upper wall surface 19. becomes narrower as it approaches 6.
The flow path of the mixture flowing along 20 becomes progressively narrower, and thus the speed of the mixture flow along the upper wall surface 19, 20 is gradually increased. Furthermore, as described above, the first side wall surface 14 of the partition wall 12
Since m 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.degree. A strong swirling flow is generated within the swirl portion B. 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.

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 14m of the partition wall 12 and the side wall surface 17 of the inlet passage section A, and then flows into the soil wall surface 2 of the spiral section A.
0, 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 mixed air flow that flows into the bottom wall surface 21 in the inlet passage part. This is a mixed air flow that flows into the swirl portion B along the line.

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 mixture flow is smaller than that of the first mixture flow.

Furthermore, at the exit of the branch road 24, there is a second. Since the narrowed part 16a is formed, the second mixed airflow flowing from the branch path 2J□IN, 'f' has a faster flow rate when passing through the second narrowed part 16a, and then this second mixed airflow It obliquely collides with the upper side of the first mixed air flow swirling along the side wall surface 15 of the swirl portion B, thereby deflecting the flow direction of the first mixed air flow downward. In this way, a large amount of air mixture is supplied from the branch passage 24 with low flow resistance, and the flow direction of the first air mixture flow is deflected downward, so that high filling efficiency can be obtained.

On the other hand, in the present invention, as shown in FIGS. 1 and 6, the rotary valve 25 is This prevents air-fuel mixture from leaking from the lower end of the valve body 31 when the valve is closed. However, if such a groove 36 is provided, a problem arises in that fuel accumulates in the groove 36. However, in the present invention, since the cooling water passage 38 is formed adjacent to the groove 36, vaporization of the fuel accumulated in the groove 36 can be promoted.

Further, as described above, the cooling water passage 381 has a number of holes. . 21
Number, arrow 21. As shown in the figure, cooling water flows in, but in the present invention, since the inclined side wall surface portion 21m is provided, the cooling water flow flowing in the direction of arrow Q is an intake air? - The cooling water does not flow easily into the cooling water passage 38 between the exhaust port 8 and the exhaust port 8, and thus the cooling water flow around the exhaust port 8 is improved, so that the cooling effect of the exhaust port 8 can be improved. can.

Still, the helical type intake port according to the present invention can be easily manufactured because the partition wall 12 can be integrally formed on the upper wall surface of the intake port 6.

As described above, according to the present invention, by sloping the bottom wall surface below the branch passage, most of the air-fuel mixture sent into the inlet passage during low-speed, low-load engine operation contributes to the generation of a swirling flow. A 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. Another advantage is that by sloping the bottom wall surface below the branch passage, it is possible to improve the flow of cooling water around the exhaust port.

[Brief explanation of drawings]

1 is a side sectional view of an internal combustion engine according to the present invention taken along line 1-1 in FIG. 2, FIG. 2 is a sectional plan view taken along line 1--1 in FIG. 4 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. 5 is a view taken along the line ■-■ in FIG. Figure 6 is a cross-sectional view taken along the Vt-■ 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 Figure 3, Figure 9 is a side cross-sectional view of the rotary valve, and Figure 10 is rotary valve movement control. It is a figure showing an apparatus. 4... Combustion chamber, 6... Helical intake port, 12
... Partition wall, 21 ... Bottom wall surface, 21a ... Inclined bottom wall surface portion, 24 ... Branch path, 25 ... Rotary valve. Figure 5 Figure 8 020 166 3 ISa 22b 23 Figure 6 Figure 9

Claims (1)

[Claims] In a helical intake port, the helical type intake port is configured with a spiral part formed in the intake valve barrel and an inlet passage part connected tangentially to the spiral part and extending almost straight. A branch passage communicating with the spiral terminal end of the spiral part is provided in the inlet passage, and the branch passage is connected to 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 the periphery of the intake valve stem. The entire lower space of the branch passage communicates with the inlet passage part in the cross section, and the passage walls of the inlet passage part and the branch passage are integrally connected, and an opening/closing part is provided in the branch passage. A helical intake air intake system is provided with a valve, the on-off valve controls the flow of intake air flowing through the branch passage, and the lower wall surface of the branch passage around the on-off valve is formed into an inclined surface that descends toward the inlet passage. port.