JPH01163447A - Starting device for carbretor - Google Patents

Abstract

PURPOSE:To enable the feed of desired starting fuel through simple constitution, by providing a starting fuel pump chamber to feed starting fuel by means of a control lever. CONSTITUTION:A starting fuel pump chamber 21 is situated away from a float chamber 4 of a carburetor. A starting fuel inflow passage 24 and a delivery passage 28 opened to an intake air pass 2 are opened to the starting fuel pump 21. An on-off valve part 33 positioned facing a valve seat 32 of the delivery passage 28 is integrally situated to a partition body 20, and a control lever 34 is integrally situated. With the control lever 34 pulled leftward during the starting of an engine, fuel in a float chamber 4 is sucked in the starting fuel pump chamber 21. When the lever is then released from a hand, the partition body 20 is moved rightward through the spring force of a spring 37, and starting fuel is delivered in the intake air pass 2. The control lever 34 is locked in the middle by means of an intermediate position regulating member N, and fuel is sucked out through a delivery passage 28 during warming-up running.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a carburetor that controls the concentration and amount of a mixture supplied to an engine, and particularly to a carburetor that supplies a rich mixture when starting an engine. This relates to a starting device for a two-stroke engine. [Prior Art] Conventionally, a commonly used starting device for a two-stroke engine carburetor has a choke valve placed in the intake duct of the carburetor to shut off the choke when starting the engine. - A so-called choke type valve that holds the intake duct in a fully closed state is connected by a starting passage before and after a throttle valve placed in the intake duct, and a starter on-off valve is placed in the starting passage. There is a so-called starter type that uses a starter on-off valve to keep the starting passage open during startup.

[Problem that the invention seeks to solve]

Such conventional starting devices have the following problems.

That is, according to the former, when the choke valve is closed and the engine is cranked during startup, the negative pressure in the intake tract generated by this cranking is increased by the choke effect of the choke valve, and the low-speed nozzle opening in the intake tract is increased. , the increased intake air negative pressure acts on the nozzle holes such as the main nozzle, sucking out fuel from the nozzle holes and supplying starting fuel to the engine, but at low speeds reaching these low speed nozzle holes. The fuel system or the main fuel system leading to the main nozzle is operated at low speed or during engine operation, respectively.

Settings are made to suit high-speed operating conditions, and in order to adjust the low-speed fuel system and main fuel system to satisfy the starting conditions, a lot of time is spent on setting to suit the conditions. .

In other words, when changing the low-speed fuel system or main fuel system set at -.degree to improve starting performance, it is necessary to test the low-speed fuel system and main fuel system again to confirm. It is.

Also, according to the latter, since the low-speed fuel system and the main fuel system have a starting passage as completely separate systems, unlike the former, there is no connection between the low-speed fuel system and the main fuel system, making the setting work easier. When the throttle valve is opened at the time of starting the engine, it is difficult to obtain a high intake tract negative pressure in the intake tract, which may make it impossible to suck out the starting fuel, resulting in poor starting performance.

[Means for solving problems]

In view of the above drawbacks, the carburetor starting device according to the present invention has the following features:
The object of the present invention is to provide a device with good starting performance that is easy to set up for improving starting performance and can supply optimal starting fuel for initial explosion, complete explosion, and warm-up of the engine. The purpose is to have excellent durability and maintain stable performance over a long period of time.To achieve the above purpose, the float chamber body 3 is placed on the side of the carburetor body l, through which the intake passage 2 passes. , in a carburetor in which a float chamber 4 in which a constant liquid level is stored is formed by a vaporizer main body 1 and a float chamber main body 3;
The starting fuel pump chamber 21 has a suction bias valve 25 arranged therein, a starting fuel inlet passage 24 connected to a constant liquid level below the float chamber 4, and a discharge control valve inside. Reverse 1hi valve 3
The starting fuel discharge passage 2 in which the starting fuel discharge passage 1 is disposed is opened, and the partition body 20, which is further pressed toward the starting fuel pump chamber 21 side by a spring 37, has an on-off valve portion 33 that can control the opening and closing of the starting fuel discharge passage. and an operating rod 34 that can apply a pump operating force to the partition body 20, and the operation rod has a starting fuel discharge passage 2 connected to the opening/closing valve portion 33 of the partition body 20.
An intermediate position regulating member N capable of holding the partition body 20 at a substantially intermediate position between a first state in which it is closed and a second state in which the partition body 20 is pulled toward the atmospheric chamber 22 is provided, and the gravitational force on the operating rod 34 is reduced from the second state. When released, the spring force of the spring 37 automatically returns the partition body 20 to approximately the intermediate position, and the starting fuel pump chamber 2
This is a starting device for a carburetor that discharges the fuel in 1 through a starting fuel discharge passage 28.

[Effect]

When starting the engine, the operating rod is pulled toward the atmospheric chamber to increase the volume of the starting fuel pump chamber and draw the fuel in the float chamber into the starting fuel pump chamber.

Then, the attractive force on the operating rod is released, leaving the operating rod in a free state. Then, the operating lever is automatically moved toward the starting fuel pump chamber by the spring force of the spring, and the movement of the operating lever toward the starting fuel pump chamber is determined by the intermediate position regulating member.

According to this, the fuel in the starting fuel pump chamber is injected and supplied from the starting fuel discharge passage into the intake passageway to prepare for the initial explosion and complete explosion of the engine. When the engine is started under such conditions and the engine completely explodes and enters warm-up operation, the negative pressure generated in the intake pipe opens the discharge side check valve and warms up the starting fuel from the discharge path into the intake pipe. The engine is warmed up by supplying sufficient fuel for the engine.

Next, when the warm-up operation is completed, a pressing force is applied to the operating rod to further return the operating rod to the starting fuel pump chamber. According to this, the opening/closing valve portion blocks the starting fuel discharge passage, so that the starting fuel is discharged. The supply of starting fuel from the road to the engine is stopped.

When the engine is running, even if the discharge side check valve opens, the opening/closing valve section will be sucked into the valve seat and will block the starting fuel discharge passage that opens inward of the valve seat, so it will not be able to move against the compartment body. Therefore, the negative pressure in the intake passage does not act to deform the compartment.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to FIG.

1, an intake passage 2 passes through the interior thereof, a float chamber body 3 is disposed on the side of the carburetor body 1, and a float chamber 4 is formed by the lower recess of the carburetor body 1 and the float chamber body 3. Ru. 5 is a valve seat connected to the fuel inlet H and opened into the float chamber 4; a float valve 6 is movably disposed corresponding to the valve seat 5;
is arranged in the float chamber 4 and is arranged corresponding to the float arm 7 of the float 9 which is rotatably supported by the pin 8 by the float arm 7. The rotation of the float 9 relative to the bin 8 causes the float arm 7 to control the opening and closing of the valve seat 5 in the float valve 6.

Reference numeral 10 designates a main nozzle as the main fuel system, the tip of which protrudes into the intake passage 2 and opens, and the other end is placed below a constant liquid level x-x formed in the float chamber 4. Connected to main fuel jet) 11. Further, 12 is a throttle valve that controls opening and closing of the intake passage 2.

The structure described below is a conventionally known technology, and the carburetor starting device according to the present invention has the following configuration in order to achieve the above object.

That is, 20 is a partitioning body such as a diaphragm which is separated from the float chamber 4 and divides the inside into a starting fuel pump chamber 21 and an atmospheric chamber 22. Specifically, the starting fuel pump chamber 21 is separated from the floating chamber 4 by the partitioning body 20 and the float. The atmospheric chamber 22 is formed by the concave portion of the chamber body 3 and is formed by the partition body 20 and the cover 23. Note that J is an air hole that communicates the air chamber 22 with the atmosphere.

The following passages are opened in this starting fuel pump chamber 21. That is, reference numeral 24 is a starting fuel inflow path which is provided with a suction side check valve 25 inside and communicates with a constant liquid level below the float chamber 4. A suction valve seat 26 is formed correspondingly, and the suction side check valve 25 is pressed against the suction valve seat 26 by a spring 27.

On the 2nd, the - end opens approximately in the center of the starting fuel pump chamber 21, and the other end is closer to the engine than the throttle valve 12 (left side in the figure).
This is a starting fuel discharge passage that opens into the intake passage 2, and a discharge side advance IF valve 31 that closes the discharge valve seat 29 and the discharge valve seat 28 by being pressed by a spring 30 is disposed in the starting fuel discharge passage. Ru.

Further, a valve seat 32 is formed at the opening end of the starting fuel discharge passage to the starting fuel pump chamber 21 .

Further, 33 is an on-off valve part provided integrally with the partition body 20, and this on-off valve part 33 is arranged corresponding to the valve seat 32 at the end of the starting fuel discharge passage 28, and this valve seat 32 is connected to the partition body. The starting fuel discharge passage 28 is opened and closed according to the movement of the starting fuel discharge passage 20 . Further, an operating rod 34 is integrally arranged in the partitioning body 20, and by moving this operating rod 34, the partitioning body 20 and the on-off valve section 33 are moved synchronously. N
is the first state (first state) in which the operating rod 34 (including the partition body 20 and the on-off valve part 33) is fully pressed toward the starting fuel pump chamber 21 side.
the state shown in the figure), and the second state of full tension towards the atmospheric chamber 22 (
This is an intermediate position regulating member for holding the operating rod 34 at an approximately midpoint between the state shown in FIG. A ball 35 that applies a pressing force perpendicularly to the operating rod 34 with elastic force to the groove 34A when operating to the intermediate position.
and a spring 36.

Further, 37 is contracted in the atmospheric chamber 22 and has one end connected to the cover 23.
The other end is a spring that is locked to the partition body 20 and presses the partition body 20 toward the starting fuel pump chamber 21 side.

Incidentally, when operating the intermediate position regulating member N described above, the pressing force exerted by the ball 35 by the spring 36 against the groove 34A of the operating rod 34 in a direction perpendicular to the longitudinal axis direction Y-Y of the operating rod 34 is This is greater than the pressing force of the spring 37 in the longitudinal axis direction Y-Y of the operating rod 34 when the operating rod 34 is in the intermediate position, and thereby the operating rod 34 can be held at the intermediate position.

Next, its effect will be explained.

First, the case where the engine atmosphere temperature and the engine temperature are high will be explained. Since the temperature is high, there is no need to supply the air-fuel mixture to the engine.

The starting device is therefore kept inactive. This state is shown in FIG. 1, in which the partition body 20 is
The opening/closing valve portion 33 provided integrally with the partition body 20 is pressed toward the starting fuel pump chamber 21 side by the starting fuel pump chamber 2! of the starting fuel discharge passage 28. The valve seat 32 located at the opening end to the side is closed, and the starting fuel is not supplied from the starting fuel discharge passage 28 into the intake passage 2, and the fuel at the engine temperature is mainly used. It is supplied to the intake pipe from the nozzle lO and the low-velocity nozzle hole (not shown) to satisfy starting.

Next, regarding starting in a state where the engine ambient temperature is low, before starting the first engine, first, the operating rod 34 is pulled all the way to the left in the figure against the spring force of the spring 37. clearly shown in the figure. By this operation, the partition body 20 and the on-off valve section 33 are also moved to the left in synchronization with the operating rod 34, and the on-off valve section 33 is moved toward the valve seat 3.
2 is opened, and the volume of the starting fuel pump chamber 21 is increased.

According to this, the suction side check valve 25 opens the suction valve seat 26, and the discharge side reverse ratio valve 31 closes the discharge valve seat 29.

Therefore, by such an operation, the fuel stored in the float chamber 4 is sucked into the starting fuel pump chamber 21.

Next, the leftward pulling force on the operating rod 34 is released. According to this, the operating rod 34 is moved toward the starting fuel pump chamber 21 side (as shown in the figure) by the spring force of the spring 37.
(to the right), and the operating rod 34 stops when the groove 34A engages with the ball 35 serving as the intermediate position regulating member N. (This state is shown in FIG. 3.) The reason why the operating rod 34 stops at the intermediate position is that the ball 44 acts perpendicularly to the tension of the spring 37 in the longitudinal axis direction Y-Y of the operating rod 34. This can be achieved by appropriately increasing the pressing force of the spring 3G.

When the operating rod 34 is moved to the intermediate position, the starting fuel pump chamber 21 is compressed and the chamber volume is reduced.
The discharge side check valve 31 opens the discharge valve seat 29, and starting fuel is injected and supplied from the starting fuel discharge passage 28 into the intake passage 2, thereby making it possible to prepare for the first and complete explosion of the engine, and performing such operations. After the process of pulling the rod 34 to the left all at once, and the return process of releasing the attractive force on the operating rod to return it to the intermediate position, a cranking operation for starting the engine begins.

Then, since the fuel in the starting fuel pump chamber 21 has already been injected into the intake pipe from the starting fuel discharge passage 28, a sufficiently thick air-fuel mixture can be supplied to the engine and the engine's first explosion.
You can definitely get a complete blast.

When the engine enters a warm-up state after a complete explosion, the operating rod 34 is held at an intermediate position and the valve seat 32 is held open by the on-off valve section 33, so that the engine The negative pressure acts on the discharge side advance +h valve 28 from the startup fuel discharge passage 28, opens the discharge side advance 1hi valve 31 from the discharge valve seat 29 against the spring force of the spring 30, and the inside of the startup fuel pump chamber 21 is opened. This fuel is supplied from the starting fuel discharge passage 28 to the intake passage 2 to satisfy warm-up operation.

Although the warm-up time varies depending on the performance of the engine and the ambient temperature, the opening/closing valve section 33 holds the valve seat 32 open at the intermediate position due to the intermediate position regulating member N of the operating rod 34, so the starting fuel pump chamber 21 from the starting fuel discharge passage 28, the suction side stop valve 25 opens the suction valve seat 26 and the fuel in the float chamber 4 can be sequentially supplied, so there is no problem. Never.

Next, when the warm-up of the engine is completed, the operating rod 34 is returned from the intermediate opening state shown in FIG. 3 to the original position shown in FIG. 1. According to this, since the opening/closing valve section 33 closes the valve seat 32, the starting fuel discharge passage 2 is discharged from the starting fuel pump chamber 21.
No fuel will leak to 8.

Further, during operation of one engine, the negative pressure in the intake passage 2 acts on the starting fuel discharge passage 28, and the discharge side advance 1-hi valve 31 is opened from the discharge valve seat 29 against the spring force of the spring 30. However, even if this starting fuel discharge passage 28 were to open, this negative pressure would immediately act on the lower part of the on-off valve section 33 and press the on-off valve section 33 toward the valve seat 32. On the other hand, since the opening/closing valve part 33 is pressed by the spring 37 toward the closed side of the valve seat 32, the starting fuel discharge passage 28 is kept completely closed, and unnecessary fuel is not sucked into the intake passage 2, and the engine It does not interfere with normal operation.

〔Effect of the invention〕

As described above, the carburetor starting device according to the present invention has the following effects.

■Especially for the first time when starting in a state where the engine atmosphere temperature is low,
At the time of a complete explosion, the desired starting fuel suitable for the initial and complete explosion of the engine is injected directly into the intake duct from the starting fuel discharge passage without relying on the negative pressure in the intake duct for the fuel in the starting fuel pump chamber, resulting in a reliable engine. You can get a start.

(2) When the engine is warmed up, starting fuel is automatically discharged from the starting fuel discharge passage into the intake passage due to the negative pressure generated in the intake pipe, thereby improving warm-up performance.

■When starting the engine, pull the operating lever toward the atmospheric chamber, then release the pulling force to automatically place the operating lever in the intermediate position and start the engine.

The starting fuel necessary for a complete explosion can be supplied, while the engine can be warmed up with the control rod in the intermediate position, and the control rod can be started at the end of warm-up. All you have to do is push it toward the fuel pump chamber and return it to its original position, making it extremely easy to operate and requires no skill at all to start, making it especially useful as a starting device for outboard motors and general-purpose engines. suitable.

■The amount of starting fuel injected during startup is always determined by the spring force of the spring that presses the operating rod toward the starting fuel pump chamber, so the speed with which the operating rod presses against the starting fuel pump chamber changes. Since a predetermined starting fuel is always supplied to the engine regardless of the operator's will, the engine can be started reliably and with good performance.

■Furthermore, while the engine is running, the negative pressure generated in the intake passage can be completely shut off by the on-off valve and valve seat of the compartment, so there is no negative pressure in the compartment outside the on-off valve. It is possible to provide a carburetor starting device that is stable over a long period of time because the durability of the partition body is significantly improved when the partition body is made of an elastic rubber material such as a diaphragm. It is something.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the starting fuel discharge passage of the carburetor starting device according to the present invention in a closed state, and FIG. 2 shows the operating rod in FIG. 1 pulled all the way toward the atmospheric chamber. FIG. 3 is a vertical sectional view of the main part showing a state in which the operating rod has been returned to an intermediate position from the state shown in FIG. 2.

Claims (2)

[Claims] (1) The float chamber main body 3 is arranged on the side of the carburetor main body 1 through which the intake passage 2 passes, and the float chamber main body 3
In a vaporizer in which a float chamber 4 is formed in which a constant liquid level can be stored inside;
The starting fuel pump chamber 21 is divided into a suction side check valve 25 inside, a starting fuel inflow passage 24 connected to a constant liquid level below the float chamber 4, and a discharge side check valve 25 inside. The partition body 20, which opens the starting fuel discharge passage 28 in which the stop valve 31 is disposed, and is further pressed toward the starting fuel pump chamber 21 by a spring 37, has an on-off valve section that can control opening and closing of the starting fuel discharge passage. 33 and an operating rod 34 that can apply a pump operating force to the partition body 20, and the operation rod has a valve that closes the starting fuel discharge passage 28 with the opening/closing valve portion 33 of the partition body 20. An intermediate position regulating member N is provided that can hold the partition body 20 at a substantially intermediate position between the first state and the second state in which the partition body 20 is pulled toward the atmospheric chamber 22, and when the attractive force on the operating rod 34 is released from the second state, the spring Due to the spring force of 37, the partition body 20
A starting device for a carburetor that automatically returns the pump to a substantially intermediate position and discharges the fuel in the starting fuel pump chamber 21 through the starting fuel discharge passage 28. (2) The intermediate opening degree regulating member N is elastically pressed by the groove 34A provided in a part of the operating rod 34, and the spring 36 extends in the longitudinal axis direction Y-Y of the operating rod 34. and a ball 35 that holds the operating rod in a fixed position by overcoming the urging force.
Starting device for the carburetor described in Section 1.