JPS6060031B2 - Vaporized fuel absorption control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that controls fuel and evaporated fuel from a fuel tank or the like by controlling the intake negative pressure of the engine and draws it into the engine.

Traditionally, vehicles equipped with an engine have a fuel tank,
In order to prevent the evaporated fuel generated from the intake manifold, carburetor, etc. from leaking into the atmosphere and polluting the atmosphere, there is a device that collects the evaporated fuel in a canister device with built-in activated carbon. The evaporated fuel collected in the device is sucked into the engine by its intake negative pressure when the engine is operating.

However, since one end of this canister device is open to the atmosphere, when the engine is idling or decelerating, a large amount of air from the atmosphere is sucked into the intake manifold along with evaporated fuel due to the extremely high intake negative pressure of the engine. In this case, there was a problem that the engine operation became unstable. The present invention provides an evaporative fuel absorption control device that solves this problem.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, 1 is an engine, 2 is a carburetor, 3 is an air cleaner, 4 is a fuel tank, and 5 is a canister device.

This canister device 5 has an activated carbon layer 7 in the center of the container 6.
The inside of the container 6 is divided into chambers 8 and 9,
The chamber 8 is open to the atmosphere, and the chamber 9 is connected to the upper part of the fuel tank 4 via a passage 10. 11 is a fuel adjustment device attached to the bottom of the fuel tank 4.

As shown in FIG. 2, this fuel adjustment device 11 includes a first body 13 that is screwed into a fuel outlet 12 at the bottom of the fuel tank 4, and a first body 13 that is attached to the first body 13 with a bolt 14. 2 main bodies 15 and the first main body 13, one end communicates with the fuel tank 4, and the other end communicates with the surface 1 of the first main body 13.
A first fuel passage 16 opens to the surface 13a, and a second fuel passage 17 and a third fuel passage 18 are bored through the first body 13 and have one end opened to the surface 13a. The fuel adjustment device 11 also includes a manual cock 19 that opens and closes the fuel passages 16 and 17, a fuel control valve 20 that opens and closes the fuel passages 17 and 18, and a diaphragm 21 held between the main bodies 13 and 15. , a chamber 22 formed between the second body 15 and the diaphragm 21, boats 23 and 24 bored in the second body 15 and communicating with the chamber 22, and the boat 23.
It has an evaporative fuel control valve 25 that opens and closes the evaporative fuel control valve 25. The manual cock 19 is rotatably held on the first body 13 by a lid 26 attached to the first body 13, and one surface 19a thereof is in close contact with the surface 13a.

This surface 19a is provided with fuel passages 16 and 1 only when the lever 19b of the manual cock 19 is directed downward as shown.
A fuel guide groove 27 that communicates with the fuel guide groove 7 is formed. The fuel control valve 20 includes a tapered valve seat 28 formed between the fuel passages 17 and 18, a valve body 29 held by a diaphragm 21, and a seal attached to the valve body 29 facing the valve seat 28. It is composed of a ring 30 and a spring 31 that urges the valve body 29 toward the valve seat 28. The evaporated fuel control valve 25 includes a valve body 32 that is screwed onto the valve body 29 and clamps a diaphragm, a notch 33 formed at the free end of the valve body 32 facing the boat 23, and a notch 33 formed around the boat 23. A stepped valve seat 34 is fixed to the stepped portion parallel to the valve seat 34 and is fitted onto the outer periphery of the valve body 32 to divide the chamber 22 into a chamber A facing the boat 23 and a chamber B facing the boat 24. It is composed of a rubber valve seat 35 that is partitioned, and a tapered seal portion 36 formed on the outer peripheral surface of the valve body 32 so that the diameter gradually decreases toward the diaphragm 21. Note that when the seal ring 30 of the fuel control valve 20 is in contact with the valve seat 28, the seal portion 36 of the evaporated fuel control valve 25 is provided so as to be in contact with the valve seat 35. Such a fuel adjustment device connects the third fuel passage 18 (Fig. 2) to the carburetor 2 through the fourth fuel passage 37 as shown in Fig. 1, and connects the boat 23 (Fig. 2) to the vaporized fuel. A guide passage 38 connects the chamber 9 of the canister device 5 (FIG. 1) to the boat 2.
4 (FIG. 2) is connected to the intake manifold 40 of the engine 1 through an evaporated fuel guide passage 39 as shown in FIG.

The operation of the evaporated fuel absorption control device having such a configuration will be explained.

When the lever 19b of the manual cock 19 is set horizontally,
Fuel passages 16 and 17 are blocked.

When starting the engine 1, the lever 19b is directed downward to communicate the fuel passages 16 and 17 through the fuel guide groove 27. When the engine 1 is operated, the negative intake pressure generated in the intake manifold 40 displaces the diaphragm 21 to the right in the figure against the force of the spring 31.

As a result, the valve body 29 of the fuel control valve 20 is separated from the valve seat 28, the fuel passages 17 and 18 are communicated, and the fuel in the fuel tank 4 is sucked into the carburetor 2. The valve body 32 is displaced to the right in FIG. 2, its seal portion 36 is separated from the valve seat 35, and the chambers A and B communicate with each other.
The evaporated fuel collected in the canister device 5 and atmospheric air are drawn into the intake manifold 40 via the evaporated fuel guide passages 38, 39 and the chambers A, B. While the intake negative pressure in the intake manifold 40 is small, the gap between the valve body 32 and the valve seat 34 is sufficiently large, so that the evaporated fuel guide passage 3
The flow rates of evaporated fuel and air taken into the intake manifold 40 through the valve 9 depend on the opening degree of the valve seat 35 and the seal portion 36, and in this case, these flow rates are dependent on the intake negative pressure within the intake manifold 40. increase proportionately. When the intake negative pressure in the intake manifold 40 exceeds a predetermined value, the distance between the valve body 32 and the valve seat 34 affects the flow rate of evaporated fuel and air taken into the intake manifold 40 via the evaporated fuel passage 39. In this case, these flow rates become smaller in proportion to the intake negative pressure in the intake manifold 40. When the intake negative pressure in the intake manifold 40 is very high, for example during idling and deceleration, the valve body 32 comes into contact with the valve seat 34, so that the evaporated fuel and air enter the volume chamber B through the notch 33. After being inhaled by
The fuel is drawn into the intake manifold 40 through the chamber A and the evaporated fuel guide passage 39. In the embodiments described above, the valve seat 35 is made of rubber or the like, but the valve seat 35 may be made of metal and the valve body 32 may be made of a comb or the like. FIG. 3 shows an example of this, in which a rubber valve body 32'' is attached to the shaft 41 screwed to the valve body 29, and a metal valve seat 35'' is attached to the second body 15. good. Furthermore, in the embodiment described above, the valve body 32 is provided with a notch 33 for controlling the flow rate.
3 may be formed on the boat 23 side as shown in FIG. 3, or the boat 23 may be connected to the canister device 5 and the boat 2
4 is connected to the intake manifold 40, but the boat 23 is connected to the intake manifold 40, and the boat 24 is connected to the intake manifold 40.
may be connected to the canister device 5. As explained above, the present invention is equipped with a fuel control valve that controls the fuel from the fuel tank and sends it to the carburetor using the intake negative pressure in the intake manifold, so the fuel passage between the fuel tank and the carburetor is automatically connected. The fuel vapor control valve is provided with a fuel vapor control valve that can be opened and closed automatically, and which controls the flow rate of fuel vapor sucked into the engine from the canister device in conjunction with the fuel control valve. Even if the intake negative pressure of the engine becomes extremely high, the amount of air and evaporated fuel taken into the engine from the canister device is very small, preventing unstable engine operation during idling or deceleration. There is an effect that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram of the evaporated fuel absorption cocitrol device of the present invention, FIG. 2 is a longitudinal sectional view of the fuel regulating device shown in FIG. 1, and FIG. 3 is a diagram showing another embodiment of the fuel regulating device. FIG. 1...engine, 2...carburizer, 4...
... fuel tank, 5 ... canister device,
16, 17, 18, 37...Fuel guide passage, 2
0...Fuel control valve, 25...Evaporative fuel control valve, 32,32''..., valve body, 35,35''...
Valve seat, 38, 39...Evaporative fuel guide passage, 4
0...Intake manifold.

Claims (1)

[Scope of Claims] 1. A fuel passage that guides fuel from a fuel tank to a carburetor, a fuel control valve that opens and closes in the middle of the fuel passage by changing the degree of opening depending on the engine's intake negative pressure, and a fuel control valve that guides fuel from a fuel tank, etc. a canister device for collecting evaporated fuel; a evaporated fuel guide passage connected between the canister device and an intake manifold of the engine;
The fuel vapor control valve is characterized by comprising a fuel vapor control valve that changes the degree of opening in the middle of the fuel vapor guide passage in conjunction with the fuel control valve so that the degree of opening becomes smaller as the degree of opening of the fuel control valve increases. Vaporized fuel absorption control device. 2. In the evaporated fuel absorption control device according to claim 1, either the valve body or the valve seat of the evaporated fuel control valve is made of an elastic material.