JPH05256198A - Fuel quantity increasing device for carburetor - Google Patents

Abstract

PURPOSE:To inhibit mixture from becoming lean in an engine, during high-opening low-speed operation and during accelerating operation and positively make the mixture rich in a specific operating region where the mixture becomes lean, in a fuel quantity increasing device for a carburetor. CONSTITUTION:A fuel quantity increasing device for a carburetor is formed of a carburetor 1 provided with a throttle valve 9 for mechanically controlling the opening/ closing of the effective opening area of an intake passage 2, and a venturi part 11; a fuel inflow passage 17 for applying pressure to the fuel in a fuel tank T by a fuel pump P or the like so as to feed the fuel to a float chamber 5; a fuel quantity increase passage 20 with one end thereof connected to the fuel inflow passage 17 and with the other end thereof connected to the intake passage 2; and a control valve 21 for controlling the opening/closing of the fuel quantity increase passage 20 by a control signal from a control circuit 30 receiving the output of a throttle valve opening sensor 27 and a vehicle speed sensor 28. When the opening of the throttle valve 9 is the fixed value or more and the vehicle speed is within a range of the fixed vehicle speed determined in relation to the opening of the throttle valve 9, the control valve 21 is put in action by the control signal from the control circuit 30 to open the fuel quantity increase passage 20.

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 air-fuel mixture supplied to an engine.
The present invention relates to a fuel amount increasing device for a carburetor, which mechanically controls opening / closing of an effective opening area of an intake passage passing through a carburetor main body by a throttle valve operated by an accelerator wire.

[0002]

2. Description of the Related Art There are the following two types of carburetors which mechanically control the opening / closing of an effective opening area of an intake passage by a throttle valve operated by an accelerator wire. Firstly, a valve shaft is rotatably supported by the carburetor main body across an intake passage passing through the carburetor main body, and a disc-shaped butterfly valve is attached to the valve shaft. A venturi portion is formed in the intake passage upstream of the butterfly valve, and a fuel injection hole is formed in the venturi portion. The fuel injection hole opens below the constant liquid surface of the float chamber. Here, when the driver operates the accelerator wire to rotate the valve shaft, the butterfly valve controls the opening and closing of the effective opening area of the intake passage. (Usually referred to as a butterfly type vaporizer, and is shown in, for example, Japanese Utility Model Publication No. 50-43617.)

Secondly, a sliding valve guide cylinder is provided continuously from the middle part of the intake passage penetrating the carburetor main body to the side, and a cylindrical or rectangular throttle valve is provided in the sliding valve guide cylinder. The venturi portion is formed by the bottom of the throttle valve and the intake passage, and a fuel injection hole is formed in the venturi portion. Here, when the driver operates the throttle wire to move the throttle valve in the sliding valve guide cylinder, the throttle valve controls the opening / closing of the effective opening area of the intake passage (the area of the venturi portion). (Usually called a sliding throttle valve type carburetor, which is shown in, for example, Japanese Utility Model Publication No. 52-54671.)

The above-mentioned butterfly type vaporizer and sliding throttle valve type vaporizer in which the effective opening area (area of the venturi portion) of the intake passage is mechanically controlled by the throttle valve to have the following problems. First, the throttle valve is opened to a high opening,
When the vehicle speed is low (high opening low speed operation), the flow velocity of the air flowing through the venturi portion is low, and the venturi negative pressure applied to the fuel injection hole opening in the venturi portion is weakened. According to this (close to the atmospheric pressure), it becomes difficult to suck sufficient fuel from the fuel injection hole to the venturi portion, which causes a lean mixture, which is not preferable. The phenomenon of leaning of the air-fuel mixture in the high opening and low speed operation becomes more remarkable as the diameter of the intake passage is increased (the diameter of the venturi portion is increased) in order to improve the output of the engine. As a conventional technique aiming to solve the above, an air control valve is arranged on the upstream side of the throttle valve, and the air is controlled by the output of the throttle valve opening sensor and the output of the engine speed sensor during high opening and low speed operation. A technique for controlling the control valve in the closing direction is known. (Shown in Jitsukai Sho 60-70761.)

Secondly, when the throttle valve is suddenly accelerated to a high opening degree in order to rapidly increase the rotation speed from a low opening state, as in the idling operation of the engine, during a rapid acceleration operation of the engine. As a result, the engine is immediately supplied with the increased amount of air by the sudden opening of the throttle valve, but the fuel supply is temporarily delayed by the air inertia, resulting in the lean mixture. Not preferred. This leaning phenomenon 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 aiming to solve the above,
The diaphragm is used to divide the housing into a pump room and an atmosphere room.
In the pump chamber, an intake side check valve is arranged inside, and an acceleration fuel inflow path connected to the float chamber, and a discharge side check valve is arranged inside, and an acceleration fuel discharge path connected to the intake passage. The diaphragm is opened, and this diaphragm is pushed toward the pump chamber side during the sudden opening operation of the throttle valve to pressurize the pump chamber, and the acceleration fuel stored in the pump chamber is injected and supplied into the intake passage through the acceleration fuel discharge passage. There is a so-called acceleration pump device technology. (Shown in Japanese Examined Patent Publication No. 46-43050.)

[0006]

According to such a conventional technique, there are the following inconveniences. First of all, Shokai Sho 60-70
According to the technology of No. 761, during high speed low speed operation,
Although the throttle valve is kept open at a high opening, the air control valve controls the intake passage in the closing direction by the output signal from the control unit to reduce the effective opening area of the intake passage upstream of the throttle valve. Is. According to this, the intake passage negative pressure in the intake passage including the throttle valve on the engine side of the air control valve rises, and the opening of the needle jet as the main fuel system opening to the venturi section on the engine side from the air control valve. The intake passage negative pressure applied to the portion is increased, so that a larger amount of fuel than the needle jet can be sucked out into the intake passage, and thus leaning of the air-fuel mixture can be prevented. However, since the air control valve operates to close the intake passage and reduces the effective opening area of the intake passage, the amount of air supplied to the engine is reduced, which is not preferable in improving the output of the engine. ..

The technology of Japanese Patent Publication No. 46-43050 is as follows.
The pump chamber is pressurized by the sudden opening action of the throttle valve, and the acceleration fuel stored in the pump chamber is injected and supplied into the intake passage through the acceleration fuel discharge passage. However, it is difficult to set the acceleration fuel injection time to be supplied from the acceleration pump device into the intake passage to be long (injecting continuously from the initial stage to the final stage of acceleration). This is because the diaphragm that pressurizes the pump chamber of the acceleration pump device is mechanically connected to the throttle valve.To increase the acceleration fuel injection time, select the chamber volume of the pump chamber, Select a diaphragm spring that is compressed in the room to urge the diaphragm toward the atmosphere chamber, select the passage diameter of the acceleration fuel intake passage and the acceleration fuel discharge passage, or check the intake side check valve and the discharge side check valve. It takes a lot of time to select a valve closing spring for biasing against the seat, which hinders improvement in development efficiency. Even if the above-mentioned elements are selected, the compression stroke of the diaphragm is uniquely determined by the opening stroke of the throttle valve, so there is a limit to the extension of the acceleration fuel injection time from the initial stage to the final stage of acceleration. Is. Further, during the acceleration operation from the intermediate opening operation of the throttle valve, the diaphragm has already compressed the pump chamber and it is difficult to further compress the diaphragm, so that sufficient fuel for acceleration cannot be supplied. I was afraid.

The fuel amount increasing device for a carburetor according to the present invention has been made in view of the above, and in a carburetor in which the effective opening area of the intake passage is mechanically controlled to be opened / closed by a throttle valve, the middle, high opening of the engine is performed. It is an object of the present invention to provide a fuel amount increasing device capable of suppressing leaning of the air-fuel mixture during low-speed low-speed operation and acceleration operation and positively thickening the air-fuel mixture in a specific operation region where the air-fuel mixture becomes lean. It is a thing.

[0009]

According to the fuel amount increasing device for a carburetor according to the present invention, in order to achieve the above object, the effective opening area of the intake passage passing through the carburetor main body is mechanically opened and closed by a throttle valve. A carburetor with a venturi portion formed in the intake passage for controlling; fuel stored in a fuel tank is pressurized by a fuel head difference or a fuel pump, and is supplied to a valve seat opening in a float chamber of the carburetor. Fuel inflow path;
A fuel increase passage having one end connected to the fuel inflow passage and the other end connected to the intake passage of the carburetor including the intake pipe; and an output of a throttle valve opening sensor arranged in the fuel increase passage for detecting the opening of the throttle valve. A control valve for controlling the opening and closing of the fuel increase passage and the amount of fuel flowing in the fuel increase passage by a control signal from a control circuit to which the output of a vehicle speed sensor for detecting the speed of the vehicle is inputted; The control valve was operated by the control signal from the control circuit to open the fuel quantity increasing passage within the range of the constant vehicle speed in which the valve opening was equal to or larger than the predetermined opening and the vehicle speed was set to the throttle valve opening. It is a thing.

[0010]

The control valve operates according to the control signal from the control circuit when the opening of the throttle valve is equal to or larger than a certain opening and the vehicle speed is within the range of the constant vehicle speed determined for the opening of the throttle valve. Open the fuel increase passage. According to this, the pressurized fuel in the fuel inflow passage is injected and supplied into the intake passage through the fuel increasing passage, and the lean mixture is suppressed. On the other hand, when the opening of the throttle valve is equal to or less than a certain opening and the vehicle speed is outside the constant vehicle speed range defined for the opening of the throttle valve, the fuel increase passage is kept closed by the control valve. Therefore, the fuel injection supply from the fuel increase passage into the intake passage is suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a fuel increasing device for a carburetor according to the present invention will be described below with reference to FIG. In this example,
It is an example in a sliding throttle valve type carburetor. Reference numeral 1 denotes a carburetor main body in which an intake passage 2 penetrates the inside thereof, and a sliding valve guide cylinder 3 is continuously provided upward from a substantially middle portion of the intake passage 2 and faces a lower recess of the carburetor main body 1. The float chamber main body 4 is disposed, and 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. Opening / closing driving force is applied to the valve seat 6 by the movement of 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 the throttle valve 9 rotates on the carburetor main body 1. The operation shaft 10 is freely supported mechanically by a link and a lever, and the operation lever 12 is integrally attached to the shaft end portion of the operation shaft protruding outside the carburetor body 1. An accelerator wire (not shown) to be pulled by a driver is attached to the operation lever 12. Therefore,
When the driver operates the accelerator wire, the operating lever 12 and the operating shaft 10 rotate, and this is transmitted to the throttle valve 9 via a lever, a link, etc., and the throttle valve 9 opens and closes the intake passage 2. become. Then, the venturi portion 11 is formed by the bottom portion 9A of the throttle valve 9 that opens into the intake passage 2 and the intake passage 2 that faces the bottom portion 9A. The opening area of the venturi portion 11 changes as the throttle valve 9 moves. (Forms a so-called variable venturi)

A jet needle 13 is integrally attached to the bottom portion 9A of the throttle valve 9, and the jet needle 13 is inserted into a needle jet 14 which is a fuel injection hole opening in the venturi portion 11. To be done. The needle jet 14 is connected to the main fuel jet 16 via a mixing nozzle 15 having an air bleed hole 15A, and an annular acceleration well W is formed on the outer circumference of the mixing nozzle 15 described above. In the acceleration well W, a liquid surface having substantially the same height as the constant liquid surface formed in the float chamber 5 is formed, and in the acceleration well W on the liquid surface, a main air passage communicating with the atmosphere is formed. Open. (Main air passage not shown)

On the other hand, the valve seat 6 has a fuel inflow passage 17
The fuel stored in the fuel tank T is supplied under pressure via the fuel tank T. When the fuel tank T is arranged below the carburetor body 1, the fuel in the fuel tank T is The fuel inflow passage 17 is pressurized by the fuel pump P.
When the fuel tank T is disposed above the carburetor body 1, the fuel in the fuel tank T (shown by the dotted line in FIG. 1) is pressurized by the fuel head difference and flows into the fuel inflow. It is supplied to the path 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, so that the fuel flows from the fuel inflow path 17 into the float chamber 5 through the valve seat 6. And the liquid level in the float chamber 5 rises up to a set constant level, the float valve 7 closes the valve seat 6 with the float 8, so that the float chamber 7 flows through the valve seat 6 from the fuel inflow passage 17. The supply of fuel to the inside of the float chamber 5 is stopped, whereby a constant liquid surface can be formed in the float chamber 5. The above is a conventionally known vaporizer.

A fuel quantity increasing unit 20 has one end connected to the fuel inflow passage 17 and the other end connected to the intake passage 2 or an intake pipe (not shown) connecting the intake passage 2 of the carburetor body 1 and the engine. It is a passage, and the opening position is not limited within the above range. In the present embodiment, the fuel quantity increase passage 20 is opened upstream of the throttle valve 9 (left side in FIG. 1). Reference numeral 21 denotes a control valve which is arranged in the fuel amount increasing passage 20 and controls the opening and closing of the fuel amount increasing passage 20. In this embodiment, the movable iron core 23 is attracted to the fixed iron core 24 by energizing the solenoid 22 to move the movable iron core 23. Valve part 25 formed integrally with
Used a normally closed solenoid valve that opens a valve seat 26 provided in the fuel quantity increasing passage 20. (This control valve 21 may be properly selected as long as it has a function (for example, a motor) that electrically opens and closes the passage without being a solenoid valve.)

Reference numeral 27 is a throttle valve opening sensor for detecting the opening of the throttle valve 9 with respect to the intake passage 2. Reference numeral 28 is a vehicle speed for detecting the speed (hereinafter referred to as vehicle speed) of a vehicle equipped with an engine equipped with a main vaporizer. It is a sensor.

Throttle valve opening sensor 27 and vehicle speed sensor 28
The output of the control valve 30 is input to the control circuit 30, and the control circuit 30 controls the control valve 2 under the condition that the throttle valve opening and the vehicle speed are determined.
A control signal for driving 1 is output. A specific example of the conditions under which the throttle valve opening and the vehicle speed at which the control signal for driving the control valve 21 is output from the control circuit 30 will be described below. The control circuit 30 drives the control valve 21 to drive the control valve 21 in a state in which the opening is equal to or more than 8 and within a constant vehicle speed range (50 km / hour to 110 km / hour) determined for the throttle valve opening. The control signal is output. For example, when the throttle valve opening is 4/8, the vehicle speed is in the range of 50 km / hour to 70 km / hour,
When the throttle valve opening is 6/8, the vehicle speed is 50 km / h to 90
The vehicle speed is in the range of 50 km / hour, and in the throttle valve opening of 8/8, the vehicle speed is in the range of 50 km / hour to 110 km / hour. The above-mentioned condition range is clearly indicated by the hatched range in FIG. 2, but this condition range is set to an optimum value when setting the carburetor for the engine and is not limited to the above condition.

Next, its operation will be described. First, a relatively low opening operation state in which the opening of the throttle valve 9 is 3/8 or less will be described. The throttle valve 9 has a constant opening (3/8 opening).
Since it has not been opened until then, the control signal for driving is not output from the control circuit 30 to the control valve 21. Therefore, the control valve 21 is in the inoperative state, and the valve portion 25 of the control valve 21 keeps the valve seat 26 closed, so that the increased fuel amount from the fuel amount increase passage 20 to the intake passage 2 is not supplied. During such a low opening operation, the venturi portion 11 is throttled to a small opening area by the throttle valve 9, and the flow velocity of the air flowing through the venturi portion 11 of this small opening and the intake passage downstream of the venturi portion 11 is increased. Since the negative pressure of the venturi portion 11 and the intake passage downstream of the venturi portion 11 rises and is maintained, the needle jet 14 as the main fuel system
Also, since the optimum fuel is sucked into the venturi section 11 and the intake passage 2 through the bypass hole and the pilot outlet hole (not shown) serving as the low speed fuel system and supplied to the engine, the operation of the engine is performed satisfactorily and relatively. Low vehicle speed (5
It is possible to obtain a desired vehicle speed (less than 0 km / hour).

Next, the throttle valve 9 is opened from the relatively low opening operation state where the opening is 3/8 or less, and the load state applied to the engine during the middle opening and high opening operations where the opening is 3/8 or more. When the load is light or medium, the engine speed is
Since the throttle valve 9 is opened to the middle and high openings and the load is not relatively large, the throttle valve 9 rises appropriately, and as a result, the flow velocity of the air flowing through the venturi portion 11 is increased and the negative pressure of the venturi portion 11 is increased. Since the fuel that is sufficiently increased and is appropriate for the negative pressure is sucked into the intake passage 2 from the needle jet 14, it is possible to obtain the appropriate vehicle speed according to the throttle valve opening. Specifically, referring to FIG. 2, the vehicle speed exceeds 70 km / hour at the throttle valve opening 4/8, the vehicle speed exceeds 95 km / hour at the throttle valve opening 6/8, and the throttle valve opening 8 At / 8, the vehicle speed is 110k
Over m / hour. That is, in such an operating state, the vehicle speed with respect to the throttle valve opening degree shown in FIG. 2 increases to a vehicle speed outside the shaded range. Therefore, a control signal for driving is not output from the control circuit 30 to the control valve 21, and the control valve 21 keeps the fuel quantity increasing passage 20 closed. As described above, the fuel is not increased from the fuel increase passage 20 during the middle and high opening operation of the throttle valve 9 and when the load applied to the engine is small and medium load, as described above. Since the negative pressure of the venturi section 11 is sufficiently increased, the optimum fuel is sucked out from the needle jet 14 as the main fuel system to the venturi section 11 and supplied to the engine to satisfy the operation of the engine. A desired medium or high vehicle speed can be obtained according to the opening degree.

The fuel amount increasing device for the carburetor according to the present invention has a special function in the following. First, the first is a driving state in which the vehicle speed is not sufficiently increased even though the throttle valve 9 is opened to a medium or high opening of 3/8 or more. Such a situation is a state in which the throttle valve 9 is opened to a medium or high opening degree and a high load is applied to the engine, and for example, a state where a steep slope is climbed up or a load is fully loaded. In such a state, the throttle valve 9 is opened to a medium or high opening degree of 3/8 or more, while the rotational speed of the engine is decreased due to the high load and the flow velocity of the air flowing through the venturi section 11 is decreased. Decreased, Venturi part 11
Due to the decrease in the negative pressure of, the amount of fuel sucked from the needle jet 14 into the intake passage 2 is reduced and the air-fuel mixture is diluted, so that an appropriate vehicle speed with respect to the throttle valve opening cannot be obtained. For example, when the throttle valve opening is 4/8, the vehicle speed is less than 70 km / hour, when the throttle valve opening is 6/8, the vehicle speed is less than 95 km / hour, and when the throttle valve opening is 8/8, the vehicle speed is 110 km. / Less than an hour, etc.
When this state is reached, the opening state of the throttle valve 9 is detected by the throttle valve opening sensor 27 and its output is output to the control circuit 30.
On the other hand, the vehicle speed is detected by the vehicle speed sensor 28, and its output is input to the control circuit 30.

When the outputs from the throttle valve opening sensor 27 and the vehicle speed sensor 28 are input to the control circuit 30, the control circuit 30 sends a control signal for driving the control valve 21 to the control valve 21. In the control valve 21 that receives the control signal, the movable iron core 23 is attracted to the fixed iron core 24, and the valve portion 25 opens the valve seat 26. According to this, a part of the pressurized fuel supplied into the fuel inflow passage 17 is separated from the fuel inflow passage 17 and is immediately injected and supplied into the intake passage 2 from the fuel increase passage 20. The throttle valve, together with the fuel sucked from the needle jet 14 to the venturi section 11, prevents leaning of the air-fuel mixture during high-load operation in which the throttle valve is opened to a medium or high opening degree, and the vehicle speed is set to open the throttle valve. The speed increases to an appropriate vehicle speed according to the vehicle. The supply of the increased fuel from the fuel increase passage 20 into the intake passage 2 is performed by the throttle valve 9
Is 3/8 or more and within the constant vehicle speed range defined for the throttle valve opening (in other words, the vehicle speed has not risen to the appropriate vehicle speed for the throttle valve opening). It is carried out. For example, a throttle valve opening of 4/8 is a constant vehicle speed range from a vehicle speed of 50 km / hour to a vehicle speed of 70 km / hour, and a throttle valve opening of 6/8 is a vehicle speed of 50 km / hour.
From the hour to the vehicle speed of 95 km / hour, and when the throttle valve opening is 8/8, the vehicle speed is from 50 km / hour to the vehicle speed of 110
It is a fixed range up to km / hour. Then, when the opening degree of the throttle valve 9 becomes equal to or less than 3/8 opening degree, or outside the constant vehicle speed range defined for the throttle valve opening degree (in other words, the vehicle speed appropriate for the throttle valve opening degree). If either or both of the conditions are met, the output of the control signal from the control circuit 30 for driving the control valve 21 is stopped, and the control valve 21 returns to its original position. Return and valve part 2
The valve seat 26 is closed by 5 to stop the fuel supply from the fuel increasing passage 20 to the intake passage 2.

Secondly, during the acceleration operation in which the throttle valve 9 is rapidly opened from a low opening to a middle opening and a high opening, the throttle valve 9 is in a low opening state, and the engine is running at a low speed. The vehicle is running and the vehicle speed is low. From this state, the driver pulls the accelerator wire to rapidly open the throttle valve 9 to a medium or high opening state and perform acceleration operation. Here, the behavior of fuel supply to the intake passage 2 when the throttle valve 9 is rapidly opened from a low opening state to a middle opening state is as follows. When the throttle valve 9 is in a low opening state, the engine speed keeps idling rotation (for example, 1200 RPM) or low rotation speed. In such a state, the fuel is a low speed fuel system such as a bypass hole and a pilot outlet hole (Fig. (Not shown) is sucked into the intake passage 2 to perform the low opening low speed operation of the engine. Next, when the throttle valve 9 is rapidly opened to a medium or high opening state from the low opening state of the throttle valve 9, the intake passage 2
The amount of air flowing inside is increased at once, and according to this, the negative pressure at the tip of the needle jet 14 opening in the intake passage 2 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 through the mixing nozzle 15 to increase the engine speed. In this state, the fuel in the acceleration well W is sucked out to the venturi section 11 via the needle jet 14.
Since the intake air negative pressure applied to the opening of the needle jet 14 temporarily increases slightly and the inflow of the main jet 16 is not limited,
This is because it is stored in the accelerating well W on the downstream side and is easily sucked out. However, even if the fuel in the acceleration well W is sucked out, the stored fuel in the acceleration well W is limited, so that the engine speed cannot be increased significantly. That is, even if the throttle valve 9 is opened to a medium or high opening degree, it is difficult to immediately increase the vehicle speed according to the throttle valve opening degree. By increasing the capacity of the acceleration well W, it is possible to increase the rotation speed during acceleration and increase the vehicle speed.
This is because the inner and outer diameters of the mixing nozzle 15 are determined in consideration of the drivability in other operating regions, so that the capacity of the acceleration well W is necessarily limited. In such a state, in the present invention, the throttle valve opening is opened to a medium or high opening of 3/8 opening or more, and the engine speed is higher than idling speed. They are detected by not increasing significantly and not increasing (cannot increase) to an appropriate vehicle speed according to the throttle valve opening. The outputs of the throttle valve opening sensor 27 and the vehicle speed sensor 28 are input to the control circuit 30, and the control circuit 30 outputs a control signal for driving 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 is injected and supplied into the intake passage 2, and the mixing during the acceleration operation is performed. It suppresses the leaning of the air and assists in increasing the rotation speed during acceleration, increasing the vehicle speed according to the throttle valve opening. When the engine speed is sufficiently increased by the supply of fuel from the fuel increase passage 20 and the vehicle speed is appropriately increased according to the throttle valve opening, the control circuit 30 outputs a control signal to the control valve 21. The output is stopped and the fuel supply from the fuel quantity increasing passage 20 is cut off. However, the engine speed is sufficiently increased and the vehicle speed is appropriately increased according to the throttle valve opening. From needle jet 14 as the main fuel system
Since a large negative pressure acts on the intake valve 2, fuel suitable for the middle and high opening operation of the throttle valve 9 is supplied from the needle jet 14 to the intake passage 2
I was able to suck it inside. The acceleration operation described above will be described with reference to a specific example with reference to FIG. 2. From the throttle valve opening of 2/8 and the vehicle speed of 30 km / hour, the throttle valve 9 is rapidly opened to the 4/8 opening and the vehicle speed is 60 km / hour. When it rises only until time, the outputs of the throttle valve opening sensor 27 and the vehicle speed sensor 28 are input to the control circuit 30, and the control circuit 30 outputs a signal for driving the control valve 21. According to this, the fuel is immediately supplied from the fuel increase passage 20 toward the intake passage 2, leaning of the air-fuel mixture is suppressed, the rotation of the engine is increased, and the vehicle speed can be increased according to the throttle valve opening. When the vehicle speed exceeds 70 km / hour, the output from the vehicle speed sensor 28 to the control circuit 30 is stopped, so that the output from the control circuit 30 to the control valve 21 is stopped.
As a result, the supply of fuel to the intake passage 2 is stopped.

Further, even during the intermediate acceleration operation in which the throttle valve 9 is rapidly opened from the intermediate opening, for example, the 4/8 opening to the 8/8 opening (fully opened), the negative pressure of the venturi section 11 is temporarily reduced. There is a case where the vehicle speed does not increase to a desired speed because the increase in the rotation speed is suppressed and the vehicle speed does not increase to a desired speed. Even in such a state, the control valve 21 performs the above operation by the signal output from the control circuit 30. Can be improved. Explaining with a specific example with reference to FIG. 2, when the throttle valve opening is 4/8 and the vehicle speed is 75 km / hour, the throttle valve 9 is opened to 8/8 opening (fully opened) and the vehicle speed rises only up to 95 km / hour, Outputs from the throttle valve opening sensor 27 and the vehicle speed sensor 28 are input to the control circuit 30, and a signal for driving the control valve 21 is output from the control circuit 30, whereby the control valve 21 opens the fuel quantity increase passage 20. Immediately, fuel is supplied toward the intake passage 2 to prevent leaning of the air-fuel mixture, and thus the rotation of the engine is increased and the vehicle speed can be increased according to the throttle valve opening. When the vehicle speed exceeds 110 km / hour, the output from the vehicle speed sensor 28 to the control circuit 30 is stopped, so that the output from the control circuit 30 to the control valve 21 is stopped, and the fuel to the intake passage 2 from the fuel increase passage 20 is stopped. Supply is stopped.

Further, the control signal output from the control circuit 30 to the control valve 21 is a drive pulse having the energization time Ti, the opening of the throttle valve 9 is 3/8 or more, and the vehicle speed is the throttle valve opening. Within the fixed vehicle speed range specified for
When the opening of the throttle valve 9 is in a constant opening state, the energization time Ti is shortened as the vehicle speed increases to reduce the amount of fuel supplied from the fuel increasing passage 20 to the intake passage 2, When the vehicle speed is a constant speed state, it is advisable to lengthen the energization time Ti as the opening degree of the throttle valve 9 increases to increase the amount of fuel supplied from the fuel increase passage 20 to the intake passage 2. This fuel control state is clearly shown in FIG. 3. In FIG. 3, the amount of fuel supplied from the control valve 21 is the smallest in the mesh range (referred to as a large flow rate), and the fuel amount in the solid hatching range follows the mesh range. 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 (called the small flow rate). According to the above, for example, when the throttle valve 9 has a constant 8/8 opening, the vehicle speed is 50 k.
The amount of fuel supplied to the intake passage 2 through the fuel increase passage 20 during the rise from m / hr to 110 km / hr can be gradually reduced to a large flow rate, a medium flow rate, and a small flow rate.
In particular, when the negative pressure of the venturi portion 11 is low and it is difficult to suck the fuel into the venturi portion 11 from the needle jet 14 (for example, the vehicle speed is 55 km / hour), it is possible to perform the fuel increase correction of a large flow rate. On the other hand, when the suction of the fuel from the needle jet 14 into the venturi section 11 is in a better state than the above state (for example, the state where the vehicle speed is 105 km / hour), it is possible to perform the small fuel increase correction. Engine drivability, emission of harmful exhaust gas,
It has an extremely large effect in terms of fuel economy.

Further, for example, the throttle valve 9 is changed from 2/8 opening to 4 /
In the acceleration state in which the vehicle speed is 60 km / hour and is opened up to 8 degrees, a small amount of fuel increase correction can be performed. On the other hand, the throttle valve 9 changes from 2/8 degrees to 8/8 degrees. In the acceleration state in which the vehicle speed was released up to 60 km / hour, it was possible to correct the fuel increase in the flow rate larger than that in the acceleration state, and it was possible to achieve the appropriate fuel correction for the acceleration operation.

Further, the large flow rate within the mesh range described above,
When the control valve 21 is controlled by arbitrarily changing the energization time Ti in each range of the medium flow rate in the solid line hatching range and the small flow rate in the dotted line hatching range, the fuel is supplied from the fuel increasing passage 20 into the intake passage 2. The fuel can be controlled more precisely and finely. Further, the control valve 21 may be a linear electromagnetic valve in which the valve portion 25 moves linearly with respect to the valve seat 26 so that the opening area thereof can be continuously changed.

Reference numeral 31 is a pressure regulator for always maintaining the pressure of the fuel flowing in the fuel quantity increasing passage 20 at a constant pressure, which is composed of a metal housing, the interior of which is constituted by a diaphragm and a fuel chamber and a spring. The fuel in the fuel increase passage 20 upstream of the fuel inflow passage 17 or the valve seat 26 flows into the fuel chamber from the inlet and pushes up the valve through the diaphragm to balance with the spring at the set pressure. The remaining fuel is returned to the fuel tank T, while the spring chamber is connected to the intake passage 2. According to this, since the fuel pressure flowing in the fuel increasing passage 20 is always kept constant, the controlled fuel amount is uniquely determined by opening the control valve 21, and is directed from the fuel increasing passage 20 to the intake passage 2. The supplied fuel could be controlled accurately. (Note that the pressure regulator 31 itself is publicly known and the details are not shown.)

Considering the fuel increase passage 20, first, the inlet may be directly connected to the fuel tank T located above the carburetor without branching from the fuel inflow passage 19, or from the carburetor. Fuel tank T in the lower position
To the intake passage 2 or an intake pipe (not shown), but particularly downstream of the throttle valve 9. (Fig. 1
(On the right side of), the fuel increase passage 2 is opened to the intake passage 2
Since the fuel supplied from 0 to the intake passage 2 reaches the engine for a shorter time, and the fuel supplied into the intake passage 2 does not collide with the throttle valve 9, the needle jet 14, etc., the fuel is smoothly supplied to the engine and the responsiveness is improved. Can be improved. Furthermore, although the sliding throttle valve type carburetor is used in the above embodiment, the same effect can be obtained in a butterfly type carburetor.

Further, FIG. 4 shows an embodiment in which the first embodiment of the fuel increasing device according to the present invention is combined with a carburetor having an accelerating device, which will be described below. (The same structures as those in FIG. 1 are designated by the same reference numerals and the description thereof is omitted.) 50 is an acceleration pump device having the following configuration. That is, 51 is the acceleration fuel pump chamber 52 and the atmosphere chamber 5.
The acceleration fuel pump chamber 52 has one end connected to the inside of the float chamber 5 and the acceleration fuel suction passage 55 in which the suction side check valve 54 is arranged, and one end of the acceleration fuel pump chamber 52. An acceleration fuel discharge passage 58, which is connected to the intake passage 2 via 56 and has a discharge side check valve 57 arranged therein, and a diaphragm spring 59 that presses the diaphragm 51 toward the atmosphere chamber 53 is contracted. To be done. The opening operation of the throttle valve 9 is performed by the operation lever 12 and the link 6
0, it is added to the diaphragm 51 via the pump lever 61. That is, according to the opening operation of the throttle valve 9, the diaphragm 51 reduces the chamber volume of the acceleration fuel pump chamber 52 by the pump lever 61 and pressurizes the acceleration fuel pump chamber 52, whereby the accumulation is performed in the acceleration fuel pump chamber 52. The fuel for acceleration thus generated is injected and supplied into the intake passage 2 through the acceleration nozzle 56. Then, at the other downstream end of the fuel increasing passage 20 similar to that of the first embodiment shown in FIG. 1, the acceleration fuel discharge passage 58 between the discharge side check valve 57 and the acceleration nozzle 56 is provided.
It is opened to.

According to the above structure, the supply of the increased fuel amount to the fuel amount increase passage 20 by the control valve 21 is similar to that of the first embodiment, but during acceleration operation, especially in the initial stage of acceleration, the acceleration well In addition to the fuel supply from W to the intake passage 2 via the needle jet 14, the acceleration pump device 50
Since it was possible to supply the acceleration fuel from the engine, it was possible to more smoothly start the rotation in the initial stage of acceleration.
That is, in the first embodiment, looking at the behavior of the fuel supplied from the fuel quantity increase passage 20 during the acceleration operation,
The vehicle speed sensor detects the vehicle speed when the throttle valve 9 is mechanically opened from a low opening degree to 3/8 opening degree or more and the vehicle speed is within a constant vehicle speed range defined for the throttle valve opening degree. Then, a signal is input to the control circuit 30.
Outputs a signal to the control valve 21 from the Venturi portion 11, changes the negative pressure of the Venturi portion 11, changes the negative pressure of the Venturi portion 11, sucks fuel from the needle jet 14 due to the negative pressure change, increases the rotation speed, and changes the vehicle speed. Rise → Vehicle speed sensor 2
The vehicle speed is detected by 8 and a time delay occurs, and the control valve 21
There is a slight delay in the fuel supply from the fuel increasing passage 20 to the intake passage 2 via the. On the other hand, according to the second embodiment, when the throttle valve lever 12 is rotationally operated to start the acceleration operation, the rotation of the throttle valve lever 12 causes the link 60,
It is synchronously transmitted to the diaphragm 51 via the pump lever 61, compresses the acceleration fuel pump chamber 52, and accelerates from the acceleration fuel pump chamber 52 to the acceleration fuel discharge passage 58 and the acceleration nozzle 56.
Since the accelerating fuel can be injected and supplied to the intake passage 2 via the, it is possible to prevent the time delay of the fuel supply from the fuel increasing passage 20 during the accelerating operation, thereby improving the acceleration performance in the initial stage of acceleration. Was created.

Further, since the other end on the downstream side of the fuel quantity increasing passage 20 is opened particularly in the acceleration fuel discharge passage 58 between the discharge side check valve 57 and the acceleration nozzle 56, the discharge side check valve 5 is provided.
The pressure of the check valve spring S for pressing the discharge valve seat 7 does not restrict the fuel pressure flowing in the fuel increasing passage 20. That is, when the fuel amount increase passage 20 is opened to the accelerated fuel discharge passage on the acceleration fuel pump chamber 52 side of the discharge side check valve 57, the pressure of the fuel flowing in the fuel amount increase passage 20 is greater than the pressing load of the check valve spring S. If it is not too large, it is impossible to supply the increased amount of fuel through the accelerated fuel discharge passage 58, and the discharge pressure of the fuel pump P is increased or the fuel head difference is sufficiently increased to increase the fuel pressure flowing in the fuel increase passage. There is a need.

Furthermore, since the opening of the fuel increasing passage 20 which opens to the intake passage 2 of the carburetor main body 1 is bored in the limited carburetor structure, the degree of freedom in design is small. By utilizing the accelerated fuel discharge passage 58 connected to the already-accelerated acceleration nozzle 56, it becomes easy to rotate the fuel increasing passage 20.

In the first and second embodiments, the amount of the increased fuel injected and supplied from the fuel increasing passage 20 into the intake passage 2 is determined by the setting work with the engine. Since a small amount of fuel of about 5 cc / min is sufficient, a passage diameter smaller than the effective passage diameter of the fuel increasing passage 20 is provided in the fuel increasing passage 20 on the downstream side (the side discharging to the intake passage 2) of the control valve 21. By disposing the control jet J and controlling the amount of fuel injected from the fuel increase passage 20 into the intake passage 2 by this control jet J, accurate control of the increased fuel becomes easy.

[0034]

As described above, the carburetor fuel amount increasing device according to the present invention has the following effects. In a carburetor that mechanically controls the opening and closing of the effective opening area of the intake passage with a throttle valve, the throttle valve opening is equal to or greater than a certain opening degree, and the vehicle speed is within a certain vehicle speed range determined with respect to the throttle valve opening degree. At the time of middle, high opening and low speed operation of the throttle valve in, the fuel pressurized positively is supplied from the fuel increase passage to lean the air-fuel mixture without depending on the negative pressure of the venturi section. Since it was able to be suppressed, the setting work of the carburetor was extremely easy and the engine performance could be significantly improved. During acceleration operation of the engine, the engine speed does not rise sufficiently even though the throttle valve is open to medium or high opening, and a proper vehicle speed corresponding to the opening of the throttle valve cannot be obtained. In this case, it is possible to improve the acceleration performance of the engine by supplying the fuel positively pressurized from the fuel quantity increasing passage into the intake passage, and suppressing the leaning of the air-fuel mixture during acceleration operation. Is. In addition, according to the use of the acceleration pump device and the fuel amount increasing device in combination, the acceleration fuel is supplied from the fuel increasing passage together with the supply of the acceleration fuel from the acceleration pump device during the period from the initial stage to the middle period to the final stage of the acceleration. Since pressurized fuel can be supplied, the acceleration of the engine can be further improved. The control of the amount of fuel in the fuel increase passage by the control valve is such that the opening of the throttle valve is constant when the throttle valve has a certain opening or more and the vehicle speed is within a constant vehicle speed defined for the throttle opening. In the open state, the fuel amount decreases as the vehicle speed increases, and when the vehicle speed is constant, the fuel amount increases as the throttle valve opening increases. The fuel control characteristics were able to meet the requirements of the engine within an extremely short time, and the engine performance could be significantly improved and the development efficiency could be significantly improved. According to the fact that one end of the fuel increase passage is opened to the fuel inflow passage and the other end is opened to the acceleration fuel discharge passage downstream of the discharge side check valve of the acceleration pump device, the acceleration of the already-accelerated acceleration pump device Since the fuel discharge passage can be used as a part of the fuel increase passage, the degree of freedom in designing the carburetor can be increased. Further, the discharge pressure of the fuel increased from the fuel increase passage has no influence on the closing force of the discharge side check valve. The discharge pressure of fuel can be optimally set. By opening the other end on the outlet side of the fuel increase passage into the intake passage on the engine side from the throttle valve, the distance between the opening of the fuel increase passage to the intake passage and the engine is shortened, and fuel is supplied to the engine. Can be performed instantaneously, and the collision of fuel with the jet needle, throttle valve, etc. after being injected into the intake passage can be reduced, so that the dynamic characteristics of the engine can be improved. By controlling the pressure of the fuel flowing through the fuel increase passage to a constant fuel pressure by the pressure regulator, the amount of fuel supplied from the fuel increase passage into the intake passage is uniquely determined by the control valve, so accurate fuel supply is ensured. Is made possible.

[Brief description of drawings]

FIG. 1 is an overall system diagram including a vertical cross-sectional view of a carburetor showing a first embodiment of a carburetor fuel amount increasing apparatus according to the present invention.

FIG. 2 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 relation to a throttle valve opening and a vehicle speed.

FIG. 3 is a diagram showing another example of a range in which an output for driving is output from the control circuit to the control valve in the relationship between the throttle valve opening and the vehicle speed.

FIG. 4 is an overall system diagram including a vertical cross-sectional view of a carburetor showing an embodiment in which the fuel amount increasing device for the carburetor of the first embodiment is applied to a carburetor equipped with an accelerator.

[Explanation of symbols]

 2 Intake passage 5 Float chamber 6 Valve seat 9 Throttle valve 11 Venturi part 14 Needle jet 17 Fuel inflow passage 20 Fuel increase passage 21 Control valve 27 Throttle valve opening sensor 28 Vehicle speed sensor 30 Control circuit 31 Pressure regulator 50 Acceleration pump device 56 Acceleration Nozzle 57 Discharge side check valve 58 Accelerated fuel discharge path T Fuel tank P Fuel pump J Control jet

Claims (6)

[Claims] 1. A carburetor in which an effective opening area of an intake passage passing through a carburetor body is mechanically controlled by a throttle valve and a venturi portion is formed in the intake passage; and fuel stored in a fuel tank. A fuel inflow passage for supplying pressure to the valve seat opening in the floating chamber of the carburetor by pressurizing the fuel head difference or fuel pump; one end of the carburetor is connected to the fuel inflow passage and the other end includes an intake pipe. From a control circuit which is arranged in the fuel increase passage and which is connected to the road; the output of a throttle valve opening sensor for detecting the opening of the throttle valve and the output of a vehicle speed sensor for detecting the speed of the vehicle are input. And a control valve for controlling the opening / closing of the fuel increase passage and the amount of fuel flowing in the fuel increase passage by a control signal of; Defined by A fuel amount increasing device for a carburetor, which operates a control valve in response to a control signal from a control circuit within a constant vehicle speed range to open a fuel amount increasing passage. 2. A throttle valve that mechanically controls opening and closing of an effective opening area of an intake passage penetrating the carburetor main body, a venturi portion formed in the intake passage, and mechanically in conjunction with opening operation of the throttle valve. A carburetor having an accelerating pump device that compresses the accelerating fuel pump chamber and injects accelerating fuel in the accelerating fuel pump chamber into the intake passage through the accelerating fuel discharge passage; A fuel inflow passage that is pressurized by a fuel head difference or a fuel pump and is supplied to a valve seat that opens into the float chamber of the carburetor; one end is connected to the fuel inflow passage, and the other end includes an intake pipe. And a fuel increase passage connected to the fuel increase passage, which is arranged in the fuel increase passage, and which receives an output of a throttle valve opening sensor for detecting the opening of the throttle valve and an output of a vehicle speed sensor for detecting the speed of the vehicle. Fuel by control signal A control valve for controlling the opening / closing of the fuel increase passage and controlling the amount of fuel flowing in the fuel increase passage; and, the opening of the throttle valve is equal to or more than a certain opening, and the vehicle speed is a constant determined with respect to the opening of the throttle valve. A fuel amount increasing device for a carburetor which operates a control valve by a control signal from a control circuit to open a fuel amount increasing passage within a range of vehicle speed. 3. The control of the amount of fuel in the fuel increasing passage by the control valve is carried out when the opening of the throttle valve is a certain opening or more,
In addition, when the vehicle speed is within a constant vehicle speed range determined with respect to the throttle valve opening, and the throttle valve opening is in a constant opening state, the fuel amount decreases as the vehicle speed increases, and the vehicle speed becomes constant. The fuel amount increasing device for a carburetor according to claim 1 or 2, wherein the fuel amount is increased in accordance with an increase in the opening degree of the throttle valve in the state. 4. The fuel injection passage according to claim 2, wherein one end of the fuel increasing passage is opened to a fuel inflow passage, and the other end is opened to an accelerated fuel discharge passage downstream of a discharge side check valve of the acceleration pump device. Carburetor fuel booster. 5. The fuel amount increasing device for a carburetor according to claim 1, wherein the outlet side of the fuel amount increasing passage is opened in the intake passage on the engine side of the throttle valve. 6. The fuel amount increasing apparatus for a carburetor according to claim 1, wherein the fuel pressure flowing through the fuel amount increasing passage is controlled to a constant fuel pressure by a pressure regulator.