JP3154109B2 - Fuel increase device for multiple carburetor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporizer for controlling the amount and concentration of an air-fuel mixture supplied to an engine.
A plurality of carburetors that mechanically control the opening and closing of the effective opening area of the intake passage penetrating the carburetor body with a throttle valve operated by an accelerator wire, for example, two, three, four, in the horizontal direction, The present invention relates to a fuel increasing device for a multiple carburetor arranged vertically or in a V-shape.

[0002]

2. Description of the Related Art Vaporizers that mechanically control the effective opening area of an intake passage by a throttle valve operated by an accelerator wire are roughly classified into the following two types. First, a valve shaft is rotatably supported by the carburetor body across an intake path penetrating the carburetor body, and a disc-shaped butterfly valve is attached to the valve shaft. A venturi section is formed in the intake passage upstream of the butterfly valve, and a fuel injection hole is formed in the venturi section, which is connected to the float chamber below the constant liquid level. Here, when the driver rotates the valve shaft by operating the accelerator wire, the effective opening area of the intake passage is controlled to be opened and closed by the butterfly valve. (Usually referred to as a butterfly-type vaporizer, a butterfly-type multiple vaporizer using a plurality of the vaporizers is disclosed in, for example, Japanese Utility Model Publication No. 52-57307.)

[0003] Second, a sliding valve guide cylinder is continuously provided laterally from an intermediate portion of an intake passage penetrating the carburetor body, and a cylindrical or short throttle valve is provided in the sliding valve guide cylinder. Is slidably disposed, and a venturi portion is formed by the bottom of the throttle valve and the intake passage, and a fuel injection hole continuous below the constant liquid level of the float chamber is opened in the venturi portion. Here, when the driver operates the accelerator wire to move the throttle valve within the sliding valve guide cylinder, the throttle valve controls opening and closing of the effective opening area of the intake passage (the area of the venturi portion). (Usually, a sliding throttle valve type carburetor is referred to as a sliding throttle valve type carburetor, and a sliding throttle valve type multiple carburetor using a plurality of carburetors is disclosed in, for example, Japanese Utility Model Publication No. 53-38754.) According to the butterfly type multiple carburetor and the sliding throttle valve type multiple carburetor in which the effective opening area of the intake path (the area of the venturi section) is mechanically opened and closed by the throttle valve, the following problems are encountered.

First, in a state where the throttle valve is opened to a high opening and the engine speed is low (high opening low speed operation), the flow velocity of the air flowing through the venturi becomes low, and the fuel opening to the venturi is opened. The venturi negative pressure applied to the orifice is reduced. According to this, it becomes difficult to suck out sufficient fuel from the fuel injection hole into the venturi portion, and this is not preferable because the mixture becomes lean. The mixture leaning phenomenon in the high opening low speed operation becomes more remarkable as the intake passage diameter is increased (the diameter of the venturi portion is increased) in order to improve the output of the engine. As a conventional technique aimed at solving the above, a single carburetor but an air control valve is arranged upstream of the throttle valve, and at the time of high opening low speed operation, the output of the throttle valve opening sensor and A technique for controlling an air control valve in a closing direction based on an output of an engine rotation speed sensor is known. (Shown in Japanese Utility Model Laid-Open No. 60-70761.)

[0005] Second, in the case of a rapid acceleration operation of an engine in which the throttle valve is rapidly opened to a high opening in order to rapidly increase the rotation from a low opening state as in the case of an idling operation of the engine. In consideration of the above, although the increased amount of air is supplied to the engine immediately by the rapid opening of the throttle valve, the supply of fuel is temporarily delayed due to the inertia of the air, resulting in the dilution of the air-fuel mixture. Not preferred. This leaning of the air-fuel mixture becomes more prominent as the diameter of the intake passage is increased (the diameter of the venturi portion is increased). As a conventional technique for solving the above,
The housing is divided into a pump room and an atmosphere room by a diaphragm,
In the pump chamber, an intake-side check valve is arranged inside, and the acceleration fuel inflow passage connected to the float chamber and the discharge-side check valve are arranged inside, and the acceleration is connected to the intake passage of each carburetor. When the throttle valve is suddenly opened, the diaphragm is pressed toward the pump chamber to pressurize the pump chamber, and the accelerating fuel stored in the pump chamber is vaporized through the accelerated fuel discharge path. There is a technology of a so-called acceleration pump device that injects and supplies into an intake passage of a vessel. (Shown in Japanese Utility Model Publication No. 53-32183.)

[0006]

However, the conventional technique has the following disadvantages. First, Showa 60-707
According to the technology of No. 61, at the time of high opening low speed operation, the throttle valve is kept open at a high opening, but the air control valve controls the intake path in the closing direction by an output signal from the control unit to restrict the throttle. This is to reduce the effective opening area of the intake passage upstream of the valve. According to this, the intake path negative pressure in the intake path including the throttle valve on the engine side from the air control valve rises, and the opening of the needle jet as the main fuel system that opens to the venturi section on the engine side from the air control valve The negative pressure of the intake passage applied to the portion is increased, so that a larger amount of fuel can be sucked into the intake passage than the needle jet, thereby preventing the mixture from being lean. However, according to the fact that the air control valve operates the intake passage in the closing direction to reduce the effective opening area of the intake passage, the amount of air supplied to the engine is reduced, which is not preferable in that the output of the engine is improved. . In particular, the use of a multiple carburetor is particularly inconvenient in a multiple carburetor because one of the objects of the purpose thereof is to improve the output of the engine.
Further, the air control valve needs to be arranged in each carburetor, which increases the number of parts and the number of assembling steps, which is not preferable, and further impairs the design freedom of the carburetor as a whole.

Next, the technique of Japanese Utility Model Publication No. 53-32183 is as follows.
The pump chamber is pressurized by the rapid opening operation of the throttle valve, and the accelerating fuel stored in the pump chamber is injected and supplied into the intake passage of each carburetor through the accelerating fuel discharge path. Although it is possible to supply the fuel for acceleration, it is difficult to set the acceleration fuel injection time to be supplied from the acceleration pump device to the intake passage of each carburetor for a long time (to continuously inject the fuel from the initial period to the final period of acceleration). This is due to the fact that the diaphragm for pressurizing the pump chamber of the acceleration pump device is mechanically connected to the throttle valve. Selection of a diaphragm spring that is contracted in the room and urges the diaphragm toward the atmosphere chamber, selection of the diameter of the accelerating fuel suction path and accelerating fuel discharge path, or a suction-side check valve and a discharge-side check valve It takes a lot of time to select a valve-closing spring for pressing and biasing against the seat and the like, and this hinders improvement in development efficiency. Even if each of the above-described elements is selected, there is a limit to extending the acceleration fuel injection time from the initial period to the final period of acceleration since the compression stroke of the diaphragm is uniquely determined by the opening stroke of the throttle valve. It is. In addition, during the acceleration operation from the intermediate opening operation of the throttle valve, the diaphragm is already in a state where the pump chamber is compressed, and it is difficult to further compress the diaphragm. Therefore, sufficient acceleration fuel can be supplied. There was no fear.

In view of the above, a fuel increasing device for a multiple carburetor according to the present invention has been developed in consideration of the above, and has a plurality of carburetors in which a plurality of carburetors for mechanically controlling the effective opening area of the intake passage by a throttle valve are provided. In the carburetor, in the engine, at the time of high opening low speed operation and at the time of acceleration operation, it suppresses the leaning of the air-fuel mixture and actively and precisely removes the air-fuel mixture in various operating regions where the air-fuel mixture becomes lean. It is an object of the present invention to provide a fuel increasing device capable of increasing the fuel density.

[0009]

According to the fuel increasing device for a multiple carburetor according to the present invention, in order to achieve the above object, the effective opening area of the intake passage penetrating the carburetor body is mechanically controlled by a throttle valve. The multiple carburetors with a plurality of carburetors with a venturi section formed in the intake passage and the fuel stored in the fuel tank are pressurized by the fuel head difference or the fuel pump, and each vaporized. A fuel inflow passage for supplying to a valve seat that opens into the float chamber of the vessel, a fuel increasing passage branched from the fuel inflow passage, an output of a rotation sensor arranged in the fuel increasing passage and detecting an engine speed, and a throttle. Opening / closing of the fuel increasing passage is controlled by a control signal from a control circuit to which an output of a pressure sensor for detecting a negative pressure in the intake pipe connected to the engine or the intake pipe connected to the engine (negative pressure in the intake pipe) is input. A control valve for controlling the amount of fuel flowing in the increasing passage; and a fuel increasing distribution passage branched from the fuel increasing passage downstream of the control valve and connected to the intake passage of each carburetor. Control of the amount of fuel within the engine within the range of rotations where the engine speed is determined,
In addition, when the rotational speed is in a constant state within the range of the negative pressure in the intake pipe defined within the range of the rotation, the fuel amount is reduced in accordance with the increase in the negative pressure in the intake pipe and the rotational speed is increased. In the state, the fuel amount is reduced according to the rise of the negative pressure in the intake pipe.

[0010]

When the rotational speed is within a predetermined range of rotation and within a predetermined range of negative pressure in the intake pipe within the above-mentioned range of rotation, the negative pressure in the intake pipe is maintained when the rotational speed is constant. The energization time Ti is shortened in accordance with the rise to increase the fuel
In addition, the amount of fuel supplied from each fuel increase distribution passage 20A, 20B, 20C toward the intake passage 2 of each of the carburetors C1, C2, C3 is reduced. On the other hand, when the vehicle speed is increasing, the negative pressure in the intake pipe is reduced. The energization time Ti is shortened in accordance with the rise of the fuel supply passage 20 and the fuel increase distribution passages 20A, 20B, 20C.
Therefore, the amount of fuel supplied to the intake passage 2 of each of the carburetors C1, C2, C3 is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a fuel increasing device for a multiple carburetor according to the present invention will be described below with reference to the drawings. (Note that this embodiment shows a sliding throttle valve type triple vaporizer, but the vaporizer type may be a butterfly vaporizer, and is not limited to the number of vaporizers. The arrangement is not limited to the vertical arrangement, the V-shaped arrangement, and the like.) First, a single vaporizer C constituting a multiple vaporizer will be described with reference to FIG. 1 is the intake passage 2 inside
Is a carburetor main body in which a sliding valve guide tube 3 is continuously provided upward from a substantially middle portion of the intake passage 2, and a float chamber main body 4 is disposed facing a lower concave portion of the carburetor main body 1. The lower recess and the float chamber main body 4 form a float chamber 5. A valve seat 6 is opened in the float chamber 5, and a float valve 7 for controlling the opening and closing of the valve seat 6 is arranged corresponding to the valve seat 6, and the float valve 7 is a float valve arranged in the float chamber 5. The opening and closing driving force for the valve seat 6 is applied by the movement of the valve seat 8.

A throttle valve 9 for controlling the opening and closing of the effective opening area of the intake passage 2 is movably arranged in the sliding valve guide cylinder 3, and this throttle valve 9 is rotatable with respect to the carburetor body 1. An operating lever 12 is mechanically connected to an operating shaft 10 pivotally supported by a link, a lever, and the like, and an operating lever 12 is integrally attached to a shaft end of the operating shaft that protrudes outside the carburetor body 1. An accelerator wire (not shown), which is operated by a driver, is attached to the operation lever 12. Therefore, when the driver operates the accelerator wire, the operation lever 12 and the operation shaft 10 rotate, and this is transmitted to the throttle valve 9 via a lever, a link or the like, and the throttle valve 9 is moved to the intake passage 2.
Will be opened and closed. Then, a venturi portion 11 is formed by the bottom 9A of the throttle valve 9 opening into the intake passage 2 and the intake passage 2 opposed thereto. The opening area of the venturi section 11 changes with the movement of the throttle valve 9.
(Forms a so-called variable venturi)

A jet needle 13 is integrally attached to the bottom 9A of the throttle valve 9. The jet needle 13 is inserted into a needle jet 14 serving as a fuel injection hole opened in the venturi section 11. Is done. The needle jet 14 is connected to a main fuel jet 16 via a mixing nozzle 15 having an air bleed hole 15A, and an annular acceleration well W is formed around the mixing nozzle 15 described above. This acceleration well W
A liquid surface having substantially the same height as a constant liquid surface formed in the float chamber 5 is formed therein, and a main air passage connected to the atmosphere is opened in the acceleration well W above this liquid surface. (The main air passage is not shown)

On the other hand, a fuel inflow passage 17 is provided in the valve seat 6.
The fuel stored in the fuel tank T described later is supplied in a pressurized state via the fuel tank T. When the fuel tank T is disposed below the carburetor body 1, The fuel is pressurized by a fuel pump P, which will be described later, and supplied to the fuel inflow path 17. On the other hand, when the fuel tank T is disposed above the carburetor main body 1, the fuel in the fuel tank T is displaced by the fuel head. And supplied to the fuel inflow passage 17. The position of the fuel tank T is not limited. Therefore, when the liquid level in the float chamber 5 is lower than the set liquid level, the float valve 7 opens the valve seat 6 by the float 8, and the fuel flows into the float chamber 5 from the fuel inflow path 17 through the valve seat 6. When the liquid level in the float chamber 5 rises to a set constant liquid level, the float valve 7 closes the valve seat 6 with the float 8, and the float valve 7 closes from the fuel inflow passage 17 through the valve seat 6. The supply of fuel to the inside of the float 5 is stopped, so that a constant liquid level can always be formed in the float chamber 5. The above is a conventionally known vaporizer.

In this embodiment, three such vaporizers C are arranged on the side. This state is shown in FIG. 2 and, for convenience, the first carburetor C1, the second carburetor C2,
The vaporizer is C3. For example, an operation shaft 10 is connected so that the throttle valve 9 in each carburetor opens and closes synchronously. The fuel inflow passage 17 of each carburetor is connected to a fuel tank T, and pressurized fuel is supplied into the fuel inflow passage 17.

Reference numeral 20 denotes a fuel increasing passage branched from the fuel inflow passage 17, and a control valve 21 for controlling opening and closing of the fuel increasing passage 20 is disposed in the fuel increasing passage 20. In the control valve 21 according to the present embodiment, the movable iron core 23 is attracted to the fixed iron core 24 by energizing the solenoid 22, and the valve portion 25 formed integrally with the movable iron core 23
A normally closed solenoid valve that opens a valve seat 26 provided in the circulating air conditioner was used. (The control valve 21 is not limited to an electromagnetic valve, but may be appropriately selected as long as it has a function (for example, a motor) for electrically opening and closing the passage.) Then, the fuel increasing passage 20 downstream of the control valve 21 (specifically, Specifically, the fuel increase distribution passages 20A, 20B, and 20C are directed from the fuel increase passage 20) downstream of the valve seat 26 to the intake passages 2 of the carburetors C1, C2, and C3.
Branches. The opening of the fuel increase distribution passages 20A, 20B, 20C to the intake passage 2 is limited within the range of the intake passage 2 or an intake pipe (not shown) that connects the intake passage 2 of the carburetor body 1 to the engine. Not done. In this embodiment, the fuel increase distribution paths 20A, 20B, and 20C are opened with the nozzle N on the upstream side (left side in FIG. 2) of the throttle valve 9.

Reference numeral 27 denotes a rotation sensor for detecting the rotation speed (hereinafter referred to as the rotation speed) of the engine equipped with the carburetor. Reference numeral 28 denotes the intake passage 2 or the engine on the engine side (right side in FIG. 1) from the throttle valve 9. The pressure sensor detects a negative pressure (negative pressure in the intake pipe) in a continuous intake pipe (both not shown). For example, the pressure sensor includes a pressure conversion element and a hybrid IC that amplifies an output signal of the conversion element. For example, the pressure conversion element is a silicon diaphragm type using a piezoresistance effect of a semiconductor, and a vacuum chamber is provided on one side of the silicon diaphragm, and an intake air on the engine side from the throttle valve 9 via the negative pressure introduction path 29 on the other side. A negative pressure in the intake pipe connected to the road 2 or the engine is led. In the present embodiment, the negative pressure introducing passage 29 is provided with a third carburetor C3.
From the throttle valve 9 to the intake passage 2 on the engine side.

The outputs of the rotation sensor 27 and the pressure sensor 28 are input to a control circuit 30 under the conditions of the engine speed and the negative pressure in the intake passage on the engine side from the throttle valve 9 or in the intake pipe connected to the engine. A control signal for driving the control valve 21 is output from the control circuit 30. An example of the conditions under which the control circuit 30 outputs a control signal for driving the control valve 21 from the control circuit 30 and the conditions under which the negative pressure in the intake pipe is determined is as follows.
A control signal for driving the control valve 21 is output from the control circuit 30 to the control valve 21 within the range of M and within the range of the negative pressure in the intake pipe which is within the range of the predetermined rotational speed. . More specifically, the rotation speed is 3000RP
In M, negative pressure in the intake pipe is -200m from -3mmHg
mHg, the negative pressure of the intake passage is -3 mmHg to -12 mmHg at a rotation speed of 6000 RPM, and -3 mmHg to -9 mmHg at a rotation speed of 8000 RPM. The condition range is clearly shown in the outline of FIG. 3, but this condition range is appropriately set at the time of setting the carburetor for the engine and is not limited to the above condition.

A special feature here is that the control circuit 30
A control signal output from the control valve 21 to the control valve 21 is a drive pulse having a conduction time Ti, and the number of rotations is within a predetermined range of rotation, and within a predetermined range of rotation, the predetermined negative pressure in the intake pipe. Within the range, when the rotational speed is constant, the energization time Ti is shortened in accordance with the rise of the negative pressure in the intake pipe to increase the fuel increasing passage 20 and the fuel increasing distribution passages 20A and 20A.
B, 20C, the amount of fuel supplied to the intake passage 2 of each of the carburetors C1, C2, C3 is reduced. On the other hand, when the vehicle speed is increasing, the energizing time Ti is increased according to the increase in the negative pressure in the intake pipe.
And the fuel increase passage 20 and each fuel increase distribution passage 20
It is preferable to reduce the amount of fuel supplied from A, 20B, and 20C to the intake passage 2 of each of the carburetors C1, C2, and C3. This state is clearly shown in FIG. 4. In FIG. 4, the mesh area has the largest amount of fuel supplied from the control valve 21, and the solid line (referred to as a large flow rate) has the largest amount of fuel in the hatched area next to the mesh area ( Further, the amount of fuel in the hatched area indicated by the dotted line is larger than that in the hatched area indicated by the solid line. According to the above (referred to as a small flow rate), for example,
In a constant rotation state of 000 RPM, a large amount of fuel increase correction is performed in the range of the negative pressure in the intake pipe from -3 mmHg to -10 mmHg, and the negative pressure in the intake pipe is reduced to -10 mmHg.
Medium flow rate fuel increase correction is performed in the range of Hg to −30 mmHg, and small flow rate fuel increase correction is performed in the intake pipe negative pressure range of −30 mmHg to −200 mmHg.

Next, the operation will be described. First, a low opening operation state in which the opening of the throttle valve 9 is relatively low (for example, 3/8 opening or less) will be described. As a result, the flow velocity of the air flowing through the venturi portion 11 of the small opening is increased, and
1 and the intake passage 2 downstream of the venturi section 11 are maintained at an increased pressure, so that the needle jet 14 as the main fuel system and the bypass hole and the pilot outlet hole as the low-speed fuel system (not shown) form the venturi section 1.
1 and the appropriate fuel is sucked into the intake passage 2 and supplied to the engine from each of the carburetors C1, C2, C3, and the operation of the engine is maintained at a relatively low speed in accordance with the low opening degree of the throttle valve 9, A desired low-speed operation can be performed. According to this, since the rotation speed is less than 3000 RPM and out of the predetermined rotation speed range, the output from the rotation sensor 27 to the control circuit 30 is not made, and the control circuit 30
No control signal for driving is output. Accordingly, the control valve 21 is in the inoperative state, and the valve portion 25 of the control valve 21 closes and holds the valve seat 26. The fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, and 20C cause the respective carburetors C to pass through.
No increased fuel is supplied to the intake passage 2 of C1, C2 and C3.

Next, the throttle valve 9 is further opened from the low opening operation state (the opening degree of the throttle valve 9 is not more than 3/8 opening degree), while the throttle valve 9 is in the high opening operation state (the opening degree of the throttle valve 9 becomes lower). An operation state in which the load is applied to the engine with a small load or a medium load will be described.
In such an operating state, the throttle valve 9 is opened to a medium or high opening, and the load applied to the engine is not relatively large, so that the engine speed appropriately increases in proportion to the opening of the throttle valve 9. According to this, the flow velocity of the air flowing through the venturi section 11 is increased, and the negative pressure of the venturi section 11 is sufficiently increased, and appropriate fuel corresponding to the negative pressure is sucked into the intake passage 2 from the needle jet 14. More specifically, referring to FIG. 2, when the rotation speed is 3000 RPM, the negative pressure in the intake pipe exceeds -200 mmHg and the rotation speed is 600
At 0 RPM, the negative pressure in the intake pipe exceeds -12 mmHg, and at 8000 RPM, the negative pressure in the intake pipe is-
Exceeds 9 mmHg. That is, in such an operation state, the negative pressure in the intake pipe with respect to the rotation speed shown in FIG. 3 rises to a negative pressure outside the outline range. Therefore, the control signal for driving is not output from the control circuit 30 to the control valve 21 because the pressure sensor 28 does not output the control signal to the control circuit 30, and the control valve 21 closes and holds the fuel increasing passage 20. It is. As described above, when the throttle valve 9 is in the high opening operation and the load applied to the engine is small and in the middle load operation, the fuel increasing passage 20 and each fuel increasing distribution passage 2 are operated.
Although the amount of fuel is not increased from 0A, 20B, and 20C, as described above, the negative pressure in the venturi section 11 is sufficiently increased, so that the needle jet 14 as the main fuel system is not used.
More appropriate fuel is sucked into the venturi section 11 and supplied to the engine from each of the carburetors C1, C2, C3 to satisfy the operation of the engine.
High speed operation can be obtained.

On the other hand, although the throttle valve 9 is opened to a medium or high opening degree (for example, the opening degree of the throttle valve 9 is opened by 3/8 or more), the vehicle speed varies according to the opening degree of the throttle valve 9. This is the case where it does not rise sufficiently. Such a state is a state in which the throttle valve 9 is opened to a high degree at the middle and a high load is applied to the engine. For example, this state corresponds to a state in which a steep hill is climbed or a load is fully loaded. In this state, the throttle valve 9 is
The engine is opened to a high degree of opening. On the other hand, the rotational speed of the engine decreases due to the application of a high load, the flow velocity of the air flowing through the venturi section 11 decreases, and the negative pressure of the venturi section 11 decreases. That is, the amount of fuel sucked into the intake passage 2 from the needle jet 14 decreases, and the air-fuel mixture in each of the carburetors C1, C2, and C3 is diluted, and the increase in engine speed is hindered. As a result, an appropriate vehicle speed for the throttle valve opening cannot be obtained. In other words, it is not possible to obtain an appropriate vehicle speed with respect to the throttle valve opening degree, in other words, it is not possible to obtain an appropriate rotation speed with respect to the throttle valve opening degree. This leads to a failure to obtain negative pressure in the intake pipe. Referring to FIG. 3, the negative pressure in the intake pipe is-when the rotational speed is 3000 RPM.
When the rotation speed is 6000 RPM, the negative pressure in the intake pipe is -12 mmHg or less, and when the rotation speed is 8000 RPM, the negative pressure in the intake pipe is -9 mmHg.
g or less. When such a state is reached, the rotation speed is detected by the rotation sensor 27 and its output is input to the control circuit 30, while the negative pressure in the intake pipe is detected by the pressure sensor 28 and its output is input to the control circuit 30. You.

When the outputs from the rotation sensor 27 and the pressure sensor 28 are input to the control circuit 30, the control circuit 30 outputs a control signal for driving the control valve 21 to the control valve 21. The control valve 21 receives the control signal, and the valve portion 25 opens the valve seat 26 by the movable iron core 23 being attracted to the fixed iron core 24. According to this, a part of the pressurized fuel supplied into the fuel inflow passage 17 is divided from the fuel inflow passage 17, and the carburetors C1, C2, and C2 are supplied from the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, and 20C. The throttle valve 9 is immediately and injected into the intake passage 2 of C3. The throttle valve 9 is opened to a middle and high opening degree together with the fuel sucked into the venturi portion 11 from the needle jet 14 as the main fuel system. In addition, the lean speed of the air-fuel mixture during high load operation is suppressed to increase the engine speed, and the increase in the engine speed increases the vehicle speed to an appropriate vehicle speed according to the throttle valve opening. The fuel increase passage 20 and the fuel increase distribution passages 20A, 20A
B, 20C, the supply of the increased fuel into the intake passage 2 of each of the carburetors C1, C2, C3 is within a predetermined rotational speed range and a predetermined intake pipe negative pressure range (in other words, a throttle valve The rotation speed (vehicle speed) is not increased to an appropriate value for the opening degree). In FIG. 3, if an example is explained, the rotation speed is -3 at 3000 RPM.
mmHg to -200 mmHg, and at a rotation speed of -6000 RPM, -3 mmHg to -1.
Within 2mmHg, and rotation speed is 8000RP
M is in the range of -3 mmHg to -9 mmHg. When the rotation speed rises and falls outside the predetermined rotation speed range, or when the rotation speed falls within the predetermined rotation speed range and falls outside the predetermined negative pressure range of the intake pipe, In other words, if either one or both of the conditions are satisfied, ie, the rotation speed (vehicle speed) appropriate to the throttle valve opening degree is reached, the control from the control circuit 30 for driving the control valve 21 is performed. The output of the signal is stopped, the control valve 21 returns to the original position, and the valve 25
Is closed, whereby the carburetors C1, C are connected from the fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, 20C.
2, to stop supplying fuel to the intake path 2 of C3. In FIG. 3, if an example is explained, the number of rotations is 900
When the rotational speed exceeds 0 RPM, the rotational speed falls out of the negative pressure range in the intake pipe from −3 mmHg to −200 mmHg at 3000 RPM, and the rotational speed decreases by −3 at 6000 RPM.
When the rotation speed is out of the negative pressure range in the intake pipe from mmHg to -12 mmHg, the rotation speed is -3 mmHg at 8000 RPM.
-9 mmHg from the negative pressure range in the intake pipe.

The throttle valve 9 is in an acceleration operation in which the throttle valve 9 is rapidly opened from a low opening to a medium or high opening. The throttle valve 9 is in a low opening state, the rotation speed is low, and the vehicle speed is 50 km / km. It is in a low speed condition that cannot be reached sometimes. In this state, the driver pulls the accelerator wire to quickly open the throttle valve 9 to the middle and high opening state to perform the acceleration operation. Here, the behavior of fuel supply to the intake passage 2 when the throttle valve 9 is rapidly opened from the low opening state to the middle and high opening states is as follows. When the throttle valve 9 is in the low opening state, the engine speed is idling rotation (for example, 1200 RPM) or 3000 RP.
The vehicle speed is low at a low rotation of M or less. In this state, the fuel is mainly supplied from the low speed fuel system (not shown) such as the bypass hole and the pilot outlet hole to the intake passage 2.
The engine is sucked into the engine to perform low-speed low-speed operation of the engine. Next, when the throttle valve 9 is rapidly opened to a medium or high opening degree from the low opening state of the throttle valve 9, the amount of air flowing through the intake passage 2 is increased at a stretch. Road 2
The negative pressure at the tip of the needle jet 14 opening into the inside temporarily rises slightly. According to this, the fuel stored in the acceleration well W is sucked into the venturi section 11 from the needle jet 14 via the mixing nozzle 15 to increase the engine speed. In this state, the fuel in the accelerating well W is sucked into the venturi section 11 through the needle jet 14 because the negative pressure of the intake passage applied to the opening of the needle jet 14 temporarily increases slightly, This is because there is no restriction on the inflow by the fuel jet 16 and the fuel is already stored in the acceleration well W downstream of the main fuel jet 16 and is easily sucked out. However, acceleration well W
Since the fuel stored in the accelerating well W is also limited by the suction of the fuel inside, the engine speed is greatly increased and the vehicle speed is not greatly increased. That is, even if the throttle valve 9 is opened to a medium or high opening, it is difficult to immediately increase the rotation speed, that is, the vehicle speed according to the throttle valve opening. If the capacity in the acceleration well W is increased, it is possible to increase the rotation speed during acceleration and increase the vehicle speed. However, the inner and outer diameters of the mixing nozzle 15 are determined in consideration of the operability in other operation regions. This is because the capacity of the acceleration well W is inevitably limited because it is determined. In such a state, in the present invention, the throttle valve 9 is opened to a medium opening and a high opening from a low opening, and the rotation is slightly increased by the fuel in the acceleration well W. Within the range (not that the engine speed (vehicle speed) has risen appropriately in accordance with the throttle valve opening) and that the engine speed has not sufficiently increased in the above-mentioned rotational state and the intake pipe has been set The output of the rotation sensor 27 and the pressure sensor 28 for detecting the negative pressure is not included in the range of the negative pressure (it does not mean that the negative pressure in the intake pipe is appropriately increased in accordance with the opening degree of the throttle valve). Then, a control signal for driving is output from the control circuit 30 to the control valve 21. According to this, since the valve portion 25 of the control valve 21 immediately opens the valve seat 26, the fuel pressurized from the fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, 20C is supplied to the carburetors C1, C2, C3 is injected into the intake passage 2 to suppress leaning of the air-fuel mixture during the acceleration operation, and to effectively increase the rotation during the acceleration operation. It can accelerate to rotation (vehicle speed). Then, receiving the supply of fuel from the fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, and 20C, the engine speed sufficiently increases, and the vehicle speed appropriately increases according to the throttle valve opening. When the negative pressure in the intake pipe at the rotation speed is sufficiently increased, the output of the control signal from the control circuit 30 to the control valve 21 is stopped, and the fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, 20
The supply of fuel from C to each of the carburetors C1, C2, and C3 is interrupted. However, since the engine speed is appropriately increasing according to the throttle valve opening, the needle as the main fuel system is Since a large negative pressure acts on the jet 14, fuel suitable for high-opening operation in the throttle valve 9 can be drawn into the intake passage 2 from the needle jet 14. The above-described acceleration operation will be described with reference to a specific example with reference to FIG. 3. When the throttle valve 9 is at a low opening of 2/8 and the rotation speed is 2000 RPM, the throttle valve 9 is rapidly opened at a 4/8 opening. , When the rotation speed is 4000 RPM and the negative pressure in the intake pipe is -8 mmHg, the throttle valve 9
The rotation sensor 27 and the pressure sensor 28 detect this state, and the outputs of the sensors 27 and 28 are input to the control circuit 30. A signal for driving the control valve 21 is output from the control circuit 30. According to this, the fuel increase passage 20 and each fuel increase distribution passage 20A, 20B,
Fuel is immediately supplied from 20C to the intake passages 2 of the carburetors C1, C2, and C3, the mixture is prevented from being lean, the engine speed is increased, and the vehicle is accelerated to a vehicle speed corresponding to the throttle valve opening. Can rise. When the rotation speed rises to 5000 RPM according to the throttle valve opening due to the increase in the rotation and the negative pressure in the intake pipe rises above -17 mmHg (the throttle valve 9 is held at a 4/8 opening and the rotation is reduced). The output from the pressure sensor 28 to the control circuit 30 is stopped (the rotation speed is 5000).
In the case of RPM, the pressure sensor 28 outputs to the control circuit 30 within the range of the negative pressure in the intake pipe of -3 mmHg to -17 mmHg), whereby the output from the control circuit 30 to the control valve 21 stops, and the fuel increasing passage 20 and The supply of fuel to the intake path 2 of each of the carburetors C1, C2, C3 from the respective fuel increase distribution paths 20A, 20B, 20C is stopped.

Further, even during an intermediate acceleration operation in which the throttle valve 9 is rapidly opened from an intermediate opening degree, for example, 4/8 opening degree to 6/8 opening degree, the negative pressure of the venturi portion 11 does not increase immediately.
In some cases, the increase in the number of revolutions is suppressed and the vehicle speed does not increase to the desired speed. In such a state, the control valve 21 performs the above operation by the signal output from the control circuit 30 to improve the intermediate acceleration operation. Can be planned. FIG.
A more specific example will be described.
8. Revolution speed 5000 RPM, negative pressure in intake pipe -30mm
Assuming that the throttle valve 9 is rapidly opened to a high opening of 6/8 from the Hg throttle valve intermediate opening operation, the rotation speed becomes 6000 RPM, and the negative pressure in the intake pipe becomes -5 mmHg (throttle valve 9
The vehicle speed sensor 27 and the pressure sensor 28 detect this state, and the outputs of the sensors 27 and 28 are input to the control circuit 30. A signal for driving the control valve 21 is output from the control circuit 30. According to this, the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 20
Fuel is immediately supplied from C to the intake path 2 of each of the carburetors C1, C2, and C3, the mixture is prevented from being diluted, the engine speed is increased, and the vehicle speed is adjusted to the throttle valve opening degree. Can accelerate and rise. When the rotation speed increases to 7000 RPM according to the throttle valve opening due to the increase in the rotation and the negative pressure in the intake pipe exceeds -10 mmHg (the throttle valve 9 is set to 6
/ 8 opening is maintained, and the negative pressure in the intake pipe increases due to the increase in rotation.)
From the control circuit 30 to the control valve 21 by stopping the output toward the control circuit 30 (at a rotation speed of 7000 RPM, the pressure sensor 28 outputs to the control circuit 30 within the range of the negative pressure in the intake pipe of -3 mmHg to -10 mmHg). The output is stopped, and the carburetors C1, C are supplied from the fuel increasing passage 20 and the fuel increasing distribution passages 20A, 20B, 20C.
2. The supply of fuel to the intake path 2 of C3 is stopped.

The above is an outline of the operation of the present invention. In the present invention, in particular, the control signal output from the control circuit 30 to the control valve 21 is used as a drive pulse for the energization time Ti, and the rotational speed is determined. Within the range of rotation, and within the range of the negative pressure in the intake pipe determined within the range of rotation, if the rotational speed is in a constant state, the energization time Ti is shortened in accordance with the rise in the negative pressure in the intake pipe. The fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 20C are used to separate the carburetors C1, C
2, while the amount of fuel supplied to the intake passage 2 of C3 is reduced, while the vehicle speed is increasing, the energization time Ti is shortened in accordance with the increase of the negative pressure in the intake pipe, and the fuel increasing passage 20 and It is preferable to reduce the amount of fuel supplied from each of the fuel increase distribution paths 20A, 20B, and 20C toward the intake passage 2 of each of the carburetors C1, C2, and C3. This state is clearly shown in FIG. 3. In FIG. 3, the mesh amount is the largest in the amount of fuel supplied from the control valve 21, and the solid line (called a large flow rate) has the largest amount of fuel in the hatched area next to the mesh area ( Further, the amount of fuel in the hatched area indicated by the dotted line is larger than that in the hatched area indicated by the solid line. According to the above (referred to as a small flow rate), for example, in a constant rotation state where the rotation speed is 3000 RPM, the negative pressure in the intake pipe is from -3 mmHg to -10 mmHg.
The fuel increase correction of the large flow rate is performed in the range of, the fuel increase correction of the medium flow rate is performed in the range of −10 mmHg to −30 mmHg of the negative pressure in the intake pipe, and the fuel increase correction is small in the range of −30 mmHg to −200 mmHg of the negative pressure in the intake pipe. Fuel increase correction of the flow rate is performed. According to this, a large amount of fuel increase correction is performed as it becomes difficult to suck the fuel from the venturi section 11 into the intake passage 2 due to a decrease in the negative pressure in the intake pipe (the negative pressure decreases). The supplied air-fuel mixture is properly controlled, which has a great effect in terms of engine operability, emission of harmful exhaust gas, and fuel economy. Such an operating state occurs when the load applied to the engine changes at a constant vehicle speed (at a constant rotational speed). As the load increases, the negative pressure in the intake pipe decreases, and as the load decreases, the negative pressure in the intake pipe decreases. The negative pressure in the intake pipe increases. Thus, as the load increases, the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 20C
Thus, the amount of fuel supplied to each of the carburetors C1, C2, C3 can be increased, and it is possible to appropriately cope with high-load operation. (In other words, as the load becomes smaller, the amount of fuel supplied from the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, and 20C can be reduced, so that low-load operation can be appropriately handled.)

Further, it is possible to further improve the accelerated driving performance of the engine. For example, considering acceleration operation of an engine in which the throttle valve 9 is rapidly opened to a medium opening and a high opening from a low opening, as described above, the throttle valve 9 is at a low opening and the rotational speed is 2.
From the state of 000 RPM, the throttle valve 9 is rapidly opened to an intermediate opening of 4/8, and when the rotational speed becomes 4000 RPM and the negative pressure in the intake pipe becomes -8 mmHg, the control circuit 30 drives the control valve 21. Are output, and according to this, the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 2
0C, fuel is supplied to the intake passage 2 of each of the carburetors C1, C2, C3, and the number of revolutions is 5000 RPM according to the throttle valve opening.
When the negative pressure in the intake pipe exceeds -17 mmHg, the fuel increasing passage 20 and each fuel increasing distribution passage 20 are accelerated.
The supply of fuel from A, 20B, 20C to the intake passage 2 of each of the carburetors C1, C2, C3 is stopped. This rotation speed 4
When the rotation is increased from 000 RPM to 5000 RPM, the negative pressure in the intake pipe is changed from -8 mmHg to -17 mmHg.
From -8 mmHg to -17
When the negative pressure in the intake pipe rises up to mmHg, the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 20C
Is supplied into the intake passage 2 of each of the carburetors C1, C2, and C3 from the beginning, a medium flow rate of fuel is supplied,
It can be automatically reduced to a small flow rate as the rotational speed and the negative pressure in the intake pipe increase. Thus, as the acceleration proceeds, the fuel increase passage 20 and the fuel increase distribution passages 20A, 20B, 20C
It is preferable to reduce the supply of fuel from the needle jet because the negative pressure in the intake passage increases with the progress of acceleration and the suction of fuel from the needle jet 14 increases. As described above, an appropriate fuel correction can be performed for the acceleration operation of the engine, so that the acceleration operability can be further improved.

Also, a large flow rate within the mesh range described above,
When the control valve 21 is controlled by arbitrarily changing the energizing time Ti in each of the medium flow rate in the hatched area indicated by the solid line and the small flow rate in the hatched area indicated by the dotted line, the fuel increasing passage 20 and the fuel increasing distribution paths 20A and 20B are controlled. , 20C
The control of the fuel supplied into the intake passage 2 of each of the carburetors C1, C2, C3 can be more accurately and finely controlled.
Alternatively, the control valve 21 may be a linear solenoid valve in which the valve portion 25 moves linearly with respect to the valve seat 26 so that the opening area thereof can be varied steplessly.

[0029]

As described above, the fuel increase device for a multiple carburetor according to the present invention has the following effects. The control of the fuel amount in the fuel increasing passage by the control valve is performed in a state where the rotational speed is constant within the range of the predetermined rotational speed and within the range of the negative pressure in the intake pipe within the range of the rotational speed. According to the fact that the fuel amount was reduced in accordance with the increase in the intake pipe negative pressure and the fuel amount was reduced in accordance with the increase in the intake pipe negative pressure when the engine speed was increasing,
In the throttle valve, at the time of high opening operation, it is possible to suppress the leaning of the air-fuel mixture by supplying the fuel pressurized from the fuel increasing passage positively without depending on the negative pressure of the venturi portion at the same time. The mixture can be prevented from becoming lean during acceleration operation, and the fuel control characteristics of the multiple carburetor can be precisely matched to the engine's requirements within a very short time. And achieved a significant improvement in development efficiency.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a single vaporizer which is a vaporizer constituting a multiple vaporizer and has no acceleration pump device.

FIG. 2 is an overall system diagram including a longitudinal sectional view showing a first embodiment of a fuel increasing device for a multiple carburetor according to the present invention in which a plurality of carburetors shown in FIG. 1 are arranged.

FIG. 3 is a diagram showing an example of a range in which an output for driving is output from a control circuit to a control valve in a relationship between an engine speed and an intake pipe negative pressure.

[Explanation of symbols]

 Reference Signs List 2 intake path 5 float chamber 6 valve seat 9 throttle valve 11 venturi section 14 needle jet 17 fuel inflow path 20 fuel increase path 20A, 20B, 20C fuel increase distribution path 21 control valve 27 rotation sensor 28 pressure sensor 30 control circuit 31 pressure regulator T Fuel tank P Fuel pump J Control jet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-151553 (JP, A) JP-A-3-151554 (JP, A) JP-A-61-229964 (JP, A) JP-A-59-159 155557 (JP, A) JP-A-57-198343 (JP, A) JP-A-51-116327 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 7/12 F02D 41 / 10 325 F02M 9/06 F02M 13/02

Claims (1)

(57) [Claims] 1. A multiple carburetor in which an effective opening area of an intake passage penetrating a carburetor body is mechanically controlled by a throttle valve to open and close, and a plurality of carburetors having a venturi formed in the intake passage are provided. The fuel stored in the fuel tank is pressurized by a fuel head difference or a fuel pump and supplied to valve seats opened in the float chambers of the respective carburetors, and a fuel increase branched from the fuel inflow passage. An output of a rotation sensor that is disposed in the passage and the fuel increasing passage and that detects the number of revolutions of the engine, and a pressure that detects a negative pressure in the intake pipe connected to the engine from the throttle valve or in the intake pipe connected to the engine (negative pressure in the intake pipe). A control valve for controlling the amount of fuel flowing through the fuel increasing passage while controlling the opening and closing of the fuel increasing passage by a control signal from a control circuit to which the output of the sensor is input, and a control valve for controlling the amount of fuel flowing through the fuel increasing passage from the fuel increasing passage downstream of the control valve. The control valve controls the amount of fuel in the fuel increase passage within the range of rotations in which the engine speed is determined, and the control valve controls the fuel amount in the fuel increase passage. Within the range of rotation and within the range of the determined negative pressure in the intake pipe, if the rotational speed is in a constant state, the fuel amount is reduced in accordance with the increase in the negative pressure in the intake pipe and the rotational speed is increased. A fuel supply system for a multiple carburetor, characterized in that the fuel amount is reduced in accordance with an increase in the negative pressure in the intake pipe.