JPS6323545Y2 - - 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 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 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. With this helical type intake port, when the engine is operating 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 volute via 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.

The present invention will now 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 section 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 opening/closing insertion hole 17 is bored in the cylinder head 3 and extends through the branch passage 14, and a rotary valve 18 constituting an opening/closing valve is inserted into each opening/closing valve insertion hole 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. Therefore, a groove 19 is formed on the lower wall surface of the branch passage 14 by the opening/closing valve insertion hole 17. Further, an internal thread 20 is screwed into the upper end of the on-off valve insertion hole 17.
A rotary valve holder 21 is screwed onto this internal thread 20. The rotary valve holder 21 has an outer peripheral flange 22 on its outer peripheral wall surface, and this outer peripheral flange 2
A seal member 23 is inserted between the cylinder head 2 and 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-shaped valve body 26 is fixed to the lower end of the valve shaft 25.
An arm 27 is attached to a washer 28 at the upper end of the valve stem 25.
It is fixed with a bolt 29 via. A ring groove 30 is formed on the outer circumferential wall surface of the valve shaft 25 which is located at approximately the same height as the upper end surface of the rotary valve holder 21, and within this ring groove 30 is a C-shaped positioning ring as shown in FIG. 31 is fitted. This positioning ring 31 engages with a conical surface 32 formed on the inner edge of the upper end surface of the rotary valve holder 21 to position the valve body 26 at a predetermined position. On the other hand, a reinforcing frame 3 is provided at the upper end of the rotary valve holder 21.
A sealing member 34 surrounded by 3 is fitted,
The seal portion 34a of the seal member 34 is the seal member 3
The elastic ring 35 inserted onto the outer circumferential surface of the valve shaft 25 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 23 and 34.

As shown in FIG. 12, the rotary valve 18 of each cylinder
The distal ends of the arms 27 are connected to each other by a connecting rod 40, and this connecting rod 40 is connected via, for example, a wire 43 to an accelerator pedal 42 that rotates around a support shaft 41. When the accelerator pedal 42 is not depressed, that is, when the engine is idling, the rotary valve 18 fully closes the branch passage 14, and as the accelerator pedal 42 is depressed, the rotary valve 18 gradually opens, and the accelerator pedal 42 When the rotary valve 18 is depressed, the rotary valve 18 fully opens the branch passage 14. Therefore, it can be seen that the opening area of the rotary valve 18 is proportional to the engine load.

As described above, the rotary valve 18 shuts off the branch passage 14 during engine idling operation. 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. When the accelerator pedal 42 is depressed, the rotary valve 18 opens, and at this time, a small amount of air-fuel mixture flows into the swirl portion B through the branch path 14, so that the swirling flow is slightly weakened. On the other hand, during high-load operation when the accelerator pedal 42 is depressed the most, the rotary valve 18 is fully opened, 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 end edge of the outlet opening 16 of the branch passage 14 is connected to the upper wall surface 13 of the spiral portion B in a substantially flush manner, so that the air-fuel mixture flowing out from the branch passage 14 flows into the spiral portion B.
It collides head-on with the entire air mixture flow swirling along the upper wall surface 13, and decelerates the entire air mixture flow along the upper wall surface 13 of the swirl portion B. That is, among the swirling flows generated in the swirling portion B, the swirling flow along the upper wall surface 13 of the swirling portion B is the strongest, and the entire air mixture flow having this strong swirling force is decelerated. In this manner, when the rotary valve 18 is opened during high-speed, high-load engine operation, not only does the overall flow path area increase, but also the air mixture flow, which has a strong swirling force, is decelerated, resulting in a wide swirling flow. Since it is weakened, 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-load operation.

As described above, according to the present invention, the upper edge of the outlet opening of the branching passage is connected almost flush with the upper wall surface of the spiral part, so that when the on-off valve opens, the air-fuel mixture flowing out from the branching passage is It is possible to decelerate the total air mixture flow that swirls with a strong swirling force along the upper wall surface of the spiral portion, and thus the swirling flow can be greatly weakened, so that high filling efficiency can be obtained. Furthermore, according to the present invention, the flow path control device can be made into an extremely simple structure suitable for practical use.
In this way, the flow path control device can be operated reliably at all times, and the reliability of the flow path control device can be improved.

[Brief explanation of the drawing]

Figure 1 is a plan view of the internal combustion engine according to the present invention, Figure 2 is a plan view of the 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,
FIG. 11 is a plan view of the positioning ring, and FIG. 12 is an overall view of the flow path control device. 5... Intake valve, 6... Helical intake port,
14... Branch road, 18... Rotary valve, 42...
Accelerator pedal.

Claims (1)

[Scope of utility model registration request] In a helical intake port constituted by a spiral portion formed around the intake valve and an inlet passage portion connected tangentially to the spiral portion and extending almost straight, a branch path branched from the inlet passage portion. communicates with the spiral end of the spiral section, the exit opening is formed at the upper end of the side wall surface of the spiral section so as to oppose the swirling flow along the upper wall surface of the spiral section, and the upper edge of the exit opening is connected almost flush to the upper wall surface of the spiral part, and an on-off valve is inserted into the branch passage, and the on-off valve is directly connected to the accelerator pedal so that the opening area of the on-off valve is proportional to the engine load. Type intake port flow path control device.