JPH018682Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for preventing engine stoppage by icing the slow fuel passage of a piston valve type carburetor used in a motorcycle engine or the like.

The temperature near the throttle valve of the carburetor is that the fuel is sucked out under negative pressure and vaporized, so the heat of vaporization is taken away and the temperature drops significantly.When the outside air is low, the exit of the slow fuel passage is This is inconvenient because the icing phenomenon occurs when the water contained in the pipe freezes and the fuel stops flowing, causing the engine to stop. Large engines use temperature-controlled cleaners that send warm air to the cleaner to prevent icing, but smaller engines with piston-valve carburetors do not use such cleaners, so icing can occur. Sometimes.

In view of this point, this invention is an improvement to prevent engine stoppage due to icing using a piston valve type carburetor.Hereinafter, an embodiment of the invention shown in the drawings will be described.

The carburetor 1 connects the outlet of a transversely penetrating main air passage 2 to the end of an intake pipe 3 of the engine. A cylindrical throttle valve 5 is slidably inserted into a guide cylinder 4 that intersects with the main air passage 2, and the main air passage 2 is opened and closed by sliding the throttle valve 5 up and down. control. A main fuel passage 6 opens directly below the throttle valve 5 in the main air passage 2, into which a needle valve 7 protruding from the lower end of the throttle valve 5 is inserted.
The opening area is adjusted by raising and lowering the opening area. A slow fuel passage 8 is open on the rear side of the main fuel passage 6, and when the throttle valve 5 is at a low opening degree, fuel is sucked out and supplied from the slow fuel passage 8. . By the way, the slow fuel passage 8 and the suction pipe 2 are diagonally connected, and a diagonal hole 9 is bored to form a second slow fuel passage. A negative pressure on/off valve 10 is provided in the diagonal hole 9 in the middle. The negative pressure on/off valve 10 has a valve stem 1
The horizontal hole 12 of No. 1 is pushed by the spring 13 and coincides with the diagonal hole 9 so that the diagonal hole 9 communicates with the negative pressure chamber 1.
When the valve stem 11 is pulled by the diaphragm 15 due to the negative pressure acting against the spring 13 at 4, the horizontal hole 12 is disengaged from the oblique hole 9 and closed. The negative pressure chamber 14 is connected to the suction pipe 3 through a pipe 16.

However, when fuel is being sent smoothly from the slow fuel passage 8, the engine also rotates correctly.
The negative pressure in the suction pipe 3 is high, and the negative pressure is working in the negative pressure chamber 14, pulling the valve stem 11 and closing the diagonal hole 9. Icing starts when the engine is idling, and moisture in the intake air freezes near the outlet of the slow fuel passage 8, making it difficult for fuel to flow from the slow fuel passage 8. This causes the engine rotation to drop and the negative Pressure decreases. Therefore, the valve rod 11 is pushed forward by the spring 13, the horizontal hole 12 opens to meet the diagonal hole 9, and slow fuel is supplied to the suction pipe 3 through the diagonal hole 9. In this way, even if the slow fuel passage 8 is blocked, the diagonal hole 9 is opened and slow fuel continues to be supplied to the intake pipe 3, thereby preventing the engine from stopping due to aging. Incidentally, when the throttle valve 5 is opened, fuel is supplied from the main fuel passage 6, and both the slow fuel passage 8 and the oblique hole 9 have no relation to fuel supply.

As explained above, this invention provides a slow fuel passage of a carburetor with a diagonal hole communicating from the slow fuel passage to the suction pipe, a negative pressure on-off valve is provided in the middle of the diagonal hole, and the negative pressure on-off valve The negative pressure chamber of the engine is connected to the suction pipe with a pipe, and the pressure in the negative pressure chamber that operates the valve stem of the negative pressure on/off valve is controlled by the negative pressure of the engine as the engine speed decreases below the engine's idling speed. Therefore, when fuel is being supplied normally from the slow fuel passage, the engine rotates correctly and the negative pressure is large and the diagonal hole is closed, but if the flow of fuel from the slow fuel passage becomes poor due to icing, As the engine speed decreases and the negative pressure in the intake pipe decreases, the negative pressure on/off valve opens, and slow fuel is supplied from the diagonal hole, preventing the engine from stopping and preventing the engine from stopping due to icing. . Also, it is cheaper than using a temperature-controlled air cleaner.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal sectional side view and FIG. 2 being an enlarged longitudinal sectional side view of the main parts. DESCRIPTION OF SYMBOLS 1... Carburetor, 2... Main air passage, 3... Intake pipe, 8... Slow fuel passage, 9... Diagonal hole, 10...
...Negative pressure on/off valve, 16...pipe.

Claims (1)

[Scope of utility model registration request] A diagonal hole leading from the slow fuel passage to the suction pipe is provided in the slow fuel passage of the carburetor, a negative pressure on-off valve is provided in the middle of the diagonal hole, and the negative pressure chamber of the negative pressure on-off valve is connected to the suction pipe with a pipe. A carburetor, characterized in that the negative pressure indoor pressure that operates the valve stem of the negative pressure on/off valve is controlled by the negative pressure of the engine as the engine speed decreases below the set idling speed of the engine. Device to prevent engine stoppage due to slow fuel passage icing.