JPS63138147A - Starting device for diaphragm type carburetor - Google Patents

Abstract

PURPOSE:To improve startability, by opening a fuel valve through a control lever, spring and a diaphragm being associated with operation in the time of this starting operation of an engine closing a choke valve so that fuel is allowed to smoothly flow into a fuel regulator chamber. CONSTITUTION:A diaphragm type carburetor, in which an intake passage 2 providing a choke valve C and a throttle valve V successively from the upstream side is formed 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 the fuel regulator chamber 4 provides in its inside a fuel value 11 which controls an inflow of fuel from a fuel tank T. While the chamber 4, to which an atmospheric air opening path 9 is opened, provides a one-way control valve 10, which is opened when the chamber 4 generates a positive pressure in the inside, to be interposed. Further the carburetor provides a spring 31 to be arranged 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 protrusive end part of said supporting lever 32.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is a carburetor that controls the amount and concentration of air-fuel mixture supplied to an engine, and in particular, a diaphragm provided in the carburetor body that connects a fuel regulator chamber and an atmospheric chamber. A diaphragm type carburetor that controls the opening and closing of a fuel valve seat provided at the end of the fuel inlet passage according to the negative pressure in the intake airway that acts on the diaphragm, thereby supplying air-fuel mixture to the engine. It is.

[Prior Art] When starting such a diaphragm type carburetor, it is necessary to supply fuel into the fuel regulator chamber in advance before starting the starting operation, and the intake passage is kept closed with a valve. There is a need.

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

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, a choke valve is operated to be fully closed using an operating wire or the like.

According to this, when the fuel valve opens the fuel valve seat, the priming fuel pump is operated to store fuel in the fuel regulator chamber, and then cranking operation is applied to the engine. 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. .

[Problem to be solved by the invention] This conventional starting device has 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 after the engine is started, it is necessary to immediately release the mechanical pressure on the diaphragm by the pressing member.

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. The air-fuel mixture becomes too rich, which is unfavorable for engine warm-up performance.

This phenomenon is particularly 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.

0 Before starting the engine, it is necessary to perform three operations: closing the choke valve, operating the pressing member, and operating the priming fuel pump, making the operation complicated and especially difficult for beginners to start. Not desirable.

[Means for solving problems]

The starting device for a diaphragm carburetor according to the present invention was developed in view of the above problems, and its main purpose is to improve the warm-up performance of the engine.

Another purpose is to improve starting operability.

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; A choke valve that controls the opening and closing of the intake passage that passes through the carburetor body, an operating lever that presses a second spring against the diaphragm when the choke valve closes, and a choke valve that closes the choke valve when the engine is started. By doing so, the operating lever is pressed to press the second spring against the diaphragm,
On the other hand, when the choke valve is opened, the operating lever is moved to position the second spring outside the operating range of the diaphragm.

[Operation] Before starting the engine, first, the choke valve applies a blocking action to the intake passage.

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

Next, when the engine is cranked, the pulsating pressure generated by the engine is introduced into the pressure receiving chamber of the fuel pump, and from the fuel pump into the fuel regulator chamber.

By repeating this cranking operation several times, fuel is stored in the fuel regulator chamber, and excess fuel is discharged from the atmosphere opening path.

On the other hand, negative pressure acts on the fuel nozzle due to the cranking operation of the engine, whereby the fuel in the fuel regulator chamber is sucked out into the intake passage, thereby making it possible to start the engine.

[Embodiment 1] Hereinafter, an embodiment of a starting device for a diaphragm type carburetor according to the present invention will be described with reference to the drawings.

Reference numeral 1 denotes a carburetor body in which an intake passage 2 passes through and a throttle valve V is arranged inside the intake passage 2, and a diaphragm 3 arranged on one side of the carburetor body 1 A fuel regulator chamber 4 and an atmospheric chamber 6 having an atmospheric communication hole 5 are formed on the opposite side thereof, and an intake passage 2 is further upstream of the throttle valve V.
Inside, a choke valve C for opening and closing the intake passage 2 is attached to the choke shaft H. Inside the fuel regulator chamber 4, there is a fuel valve seat 8 which is connected to the fuel inlet passage 7 which opens into the fuel tank T at one end, and an atmosphere opening passage 9 whose one end opens to the atmosphere. is fuel regulator chamber 4
A one-way control valve 10 is disposed to open the atmospheric release path 9 when the internal pressure becomes positive.

Therefore, this atmosphere opening path 9 is closed by the one-way control valve 10 when the pressure inside the fuel regulator chamber 4 is atmospheric pressure or negative pressure.

Furthermore, within the fuel regulator chamber 4 is a control rod rotatably supported by the bin 13! 4 is rotatably arranged, and the fuel valve 11 is arranged correspondingly to one end 14A of this control rod 14, and this fuel valve 11 is arranged opposite to the fuel inflow valve seat 8. Further, the other end 14B of the control rod 14 is locked to the diaphragm 3.

In addition, 15 is a fuel nozzle with one end opened to the fuel regulator chamber 4 and the other end opened to the intake passage 2, and 18 is a fuel nozzle that applies counterclockwise rotational force to the control rod 14 to move the fuel valve 11 to the fuel valve seat. It is an elastic member such as a spring that presses and urges the 8. 2
Reference numeral 3 denotes a fuel pump disposed in the fuel inflow path 7 that communicates the fuel inflow valve seat 8 and the fuel tank T, and is divided into a pressure receiving chamber 25 and a pump chamber 2B by a diaphragm 24. Engine pulsating pressure is introduced. Further, an inflow passage 28 having a suction side check valve 27 and an outflow passage 30 having a discharge side check valve 29 are opened in the pump chamber 2B. 3
Reference numeral 1 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 main body L, for example, and one end of this operating lever 33 connects to a choke lever 35 attached to the end of the choke shirt H. They are mechanically connected by a link 38 or the like, and the other end is disposed corresponding to the support rod 32.

As shown in FIG. 1, when the choke valve C is in the open state, the second spring 31 is arranged with a gap A separated by a light distance from the diaphragm 3, and in this state, the diaphragm 3 moves under the pulsating pressure of the engine. Even if the second spring 31 is in contact with the second spring 31,

On the other hand, when the choke valve C is operated in the closing direction using the operating wire 37, this operating force causes the choke lever 35 to rotate counterclockwise in the figure, causing the link 3B to also act counterclockwise on the operating lever 33. Applying rotational force in the direction to the second
By moving the spring 31 upward, the second spring 31 uses its elastic force to move the diaphragm 3 upward toward the fuel regulator chamber 4 side.

According to this, the control rod 14 also rotates clockwise about the bottle 13, so that the fuel valve 11 can maintain the fuel inflow 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 indexed to fully close the choke valve C.

According to this, the choke lever 35 rotates counterclockwise in the figure, and this rotational force is applied to the operating lever 3 from the link 3B.
3, 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 the diaphragm 3, the control rod 14 rotates clockwise about the bottle 13, so that the pressure on the fuel inflow valve seat 8 of the fuel valve 11 by the control rod 14 is released, so that the fuel inflow valve seat 8 is held open.

After that, when the engine is cranked, the pulsating pressure of the engine is introduced into the pressure receiving chamber 25 of the fuel pump 23, so that the fuel pump 23 transfers the fuel in the fuel tank T from the fuel inlet passage 7 to the fuel inlet valve seat 8. through fuel regulator chamber 4
introduced into the world. This is easily achieved since the fuel valve 11 has opened the fuel inlet valve seat 8 in the previous stage.

Then, when the fuel is discharged into the fuel regulator chamber 4, the pressure inside the fuel regulator chamber becomes a positive pressure state, and the one-way control valve 10 in the atmosphere opening path 9 is temporarily opened, and the pressure inside the fuel regulator chamber 4 is opened. Excess fuel flows out through the atmosphere opening path 9, and an appropriate amount of fuel can be maintained in the fuel regulator chamber 4.

On the other hand, according to the cranking operation of the engine, the negative pressure of the intake passage increased by the check valve C acts on the fuel nozzle of the intake passage 2, and the fuel in the fuel regulator chamber 4 is immediately transferred to the intake passage 2. It is possible to operate the engine by sucking it out.

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 and connects one end 14A' to 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 operation wire 37. According to this, the choke valve C is returned to the fully open state by the operation wire 37.
, a clockwise rotational force is applied to the operation lever 33, and the support rod 32 is returned to its original position downward in the figure, thereby maintaining the gap A between the diaphragm 3 and the second spring 31, and the movement of the diaphragm 3. The second spring 31 is arranged outside the range.

Therefore, during normal engine operation (when the choke valve is fully open), the second spring 31 is disposed outside the operating range of the diaphragm 3, and the fuel regulator chamber 4
Since the inside is maintained in a negative pressure state (negative pressure from the fuel nozzle 15 acts), the atmosphere opening path 9 is connected to the one-way control valve 1.
There are some that have a function similar to that of conventional diaphragm type vaporizers, in that they are kept closed at zero.

Furthermore, in order to reduce the number of cranking operations per engine and to store sufficient fuel in the fuel regulator chamber 4, this can be achieved by increasing the pump capacity of the fuel pump 23; At times, the fuel discharge pressure may become excessive and the controllability of the diaphragm 3 as a regulator may be inhibited. A normally closed check valve 41 that communicates with the fuel return passage 40 and opens the fuel return passage 40 when the pressure in the fuel return passage 40 rises above a certain level may be installed in the fuel return passage. According to this, when the discharge pressure of the fuel pump 23 rises above a certain pressure, the fuel flows back into the fuel tank T through the fuel return passage 40, so that an increase in fuel pressure can be suppressed and the above-mentioned problem can be solved.

Furthermore, in the one shown in FIG. 2, a one-way control valve 42 disposed in the atmosphere opening path 9 is mechanically interlocked with the one-way control valve 42 when the choke valve C is operated in the closing direction. A varnish-like hook 43A is provided at the end, and the head of the one-way control valve 42 is locked to this hook 43A.
The opening and closing of the atmosphere opening path 9 can be performed more reliably than in the case where the opening and closing are performed in response to changes in pressure. (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 step for starting, the fuel valve seat is opened, so that the engine cranking action operates the fuel pump, allowing fuel to flow smoothly into the fuel regulator chamber, and to prevent excess fuel from entering the fuel regulator chamber. This can be confirmed by the leakage of fuel from a road open to the atmosphere. Particularly, this preparatory step can be performed simply by a single operation of closing the check valve, without requiring any priming fuel pump operation.

During warm-up engine operation, 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 at the fuel valve. Therefore, excessive fuel is not supplied, and the warm-up operation with the choke valve closed can be performed smoothly, and it is not necessary to immediately return the control lever after starting the engine. Moreover, it was possible to significantly improve startability.

[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. 3#...Diaphragm, 4...Fuel regulator chamber, 6...Atmospheric chamber. 8...Fuel inflow valve seat, 9...Atmospheric release path, 1
1...Fuel valve, 10...One-way control valve,
23...Fuel pump, 31...Second spring. 33...operate/<+, 311--fist link.

Claims (3)

[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 biased toward closing the fuel valve seat. In the diaphragm type carburetor, the diaphragm type carburetor is provided with a fuel pump disposed in the fuel inlet passage, and further includes a fuel pump having a function of sucking in and discharging fuel during engine operation; a spring, a one-way check valve that is placed in an atmosphere opening path that communicates the regulator chamber with the atmosphere and can allow fluid to move from the regulator chamber to the atmosphere, and an intake passage that passes through the carburetor body to open and close it. and an operating lever that presses the second spring against the diaphragm when the choke valve is closed. By closing the choke valve when starting the engine, the operating lever is operated to press the second spring against the diaphragm. Press the spring 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 biased toward closing the fuel valve seat. In the diaphragm type carburetor, the diaphragm type carburetor is provided with a fuel pump disposed in the fuel inlet passage, and further includes a fuel pump having a function of sucking in and discharging fuel during engine operation; A spring, a choke valve that controls the opening and closing of the intake passage that passes through the carburetor body, an on-off valve that opens an atmospheric release passage that communicates the regulator chamber with the atmosphere when the choke valve is closed, and when the choke valve is closed. an operating lever for pressing the second spring against the diaphragm;
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 the diaphragm by operating a control lever. (3) 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 biased toward closing the fuel valve seat. In a diaphragm type carburetor, a diaphragm type carburetor is provided with a fuel pump arranged in series in the fuel inlet passage, and further has a function of sucking in and discharging fuel during engine operation; the diaphragm is pushed toward the fuel regulator chamber side. a second spring, a one-way check valve that allows fluid to move from the regulator chamber to the atmosphere, a choke valve that controls opening and closing of the intake passage passing through the carburetor body, and when the choke valve closes,
an operating lever that presses the second spring against the diaphragm; a fuel return passage that connects the fuel inlet passage on the downstream side of the fuel pump with the fuel tank; It consists of a normally closed check valve that opens the return passage, and when the engine is started, closing the choke valve causes the operation lever to press the second spring against the diaphragm, while the choke valve closes. A starting device for a diaphragm type carburetor, in which a second spring is placed outside the operating range of the diaphragm by operating a control lever during opening operation.