JPS6226589Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flow path control device for a helical intake port.

A helical intake port typically consists of a spiral formed around the intake valve and an inlet passageway tangentially connected to the spiral and extending generally 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. There is a problem in that the filling efficiency decreases when the engine is operated under high-speed 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 actuator is installed in the branch path. The main helical intake port flow path control device is a helical intake port flow path control device that is equipped with a normally-closed on-off valve that is operated by the engine, 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 by the applicant. 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, this flow path control device only shows the basic operating principle, and therefore, in order to put this flow path control device into practical use, there are various issues in terms of assembly man-hours, ease of manufacturing, reliable operation, and manufacturing cost. Problems remain.

The object of the present invention is to provide a helical intake port flow path control device having a structure suitable for putting into practical use the above-mentioned basic operating principle that has already been proposed by the applicant.

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

Referring to FIGS. 1 and 2, 1 is a cylinder block, 2 is a piston that reciprocates within cylinder block 1, 3 is a cylinder head fixed on cylinder block 1, and 4 is a link between piston 2 and 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, and 8 is a cylinder head 3.
Exhaust ports formed therein are shown respectively. Although not shown in the figure, an ignition plug is disposed within the combustion chamber 4.

3 to 5 schematically show the shape of the helical intake port 6 of FIG. 2. This helical intake port 6 has a flow path axis a as shown in FIG.
It is composed of a slightly curved inlet passage part A and a spiral part B formed around the valve axis of the intake valve 5, and the inlet passage part A is tangentially connected to the spiral part B. As shown in FIGS. 3, 4, and 7, the side wall surface 9 of the inlet passage A near the spiral axis b
The upper side wall surface 9a is formed as an inclined surface facing downward, and the width of this inclined surface 9a becomes wider as it approaches the spiral portion B. As shown in the figure, the entire side wall surface 9 is formed into a downwardly oriented inclined surface 9a. The upper half of the side wall surface 9 is smoothly connected to the peripheral wall surface of a cylindrical projection 11 formed on the upper wall surface of the intake port around the intake valve guide 10 (FIG. 2).
The lower half of the spiral portion B is connected to the side wall surface 12 of the spiral portion B at the spiral end portion C of the spiral portion B. In addition, spiral part B
The upper wall surface 13 is connected to the downwardly inclined wall D at the spiral end C.

On the other hand, as shown in FIGS. 1 to 5, a branch passage 14 having a substantially uniform cross section is formed in the cylinder head 3, branching from the inlet passage part A, and this branch passage 14 is connected to the spiral terminal part C. Connected. Branch road 14
An inlet opening 15 is formed on the side wall surface 9 in the vicinity of the inlet opening of the inlet passage section A, and an outlet opening 16 of the branch passage 14 is formed at the upper end of the side wall surface 12 at the spiral end C. The upper end edge of this outlet opening 16 is connected flush with the upper wall surface 13 of the spiral portion B, and furthermore, this exit opening 16 is arranged so as to face the swirling flow swirling in the spiral direction along the upper wall surface 13 of the spiral portion B. It is formed. An on-off valve insertion hole 17 is formed in the cylinder head 3 and extends through the branch passage 14, and a rotary valve 18 constituting an opening valve is inserted into each of the on-off valve insertion holes 17. Referring to FIG. 9, the on-off valve insertion hole 17 is a cylindrical hole of uniform diameter drilled from above in the cylinder head 3, and the on-off valve insertion hole 17 extends beyond the lower wall surface of the branch passage 14. Extends to a certain extent. A rotary valve holder 21 is fitted into the on-off valve insertion hole 17, and a sealing member 1 made of, for example, an O-ring is provided on the outer peripheral surface of the rotary valve holder 21 and inside the on-off valve insertion hole 17.
9 is inserted. As shown in FIG. 13, each rotary valve holder 21 is fitted and fixed into an opening 20a formed in a mounting board 20, and this mounting board 20 is connected to the head of a cylinder head bolt 22 fixed to the cylinder head 3. It is fixed by a bolt 23. However, it is also possible to fix this mounting board 20 directly to the cylinder head 3. On the other hand, a through hole 24 is bored in the rotary valve holder 21, and a valve shaft 25 of the rotary valve 18 is rotatably inserted into the through hole 24. A thin plate-like valve body 26 is fixed to the lower end of the valve shaft 25, and an arm 27 is fixed to the upper end of the valve shaft 25 with a bolt 29 via a washer 28. Rotary valve holder 2
A ring groove 30 is formed on the outer circumferential wall surface of the valve shaft 25 at approximately the same height as the upper end surface of the valve shaft 1, and an E-shaped positioning ring 31 as shown in FIG. 11 is fitted into the ring groove 30. It will be worn. This positioning ring 31 engages with the top surface of the rotary valve holder 21 to position the valve body 26 at a predetermined position. On the other hand, a sealing member 34 surrounded by a reinforcing frame 33 is fitted to the upper end of the rotary valve holder 21, and a sealing portion 34a of the sealing member 34 has an elastic ring 35 inserted on the outer peripheral surface of the sealing member 34.
is brought into pressure contact with the outer circumferential surface of the valve shaft 25. Therefore, the branch passage 14 is completely isolated from the outside air by the seal members 19, 34. As shown in FIG. 13, each arm 27 has a pin 3 at its tip.
6 is installed. Each of these pins 36 is fixed to the tip of the arm 27 by caulking their lower ends. A small diameter portion 37 is formed at the upper end of the pin 36, and a connecting rod 38 for connecting the tips of the arms 27 to each other is rotatably mounted within this small diameter portion. An E-shaped ring 39 as shown in FIG. 11 is attached to the pin 36 above the connecting rod 38, and this E-shaped ring 39 prevents the connecting rod 38 from falling off. In addition, E
Instead of using the shaped ring 39, a washer 39' is fitted onto the pin 36 above the connecting rod 38 as shown in FIG. 14, and the washer 39' is fixed to the pin 36 by caulking the upper end of the pin 36. You can also.

Referring to FIG. 12, the end of a connecting rod 38 interconnecting the arms 27 of each rotary valve 18 is connected to the tip of a control rod 42 secured to a diaphragm 41 of a negative pressure diaphragm device 40. Negative pressure diaphragm device 40 is diaphragm 4
1, which has a negative pressure chamber 44 isolated from the atmosphere, and a compression spring 45 for pressing the diaphragm is inserted into this negative pressure chamber 44. 1 for cylinder head 3
An intake manifold 47 equipped with a compound type carburetor 46 consisting of a next side carburetor 46a and a secondary side carburetor 46b is attached, and the negative pressure chamber 44 is connected to a negative pressure conduit 48.
The intake manifold 47 is connected through the intake manifold 47 . 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 diaphragm 52
It has a negative pressure chamber 53 and an atmospheric pressure chamber 54 separated by a spacer, and further has a valve chamber 55 adjacent to the atmospheric pressure chamber 54. This valve chamber 55 communicates on the one hand with the negative pressure chamber 44 via an atmospheric conduit 50 and on the other hand with the atmosphere via a valve port 56 and an air filter 57. A valve body 58 for controlling the opening and closing of the valve port 56 is provided within the valve chamber 55, and the valve body 58 is connected to the diaphragm 52 via a valve rod 59.
A compression spring 6 for pressing the diaphragm is provided in the negative pressure chamber 53.
Further, the negative pressure chamber 53 is connected to the bench lily portion 62 of the primary side carburetor 46a via a negative pressure conduit 61.

The vaporizer 46 is a commonly used vaporizer,
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 also fully opens. The negative pressure generated in the bench lily portion 62 of the primary carburetor 46a increases as the amount of intake air supplied into the engine cylinder increases.
Therefore, when the negative pressure generated in the bench lily portion 62 becomes larger than a predetermined negative pressure, that is, when the engine is operated at high speed and under high load, the diaphragm 5 of the atmospheric release control valve 51
2 moves to the right against the compression spring 60, 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 to the atmosphere.
At this time, the diaphragm 41 moves downward due to the spring force of the compression spring 45, and as a result, the rotary valve 18
is rotated to fully open the branch path 14. On the other hand, when the opening degree of the primary throttle valve 63 is small, the negative pressure generated in the bench lily 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 5
8 closes valve port 56. Furthermore like this 1
When the opening degree of the next throttle valve 63 is small, 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 valve closes when the negative pressure in the negative pressure chamber 44 becomes smaller than the negative pressure in the negative pressure chamber 44. Therefore, as long as the atmospheric release control valve 51 is closed, the negative pressure in the negative pressure chamber 44 is transferred to the intake manifold 47.
maintained at the maximum negative pressure generated within. Negative pressure chamber 44
When negative pressure is applied inside, the diaphragm 41 rises against the compression spring 45, and as a result, the rotary valve 18 is rotated and the branch passage 14 is closed. Therefore, when the engine is operating at low speed and low load, the branch passage 14 is closed by the rotary valve 18. In addition,
If the engine speed is low even during high load operation,
Furthermore, 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 bench lily 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 14 is closed by the rotary valve 18. .

As mentioned above, the rotary valve 18 shuts off the branch passage 14 when the engine is operating at low speed and low load with a small amount of intake air. At this time, the air-fuel mixture sent into the inlet passage part A descends inside the swirl part B while swirling along the upper wall surface 13 of the swirl part B, and then flows into the combustion chamber 4 while swirling. A strong swirling flow is generated inside. 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 18 opens, so that part of the air-fuel mixture sent into the inlet passage A flows into the volute part B via the branch passage 14 with low flow resistance. sent to. As mentioned above, the upper edge of the outlet opening 16 of the branch passage 14 is connected flush with the upper wall surface 13 of the spiral part B, so that the air-fuel mixture flowing out from the branch passage 14 flows along the upper wall surface 13 of the spiral part B. It collides head-on with the swirling total air mixture flow and decelerates the total air mixture flow along the upper end surface 13 of the swirl portion B. That is, among the swirling flows generated in the swirling part B, the swirling flow along the upper wall surface 13 of the swirling part B is the strongest,
The entire air mixture flow with this strong swirling force is decelerated. In this way, when the rotary valve 18 opens during engine high-speed, high-load operation, not only does the overall flow path area increase, but the entire air mixture flow, which has a strong swirling force, is decelerated, thereby increasing the swirling flow. Since it is weakened in width, high filling efficiency can be ensured. Further, as described above, by providing the inclined surface 9a, a portion of the air-fuel mixture fed into the inlet passage A is given a downward force, and as a result, this air-fuel mixture flows through the inlet passage A without swirling. Since the fluid flows into the spiral portion B along the lower wall surface, the inflow resistance becomes small, thus making it possible to further improve the filling efficiency during high-speed, high-load operation.

To assemble each rotary valve 18 into the cylinder head 3, first fix each rotary valve holder 21 to the mounting board 20, then fit the connecting rod 38 onto the pin 36 attached to the tip of each arm 27. The rotary valve holder 21 and the connecting rod 38 are integrally mounted on the mounting board 20, and then each rotary valve holder 21 is inserted into the corresponding opening/closing valve insertion hole 17.
These rotary valve holders 21 are pushed down together with the mounting board 20, and then, after each rotary valve holder 21 is completely inserted into the corresponding opening/closing valve insertion hole 17, the mounting board 20 is inserted into the cylinder with the bolt 23. Fasten to head 3.

According to the present invention, by integrally mounting the rotary valve holder on the mounting board, the fully closed and fully open positions of each rotary valve body can be synchronized with each other before the rotary valve holder is mounted on the cylinder head. Since the rotary valve body can be easily adjusted, the fully closed position and the fully open position of the rotary valve body can be accurately positioned, and furthermore, the work of assembling the rotary valve holder to the cylinder head is extremely easy.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an internal combustion engine according to the present invention, Fig. 2 is a plan view of an internal combustion engine according to the present invention;
The figure is a cross-sectional view taken along the - line in Figure 1.
The figure is a perspective view showing the shape of a helical intake port.
Fig. 4 is a plan view of Fig. 3, Fig. 5 is a side sectional view taken along the branch road in Fig. 3, Fig. 6 is a sectional view taken along the - line in Fig. 4, and Fig. 7. is a sectional view taken along the - line in Fig. 4, Fig. 8 is a sectional view taken along the - line in Fig. 4, Fig. 9 is a side sectional view of the rotary valve, and Fig. 10 is a sectional view taken along the - line in Fig. 9. Side view,
Figure 11 is a plan view of the positioning ring, Figure 12 is an overall view of the flow path control device, and Figure 13 is XII of Figure 12.
Figure 14 is a side sectional view taken along line -XII.
FIG. 3 is a side sectional view showing another embodiment of a part of FIG. 3; 5... Intake valve, 6... Helical intake port,
14... Branch road, 18... Rotary valve, 20...
Mounting board, 21... Rotary valve holder, 25...
... Valve stem, 26... Valve body.

Claims (1)

[Scope of utility model registration request] In a helical intake port configured with a spiral portion formed around the intake valve and an inlet passage portion that is tangentially connected to the spiral portion and extends almost straight, the spiral portion is branched from the inlet passage portion and is connected to the spiral portion. A branch passage communicating with the spiral terminal end of the valve is formed in the cylinder head, and an on-off valve insertion hole extending across the branch passage is formed in the cylinder head, and a plurality of on-off valve insertion holes to be inserted into each on-off valve insertion hole are formed in the cylinder head. A helical intake type in which the rotary valve holders are fixed to a common mounting board, the mounting board is fixed to the cylinder head, and each rotary valve holder inserted into the corresponding opening/closing valve insertion hole is held by the mounting board. Port flow control device.