JPS6021470Y2 - Helical intake port - Google Patents

Description

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

A helical intake port usually includes a spiral portion formed at the intake position and an inlet passage portion tangentially connected to the spiral portion 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 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. There is 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 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 an actuator is actuated within the branch path. The present applicant has developed a helical intake port flow path control device that is equipped with a normally closed on-off valve and operates an actuator to open the on-off valve when the amount of engine intake air becomes larger than a predetermined amount. Already proposed.

In this helical type intake port, when the engine is operated at high speed and under high load with a large amount of engine intake air, 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 the branch passage. The flow resistance to the intake air flow is reduced and thus a high filling efficiency can be obtained.

However, such a helical intake port itself has a complicated shape, and if a branch passage is added, the shape becomes extremely complicated. It is quite difficult to form.

The object of the present invention is to provide a helical intake port with a novel 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 in the cylinder head 3, 7 8 indicates an exhaust valve, and 8 indicates an exhaust port formed in the cylinder head 3.

Although not shown in the figure, an ignition plug is disposed within the combustion chamber 4.

As shown in FIG. 1, a truncated conical projection 10 that protrudes downward to hold the valve stem guide 9 is integrally formed on the upper wall surface of the helical intake port 6, and the tip of the truncated conical projection 10 The distal end portion of the valve stem guide 9 protrudes from the portion.

As shown in FIG. 2, the helical intake port 6 is composed of an inlet passage section A that extends substantially straight and a spiral section B, and the inlet passage section A is connected to the spiral section B in a tangential manner.

As shown in FIGS. 1 to 8, the side wall surface 11 of the inlet passage A away from the spiral axis a is arranged substantially vertically, and this side wall surface 11 forms a spiral section that curves around the spiral axis a. It connects smoothly to the side wall surface 12 of B.

On the other hand, the side wall surface 13 of the inlet passage section A closer to the spiral axis a
As shown in FIGS. 5 and 6, this is formed on a downwardly inclined wall surface in the downstream region near the spiral portion B.

The upper part of this inclined side wall surface 13 is smoothly connected to the conical peripheral wall surface of the cylindrical projection 11 shown in FIG. is connected to the side wall surface 12 of.

As shown in FIG. 8, the width of the earthen wall surface 14 of the entrance passage section A gradually narrows toward the spiral section B, and then smoothly connects to the upper wall surface 15 of the spiral section B.

The bottom wall surface 16 of the inlet passage section A extends substantially parallel to the top wall surface 14 toward the spiral section B, and then forms a smooth curved wall surface 17.
It is connected to the cylindrical outlet part 18 of the volute part B through.

On the other hand, as shown in FIGS. 2 to 8, there is a branch passage 19 in the cylinder head 3 that communicates the substantially longitudinal center of the inlet passage A with the spiral end C of the spiral part B. A rotary valve 20 constituting an on-off valve is inserted into this branch path 19.

This branch 19 is separated from the inlet passage A by a partition wall 21 which projects downward from the upper wall surface 14 of the inlet passage A and extends in the flow direction of the intake air flow.

The lower end of this partition wall 21 is arranged at a slight distance upwardly from the common bottom wall 14 of the inlet passage section A and the branch passage 19, so that the space below the branch passage 19 in the longitudinal direction extends over its entire length. It communicates with the inlet passage A in the cross section.

One side wall surface 22 of the branching path 19, that is, the side wall surface 22 of the partition wall 21 located on the opposite side to the inclined wall surface 13, is arranged approximately perpendicularly, and the other side wall surface 23 of the branching path 19 is approximately parallel to the side wall surface 22. vertically arranged.

Further, the upper wall surface 24 of the branch passage 19 is arranged in substantially the same plane as the upper wall surface 14 of the inlet passage section A.

As shown in FIG. 9, the rotary valve 20 is composed of a rotary valve holder 26 and a valve shaft 27 rotatably supported within the rotary valve holder 26. The opening/closing valve insertion hole 28 is screwed into the opening/closing valve insertion hole 28.

A thin plate-shaped valve body 29 is formed at the lower end of the valve shaft 27 .

As shown in FIGS. 3, 5, and 6, the lower end of the valve body 29 is spaced apart from the bottom wall 16, and the intake air is provided between the lower end of the valve body 29 and the bottom wall 16. Distribution space 25
is formed.

On the other hand, an arm 30 is attached to a washer 31 at the upper end of the valve shaft 27.
It is secured by a bolt 32 through the .

Further, a ring groove 33 is formed on the outer peripheral surface of the valve shaft 27, and an E-shaped positioning ring 34, for example, for positioning the valve body 29 is fitted into the ring groove 33.

Furthermore, a seal member 3 is provided at the upper end of the rotary valve holder 26.
5 is fitted, and the seal portion 36 of the seal member 35 is pressed against the outer peripheral surface of the valve shaft 27 by the elastic ring 37.

Referring to FIG. 10, the tip of the arm 30 fixed to the upper end of the rotary valve 20 by a bolt 32 is connected via a connecting rod 43 to a control rod 42 fixed to a diaphragm 41 of a negative pressure diaphragm device 40. Ru.

The negative pressure diaphragm device 40 has a negative pressure chamber 44 isolated from the atmosphere by a diaphragm 41.
A compression spring 45 for pressing the diaphragm is inserted therein.

An intake manifold 47 equipped with a compound carburetor 46 consisting of a primary carburetor 46a and a secondary carburetor 46b is attached to the cylinder head 3, and the negative pressure chamber 44 is connected to the intake manifold 47 via a negative pressure conduit 48. connected within.

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 is connected to the negative pressure chamber 4 via an atmospheric conduit 50 on the one hand.
4 and, on the other hand, to 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 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 secondary throttle valve 64 opens. The next throttle valve 64 is also fully opened.

The negative pressure generated in the venturi portion 62 of the primary side carburetor 46a increases as the amount of intake air supplied into the engine cylinder increases, and therefore the negative pressure generated in the venturi portion 62 becomes larger than a predetermined negative pressure. When the engine is operated 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 to open the negative pressure chamber 44 of the negative pressure diaphragm device 40 to the atmosphere.

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 20 is rotated and the branch passage 19 is fully opened.

On the other hand, when the opening degree of the primary throttle valve 63 is small, the negative pressure generated in the venturi part 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 manifold 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 the negative pressure in the negative pressure chamber 44. Since the valve closes when it becomes smaller than , 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 within the negative pressure chamber 44, the diaphragm 41 rises against the compression spring 45, and as a result, the rotary valve 20 is rotated and the branch passage 19 is closed.

Therefore, when the engine is operating at low speed and low load, the rotary valve 20 closes the branch passage 19.

Furthermore, even during high-load operation, if the engine speed is low,
Further, even if the engine speed is high, when the engine is operated under low load, the atmospheric release control 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 19 is closed by the rotary valve 20.

As described above, the rotary valve 20 shuts off the branch passage 19 when the engine is operating at low speed and low load with a small amount of intake air.

Therefore, at this time, a part of the air-fuel mixture sent into the inlet passage A is transferred to the upper wall surface 14 as shown by the arrow in FIG.
．． 15, the other air-fuel mixture collides with the inclined side wall surface 13 of the inlet passage section A, is given a downward force, and moves toward the cylindrical outlet section without turning as shown by the arrow in FIG. 18.

As mentioned above, since the width of the upper wall surface 14 gradually becomes narrower, the flow path of the air-fuel mixture flowing along the earthen wall surface 14 gradually narrows, and thus the speed of the air-mixture flow along the upper wall surface 14 is gradually increased.

Next, this accelerated air mixture flow is transferred to the upper wall surface 15 of the swirl portion B.
In this way, a strong swirling flow is generated within the spiral portion B.

As shown by the arrow, the mixture flowing into the cylindrical outlet part 18 is given a swirling force by this swirling flow, and then the swirling mixture passes through the gap formed between the intake valve 5 and its valve seat and enters the combustion chamber. 4 and generates 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 20 opens, so that part of the air-fuel mixture sent into the inlet passage A flows into the volute B through the branch passage 19 with low flow resistance. sent to.

In this way, when the engine is operated at high speed and under high load, the rotary valve 20 opens, which not only increases the overall flow path area, but also allows some of the air-fuel mixture to flow into the volute part B via the branch path 19 with low resistance. Furthermore, since there is an intake air circulation space 25 having a large cross-sectional area between the lower end of the valve body 29 and the bottom wall 16, high filling efficiency can be ensured.

In addition, by providing the inclined side wall surface 13 in the inlet passage A, a part of the air-fuel mixture sent into the inlet passage A is smoothed onto a smooth curved wall surface without swirling like the air-fuel mixture flowing through a normal intake port. 17 into the cylindrical inlet portion 18, the inflow resistance is reduced, thus further increasing the filling efficiency during high-speed, high-load operation.

To form the helical intake port 6 in the cylinder head 3 as described above, first use a wooden mold to form a core having a helical intake port shape, and then use this core to form the cylinder. A helical intake port 6 is molded within the head 3.

11 to 15 show a helical intake port 6 formed in the cylinder head 3 using a core formed by a two-part wooden mold.

In addition, in FIGS. 12 to 15, straight lines P and Q indicate the dividing line between the upper mold and the lower mold when molding the core.

It can be seen from FIGS. 12 to 15 that the core can be molded using a wooden mold split into two.

As described above, according to the present invention, the core can be molded from a wooden mold split into two, making it extremely easy to manufacture a helical intake port.

In addition, by forming a lower space below the partition wall and further forming an intake air circulation space between the lower end of the rotary valve's valve body and the bottom wall of the intake port, the entire lower space of the intake port can be used like a straight port. Moreover, since there is no rotary valve in the space below this intake port, high filling efficiency can be obtained during engine high-speed, high-load operation.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of the helical intake port seen along the inlet passage, Figure 2 is a sectional plan view of the cylinder head,
Figure 3 is a side cross-sectional view of the helical intake port taken along the branching path, Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 3, and Figure 5 is the line ■-■ in Figure 3. 6 is a sectional view taken along line VI-VI in FIG. 3,
FIG. 7 is a sectional view taken along the line ■-■ in FIG. 3, and FIG. 8 is a perspective view schematically showing the shape of the helical intake port.
FIG. 9 is a side sectional view of the rotary valve, FIG. 10 is an overall view of the rotary valve drive control device, and FIG. 11 is a side sectional view taken along the branching path of the helical intake port during the manufacturing process.
Fig. 12 is a cross-sectional view taken along the line ■-■ in Fig. 11, Fig. 13 is a cross-sectional view taken along the line X-X■ in Fig. 11,
14 is a sectional view taken along the line XIV-XIV in FIG. 11, and FIG. 15 is a sectional view taken along the line xv-xv in FIG. 11. 5... Intake valve, 6... Helical intake port, 13... Inclined side wall surface 19...
- Branch road, 20...Rotary valve, 21...
...Bulkhead.

Claims (1)

[Scope of utility model registration request] In a helical intake port configured with a spiral part formed at the intake station and an inlet passage connected tangentially to the spiral part and extending almost straight, the intake port protrudes downward from the upper wall surface of the intake port. forming a partition wall extending in the flow direction of the air flow in the intake port, forming an inlet passage portion and a branch passage branching from the inlet passage portion on both sides of the partition wall;
A lower space communicating the inlet passage and the branch passage is formed below the partition wall, and the branch passage communicates with the spiral terminal end of the spiral part, and an on-off valve is inserted into the branch passage, and the on-off valve is inserted into the branch passage. A helical intake port, the lower end of which is spaced apart from the common bottom wall of the inlet passageway and the branch passageway to form an inflow air circulation space between the lower end of the on-off valve and the common bottom wall.