JPH0741884Y2 - Carbon canister - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a carbon canister used in an evaporated fuel emission preventing device for an internal combustion engine.

(Prior Art) A carbon canister is inserted at one end and exit 1 as shown in FIG.
An adsorption layer 19 made of activated carbon or the like is provided in a container 16 having 7 and 18 and the other end is opened.
An inner cylinder 20 is provided between the adsorption layer 19 and the adsorption layer 19, and the lower end of the inner cylinder is inserted into the adsorption layer 19, and the evaporated fuel from the fuel tank is introduced from the inlet 17. The adsorption layer 19 is adsorbed and held, and the outside air is introduced from the open end of the container 16 at the time of engine operation to desorb the retained evaporated fuel and let it flow out from the outlet 18.

(Problems to be solved by the invention) In such a carbon canister, when the vaporized fuel reliquefied in the adsorption process flows in from the inlet 17 and is adsorbed to the adsorption layer 19 from the lower end of the inner cylinder 20, However, there is a drawback that the particles are not dispersed in the direction and are not adsorbed, but the adsorption layer mainly under the inner cylinder is mainly adsorbed, the entire adsorption layer is not effectively utilized, and the adsorption amount is reduced. Therefore, a vapor-liquid separator is provided in the vicinity of the fuel tank to reliquefy a part of the evaporated fuel and send only the vaporized fuel to the canister.

However, even by such a separating means, it is not completely liquefied and separated, and it is reliquefied during air supply and flows into the canister. Further, improving the efficiency of the gas-liquid separator results in an increase in cost and an increase in size.

(Means for Solving the Problems) In the carbon canister, a passage communicating with the inlet is provided below the outlet of the container whose lateral portion is open, and the other end of the passage extends above the lower end of the container and is inserted into the adsorption layer. A hole is provided below the upper end of the vertical cross section of the inner cylinder opening of the passage in the lower part of the inner cylinder. A part of the inner cylinder wall is shared so as to surround this hole, and the open end of the passage is A cylinder is provided below the upper end of the vertical section of the inner cylinder opening and inserted into the adsorption layer, and the cylinder is filled with a filter medium.

(Operation) The reliquefied portion of the evaporated fuel flowing from the inlet proceeds to the passage, the inner cylinder, and reaches the inside of the cylinder. Normally, it is gasified by the capillarity of the filter medium in the cylinder and the heat of adsorption generated at the time of adsorption, and is gasified and adsorbed in the adsorption layer.However, when the liquefied component is large, the liquefied component that has flowed in sequentially accumulates in the passage, the inner cylinder and the cylinder. Then, the liquid level is raised and the vertical cross-sectional area of the passage is gradually reduced, but before the passage is filled with liquefied components, it flows out from the open end of the cylinder and flows into the lower part of the adsorption layer.

The vaporized fuel gas flows from the inlet, passes through the upper part of the passage, rises in the inner cylinder, reaches the adsorption layer, and is adsorbed and held.

(Embodiment) FIGS. 1 and 2 show a carbon canister of the present invention, in which an adsorption layer 3 is provided inside a container 1 having inlets and outlets 2 and 11 at one end and laterally opened at the other end. ing. An inner cylinder 4 whose upper end extends into the adsorption layer 3 is provided on an inner wall of a lower end of the container 1, and a passage 5 is provided at a lower end of the inner cylinder one wall. The other end of is communicated with the inlet 2. The inner cylinder 4 has an opening where the passage 5 is penetrated at the lower end of the other wall.
A hole 6 is provided below the upper end of the vertical cross section of 5a, and the other wall of the inner cylinder 4 is arranged outside the other wall of the inner cylinder so that the hole 6 is surrounded and extends above the lower inner wall of the container 1. A cylinder 7 that shares a part of the above and the open end of which is located below the upper end of the vertical cross section of the open portion 5a of the passage 5 and is inserted into the adsorption layer 3 is provided in the cylinder. The filter medium 8 is packed. Filter media 9 and 10 are disposed on the left and right sides of the adsorption layer 3, the stone filter media 9 defines a desorption chamber 12, and the left filter media 10 covers the open end of the other end of the container 1. Adsorption layer 3 in cylinder 4
A central filter medium 13 is provided on the lower surface. Here, the passage 5 may be inclined such that the side communicating with the inlet 2 is located higher than the side communicating with the inner cylinder 4.

FIGS. 3 and 4 show another embodiment of the present invention, and in order to simplify the explanation, parts having the same functions as those in FIGS.

In this embodiment, a part of the other wall of the inner cylinder 4 is shared and inserted into the adsorption layer 3 so as to extend upward from the lower end inner wall of the container 1 and surround the hole 6 outside the other wall of the inner cylinder 4. A tubular body 15 having a plurality of notches 14 extending from the upper end to the lower portion of the vertical cross section of the open portion 5a of the passage 5 is provided, and the tubular filter medium 8 is packed in the tubular body 15. The other structure is exactly the same as that of the above-mentioned embodiment.

In the above embodiment, the reliquefied portion of the evaporated fuel flowing from the inlet 2 flows through the passage 5 and flows into the inner cylinder 4 through the hole 6
The liquefied component that has passed through the cylinder 7 or the cylindrical member 15 is sucked upward by the capillarity of the packed tubular member 8 made of, for example, non-woven fabric, and the vapor component of the vaporized fuel is adsorbed and vaporized by the heat of adsorption to be adsorbed. Adsorbed on 3. When a large amount of liquefied component flows in from the inlet 2 at a time, it flows down sequentially like the normal time and stays in the passage 5, the inner cylinder 4, the cylinder 7 or the cylinder 15 to raise the liquid level. However, before the passage 5 is filled with the liquefied portion, it begins to flow out from the open end of the cylinder 7 or the notches 14 of the cylinder 15. The outflowing liquefied component immediately flows down to the lower part of the adsorption layer 3. When the liquefied component is large, it is more advantageous to provide the passage 5 horizontally in terms of the filling amount. However, when the liquefied component is small, the passage 5 is arranged in an inclined manner in the cylinder 7 for quick storage. To be done.

On the other hand, the gas component of the vaporized fuel flows in through the inlet 2, passes through the upper part of the passage 5, rises in the inner cylinder 4, passes through the central filter medium 13, flows into the adsorption layer 3, and is adsorbed and held in the cylinder 7 or the cylinder 15. The packed tubular filter medium 8 is wet by the liquefied component and has a resistance to allow the gas component to pass therethrough, and therefore does not flow into the barrel 7 or the tubular body 15 through the hole 6.

(Effect of the device) As described above, the carbon canister of the present invention is provided with a passage inside the carbon canister when the evaporated fuel that evaporates from the fuel tank and flows from the inlet of the carbon canister is reliquefied during the adsorption process , A hole is made in the lower part of the inner cylinder that delivers the vaporized fuel gas to the adsorption layer, and it also flows into the cylinder or cylinder provided outside the inner cylinder. Alternatively, since the tubular body has a structure in which the tubular filter medium is packed, the liquefied component that has flowed into the tubular filter or the tubular body is normally sucked up by the capillarity of the tubular filter medium and is absorbed by the heat of adsorption to become a gas again to be adsorbed in the adsorption layer. Therefore, the liquid component does not directly flow into the adsorption layer, and when a large amount of liquid component flows in at one time, a part is leaked out by the notch of the upper end of the cylinder or the cylindrical body to flow down the cylinder or the outer wall of the cylindrical body. Maximum of adsorption layer Only the lower part stays moistened, and only the gas component in the central part of the adsorption layer, which greatly contributes to the adsorption amount, is adsorbed and the adsorption amount does not decrease.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a partial plan view of FIG. 1, FIG. 3 is a sectional view showing another embodiment of the present invention, and FIG. 4 is a sectional view of FIG. FIG. 5 is a partial plan view and FIG. 5 is a sectional view of a conventional carbon canister. 1 ... Container, 2 ... Inlet, 3 ... Adsorption layer 4 ... Inner tube, 5 ... Passage, 5a ... Open part 6 ... Hole, 7 ... Tube, 8 ... Tube filter medium

Claims (1)

[Scope of utility model registration request] 1. An inner cylinder communicating with an inlet through a passage is provided at the lower end of a container having an inlet and an outlet at one end and the other end opened laterally, and an adsorption layer inside. A hole is formed in the lower part of the cylinder below the upper end of the vertical cross section of the inner cylinder opening of the passage, shares a part of the wall surface of the inner cylinder, and the upper end is lower than the upper end of the vertical cross section of the inner cylinder opening of the passage. A carbon canister in which a cylinder that is opened to surround the hole is provided, and a filter medium is disposed in the cylinder.