JPS6133244Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a carburetor for an automobile engine,
In particular, the present invention relates to a fuel supply structure for acceleration which is incorporated in a carburetor and compensates for the air-fuel ratio during acceleration.

It is known that the air-fuel mixture becomes lean when the throttle valve is opened from the fully closed position in order to accelerate the engine in the carburetor.

For this reason, carburetors are generally equipped with an acceleration fuel pump that operates mechanically in conjunction with the depression of the accelerator pedal and injects a certain amount of fuel into the intake passage according to the opening amount of the throttle valve. This acceleration fuel pump supplies additional fuel only while the throttle valve is being opened and for a very short period of time immediately afterwards, preventing the mixture from becoming lean during that time. However, during acceleration when the throttle valve is opened from the fully closed position as described above, it is not possible to prevent the mixture from becoming lean due to the delay in the carburetor's response to the load for several seconds after the operation of the acceleration fuel pump has ended.

In view of the above problems, efforts have been made to incorporate an accumulator mechanism into the accelerator fuel pump to extend its fuel supply time, or to install a diaphragm-type auxiliary accelerator fuel pump that is operated by negative pressure in the intake pipe. ing. However, an accelerating fuel pump having an accumulator mechanism has a complicated structure, and it may not be possible to obtain the necessary fuel supply characteristics particularly at the initial stage of acceleration. In addition, in diaphragm-type auxiliary acceleration fuel pumps, there is a problem with the durability of the diaphragm that separates the working chamber into which negative pressure is introduced and the pump chamber where fuel is filled, and if the diaphragm breaks, the pump chamber The disadvantage is that a large amount of fuel is sucked into the intake manifold.

In order to prevent the mixture from becoming leaner after the additional fuel supply by the accelerator fuel pump as described above is completed during acceleration, the present invention provides an increased amount of fuel for only a short period of time during the start-up period of the carburetor. Although the overall fuel supply capacity of the carburetor is temporarily increased by additional supply of The object is to provide an acceleration fuel supply structure for a carburetor that has no moving parts.

This purpose, according to the present invention, includes an intake passage having a bench lily portion, a throttle valve that controls opening and closing of the intake passage downstream of the vent lily portion, and a liquid fuel whose liquid level is controlled to a predetermined liquid level. A fuel supply structure during acceleration of a carburetor having a float chamber for storing liquid fuel, and a main fuel supply system for supplying liquid fuel from the float chamber to a main fuel nozzle opening into the bench lily part, and the main fuel supply system is Separately, it communicates with the float chamber at a position lower than the predetermined liquid level in the float chamber through an auxiliary jet having a relatively high degree of restriction, and directly supplies liquid fuel from the float chamber through the auxiliary jet. a well that can store liquid fuel up to the same liquid level as the liquid level in the float chamber; an auxiliary fuel passageway including a pipe member opening at a lower position by a distance of 100 cm and an auxiliary fuel passage leading from the one end of the pipe member to an auxiliary fuel nozzle opening into the vent lily portion, and the predetermined degree of constriction of the auxiliary jet is When the vaporizer is operating with the throttle valve open, the liquid level in the well is not sufficient to rise above the one end of the tube member, but the throttle valve is closed. characterized in that the liquid level in the well is set to such a degree that when the vaporizer is in operation, a sufficient amount of liquid fuel passes through so that the liquid level in the well rises beyond the one end of the pipe member. This is achieved by a fuel supply structure during acceleration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

The attached figure is a longitudinal cross-sectional view showing the essential parts of one embodiment of a carburetor equipped with a fuel supply structure during acceleration according to the present invention. In the figure, 1 indicates a body of a carburetor, and the body 1 has an intake passage 2. A large bench lily 3 is provided in the middle of the intake passage 2, and a throttle valve 4 is provided downstream from the large bench lily 3. A small bench lily 5 is provided at the throat of the large bench lily 3, and the small bench lily 5 is provided with a main fuel nozzle 6 that opens into the throat.

The body 1 also has a float chamber 7 for storing liquid fuel such as gasoline.

The float chamber 7 is provided with a float 8, and a predetermined level of liquid fuel is maintained in the float chamber 7 at all times by a float valve mechanism (not shown in the figures) which is actuated by the float and which is well known in itself. It is becoming more and more common. Further, the float chamber 7 is connected to the intake passage 2 on the upstream side of the small bench lily 5 via an air vent 9. The float chamber 7 communicates with the main fuel nozzle 6 via a main jet 10, a main fuel passage 11, and a well 12. The well 12 extends vertically in the figure, and the main fuel passage 1 is connected to the main fuel passage 1 at its lower end.
1 and the main fuel nozzle 6 at its upper end, so that it can store a predetermined amount of liquid fuel. . The well 12 is provided with an emulsion tube 13 having a number of holes 14. The emulsion tube 13 is connected to an air bleed jet 15 at its upper end.

Further, a part of the body 1 is provided with an auxiliary fuel nozzle 16 that opens into the throat of the small bench lily 5, which is provided inside the main fuel nozzle 6 and concentrically therewith. Further, another well 17 is provided in the body 1.
The well 17 extends vertically in the figure, and communicates with the float chamber 7 through an auxiliary jet 18 at its lower end. The auxiliary jet 18 has a larger aperture than the main jet 10. Further, a fuel tube 19 is provided in the well 17 and opens toward the inside of the well 17 at the lower end,
This tube 19 has an auxiliary fuel passage 2 at its upper end.
It is connected to the auxiliary fuel nozzle 16 via the auxiliary fuel nozzle 16 and also to the air bleed jet 21.

Although not shown in the drawings, the carburetor described above is equipped with a slow and idle fuel supply system, an acceleration fuel pump device, etc. which are well known in the art.

When the throttle valve 4 is in the fully closed position as shown, the amount of intake air flowing through the small bench lily 5 is small, and there is substantially no negative pressure in the intake pipe of the engine upstream of the throttle valve 4. Since it does not appear in the main fuel nozzle 6
Also, fuel is not substantially supplied from the auxiliary fuel nozzle 16, and at this time, fuel is also supplied from the idle fuel supply system. Therefore, at this time, fuel is stored in the wells 12 and 17 as shown. When the throttle valve 4 is opened to perform acceleration from the above-mentioned state, fuel is supplied from an accelerating fuel pump device (not shown), and the main fuel nozzle is supplied as the intake air amount increases. Fuel will be supplied from 6 onwards. The air-fuel ratio during and immediately after acceleration is maintained at a predetermined value by the fuel from the main fuel nozzle 6 and the fuel from the acceleration fuel pump device as described above. Then, when the discharge of fuel from the acceleration fuel pump device ends with the end of acceleration, or slightly before that, the fuel stored in the well 17 passes through the tube 19 and the auxiliary fuel passage 20 according to the amount of intake air and becomes the auxiliary fuel. The fuel is sucked out from the nozzle 16 into the small bench lily 5 and compensates for the air-fuel ratio after the acceleration fuel pump device is activated. The fuel from the auxiliary fuel nozzle 16 is
The liquid level of the fuel in the well 17 is the same as that of the tube 1.
While descending to a position corresponding to the lower end of the fuel cell 9, it flows out at a relatively large flow rate and properly compensates for the air-fuel ratio. Thereafter, the fuel is auxiliary jet 1
If the main jet 10 and the main fuel nozzle 16 have their fuel passage cross-sectional areas reduced by an amount corresponding to the passage cross-sectional area of the auxiliary jet 18, steady operation is possible. Sometimes the main fuel nozzle 6
A mixture with a predetermined air-fuel ratio is created by the total fuel from the and auxiliary fuel nozzle 16,
Fuel from the auxiliary fuel nozzle 16 does not disturb the air-fuel ratio at steady state. The timing to start discharging fuel from the auxiliary fuel nozzle 16 during acceleration can be set appropriately depending on the size of the air bleed jet 21, etc., and the timing may be equal to the timing for discharging fuel from the main fuel nozzle 6, or can be slower than that.

From the foregoing description, it will be understood that the present invention provides a carburetor having an auxiliary fuel supply system that compensates for the air-fuel ratio during acceleration, particularly after activation of the acceleration fuel pump.

[Brief explanation of the drawing]

The attached figure is a longitudinal sectional view showing the essential parts of one embodiment of a carburetor equipped with a fuel supply structure during acceleration according to the present invention. 1-Body, 2-Intake passage, 3-Large bench lily, 4-Throttle valve, 5-Small bench lily, 6-Main fuel nozzle, 7-Float chamber, 8-Float, 9-Air vent, 10-Main jet, 11-main fuel passage, 12-well, 13-emulsion tube, 14-hole, 1
5-air bleed jet, 16-auxiliary fuel nozzle, 17-well, 18-auxiliary jet, 19-
Tube, 20 - auxiliary fuel passage, 21 - air bleed jet.

Claims (1)

[Scope of utility model registration request] An intake passage 2 having a bench lily portion 5, a throttle valve 4 that controls opening and closing of the intake passage downstream of the bench lily portion, and a float chamber 7 that stores liquid fuel whose liquid level is controlled to a predetermined liquid level.
and a main fuel supply system 10 to 15 that supplies liquid fuel from the float chamber to the main fuel nozzle 6 opening into the bench lily part, and the main fuel supply system is Separately, it communicates with the float chamber at a position lower than the predetermined liquid level in the float chamber through an auxiliary jet 18 having a relatively high predetermined degree of restriction, and direct liquid fuel from the float chamber via the auxiliary jet. a well 17 which is supplied with liquid fuel and can store liquid fuel up to the same liquid level as the liquid level in the float chamber; auxiliary fuel passages 19, 20, 16 that communicate from the one end of the tube member to an auxiliary fuel nozzle 16 that opens into the bench lily portion, The predetermined degree of restriction of the jet is such that the liquid level in the well 17 rises beyond the one end of the tube member 19 when the throttle valve is open and the carburetor is operating. an amount of liquid fuel that is not sufficient, but sufficient to cause the liquid level in the well 17 to rise above the one end of the tube member 19 when the carburetor is operating with the throttle valve closed; A fuel supply structure during acceleration, characterized in that the fuel supply structure is set to a degree that allows the passage of the fuel.