JPH0628244U - Mixer concentration controller for vaporizer - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Regarding the engine carburetor, at the time of high opening of the throttle valve, the mixture concentration is increased by adding means other than the low speed fuel system S and the main fuel system M. To do. A correction air passage 11 communicating with the intake passage 3A on the upstream side of the venturi portion 2 or the atmosphere is opened near the most sandwiched portion 2A of the venturi portion 2, and the correction air passage 11 is opened when the throttle valve 7 is at a high opening degree. More corrective air is ejected to the venturi section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vaporizer that controls the amount and concentration of air-fuel mixture supplied to an engine.

[0002]

[Prior art]

 For the carburetor installed in the engine, the main fuel system, the fuel jet and the air jet that constitute the low-speed fuel system are selected in order to obtain a mixture suitable for the engine. On the other hand, according to the setting work of the carburetor only by selecting the hole diameter of each jet, the allowable range for setting is relatively narrow, and it takes a lot of time for the setting work. There is one that arranges an air adjusting screw for adjusting and controlling the amount of air flowing through the air passage communicating with the low-speed fuel system and adjusts the air adjusting screw to make the air amount variable, thereby controlling the concentration of the air-fuel mixture. (For example, Japanese Utility Model Publication No. 41-3529)

[0003]

[Problems to be solved by the device]

 According to such a conventional carburetor, adjustment and control of the concentration of the air-fuel mixture can be achieved by screwing the air adjusting screw to adjust the amount of air flowing in the main fuel system or the low speed fuel system. It is difficult to adjust the concentration. That is, the downstream side of the air passage is not opened to the intake passage to which the intake negative pressure is directly applied, but is opened to the fuel passage of the main fuel system or the low-speed fuel system. Since a large intake negative pressure generated inside cannot be directly applied, the air amount cannot be controlled sufficiently and satisfactorily. That is, the amount of air flowing through the air passage is determined by how much intake negative pressure is applied to the air passage.

The present invention has been made in view of the above problems, and particularly provides a mixture concentration control device for a carburetor capable of thickening the mixture concentration at a high opening of a throttle valve. And in.

[0005]

[Means for solving the problem]

 According to the present invention, the venturi portion is provided in the intake passage that penetrates the carburetor body, and the throttle valve attached to the throttle valve shaft is arranged on the engine side of the venturi portion to control the opening area of the intake passage. In a carburetor that opens the low-speed fuel system facing the throttle valve and opens the main fuel system in the venturi part, a correction air that is connected to the intake passage upstream of the venturi part or the atmosphere near the most sandwiched part of the venturi part. It is an open passage.

[0006]

[Action]

 With the throttle valve open to a high opening, the correction air is sucked into the venturi section from the correction air passage. According to this, the air flow in the venturi section is disturbed, the amount of air flowing down the venturi section is reduced, and the mixture concentration is increased.

[0007]

【Example】

 An embodiment of the air-fuel mixture concentration control device of the vaporizer according to the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a carburetor body through which an air intake passage 3 having a venturi portion 2 penetrates, and the air intake passage 3 has a substantially sandwiched portion 2A (a portion where the effective area of the venturi portion 2 is the smallest) substantially in the middle thereof. Has a venturi section 2 having air, and air flows in from an intake path 3A on the upstream side of the venturi section 2. This air passes through the venturi section 2 and flows down to an intake path 3B downstream from the venturi section 2. Reach an institution (not shown). A float chamber main body 4 is disposed below the vaporizer main body 1, and a float chamber 5 is formed by the vaporizer main body 1 and the float chamber main body 4, and a constant fuel liquid level XX is formed in the float chamber 5. Formed and retained. Reference numeral 6 denotes a throttle valve shaft rotatably supported by the carburetor main body 1 in the intake passage 3B downstream of the venturi portion 2. The throttle valve shaft 6 has a plate-shaped throttle valve 7 (hereinafter simply referred to as a throttle valve). ) Is attached, and the throttle valve 7 controls the intake passage 3 to open and close. M is a main fuel system, which is connected to the inside of the liquid surface of the float chamber 5 through a main fuel jet 8 and is connected to a main air jet (not shown) connected to the atmosphere, and is restricted by the main fuel jet 8. The generated main fuel and the main air restricted by the main air jet are mixed in the main nozzle 9, and the main air-fuel mixture is sucked toward the Venturi section 2 from the tip opening of the main nozzle 9. S is a low-speed fuel system, which is connected to the fuel level of the float chamber 5 through a low-speed fuel jet (not shown) and is also connected to a low-speed air jet connected to the atmosphere (not shown). The low speed fuel restricted by the low speed air and the low speed air restricted by the low speed air jet are mixed, and the low speed air-fuel mixture is sucked out from the opening of the bypass hole 10 toward the intake passage 3B.

The above is a conventionally known vaporizer, and in the present invention, the following configuration is added to achieve the above object. Reference numeral 11 denotes a correction air passage, the downstream side 11A opens near the most sandwiched portion 2A of the venturi portion 2, and the upstream side 11B is from the venturi portion 2 (the distance of the venturi portion 2 is indicated by A in the figure). It is connected to the intake passage 3A on the upstream side or the atmosphere.

Next, the operation will be described. First, the low opening operation of the throttle valve 7 (the state of the throttle valve shown in FIG. 1) will be described. During such a low opening operation of the throttle valve 7, a large negative pressure acts on the intake passage on the downstream side of the throttle valve 7. According to this, in the intake passage on the downstream side of the throttle valve 7, The low-speed air-fuel mixture is sucked into the intake passage 3 through the bypass hole 10 serving as the low-speed fuel system S that is opened. On the other hand, the venturi portion 2 sucks the correction air into the venturi portion 2 from the correction air passage 11 though a small flow rate of air corresponding to the low opening degree of the throttle valve 7 flows. Therefore, the low speed mixture is controlled by the low speed fuel system. (Generally, the air-fuel mixture is not sucked from the main fuel system M.) Then, when the throttle valve 7 enters the middle opening operation as shown by the dotted line in the figure, in addition to the supply of the air-fuel mixture from the low-speed fuel system S, The air-fuel mixture is supplied from the main fuel system M. On the other hand, in the Venturi section 2, the medium flow rate of air corresponding to the middle opening degree of the throttle valve 7 flows and the correction air is sucked into the Venturi section 2 from the correction air passage 11, but the amount of air supplied to the engine is increased. Is restricted by the middle opening degree of the throttle valve 7 and does not disturb the air flow flowing through the most narrowed portion 2A of the Venturi portion 2, so that the medium speed mixture of the low speed fuel system S and the main fuel system M 1 is supplied. During the middle opening operation of the throttle valve 7, the air flow flowing through the most sandwiched portion 2A of the venturi portion 2 is not disturbed by the correction air because the flow velocity (negative pressure) of the venturi portion 2 is increased. This is because the air flow, which is relatively medium, is not disturbed by the air flow sucked from the correction air passage 11 to the air flow flowing through the venturi portion 2. Next, the high-opening operation of the throttle valve 7 in which the throttle valve 7 is opened to near the fully open state will be described. When a high opening operation of the throttle valve 7 shown by the alternate long and short dash line in the figure is entered, the flow velocity (negative pressure) of the most narrow portion 2A of the Venturi portion 2 rises greatly, and the air-fuel mixture mainly flows from the main fuel system M to the intake passage 3 It is sucked inside. On the other hand, the correction air is ejected (sucked) at a high speed from the downstream side 11A of the correction air passage 11 opening to the most sandwiched portion 2A of the venturi portion 2 to the most sandwiched portion 2A of the venturi portion 2. According to this, the horizontal airflow flowing down the venturi section 2 toward the engine is largely disturbed by the correction airflow, and the amount of air flowing down to the engine side is reduced. Based on the above, the air-fuel mixture concentration becomes thicker in proportion to the decrease in the air amount. It is clear from the diagram in FIG. 2 that the concentration of the air-fuel mixture is increased by increasing the opening of the throttle valve in this way. In FIG. 2, the specification P indicates a conventional carburetor without the correction air passage 11, and the specification R is based on the present invention in which the correction air passage 11 having a diameter of 3 mm is opened in the most sandwiched portion 2A of the venturi portion 2. It is understood from FIG. 2 that the air-fuel mixture concentration is high at high opening of the throttle valve 7. Thus, by selecting the hole diameter of the correction air passage 11, it becomes possible to increase the concentration of the air-fuel mixture in the throttle valve 7, especially during high-open operation.

[0010]

[Effect of device]

 As described above, according to the mixture concentration control device of the carburetor according to the present invention, the venturi portion is provided in the intake passage passing through the carburetor main body, and the throttle valve attached to the throttle valve shaft on the engine side of the venturi portion is attached to the throttle valve shaft. In order to control the opening area of the intake passage and to open the low-speed fuel system facing the throttle valve and to open the main fuel system in the venturi part, in the carburetor near the most sandwiched part of the venturi part, Since the correction air passage leading to the intake passage or the atmosphere on the upstream side of the section is opened, it is possible to set the mixture concentration at a high opening of the throttle valve to be richer than the conventional control by the main fuel system. The carburetor can be set more easily.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a mixture concentration control device for a vaporizer according to the present invention.

FIG. 2 is a diagram showing the relationship between air-fuel mixture concentration and intake air amount.

[Explanation of symbols]

 1 Vaporizer main body 2 Venturi section 2A Venturi section most sandwiched section 3 Intake passage 3A Intake passage upstream of Venturi section 11 Corrected air passage

Claims (1)

[Scope of utility model registration request] 1. A venturi portion 2 is provided in an intake passage 3 penetrating the carburetor body 1, and a throttle valve 7 attached to a throttle valve shaft 6 is arranged on the engine side of the venturi portion 2 to open the intake passage 3. In the carburetor in which the area is controlled and the low speed fuel system S is opened to face the throttle valve 7 and the main fuel system M is opened in the venturi portion 2, the venturi portion 2 is provided in the vicinity of the most sandwiched portion 2A of the venturi portion 2. An air-fuel mixture concentration control device for a carburetor in which a correction air passage 11 communicating with the intake passage 3A on the upstream side or the atmosphere is opened.