JPH0144776Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fuel concentration control device, and more particularly to a fuel concentration control device using a piston valve type carburetor.

It is known that starting and idling a cold engine requires rich fuel. However, if the concentration of the air-fuel mixture is adjusted to suit when the engine is cold, there is a risk of excessive fuel consumption after warming up.

In view of these problems, the present invention provides a fuel concentration control device that improves fuel efficiency during high-speed driving. At this time, the flow control valve installed in the piston valve is opened to increase the amount of air supplied to the intake pipe.
The first step is to further dilute the air-fuel mixture supplied to the engine.

The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a diagram showing an installation mode of a fuel concentration control device according to the present invention. As shown in FIG. 2, this fuel concentration control device 1 has an inlet port 4 and an outlet port 5 formed on the side wall of a housing 3 of a piston valve type carburetor main body 2. The inlet port 4 is connected to the inlet 7a of the bore 7 of the carburetor body 1 through a pipe 6, and the outlet port 5 is connected to the crankcase cover through a pipe 8 as shown in FIG. It communicates with an inlet port 10a of a thermovalve 10 installed at 9. On the other hand, a hole 12 is formed in the side wall of the piston valve 11, and the hole and the outlet port 5 constitute a flow rate control valve 13. Furthermore, in this fuel concentration control device 1, the outlet port 10b of the thermovalve 10 is communicated with the intake pipe 16 of the engine 15 through the pipe 14. In FIGS. 1 and 2, reference numeral 7b indicates an outlet portion of the bore 7, 17 indicates a return spring for pressing down the piston valve 11, and 18 indicates a return spring.
is the throttle wire, 19 is the spring housing chamber,
20 is a float chamber, 21 is a needle jet, 2
2 is the jet needle, 23 is the main jet,
24 is an air cleaner, and 25 is a pipe connecting the air cleaner and the bore 7 of the carburetor 2.

The operation of the above-described embodiment will be explained below, and the structure thereof will also be explained in more detail. Flow control valve 13
As a result of the upward movement of the piston valve 11, the hole 12 of the valve overlaps the outlet port 5, thereby enlarging its opening area. Accordingly, the secondary air flows into the pipe 8 from the spring housing chamber 19. The thermovalve 10 detects the atmospheric temperature inside the crankcase cover, and when the temperature reaches a specified temperature or higher, connects the inlet port 10a and the outlet port 10b.

When the engine is cold, the thermovalve 10 is closed, and even if the piston valve 11 is moved upward by the throttle wire 18 and the flow control valve 13 is opened, secondary air does not flow into the intake pipe 16. Therefore, all the air taken in from the air cleaner 24 is supplied to the intake pipe 16 from the fuel supply system, ie, the air cleaner, through the pipe 25 and the bore 7. At this time, the fuel supplied from the needle jet 21 is mixed with air in the bore 7 to an appropriate concentration, and the mixture is supplied to the engine 15 through the intake pipe 16. During warm-up operation, the thermovalve 10 is open, and when the piston valve 11 reaches a certain opening degree or more, the outlet port 5
opens from the closed state shown in FIG. 3a to the open state shown in FIG. 3b. Therefore, from the return spring housing chamber 19, the secondary air passes through the air cleaner 24, the pipe 6, and the inlet port 4, flows into the pipe 9 via the outlet port 5, and further flows into the intake pipe 16 through the thermovalve 10 and the pipe 14. The air-fuel mixture in the bore 7 is further diluted. In this way, the upward movement of the piston valve 11 opens the flow control valve 13, and finally the third
As shown in Figure c, the opening degree reaches its maximum, and the amount of air supplied into the intake pipe increases.
The air-fuel mixture supplied to the engine from the needle jet 21 is stabilized in a diluted state.

In the above embodiment, the flow control valve 13 is installed on the outlet side, but it goes without saying that it may be installed on the inlet side, and the secondary air supply port is inside the intake pipe 16. , there is no problem even if it is the outlet portion 7b of the bore 7 of the carburetor main body 2. Furthermore, thermo valve 10
Of course, it may be installed at a location other than the crankcase cover as long as the temperature of the engine can be detected.

As mentioned above, the fuel concentration control device according to the present invention introduces secondary air into the intake pipe according to the throttle opening during normal warm-up operation, so that the air-fuel mixture is maintained without impairing engine performance. It is diluted and is extremely advantageous in terms of fuel efficiency.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing the installation mode of the fuel concentration control device according to the present invention, Fig. 2 is a sectional view of the main part thereof, and Figs. 3 a, b, and c are diagrams showing the operating state of the flow rate control valve. It is. DESCRIPTION OF SYMBOLS 1...Fuel concentration control device, 2...Carburizer main body, 3...Housing, 4...Inlet port, 5...Outlet port, 6...Pipe, 8...Pipe, 10...Thermovalve, 11
... Piston valve, 12 ... Hole, 13 ... Flow rate control valve, 14 ... Pipe, 19 ... Spring housing chamber, 21 ... Needle jet, 24 ... Air cleaner, 25 ... Pipe.

Claims (1)

[Scope of utility model registration request] A hole is formed in the side wall of the piston valve of the piston valve type carburetor, and an inlet port and an outlet port are formed in the housing of the piston valve carburetor, and the flow rate is controlled by at least one of these ports and the hole. A control valve is configured, and the inlet port communicates with the upstream side of the piston valve of the fuel supply system, and the outlet port communicates with the downstream side of the piston valve of the fuel supply system, so that the throttle opening is set to a predetermined degree. A fuel concentration control device, characterized in that the fuel concentration control valve is opened when the opening degree of the fuel concentration reaches or exceeds the opening degree of the fuel concentration control valve.