JPS58200027A - Flow duct controller of helical suction port - Google Patents

Abstract

PURPOSE:To enable to control an opening and closing valve in accordance with a suction air quantity without applying an electronic control unit, by holding the opening and closing valve at a fully-closed, a half-opened and a fully-opened positions according to the suction air quantity by leading negative pressure into a pair of negative pressure chambers selectively. CONSTITUTION:When an opening of a primary side throttle valve 55 is small, negative pressure to be generated at a venturi part 53 is small and large negative pressure is generated within a suction manifold 37. Then, when the opening of the primary side throttle valve 55 becomes large, a stopper 50 is pushed by a diaphragm 44 and a rotary valve 25 is turned into a half-opened state, as negative pressure to be applied to a negative pressure chamber (d) becomes larger than about 8mm.Hg and the inside of a second negative chamber 47 becomes the atmospheric pressure. Then, when the opening of the primary side throttle valve 55 becomes larger than about 20mm.Hg, that is, at the time of a high speed and a high load, the inside of a first negative pressure chamber 46 becomes atmospheric pressure, too, and the rotary valve is fully opened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow path control device for a helical intake port.

The helical intake valve M is usually composed of a spiral portion formed in the intake valve M, 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 when the engine is operating at low speed and low load with a small amount of intake air, the shape of the intake port will have a large flow resistance. A problem arises in that the filling efficiency decreases during high-speed, high-load operation of the engine with many air caps. To solve this problem, a branch path is formed in the cylinder head that branches off from the helical intake/-) inlet passage and communicates with the spiral end of the helical intake port spiral section, and an opening/closing mechanism is formed within the branch path. The applicant has already proposed a helical intake port which is provided with a valve and is opened in response to an increase in the amount of intake air. In this helical type intake port, when the amount of intake air is large, a part of the intake air that is sent into the helical type intake port inlet passage □ is sent into the helical type intake port spiral part through the branch path. The cross-sectional area of the intake air flow path is increased, and thus the filling efficiency can be improved. However, in this helical intake I-T, 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. Since the cross-sectional area of the inlet passage is limited, it is 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. A helical intake port with a groove is formed in the cylinder head. Furthermore, this helical intake port requires an electronic control unit to open the on-off valve in response to an increase in the amount of intake air, so the on-off valve control device is complicated, and as a result, the manufacturing of the control device is complicated. There are problems in that the cost increases and the reliability of the control device decreases.

The present invention provides a helical intake port that can obtain high charging efficiency when the engine is operated at high speeds and can open and close the valve according to the increase in intake air amount without using an electronic control unit. An object of the present invention is to provide a flow path control device.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, 1 is a cylinder block, 2 is a piston that reciprocates within the cylinder block 1,
3 is a cylinder spatula Y 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 in the cylinder head 3, 7 is an exhaust valve, 8 is formed in the cylinder head 3 9 indicates an ignition plug disposed within the combustion chamber 4, and 10 indicates a stem guide for guiding the stem 5a of the intake valve 5. As shown in FIGS. 1 and 2, a partition wall 12 projecting downward is integrally formed on the earthen wall surface 11 of the VC intake port 6, and this partition wall 12 forms a spiral portion B and a line tangential to the spiral portion B. A helical intake port 6 consisting of an artificial passageway portion A connected to is formed. This partition ki12 extends from the inlet passage part A (c) to around the stem guide lO of the intake valve 5, and as can be seen from FIG. It gradually becomes wider as it approaches the stem guide 10. 412&:t at the interval, intake port 6 entry 1] opening 6a
has a tip 13 located on the side closest to tci4
The wall 12 is a first side extending counterclockwise from this tip 13 to the stem guide 10 in FIG. It has an IJ 14a and a second side wall 14b extending from the tip figs 13 to the stem guide 10 in the n and y stitches.

The stem guide 10 from the first side wall surface 14a & the tip end 13
It extends to the vicinity of the @ wall surface 15 of the spiral portion B through the side thereof, and forms a narrow portion 16 between the spiral portion side wall surface 15 and the spiral portion B. Next, the first side wall surface 14m extends to the stem guide 10 while being curved so as to be gradually spaced apart from the spiral portion side wall surface 15. On the other hand, the second side wall surface 14b extends substantially straight from the distal end portion 13 to the stem guide 10.

Referring to FIGS. 1 to 9, the side walls 17, 18 of the inlet passage A are arranged vertically, while the upper wall 19 of the inlet passage A gradually descends toward the spiral part B. The side wall surface 17 of the artificial passage section is smoothly connected to the side wall surface 15 of the spiral section B, and the upper wall surface 19 of the entrance passage section is smoothly connected to the upper wall surface 20 of the spiral section B. The wall surface 20 gradually narrows in width as it descends from the connection between the spiral portion B and the inlet passageway toward the narrowed portion 16, and then gradually widens as it passes through the narrowed portion 16. On the other hand, the lower wall surface 2 of the inlet passage section 6
As shown in FIG. 5, the entire #de is horizontal in the vicinity of the entrance opening nozzle, and the bottom wall surface portion 21m adjacent to the side wall surface 17 has a spiral portion as shown in FIG. As it approaches B, it rises and forms an inclined surface. The #1fi4 angle of this inclined bottom wall surface portion 21a gradually increases as it approaches the spiral portion B.

On the other hand, the first side wall 14a of the partition wall 12 has a slightly downwardly inclined surface, and the second wall surface 14b is substantially vertical. The bottom wall surface 22 of the partition wall 12 is slightly curved from the inlet passage section A toward the spiral section B so that the distance from the earth wall surface 11 of the inlet passage section 6 gradually increases from the tip end 13 toward the stem guide 10. Go down.

On the bottom wall surface 22 of the partition wall 12, a rib 23 is formed which projects downward from the bottom wall surface 22 in the area shown by the notch in FIG. form a surface.

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 branch passage i4 with the inlet passage A, and a rotary valve 25 is disposed at the entrance of the branch passage i4.

This branch passage 24 is separated from the entrance passage section A by the partition wall 12, and the entire lower space of the branch passage 24 communicates with the artificial passage section A. The upper wall surface 26 of the branch passage 24 has a substantially uniform width, gradually descends toward the spiral terminal end C, and is smoothly connected to the upper wall surface 20 of the spiral section B. A side wall surface 27 of the branching passage 24 facing the second side wall surface 14bK of the partition wall 12 is substantially vertical, and furthermore, this side wall surface 27 is substantially parallel to the inlet passage section A.
It is located on an extension of the side wall surface 18 of. As can be seen from FIG. 1, the rib 23 formed on the partition wall 12 extends from the vicinity of the rotary valve 25 toward the intake valve 5.

As shown in FIG. 10, the rotary valve 25 is composed of a rotary valve holder 28 and a nine-valve shaft 29 rotatably supported within the rotary valve holder 28. It is screwed into a screw hole 30 drilled in the 21t cylinder head 3.

A thin plate-shaped valve body 31 is integrally formed at the lower end of the valve shaft 29, and as shown in FIG. 29
An arm 32 is fixed to the upper end of the holder. Further, a puffer groove 33 is formed on the outer peripheral surface of the valve stem 4,
An E-shaped positioning ring 34 is fitted into this ring groove 33. Furthermore, 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 FIG. 11, an intake manifold 37 is attached to the cylinder head 3, and the intake manifold 37 is equipped with a conno-round type carburetor a36 consisting of a primary carburetor 36& and a secondary carburetor 36b. The distal end of the arm 32 fixed to is connected to a control rod 41 of a negative pressure diaphragm device 40 via a connecting rod 42. This negative pressure diaphragm device 40 includes a pair of diaphragms 43 and 44tl arranged in tandem, and these diaphragms 43 and 44 cause a negative pressure diaphragm device 1140 to
The inside of is an atmospheric pressure chamber 45, a first negative pressure chamber 46, and a second negative pressure chamber 4.
It is divided into 7 and 3 parts. - A compression spring 48 that presses the diaphragm 43 is inserted into the first negative pressure chamber 46, and a compression spring 49 that presses the diaphragm 44 is inserted into the second negative pressure chamber 47.
is inserted. History C: A stopper 50 that can come into contact with the diaphragm 44 is fixed to the diaphragm 43. 1st
As shown in FIG. 1, the first negative pressure chamber 46 is connected to the first switching valve 51, and the second negative pressure chamber 47 is connected to the second switching valve 52. These switching valves 51, 52 have a similar construction, and therefore similar components are designated with the same reference numerals. switching f
f51 and 52 have passages a connected to the first negative pressure chamber 46 and the second negative pressure chamber 47, respectively, and these passages aFi are connected into the intake manifold 37 via check valves aFi. The switching valves 51 and 52 each have a negative pressure chamber d and an atmospheric pressure chamber 6 separated by a diaphragm C, and the negative pressure chamber dFi
Venturi portion 53 of the primary side carburetor 36a. The port 54 is connected to the port 54 which is open to the port 54. On the other hand, the diaphragm cK is a valve,
+? -) The atmospheric pressure chamber e, in which the valve body g for controlling the opening and closing of f is fixed, is connected on the one hand to the corresponding negative pressure chamber 46, 47 via the valve port f and the passage a, and on the other hand, the air filter h is A compression spring i that presses the diaphragms J and C is inserted into a negative pressure chamber d that communicates with the atmosphere through the diaphragm, and the compression spring i of the first switching valve 51 is also similar to the compression spring i of the second switching valve 52. Has a large spring force. Therefore, when the negative pressure in the negative pressure chamber d increases, first the valve body g of the second switching valve 52 opens the valve port f, and then the valve body g of the first switching valve 51 opens the valve boat f. .

The carburetor 36 is a commonly used carburetor, and when the primary throttle valve 55 is opened for a predetermined period of time or more, the secondary throttle valve 56 opens, and when the primary throttle valve 55 is fully opened. If so, the secondary throttle valve 56 is also fully opened. The negative pressure generated in the venturi part 53 of the primary side carburetor 36m increases as the amount of intake air supplied into the engine cylinder increases. Therefore, when the opening degree of the primary side throttle valve 55 is small, the negative pressure generated in the venturi part 53 Since the generated negative pressure is small, the diaphragm C of the switching valve 51, 52 moves into the atmospheric pressure chamber allVC by the spring force of the compression spring t, and the valve body g closes the valve port f. Furthermore, in this way, the primary side throttle valve 5
5 is small, a large negative pressure is generated in the intake manifold 37P3. The check valve allows the negative pressure in the intake manifold 37 to be transferred to the negative pressure chamber 46 of the negative pressure diaphragm device 40.
, 47 becomes smaller than the negative pressure in the noble house 4647, the valve closes, so as long as the valve body g closes the valve port f, the negative pressure in the negative pressure chambers 46 and 47 is the intake air. The maximum negative pressure developed within the manifold 37 is maintained. Negative pressure chamber 46,
When negative pressure is applied to 47P3, both diaphragms 43.4a move to the second negative pressure chamber 4711 against the compression springs 4B and 49, and at this time they come into contact with the diaphragm 44. In this way, both dia slams 43, 44
moves toward the Wi2 negative pressure chamber 47, the rotary valve 25 completely closes the branch passage 24.

Next, when the opening degree of the primary 4 throttle valve 55 increases and the negative pressure applied to the negative pressure chamber d of the switching valves 51 and 52 becomes larger than the first set negative pressure 1, for example -811Hf, the first switching cell The valve body g of 52 opens the valve port f. As a result, the inside of the second shell pressure chamber 47 becomes atmospheric pressure, so that the diaphragm 44
is moved toward the first negative crown 46' by the spring force of the compression spring 49 while in contact with the stopper 50. As a result, the damping rod 41 protrudes, causing the rotary valve 25 to rotate, and at this time, the rotary valve 25 is held in the half-open position shown in phantom in Figure 452.

Next, the opening of the primary throttle valve 55 becomes even larger, and the negative pressure applied to the negative pressure chamber d of the switching valves 51, 520 becomes larger than the first set negative pressure, for example, vr-zomHt, that is, the engine cylinder speed increases. Valve body g4 of the second switching valve 51 during multi-load operation
The 5F port f is opened, and the inside of the @1 negative pressure 46 also becomes atmospheric pressure. Therefore, at this time, the diaphragm 43iJ[1
As shown in Figure 1, atmospheric pressure chamber 45 $1. ．． The rotary valve 25 fully opens the branch passage 24.

As mentioned above, during engine speed and low load operation where the intake air is small, the rotary valve 25 and the MM 24 are closed. At this time, a part of the air-fuel mixture sent into the artificial passageway TBA flows onto the upper wall surface 19.20, and a part of the remaining air-fuel mixture collides with the rotary valve 25 and enters the inlet. Passage F
M5AoII After turning towards wall 17, spiral 8B
Proceed along one wall 15 of . As mentioned above, the upper wall surface 19
．． Since the width of 20 gradually narrows as it approaches the constriction 816, the flow path for the mixture flowing along the upper wall surface 19.20 becomes gradually narrower, and thus the flow of the mixture gas along the upper wall surface 19.20 gradually increases. be speeded up. Furthermore, as described above, the first@wall surface 14m of the partition wall 12 extends to the vicinity of the side wall surface 15 of the spiral portion B, so the air mixture flowing along the soil wall surface 19.20 flows onto the side wall surface 15 of the spiral portion B. A strong swirling flow is generated in the spiral portion B because the fluid is pushed away and then proceeds along the side wall surface 15. 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 opening degree of the primary throttle valve 55 increases and the intake air flow increases, the rotary valve 25 is opened and held in the half-open state as described above. At this time, part of the air-fuel mixture supplied into the inlet passage section A is transferred to the branch passage 24t-
Since the swirling air is fed into the spiral portion B through the air, the swirling flow is slightly separated, and the resistance to the intake airflow is reduced, so that the filling efficiency is improved. When the amount of intake air is small, it is necessary to generate strong turbulence within the combustion chamber 4 in order to ensure stable combustion, but as the amount of intake air increases, the naturally occurring turbulence becomes stronger, and the swirling flow is more likely to occur. It is necessary to suppress forced disturbances such as
Furthermore, as the amount of intake air increases, it is necessary to prevent the charging efficiency from decreasing, which causes a decrease in output. Therefore, as the amount of intake air increases, by increasing the opening area of the rotary valve 25, the generation of swirling flow is suppressed and a decrease in filling efficiency is prevented. Filling efficiency can be ensured.

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 fully opened, so the air-fuel mixture sent into the inlet passage A can be roughly divided into three flows: This is a mixed air flow that flows between the first side wall surface 14a of the partition wall 2'' and the side wall surface 17 of the inlet passage sA, and then flows while swirling along the upper wall surface 20 of the spiral part A, and the second flow flows into the branch passage. is a mixed air flow flowing into the swirl part B via 24,
The third flow is a mixed air flow that flows into the swirl section B along the bottom wall surface 21 of the inlet passage section A.

The flow resistance of the branch path 24 is the first side wall surface 14a,! =II is smaller than the flow resistance between the wall surfaces 17, so the second mixed air flow is larger than the first mixed air flow.

Furthermore, the flow direction of the first air mixture flowing while swirling in the swirl portion B is deflected downward by the second air mixture, thus weakening the swirling force of the first air mixture. In this way, the mixed air flow from the branch passage 24 with low flow resistance is increased, and the flow direction of the first mixed air flow is further deflected downward, so that high filling efficiency can be obtained.

Further, in the helical type (@l'-) according to the present invention, the partition wall 12 can be integrally formed on the earthen 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, the engine speed is low and the engine is placed low.) During load operation, the branch path T- is shut off and a large amount of air-fuel mixture flows along the upper wall surface of the vortex part, thereby creating a strong swirling flow inside the combustion chamber. can be caused to occur. Furthermore, as the amount of intake air increases, the swirling flow can be suppressed and the charging efficiency can be increased, so stable combustion can be ensured.

Further, since only the partition wall protrudes into the intake air (/-), the flow resistance to the intake air flow is small, and thus high filling efficiency can be obtained during engine high-speed, high-load operation. Furthermore, since the rotary valve opening/closing control can be performed mechanically, the manufacturing cost of the rotary valve opening/closing control device can be reduced, and the reliability of the Roguts valve opening/closing control device can be improved.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an internal combustion engine according to the present invention taken along line I-1 in FIG. 2, FIG. 2 is a plan sectional view taken along line T in FIG. 1, and FIG. 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; FIG. 5 is the V of FIGS. - Cross-sectional view along line V, No. 6
The figure is a sectional view taken along the line W-11 in Figs. 3 and 4, Fig. 7 is a sectional view taken along the line ■-■ in Figs. 3 and 4, and Fig. 8 is a sectional view taken along the line Figure 9 is a sectional view taken along the line ■-■- in Figures 3 and 4, and Figure 9 is a cross-sectional view taken along the line -
10 is a side sectional view of the rotary valve, and FIG. 11 is a diagram showing a drive control device for the rotary valve. 4... Combustion chamber, 6... Helical intake port, 12
...Partition wall, 24... Branch passage, 25... Rotary valve, 4°... Negative pressure diaphragm device, 51.52...
switching valve. Patent Applicant Toyota Motor Corporation Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Patent Attorney Akira Yamaguchi Figure 1! lsZ diagram Figure 7 Figure 9 Figure $8 Figure 10

Claims (1)

[Claims] In a helical intake port configured by a spiral portion formed in the intake valve leg and an inlet passage portion that is tangentially connected to the spiral portion and extends almost straight, the intake port is branched from the inlet passage portion. A branch passage communicating with the spiral end of the spiral part is provided in the inlet passage part, and a sand branch passage is connected to 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 around 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. The opening/closing valve is connected to a negative pressure diaphragm device provided with a valve and a pair of negative pressure chambers, and the pair of negative pressure chambers are connected to a negative pressure source as a switching valve responsive to the amount of intake air. By selectively introducing negative pressure into the pair of negative pressure chambers through the switching operation of the switching valve, the on-off valve is set to one of the fully closed, half-open, and fully open positions depending on the amount of intake air. A flow path control device for a helical intake port that maintains