JPS6278461A - Composite type carburetter - Google Patents

Abstract

PURPOSE:To prevent the occurrence of running-out of fuel for a very short time along with vibration of a vehicle, by a method wherein, in a composite carburetter consisting of a main carburetter for normal operation and a heavy- duty carburetter, a low volume fuel reservoir is located in a fuel passage connected to the fuel injection port of the heavy-duty carburetter. CONSTITUTION:A composite carburetter 1 consists of a normally-working carburetter 2, normally used for a time between idling running and a maximum output, and a heavy-duty carburetter 3 actuated only in a high load area. The normally-working carburetter 2 is provided on the under surface of a suction drum 2b with a float chamber 2e open to a suction passage and connected to a fuel injection port, and the opening area of the injection port is regulated by a needle valve 2f formed integrally with a pistonform throttle valve 2c. Meanwhile, the heavy-duty carburetter 3 includes a pistonform throttle valve 3d having a needle valve 3f inserted in a heavy-duty fuel injection part 3e. The float chamber 2e is communicated with a weighing cylinder 3h of the heavy-duty carburetter 3 through a fuel passage 3n, and in this case, a low volume fuel reservoir 7 is placed in the fuel passage 3n to realize a desired purpose.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite type vaporizer that functionally combines a conventional vaporizer and a high-force vaporizer. Regarding improvements omitted from the float chamber.

[Conventional technology and its problems]

Conventionally, in order to expand the operating load range of an engine, a regular carburetor that operates over a wide operating range and a high-power carburetor that operates only in a high load range were installed in the intake passage. There is. Among such composite type carburetors, there is one known in which the float chamber of the high-force carburetor is omitted and fuel is supplied from the float chamber of the regular carburetor (for example, Japanese Patent Laid-Open No. 59-20554 Public bulletin). Omitting the float chamber of the high-force carburetor in this way not only reduces the number of parts in the carburetor and makes it possible to manufacture it economically, but also allows for low-power operation when the high-force carburetor is not operating. This is extremely effective in solving the problem of unnecessary fuel consumption due to fuel flowing into the intake passage when the carburetor vibrates.

However, with this configuration, when the vehicle is used for competitions, the fuel is injected from the nozzle into the intake passage all at once due to vibrations while the high-power carburetor is operating.
The fuel supply may then be cut off for a brief moment, resulting in a drop in output.

[Object of the invention, outline of the structure]

The purpose of this invention is to eliminate the above-mentioned problems, eliminate fuel wastage during low-load operation, and eliminate as much as possible the sudden decrease in output that tends to occur during high-power operation. In a device in which the interposed carburetor is composed of a regular main carburetor and a high-power carburetor used for high-load operation, and a float chamber communicating with the fuel nozzle of the main carburetor is communicated with the fuel nozzle of the high-power carburetor. , a special feature lies in the fact that a small-capacity fuel reservoir is attached to the fuel passage leading to the fuel nozzle of the high-power carburetor.

[Operation] Even if fuel may be temporarily ejected from the fuel nozzle of the high-power carburetor during high-power operation, fuel will be immediately replenished from the fuel reservoir of the high-power carburetor near the fuel nozzle, and the operation will continue. can supply fuel to the intake passage.

〔Example〕

Hereinafter, the present invention will be explained with reference to the illustrated embodiment. In the figure, 1 is a composite carburetor according to the present invention, and a regular carburetor 2 is commonly used from idle-link operation to maximum output.
and a high-force carburetor 3 that operates only in a high load range.

As shown in FIG. 2, the regular carburetor 2 includes an intake cylinder 2b forming an intake passage 2a, a piston-shaped throttle valve 2c that appears on the upper surface of the intake passage 2a, and a fuel nozzle 2d on the lower surface of the intake cylinder 2b. It has a float chamber 2e that communicates with the float chamber 2e. Throttle valve 2C
is opened and closed by an operator (not shown). Reference numeral 2f designates a needle valve protruding from the lower surface of the throttle valve 2C, the tip of which is inserted into the fuel nozzle 2d, and is used to adjust the fuel flow rate to large or small levels as the throttle valve 2C moves up and down. be.

゛ As shown in Fig. 3, the high-power carburetor 3 has an intake passage 3a.
A butterfly-shaped throttle valve 3C and a piston-shaped throttle valve 3d are provided in the intake body 3b forming the intake cylinder 3b.

The butterfly-shaped throttle valve 3C of the high-power vaporizer 3 is, for example,
It is connected to the throttle valve 2C via a link and is controlled to open and close in conjunction. High-force fuel nozzle 3C is located on the lower surface of the intake passage 3a.
is opened, and a needle valve 3f protruding from the lower surface of a piston-shaped throttle valve 3d is fitted therein, similar to the regular carburetor 2.

The piston-shaped throttle valve 3d responds to the intake negative pressure on the downstream side of the butterfly-shaped throttle valve 3C, and as a result, opens and closes with a slight delay from the butterfly-shaped throttle valve 3C, thereby preventing fluctuations in the air-fuel ratio due to fuel injection delay. has been improved. The above configuration is not particularly different from the conventional configuration.

Here, the high-force vaporizer 3 is not provided with a float chamber,
This simplifies the structure and prevents fuel from flowing into the intake passage 3a due to ripples during low power operation. The high-power fuel nozzle 3e is provided at the upper end of an emulsion pipe 3j inserted into a fuel measuring tube 3h extending downward from the intake cylinder 3b. 3 is a knot for metering the maximum flow rate of fuel, which is provided in the connecting pipe 5. The measuring cylinder 3h is communicated with the inside of the float chamber 2e of the regular carburetor 2 via the connecting box 5 and the connecting pipe 6. That is, a fuel passage 3n is bored in the bottom wall constituting the float chamber 2e, going from one side to the other side and rising along the wall surface of the other side, and the connecting pipe 5 is connected to this fuel passage 3n. ing. therefore,
Even if the fuel in the float chamber 2e ripples as the engine runs or the vehicle travels, this prevents the influence from reaching the high-force carburetor 3.

7 is a small-capacity fuel reservoir υ provided in the fuel passage 3n leading to the high-power fuel nozzle 3e of the high-power carburetor 3, and the volume of 7 is 1 to 3.
It is about cc. As shown in FIGS. 3 and 4, the fuel reservoir 7 is provided on the side or below the fuel passage 3n and connected to the fuel passage 3n through a narrow passage, or as shown in FIG. It is preferable to interpose it in the middle of the passage 3n.

Next, the operation of this embodiment will be explained. When the engine is operated under high load, the throttle valve 2C of the regular carburetor 2 is opened beyond the scheduled opening, and when the engine speed increases,
The intake flow rate increases and the venturi negative pressure increases, and accordingly, the butterfly-shaped throttle valve 3d and the piston-shaped throttle valve 3d of the high-force carburetor 3 open back and forth. This further increases the engine output.

When the engine is operating at high output like this, if the vehicle vibrates greatly and suddenly due to rough roads,
Out of the fuel in the fuel passage 3n, the fuel existing near the nozzle 3e is simultaneously ejected from the high-force fuel nozzle 3e into the intake passage 3a, but at this time, a fuel reservoir 7 is attached to the fuel passage 3n. Since the fuel there immediately follows this,
Never run out of fuel.

〔Effect of the invention〕

As described above, this invention is a composite type carburetor in which a fuel reservoir with a walking capacity is attached to the fuel passage leading to the fuel nozzle of the high-power carburetor, so that the high-power carburetor can be operated at high power during high-power operation. Even if fuel is temporarily ejected from the fuel nozzle, the fuel is immediately replenished from the fuel reservoir of the high-power carburetor near the fuel nozzle, which prevents the fuel from running out, which can easily occur for a short period of time, and improves the performance of the vehicle. This has the effect of providing stable high output even when subjected to severe vibrations.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view of the carburetor, FIG. 2 is a cross-sectional view of the carburetor along the line I-■, FIG. 3 is a cross-sectional view of the carburetor, and FIGS. 6 is a sectional view of a main part showing another embodiment, and FIG. 6 is a sectional view corresponding to FIG. 4 showing a conventional example. 2...Common use vaporizer, 3...High strength vaporizer, 3
h...Fuel measuring tube, 3n...Fuel passage, 5.
... Connecting box, 6... Connecting pipe, 7... Fuel reservoir.

Claims (5)

[Claims] (1) The carburetor installed in the intake passage consists of a regular main carburetor and a high-power carburetor used for high-load operation, and the float chamber leading to the fuel nozzle of the main carburetor is used as the fuel for the high-power carburetor. A composite carburetor that communicates with a fuel nozzle, in which a small-capacity fuel reservoir is attached to a fuel passage that communicates with the fuel nozzle of the high-force carburetor. (2) A composite carburetor according to claim 1, wherein the small-capacity fuel reservoir is opened to a fuel passage leading to a fuel nozzle of the high-power carburetor. (3) The small capacity fuel reservoir is interposed in the middle of the fuel passage leading to the fuel nozzle of the high-power carburetor.
Combined vaporizer as described in section. (4) The compound carburetor according to claim 1, wherein the small capacity fuel reservoir has an internal volume of 1 to 3 cc. (5) The compound carburetor according to claim 1, wherein the fuel passage is provided with a throttle that regulates the maximum flow rate of the fuel.