JPH0734985A - Evaporative fuel adsorption device for small general-purpose engine - Google Patents

Abstract

(57) [Summary] [Purpose] To simplify the mounting structure of the evaporative fuel adsorbent for small general-purpose engines and to reduce the mounting space. [Structure] Inside a lid 8 of a fuel inlet 3 of a fuel tank 2 of a small-sized general-purpose engine 1, an evaporative fuel adsorbing chamber 9 is provided on an upper side to accommodate an evaporative fuel adsorbent 7a, and a gas-liquid separating chamber is disposed on the lower side thereof. 10 is provided so that the vaporized fuel flow pipe 11 penetrates through the central portions of the vaporized fuel adsorption chamber 9 and the gas-liquid separation chamber 10 to communicate with each other. A packing pressing spring 12 is provided in the gas-liquid separation chamber 10, and the packing 13 at the sealing portion of the fuel injection port 3 is pressed to be hermetically sealed. A fuel liquid cutoff plate 14 that fits in the fuel injection port 3 and is slidable is fixed to the lower end of the evaporated fuel flow pipe 11, and a float valve 15 is provided in an evaporated fuel flow hole 14a opened in the fuel liquid cutoff plate 14. It is provided so that only the evaporated fuel flows into the gas-liquid separation chamber 10 through the evaporated fuel flow hole 14a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporated fuel adsorbing device for a small general-purpose engine.

[0002]

2. Description of the Related Art In the prior art, there is an evaporative fuel adsorbing device for a small-sized general-purpose engine, for example, as shown in FIG. That is, the evaporated fuel discharge port 4 is opened in the fuel inlet 3 of the fuel tank 2 of the small general-purpose engine 1, and the evaporated fuel discharge port 4 is connected to the intake system 6 of the engine 1 by the evaporated fuel discharge pipe 5. An evaporative fuel adsorption container 7 is disposed between the fuel injection port 3 and the air supply system 6 to accommodate the evaporative fuel adsorbent 7a so as to adsorb the evaporative fuel evaporated from the fuel tank 2. It is composed. Reference numeral 8 in the drawing is a lid of the fuel inlet 3.
Reference numeral 16 is an air cleaner, reference numeral 20 is a carburetor, and reference numeral 21.
Is an intake passage, and reference numeral 22 is a combustion chamber.

[0003]

The above-mentioned conventional techniques have the following problems. Since the evaporative fuel adsorption device is independent as the evaporative fuel adsorption container 7 that accommodates the evaporative fuel adsorbent 7a between the fuel inlet 3 and the air supply system 6, its mounting space, mounting parts, etc. are extra. It will be necessary and costly. An object of the present invention is to improve the adsorption amount and adsorption rate while simplifying the mounting structure of the evaporated fuel adsorbent to reduce the mounting space.

[0004]

In order to achieve the above object, the present invention has the following improvements in the above prior art, as shown in FIGS. 1 and 2, for example. First invention (see FIG. 1) Within the lid 8 of the fuel inlet 3 of the fuel tank 2 of the small general-purpose engine 1, the vaporized fuel adsorption chamber 9 is provided on the upper side and the gas-liquid separation chamber 10 is provided on the lower side thereof. . The vaporized fuel adsorbent 7a is accommodated in the vaporized fuel adsorption chamber 9, and the vaporized fuel flow pipe 11 is provided at the center of the vapor-liquid separation chamber 10 so that the vaporized fuel adsorption chamber 9 and the vapor-liquid separation chamber 10 can be accommodated. And to communicate with. Further, a packing pressing spring 12 is provided in the gas-liquid separation chamber 10, and the packing 13 is provided at the sealing portion of the fuel injection port 3 by the packing pressing spring 12.
It is configured so that it can be sealed by pressing. Then, a fuel liquid cutoff plate 14 which is fitted into the fuel injection port 3 and is slidable is fixed to the lower end of the evaporated fuel flow pipe 11, and an evaporated fuel flow hole 14a opened in the fuel liquid cutoff plate 14 is formed. Is provided with a float valve 15 and only the evaporated fuel is allowed to flow into the gas-liquid separation chamber 10 through the evaporated fuel flow hole 14a. Second invention (see FIG. 2) The evaporated fuel adsorbent 7a is housed in the purified air outlet chamber 17 of the air cleaner 16 of the intake system 6 of the small general-purpose engine 1, and the evaporated fuel exhaust pipe 5 is connected to the purified air outlet chamber. Inside of 17, it is connected to the upstream side 17a of the evaporated fuel adsorbent 7a. Then, an air vent hole 19 provided with a check valve 18 is opened in the purified air outlet chamber 17 on the downstream side 17b of the evaporated fuel adsorbent 7a.

[0005]

The present invention operates as follows. First invention (see FIG. 1) The liquid fuel 23 in the fuel tank 2 evaporates to form evaporated fuel gas, and the evaporated fuel flow is opened in the slidable fuel liquid blocking plate 14 fitted in the fuel inlet 3 After passing through the hole 14a, the fuel flows into the gas-liquid separation chamber 10 provided below the lid 8 of the fuel inlet 3. Since the inside of the gas-liquid separation chamber 10 is sealed by pressing the packing 13 provided in the sealing portion of the fuel injection port 3 with the packing pressing spring 12, the evaporated fuel gas is contained in the gas-liquid separation chamber 10. Through the inside of the vaporized fuel flow pipe 11 having a large number of small holes, and flows into the vaporized fuel adsorption chamber 9 on the upper side in the lid 8 which communicates through the vaporized fuel flow pipe 11. Further, in the evaporated fuel adsorption chamber 9, a part of the evaporated fuel gas is evaporated fuel adsorbent 7a.
And the rest is sucked into the clean air outlet chamber 17 of, for example, the air cleaner 16 of the intake system 6 of the engine 1 through the evaporated fuel discharge port 4 opened at the upper portion of the lid 8 and the evaporated fuel discharge pipe 5. Since the float valve 15 is provided in the evaporative fuel flow hole 14a opened in the fuel liquid cutoff plate 14, even if the liquid fuel 23 is excessively injected, the float valve 15 is pushed up by the liquid fuel 23 and the above-mentioned. In addition to closing the vaporized fuel flow hole 14a, the vaporized fuel flow pipe 11 penetrates the vaporized fuel adsorption chamber 9 and the gas-liquid separation chamber 10 at the center of the vapor-liquid separation chamber 10. Even if tilted, it prevents the vaporized fuel adsorbent 7a from being immersed in the liquid fuel 23 from any direction, and there is little risk that the adsorption performance of the vaporized fuel will deteriorate.

Second Invention (See FIG. 2) The liquid fuel 23 in the fuel tank 2 evaporates into evaporated fuel gas, and the air cleaner 16 is discharged from the evaporated fuel discharge port 4 opened above the lid 8 of the fuel inlet 3. Through the evaporative fuel discharge pipe 5 communicating with the upstream side 17 a in the purified air outlet chamber 17 of the above. When the engine 1 is stopped, it is adsorbed by the evaporated fuel adsorbent 7a in the purified air outlet chamber 17 and flows out through the check valve 18 from the air vent hole 19 opened on the downstream side 17b of the evaporated fuel adsorbent 7a. However, when the engine 1 is in operation, the check valve 18 is closed by the negative pressure of the air cleaner 16. In the present invention, the first
Since the sectional area of the vaporized fuel adsorbent 7a can be made larger than that of the invention, the adsorption amount and adsorption rate can be improved.

[0007]

The present invention has the following effects because it is constructed and operates as described above. The evaporated fuel adsorbent 7a is housed in an evaporated fuel adsorbing chamber 9 provided in the lid 8 of the fuel injection port 3 of the fuel tank 2 so that the evaporated fuel gas is adsorbed by the evaporated fuel adsorbent 7a. Therefore, an extra mounting space for the evaporated fuel adsorbing container 7, a mounting part, and the like are unnecessary, and the mounting structure of the evaporated fuel adsorbent can be simplified and the mounting space can be reduced. Furthermore, the evaporated fuel adsorbent 7
When a is housed in the air purifying outlet chamber 17 of the air cleaner 16 and has a large cross-sectional area, the adsorption amount and adsorption rate can be improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First embodiment of the invention (see FIG. 1) FIG. 1 is a cross-sectional system diagram of essential parts of an evaporated fuel adsorbing device for a small general-purpose engine. In the figure, an evaporated fuel discharge port 4 is opened above the lid 8 of the fuel injection port 3 of the fuel tank 2 of the small general-purpose engine 1, and the evaporated fuel discharge port 4 is connected to the evaporated fuel discharge pipe 5.
Thus, the intake system 6 of the engine 1 is communicated with, for example, the purified air outlet chamber 17 downstream of the cleaner element 16a of the air cleaner 16. Then, in the lid 8 of the fuel inlet 3 of the fuel tank 2, the evaporated fuel adsorption chamber 9 is provided on the upper side to form the evaporated fuel adsorption container 7, and the gas-liquid separation chamber 10 is provided on the lower side thereof. I am doing it. Further, for example, activated carbon as the evaporated fuel adsorbent 7a is accommodated in the evaporated fuel adsorption chamber 9 to adsorb evaporated fuel evaporated from the fuel tank 2, and an evaporated fuel flow pipe 11 having a large number of small holes. At the central portion of the gas-liquid separation chamber 10 so as to penetrate the vaporized fuel adsorption chamber 9 and the gas-liquid separation chamber 10 to communicate with each other. Then, a packing pressing spring 12 is provided in the gas-liquid separation chamber 10, and the packing pressing spring 12 is provided.
Then, the packing 13 provided in the sealing portion of the fuel injection port 3 is pressed to be hermetically sealed. Further, a fuel liquid cutoff plate 14 which is slidably fitted in the fuel injection port 3 is fixed to the lower end of the evaporated fuel flow pipe 11, and an evaporated fuel flow hole 14a opened in the fuel liquid cutoff plate 14 is formed. Is provided with a float valve 15 so that only the evaporated fuel flows into the gas-liquid separation chamber 10 through the evaporated fuel flow hole 14a. Reference numeral 20 is a carburetor, reference numeral 21 is an intake passage, reference numeral 22 is a combustion chamber, and reference numeral 23 is liquid fuel such as gasoline.

Second Embodiment of Invention (See FIG. 2) FIG. 2 is a view corresponding to FIG. The evaporated fuel adsorbent 7a is accommodated in the purified air outlet chamber 17 of the air cleaner 16 of the intake system 6 of the small general-purpose engine 1, and the evaporated fuel discharge pipe 5 is connected to the evaporated fuel in the purified air outlet chamber 17. It is connected to the upstream side 17a of the adsorbent 7a. And
An air vent hole 19 provided with a check valve 18 is opened in the purified air outlet chamber 17 on the downstream side 17b of the evaporated fuel adsorbent 7a.

[Brief description of drawings]

FIG. 1 is a sectional view showing the essential parts of an evaporated fuel adsorbing device for a small general-purpose engine according to a first embodiment of the invention.

FIG. 2 is a diagram corresponding to FIG. 1, showing a second embodiment of the invention.

FIG. 3 is a system diagram of an evaporated fuel adsorbing device for a small general-purpose engine, showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Small general-purpose engine, 2 ... Fuel tank, 3 ... Fuel injection port, 4 ... Evaporative fuel discharge port, 5 ... Evaporative fuel discharge pipe, 6 ... Intake system, 7 ... Evaporative fuel adsorption container, 7a ... Evaporative fuel adsorbent, 8 ... Lid, 9 ... Evaporative fuel adsorption chamber, 10 ... Gas-liquid separation chamber, 11 ... Evaporative fuel flow pipe, 12 ...
Packing pressure spring, 13 ... Packing, 14 ... Fuel liquid blocking plate, 14a ... Evaporative fuel flow hole, 15 ... Float valve, 1
6 ... Air cleaner, 17 ... Purification outlet chamber, 17a ... Upstream side, 17b ... Downstream side, 18 ... Check valve, 19 ... Air vent hole.

Claims (2)

[Claims] 1. A fuel tank (2) for a small general-purpose engine (1)
The fuel vapor inlet (3) of the engine is opened with the fuel vapor outlet (4), and the fuel vapor outlet (4) is connected to the intake system (6) of the engine (1) by the fuel vapor discharge pipe (5). The evaporated fuel adsorption container (7) is disposed between the fuel inlet (3) and the air supply system (6) to accommodate the evaporated fuel adsorbent (7a), In the evaporative fuel adsorbing device for a small general-purpose engine configured to adsorb evaporative fuel that evaporates, in the lid (8) of the fuel inlet (3) of the fuel tank (2), the evaporative fuel adsorbing chamber (9 ) Is provided and a gas-liquid separation chamber (10) is provided below it, and the vaporized fuel adsorbent (7a) is provided in the vaporized fuel adsorption chamber (9).
And the vaporized fuel flow pipe (11) at the center of the gas-liquid separation chamber (10) for adsorbing the vaporized fuel.
And a gas-liquid separation chamber (10) so as to penetrate therethrough, and a packing pressing spring (12) is provided in the gas-liquid separation chamber (10).
A fuel liquid cutoff plate that is slidable by pressing a packing (13) provided in the sealing portion of (3) so as to be hermetically sealed and fitted in the fuel injection port (3).
(14) is fixed to the lower end of the vaporized fuel flow pipe (11), and a float valve (15) is provided in the vaporized fuel flow hole (14a) opened in the fuel liquid cutoff plate (14) to vaporize the vaporized fuel. An evaporated fuel adsorbing device for a small general-purpose engine, characterized in that only evaporated fuel is allowed to flow into the gas-liquid separation chamber (10) through the fuel flow hole (14a). 2. A fuel tank (2) for a small general-purpose engine (1)
The fuel vapor inlet (3) of the engine is opened with the fuel vapor outlet (4), and the fuel vapor outlet (4) is connected to the intake system (6) of the engine (1) by the fuel vapor discharge pipe (5). The evaporated fuel adsorption container (7) is disposed between the fuel inlet (3) and the air supply system (6) to accommodate the evaporated fuel adsorbent (7a), In an evaporative fuel adsorbing device for a small general-purpose engine configured to adsorb evaporative fuel that evaporates, a purified air outlet chamber (1) of an air cleaner (16) of the intake system (6) is provided.
7) The vaporized fuel adsorbent (7a) is housed inside, and the vaporized fuel discharge pipe (5) is connected to the purified air outlet chamber (17).
Inside the air purification outlet chamber (17), an air vent hole (19) provided with a check valve (18) is connected to the upstream side (17a) of the fuel vapor adsorbent (7a). Downstream of agent (7a) (1
7b) is an opening for an evaporated fuel adsorbing device for a general-purpose small engine.