JPS6032364Y2 - vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor for an engine that uses, for example, alcohol as a regular fuel and uses, for example, gasoline as a starting fuel.

Conventionally, in this type of carburetor, an intake passage having a venturi part is provided with a throttle valve located downstream of the venturi part, and a regular fuel nozzle such as a primary nozzle that opens into the intake passage is connected to the fuel in the float chamber. A main fuel supply hole is opened in the upper part of the float chamber and communicates with the main fuel tank which stores normal fuel and which communicates with the inside of the cup body, which is disposed below the oil level with its opening facing downward, and which also stores starting fuel. An auxiliary fuel supply hole that communicates with an auxiliary fuel tank to be used via a starting fuel valve is opened in the cup body, and starting fuel is injected into the cup body by opening the starting fuel valve at the time of especially cold starting of the engine. It is known that the regular fuel in the cup body is replaced with starting fuel, and this is injected into the intake passage through the regular nozzle.
(See Publication No. 9).

However, in such a device, a relatively large amount of starting fuel is injected into the cup body so as not to be diluted with the service fuel, and if the starting fuel is diluted with the service fuel,
The initial combustion of the engine is delayed, making it difficult to start.

Furthermore, since the amount of starting fuel supplied is adjusted by the opening time of the starting fuel valve, there are disadvantages in that the operation must rely on feeling and requires skill.

In this invention, a certain percentage of the specified amount of starting fuel that is supplied from the metering pump to the cup body side is injected into the cup body by directly injecting the fuel into the intake passage through the starting nozzle to promote the initial explosion of the engine. Even if the starting fuel is diluted to some extent with the regular fuel, it is possible to achieve a complete explosion of the engine with this fuel, thereby making it possible to reliably start the engine with a small amount of starting fuel without requiring any skill. It is an object of the present invention to provide the vaporizer that can perform the following steps.

In order to achieve the above object, the present invention includes a metering pump capable of discharging a specified amount of starting fuel in the fuel passage connected to the auxiliary fuel tank, and a starting nozzle opened in the intake path downstream of the throttle valve. and communicating the nozzle with a fuel passage between the metering pump and the auxiliary fuel supply hole through the starting fuel passage;
a first discharge valve and an orifice in series with the starting fuel passage;
Further, the fuel injection device is characterized in that each of the auxiliary fuel supply holes is provided with a second discharge valve having a higher opening pressure than the first discharge valve.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a carburetor main body, through which an intake passage 2 horizontally passes through the central part, and a container 4 defining a float chamber 3 at the bottom thereof. are joined.

The intake path 2 is provided with a choke valve 5 on the upstream side (right side in the figure) and a throttle valve 6 on the downstream side of the central venturi portion 2a, and a starting nozzle 7 located slightly downstream of the throttle valve 6. A bypass port 8 is opened at a position close to the throttle valve 6, a primary nozzle 9 is opened at an intermediate portion between the throttle valve 6 and the venturi section 2a, and a secondary nozzle 10 is opened at the venturi section 2a.

The primary nozzle 9 and the secondary nozzle 10 communicate with the float chamber 3 via a primary jet 11 and a secondary jet 12, respectively.

A low-speed fuel passage 13 branches from between the primary nozzle 9 and the primary jet 11 and is connected to the bypass port 8.

A slow jet 14 is inserted into the low speed fuel passage 13.

A main fuel supply hole 15 is opened on the upper surface of the float chamber 3, and a well-known float valve 16 is installed in the opening of the main fuel supply hole 15. The opening/closing of the main fuel supply hole 15 is controlled to maintain the fuel oil level within the main fuel supply hole 15 at a specified level.

A fuel passage 18 connected to the main fuel tank Tm is connected to the main fuel supply hole 15, and in the middle of this passage 18 is a well-known cock 19 having three control positions: ON, OFF, and RESERVE.
is interposed.

The main fuel tank Tm stores alcohol fuel A for regular use.

Further, in the float chamber 3, a cup body 20 with an opening facing downward is fixed to the lowest end of the carburetor body 1 using the primary and secondary jets 11, 12 screwed thereon.

This cup body 20 has an earthen wall with two steps, upper and lower, with a primary jet 11 opening on the inner surface of the upper step 20a, and a secondary jet 1 opening on the inner surface of the lower step 20b.
2 opens.

An auxiliary fuel supply hole 21 that opens into the cup body 20 is formed in the bottom wall of the container 4, and a fuel passage 22 connected to the auxiliary fuel tank Ts is connected to this, and a metering pump 2 is connected to the fuel passage 22 in the middle of the hole.
3 is interposed.

The auxiliary fuel tank Ts stores starting gasoline fuel G.

Fuel passage 22 between auxiliary fuel supply hole 21 and metering pump 23
A starting fuel passage 37 branches off from the starting fuel passage 37, which is connected to the starting nozzle 7.

The metering pump 23 has a pump body 24, the inside of which is connected to the pump chamber 2 by a diaphragm 26 connected to an operating rod 25.
7 and an atmospheric chamber 28, and a return spring 29 that urges the diaphragm 26 toward the pump chamber 27 is contracted in the atmospheric chamber 28.

The operating rod 25 is slidably supported by a boss 24a formed on the right end wall of the pump body 24, and its traction stroke is regulated.

A pump piston 26' and a valve body 30, which operate together with a diaphragm 26 in a pump chamber 27, are connected to the operating rod 25, and a valve seat 31 that cooperates with the valve body 30 is formed on the left end wall of the pump chamber 27.

An inflow hole 32 and an outflow hole 33 are opened in the inner wall of the pump chamber 27 so as to sandwich the valve seat 31, and the pump chamber 27 is connected to the upstream side of the fuel passage 22 through the inflow hole 32 and to the outflow hole 33. The two are connected to the downstream side through the same.

Suction valve 35 and first discharge valve 36 associated with metering pump 23
The first and second discharge valves 36□ are provided in the inflow hole 32, the auxiliary fuel supply hole 21, and the starting fuel passage 37, respectively. The opening pressure of the first discharge valve 36□ is set lower than that of the second discharge valve 36□.

After opening the first discharge valve 361, the second discharge valve 36□
An orifice 39 is formed in the starting nozzle 7 to provide a predetermined opening pressure.

This orifice 39 can also be replaced by restricting the nozzle hole of the starting nozzle 7.

The suction valve 35 is configured to be of a normally open type.

Next, to explain the operation of this embodiment, when starting the engine in cold weather, first operate the cock 19 to make the fuel passage 18 conductive, and the alcohol fuel A in the main fuel tank Tm is transferred into the float chamber. meet the specified level.

Next, when the operating rod 25 of the metering pump 23 is pulled, the valve body 30 separates from the valve body 31 and opens the inflow hole 32.
The pressure inside the pump chamber 27 is reduced by the right movement of the diaphragm 26 and the pump piston 26', so the auxiliary fuel tank T
s of gasoline fuel G passes through the inflow hole 32 and enters the pump chamber 27.
The prescribed amount is inhaled.

Therefore, when the operating rod 25 is released, the diaphragm 26 moves to the left by the elastic force of the return spring 29 to pressurize the inside of the pump chamber 27, and as the pressure increases, the suction valve 35 is first closed and the valve opening pressure is increased. The first discharge valve 36□ with a low opening pressure is opened, and then the pressure on the upstream side thereof is increased by the orifice 39, and the second discharge valve 36□ with a high opening pressure is opened, so that the gasoline fuel G in the pump chamber 27 is initially starting fuel passage 3
7, the fuel is injected into the intake passage 2 from the starting nozzle 7 while being metered by the orifice 39, and then into the auxiliary fuel supply hole 2.
It is also injected into the cup body 20 from 1.

Then, when the operating rod 25 reaches its leftward limit of movement and the valve body 30 closes the inflow hole 32, the discharge of the specified amount of gasoline fuel G ends.

In this way, the specified amount of gasoline fuel G discharged from the metering pump 23 is distributed between the starting nozzle 7 and the cup body 2 at a constant rate.
It is distributed between 0 and 0.

Therefore, in the cup body 20, due to the injection pressure of the gasoline fuel G and the difference in specific gravity between the two fuels A and G, the cup body 20
A part of the alcohol fuel A that occupied the inside of the cup body 20
The oil is pushed out from the opening at the bottom of the float chamber 3, raising the oil level in the float chamber 3 above the specified level.

As a result, relatively pure gasoline fuel G is concentrated at the top of the cup body 20, and the concentration of gasoline fuel G in alcohol fuel A decreases as it goes downward.

In this state, if the choke valve 5 is closed and the throttle valve 6 is opened to an appropriate fast idle opening to crank the engine, the gasoline fuel G already injected from the starting nozzle 7 will be drawn into the engine's intake negative pressure. is supplied to the engine, and the engine immediately explodes for the first time, and the increased suction negative pressure acts strongly on the bypass port 8 and primary nozzle 9, and the primary jet 11 connected to them,
Since the opening is at the top of the cup body 20 where the gasoline fuel G is most concentrated, the gasoline fuel G is mainly sucked in from the primary jet 11 and ejected from the port 8 and nozzle 9 to be supplied to the engine. The engine reaches full combustion and the start is completed.

Immediately after starting, when the throttle valve 6 is opened to apply a load to the engine, the intake negative pressure of the engine acts sequentially from the primary nozzle 9 to the secondary nozzle 10 as the opening degree increases, and accordingly, the primary nozzle 9 As mentioned above, mainly gasoline fuel G is spouted from the secondary nozzle 10, and the secondary jet 12 connected thereto opens at the middle part of the cup body 20, so that the mixed fuel of gasoline and alcohol present there is spouted as a secondary jet. It is ejected via jet 12.

Therefore, although the components of the fuel supplied to the engine change as the throttle valve 6 opens, the change is gradual, so that the transition to load operation can be smoothly performed even immediately after starting.

In this way, when the fuel in the cup body 20 is consumed, the alcohol fuel A from the float chamber 3 enters the inside from below and dilutes the gasoline fuel G, until finally only the alcohol fuel A is in the cup body. 20, and the engine is operated on the regular alcohol fuel A.

Incidentally, when starting the engine, if the traction stroke of the operating rod 25 of the metering pump 23 is adjusted depending on the degree of cold,
The amount of gasoline fuel G injected into the cup body 20 can be adjusted, and the injection of gasoline fuel G is not necessary in warm conditions.

Also, for cleaning etc. inside the auxiliary fuel tank Ts,
When discharging the contents of s, remove the downstream side of the fuel passage 22 and pull the operating rod 25 to hold the valve body 30 in the open position. , the passage 22 via the inflow hole 32, the pump chamber 27 and the outflow hole 33.
leak outside.

Since the suction valve 35 is of the normally open type, the operating rod 25
No pumping operation is required.

As described above, according to the present invention, the metering pump 23 capable of discharging a specified amount of starting fuel is interposed in the fuel passage 22 connected to the auxiliary fuel tank Ts, and the starting nozzle is installed in the intake path 2 downstream of the throttle valve 6. 7 is opened and the nozzle 7 is communicated with the fuel passage 22 between the metering pump 23 and the auxiliary fuel supply hole 21 via the starting fuel passage 37, and the first discharge valve 361 and the orifice 39 are connected in series with the starting fuel passage 37. In addition, since the auxiliary fuel supply hole 21 is provided with a second discharge valve 362 having a higher opening pressure than the first discharge valve 361, the valve can be opened as long as a specified amount of starting fuel is discharged from the metering pump 23. By cooperation of the first and second discharge valves 361.36° having different pressures and the orifice 39, a prescribed amount of starting fuel is accurately distributed to the starting nozzle 7 and the cup body 20 at a constant ratio. can be used, and its distribution requires no skill at all.

Since the starting fuel ejected from the starting nozzle 7 promotes the initial explosion of the engine, the starting fuel in the cup body 20, which contains some regular fuel, can also cause a complete explosion of the engine, which results in a relatively The engine can be reliably started cold with a small amount of starting fuel.

[Brief explanation of drawings]

The drawing is a longitudinal side view showing an embodiment of the present invention. 2... Intake path, 2a... Venturi section, 3... Float chamber, 6... Throttle valve, 7
...Start nozzle, 8...Bypass port as a regular fuel nozzle, 9...Primary nozzle as a regular fuel nozzle, 10...As a regular fuel nozzle Secondary nozzle, 15...Main fuel supply hole, 20...Cup body, 21...
・Auxiliary fuel supply hole, 22...Fuel passage, 23・
...Metering pump, 361...First discharge valve, 36□...Second discharge valve, 37...Starting fuel passage, 39...・Orifice, A...
・Alcohol fuel as a regular fuel, G...
Gasoline fuel as starting fuel, Tm...main fuel tank, Ts...auxiliary fuel tank.

Claims (1)

[Scope of utility model registration request] A throttle valve 6 located downstream of the venturi portion 2a is provided in the intake path 2 having the venturi portion 2a, and a regular fuel nozzle such as a primary nozzle 9 opening into the intake path 2 is provided.
The main fuel supply hole 15, which communicates with the inside of the cup body 20 disposed below the fuel oil level in the float chamber 3 with its opening facing downward, and communicates with the main fuel tank Tm that stores fuel for regular use, is connected to the float chamber. 3. In a carburetor in which an auxiliary fuel supply hole 21 is opened in the cup body 20 and communicates with an auxiliary fuel tank Ts that stores starting fuel through a fuel passage 22, the carburetor has a specified amount of starting fuel. A metering pump 23 capable of discharging fuel is connected to the fuel passage 2 connected to the auxiliary fuel tank Ts.
2, a starting nozzle 7 is opened in the intake passage 2 downstream of the throttle valve 6, and the nozzle 7 is connected to the starting fuel passage 37.
via the metering pump 23 and the auxiliary fuel supply hole 21
A first discharge valve 36 □ and an orifice 39 are connected in series to the starting fuel passage 37 , and a first discharge valve 36 □ and an orifice 39 are connected in series to the starting fuel passage 37 , and a first discharge valve 36 □ and an orifice 39 are connected in series to the auxiliary fuel supply hole 21 . A vaporizer characterized in that two discharge valves 36□ are provided respectively.