JPS6119959A - Carburetor - Google Patents

Abstract

PURPOSE:To maintain a proper air-fuel rtio all the time, by installing a conical valve body, opening or closing in response to motion of an accelerator and doing on-off operations according to suction pressure, inside a Venturi tube, while regulating the valve body operating suction pressure with the atmosphere to be controlled according to an engine operating condition. CONSTITUTION:A circular truncated cone 3 being locked to a shaft 31, which moves up and down by dint of a turning shaft 35 interlocking with an accelerator, is set up in the center of a Venturi where fuel from a float chamber 8 is fed via a pipe 72, a valve 71, a pipe 19 and a nozzle 4. A lower surface of the cone 3 is provided with a piston 32, while this cone 3 moves up and down according to negative pressure as well by means of suction pressure inside the piston 32 balancing with force of the spring supported on the top of a fixed plate 30. A cylinder chamber 17 inside the piston 32 leads the atmosphere inside via a pipe 10, which atmospheric pressure is controlled by a valve to be opened or closed according to an engine operating condition. A control valve 71 installed in the fuel feed pipe 72 is interlocked with an accelerator interlocking shaft 35.

Description

Detailed Description of the Invention [Technical Field 1] The present invention relates to a carburetor for supplying a mixture of fuel and air to an internal combustion engine, particularly an automobile internal combustion engine, and which has an annular variable venturi. related to things.

[Background Technique 1 @ 1 In a vaporizer with an annular variable bench, a bench area is usually formed between an annular orifice and a cone, and the area of the venturi is changed by moving the cone in its axial direction. However, in order to move this cone, conventionally the cone was connected to the accelerator, and the cone moved only in conjunction with the accelerator, changing the venturi area, and the negative pressure of the intake manifold was changed. There was one in which the cone moved in response to the change in bench area. However, both of these have the problem that it is impossible to constantly supply a mixture at an appropriate mixture ratio required by the internal combustion engine.

[Objective of the Invention 1] The present invention has been made in view of the above-mentioned points, and its object is to provide a carburetor that can always supply a mixture at a good mixing ratio.

[Disclosure 1 of the Invention] The present invention provides a housing having a cylindrical air passage passing through the upper and lower sides, a throat portion projecting into the air passage, and an annular orifice opening at the inner peripheral edge of the throw 1 portion.
This carburetor is equipped with a throttle cone that is coaxial with the throat part and reciprocally movable in the up and down axial direction to form an annular variable pinch area between it and the throat part, and the cone is installed in the intake manifold. It is characterized by having a negative pressure chamber that is suction-driven according to the negative pressure value of the negative pressure chamber, and a control valve that controls the amount of communication between the negative pressure chamber and the atmosphere in conjunction with the accelerator. This allows the cone to be controlled by negative pressure at the intake and manufacturer ortho, and at the same time this negative pressure can be controlled by the accelerator.

The present invention will be described in detail below based on the illustrated embodiments. −
) part 2 and an annular orifice 4 that opens at the inner peripheral edge of the throat part 2. A throttle cone 3 forming an annular variable venturi is provided on the housing 1, and a float chamber 8 is integrally provided on the side surface of the housing 1. A cone 3 having a substantially conical outer shape is disposed in the center of the housing 1 so as to be movable in the axial direction below -L, and the throat portion provided on the inner circumferential surface of the housing 1 A circular venturi is formed between the two.

In addition, at the minimum inner diameter part of the lower part 2, an annular orifice 4 communicating with the 70-hole bumper 8 is formed to be open over the entire circumference, and the water flows down through the open venturi between the throat part 2 and the cone 3. The negative pressure generated by the air flow 1 causes fuel to be sucked out into the air passage through the annular orifice 4. The cone 3 moves downward when the accelerator pedal is depressed in response to the accelerator pedal, and is also sucked and driven downward by the negative pressure in the negative pressure chamber 7 communicating with the intake manifold. By moving the cone 3, the venturi area increases.

To explain in more detail, the housing 1 has a shape fk consisting of an upper housing 11 and a lower housing 12, and above the upper housing 11 is an air cleaner 13.
is connected to the base 69 below the lower housing 12.
The intake manifold is connected through. The throat portion 2 is comprised of an upper throat portion 21 that integrally projects inward from the lower inner surface of the upper housing 11 and a lower throat portion 22 that integrally projects inward from the upper inner surface of the lower housing 12. The annular orifice 4 and the annular expansion chamber 20 surrounding the orifice 4 serve as a gap between the upper housing 11 having a two-part throat portion 21 and the lower housing 12 having a lower throat portion n22. Further, in this gap, there is disposed a 7-neutral ring 25 for controlling the flow rate, which is located between the annular orifice 4 and the expansion chamber 20 located on the outer periphery of the annular orifice 4. Further, the upper throat portion 21 has an inner diameter that becomes smaller as it goes downward, and the lower throat portion 22 has an inner diameter that becomes smaller as it moves upward. The cross-sectional area of the air passage is the smallest in this section.

Next, the fuel path from the float chamber 8 to the orifice 4 will be explained. A total of three fuel paths are provided. The main fuel path is provided in the side wall of the 70-horsepower jumper 8, and its lower end communicates with the 70-horsepower jumper 8 via the fuel hole 16 and the needle valve 17 shown in FIG. The fuel passage 15 is connected to an annular fuel pipe 19 arranged in the expansion chamber 20, and since the fuel pipe 19 is provided with many micro holes, the fuel sent through this fuel passage 15 is Suction (
°・Small groove 2 formed in the annular ring 25 after being taken out
After passing through 6, it reaches orifice 4. Here, a narrow groove 26 is provided in an annular ring 25 that partitions the gap between the upper part housing 11 and the lower housing 12 into the orifice 4 side and the expansion chamber 20 side, and communicates between the two. As shown in FIG. 5, a plurality of rings are formed at equal intervals to cross the lower surface of the 7-neutral ring 25 in an oblique direction that intersects the diameter direction at approximately 60°, and the flow passing through the narrow groove 26 at high speed. i), and a screw 27 for adjusting the flow rate 11i1 protrudes within this narrow groove 26.

Of the other two fuel paths provided as a power fuel system, one is a power fuel supply system 60 provided in the side wall of the broad chamber 8, which responds to the negative pressure value in the intake manifold. The fuel passage 15 is composed of a power piston 61 biased downward by a spring to move up and down, and a valve section including a power valve 62, a valve seat 63, a valve spring 64, etc. driven by the power piston 61. and the inside of the float chamber 8 are communicated through the valve portion and the fuel hole 65.

Note that a needle valve 66 shown in FIG. 7 is provided between the valve portion and the fuel passage 15. It is configured so that the amount of fuel sent to the main fuel path can be further increased. The other power fuel supply system 70 is connected to the accelerator shaft 35 by a linkage 74 and supplies additional fuel to the expansion chamber 20 through a valve 71 that is opened and closed in response to throttle operation, and is shown in FIG. It consists of a 7-well tube 72 whose lower end is inserted into the 70-chamber 8 and the valve 71, and a shet 73 is provided at the opening to the expansion chamber 20. The valve 71 opens when the throttle is fully opened. In addition, 75 in the figure is an air pipe that connects the upper space of the float chamber 8 with the outside. Furthermore, this carburetor is actually equipped with an accelerator pump,
This is not illustrated. - The cone 3 has a pongee 31 that is slidably supported in the axial direction by a support 30 that is press-fitted and attached to the lower end opening of the lower housing 12.
It is fixed to the upper end, has a skirt 32 at the lower part, and the inside of the skirt 32, which has a slight gap with the upper outer peripheral surface of the sabot 30, is used as the negative pressure chamber 7,
The cone 3 is urged upward by a spring 33 provided in the negative pressure chamber 7, and the lower end of the shaft 31 is connected to the accelerator shaft 35 via a link 36 and a link 37. As is clear from FIG. 8, the link 36 is fixed to the accelerator shaft 35, whereas the link 37, which is made up of two members, is freely rotatably attached to the accelerator shaft 35. , a pin 38 provided in the link 36 is slidably engaged with an arcuate elongated hole 39 provided in the link 37. The rotation of the accelerator shaft 35 causes the cone 3 to move up and down to change the pentier area, but the shaft 31 and the cone 3 are connected to the accelerator shaft 35 with some play.
Within this range of play, the cone 3 moves up and down depending on the negative pressure value in the negative pressure chamber 7 communicating with the intake manifold. Note that the range of vertical movement of the cone 3 is further restricted by the stopper 80, etc., so when the maximum rotation angle of the accelerator shaft 35 is α, the maximum rotation of the link 37 corresponding to the maximum vertical movement range of the cone 3 The angle β is larger than the rotation angle α by the play angle between the pin 38 and the elongated hole 39.

The negative pressure chamber 7 is connected to the intake manifold through the gap between the skirt 32 and the support 30 as described above, and at the same time as shown in FIG. The support 30 and 71 are connected to the atmosphere through an air passage 10 formed across the housing 1, and the amount of communication between the negative pressure chamber 7 and the atmosphere through the air passage 10 is controlled by a control valve 9. This is what is meant to be done. This control valve 9 is provided in the upper housing 11, and is connected to the accelerator shaft 35 and the link mechanism 40.
It is connected by , and when you release the accelerator, it opens fully,
When you step on the accelerator, the amount of communication is reduced to ~1.

Next, the air bleed mechanism will be explained. This air bleed mechanism also has a main air bleed mechanism 41 and a second air bleed structure 42. First, the main air bleed mechanism 41 will be explained. As shown in FIGS. After passing through the cleaner 13, the air is heated by heat exchange with the high-temperature exhaust gas of the internal combustion engine, and the air cleaner 13
The air-fuel mixture with room temperature air that has passed through the air cleaner 13 is supplied according to the negative pressure value in the intake manifold, and reaches the expansion chamber 20 from a heat exchange section between the air that has passed through the air cleaner 13 and the high-temperature exhaust gas. an air supply path 44; a vacuum unit 45 connected to the intake manifold;
An air valve 47 is provided in the middle of the air supply path 44 and is connected via a rod 46 to a diaphragm provided as one wall of the negative pressure chamber in the vacuum unit 45, with one end opening on the upper surface of the housing 1. and a second air supply path 48 whose other end is connected to the front stage of the air valve 47 in the air supply path 44 and sends room temperature air after passing through the air cleaner 13 to the air supply path 44;
It is installed in the middle of the second air supply path 4S and consists of a needle valve 49 shown in FIG. When the negative pressure inside the intake manifold is small, the air valve 47 is throttled to limit the amount of air sent into the expansion chamber 20. The air thus sent from the main air bleed mechanism 41 to the expansion chamber 20 mixes with the fuel sucked out from the fuel pipe 19 in the expansion chamber 20 by the negative pressure applied to the venturi, thereby performing air bleed.

The purpose of supplying heated air through heat exchange with high-temperature exhaust gas is to prevent icing, improve the vaporization of the fuel, and ensure good mixing of fuel and air. The reason why heated air and room temperature air can be mixed is that the temperature of the air sent into the expansion chamber 20 can be maintained at a constant temperature of 42 to 45 degrees Celsius. This is because they are doing so. Although the air valve 47 and the control valve 9 are disposed on the same axis, the two operate separately.

As shown in FIG. 4, the second air bleed rock structure 42 includes a piston valve 56 and a valve seat 5 which are biased upward by a spring and move up and down according to the negative pressure value in the intake manifold.
7. It is composed of a valve part consisting of a valve spring 58 and the like, and an air supply passage 59 which has one end open on the upper surface of the housing nog 1 and the other end opened in the middle of the flow path from the expansion chamber 20 to the orifice 4; The air supply path 59 is opened and closed by the valve section according to the negative pressure value in the intake manifold,
Air corresponding to this opening/closing amount is supplied to the front stage of the orifice 4.

As is clear from the above description, this carburetor not only controls the vertical movement of the cone 3 together with the throttle by the negative pressure inside the intake manifold, but also controls the power fuel supply system 60, main air bleed mechanism 41, and second air bleed system. The operation of the rock formation 42 is also controlled, and a thermal valve 5 is provided in the middle of a negative pressure pipe 50 connecting these and the intake manifold (as shown in FIG. 1). This thermal valve 5 opens when the temperature of the cooling water of the internal combustion engine exceeds a predetermined value and communicates the inside of the intake manifold with each of the above-mentioned systems. The second air bleed rock structure 42 does not operate until the internal combustion engine has substantially completed warming up.

However, to explain the operation of the lever carburetor, the fuel passes through the fuel passage 15 under the negative pressure generated by the air flow flowing down the venturi, is mixed with air by air bleed, reaches the orifice 4, and then flows down the venturi. The air is mixed with air and sent to Liangmenisoguan. When the throttle is opened, that is, when the cone 3 is moved downward, the area of the venturi increases and a large amount of air-fuel mixture is supplied. When the negative pressure also increases and the suction force due to this negative pressure becomes greater than the biasing force of the spring 33, the cone 3 also moves downward within a predetermined range independently of the movement of the accelerator pongee 35 to supply a large amount of air-fuel mixture. It is something to do. Since there is an air passage 10 communicating with the atmosphere, the negative pressure value of the negative pressure chamber 7 at this time is determined by the control valve 9.
The value is not the same as that at the intake manifold except when the control valve 9 is shut off, and the control valve 9 is
5 and when the throttle is returned, the control valve 9 is fully opened, and when the throttle is opened, the control valve 9 is conversely throttled. Therefore, the vertical position of the cone 3 depends on the throttle opening and the throttle opening. This is determined by both the controlled negative pressure of the intake manifold. That is, when the engine is idling or when the throttle/torque is returned, the control valve 9 is fully open, and the same amount of air is sucked out from the negative pressure chamber 7 to the intake manifold through the air passage 1.
Since the cone 3 is sent to the negative pressure chamber 7 through 0, the negative pressure chamber 7 does not become a negative pressure, and the cone 3 is at its upper limit position. When the accelerator pedal is depressed and the throttle is opened, the control valve 9 is throttled and the amount of air sent to the negative pressure chamber 7 is smaller than the amount of air sucked out from the negative pressure chamber 7 to the intake manifold. Then, the inside of the negative pressure chamber 7 becomes negative pressure and the cone 3 is sucked downward. As the cone 3 moves downward, the venturi area increases, and as the amount of air flowing down increases, the negative pressure inside the intake manifold decreases, and the amount of air sucked out from the negative pressure chamber 7 to the intake manifold decreases. . Therefore, the cone 3 stops when the amount of air sucked out from the negative pressure chamber 7 becomes equal to the amount of air sent into the negative pressure chamber 7 through the control valve 9. If the accelerator is further depressed from this state, the cone 3 will move further down. When the accelerator pedal is released, the control valve 9 rotates in the opening direction, increasing the amount of air sucked into the negative pressure chamber 7, reducing the negative pressure in the negative pressure chamber 7, and reducing the elastic force of the spring 33. Cone 3
moves upward. Although the cone 3 moves up and down in conjunction with the accelerator shaft 35, it is in a floating state with respect to the accelerator shaft 35, so to speak.
Actual control of the venturi area is determined by the balance between the negative pressure in the intake manifold and the throttle opening. As mentioned above, the reason why the maximum rotation angle of the link 37 corresponding to the downward movement of the cone 3 is β is because if the cone 3 moves up and down at the idle position, the idle rotation speed will not be stable, and when the throttle is fully opened This is because if the cone 3 moves up and down, the operation of the power fuel supply system 70 becomes unstable.

Now, due to the negative pressure generated by the airflow flowing down the venturi whose area is controlled as described above, fuel is sucked out from the orifice 4 surrounding the annular venturi, mixed with air, and sent to the internal combustion engine via the intake manifold. However, the fuel sucked out from this orifice 4 is primarily mixed with air by air bleed as described above. Main air bleed mechanism 4 that mixes air, which is heated by heat exchange with high-temperature exhaust gas and brought to a predetermined temperature by mixing with room-temperature air, with fuel.
1 is activated after the thermal valve 5 is opened when the cooling water of the internal combustion engine exceeds a predetermined temperature. Since the air valve 47 is closed while the cooling water temperature is low, the air bleed air is The air valve 47 is not sent to the expansion chamber 20, but after the cooling water temperature exceeds a predetermined temperature and warming up of the internal combustion engine is almost completed, the air valve 47 is sent to the expansion chamber 20 according to the negative pressure value in the intake manifold. This is to control the amount of air sucked into 20. That is, when the negative pressure inside the intake manifold is large, the rod 46 of the vacuum unit 45 is retracted and the air valve 47 is opened. When the accelerator is depressed and the internal combustion engine becomes high speed, the air valve 47 is throttled because the negative pressure in the intake manifold becomes small. In other words, as the internal combustion engine goes from low speed to high speed, the amount of bleed air decreases and the amount of fuel supplied to orifice 4 increases, and conversely, when the accelerator is released and the internal combustion supply changes from high speed to low speed, At this time, the air valve 47 is opened in response to the negative pressure change in the intake manifold, and the air for the 7th lead increases. The air-bleed fuel passes through the narrow groove 26 of the annular ring 25 at high speed, is sucked out from the orifice 4 to the venturi, and is uniformly mixed with the high-speed air flowing down the venturi.

The second air bleed structure 42 is configured such that when the engine brake is filled, such as when descending from the plane, the negative pressure inside the intake manifold becomes extremely large and the amount of fuel sucked out from the venturi increases, resulting in poor fuel efficiency and exhaust gas. This is provided to prevent the CO and HC inside from becoming too large, and the thermal valve 5 opens:
After that, when the negative pressure in the intake manifold becomes extremely large, the piston valve 56 descends and the air that has passed through the air cleaner 13 is sent to the front chamber of the orifice 4 through the air supply path 59, reducing the negative pressure in the front chamber. In order to make the fuel smaller, the amount of fuel sucked out to the pentieri is reduced, and the fuel is completely combusted. When the negative pressure inside the intake manifold becomes small, the piston valve 56 rises and blocks the air supply path 59.

Inside f18! When the engine rotates at high output and high speed, the power fuel supply system 60, which operates according to the negative pressure value of the intake manifold, operates to supply a rich mixture. In other words, when the throttle is opened by depressing the 7-gas pedal to obtain high output, the negative pressure inside the intake manifold becomes smaller and smaller, and the force to pull up the power piston 61 weakens, so the power piston 61 descends due to the spring bias. Push down the power valve 62. Therefore, the fuel passes through this valve portion and is added to the fuel flowing through the fuel passage 15, thereby creating an air-fuel mixture with a rich mixture ratio. When a higher output is required, the valve 7 connected to the accelerator shaft 35 in the mechanical power fuel supply system 70 can be operated by fully depressing the accelerator and opening the throttle fully.
1 is opened, the fuel in the 70-tower tube 8 not only passes through the above-mentioned flow path, but also flows through the 7-fuel tube 72 and the jet 7.
3 and directly to the expansion chamber 20, and together with the fuel supply from the power fuel supply system 60, a rich air-fuel mixture necessary for high output is created.

Other embodiments are shown in FIGS. 9 to 11. This is because in the embodiment described above, fuel is sucked out from a large number of micro holes provided in the annular fuel pipe 19 disposed in the annular expansion chamber 20 and is guided around the fuel pipe 19 by the main air bleed mechanism 41. However, the main supply system for fuel to the expansion chamber 20 and the main air bleed mechanism 41 are of a commonly used type, The fuel pipe 18 is opened at the upper end in the expansion chamber 20 and extends vertically through the small room 14 to communicate at the lower end with the 70-t chamber 8. The fuel pipe 18 is provided with a large number of micro holes and passes through the air valve 47 in the main air bleed mechanism 41. The air is made to reach inside this small chamber 14 through the pipe 43, and the air is primarily mixed through minute holes in the fuel flowing through the fuel pipe 18 by the negative pressure generated in the pentier. be. The operation is the same as in the previous embodiment.

Further, the embodiment shown in FIG. 12 has the same configuration as the first embodiment, but has a fuel passage 15 and a power fuel supply system 60 and 7.
By forming the 70-tooth jumper 8 equipped with a
This is an example in which setting can be performed horizontally or diagonally. Of course, the embodiments shown in FIGS. 9 to 11 can also be installed in any direction by separating the 70-chambers.

[Effect of the invention 1] As described above, in the present invention, the venturi area is determined by 70-ting the cone and determining the position of the cone in balance with the opening of the negative pressure throttle generated in the intake manifold. It is possible to supply air-fuel mixture with an accurate mixing ratio according to the requirements of 11 of the engines.

[Brief explanation of drawings]

Fig. 1 is a plan view of one embodiment of the present invention, and Fig. 2 is the same A-
0-B sectional view, Figure 3 is the same C-o-D sectional view, and Figure 4 is the same as above.
The figures are A-0-E cross-sectional views of the same as above, and Figures 5 (a), (b), and (c).
) are longitudinal cross-sectional views, bottom views, and enlarged vertical cross-sectional views of the same 7-neutral ring, Figures 6 and 7 are partial cross-sectional views of the same, respectively, and Figures 8 (a) and (b) are the accelerator shafts of the same. 9 is a plan view of another embodiment, and FIG. 10 is the same F-c, -0-H-
111i side view, FIG. 11 is a left side view of the same as above, FIG. 12 is a sectional view of still another embodiment, and No. 13 is a 70-Totian/
<-, in which 1 is the ring, 21 is the throat part, 3 is the cone, 4 is the orifice, 5 is the thermal valve, 7 is the negative pressure chamber, 9 is the control valve, and 35 is the accelerator shaft. show. Agent Patent Attorney Ishi 1) Chief 7 1 Figure 5 (b) (C) Figure 6 Figure 7 U.

Claims (2)

[Claims] (1) Inside the housing, which has a cylindrical air passage that penetrates vertically, a throat part that protrudes into this air passage, and an annular orifice that opens at the inner peripheral edge of the throat part, there is a vertical axis coaxial with the throat part. This carburetor is equipped with a throttle cone that is arranged to be able to reciprocate in the direction of the intake manifold to form an annular variable venturi between it and the throat section, and the cone is driven by suction in accordance with the negative pressure value in the intake manifold. A carburetor comprising a negative pressure chamber and a control valve that controls the amount of communication between the negative pressure chamber and the atmosphere in conjunction with an accelerator. (2) The cone is connected to the accelerator linkage with a predetermined play, and within this play, the cone is driven by the negative pressure value of the negative pressure chamber. Vaporizer as described.