JPH0738678Y2 - Secondary throttle valve controller for carburetor - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention synthesizes the negative pressures of the primary and secondary large venturi parts and controls the opening / closing of the secondary throttle valve by the opening force of the diaphragm corresponding to the combined negative pressure. Control device.

(Prior Art) Conventionally, in the case of a control device that combines the negative pressures of the primary and secondary large venturi parts and controls the secondary throttle valve by opening and closing the diaphragm according to the combined negative pressure, high engine rotation There was a method to cut off the ignition to prevent overrun.

(Problems to be Solved by the Invention) The above-mentioned conventional engine high rotation overrun preventing means is
When applied to a vehicle equipped with a catalyst device, there is a problem that the catalyst cannot be adopted because there is a risk of catalyst dissolution loss due to misfire.

Therefore, in the present invention, when the secondary venturi negative pressure of the carburetor becomes a predetermined value or more, the secondary throttle valve is closed to reduce the output of the engine so that it can be applied to a vehicle with a catalyst device. Preventing run is a technical issue to be solved.

(Means for Solving the Problem) The technical means for solving the above problem is to open and close the secondary throttle valve by balancing the opening force of the diaphragm and the closing force of the compression spring to control the air flow rate through the secondary bore. The secondary throttle valve control device of the carburetor, the solenoid valve for communicating the negative pressure passage for operating the diaphragm with the atmosphere, and the secondary venturi negative pressure are detected, and the detected negative pressure becomes a predetermined value or more. And a negative pressure switch for releasing the negative pressure in the diaphragm negative pressure passage to the atmosphere.

(Operation) According to the secondary throttle valve control device of the carburetor having the above configuration, the negative pressure switch detects the secondary Venturi negative pressure, and outputs a signal to the solenoid valve to operate when the detected negative pressure becomes a predetermined value or more. By releasing the negative pressure in the diaphragm negative pressure passage to the atmosphere, the opening force of the diaphragm is reduced, and by closing the secondary throttle valve, high engine overrun is prevented.

(Embodiment) Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 has a primary venturi 1 and a secondary venturi 2, and a secondary throttle valve of a carburetor that operates a secondary throttle valve 3 and a diaphragm 4 for opening / closing control by a combined negative pressure of the primary venturi 1 part and the secondary venturi 2 part. It is a schematic system diagram of a control apparatus.

As shown in the figure, the composite negative pressure of the primary venturi 1 part and the secondary venturi 2 part is applied to the diaphragm 4 via the diaphragm operating negative pressure passage 5. Further, at the end of the negative pressure branch passage 7 branched from the secondary bore 6, the negative pressure of the secondary venturi 2 part is detected, and a negative pressure that outputs a signal when the detected negative pressure exceeds a set value. The switch 8 is attached. On the other hand, a branch passage 9 is connected to the diaphragm operating negative pressure passage 5, and a solenoid valve 10 for releasing the negative pressure of the diaphragm operating negative pressure passage 5 to the atmosphere is attached to an end of the branch passage 9. ing. The solenoid valve 10 is electrically connected to the negative pressure switch 8 and operates when the signal is output from the negative pressure switch 8 so that the negative pressure in the diaphragm operating negative pressure passage 5 is released to the atmosphere. Has become.

With the configuration described above, the negative pressure switch 8 detects the negative pressure of the secondary venturi 2 part via the negative pressure branch path 7, and the detected negative pressure reaches the set value A as shown in FIG. At this time, an operating current is applied to the solenoid valve 10 to open the solenoid valve 10. As a result, the diaphragm operating negative pressure passage 5 is communicated with the atmosphere via the branch passage 9 and the solenoid valve 10, so that the diaphragm operating negative pressure passage 5 becomes close to the atmospheric pressure, and the diaphragm 4 closes the secondary throttle valve 3. And decreases the output of the engine, as shown in FIG.

As described above, according to the present invention, when the secondary venturi negative pressure of the carburetor becomes a predetermined value or more, the negative pressure of the diaphragm negative pressure passage is released to the atmosphere to reduce the opening force of the diaphragm. Since the secondary throttle valve is closed by the above, there is an effect that the output of the engine can be reduced and the high rotation overrun of the engine can be prevented.

[Brief description of drawings]

The drawings relate to the embodiment, FIG. 1 is a schematic system diagram of a secondary throttle valve control device of a carburetor, and FIG. 2 is an operation characteristic diagram of a secondary throttle valve control device of a carburetor. 1 ... Primary venturi 2 ... Secondary venturi 3 ... Secondary throttle valve 4 ... Diaphragm 5 ... Diaphragm operation negative pressure passage 6 ... Secondary bore, 7 ... Negative pressure branch passage 8 ... Negative pressure switch, 9 ... … Branch 10 …… Solenoid valve

Claims (1)

[Scope of utility model registration request] 1. A secondary throttle valve control device for a carburetor, wherein a secondary throttle valve is opened and closed by balancing the opening force of a diaphragm and a closing force of a compression spring to control the flow rate of air flowing through a secondary bore. A solenoid valve for communicating the negative pressure passage for communicating with the atmosphere, and a secondary venturi negative pressure is detected, and when the detected negative pressure becomes a predetermined value or more, a signal is output to the solenoid valve to operate the diaphragm. A secondary throttle valve control device for a carburetor, comprising: a negative pressure switch for releasing the negative pressure in the negative pressure passage to the atmosphere.