JPS63138148A - Starting device for diaphragm type carburetor - Google Patents

Abstract

PURPOSE:To permit fuel to smoothly flow into a fuel regulator chamber from a priming fuel pump, by opening a fuel valve through a control lever, spring and a diaphragm being associated with the starting operation of an engine when it is started closing a choke valve. CONSTITUTION:A diaphragm type carburetor, which forms an intake passage 2, providing a choke valve C and a throttle valve V successively from the upstream side, penetrating through a carburetor main unit 1, forms a fuel regulator chamber 4 and an atmospheric air chamber 6, partitioned by a diaphragm 3, in the carburetor main unit 1. Here a fuel valve 11, which controls an inflow of fuel from a priming fuel pump 17, is provided in the fuel regulator chamber 4. While an atmospheric air opening path 9 is opened to the chamber 4, and a one-way control valve 10, which is opened when a positive pressure is generated in the chamber 4, is provided. Further a spring 31 is provided being positioned on a supporting lever 32 in a surface side of the atmospheric air chamber 6, and one end of a control lever 33, actuated being associated with a choke lever 35 through a link 36, is adapted to the protruding end part of said supporting lever 32.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a carburetor that controls the amount and concentration of air-fuel mixture supplied to an engine, and in particular, a carburetor that is divided into a fuel regulator chamber and an atmospheric chamber by a diaphragm provided in the main body of the carburetor. This relates to a diaphragm type carburetor that controls the opening and closing of the fuel valve seat provided at the end of the fuel inlet passage according to the negative and positive air intake paths acting on the diaphragm, thereby supplying the air-fuel mixture to the engine. ,
In particular, the present invention relates to a starting device for a diaphragm carburetor that includes a fuel priming device that supplies fuel stored in a fuel tank within a fuel regulator chamber when starting the carburetor.

[Conventional technology]

When starting such a diaphragm carburetor, it is necessary to supply fuel into the fuel regulator chamber in advance before the starting operation, and it is necessary to keep the intake passage closed with a choke valve.

The former method of supplying fuel into the fuel regulator chamber is to place a priming fuel pump in the fuel inflow path upstream from the fuel valve seat, but when starting an engine, the fuel valve seat is connected to the fuel regulator The fuel valve is held closed by the elastic force of an elastic member contracted on a control rod in the room.

Therefore, before operating the priming fuel pump, it is necessary to mechanically press the diaphragm toward the fuel regulator chamber to mechanically open the fuel valve. To specifically achieve this, the diaphragm is pressed from the atmospheric chamber side with a pressing member such as a rod or lever. on the other hand,
The choke valve is pulled into a fully closed state by an operating wire or the like, and when the fuel valve seat is open, the priming fuel pump is operated to store fuel in the fuel regulator chamber. .

After that, the engine is given cranking action,
According to this, the choke valve increases the negative pressure in the intake tract, and this negative pressure is applied to the fuel nozzle, sucking out the fuel in the fuel regulator chamber into the intake tract and supplying it to the engine, making it possible to start the engine. It is something.

[Problem that the invention seeks to solve]

Such a conventional starting device alleviates the following problems.

■The diaphragm is mechanically pressed toward the fuel regulator chamber by a pressing member, and when starting the engine, the driver must use a locking means such as a click to hold the diaphragm in the pressed state because it is necessary to crank the diaphragm. .

After maintaining this state, the engine is cranked as described above to start the engine, but it is necessary to immediately release the mechanical pressure on the diaphragm by the pressing member after the engine is started.

If this pressure is not released, fuel will be supplied into the fuel regulator chamber from the fuel pump driven by the engine startup, but according to this, excess fuel will be supplied to the fuel regulator chamber and supplied to the engine. This phenomenon, in which the air-fuel mixture becomes too rich, which is unfavorable in terms of engine warming performance, is caused by mechanically and forcibly pressing the diaphragm with the pressing member. This is because the diaphragm sensed the weight of the fuel and moved toward the atmospheric chamber, inhibiting the fuel valve's ability to close the fuel valve seat.

Before starting the zero engine, it is necessary to perform two operations: closing the choke valve and operating the suppressing member, which complicates the operation and is not preferable, especially for beginners.

[Means for solving problems]

The diaphragm type carburetor starting device of the present invention was developed in view of the above problems, and its main purpose is to improve engine warm-up performance, and other purposes are to improve starting operability. The aim is to achieve this goal.

In order to achieve the above purpose, the following steps were taken.

a second spring that presses the diaphragm toward the fuel regulator chamber; a one-way check valve that is disposed in an atmosphere opening path that communicates the regulator chamber with the atmosphere and is capable of allowing movement of fluid from the regulator chamber to the atmosphere; Consisting of a choke valve that controls the opening and closing of the intake passage that passes through the carburetor body, and an operating lever that presses a second spring against the diaphragm when the choke valve is closed, the choke valve is closed when the engine is started. By.

The operating lever is used to press the second spring against the diaphragm, and when the choke valve is opened, the operating lever is moved to place the second spring outside the operating range of the diaphragm.

[Effect]

As a step before starting the engine, the choke valve first applies a closing action to the intake tract.

According to this, the second spring is moved by an operating lever that is interlocked with the choke valve, and the diaphragm is pressed toward the atmospheric chamber by the elastic force of the second spring, thereby holding the on-off valve open from the fuel valve seat.

Next, when the priming fuel pump is operated, the fuel in the fuel tank is introduced into the fuel regulator chamber through the fuel inlet passage and the fuel valve seat, thereby increasing the pressure in the fuel regulator chamber while storing fuel in the fuel regulator chamber. According to this, surplus fuel stored in the fuel regulator chamber opens a one-way check valve due to the pressure difference with the atmosphere, and is forced out to the atmosphere, and the driver confirms that this fuel is coming out and performs priming. Stop fuel pump operation. In this state, the storage of fuel in the fuel regulator chamber is completed.

Next, one engine is cranked to apply negative pressure from the intake passage to the fuel nozzle, and the fuel in the fuel regulator chamber is sucked out from the fuel nozzle to start the engine.

Then, when the engine warms up and the choke valve is returned to its fully open state, the second spring's elastic force on the diaphragm is released and the performance of a normal diaphragm carburetor is maintained.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the starting device for a diaphragm type carburetor according to the present invention will be described with reference to the drawings.

The intake passage 2 passes through the inside of l, and the intake passage? It is a carburetor body with a throttle valve V placed inside, and the diaphragm 3 is placed on one side of the carburetor body L. A fuel regulator chamber 4 is formed on one side, and an atmospheric chamber 6 having an atmospheric communication hole 5 is formed on the opposite side.

Furthermore, a choke valve C for opening and closing the intake passage 2 is attached to a choke shaft H within the intake passage 2 upstream of the throttle valve V. Inside the fuel regulator chamber 4 is a fuel valve seat 8, one end of which is connected to a fuel inlet passage 7 that opens into the fuel tank T.
An atmosphere opening passage 9 whose one end is open to the atmosphere is opened, and a one-way control valve 1 is provided in the atmosphere opening passage 9 which opens the atmosphere opening passage 9 when the pressure inside the fuel regulator chamber 4 becomes positive pressure.
0 is placed.

Therefore, when the pressure inside the fuel regulator chamber 4 is atmospheric pressure or negative pressure, the atmosphere opening path 9 is closed by the one-way check valve lO.

Furthermore, a control rod 14 rotatably supported by a pin 13 is rotatably disposed within the fuel regulator chamber 4, and the fuel valve 11 is disposed corresponding to one end 14A of the control rod 14. This fuel valve 11 is disposed opposite to the fuel inflow valve seat 8. Further, the other end 14B of the control rod 14 is engaged with the diaphragm 3.

In addition, 15 is a fuel nozzle with one end opening into the fuel regulator chamber 4 and the other end opening into the intake passage 2, and 16 a counterclockwise rotational force is applied to the control rod 14 to move the fuel valve 11 into the fuel valve seat. It is an elastic member such as a spring that presses and urges the 8. 1
Reference numeral 7 denotes a priming fuel pump, which includes a pump pressing member forming a pump chamber P, an inflow passage 20 connected to the pump chamber P and having a suction side check valve 18, and a discharge side temporary reverse valve 21. It consists of an outflow path 22 having a.

Further, 23 is a fuel pump, which is divided into a pressure receiving chamber 25 and a pump chamber 28 by a diaphragm 24.
5, the pulsating pressure of the engine is introduced. Also pump room 2B
An inflow passage 28 having a suction path +1 valve 27 and an outflow path 30 having a discharge path 1 valve 28 are opened. The inflow path 28 of the fuel pump 23 is connected to the fuel tank T, the outflow path 30 is connected to the inflow path 20 of the priming fuel pump 17, and the outflow path 22 of the priming fuel pump 17 is connected to the fuel inflow path 7. .

In the above example, the fuel tank knee fuel pump 23 and the priming fuel pump 17 are connected, but the fuel pump 23 and the priming fuel pump 17 may be connected in reverse. Reference numeral 31 denotes a second spring disposed facing the surface of the diaphragm 3 on the atmospheric chamber 6 side, and specifically, it is disposed on a support rod 32 in the atmosphere chamber 6, and this support rod 32 is connected to the atmosphere communication hole 5. penetrate and protrude. Reference numeral 33 denotes an operating lever rotatably supported on a shaft 34 provided on the carburetor body L, for example, and one end of this operating lever 33 is connected to a choke lever 35 attached to the end of the choke shaft H. are mechanically connected to each other by a link 38 or the like, and the other end is connected to the support rod 32.
are arranged correspondingly.

As shown in FIG. 1, when the choke valve C is in the open state, the second spring 31 is disposed with a gap A separated by light from the diaphragm 3, and in this state,
Even when the diaphragm 3 moves under the pulsating pressure of the engine, it does not come into contact with the second spring 31. On the other hand, when the choke valve C is moved in the closing direction by the operation wire 37, this operating force is The choke lever 35 is rotated counterclockwise in the figure, and the link 38 is applied to apply a counterclockwise rotational force to the operation lever 33, and the second spring 31 is moved L, so that the second spring 31 becomes elastic. With force, move the diaphragm 3 upward toward the fuel regulator chamber 4 side.

According to this, the control rod 14 also rotates clockwise about the pin 13, so that the fuel valve 11 can hold the fuel inlet valve seat 8 in an open state.

Next, we will discuss the starting method.

First, as a first step of starting, the operating wire 37 is pulled to bring the choke valve C into a fully closed state. According to this, the choke lever 35 rotates counterclockwise in the figure,
This rotational force is transmitted to the operating lever 33 through the link 3B, and the operating lever 33 also rotates counterclockwise. According to this, the other end of the operating lever 33 presses the bottom of the support rod 32 to move it upward in the figure, and the second spring 31 is used to elastically press the diaphragm 3 toward the fuel regulator chamber 4 side. According to this movement of diaphragm 3,
Since the control rod 14 rotates clockwise about the bin 13, the control rod 14 releases the pressure on the fuel inflow valve seat 8 of the fuel valve 11, so that the fuel inflow valve seat 8 is maintained in an open state. It is.

Next, as the second stage of startup, the priming fuel pump 17 is operated, and the expansion and contraction of the volume of the pump chamber P causes the suction side advance W valve 19. Due to the synergistic action with the discharge side inverted valve 21, the fuel in the fuel tank T is forced into the fuel inlet passage 7 via the fuel pump 23, and the fuel is supplied to the fuel inlet valve seat 8. In such a state, the fuel inflow valve seat 8 is opened as the first stage of starting, so
This fuel is immediately supplied into the fuel regulator chamber 4.

Therefore, fuel is stored in the fuel regulator chamber 4 by repeating the pumping operation of the priming fuel pump 17. On the other hand, looking at the change in pressure inside the fuel regulator chamber 4, we see that the priming fuel pump 17
When the fuel is pumped from the fuel regulator chamber 4,
The inside of the fuel regulator chamber 4 is in a positive pressure state, and when the one-way control valve 10 in the atmosphere opening passage 9 receives the positive pressure inside the fuel regulator chamber 4, the atmosphere opening passage 9 is temporarily opened.

That is, during the discharge operation of the priming fuel pump 17, the atmosphere opening passage 9 is held open by the one-way control valve 10. Therefore, in order to know that sufficient fuel has been stored in the fuel regulator chamber 4 by repeating the operation of the priming fuel pump 17, the atmosphere opening passage 9 must be opened at a relatively high position in the fuel regulator chamber 4. Accordingly, the outflow of fuel from the atmosphere opening path 9 can be visually confirmed.

Next, when the engine is started by cranking, a negative pressure is generated in the intake passage 2 due to the cranking, and this negative pressure causes the fuel in the fuel regulator chamber 4 to be transferred from the fuel nozzle 15 into the intake passage 2. The air is sucked out and supplied to the engine, thereby making it possible to start the engine.In particular, the choke valve C restricts the amount of air and increases the negative pressure applied to the fuel nozzle 15, so that a rich air-fuel mixture can be avoided. It is possible to supply.

When the engine has completely exploded and entered a warm-up operation state, fuel automatically flows into the fuel regulator chamber 4 from the fuel pump 23 via the fuel inflow valve seat 8 due to engine operation, and excess fuel is removed. Although there is a risk of being supplied, in the present invention,
When excess fuel is supplied onto the diaphragm 3, the weight of the fuel overcomes the elastic force of the second spring and moves the diaphragm 3 downward in the figure. Control rod 1 by force
4 rotates counterclockwise to connect one end 14A' and the fuel valve 1.
1 is pressed against the fuel inflow valve seat 8 to suppress the inflow of fuel from the fuel inflow path 7.

Therefore, since excess fuel is not supplied into the fuel regulator chamber 4, such warm-up operation can be performed satisfactorily. When the warm-up of the engine is completed, the choke valve C is returned to the fully open state by the operating wire 37. According to this, the choke lever 35, the link 3B, and the operating lever 33 receive a clockwise rotational force. The provided support rod 32 is returned to its original position downward in the figure to maintain the gap A between the diaphragm 3 and the second spring 31, and the second spring 31 is disposed outside the operating range of the diaphragm 3.

Therefore, during normal engine operation (when the choke valve is fully open), the second spring 7 31 is disposed outside the operating range of the diaphragm 3, and the inside of the fuel regulator chamber 4 is maintained at a negative pressure ( (Negative pressure from the fuel nozzle 15 is applied.) Therefore, the atmosphere opening path 9 is kept closed by the one-way control valve 10, and the operation is similar to that of a conventional diaphragm type carburetor.

Further, in the one shown in FIG. 2, a one-way control valve 40 disposed in the atmosphere opening path 9 is mechanically interlocked with the one-way control valve 40 when the choke valve C is operated in the closing direction. A varnish-like hook 41A is provided at the end, and the head of the one-way control valve 40 is locked to the hook 41A.Compared to the one that responds to pressure changes, the atmosphere opening path 9
can be opened and closed more reliably. (The components in the drawings are the same as those in FIG. 1, so their explanations are omitted.) [Effects of the Invention] As described above, the diaphragm type carburetor of the present invention has the following effects in particular. .

■As a preparatory stage for starting, the fuel valve seat is opened, so that fuel flows smoothly from the priming fuel pump into the fuel regulator chamber, and the state of fuel storage in the fuel regulator chamber is controlled by the atmosphere opening path 9. This can be confirmed by the leakage of fuel. In particular, this preparatory step can be carried out simply by a single action of closing the choke valve.

■When the engine is warmed up, if excess fuel is supplied to the fuel regulator chamber, the diaphragm automatically moves down against the force of the second spring and closes the fuel inflow valve seat with the fuel valve. Therefore, excessive fuel is not supplied, and therefore warm-up operation with the choke valve closed can be performed well, and it is not necessary to return the operating lever immediately after starting the engine, improving starting operation and starting performance. We were able to achieve a significant improvement in this.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing one embodiment of a diaphragm type carburetor according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of a main part showing another embodiment. 300. Diaphragm, 400. fuel regulator,
668. atmospheric chamber, 801. Fuel inlet valve seat, 9
00. Atmospheric open road, 11. ,, fuel valve, 10. ,, one-way control valve, 17. ,, fuel pump for priming,
23. ,, fuel pump, 31,, second spring,
33. ,,operation lever, 3B,,,link, C00
, choke valve, Too, fuel tank. Kaya 2G

Claims (2)

[Claims] (1) A diaphragm placed on one side of the carburetor body divides the carburetor into a fuel regulator chamber and an atmospheric chamber, and a control rod corresponding to the diaphragm and rotatably supported is placed in the fuel regulator chamber. One end of the control rod is equipped with a fuel valve that controls the opening and closing of the fuel valve seat located at the end of the fuel inflow path leading to the fuel tank, and the other end is equipped with a fuel valve that controls the opening and closing of the fuel valve seat. comprising an elastic member that biases;
Further, in a diaphragm type carburetor, a priming fuel pump having a function of sucking in and discharging fuel and a fuel pump having a function of sucking in and discharging fuel during engine operation are arranged in series in the fuel inlet passage; a second spring that presses the fuel regulator chamber toward the fuel regulator chamber; a one-way check valve that is disposed in an atmosphere opening path that communicates the regulator chamber with the atmosphere and is capable of allowing movement of fluid from the regulator chamber to the atmosphere; It consists of a choke valve that controls the opening and closing of the intake passage that passes through the engine body, and an operating lever that presses a second spring against the diaphragm when the choke valve closes.The choke valve closes when the engine is started. By pressing the operating lever, the second spring is pressed against the diaphragm,
On the other hand, a starting device for a diaphragm type carburetor, in which a second spring is placed out of the operating range of the diaphragm by operating a control lever when a choke valve is opened. (2) A diaphragm placed on one side of the carburetor main body divides the carburetor into a fuel regulator chamber and an atmospheric chamber, and a control rod corresponding to the diaphragm and rotatably supported is placed in the fuel regulator chamber. One end of the control rod is equipped with a fuel valve that controls the opening and closing of the fuel valve seat located at the end of the fuel inflow path leading to the fuel tank, and the other end is equipped with a fuel valve that controls the opening and closing of the fuel valve seat. comprising an elastic member that biases;
Further, in a diaphragm type carburetor, a priming fuel pump having a function of sucking in and discharging fuel and a fuel pump having a function of sucking in and discharging fuel during engine operation are arranged in series in the fuel inlet passage; a second spring that presses the engine toward the fuel regulator chamber, a choke valve that controls the opening and closing of the intake passage passing through the carburetor body, and an atmosphere opening passage that communicates the regulator chamber with the atmosphere when the choke valve is closed. an on-off valve, and an operating lever that presses a second spring against a diaphragm when the choke valve is closed;
When the engine is started, the choke valve is closed, the operating lever is pressed to press the second spring against the diaphragm, and the opening/closing valve is opened to the atmosphere, while the choke valve is opened. In,
A starting device for a diaphragm type carburetor, in which a second spring is placed outside the operating range of a diaphragm by operating a control lever, and an air release path is closed by an on-off valve.