JPH05280426A - Acceleration pump device of carburetor - Google Patents

Abstract

PURPOSE:To prevent fuel from becoming to have thin mixing ratio by discharging fuel from a fuel nozzle for a little while even after a throttle lever is stopped. CONSTITUTION:An air pump piston 17 connected to a throttle lever and a fuel pump piston 2 are provided in the acceleration pump cylinder 3 of a acceleration pump 1. Both pistons 17, 2 are connected to each other through an air chamber 21. A fuel passage 4 communicated with a fuel nozzle and a float passage 14a communicated with a float chamber are connected to a fuel chamber 12 formed with an acceleration pump piston and the inner wall part 3a of the acceleration pump cylinder 3, and an air passage 23 is connected to an air chamber. It is thus possible to discharge fuel from a fuel nozzle while the fuel pump piston 2 is stopped completely since the fuel pump piston is stopped by pressure of air gradually even if operation of the throttle lever is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accelerating pump device for a carburetor in which fuel is still discharged even after a throttle lever opens a throttle valve and stops its movement.

[0002]

2. Description of the Related Art When an internal combustion engine of an automobile or the like is operated at a low load and the load is suddenly increased due to a slope or the like, the accelerator pedal is depressed for acceleration to increase the opening of the throttle valve. However, if the throttle valve opening is suddenly increased, the negative pressure in the intake manifold becomes weaker, and the fuel discharge amount due to the negative pressure in the venturi of the carburetor becomes less than the amount of increase in air, and the required mixing There is a problem that it becomes thinner than the ratio. In the past, in order to compensate for this, not a negative pressure but a mechanical acceleration pump was connected to the throttle lever that rotates the throttle valve so that fuel is forcibly discharged only while the throttle lever is being moved. Was there.

An acceleration system for forcibly discharging fuel using the acceleration pump as described above will be described with reference to FIG. 4 and FIG. 3 showing an enlarged main part thereof. In the figure, the reference numeral 1 is an acceleration pump. The acceleration pump 1 includes a fuel pump piston 2 and an acceleration pump cylinder 3
And a check ball 5 provided in the fuel passage 4.

The fuel passage 4 is connected to a fuel nozzle (main) 8 that opens to a venturi 7 of the carburetor 6. The upper end of the fuel pump piston 2 is connected to the throttle lever 9, and the throttle lever 9 is also connected to the throttle valve 10.

An acceleration pump return spring 11 is interposed in the fuel pump piston 2 and constantly urges the fuel pump piston 2 in a direction to push it out of the acceleration pump cylinder 3, that is, to the throttle lever 9 side. Further, a fuel outlet 13 of the fuel passage 4 and a fuel inlet 15 from a float chamber 14 are opened in the fuel chamber 12 of the acceleration pump cylinder 3. In the figure, 16 indicates a fuel weight.

[0006] While the internal combustion engine of an automobile equipped with such an acceleration system is being operated at a low load, if the load increases suddenly on a slope or the like, the accelerator pedal (not shown) is depressed to move the throttle lever 9 to move the throttle. When the opening degree of the valve 10 is increased, at the same time, the movement of the throttle lever 9 causes the fuel pump piston 2 to advance in the fuel chamber 12 of the acceleration pump cylinder 3 to send the fuel from the fuel outlet 13 to the fuel passage 4 and the fuel from the fuel nozzle 8. I try to make it blow out.

As an acceleration pump device for a vaporizer, there is one disclosed in Japanese Utility Model Laid-Open No. 61-162564. In the one disclosed in this publication, an outlet check valve is provided between the acceleration pump and the acceleration nozzle, and an air introduction passage is connected to the downstream side of the outlet check valve.

[0008]

In the prior art described above, when the load suddenly increases on a slope or the like, the fuel is forcibly discharged from the fuel nozzle by the mechanical acceleration pump connected to the throttle lever. However, the fuel is discharged from the fuel nozzle only while the throttle lever is moving,
It takes time from the end of the discharge until the amount of discharge due to the negative pressure reaches the required amount, and there is a problem that the mixing ratio becomes thin during that time.

The accelerating pump device of the carburetor disclosed in Japanese Utility Model Laid-Open No. 61-162564 is provided with an outlet check valve between the accelerating pump and the accelerating nozzle, and an air introduction passage is provided downstream of this valve. Although they are connected, they do not solve the problem of the present invention because they do not push the piston of the acceleration pump by air.

The present invention has been made in order to solve the above-mentioned conventional problems, in which the fuel pump piston of the acceleration pump is moved by the air pushed by the air pump piston, and the fuel remains for a while even after the throttle lever is stopped. It is an object of the present invention to provide an accelerating pump device for a car carburetor that is capable of being discharged during a period of time.

[0011]

According to the present invention, as means for solving the above problems, an air pump piston connected to a throttle lever is slidably provided in the acceleration pump cylinder of an acceleration pump and the tip of the air pump piston is provided. A fuel pump piston for sending fuel through the air in the air chamber is slidably provided on the side, and the fuel chamber formed by the fuel pump piston and the inner wall of the acceleration pump cylinder communicates with the fuel nozzle of the carburetor. The fuel passage is connected to the float passage communicating with the float chamber, and the air passage is connected to the air chamber.

[0012]

As described above, according to the present invention, the air pump piston and the fuel pump piston are arranged in the acceleration pump cylinder of the acceleration pump, and both pistons are connected by the air in the air chamber. When the air pump piston moves forward by operating the lever,
The fuel pump piston also advances through a compressible gas called air, and the fuel in the fuel chamber is delivered to the fuel passage and discharged from the fuel nozzle. Even when the movement of the throttle lever stops and the forward movement of the air pump piston stops, the fuel pump piston does not stop at the same time as the air pump piston stops, but it gradually stops due to the air pressure. During this period, fuel can be discharged from the fuel nozzle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 by assigning the same reference numerals to the same members as those in FIGS. In the figure, reference numeral 1 is an acceleration pump integrally provided with the carburetor 6 of the automobile. An air pump piston 17 connected to a throttle lever 9 is slidably provided inside the acceleration pump cylinder 3 of the acceleration pump 1. The air pump piston 17 is held by penetrating a stopper wall 18 formed inside the acceleration cylinder 3.

An air pump return spring 19 is provided on the air pump piston 17. The air pump return spring 19 has one end abutted against the stopper wall 18 and the other end engaged with the protrusion 20 of the air pump piston 17 to constantly urge the air pump piston 17 toward the throttle lever 9 side. The throttle lever 9 is connected to the throttle valve 10 of the carburetor 6.

An air chamber is provided at the tip side of the air pump piston 17.
A fuel pump piston 2 for sending fuel to a fuel nozzle 8 opened in a venturi 7 of a carburetor 6 via 21 air is slidably provided. The fuel pump piston 2 has an acceleration pump return spring 11
Is installed. One end of the acceleration pump return spring 11 is brought into contact with the inner wall portion 3a of the acceleration cylinder 3, and the other end is engaged with the projection 22 of the fuel pump piston 2 so that the fuel pump piston 2 is constantly operated.
It is biased to the 17 side.

A fuel outlet 13 of a fuel passage 4 communicating with a fuel nozzle 8 of a carburetor 6 opens in a fuel chamber 12 formed by a fuel pump piston 2 and an inner wall 3a of an acceleration cylinder 3. Then, the float passage 14a communicating with the float chamber 14
The fuel inlet 15 of is open. A check ball 5 and a fuel weight 16 are provided in the middle of the fuel passage 4 to prevent the backflow of the fuel when the fuel is pushed out to the fuel nozzle 8. In addition, the air chamber 21
An air inlet 24 of an air passage 23 is opened in this.

Next, the operation of this embodiment will be described. As described above, the air pump piston 17 and the fuel pump piston 2 are arranged in the acceleration pump cylinder 3 of the acceleration pump 1, and both pistons 17 and 2 are connected by the air in the air chamber 21. When the air pump piston 17 moves forward by the operation of the throttle lever 9, the fuel pump piston 2 also moves forward via air, but even when the movement of the throttle lever 9 stops and the movement of the air pump piston 17 stops, the fuel pump piston 2 also moves forward. The piston 2 is not stopped at the same time as the air pump piston 17 is stopped, but is gradually stopped by the pressure of the air, so that fuel can be discharged from the fuel nozzle 8 until it is completely stopped.

The operation will be described below. First, when the throttle lever 9 is operated in the high load direction, that is, when the air pump piston 17 is pushed into the acceleration pump cylinder 3, the air pump piston 17 connected thereto moves downward in FIG. 23 is closed and the air in the air chamber 21 is compressed. Then, the compressed air pushes the fuel pump piston 2 downward, whereby the fuel pushes the check ball 5 and the fuel weight 16 provided in the fuel passage 4 upward, so that the passage is opened. As a result, the fuel passage 4
The fuel that has passed through is discharged from the fuel nozzle 8.

Immediately after the throttle lever 9 is actuated, the pressure in the air chamber 21 is high, so the check ball 5 and the fuel weight 16 move largely upward, and the discharge amount from the fuel nozzle 8 is large. Over time, the pressure in the air chamber 21 decreases, and the upward movement amount of the check ball 5 and the fuel weight 16 decreases, so that the ejection amount from the fuel nozzle 8 decreases.

Further, after a lapse of time, it becomes impossible to push up the check ball 5 and the fuel weight 16, and the discharge is completed. When the throttle lever 9 is operated in the low load direction, that is, when the air pump piston 17 is operated so as to be pushed out from the acceleration pump cylinder 3, the air pump return spring 19 and the acceleration pump return spring 11 cause the air pump piston 17 and the fuel, respectively. The pump piston 2 moves upward and prepares for the next movement in the high load direction.

As described above, while the throttle lever is stopped, the fuel discharge amount decreases with the passage of time, but the fuel continues to be discharged. Therefore, the fuel discharge due to the negative pressure in the venturi 7 starts, and the discharge amount becomes constant. The change of the mixing ratio is gentle until the temperature becomes high, and the transient characteristics are improved.

[0022]

Since the present invention is configured as described above, even after the movement of the throttle lever for discharging the fuel from the fuel nozzle has stopped, the fuel discharging does not stop immediately but for a while. During this period, the fuel is discharged from the fuel nozzle, so that the fuel is discharged by the acceleration pump until the fuel discharge amount by the negative pressure reaches the required fuel discharge amount as in the conventional case. Therefore. It does not have a thin mixing ratio.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an acceleration system showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the acceleration pump shown in FIG.

FIG. 3 is an enlarged sectional view of a conventional acceleration pump.

FIG. 4 is a schematic diagram of a conventional acceleration system.

[Explanation of symbols]

 1 acceleration pump 2 fuel pump piston 3 acceleration pump cylinder 4 fuel passage 6 carburetor 8 fuel passage 9 throttle lever 12 fuel chamber 14 float chamber 14a float passage 17 air pump piston 21 air chamber 23 air passage

Claims (1)

[Claims] 1. An acceleration pump cylinder of an acceleration pump is slidably provided with an air pump piston connected to a throttle lever, and a fuel pump piston for sending fuel through air in an air chamber is provided at a tip end side of the air pump piston. A slidably provided fuel chamber formed by the fuel pump piston and the inner wall portion of the acceleration pump cylinder is connected to a fuel passage communicating with a fuel nozzle of a carburetor and a float passage communicating with a float chamber. An accelerating pump device for a carburetor, characterized in that an air passage is connected to an air chamber.