JPH0133790Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a flow path control device for a helical intake port used in 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 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 engine 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 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 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, 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, this helical intake port is suitable for internal combustion engines that use a carburetor as a fuel supply source, and in internal combustion engines that inject fuel into the intake port, even if the above-mentioned helical intake port is applied as is, there will be no injection. The challenge is to supply fuel into the engine cylinders with good response.

Purpose of the invention The object of the invention is to provide a helical intake port suitable for an internal combustion engine that injects fuel into the intake port.

Structure of the invention The structure of the invention is that in a helical intake port configured by a spiral part formed around the intake valve and an inlet passage part connected tangentially to the spiral part and extending almost straight, the inlet passage A branch passage branching from the part and communicating with the spiral terminal part of the spiral part is provided in the inlet passage part, and the branch passage is formed 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. A communication opening that is separated from the inlet passage and communicates the branch passage with the inlet passage is formed in a longitudinally intermediate portion of the partition, so that the communication opening allows the partition to be located downstream of the first partition part located on the upstream side. Separated into two large bulkhead portions, a fuel injection valve is disposed within the communication opening, and an on-off valve is provided within the branch path defined by the first bulkhead portion, so that the on-off valve is closed during low engine load operation. It's because I did it.

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
1 is integrally formed with a partition wall 12 projecting downward, and this partition wall 12 forms a helical intake port 6 consisting of a spiral portion B and an inlet passage portion A tangentially connected to the spiral portion B. be done. A communication opening 13 is formed in the longitudinally intermediate portion of the partition wall 12, and in the embodiment shown in FIGS. 1 partition wall portion 12a and a second partition wall portion 1 located downstream of the communication opening 13.
It is divided into 2b. The first
The partition portion 12a has a substantially uniform width and has a first side wall surface 14a and a second side wall surface 14b on both sides thereof. On the other hand, the second partition wall portion 12b extends from the communication opening 13 beyond the stem guide 10 to the side wall surface 1 of the spiral portion B.
5, and further extends to the vicinity of this second partition wall portion 12b.
is the stem guide 1 counterclockwise from the communication opening 13.
The first side wall surface 14a extending to 0 and the communication opening 13
The second stem guide 10 extends clockwise from
It has a side wall surface 14b. The first side wall surface 14a of the second partition wall portion 12b extends from the communication opening 13 through the side of the stem guide 10 to the vicinity of the side wall surface 15 of the spiral portion B, and has a narrowed portion 1 between it and the spiral portion side wall surface 15.
form 6. 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 side wall surface 14b extends from the communication opening 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 towards 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
The width gradually narrows while descending from the connecting part of the inlet passage part A toward the narrowed part 16, and then, after passing through the narrowed part 16, the width gradually widens. On the other hand, the lower wall surface 21 of the inlet passage section 6 is substantially horizontal and extends to the spiral section B.

On the other hand, the bottom wall surface 22 of the first partition wall portion 12a extends substantially parallel to the top wall surface 19, while the second partition wall portion 12a extends substantially parallel to the top wall surface 19.
The bottom wall surface 22 of a gradually descends from the communication opening 13 toward the spiral portion B. A fuel injection valve 23 is disposed at the top of the communication opening 13, and fuel is injected from the fuel injection valve 23 toward the back surface of the bulk part of the intake valve 5.

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 2 is installed at the inlet of the branch passage 24.
5 is placed. This branch 24 is separated from the inlet passage A by a first partition part 12a and a second partition part 12b. Upper wall surface 26 of branch road 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 portion B. 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;
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 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 this sealing member 35 connects the valve shaft 2.
9 sealing action is performed.

Referring to FIG. 11, the tip of the arm 32 fixed to the upper end of the rotary valve 25 is connected via a connecting rod 43 to a control rod 42 fixed to a diaphragm 41 of a negative pressure diaphragm device 40. As shown in FIG. The negative pressure diaphragm device 40 has a negative pressure chamber 44 isolated from the atmosphere by a diaphragm 41, into which a compression spring 45 for pressing the diaphragm is pushed. On the other hand, the intake port 6 is connected to a surge tank 47 via a branch pipe 46, and a throttle valve 4 connected to an accelerator pedal (not shown) is provided in an air introduction pipe 48 of the surge tank 47.
9 is inserted.

As shown in FIG. 11, the negative pressure chamber 44 of the negative pressure diaphragm device 40 is connected to a surge tank 47 via a negative pressure conduit 50. Therefore, during engine bottom load operation with a small opening degree of the throttle valve 49, a large negative pressure is applied in the negative pressure chamber 44, so the diaphragm 41 moves toward the negative pressure chamber 44 against the compression spring 45, and at this time, the rotary The valve 25 is rotated and the rotary valve 25 is fully closed. On the other hand, when the engine is operated under high load with a large opening of the throttle valve 49, the negative pressure applied to the negative pressure chamber 44 decreases, so the diaphragm 41 moves toward the rotary valve 25, thereby causing the rotary valve 25 to fully open. It will be done.

As described above, the rotary valve 25 is closed during engine bottom load operation. At this time, most of the intake air sent into the inlet passage section A is on the upper wall surface 19,
20, a part of the air-fuel mixture flows into the branch passage 24 through the communication opening 13, as indicated by the arrow K in FIG. From the fuel injection valve 23, the second
Fuel is injected toward the upstream end of the partition wall portion 12b, and this fuel is divided into two parts by the upstream end of the second partition wall portion 12b, and is divided into two parts, respectively, into an inlet passage section A and a branch passage 24.
supplied within. As mentioned above, the upper wall surfaces 19, 2
Since the width of 0 gradually becomes narrower as it approaches the narrowed portion 16, the flow path of the air-fuel mixture flowing along the upper wall surfaces 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 second partition wall portion 12b extends to the vicinity of the side wall surface 15 of the spiral portion B, so that the air mixture flowing along the upper wall surfaces 19 and 20 flows 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. At this time, since the amount of intake air that flows into the branch passage 24 through the communication opening 13 is small, the swirling flow is hardly weakened by this intake air, and thus, as described above, the flow inside the combustion chamber 4 is reduced. can generate a strong swirling flow.

On the other hand, during high-load engine operation, the rotary valve 25 opens, so that the air-fuel mixture sent into the inlet passage A is roughly divided into three streams. That is,
The first flow is a mixed 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 A. The flow is a mixed air flow that flows into the swirl portion B via the branch passage 24, and the third flow is a mixed air flow that flows into the swirl portion B along the bottom wall surface 21 of the inlet passage portion A. The flow resistance of the branch passage 24 is smaller than the flow resistance between the first side wall surface 14a and the side wall surface 17, and therefore the second air mixture flow is smaller than the flow resistance between the first side wall surface 14a and the side wall surface 17.
will be more than the mixed air flow. Furthermore, the flow direction of the first air mixture flowing while swirling inside the swirl part B is the second
It is deflected downward by the air mixture flow, thus weakening the swirling force of the first air mixture flow. 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.

Effect of the invention In the embodiment shown in FIGS. 1 and 2, the first
When the fuel injection valve 23 is disposed upstream of the partition wall portion 12a, a part of the fuel injected from the fuel injection valve 23 adheres to the rotary valve 25 when the rotary valve 25 is closed, and thus the combustion chamber This causes a problem in that the transient response of the engine is deteriorated because the supply of fuel to the engine is delayed. However, in the present invention, since the fuel injection valve 23 is provided downstream of the rotary valve 25, there is no risk of fuel adhering to the rotary valve 23.
Since the intake port 6 is located in the center of the intake port 6, the amount of fuel adhering to both side wall surfaces 17 and 27 of the intake port 6 is small, thus ensuring good transient response.

[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.
FIG. 0 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,
12a...first partition part, 12b...second partition part, 24...branch path, 25...rotary valve.

Claims (1)

[Scope of utility model registration request] In a helical intake port configured with a spiral part formed around the intake valve 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 and the spiral part is connected to the spiral part in a tangential manner and extends almost straight. A branch passage communicating with the spiral terminal end of the part is provided in the inlet passage part, and the branch passage is separated from the inlet passage part by a partition wall that projects downward from the upper wall surface of the intake port and extends from the inlet passage part to around the intake valve stem. A communication opening is formed in a longitudinally intermediate portion of the partition wall to communicate the branch passage and the inlet passage, and the communication opening allows the partition wall to separate into a first partition wall portion located on the upstream side and a first partition wall portion located on the downstream side. Separated into two partition wall parts, a fuel injection valve is arranged in the communication opening, an on-off valve is provided in a branch path defined by the first partition part, and the on-off valve is closed during low engine load operation. A flow path control device for a helical intake port.