JPH057483Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an auxiliary fuel supply device that adjusts auxiliary fuel by an emulsion rotation speed control valve provided downstream of a throttle valve of a carburetor. The present invention relates to an auxiliary fuel supply device for a carburetor that matches the total fuel supply amount to the engine required fuel amount during engine no-load operation.

[Description of Prior Art] Conventional Rara carburetors are equipped with an engine speed control valve (hereinafter referred to as governor valve) that changes the cross section of the intake passage depending on the engine speed on the downstream side of the carburetor throttle valve. The one equipped with an auxiliary fuel supply device that adjusts auxiliary fuel using a governor valve was developed in the 1970s.
It is shown in No. 26765 etc. This conventional example is shown in FIG. 4 as a sectional view of a main part. An intake passage 12 is formed within the carburetor body 10, and the carburetor body 10 is slidably provided with a piston valve 14 that changes the cross section of the intake passage 12. A throttle valve 16 that rotates in conjunction with the sliding movement of the piston valve 14 is provided in the intake passage 12 on the downstream side of the position of the piston valve 14 (a connection mechanism between the piston valve 14 and the throttle valve 16). (omitted). A governor valve 18 is provided downstream of the throttle valve 16. This governor valve 18 changes the opening degree according to the engine speed to vary the cross section of the intake passage.During no-load operation, the cross-section of the intake passage narrows to a constant opening degree, and when operating under load, the cross-section of the intake passage narrows. It is intended to widen the range of A jet needle 20 is attached to the tip of the piston valve 14, and the amount of main fuel from within the float chamber 22 is adjusted by the jet needle 20.

Inside the carburetor body 10, there is a fuel passage 24 communicating from the float chamber 22, an atmospheric passage 26 introducing the atmosphere, and a governor valve 18 of the intake passage 12 where the fuel passage 24 and the atmospheric passage 26 merge.
A governor bypass emulsion passage 28 that opens nearby is formed. The opening position of the emulsion passage 28 is such that negative pressure is applied to the opening of the emulsion passage 28 by the governor valve 18 when the engine is opened during no-load operation. A throttle 30 and a throttle 32 are provided in the middle of the fuel passage 24 and the middle of the atmosphere passage 26, respectively. A solenoid valve 34 is provided in the middle of this emulsion passage 28, and when the opening degree of the throttle valve 16 is larger than the idling opening degree, the solenoid valve 34 is turned ON and the emulsion passage 28 is opened.

FIG. 5 shows the fuel flow rate during no-load operation of the engine in a carburetor having such a conventional configuration. Since the opening degree of the governor valve 18 is constant during no-load operation of the engine, the auxiliary fuel flow rate is as shown by the solid line A,
A fixed amount of fuel is supplied from the On the other hand, the main fuel flow rate is as shown by the dashed line B.
The flow rate decreases as the throttle valve opening increases. The total fuel flow rate of the auxiliary fuel and the main fuel decreases as the throttle valve opening increases, as shown by the solid line C. That is, the flow rate is minimum when the throttle valve is at its maximum opening, and this minimum flow rate is adjusted to match the fuel flow rate required by the engine.

[Problems to be solved by the invention] However, the amount of fuel required by the engine during no-load operation is constant regardless of the throttle valve opening, so with a conventional carburetor configuration, the throttle valve opening is Except at peak times, extra fuel was provided. As a result, the economy is poor;
There was a problem that the amount of waste gas increased.

[Purpose of the invention] The present invention was made in view of the above points, and it adjusts the amount of auxiliary fuel during no-load operation of the engine to meet the engine's fuel demand regardless of the throttle valve opening. It is an object of the present invention to provide an auxiliary fuel supply device for a carburetor that supplies a constant amount of fuel to an engine in accordance with the flow rate.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a piston valve and a throttle valve that operate in conjunction with each other to vary the cross section of the intake passage of the carburetor body;
There is a governor valve that changes the cross section of the intake passage depending on the engine speed, an emulsion passage that opens into the intake passage near the governor valve, and an emulsion passage that opens into the intake passage near the governor valve. In an auxiliary fuel supply device for a carburetor having a solenoid valve for opening an emulsion passage, means is provided for varying the cross section of the emulsion passage in conjunction with the operation of the piston valve, and the means is configured to increase the opening degree of the piston valve. Accordingly, the cross section of the emulsion passage is made wider.

[Operation] The cross section of the emulsion passage is varied according to the sliding movement of the piston valve or the opening degree of the throttle valve. The cross section of this emulsion passage is narrowed when the piston valve or throttle valve narrows the cross section of the intake passage, and widened when the cross section of the intake passage is widened. That is, as the opening degree of the throttle valve increases, the amount of main fuel decreases and the amount of auxiliary fuel increases. As a result, the sum of the main fuel and the auxiliary fuel is always constant in accordance with the amount of fuel required by the engine, regardless of the opening degree of the throttle valve.

[Example] Next, the present invention will be explained based on the drawings.

FIG. 1 is a cross-sectional view of the structure of the auxiliary fuel supply device for a carburetor according to the present invention, FIGS. 2 and 3 are enlarged cross-sectional views of the intersection of the piston valve rotation axis and the emulsion passage, and FIG. FIG. 3 is a sectional view when the valve opening is small, and FIG. 3 is a sectional view when the piston valve opening is large. In these figures, the same reference numerals as in FIG. 4 indicate the same parts.

The difference between the embodiment of the present invention and the conventional example is that the emulsion passage 36 is connected to the piston valve 16.
The rotating shaft 38 of
Hole 4 which becomes the passage part of emulsion passage 36 is shown in 8.
0 is formed. The hole 40 formed in the rotating shaft 38 reduces the cross section of the emulsion passage 36 when the opening degree of the piston valve 16 is small, and reduces the cross section of the emulsion passage 36 proportionally when the opening degree of the piston valve 16 increases. Set it to be larger. This emulsion passage 3
6 is opened and closed by the solenoid valve 34.

With the above structure, when the engine is operating under no load and the opening degree of the throttle valve 16 is larger than the idling opening degree, the solenoid valve 34 is turned ON and the emulsion passage 36 is opened. As the opening degree of the throttle valve 16 (or piston valve 14) increases, the rotating shaft 38 of the piston valve 14 rotates from the state shown in FIG. 2 to the state shown in FIG. 3. That is,
According to the change in the position of the hole 40 of the rotating shaft 38, the passage cross section of the emulsion passage 36 becomes larger, and the amount of auxiliary fuel passing through it also increases.
increases as the degree of opening increases.

Here, the amount of auxiliary fuel flowing from the emulsion passage 36 during no-load operation of the engine increases as the throttle valve opening degree increases, as shown by the dotted line D in FIG. On the other hand, the main fuel flow rate decreases as the throttle valve opening increases, as shown by the dashed line (b). The total flow rate of these auxiliary fuels and the main fuel remains the same even if the throttle valve opening changes, as shown by the dotted line H. That is, it can match the fuel flow rate required by the engine.

Note that the emulsion passage 3 in the above embodiment
As a means for varying the cross section of the piston valve 6, a rotary shaft 38 of the piston valve is installed in the middle of the emulsion passage 36.
Although an example is shown in which the cross section of the hole 40 and the emulsion passage 36 is varied on the rotary shaft 38, the cross section of the emulsion passage 36 is varied depending on the movement of the interlocking mechanism of the piston valve 14 and the throttle valve 16. Any means that can vary the cross section of the emulsion passage 36 may be used.

Furthermore, in the embodiment, the float chamber 22
The fuel passage 24 communicating with the atmosphere, the atmosphere passage 26 introducing the atmosphere, and the emulsion passage 36 where the fuel passage 24 and the atmosphere passage 26 join together have been formed. A branch passage opening from the starter fuel passage to the governor valve position may be formed, and a solenoid valve may be disposed in the branch passage.

[Effects of the invention] As described above, according to the auxiliary fuel supply device for a carburetor according to the invention, the cross section of the emulsion passage is adjusted according to the opening degrees of the piston valve and the throttle valve during no-load operation of the engine. By making it variable, the auxiliary fuel flow rate can be variably increased as the opening degree of the throttle valve becomes larger. As a result, the total fuel of the main fuel and the auxiliary fuel can be kept at a constant flow rate, which is the fuel amount required by the engine, regardless of the opening degree of the throttle valve.

In addition, a hole is formed in the rotating shaft of the piston valve, and the hole in the rotating shaft is used as a part of the emulsion passage, so that the emulsion passage can be changed by rotating the rotating shaft, so a new part is added. It is not necessary and is advantageous in terms of cost.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the structure of the auxiliary fuel supply device for a carburetor according to the present invention, Figs. 2 and 3 are enlarged sectional views of the intersection of the piston valve rotation axis and the emulsion passage, and Fig. 4 is a conventional auxiliary fuel supply device. FIG. 5, which is a sectional view of the configuration of the auxiliary fuel supply device for the carburetor, is a characteristic diagram showing the relationship between the throttle valve opening and the fuel flow rate. 10... Carburetor body, 12... Intake passage, 14
... Piston valve, 16 ... Throttle valve, 18 ... Governor valve, 34 ... Solenoid valve, 36 ... Emulsion passage, 38 ...
Rotating axis, 40... hole.

Claims (1)

[Claims for Utility Model Registration] (1) A piston valve 14 and a throttle valve 16 that operate in conjunction with each other in order to vary the cross section of the intake passage 12 of the carburetor body 10, and the intake passage according to the engine speed. a governor valve 18 whose cross section is variable; an emulsion passage 36 that opens into the intake passage 12 near the governor valve 18; In an auxiliary fuel supply device for a carburetor having a solenoid valve 34 for opening the emulsion passage 36, means is provided for varying the cross section of the emulsion passage 36 in conjunction with the operation of the piston valve 14, and the means An auxiliary fuel supply device for a carburetor, characterized in that the cross section of the emulsion passage 36 becomes wider as the opening degree of the piston valve 14 becomes larger. (2) The means for varying the cross section of the emulsion passage 36 includes a rotating shaft 38 that rotates as the piston valve 14 moves, and a hole 40 provided in the rotating shaft 38 that becomes a part of the emulsion passage 36. An auxiliary fuel supply device for a carburetor according to claim 1, characterized in that the device comprises: