JPS6357860A - Accelerating device for carburetor - Google Patents

Abstract

PURPOSE:To improve the drivability of acceleration, by driving a solenoid valve in an acceleration fuel passage to be controlled through a series circuit formed by an automatic switch, which is responsively actuated even in the time from whatever operative condition the accelerating operation is performed, and by an operation switch closed when a vehicle is in driving operation. CONSTITUTION:Fuel in a fuel source 6 is pressurized by a pump P, and a device enables the fuel to be supplied into a float chamber 5 beside a carburetor main unit 1 through a fuel introducing path 7 and a fuel passage 8 while to an acceleration fuel nozzle 14 through an acceleration fuel passage 15 branching from and connecting with the fuel introducing path 7. A normally closed type solenoid valve S is provided interposing in the acceleration fuel passage 15, and said valve S is connected so as to form a series circuit with an operation switch H, opened when an engine is in operation, and an automatic switch T. And the automatic switch T is constituted providing a diaphragm 21 which acts in response to a difference between the pressure in the first receiving pressure chamber 22, introducing a negative pressure through a throttle member 29 and a check valve 30, and the pressure in the second receiving pressure chamber 23 directly introducing the negative pressure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a carburetor that supplies and controls a mixture to an engine.
In particular, the present invention relates to an acceleration device in a carburetor that injects fuel for engine acceleration into an intake passage in response to the sudden opening of a throttle valve.

[Conventional technology]

During accelerating engine operation where the throttle valve is suddenly opened, -
Accelerating by injecting fuel during acceleration to prevent the mixture from becoming lean over time? There are two types of acceleration devices: one is a mechanical type that mechanically extracts the rotation of the throttle valve to drive an acceleration pump, and the other is a mechanical type that uses the rotation of the throttle valve to drive an acceleration pump. There is a negative pressure type accelerator that drives a pump, and the accelerator according to the present invention relates to a negative pressure drive type accelerator.

Conventionally, such negative pressure driven accelerators are generally divided into a pump chamber and a pressure chamber by a diaphragm, and the pump chamber has a fuel suction passage connected to a fuel source via a suction side check valve. is connected, and a fuel discharge passage that communicates with the acceleration fuel nozzle via the discharge side check valve is also connected. Further, the pressure chamber is connected to the intake passage on the engine side of the throttle valve via a negative pressure introduction passage, and a spring is compressed within the pressure chamber.

When the throttle valve opens suddenly due to acceleration, the negative pressure in the intake tract on the engine side of the throttle valve decreases (approaches atmospheric pressure).
According to this pressure drop, the diaphragm uses the tension of the spring to reduce the volume inside the pump chamber and increase the pressure inside the pump chamber.According to this, the suction side check valve closes the fuel suction passage. On the other hand, the discharge side check valve opens the fuel discharge passage, whereby the fuel in the pump chamber is discharged from the acceleration fuel nozzle into the intake passage, thereby satisfying the acceleration operation of the engine.

[Problem that the invention seeks to solve]

However, such a conventional carburetor accelerator has the following drawbacks.

■The operating point of the diaphragm as an acceleration pump device is that it only operates below a certain level of intake airway negative pressure, and the intake airway airway negative pressure setting at which this operation starts must be done at a specific intake airway negative pressure during acceleration operation. It won't happen.

Looking at the negative pressure in the intake tract when the engine is operating, we can see that during normal operation, when the throttle valve of the carburetor is fully open during low-speed operation, and specifically when continuously climbing a slope with a heavy load loaded. The drop in the negative pressure in the intake tract is significant, and the diaphragm must not operate during such operation.For this reason, the negative pressure in the intake tract at the point where the diaphragm starts operating must be lower than this, and it is low. Since it is required to set the intake tract negative pressure, the setting range of the intake tract negative pressure is limited and there is little freedom.

■When the engine is accelerating, there is a slight acceleration operation in which the throttle valve is opened from a low opening to an intermediate opening, but the negative pressure in the intake passage cannot be expected to decrease significantly at this time, and the engine is operated at full throttle at low speed. It may be higher than the negative airway pressure at the time.

In such a state, there is a problem in that acceleration fuel cannot be supplied from the accelerator.

[Means for solving problems]

The accelerator device for a carburetor according to the present invention was created in view of the above-mentioned drawbacks, and its purpose is to maintain the accelerating operation of the engine in a good condition by operating the accelerator reliably during any accelerating operation of any engine. In order to achieve the above objective, an acceleration fuel passage is branched from the fuel introduction passage, which introduces the fuel in the fuel source into the fuel passage of the carburetor via the fuel pump, to the acceleration fuel nozzle that opens in the intake passage of the carburetor. A normally closed solenoid valve is arranged in the acceleration fuel passage, and in the electric circuit of the solenoid valve, a partition body divides the switch body into a first pressure receiving chamber and a second pressure receiving chamber, and a first pressure receiving chamber is provided. An elastic member for pressing the partition toward the second pressure receiving chamber is arranged in the pressure receiving chamber, and a switch opening/closing member is arranged in the partition for imparting an opening/closing operation to a switch that opens and closes the electric circuit of the solenoid valve. The second pressure receiving chamber is equipped with an automatic switch that introduces engine-side intake tract negative pressure from the throttle valve, and the engine-side intake tract negative pressure is introduced from the throttle valve into the first pressure receiving chamber through a passage restricting member. The operation switch is arranged in series so that it is closed when the machine is in operation and open when it is stopped.

[Effect]

According to such a carburetor accelerator, the intake passage negative pressure temporarily decreases during acceleration of the engine, and the pressure within the second pressure receiving chamber decreases in synchronization with the acceleration.

On the other hand, the high intake airway negative pressure that occurs during normal operation of the engine still remains in the first pressure receiving chamber, so a pressure difference occurs between the first pressure receiving chamber and the second pressure receiving chamber, and this pressure difference causes the first The partition moves toward the first pressure receiving chamber by overcoming the tension of the elastic member in the pressure receiving chamber.

Due to this movement, the switch is closed by the switch opening/closing member, and from then on, the negative pressure in the first pressure receiving chamber leaks through the passage restricting member, until the negative pressure in the first pressure receiving chamber is defeated by the tension of the elastic member. This is to keep the switch closed. When the negative pressure in the first pressure receiving chamber is overcome by the tension of the elastic member, the elastic member returns the partition to the second pressure receiving chamber, and the switch opening/closing member opens the switch from its original position. When this switch is opened, the solenoid valve closes the accelerating fuel passage, and when the switch is closed, the solenoid valve opens the accelerating fuel passage, thereby discharging the fuel pressurized by the fuel pump. is injected into the intake tract from an accelerating fuel nozzle.

〔Example〕

Hereinafter, a first embodiment of the vaporizer accelerator according to the present invention will be described.
This will be explained using figures.

Reference numeral 1 denotes a carburetor main body through which an intake passage 2 passes, and a venturi part V is formed in the middle of the intake passage 2, and a venturi part V is formed inside the intake passage 2 on the engine side (lower side in the figure) than the venturi part V. A throttle valve 4 is attached to a throttle valve shaft 3 rotatably supported by the carburetor main body l, and the amount of air supplied to the engine is controlled by opening and closing the throttle valve 4.

A float chamber 5 is formed on the side of the carburetor body 1, and fuel in a fuel source 6 is pressurized in the float chamber 5 by a fuel pump P, and is supplied to the carburetor body via a fuel introduction path 7. 1 fuel passage 8
will be introduced to

In addition, a float 1 rotatably supported on a shaft 8 is provided in the float chamber 5.
0 is arranged, and by the rotation of this float lO, a valve seat) 11 arranged at the open end of the fuel passage 8 to the float chamber 5 is opened.
An opening/closing action is given to the float valve 12 which opens and closes. That is, when the float 10 rotates counterclockwise in the figure, the float valve 12 moves away from the valve seat 11 to open the valve seat 11, while when the float 10 rotates clockwise in the figure, the float valve 12 moves away from the valve seat 11 to open the valve seat 11. It is pressed against the seat 11 to close the valve seat 11, thereby creating a constantly constant liquid level x- in the float chamber 5.
form x.

In addition, one end of 13 is immersed under a constant liquid level in the float chamber 5,
The other end is the main nozzle that opens into a portion of the venturi.

Reference numeral 14 denotes an acceleration fuel nozzle for injecting fuel for acceleration, which is arranged to protrude into the intake passage 2, and its location (above or downstream of the venturi part V) is not specified. This acceleration fuel nozzle 14 is connected to the fuel introduction path 7 through an acceleration fuel passage 15.

Further, a normally closed solenoid valve S is disposed in this acceleration fuel passage 15 to keep the passage closed at all times (when not energized), and this solenoid valve S opens and closes the acceleration fuel passage 15. A movable iron core 17 having an on-off valve portion 16 and this movable iron core 1
Fixed iron core 18, movable iron core 17 and fixed iron core 1 corresponding to 7
8, a spring 18, a movable iron core 17,
It consists of a coil 20 wound around a fixed iron core 18. The electric circuit of the solenoid valve S is connected in series with an operating switch H and an automatic switch T, which are closed when the engine is running and open when the engine is stopped.

To explain the automatic switch T, 20 is a switch body, and a first
Zero compartment body 2 divided into pressure receiving chamber 22 and second pressure receiving chamber 23
1 is integrally disposed with a switch opening/closing member 24 made of a conductive material, and terminals A and B as a switch are protruded into a second pressure receiving chamber 23 facing the switch opening/closing member 24. Terminals A and B are connected to the electrical circuit of solenoid valve S.

Further, the intake passage negative pressure in the intake passage 2 on the side of the engine from the throttle valve 4 is introduced into the second pressure receiving chamber 23 via the first negative pressure introducing passage 25 . An elastic member 26 such as a spring is compressed in the first pressure receiving chamber 22, and the elastic member 2B allows the partition body 21 to
is pressed toward the second pressure receiving chamber 23 (to the right in the figure).

Further, the first pressure receiving chamber 22 is connected to the intake passage 2 on the engine side from the throttle valve 4 via the second negative pressure introduction path 27, and the third
It is connected to the engine side intake passage 2 via a negative pressure introduction passage 2. A passage restricting member 29 such as an orifice is disposed in the second negative pressure introduction path 27 to restrict the passage of the second negative pressure introduction path, and a A one-way check valve 30 that only allows flow from the first pressure receiving chamber 22 to the intake passage 2 is disposed.

Next, with reference to FIG. 2, the negative pressure in the intake passage 2 on the engine side from the throttle valve 4, which is associated with the driving pattern of the vehicle, will be explained. First, point A is when the engine is stopped, and when the engine is running and idling, the score is 8 points - 0 points.
Next, when the engine is accelerated, the intake passage negative pressure temporarily drops to point D. After that, when the throttle valve 4 enters low opening operation, the intake passage negative pressure rises by -L above point E, and the intake air from point E to point F increases. Maintain negative pressure.

Next, when the throttle valve 4 is partially opened and acceleration is performed, the intake tract negative pressure at the G point decreases from the F point. During accelerated driving,
The reason why the decrease in the intake tract negative pressure is different at points D and G is because the opening ratio of the throttle valve 4 is different during acceleration, and the larger the opening, the greater the decrease in the intake tract negative pressure. and G
When the throttle valve 4 enters intermediate opening operation after the negative pressure in the intake duct has decreased, the H point - 3 is maintained, and then when the engine decelerates to idling operation, the engine rotation continues even though the throttle valve 4 is closed. Since the engine is rotating at a high speed due to inertial force, the intake passage negative pressure rises to a point, and then becomes the intake passage negative pressure at point L-M during idling operation.

Next, when the throttle valve 4 is opened to a high opening degree and accelerated, the engine drops to the N point, and after that, when the engine enters full-open low-speed operation, the O point becomes the P point. The reason why the intake passage negative pressure at point 0-P is lower than in other operating ranges except for acceleration operation is because the throttle valve 4 is fully opened.
Moreover, this is due to the low rotation of the engine.

Note that the intake tract negative pressure value at each point is based on a diagram, and this value changes depending on engine performance, gear, vehicle weight, etc. In the case where the intake passage has a negative pressure characteristic for engine operation, the elastic characteristic of the elastic member 26 is such that the pressure difference between the first pressure receiving chamber 22 and the second pressure receiving chamber 23 is 1150 mm.
The partitioning body 21 is set so that it can move toward the first pressure receiving chamber 22 (to the left in FIG. 1) when the condition becomes HH.

Next, the operation will be explained along the operating modes shown in FIG.

When the engine is started with the operation switch H closed and the engine is put into a fitting operation state, the negative pressure in the intake tract, which was at the atmospheric pressure point mA, is equal to point B = point C - 500 * m Hg.

Before starting, the first pressure receiving chamber 22 and the second pressure receiving chamber 23 of the automatic switch T are maintained at atmospheric pressure, but due to the generation of the intake passage negative pressure, the second pressure receiving chamber 23 and the first pressure receiving chamber 22
The negative pressure in the intake tract is introduced from each negative pressure introduction path 25, 27, 28, and the equal intake tract negative pressure -500m+■Hg is introduced into both pressure receiving chambers 22, 23, so the partition body 21 presses the partition 21 toward the second pressure receiving chamber (to the right in the figure) by the tension of the elastic member 26, and the switch opening/closing member 24 is held with a gap between the terminals A and B.
In such a state, the electric circuit of the solenoid valve S forms an open circuit, so that the on-off valve section 16 of the solenoid valve S keeps the acceleration fuel passage 15 closed and the fuel from the fuel pump P is discharged from the acceleration fuel nozzle 14. It's not something you can do.

Next, when accelerating operation is performed by opening the throttle valve 4 to a high opening degree from the 0 point of idling operation, the intake passage negative pressure in the intake passage 2 decreases to an atmospheric pressure of about < -10 mmHg as shown at point D, and then The throttle valve 4 enters a low opening operation state (for example, running at 40 km/h), and the intake passage negative pressure is raised and returned to 400+n Hg between points E and F.

In this acceleration driving poem, the intake tract negative pressure in the intake tract z is -500+
It drops from ++mHg to -10a+mHg,
This change in the intake passage negative pressure is immediately introduced into the second pressure receiving chamber 23 via the first negative pressure introduction path 25, and the pressure within the second pressure receiving chamber 23 is lowered to -10+am+Hg.

On the other hand, in the first pressure receiving chamber 22, a passage restricting member 29 is arranged in the second negative pressure introduction path 27, and a third negative pressure is introduced from the first pressure receiving chamber 22 into the third negative pressure introduction path 2B. Road 2
Since the one-way check valve 30 that only allows flow to the engine 8 is disposed, the intake tract negative pressure -500 layers Hg during idling operation is still maintained in the first pressure receiving chamber 22. According to this, the differential pressure between the first pressure receiving chamber 22 and the second pressure receiving chamber 23 is theoretically 1480 SanhoHg ((-5QOmm
Hg) -(-1QtsHg) ) negative pressure in the intake tract acts.

According to this, the pressure difference between the two pressure receiving chambers 22 and 23 is 115
Since it is 0as+Hg or more, the partition body 21 is the elastic member 2B.
The switch opening/closing member 24 is connected to terminals A and B and closes the electric circuit of the solenoid valve S, so that the solenoid valve The movable iron core 17 of S is attracted by the fixed iron core 18 and opens the opening/closing valve part 16 to open the acceleration fuel passage 15, so that the fuel pressurized by the fuel pump P is delivered from the acceleration fuel nozzle 14 into the intake passage 2. It is used to inject and supply to.

When operating such a switch, special attention must be paid to the first point. When the pressure difference between the second pressure receiving chambers 22 and 23 becomes -150+115Hg or more, the partition body 21 and the switch opening/closing member 24 operate. This means that during the acceleration operation, the intake tract negative pressure drops to -350 mm Hg in the process of dropping to the 0 point (the differential pressure between the first and second pressure receiving chambers 22 and 23). 115
0 mm Hg), the electromagnetic valve S can be started to be opened, and acceleration fuel can be injected and supplied from the carburetor to the engine from the initial stage of acceleration.

On the other hand, in this state, the high intake passage negative pressure remaining in the first pressure receiving chamber 22 gradually leaks into the second negative pressure introducing passage 27 via the passage restricting member 29, and the throttle valve 4 is opened at a low level. In the process of returning to point E during operation, the first pressure receiving chamber 2
2 and the second pressure receiving chamber 23 is -150+mm Hg or less, the tension of the elastic member 26 causes the partition 21 to move the switch opening/closing member 24 toward the second pressure receiving chamber (to the right in the figure). Then, the electric circuit of the solenoid valve S is opened again, and the opening/closing valve part 16 of the acceleration fuel passage 15 is closed, and the injection of acceleration fuel from the acceleration fuel nozzle 14 is stopped. It is something.

Next, when the throttle valve 4 is operated at a low opening to maintain -400 wm Hg, when the throttle valve 4 is operated at an intermediate opening (for example, 80 km).
To explain the acceleration operation state (slight acceleration) to m/H running), the intake tract negative pressure is -400 mm Hg F
point to G point of 12001 Hg, and then held at H point - 1 point in the intermediate opening operating state.

In this short acceleration operation, the intake tract negative pressure acts in each pressure receiving chamber as in the above state, and when the differential pressure between both pressure receiving chambers becomes -150 mm Hg or more during the acceleration process, the solenoid valve S is activated as in the above acceleration operation. Closes the electric circuit of the on-off valve section 16
The accelerating fuel passage is kept open, and then when the differential pressure between the two pressure receiving chambers becomes 11501 or less, the electric circuit of the solenoid valve S is opened again and the solenoid valve S is again closed. Then, when decelerating from such an intermediate opening operating state to a fitting operation, the engine still maintains high rotation due to inertia even though the throttle valve 4 is closed to the idling opening, so that the negative pressure in the intake passage becomes as small as a point. The pressure rises, and then the engine rotation decreases, resulting in a negative intake air pressure during idling operation, such as between point L and point M.

In this state, the negative pressure inside the intake passage 2 is -30 at one point.
0 mmHg to -800 mmHg at the point, and the -500m layer Hg difference between the negative pressures of the intake passages flows from the first negative pressure introduction path 25 to the second pressure receiving chamber 23, and from the second negative pressure introduction path 27. and from the third negative pressure introduction path 28 to the first pressure receiving chamber 22
In particular, the one-way check valve 30
The third negative pressure introduction path 28 and the first pressure receiving chamber 22 are connected through a large opening in response to the intake passage negative pressure of 0■■Hg. Therefore, since the same negative pressure in the intake passage acts in both pressure receiving chambers 22 and 23, the partition body 21 is pushed toward the second pressure receiving chamber 23, and the switch opening/closing member 14 holds the electric circuit of the solenoid valve S open. It is something that can be used.

Next, when the engine is accelerated from idling,
The intake passage negative pressure decreases to the N point, and when the engine enters full-open low-speed operation thereafter, the intake passage negative pressure becomes between the 0 point and the 2 point.

This acceleration operation is the same as the acceleration state from point 0 to point D, so the explanation will be omitted.

In addition, during such full-open low-speed operation, the throttle valve 4 is fully opened and the engine rotation is low, so the negative pressure in the intake passage 2 is 1100 mm Hg. However, the automatic switch according to the present invention Since T is operated with a differential pressure, there is no possibility of any malfunction.

Further, a one-way control valve 30 disposed within the third negative pressure introduction path 28
Although this can be effective in speeding up the response when the pressure in the intake passage 2 increases, it can also be eliminated by appropriately setting the diameter of the passage restricting member 29.

Further, the switch opening/closing member 24 and the switch portions of the terminals A and B are not limited to those in this embodiment, and may be changed to switches such as a magnet switch or a reed switch.

〔Effect of the invention〕

As described above, the vaporizer accelerator according to the present invention can produce the following special effects.

It is placed in the electric circuit of a solenoid valve that opens and closes the acceleration fuel passage as an accelerator.

■Starting the automatic switch operation is the first step. Since the partition body is moved by the differential pressure in the second pressure receiving chamber, it can respond to acceleration from any driving condition, and in particular, the throttle valve, which is often used in city driving, can be operated at a low opening. The switch can be operated reliably even during acceleration operation where the opening ratio is opened to an intermediate opening ratio, and this makes it possible to reliably supply the desired acceleration fuel during any acceleration operation and improve acceleration drivability. It was made.

■Also, as mentioned above, by operating the partition body using differential pressure, it can be used even in situations where the intake tract negative pressure drops significantly and approaches the intake tract negative pressure during acceleration operation, especially when the engine is running at full throttle and at low speed. , it is possible to eliminate malfunctions of the automatic switch, and this means that the automatic switch operation can be set very easily over a wide range, leading to improved acceleration.

■Furthermore, by making the partition respond based on this pressure difference, the pressure difference is based on the steady state of operation before acceleration, and the operation is based on the pressure difference relative to that, so accelerating fuel can be injected from the beginning of acceleration operation. This allows smooth acceleration operation.

■ By arranging a one-way check valve that only allows flow from the first pressure receiving chamber to the negative pressure introduction path side in the passage between the first pressure receiving chamber and the negative pressure introduction path, the This makes it possible to maintain the pressure in the first pressure receiving chamber at the same pressure as the pressure in the second pressure receiving chamber without any time delay, thereby increasing the responsiveness of the operation.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of a carburetor accelerator according to the present invention, and FIG. 2 is a diagram showing intake tract negative pressure characteristics in each running pattern. 111. Vaporizer body, 298. Inhalation tract, 460. Throttle valve, 14. ,,acceleration fuel nozzle, 15,,acceleration fuel passage, 1B,,opening/closing valve section,S,,,M,magnetic valve,
T10. Automatic switch i, chi, 21,, compartment body, 22.
,,first pressure receiving chamber, 23,,,second pressure receiving chamber, 24. ,,
Switch opening/closing member, 25. ,,first negative pressure introduction path, 2B,,,elastic member, 2? , , second negative pressure introduction path, 2
8. Third negative pressure introduction path.

Claims (1)

[Scope of Claims] 1. An acceleration fuel passage is connected from a fuel introduction passage that introduces the fuel in the fuel source into the fuel passage of the carburetor via a fuel pump to an acceleration fuel nozzle that opens in the intake passage of the carburetor. A normally closed electromagnetic valve is arranged in the acceleration fuel passage, and in the electrical circuit of the electromagnetic valve, a partition body divides the switch body into a first pressure receiving chamber and a second pressure receiving chamber, and a second pressure receiving chamber is provided. An elastic member is disposed in the first pressure receiving chamber to press the partition toward the second pressure receiving chamber, and
A switch opening/closing member for opening/closing the switch for opening/closing the electric circuit of the solenoid valve is arranged in the partition body, and on the other hand, the engine-side intake passage negative pressure is introduced from the throttle valve into the second pressure receiving chamber. Inside the pressure receiving chamber, there is an automatic switch that introduces negative pressure from the intake airway from the engine side through a passage restrictor through a throttle valve, and an operation switch that is closed when the engine is running and opened when the engine is stopped, which are arranged in series. Accelerator. 2. An acceleration fuel passage connected to an acceleration fuel nozzle opening in the intake passage of the carburetor is branched from a fuel introduction passage that introduces the fuel in the fuel source into the fuel passage of the carburetor via the fuel pump, and the acceleration fuel A normally closed solenoid valve is disposed in the passage, and a partition body divides the switch body into a first pressure receiving chamber and a second pressure receiving chamber, and a partition is provided in the first pressure receiving chamber. While arranging an elastic member that presses the body toward the second pressure receiving chamber,
A switch opening/closing member for opening/closing the switch for opening/closing the electric circuit of the solenoid valve is arranged in the partition body, and on the other hand, the engine-side intake passage negative pressure is introduced from the throttle valve into the second pressure receiving chamber. A negative pressure in the intake tract on the engine side from the throttle valve is introduced into the pressure receiving chamber through a passage restricting member, and a negative pressure introducing passage connecting the first pressure receiving chamber and the intake tract on the engine side from the throttle valve is introduced into the pressure receiving chamber. 1 An automatic switch equipped with a one-way control valve that only allows flow from the pressure receiving chamber to the intake tract, and which closes when the engine is running.
A carburetor accelerator consisting of a series of operating switches that open when stopped.