JPH0823337B2 - Vaporizer starter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vaporizer for controlling the concentration and amount of an air-fuel mixture supplied to an engine, and more particularly to a vaporizer for supplying a rich air-fuel mixture when starting an engine. Related to the starting device.

[Conventional technology]

2. Description of the Related Art A conventional carburetor starter for a two-cycle engine that is generally used in the past is a so-called choke in which a choke valve is arranged in the intake passage of the carburetor to keep the intake passage in a fully closed state when the engine is started. Type and a throttle valve arranged in the intake passage are connected to each other by a starting passage, and a starter opening / closing valve is arranged in the starting passage so that the starting passage is kept open by the starter opening / closing valve when the engine is started. There is a so-called starter type.

[Problems to be solved by the invention]

 Such a conventional starting device has the following problems.

That is, according to the former, when the engine is cranked by closing the choke valve at the time of starting, the intake passage negative pressure generated by this cranking is increased by the choke effect of the choke valve, and the low-speed injection hole opened into the intake passage. In this configuration, the negative pressure of the intake passage acts on the injection holes of the main nozzle and the like to suck the fuel from the injection holes and supply the starting fuel to the engine. The fuel system or the main fuel system leading to the main nozzle is set so as to conform to the low-speed operation state of the engine, or the medium and high-speed operation states, respectively. In order to make adjustments, a lot of time is spent on setting work for the adjustment.

That is, when the low-speed fuel system or the main fuel system that has been set once is changed to improve the starting performance, the low-speed fuel system and the main fuel system must be tested again for confirmation.

According to the latter, since the low-speed fuel system and the main fuel system have a start passage as a completely separate system, there is no connection between the low-speed fuel system and the main fuel system as in the former, and the setting work is easy, but the engine When the throttle valve is opened at the time of starting, it is difficult to obtain a high intake passage negative pressure in the intake passage, so that the starting fuel cannot be sucked out and the startability may be deteriorated.

[Means for solving problems]

In view of the above problems, the carburetor starting device according to the present invention is to provide the above-mentioned device having good startability that can easily perform setting work for improving the startability and can supply optimum starting fuel, In order to achieve the above-mentioned object, the float chamber main body is arranged on the side of the carburetor main body through which the intake passage penetrates, and the carburetor main body and the float chamber main body form a float chamber in which a constant liquid surface is stored. In the carburetor, a starter fuel storage chamber provided separately from the float chamber, a fuel passage connecting the lower part of the starter fuel storage chamber and a certain liquid level below the floater chamber, an upper part of the starter fuel storage chamber and the atmosphere are connected. A communicating air passage, a starting fuel pump chamber which is provided on one side of the partition body separately from the starting fuel storage chamber, and a pressure receiving chamber which is formed on the other side of the partition body and into which pulsating pressure generated in the engine is introduced. And a suction side check valve inside, and one end is Starting fuel inflow passage opening to the fuel pump chamber and the other end opening to the starting fuel storage chamber, and a discharge-side check valve inside, and the starting fuel discharge passage opening to the starting fuel pump chamber A starting fuel control passage communicating with the fuel discharge passage, a starting air passage communicating with the atmosphere, a starting mixture passage communicating with an intake pipe on the engine side of the throttle valve or a crankcase of the engine, and the starting fuel control. A starting device for a carburetor is configured by a control valve body that changes the effective passage areas of the passage, the starting air passage, and the starting mixture passage.

[Action]

When the engine is cold-started, the control valve element is first actuated to keep the starting fuel control passage, the starting air passage, and the starting mixture passage open, and then the engine and the cranking operation are started. The cranking operation causes the starting fuel pump chamber to pump the fuel in the starting fuel storage chamber, and the fuel pumped from the starting fuel pump chamber is injected from the starting fuel discharge passage into the starting fuel control passage.

The amount of the starting fuel injected into the starting fuel control passage is controlled by the control valve body, and is mixed with the air flowing in from the starting air passage to form a starting air-fuel mixture. It is supplied to the crankcase, thus satisfying the starting of the engine.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

1, an intake passage 2 penetrates the inside, and a float chamber main body 3 is disposed on a side portion of the vaporizer main body 1, and a float chamber 4 is formed by the lower concave portion of the vaporizer main body 1 and the float chamber main body 3. You. 5
Is a valve seat that is connected to the fuel inlet H and opens in the float chamber 4. A float valve 6 is movably arranged in correspondence with the valve seat 5, and the float valve 6 is located in the float chamber 4. The float 9 is disposed so as to correspond to the float arm 7 of the float 9, which is rotatably supported by the pin 8 by the float arm 7. And float 9
The float arm 7 is rotated by rotating the pin 8 and the float valve 6 controls the opening and closing of the valve seat 5.

Further, 10 is a main nozzle as a main fuel system, the tip of which is projected and opened in the intake passage 2 and the other end is the main fuel jet which is formed below a certain liquid level formed in the float chamber 4. 11
Connected to. Reference numeral 12 denotes a throttle valve for controlling the opening and closing of the intake passage 2.

The above structure is a conventionally known technique, and the carburetor starter according to the present invention has the following structure in order to achieve the above object. That is, 20 is a starting fuel storage chamber, which is formed on the side of the carburetor body 1 and independently of the float chamber 4. (It does not necessarily have to be integrated with the carburetor body 1 and the float chamber body 3) Then, the bottom portion of the starter fuel storage chamber 20 is connected to a fixed lower liquid level in the float chamber 4 via the fuel passage 21, and The upper part is connected to the atmosphere via the air passage 22, and in the present embodiment, it is connected to the atmosphere chamber K above the constant liquid level in the float chamber 4.

Therefore, the fuel in the floating chamber 4 is stored in the starting fuel storage chamber 20 through the fuel passage 21. This reservoir is a floating chamber 4
It becomes the same as the constant liquid level height XX in the inside.

Reference numeral 23 denotes a partition body such as a diaphragm which is separated from the starting fuel storage chamber 20 and further divides the inside into a starting fuel pump chamber 24 and a pressure receiving chamber 25. Specifically, the starting fuel pump chamber 24 is a partition body 23 and a float. The pressure receiving chamber 25 is formed by the concave portion of the chamber body 3.
Is formed by the partition body 23 and the cover 26.

The following paths are opened in the starting fuel pump chamber 24. That is, 27 is provided with a suction side check valve 28 inside,
A starting fuel inflow passage that connects the starting fuel pump chamber 24 and the liquid level below the starting fuel storage chamber 20, and an intake valve seat 29 corresponding to the intake side check valve 28 is formed in the starting fuel inflow passage. It

Reference numeral 31 denotes a start-side fuel discharge passage having a discharge-side check valve 32 disposed therein, one end of which opens into the start-up fuel pump chamber 24. The start-up fuel discharge passage has a discharge corresponding to the discharge-side check valve 32. Valve seat 3
4, and a spring 35 for pressing the discharge side check valve 32 against the discharge valve seat 34 is contracted.

Further, in the pressure receiving chamber 25, there is opened a pulsating pressure introducing passage 36 which is connected to a crankcase of the engine and an intake pipe (neither is shown) and which introduces the pulsating pressure generated in the operation of the engine into the pressure receiving chamber 25.

Reference numeral 40 denotes a control device main body having a cylindrical sliding hole 41 therein. A starting fuel control passage 42 connected to the starting fuel discharge passage 31 is opened at the bottom of the sliding hole 41, and the sliding hole 41 is provided.
A start air passage 43 communicating with the atmosphere and a start air-fuel mixture passage 44 communicating with an intake pipe on the engine side of the throttle valve 12 or a crankcase (not shown) of the engine from the throttle valve 12 are opened on the side of the.

Further, 45 is the starting fuel control passage 42 and the starting air passage 4
3, a control valve body that controls the passage effective area of the starting mixture passage 44 (variably controls from fully closed to fully opened in stages),
More specifically, it is formed into a cylindrical shape so as to be fitted into the sliding hole 41, and the passage effective area of the starting air passage 43 and the starting mixture passage 44 is variably controlled at the side portion of the cylinder. The effective passage area of the control passage 42 is controlled by inserting the needle valve 45 arranged on the bottom surface A of the cylindrical portion into the starting fuel control passage 42 and controlling the valve portion 46 provided on the bottom surface A.

Incidentally, 47 is a wire for pulling the control valve body 45, and 48 is a spring for returning the control valve body 45 to the original position.

 Next, the operation will be described.

First, the case where the engine atmosphere temperature and the engine temperature are high will be described. The control valve body 45 does not perform any operation, and the wire 47 is in the inoperative state. According to this, the starting air passage 43 and the starting mixture passage 44 are closed on the outer peripheral side of the control valve body 45, while the starting fuel control passage 42 is also closed by the valve portion 46.
Is held closed at.

Therefore, in such a state, when a cranking operation is applied to the engine to start the engine, the pulsating pressure generated in the crankcase is introduced into the pressure receiving chamber 25 through the pulsating pressure introducing passage 36 and reciprocates in the partition 23. As described above, the starting fuel control passage connected to the starting fuel discharge passage 31 is provided.
Since the control valve body 45 blocks the 42, the starting air passage 43, and the starting mixture passage 44, the fuel is not discharged from the starting fuel pump chamber 24 into the carburetor or the crankcase of the engine, and the main nozzle is normally used. The engine can be started by fuel from 10 and a low speed fuel system (not shown).

Next, regarding the start in a state where the engine atmosphere temperature is low, prior to the cranking start operation of the engine, first, the wire 47 is pulled to pull up the control valve element 45 upward, whereby the start fuel control passage 42, The starting air passage 43 and the starting mixture passage 44 are kept open.

After the operation of the control valve element 45, the cranking operation of the engine is performed. According to this, similarly to the above, the pulsating pressure generated in the crankcase is transmitted to the pressure receiving chamber 25 through the pulsating pressure introducing passage 36.
The fuel in the starting fuel storage chamber 20 is sucked through the starting fuel inflow passage 27 and injected into the starting fuel control passage 42 through the starting fuel discharge passage 31. To be done.

The amount of the injected starting fuel is controlled by the needle valve 45, and is mixed with the air flowing in from the starting air passage 43 to form a starting air-fuel mixture which passes through the starting air-fuel mixture passage 44 into the intake pipe or the crankcase. Is directly injected and supplied to.

The starting fuel is sufficiently rich because the fuel previously stored in the starting fuel storage chamber 20 can be injected at once, and the starting fuel control passage 42, the starting air passage 43, and the starting mixture passage 44 are opened in a sufficiently large area. Since it is possible to form and supply a large amount of air-fuel mixture, the initial and complete explosions of the engine can be reliably performed.

When the starting fuel injected from the starting fuel discharge passage is directly supplied to the crankcase of the engine, the fuel supply speed to the combustion chamber of the engine is increased, so the startability is further improved.

Next, when the engine is completely detonated and enters warm-up operation, at this time, most of the fuel already stored in the starting fuel storage chamber 20 is consumed, and the starting fuel and air passage 22 limited in the fuel passage 21 are consumed. The air-fuel mixture mixed with the restricted air is supplied from the starting fuel discharge passage 31 through the starting fuel pump chamber 24, while the driver senses the transition to warm-up operation of the engine. Since the wire 47 is loosened and the control valve body 45 is appropriately returned to reduce the effective passage areas of the starting fuel control passage 42, the starting air passage 43, and the starting mixture passage 44, (when the control valve body 45 moves downward, , The effective passage area of the starting fuel control passage 42 is reduced by the needle valve J, and the effective passage area of the starting air passage 43 and the starting mixture passage 44 is reduced on the outer peripheral side of the control valve body 45.) It is possible to supply a mixture that has been diluted and whose amount has been reduced. It is possible to obtain.

By arranging the jets in the fuel passage 21 and the air passage 22, respectively, the flow rate control during the warm-up operation can be performed more easily.

When the warm-up operation is completed, the driver completely loosens the wire 47 to return the control valve element 45 to the original position (the state shown in FIG. 1). As described above, the starting fuel control passage 42,
The starting air-fuel mixture passage 44 and the starting air passage 43 are held in a fully closed state by the control valve body 45.

Therefore, the injection of the starting air-fuel mixture from the starting air-fuel mixture passage 44 is stopped, and the normal operation can be maintained by receiving the fuel supplied from the normal carburetor.

Further, in the structure shown in FIG. 2, instead of the manual operation of the control valve body 45 by the wire 47 in FIG. 1, a heat sensitive member 50 such as wax is arranged corresponding to the control valve body 45, and the engine atmosphere Controls the operating force that the heat sensitive member 50 operates by sensing the temperature.
The driving force of 45 is used, and more specifically, the heat-sensitive member 50 contracts when the engine ambient temperature is low, causing the pressing member 51 to contract.
The convex dimension H with respect to the control valve element 45 becomes small, and the convex dimension H becomes large due to expansion at a high engine atmosphere temperature.

Therefore, when the engine ambient temperature is low, the control valve body
45 keeps the starting fuel control passage 42, the starting air passage 43, the starting mixture passage 44, and the passage effective area large, and automatically reduces the respective passage effective areas as the temperature rises. Hold completely occluded.

A heater and a heater (PTC) having a positive temperature characteristic are used to control the operation response of the heat sensitive member 5.
You may arrange | position corresponding to 0.

〔The invention's effect〕

When the engine is started, the control valve element is opened to inject fuel from the start fuel pump chamber into the start fuel control passage in synchronization with cranking of the engine, and the control valve element changes the injection amount. By controlling again, the air flowing in from the starting air passage is mixed to form a starting mixture, which is injected and supplied from the starting mixture passage to the intake pipe on the engine side or the crankcase from the throttle valve, so that the ignitability of the engine is reduced. It is possible to improve the startability.

Also, since the increased amount of starting air-fuel mixture could be supplied without operating the throttle valve at all, it was possible to achieve a fast idling operation in which the engine speed at starting was raised above the idling speed, thus stabilizing the rotation at starting. It was able to improve the toughness against.

Even if the driver opens the throttle valve, this starting device does not suck the starting air-fuel mixture due to the negative pressure in the intake passage, so the starting air-fuel mixture can be injected and supplied without being affected by it. Can be improved.

Further, since the concentration and amount of the starting air-fuel mixture are controlled by the system of the air passage and the fuel passage, and the system of the starting fuel control passage by the control valve body, the starting air passage, the starting air-fuel mixture passage, the dual system. Optimal setting can be easily achieved in a short time at the time of starting.

Further, since the air is positively mixed with the injection start fuel from the start air passage, the atomization property of the fuel in the intake pipe and the crankcase can be improved, and particularly the low temperature startability can be improved.

Furthermore, if the control valve element is controlled by the heat sensitive member,
Since the operation at the time of starting is fully automatic, the starting operability can be made easy and the starting operation by the driver can be made easy and reliable.

Further, particularly in a multi-cylinder engine in which a multi-vaporizer is used to supply the air-fuel mixture, and since the starting air-fuel mixture supplied from the starting air-fuel mixture passage may be simply distributed, the starting system of the engine as a whole is It can be easily summarized.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a carburetor starter according to the present invention, and FIG. 2 is a vertical cross-sectional view of an essential part showing another example. 1 ... Vaporizer body, 4 ... Float chamber, 20 ... Starting fuel storage chamber, 21 ... Fuel passage, 22 ... Air passage, 23 ... Compartment, 24 ... Starting fuel pump chamber, 25 ... Pressure receiving chamber, 27 …… Starting fuel inflow passage, 31 …… Starting fuel discharge passage, 36 …… Pulsating pressure introducing passage, 42 …… Starting fuel control passage, 43 …… Starting air passage 44 …… Starting mixture passage, 45 ...... Control valve body, 47 ...... Wire, 50 ...... Heat sensitive member.

Claims (2)

[Claims] 1. A vaporizer in which a float chamber main body is arranged on a side portion of a vaporizer main body having an intake passage penetrating the interior thereof, and a float chamber for storing a constant liquid level therein is formed by the vaporizer main body and the float chamber main body. In the container, a starting fuel storage chamber provided separately from the floating chamber, a fuel passage connecting the lower part of the starting fuel storage chamber and a certain liquid level below the floating chamber, and connecting the upper part of the starting fuel storage chamber to the atmosphere. An air passage, a starting fuel pump chamber provided separately from the starting fuel storage chamber on one side of the partition body, and a pressure receiving chamber formed on the other side of the partition body for introducing pulsating pressure generated in the engine, The intake side check valve is arranged inside, the one end is opened to the starting fuel pump chamber, the other end is opened to the starting fuel storage chamber, and the discharge side check valve is arranged inside to start. Starting fuel discharge passage opened to the fuel pump chamber and starting connected to the starting fuel discharge passage A fuel control passage, a starting air passage communicating with the atmosphere, a starting mixture passage communicating with an intake pipe on the engine side of the throttle valve or a crankcase of the engine, the starting fuel control passage, a starting air passage, a starting mixture. A carburetor starting device comprising: an air passage; and a control body that changes an effective area of the air passage. 2. A vaporizer in which a float chamber main body is disposed on a side portion of a vaporizer main body through which an intake passage penetrates, and a float chamber for storing a constant liquid surface is formed inside by the vaporizer main body and the float chamber main body. In the container, a starting fuel storage chamber provided separately from the floating chamber, a fuel passage connecting the lower part of the starting fuel storage chamber and a certain liquid level below the floating chamber, and connecting the upper part of the starting fuel storage chamber to the atmosphere. An air passage, a starting fuel pump chamber provided separately from the starting fuel storage chamber on one side of the partition body, and a pressure receiving chamber formed on the other side of the partition body for introducing pulsating pressure generated in the engine, A suction side check valve is placed inside, a start fuel reservoir is opened at one end to the start fuel pump chamber and the other end is opened to the start fuel storage chamber, and a discharge check valve is placed inside to start the engine. Starting fuel discharge passage opened to the fuel pump chamber and starting connected to the starting fuel discharge passage A fuel control passage, a starting air passage communicating with the atmosphere, a starting mixture passage communicating with the intake pipe on the engine side of the throttle valve or the crankcase of the engine, the starting fuel control passage, the starting air passage, and the starting mixture. A starter for a carburetor comprising: a control valve body that changes an effective passage area of an air passage; and a heat-sensitive member that applies a driving operation force to the control valve body according to a change in engine ambient temperature.