JPS60256515A - Volute type intake-air port in four-cycle engine - Google Patents

Abstract

PURPOSE:To obtain a satisfactory intake-air inertia over the entire operating range of a four cycle engine to enhance the charge effect of the four cycle engine, by providing a projecting piece which is projected toward a forward stream side space in a volute type intake-air port swirl stream generating chamber, and by controlling the projecting amount of the projecting piece in accordance with the rotational speed of the engine by use of an extending and retracting amount adjusting means. CONSTITUTION:A volute shape intake-air port spirally communicates the terminal end section of an intake-air inlet port part 15 with the peripheral surface 14a of a swirl stream generating chamber 14, and an intake-air outlet port 16 is opened to the lower end surface of the swirl stream generating chamber 14. In this arrangement, there is provided a projecting piece 20 for guiding intake-air from the intake-air inlet port part 15 to the intake-air forward stream side space 14b remote from the center axis 21 of the swirl stream generating chamber 14 so that the projecting piece 20 is projected into the space 14b from the terminal end section of the inner circumferential side surface 15b of intake-air in the vicinity of the center axis 21 of the swirl stream generating chamber 14 in the inner peripheral surface 15a of the intake-air inlet passage 15. Further, the movement of a governor lever 27 for a governor 26 is transmitted through an extending and retracting amount adjusting means 23 including a wire 25, and therefore, the projecting piece 20 is controlled so that its projecting length is short in a high speed range while its length is long in a low speed range.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention belongs to the technical field of volute intake boats for four-stroke engines.

<Prior art> The spiral intake boat provides a strong turning force to the intake air, and
In order to provide characteristics that increase charging efficiency, the basic structure is that the intake air flows into the swirling flow generation chamber through the intake inlet passage in a spiral manner to provide swirling force, and then flows forcefully into the combustion chamber from the intake outlet. I'm trying to rotate it.

However, when the intake valve is closed, the intake air that advances through the intake port due to inertia is bounced back by the intake valve and flows backward, and in the early stages of opening the intake valve when the intake and exhaust valves overlap, high-temperature, high-pressure combustion exhaust gas also flows backward. However, since these backflows easily spread from the swirl flow generation chamber to the intake inlet passage, the inertial effect of the intake air is reduced, and the swirl velocity and filling efficiency of the intake air cannot be increased as expected.

In addition, as the inertia effect decreases, the negative intake pressure in the swirl flow generation chamber becomes excessive after the valve is opened, and lubricating oil flows into the swirl flow generation chamber along the intake valve shaft, causing oil to flow down, worsening combustion. This has the disadvantage of causing carbon sticks on the intake valve.

In order to eliminate this drawback, the present applicant previously proposed what is shown in FIG.
.

That is, the protruding piece 20 that guides the intake air from the intake inlet passage 15 to the space 14b on the upstream side of the intake air from the axis 21 of the swirling flow generation chamber 14 is placed on the peripheral wall surface 15a of the intake inlet passage 15 of the swirling flow generation chamber 14. The terminal end of the inner circumferential side surface 15b of the intake air near the axis 21 is inserted into the upstream space 14b of the swirling flow generating chamber 14, and the protruding piece 20 is provided only in the upper half of the swirling flow generating chamber 14, and the protruding piece 20 is provided only in the upper half of the swirling flow generating chamber 14, and the protruding piece 20 is provided only in the upper half of the swirling flow generating chamber It is constructed by opening up the section as an open space.

As a result, the protruding piece 20 catches the backflow that occurs when the valve closes and overlaps, and prevents it from spreading to the intake inlet passage 15, thereby increasing the inertial efficiency of the intake air and improving the spiral speed and filling of the intake air. In addition to increasing the efficiency, by trapping the backflow pressure in the swirling flow generation chamber 14 with the protruding piece 20 when the valve is opened, and by not creating excessive intake negative pressure in the swirling flow generation chamber after the valve is opened, the oil By preventing the fuel from descending, we were able to eliminate the deterioration of combustion performance and the occurrence of carbon sticks.

(3□71. Iyu, Yowoo, □5□) 1.;.

Since the protruding piece 20 was cast integrally with the cylinder head and formed to a certain length, the protruding piece 20 works effectively in the set speed range of the engine that matches the length of the protruding piece 20. The problem remains that the effect is halved in both low-speed and high-speed rotation ranges.

That is, when driving in a low J vehicle rotation range, as the unit time of the combustion cycle becomes longer, the overramp time becomes longer, and the time and amount of exhaust gas flowing backward increases, so the protruding piece 20 can sufficiently catch the exhaust gas. As a result, the air leakage becomes difficult and spreads to the intake inlet passage 15. Moreover, since the amount of intake air is reduced and the intake inertia is small, the influence of the backflow becomes large, weakening the intake inertia.

Conversely, when operating in a high-speed rotation range, the protruding piece 20 creates a large intake resistance against a large amount of intake air, impairing intake inertia.

It is an object of the present invention to solve such problems and to make the protruding piece 20 work properly at all times to improve intake inertia regardless of the same point range.

<Means for solving the problem> In order to achieve the second object, the present invention is configured such that the protruding piece can be adjusted forward and backward from the intake inlet passage toward the upstream side space of the swirling flow generation chamber by a forward and backward adjusting means. It is characterized by things.

<Operation> When the engine is used in a high speed rotation range, the length of the protruding piece protruding into the swirling flow generation chamber is adjusted to be shorter using the advance/retreat adjustment bar. This prevents a large amount of intake air from being subjected to large intake resistance by the protruding piece.

Also, when using in a low speed rotation range, adjust the protrusion dimension of the protrusion piece to be longer. As a result, even a large amount of combustion exhaust flowing back is sufficiently caught by the long protruding pressure, and does not spread to the intake inlet passage.

<Example> Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional front view of the head portion of a water-cooled diesel engine, FIG. 2 is a schematic side view of the engine, and FIG. 3 is a partially cutaway perspective view of the intake boat.

This engine 1 has a fuel tank 3 and a radiator 4 placed and fixed on the left and right sides above a crankcase 2.

A cylinder 6 that slidably accommodates a piston 5 is installed inside the crankcase 2, and a combustion chamber 8 covered by a cylinder head 7 is formed inside the cylinder 6 and above the piston 5.

As shown in FIG. 1, the cylinder head 7 is formed with an exhaust passage 9 and an intake passage 10 that communicate with a combustion chamber 8.
The exhaust outlet 11 communicates with the 77 channel 12, and an air cleaner 13 is connected to the starting end of the intake passage 10. - The intake passage 10 has a terminal end at the circumferential surface 1 of the swirl flow generation chamber 14.
．． 4a, and an intake outlet 16 opening into the combustion chamber 8 at the terminal end of the swirling flow generating chamber 14 is opened and closed by an intake valve 17.

1 1"・Intake 11 passage 1511 is connected tangentially to the swirling flow generation chamber 14°, and the intake valve 1
7 overlaps the exhaust valve 19 and the combustion exhaust gas flowing back from the open light combustion chamber 8 to the swirling flow generating chamber 14 flows into the intake inlet passage 1.
A plate-shaped projecting piece 20 is provided toward the upper half of the swirling flow generating chamber 14 to prevent the intake air from flowing into the swirling flow generating chamber 14 and to guide the intake air flowing through the intake inlet passage 15 to swirl it in the swirling flow generating chamber 14. (See Figures 1 and 3).

The lower part of the protruding piece 20 is provided with the intake air passage 1.
0 from the axis 21 of the swirl flow generation chamber 14 to the reverse flow side space 14c of the intake air from the lower part of the terminal side of the inner side surface 15b of the intake inlet passage 10. It is formed in a convex shape that gradually recedes from the axis 21 toward the reverse flow side space 14c (see FIG. 4).

When the divided flow guide surface 18a is formed in this way, the main flow A guided by the protruding piece 20 swirls in the swirl flow generation chamber 14, and then is sucked into the combustion chamber 8, and a large amount of air flows inside the combustion chamber 8. The divided flow B, which forms a swirling flow and flows at the bottom of the intake passage 10, is guided by the divided flow guide surface 18a as shown in FIG.

In addition, as shown in FIG. 7, since the swirling flow formed by the main stream A is twisted, the swirling flow formed in the combustion chamber 8 becomes a swirling flow twisted with respect to the swirling direction.

The protruding piece 20 is located on the inner peripheral side surface 15 of the intake air near the axis 21 of the swirling flow generation chamber 14 among the peripheral wall surface 15a of the intake inlet passage 15.
1) Downstream side space 14 of one end A-L swirling flow generation chamber 14
A sliding groove 22 is formed in the thick wall 7a of the cylinder head 7 toward the direction b, and the movement of the cylinder head 7 is adjusted forward and backward within the sliding groove 22 by a forward/backward adjustment means 23.

The advance/retreat adjusting means 23 pushes out and biases the end of the protruding piece 20 in the sliding groove 22 with a spring 24, and also presses the bina lever of the speed governor 26 via a release wire 25 fixed to the end of the protruding piece 20. It is configured so that the protruding piece 20 can be adjusted forward or backward in two steps.

The speed governor W26 is a centrifugal type with a governor force of a vane 28 and a governor spring 3 whose tension is adjusted by a speed setting lever 29.
The control rack 32 of the fuel injection pump 31 is adjusted by the governor lever 27 in balance with the zero tension, and the end of the release wire 25 is connected to the vinyl lever 2f.

Intake inlet passage 15 and swirling flow generation chamber 1 below the protruding piece 20°
As shown in FIG. 3, the communicating portion 18 with the combustion chamber 8 is formed on a smooth rounded flow dividing guide surface 18a, and flows from the intake inlet passage 15 through the reverse flow space 14c of the swirl flow generation chamber 14.
This is to improve the agitation of the intake air.

The protruding piece 20 configured as described above is used because the tension of the governor spring 30 is weak in the low speed rotation range of the engine 1.
The vinyl lever 2f is located on the fuel reduction side (left side in the figure), and the release wire 25 connected to the vinyl lever 2f is let out, so that the protruding piece 20 is moved by the spring 30 as shown by the imaginary line in Figure 1. It protrudes into the upstream space 14b of the swirling flow generation chamber 14. When the protruding piece 20 protrudes into the swirling flow generation chamber 14 in this manner, the ventilation area at the tip portion 20a of the protruding piece 20 is narrowed, and the flow velocity is reduced even when the engine 1 is running at low speed, with a small amount of intake air flowing through the intake inlet passage 15. In addition, a sufficiently strong swirling flow is generated in the swirling flow generating chamber 14. Furthermore, when the engine 1 rotates at low speed, the time for the intake valve 17 to wrap around the exhaust valve 19 and open is longer in proportion to the rotational speed, and the amount of backflow of the combustion exhaust gas from the combustion chamber 8 to the swirling flow generation chamber 14 increases. However, since this is received by the protruding piece 20 that largely protrudes from the upper half of the swirling flow generation chamber 14, the intake inlet path j by the combustion exhaust gas is
The intake inertia within 5 is not disturbed. Next, in the high-speed rotation range of the engine 1, the tension of the governor spring 30 is strong, the governor lever 27 is positioned on the fuel increasing side (right side in the figure), and the release wire 25 is retracted, so that it protrudes into the swirling flow generation chamber 14. The amount of protrusion of the protruding piece 20 decreases as shown in the solid line diagram in FIG. In this way, when the amount of protrusion of the protruding piece 20 is small, the ventilation cross-sectional area at the tip portion 20a of the protruding piece 20 becomes large, and a large amount of intake air required during high-speed rotation is drawn into the swirling flow generating chamber 14 without resistance. Then, turn at ν 0 1
When the amount of protrusion of the protruding piece 20 is small, backflow of combustion exhaust gas from the combustion chamber 8 becomes a problem. The opening time of the valve 17 is short in proportion to the rotational speed of the engine 1, and since the amount of combustion exhaust gas flowing back is small, it does not affect the intake inertia flowing through the intake inlet passage 15.

In the dominant embodiment, the projecting piece 20 is configured to be interlocked with the speed governor 2 via the release wire 25, but the release wire 25 may be replaced with a link.

In addition, the protruding piece 20 is attached to the speed setting lever 29 of the speed governor 26.
It may be made to be linked with the swinging operation of the protruding piece, or the forward and backward movement may be adjusted using a dedicated lever for operating the protruding piece, although not shown in the drawings.

<Effects> Since the present invention is configured and operates as described above, it has the following effects.

In other words, when using Ennon in a high speed rotation range, the protruding piece is adjusted to be short so that a large amount of intake air does not receive large intake resistance at the protruding piece4, and conversely, when using the Ennon in a low speed rotation range, the protruding piece is shortened. The reinforcement is long so that even a large amount of combustion exhaust gas flowing backward can be sufficiently caught by the long protruding piece, so that it does not spread to the intake inlet passage.

As a result, regardless of whether the Ennon is operated at high or low speeds, the protruding piece always works effectively to increase the inertial efficiency of the intake air, increasing the vortex velocity and filling efficiency of the intake air. It prevents oil from dripping and eliminates the deterioration of combustion performance and the occurrence of carbon stains and 7-strokes.

In addition, when building a high-speed engine and a low-speed engine, the structure, shape, and dimensions of the spiral intake boat can be made the same, and all you need to do is adjust the protruding dimension of the protruding piece. It is possible to increase the productivity of multiple models of engines with different rotational speeds and reduce manufacturing costs.

In addition, a diverting guide surface 18a that guides the intake air from the intake passage 15 to the reverse flow space 14c of the intake air from the axis 21 of the swirling flow generating chamber 14 through the open space below the protruding piece 20 is provided in the intake inlet passage 15. When forming a smooth convex curved surface that gradually recedes from the lower half of the terminal side of the inner circumferential side surface 15b toward the reverse flow side space 14c, the main flow of intake air flows forcefully across the swirling flow generation chamber. As the combustion engine begins to swirl, the diverted components of the intake air flow along the diverter guide surface and then flow tangentially into the mainstream, imparting torsional rotation to the swirling mainstream, further enhancing the agitation and mixing within the combustion chamber and improving combustion performance. It can be improved.

[Brief explanation of drawings]

1 to 7 show embodiments of the present invention, in which FIG. 1 is a longitudinal sectional front view of the head portion of a water-cooled diesel engine, and FIG.
Figure 3 is a schematic side view of the engine, Figure 3 is a partially cutaway perspective view of the intake boat, Figure 4 is a side view of the main part taken vertically below the protrusion, and Figure 5 is a schematic perspective view showing the main flow. , FIG. 6 is a schematic perspective view showing a branch flow, FIG. 7 is a schematic perspective view showing a combined flow of the main stream and the branch flow, and FIG. 8 is a view equivalent to FIG. 3 showing a conventional example. Death... Combustion chamber, 14... Swirling flow generation chamber, 14a...
14 peripheral surface, 14b... 14 upstream side space, 14c...
...14 reverse flow side space, 15...intake inlet passage, 15
a... Peripheral wall surface of 15, 15b... Inner peripheral side surface of 15, 16... 8 intake ports, 20... Projecting piece, 21...
Axial center, 23...Advance/retreat adjustment means. Patent applicant Kubota Iron Works Co., Ltd. 114 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. The terminal end of the intake inlet passage 15 is spirally connected to the circumferential surface 14a of the swirling flow generation chamber 1.4, and an intake outlet 16 is provided at the lower end surface of the swirling flow generation chamber 1.4. , the intake air is configured to swirl from the intake inlet passage 15 through the swirl flow generation chamber 14 and the intake outlet 16 in the combustion chamber 8, and The protruding piece 20 guided to the upstream space j4b is attached to the peripheral wall surface 15a of the intake inlet passage 15.
Inner circumference 1 of the intake air near the axis 21 of the swirling flow early maturation chamber 14
) The projecting piece 20 is inserted into the upstream space 14b of the swirling flow generation chamber 14 from the terminal end of the side surface 15b, and the protruding piece 20 is inserted into the swirling flow generation chamber 14.
The spiral-shaped intake bow H of a four-cycle engine is provided only at the upper part of the bow H, and the lower half thereof is opened as an open space. A spiral intake boat 2 for a four-cycle engine is characterized in that it is configured to be able to move forward and backward toward the upstream space 14b using a forward and backward adjusting means 23. Intake air is transferred from the intake passage 15 to the open space below the protruding piece 2o. A branching guide surface 18a that guides the intake air from the axis 21 of the swirling flow generation chamber 14 to the reverse flow space 14c is connected to the reverse flow side space 14c from the lower half of the terminal side of the inner circumferential side surface 15b of the intake inlet passage 15. A spiral-shaped intake boat for a T-cycle engine according to claim 1, wherein the intake boat is formed into a smooth convex curved surface that gradually recedes.