JPS6011206B2 - Internal combustion engine intake system - Google Patents

Description

[Detailed description of the invention] The present invention relates to an intake system for an internal combustion engine.

Generally, when an internal combustion engine is operated under low load, the filling efficiency of the air-fuel mixture into the combustion chamber is low, resulting in low flame propagation efficiency and unstable ignition.

As a result, the thermal efficiency of the internal combustion engine is low, and the engine tends to run smoothly, especially when a lean mixture is used. For this reason, conventional efforts have been made to alleviate these problems by encouraging the air-fuel mixture to flow, such as by installing a large squish area in the combustion chamber or by designing the combustion chamber into a shape that is more likely to generate swirl, but this is still not enough. . This invention was made based on the above circumstances, and when the amount of intake air is small such as during low-load operation, turbulence is generated in the intake air flow near the intake valve to encourage the air-fuel mixture to fly. An intake bag for internal combustion engines that increases propagation efficiency and stabilizes ignition, enables stable combustion even in lean mixture operation, and does not increase intake resistance even when transitioning to high-load operation. It is an attempt to provide a fake.

That is, in order to achieve the above-mentioned object, the present invention provides a structure in which, in the vicinity of the intake valve, the intake passage is connected to the combustion chamber through the intake valve.
A rod-shaped recessed member with a part of the peripheral wall protruding into the intake passage is provided so as to be rotatable around its axis, and a portion of the peripheral wall of this recessed member facing into the intake passage is provided with a rotatable member. By providing a notch portion having a surface that is continuous with the inner wall surface of the above-mentioned intake passage by rotating the projecting and recessing member,
The present invention is characterized in that the cutout portion is made to protrude and retract within the intake airway.

An embodiment of the present invention will be described below based on the drawings.

E in the figure is an internal combustion engine, and this engine E has a combustion chamber 4 formed by a cylinder 1, a piston 2 and a sill head 3 which are slidably adhered to the cylinder 1.

Although it is not clear in the figure, this combustion chamber 4 is a two-ball type combustion chamber and is equipped with a squish area. And this combustion chamber 4
is communicated via an intake valve 5 to an intake passage 6 and via an exhaust valve 7 to an exhaust passage 8. Also, 9 is a spark plug,
It is provided at the top of the combustion chamber 4. The intake passage 6 is
It passes through an air cleaner (not shown) through a suction pipe 10, a passage pipe 11, and a vaporizer 12. The vaporizer 12
A venturi 13 provided in the intake passage 6 is provided with a piston 14 for adjusting the degree of opening of the venturi 13, and a needle valve 15 attached to the piston 14 controls the opening of the needle jet 16. ing. A throttle valve 17 is provided downstream of the venturi 13, and a control valve 18 is provided in the lotus Z passage pipe 11 located downstream of the throttle valve 17. The valve shafts 17a and 18a of the throttle valve 17 and the control valve 18 are connected to levers 19 and 2, respectively.
1 is connected to Z. The floating device 21 is arranged in a case 2.
A slider 23 is provided in the slider 23, and the slider 23 is actuated by an operator 24 such as a throttle grip, and the wire 19a on the throttle valve 17 side is connected to the slider 23 without causing any play. The wire 20a on the control valve 18 side is connected to the slider 23 so that the control valve 18 side is connected to the slider 23 so as to be operated in accordance with the displacement of the information slider 23 caused by the operation of the operator 224.
It is connected with the slider 23 with play, and follows the slider 23 after the slider 23 has been displaced by a predetermined amount. Therefore, the control valve 18 will not open at all until the throttle valve 17 is opened by a predetermined amount, for example about 50 degrees, by operating the operator 24, and if the throttle valve 17 is opened any further, the control valve 18 will be opened later. , and is configured such that when the throttle valve 17 is fully opened, the control valve 18 is also fully opened. Note that the throttle valve 17 and the control valve 18
Although not shown in the drawings, each of them is adapted to automatically rotate and return to its original state by a return spring to close the intake passage 6. Also, 2
A small intake passage 5 is formed in a smaller depression than the intake passage 6 and is configured to bypass the control valve 18.
In other words, the upstream machine of this small intake pilgrimage 25 is the throttle valve 17.
The bottom of the intake passage 6 located between the intake passage 6 and the control valve 18 is connected to a counterfeit mouth body 26 at the downstream end, and the nozzle body 26 is connected to the cap of the intake valve 5 when the valve is open, for example. It is opened □ so as to face the shaped part. Note that the nozzle body 26 may be opened directly toward the circumferential direction within the combustion chamber 4 . However, the intake passage 6
, a projecting and recessing member 27 is provided at a position upstream of the entrance part of the nozzle body 26 and as close to the combustion chamber 4 as possible. The projecting and recessing member 27 is made of a rotatable bamboo material that is mounted in the wall of the intake passage 6 so as to intersect with the axial direction of the intake passage 6, and a part of the side wall of this bamboo material has a As shown in FIGS. 3A and 3B and FIGS. 4A and 4B, a notch 28 is formed with a surface 27a that fits into the inner wall surface of the intake passage 6 when rotated. And this plunge village 27
is designed to cause turbulence in the intake flow in the intake passage 6 when the side surface portion 27b facing away from the notch 28 protrudes into the intake passage 6, and is also rotated so that the notch 28 When the notch 28 is directed toward the inside of the intake passage 6,
The surface 27a is continuous with the inner wall surface of the intake passage 6 to prevent turbulence from occurring in the intake flow. A pulley 29 is provided at the end of the projecting and recessing member 27 extending outside the intake passage 6, and one end of a wire 30 wound around the pulley 29 is connected to the slider 23 of the floating device 21 with no play. They are connected by having . This projecting and recessing member 27 is connected to the operating element 24
The throttle valve 17 is opened by the operation of the slider 23 caused by the operation of the slider 23, and the control valve 18 is subsequently opened.
is rotated after being opened a predetermined amount □, and this rotational movement causes the notch 28 to point toward the intake passage 6, and the side surface portion 27b facing away from the notch 28 to face the intake passage 6. He is now being expelled from the university. Note that 31 is a coil spring for rotating and returning the projecting and retracting member 27. The operation of the above embodiment with such a configuration will be explained.

Since the control valve 18 is closed during idling operation when the operator 24 is not operated, or during low-load operation when the operator 24 is operated slightly and the throttle valve 17 is opened slightly, the control valve 18 is closed.
During the intake stroke in which the intake valve 5 is involved, the downstream side of the intake passage 6 from the control valve 18 becomes negative pressure, so the air-fuel mixture that has passed through the throttle valve 17 passes through the small intake passage 25 and reaches the nozzle body 26. It is ejected into the intake passage 6.

This air-fuel mixture then hits the cap-shaped portion of the 0-intake valve 5 and changes direction as shown by the arrow, producing a high-speed swirl within the cylinder 1 as shown in FIG. In this way, the velocity of the intake air jetted into the intake passage 6 through the small intake passage 25 increases as the pressure inside the intake passage 6 is low during low-load operation, so that the swell generated in the combustion chamber 4 increases. is faster. This swirl remains even when engine E reaches the compression stroke, so at the end of the compression stroke the spark plug 9
When the air-fuel mixture is ignited by Completes combustion in a short time,
There is no residual combustion, and the unsmooth operation caused by instability of the flame propagation speed can be improved, and unburned and incompletely burned components contained in the exhaust gas are also reduced. Furthermore, even in a lean mixture where flame propagation is relatively smooth,
The above-mentioned high swirl speeds up the flame propagation speed, thereby promoting smooth combustion. Next, when the operator 24 is operated to increase the engine output and the throttle valve 17 is opened to 5° or more, the control valve 18 is opened later than the throttle valve 17.

At this time, the small intake passage 25 is approaching a saturated state, and the air-fuel mixture begins to flow through the control valve 18 together with the small intake passage 25. As the pressure of the control valve 18 increases, the pressure inside the intake passage 6 increases, so the small intake passage 25
The flow rate of intake air supplied from the However,
As shown in FIGS. 3a and 3b, a side portion 27b of a protruding and recessed member 27 protrudes downstream of the control valve 18, that is, in the intake passage 6 close to the intake valve 5. The air-fuel mixture flowing through the intake passage 6 flows through this side portion 27.
A part of it hits b, generating turbulence. This turbulent flow distorts the air-fuel mixture in the intake passage 6, and this turbulent flow is also transmitted into the combustion chamber 4, causing a swirl in the combustion chamber 4. Therefore, even when the engine output increases in the initial stage when the control valve 18 is opened, that is, when the air-fuel mixture filling efficiency is relatively low during the transition period from the low-load operating range to the medium-load operating range, the protruding portion Since the swirl is generated by the village 27, the flame propagation speed becomes high, combustion occurs in a short time, and smooth and stable operation becomes possible. Furthermore, by operating the operator 24, the throttle valve 17 and the control valve 1 are
8, the projecting and recessing member 27 is rotated accordingly, and the side portion 27b that had been projecting into the intake passage 6 is moved out of the intake passage 6, as shown in FIGS. 4a and 4b. , instead of this, the notch 28 is exposed.

When this state is reached, the filling efficiency of the air-fuel mixture is high and the squish area also functions in a left-handed manner, so the combustion state of the intake air improves, and the actions of the small intake passage 25 and the protruding member 27 are no longer necessary. Do not rely on high output driving castle. At this time, the side surface portion 27b of the projecting and recessing member 27 is removed from the intake passage 6, and the surface 27a of the notch 28 is opposed to the intake passage 6 instead.
Since the intake passage 6 is continuous with the inner wall surface of the intake passage 6, there are no irregularities or the like that would disturb the flow within the intake passage 6, and therefore, there is no obstacle to the flow of the air-fuel mixture. In addition, in the above example,
Although the control valve 18 and the small intake passage 25 are provided to smooth and stabilize combustion during low-load operation such as idling, the present invention is not limited to the above-mentioned embodiments, and the control valve 18 and the small intake passage 25 are Even in an engine that does not have a valve 18 or a small intake passage 25, the air-fuel mixture during low-output operation is caused to flow through the action of the projecting and recessing member 27, and is smoothly diffused into the combustion chamber 4, thereby improving combustion efficiency. It is something that can be done. According to the present invention described in detail above, when the amount of intake air is small, such as during low-load operation, the protruding and retracting member causes turbulence in the intake air flow and prevents the intake air from flowing.
Swirl can be generated within the combustion chamber, which stabilizes the flame propagation within the combustion chamber and increases the flame propagation speed, resulting in smooth and stable combustion.

Therefore, it prevents a decrease in combustion speed due to a decrease in charging efficiency, improves thermal efficiency, reduces emissions of air pollutants due to unburned and incomplete combustion, and stabilizes combustion even with a lean mixture. It can be done by When the amount of intake air increases due to the transition to high-load, high-output operation, the projecting and recessing member is removed from the intake passage, and the surface of the notch is instead faced and continuous with the inner wall surface of the intake passage. There are no unevenness or the like in the intake passage that would disturb the flow of intake air, and therefore there is no resistance to intake air, and a predetermined amount of intake air can be reliably supplied. Moreover, by making the above-mentioned protruding member rotatable within the intake passage, even when the intake negative pressure fluctuates during engine operation, the amount of protruding and submerging of the protruding part does not fluctuate unstablely, and the intake air This has the advantage of not unnecessarily interfering with the flow of water.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view of the engine, FIG. 2 is a sectional view taken along the Rolo line in FIG. 1, and FIG. 3 is a sectional view of the engine.
, b show the main parts, FIG. 3 a is a sectional view taken along line mA-mA in FIG. 1, FIG. 3 b is a sectional view taken along line mB-mB in FIG. 3 a, and FIGS. 4 a, b 3A and 3B are diagrams showing the operating states of FIGS. 3a and 3b, respectively. 4... Combustion chamber, 5... Intake valve, 6... Intake passage, 17... Throttle valve, 18... Control valve, 25... Small Intake passage, 27... protruding and submerging member,
27a...surface, 28...notch, 27b...
...Side part. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A rod-shaped protruding and recessing member having a part of its peripheral wall protruding into the intake passage is provided in the vicinity of the intake valve in the intake passage connected to the combustion chamber via the intake valve, so as to be rotatable around its axis. At the same time, the circumferential wall of the portion of the protruding and recessing member facing into the intake passage is provided with a notch having a surface that is continuous with the inner wall surface of the intake passage when rotated, and when the protruding and retracting member is rotated, When the notch protrudes and retracts into the intake passage and the amount of intake air flowing through the intake passage is small, the peripheral wall on the side facing away from the notch protrudes into the intake passage, causing turbulence in the intake air flow. An intake system for an internal combustion engine, wherein in the state where the amount of intake air is large, the peripheral wall is withdrawn from the intake passage so that the surface of the cutout portion is continuous with the inner wall surface of the intake passage.