JPH0244022Y2 - - Google Patents

Description

[Detailed explanation of the idea] Industrial applications The present invention relates to an intake control device for an internal combustion engine.

BACKGROUND OF THE INVENTION A helical intake port typically consists of a spiral formed around an intake valve and an inlet passageway tangentially connected to the spiral and extending substantially straight. If such a helical intake port is used 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. A problem arises in that the filling efficiency decreases when the engine is operated at high speed and under high load with a large amount of air. 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 a rotary rotor is installed in each branch path. The valves are arranged, the valve stem of the rotary valve is made to protrude upward from the top surface of the cylinder head, an arm is attached to the protruding tip of the valve stem, and the arms of each rotary valve are connected to each other by a common connecting rod. A negative pressure diaphragm device is fixed on the outer peripheral wall of the cylinder head that protrudes upward from the outer peripheral edge of the top surface of the head, and a control rod connected to the diaphragm is connected to the control rod by protruding from the diaphragm device housing onto the top surface of the cylinder head. An intake control device in which connecting rods are connected and each rotary valve is opened by a negative pressure diaphragm device during high-load engine operation has already been disclosed in the present application, as described in Utility Application No. 163722/1983, for example. suggested by people. In an internal combustion engine equipped with this intake control device, when the engine is operated at high speed and under high load, a portion of the air-fuel mixture sent into the inlet passage of the intake port is sent into the volute of the intake port via a branch passage. The cross-sectional area of the flow path is increased, thus high filling efficiency can be obtained.

However, in this internal combustion engine, the control valve rod connected to the diaphragm passes through a cylindrical hole formed in the diaphragm device housing and protrudes above the top surface of the cylinder head, so that the lubricating oil is pumped onto the top surface of the cylinder head. A portion of the fluid flows into the diaphragm device through the gap between the control rod and the cylindrical bore. However, since the gap between the control rod and the cylindrical hole is extremely small, the lubricating oil that has flowed into the diaphragm device cannot return to the top surface of the cylinder head through the gap between the control rod and the cylindrical hole.
This creates a problem in that lubricating oil accumulates within the diaphragm device, interfering with normal operation of the diaphragm device.

OBJECT OF THE INVENTION The object of the present invention is to provide an intake air control device that can perform stable intake air control at all times by operating a diaphragm device normally at all times.

Structure of the invention The structure of the invention is such that a diaphragm device for controlling intake air flow, which has an atmospheric pressure chamber and a negative pressure chamber separated by a diaphragm, is mounted on the outer periphery of the cylinder head so that the atmospheric pressure chamber is located on the cylinder head side. A cylindrical hole that communicates the atmospheric pressure chamber with the inside of the cylinder head is formed in the diaphragm device housing that is fixed on a wall surface and defines an atmospheric pressure chamber, and a cylindrical rod connected to the diaphragm is tightly slid into the cylindrical hole. A cylindrical bellows is disposed coaxially with the rod in the atmospheric pressure chamber, and one end of the bellows is hermetically fixed to the diaphragm. The other end of the bellows is hermetically fixed to the diaphragm device housing facing the diaphragm, and a lubricating oil distribution groove extending over the entire length of the cylindrical hole is formed on the bottom wall surface of the cylindrical hole. The reason is that the internal space and the inside of the cylinder head are communicated with each other.

Embodiment Referring to FIGS. 1 and 2, 1 is a cylinder block, 2 is a piston reciprocating within the cylinder block 1, 3 is a cylinder head fixed on the cylinder block 1, and 4 is a piston 2 and a cylinder. A combustion chamber formed between the heads 3, 5 an intake valve,
6 is a helical intake port formed in the cylinder head 3, 7 is an exhaust valve, and 8 is a cylinder head 3.
Reference numeral 9 indicates an ignition plug disposed within the combustion chamber 4, and reference numeral 10 indicates a stem guide for guiding the stem 5a of the intake valve 5. As shown in FIGS. 1 and 2, the upper wall surface 1 of the intake port 6
A partition wall 12 projecting downward is integrally molded on the top of the helical intake port 6, which consists of a spiral portion B and an inlet passage portion A tangentially connected to the spiral portion B. be done. 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 gradually becomes wider as you approach. The partition wall 12 is the inlet opening 6 of the intake port 6.
The partition wall 12 further includes a first side wall surface 14a extending counterclockwise from the tip 13 to the stem guide 10 in FIG. 2, and a first side wall surface 14a extending clockwise from the tip 13 in FIG. and a second side wall surface 14b extending to the stem guide 10. 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. Next, the first side wall surface 14a 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
The side wall surface 14b extends from the tip 13 to the stem guide 10.
It extends almost immediately.

Referring to FIGS. 1 to 9, the inlet passage section A
The side wall surfaces 17, 18 of are arranged substantially vertically, while
The upper wall surface 19 of the inlet passage section A gradually descends toward the spiral section B. 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 upper wall surface 19 of the entrance passage section A is smoothly connected to the upper wall surface 20 of the spiral section B. The upper wall surface 20 of the spiral part B gradually narrows in width while descending from the connection part between the spiral part B and the inlet passage part A toward the narrowing part 16, and then gradually narrows in width.
After passing 6, the width gradually increases. On the other hand, as shown in FIG.
As shown in FIG. 8, as it approaches the spiral portion B, it rises to form an inclined surface. The angle of inclination 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 surface 14a of the partition wall 12 is a slightly downwardly inclined surface, and the second side wall surface 14b is substantially vertical. Bottom wall surface 2 of partition wall 12
2 descends from the inlet passage A toward the spiral part B while being slightly curved so that the distance from the upper wall surface 11 of the inlet passage A gradually increases as it goes from the tip 13 to the stem guide 10. Bulkhead 1
A rib 23 protruding downward from the bottom wall surface 22 is formed on the bottom wall surface 22 of No. 2 in the area indicated by hatching in FIG.
forms a slightly curved slope.

On the other hand, a branch passage 24 is provided in the cylinder head 3 that communicates the spiral end C of the spiral portion B with the inlet passage A.
is formed, and a rotary valve 25 is disposed at the inlet of this branch path 24. This branch path 24 is connected to the partition wall 12
The branch passageway 24 is separated from the inlet passageway A by , and the entire lower space of the branch passage 24 communicates with the inlet passageway 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. Bulkhead 1
The side wall surface 27 of the branch path 24 facing the second side wall surface 14b of No. 2 is substantially perpendicular, and furthermore, this side wall surface 27
is located approximately on an extension of the side wall surface 18 of the inlet passage section A. 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 valve shaft 29 rotatably supported within the rotary valve holder 28. The screw hole 30 is screwed into the screw hole 30. A thin plate-shaped valve body 31 is integrally formed at the lower end of the valve shaft 29, and as shown in FIG.
1 extends from the top wall surface 26 of the branch path 24 to the bottom wall surface 21. On the other hand, an arm 32 is attached to the upper end of the valve shaft 29.
is fixed. Further, a ring groove 33 is formed on the outer peripheral surface of the valve shaft 29, and an E-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 the valve shaft 2 is fitted by this seal member 35.
9 sealing action is performed.

Referring to FIG. 11, the arms 32 of each rotary valve 25 are connected to each other by a connecting rod 40.
The end of the connecting rod 40 is connected via a link 41 to a control rod 43 of a negative pressure diaphragm device 42. The housing 44 of the diaphragm device 42 has a projecting cylindrical portion 45 that projects outwardly about the control rod 43. On the other hand, Figures 11 and 12
As shown in the figure, a cylinder head outer peripheral wall 46 that protrudes upward is provided at the outer peripheral edge of the top surface of the cylinder head 3.
is formed, and a hole 4 is formed in the cylinder head outer peripheral wall 46.
7 is drilled. The cylindrical portion 45 of the diaphragm device 42 is fitted into the hole 47, and the cylindrical portion 45 and the hole 47
An O-ring 48 is inserted between them. A diaphragm 49 is disposed within the diaphragm device housing 44, and the diaphragm 49 separates the interior of the housing 44 into a negative pressure chamber 50 and an atmospheric pressure chamber 51. A compression spring 52 for pressing the diaphragm is inserted into the negative pressure chamber 50, and the negative pressure chamber 50 is further connected to an intake manifold branch pipe 55 via a throttle 53 and a negative pressure conduit 54. On the other hand, inside the atmospheric pressure chamber 51, a cylindrical bellows 56 made of a rubber material is arranged. One end of the bellows 56 is hermetically secured to the diaphragm 49, and the other end of the bellows 56 is hermetically secured to the inner wall surface of the housing 44. Inside the bellows 56, the stop spring 5
7 is fixed to the control rod 43, and the axial movement of the control rod 43 is restricted by this stop ring 57. As shown in FIGS. 11 to 13, an inner cylindrical hole 58 is formed in the cylindrical portion 45 of the housing 44. As shown in FIGS. A cylindrical control rod 43 is slidably inserted into the inner cylindrical hole 58, and the control rod 43 passes through the inner cylindrical hole 58. Furthermore, the inner cylindrical hole 58 is provided at the upper and lower parts of the inner wall surface of the inner cylindrical hole 58.
Lubricating oil distribution grooves 59, 60 extending over the entire length of the bellows 56 are formed, and the inside of the bellows 56 is formed with these grooves 59, 60.
It communicates with the top surface of the cylinder head 3 via 60. During low engine load operation, a large negative pressure is applied to the negative pressure chamber 50, so the diaphragm 49 moves toward the negative pressure chamber 50 against the compression spring 52. As a result, the rotary valve 25 is rotated counterclockwise and the rotary valve 25 closes the branch passage 24. on the other hand,
When the engine is operated under high load, the negative pressure in the negative pressure chamber 50 becomes small, so the diaphragm 49 moves toward the atmospheric pressure chamber 51 by the spring force of the compression spring 52. As a result, the rotary valve 25 is rotated clockwise and the rotary valve 25 fully opens the branch passage 24. As mentioned above, when the engine load decreases, the diaphragm 49 moves toward the negative pressure chamber 50, so that part of the lubricating oil sent to the top surface of the cylinder head 3 is transferred to the pair formed in the cylindrical portion 45 of the housing 44. It flows into the bellows 56 through the grooves 59 and 60. However, when the engine load increases and the diaphragm 49 moves toward the atmospheric pressure chamber 51, this lubricating oil is returned to the top surface of the cylinder head 3 via the grooves 59 and 60. That is, a pair of grooves 59,
By forming the groove 60, the flow area of the lubricating oil is increased, and by forming one of the grooves 60 on the lower side of the control rod 43, the lubricating oil accumulated below the bellows 56 can be easily discharged. Therefore, the lubricating oil accumulated in the bellows 56 can be efficiently discharged.

As mentioned above, the rotary valve 25 closes the branch passage 24 when the engine is operating at low load with a small amount of intake air. At this time, part of the air-fuel mixture sent into the inlet passage A advances along the upper wall surfaces 19 and 20, and part of the remaining air-fuel mixture collides with the rotary valve 25 and flows into the inlet passage. After changing its direction toward the side wall surface 17 of section A, it proceeds along the side wall surface 15 of spiral section B. As described above, the widths of the upper wall surfaces 19 and 20 gradually become narrower as they approach the narrowed portion 16, so that the flow path for the air-fuel mixture flowing along the upper wall surfaces 19 and 20 gradually narrows. The air mixture flow along 20 is gradually accelerated. Further, as described above, the first side wall surface 14a of the partition wall 12 has a spiral portion B.
Since it extends to the vicinity of the side wall surface 15, the upper wall surface 1
The air mixture flowing along the spiral portions 9 and 20 is forced onto the side wall surface 15 of the spiral portion B, and then proceeds along the side wall surface 15, so that a strong swirling flow is generated within the spiral 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 opens, so the inlet passage A
The air-fuel mixture sent into the tank is divided into three main streams. That is, the first flow is a mixed gas flow that 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 while swirling along the upper wall surface 20 of the spiral section B. 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 a mixed air flow that flows into the spiral part B along .
The flow resistance of the branch path 24 is smaller than the flow resistance between the first side wall surface 14a and the side wall surface 17, and therefore
The number of mixed air flows is larger than that of the first mixed air flow. Further, 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 air mixture flow from the branch passage 24 with low flow resistance increases, and furthermore the first
Since the flow direction of the air mixture flow is deflected downward, high filling efficiency can be obtained. Further, as mentioned above, since the bottom wall surface of the partition wall 12 is formed as a downwardly inclined surface, the third air mixture flow is guided by this inclined surface and the flow direction is deflected downward, thus achieving even higher filling efficiency. will be obtained.

Effects of the Invention By arranging the bellows within the atmospheric pressure chamber of the negative pressure diaphragm device, lubricating oil flowing from the cylinder head to the negative pressure diaphragm device via the lubricating oil flow groove is captured within the bellows. the result,
Since it is possible to prevent a large amount of lubricating oil from accumulating in the atmospheric pressure chamber of the negative pressure diaphragm device, it is possible to prevent the accumulated lubricating oil from affecting the operation of the diaphragm. Furthermore, since no pressure difference occurs between the inside and outside of the bellows, no large stress is applied to the bellows, thus ensuring good durability of the bellows. Furthermore, since the cylindrical control rod is slidably inserted into the cylindrical bore, the control rod is not tilted relative to the cylindrical bore. As a result, the stroke of the control rod can be accurately maintained at a predetermined stroke at all times, so that the intake air flow can be controlled with high precision.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the internal combustion engine according to the present invention taken along the - line in Fig. 2, Fig. 2 is a plan sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view according to the present invention taken along the - line in Fig. 2. FIG. 4 is a side view schematically showing the shape of the helical intake port, 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 FIGS. 3 and 4. 6 is a sectional view taken along the - line 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 in FIGS. 3 and 4, FIG. 9 is a sectional view taken along the line - in FIGS. 3 and 4, and FIG.
Figure 0 is a side sectional view of the rotary valve, Figure 11 is a plan view of the internal combustion engine, Figure 12 is a sectional view taken along line XII-XII in Figure 11, and Figure 13 is a perspective view of the negative pressure diaphragm device. It is. 4... Combustion chamber, 6... Helical intake port,
12... Partition wall, 24... Branch path, 25... Rotary valve, 42... Negative pressure diaphragm device, 43...
Control rod, 44...Housing, 58...Inner cylinder hole, 59, 60...Groove.

Claims (1)

[Scope of utility model registration request] A diaphragm device for controlling intake air flow having an atmospheric pressure chamber and a negative pressure chamber separated by a diaphragm is fixed on the outer circumferential wall surface of the cylinder head with the atmospheric pressure chamber located on the cylinder head side. A cylindrical hole communicating between the atmospheric pressure chamber and the inside of the cylinder head is formed in a diaphragm device housing that defines a pressure chamber, and a cylindrical rod connected to the diaphragm is inserted into the cylindrical hole so as to be tightly slidable therein. A cylindrical bellows is provided extending through the cylindrical hole to the inside of the cylinder head, disposed coaxially with the rod in the atmospheric pressure chamber, and sealingly fixes one end of the bellows to the diaphragm. The other end of the bellows is hermetically fixed to the diaphragm device housing facing the diaphragm, and a lubricating oil distribution groove is formed on the bottom wall surface of the cylindrical hole extending the entire length of the cylindrical hole, and the lubricating oil distribution groove An intake air control device for an internal combustion engine that communicates the interior space of a bellows with the interior of a cylinder head.