JPH07293365A - Canister and vapor fuel processing element - Google Patents

Abstract

PURPOSE:To provide activated carbon having good adsorption and desorption characteristics with respect to evaporated fuel. CONSTITUTION:For a canister 1 filled with activated carbon 30 having the ability to adsorb vapor fuel and the ability to desorb adsorbed vapor fuel, an vapor fuel processing bar-like element 26 is made up of a bar-like heat accumulating body 29 having the specific heat larger than that of activated carbon 30, and activated carbone 30 covering the entire surface of the bar heat accumulating body 29, and plural bar elements 26 are packed in a casing 4. The bar heat accumulating bodies 29 restrict the temperature rise of the activated carbon 30 due to adsorption of vapor fuel, and they restrict the temperature decrease of the activated carbon 30 due to desorption of vapor fuel. In this manner, the activated carbone 30 sufficiently exhibits its ability to adsorb and desorb the vapor fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a canister used for treating evaporative fuel in a vehicle or the like, and in particular, an activated carbon having an adsorbing ability for adsorbing the evaporated fuel and a desorbing ability for desorbing the adsorbed evaporated fuel. And a vaporized fuel processing element that is a component thereof.

[0002]

2. Description of the Related Art Generally, the adsorbing ability of activated carbon with respect to vaporized fuel becomes higher as the temperature of the activated carbon becomes lower, while the desorption ability becomes higher as the temperature of the activated carbon becomes higher.

However, since the phenomenon in which the evaporated fuel is adsorbed on the activated carbon is an exothermic reaction, the temperature of the activated carbon rises as the evaporated fuel is adsorbed, and the adsorption capacity of the activated carbon decreases. On the other hand, since the phenomenon in which the evaporated fuel desorbs from the activated carbon is an endothermic reaction, the temperature of the activated carbon lowers as the evaporated fuel desorbs, and the desorption capacity of the activated carbon lowers.

Therefore, as a canister capable of solving such a problem, a canister in which a granular heat storage material having a specific heat larger than that of the activated carbon is mixed has been proposed (for example, JP-A-64-36962). reference).

In this canister, the temperature rise of the activated carbon is suppressed by consuming the heat generated due to the adsorption of the vaporized fuel by the activated carbon to raise the temperature of the heat storage body. By supplying the heat necessary for desorption from the heat storage body, the temperature drop of the activated carbon is suppressed, thereby improving the adsorption-desorption characteristics.

[0006]

However, in the conventional canister, in order to improve its adsorption-desorption characteristics, it is essential that the heat storage bodies are uniformly arranged in the activated carbon. Since the body is composed of metal materials, ceramics, etc., it is very difficult to uniformly mix a large amount of heat storage material with a large amount of activated carbon having a smaller specific gravity in mass production. In such a case, there was a problem that the adsorption-desorption characteristics of each of them were likely to vary and the mass productivity was poor.

In view of the above, it is an object of the present invention to provide the above-mentioned canister, which is capable of uniformly disposing the heat storage body with respect to the activated carbon, and has good mass productivity, and the evaporated fuel processing element which is a component thereof. .

[0008]

The present invention relates to a canister having activated carbon capable of adsorbing vaporized fuel and desorbing the adsorbed vaporized fuel, and has a specific heat storage capacity higher than that of the activated carbon. It is characterized in that a vaporized fuel processing element is constituted by the body and the activated carbon covering the surface of the heat storage body, and a plurality of the elements are filled in the casing.

The present invention is an evaporative fuel treatment element which has an adsorbing ability to adsorb evaporated fuel and a desorbing ability to desorb adsorbed evaporated fuel, and which is a constituent part of a canister. It is characterized by comprising a heat storage body having a large specific heat and the activated carbon covering the surface of the heat storage body.

[0010]

In the canister, the heat storage body is uniformly arranged with respect to the activated carbon simply by filling each element in the casing. As a result, it is possible to avoid variations in the adsorption-desorption characteristics of individual canisters and improve their mass productivity.

Further, in this canister, the heat generated due to the adsorption of the evaporated fuel by the activated carbon is consumed for the temperature rise of the heat storage body, so that the temperature rise of the activated carbon is surely suppressed, while the activated carbon is activated. Since the heat required for desorbing the evaporated fuel from the is supplied from the heat storage body, the temperature drop of the activated carbon is surely suppressed. As a result, the activated carbon sufficiently exhibits the adsorption ability and desorption ability with respect to the evaporated fuel.

By using the element, the productivity of the canister can be greatly improved.

[0013]

1 shows a first example of a canister 1, which is arranged between a fuel tank 2 of a vehicle and an intake pipe 3 of an engine. The canister 1 includes a casing 4, and the casing 4 has a tubular main body 5 and a pair of end walls 6 and 7 closing both ends thereof. The inside of the casing 4 is formed by the two perforated plates 8 and 9 arranged in proximity to the both end walls 6 and 7, and one end wall 6 and the evaporated fuel chamber 10 existing between the one perforated plate 8 and the other end wall. 7 and the other porous plate 9 are divided into an atmospheric chamber 11 and a processing chamber 12 existing between the two porous plates 8 and 9.

First end walls 6 are provided with first and second inflow ports 13 and 14 which open to the evaporated fuel chamber 10. One end of the conduit 15 communicates with the first inlet 13, and the other end of the conduit 15 communicates with the interior of the ceiling wall 16 of the fuel tank 2. The conduit 15 has a one-way valve 17 in its middle portion, and the one-way valve 17 opens when the fuel vapor pressure in the fuel tank 2 exceeds a predetermined value. Further, one end of the conduit 18 communicates with the second inflow port 14, and the other end of the conduit 18 communicates with the inside of the fuel tank 2 in the vicinity of the supply port 19. Conduit 18
Has a switching valve 20 on the side of the supply port 19 thereof, and the switching valve 20 moves in the fuel tank 2 only during the fuel supply.
Connect to 4.

Further, an outflow port 21 opening to the fuel vapor chamber 10 is provided on one end wall 6, one end of a conduit 22 communicates with the outflow port 21, and the other end has a throttle valve 2 in the intake pipe 3.
It communicates with the upstream side of 3. The conduit 22 has an outflow control valve 24 in the middle thereof, and the outflow control valve 24 is the intake pipe 3
Open when the intake negative pressure inside exceeds a specified value.

The atmosphere chamber 11 is opened to the atmosphere through a through hole 25 formed in the other end wall 7.

In the processing chamber 12, a plurality of rod-shaped elements 26 for evaporative fuel treatment, each having a circular cross section, shown in FIG. 2, have one end surface on one porous plate 8 and the other end surface on the other porous plate 9. Filled toward each end, each end face and each porous plate 8,
Filters 27 and 28 are disposed between the filter 9 and the filter 9.

Each element 26 comprises a rod-shaped heat storage body 29 having a circular cross section, and activated carbon 30 covering the entire surface of the heat storage body 29. The rod-shaped heat storage body 29 is made of a material having a larger specific heat than the activated carbon 30, for example, a metal material such as aluminum, an alloy thereof, stainless steel, copper, an alloy thereof, or a ceramic material such as alumina. The activated carbon 30 has an adsorbing ability to adsorb the evaporated fuel and a desorbing ability to desorb the adsorbed evaporated fuel.

In manufacturing the rod-shaped element 26 as described above, the rod-shaped heat storage body 29 is immersed in a mixture of coal powder and a binder (pitch, etc.) to adhere the mixture to the entire surface of the heat storage body 29. Then, the deposition mixture is subjected to carbonization treatment to generate carbon powder, and then the carbon powder is subjected to activation treatment to obtain a rod-shaped element 26 whose entire surface is covered with activated carbon 30.

When the fuel vapor pressure in the fuel tank 2 exceeds a predetermined value while the engine is stopped, the one-way valve 17 opens, so that the evaporated fuel is processed through the conduit 15, the first inlet 13 and the evaporated fuel chamber 10. It flows into the chamber 12. The flow direction of the evaporated fuel in the processing chamber 12 is a direction from one porous plate 8 to the other porous plate 9 as indicated by an arrow a in FIG. 1, and thus is parallel to the axis of each rod-shaped element 26. Therefore, the evaporated fuel smoothly flows through the gap between the adjacent rod-shaped elements 26 and is adsorbed by the activated carbon 30.

During fuel supply, the evaporated fuel generated in the vicinity of the supply port 19 flows into the processing chamber 12 via the switching valve 20, the conduit 18, the second inlet 14 and the evaporated fuel chamber 10, so that the activated carbon is the same as above. Adsorbed by 30.

On the other hand, when the intake negative pressure exceeds a predetermined value during engine operation, the outflow control valve 24 opens, so the evaporated fuel adsorbed by the activated carbon 30 is desorbed from the activated carbon 30 and the direction a On the contrary, it flows in the direction b and flows into the intake pipe 3 through the evaporated fuel chamber 10, the outlet 21 and the conduit 22.

In the canister 1, it is sufficient to fill each of the rod-shaped elements 26 in the casing 4 to activate the activated carbon 3
The rod-shaped heat storage bodies 29 are uniformly arranged with respect to zero. As a result, it is possible to avoid variations in the adsorption-desorption characteristics of the individual canisters 1 and improve their mass productivity.

In the canister 1, the heat generated due to the adsorption of the evaporated fuel by the activated carbon 30 is consumed for the temperature rise of the rod-shaped heat storage body 29, so that the temperature rise of the activated carbon 30 is surely suppressed. On the other hand, activated carbon 3
Since the heat required for desorbing the evaporated fuel from 0 is supplied from the rod-shaped heat storage body 29, the temperature drop of the activated carbon 30 is surely suppressed. As a result, the activated carbon 30 sufficiently exhibits the adsorption ability and desorption ability with respect to the evaporated fuel.

FIG. 3 shows a granular element 31 for treating evaporated fuel.
The granular element 31 is obtained by shredding the rod-shaped element 26 of FIG. 2 along the axial direction thereof, and the granular heat storage body 32 having a circular cross section and its outer peripheral surface (and one end surface) are shown. It consists of activated carbon 30 which covers. The granular elements 31 are randomly packed in the processing chamber 12.

FIG. 4 shows a second example of the canister 1. Each element 33 in this canister 1 has a flat mesh shape, and these mesh elements 33 are stacked in the processing chamber 12 so that both surfaces thereof intersect the flow directions a and b of the evaporated fuel in the processing chamber 12. Filled with.

As clearly shown in FIG. 5, the mesh element 3
3 comprises a flat reticulated heat storage body 34 and activated carbon 30 which covers the surface of the reticulated heat storage body 34 so that a mesh 35 remains. The material of the reticulated heat storage body 34 is the same as that of the rod-shaped heat storage body 29, and the reticulated element 33 is manufactured by the same method as the rod-shaped element 26. The other components in FIG. 4 that are the same as those in FIG. 1 are assigned the same reference numerals as those in FIG. 1 and description thereof is omitted.

With the above construction, the reticulated heat storage material 34 suppresses the temperature rise of the activated carbon 30 during adsorption of the evaporated fuel and the temperature reduction of the activated carbon 30 during the desorption of the evaporated fuel.

Further, in the processing chamber 12, a flow of the evaporated fuel is formed through the mesh 35 of each mesh element 33, so that the adsorption of the evaporated fuel by the activated carbon 30 and the desorption of the evaporated fuel from the activated carbon 30 are efficiently performed. .

FIG. 6 shows a third example of the canister 1, in which the plurality of reticulated elements 33 are provided.
Are buried in the activated carbon 30 filled in the processing chamber 12. Both sides of each reticulated element 33 are the processing chamber 1
There is a predetermined space c between the two reticulated elements 33 which are arranged so as to intersect with the flow directions a and b of the evaporated fuel in 2 and are adjacent to each other. The other components in FIG. 6 which are the same as those in FIG. 1 are assigned the same reference numerals as those in FIG. 1 and their description is omitted.

Also with the above structure, the reticulated heat storage body 34 suppresses the temperature rise of the activated carbon 30 at the time of adsorbing the evaporated fuel and the temperature decrease of the activated carbon 30 at the time of desorbing the evaporated fuel. The activated carbon 30 includes activated carbon that is a constituent element of the mesh element 33 and activated carbon around the mesh element 33.

FIG. 7 shows a fourth example of the canister 1. In this canister 1, a plurality of reticulated heat storage bodies 32 are embedded in the activated carbon 30 filled in the processing chamber 12. Each of the reticulated heat storage bodies 32 is arranged so that both surfaces thereof intersect the flow directions a and b of the evaporated fuel in the processing chamber 12, and a predetermined space c exists between the two reticulated heat storage bodies 32 adjacent to each other. . The other components in FIG. 7 which are the same as those in FIG. 1 are assigned the same reference numerals as those in FIG. 1 and their description is omitted.

With the above structure, the reticulated heat storage 34 suppresses the temperature rise of the activated carbon 30 at the time of adsorbing the evaporated fuel and the temperature decrease of the activated carbon 30 at the time of desorbing the evaporated fuel.

FIG. 8 shows a fifth example of the canister 1. This canister 1 includes a casing 4, and the casing 4
Is a tubular main body 5 and a pair of end walls 6 and 7 for closing both ends thereof.
Have and. The interior of the casing 4 is divided into a large volume first region 37 and a small volume second region 38 by a partition plate 36 extending from one end wall 6 to the other end wall 7, but both regions 37 are formed. , 38 communicate with each other through an opening 39 between the tip edge of the partition plate 36 and the inner surface of the other end wall 7.

In each region 37, 38, one end wall 6
Perforated plates 8 ₁ and 8 ₂ are arranged in close proximity to each other.
Further, a perforated plate 9 is disposed in proximity to the other end wall 7 so as to extend over both regions 37, 38, and the perforated plate 9 is the partition plate 3
Close to the leading edge of No. 6.

As a result, in the first region 37, the evaporative fuel chamber 10 is defined between the _one end wall 6 and the porous plate 8 ₁ , and the main processing chamber 12 ₁ is defined between the porous plates 8 ₁ and 9. . On the other hand, in the second region 38, the atmosphere chamber 11 is provided between the one end wall 6 and the perforated plate 8 ₂ and both the perforated plates 8 ₂ and 9 are provided.
Sub-processing chambers 12 ₂ are defined between them. Further, a communication chamber 40 is defined between the other end wall 7 and the porous plate 9, and the main and sub processing chambers 12 ₁ and 12 ₂ communicate with each other through the communication chamber 40.

The evaporative fuel chamber 1 is formed on one end wall 6 in the same manner as described above.
The first and second inlets 13 and 14 and the outlet 21 that open at 0
Are provided, and these 13, 14, and 21 are connected to the fuel tank 2 and the intake pipe 3 in the same manner as described above. Atmosphere chamber 11
Is opened to the atmosphere through a through hole 25 formed in one end wall 6.

The main and sub processing chambers 12 ₁ and 12 ₂ are filled with a plurality of mesh elements 33 similar to the above in a laminated state as described above. 27 ₁ , 27 ₂ , 28 ₁ and 28 ₂ are filters.

According to this canister 1, the main processing chamber 12
_{When the} adsorbed amount of evaporated fuel in ₁ is saturated, the adsorbed fuel can be further adsorbed by the sub-processing chamber 12 ₂ .

[0040]

EFFECTS OF THE INVENTION According to the present invention, by having the above-mentioned constitution, it is possible to provide a canister in which a heat storage material is uniformly arranged with respect to activated carbon, whereby the adsorption-desorption characteristic in each canister is provided. It is possible to improve the mass productivity by avoiding the variation of Moreover, the canister having the heat storage bodies uniformly arranged has excellent adsorption-desorption characteristics.

Further, according to the present invention, it is possible to provide an evaporated fuel processing element which can improve the productivity of the canister.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a first example of a canister arranged between a fuel tank and an intake pipe.

FIG. 2 is a fragmentary perspective view showing a rod-shaped element for processing evaporated fuel.

FIG. 3 is a perspective view of a granular element for processing evaporated fuel.

FIG. 4 is a vertical sectional front view showing a second example of a canister.

FIG. 5 is an enlarged plan view of a broken portion of a main part of a mesh element for processing evaporated fuel.

FIG. 6 is a vertical sectional front view showing a third example of a canister.

FIG. 7 is a vertical sectional front view showing a fourth example of a canister.

FIG. 8 is a vertical sectional front view showing a fifth example of a canister.

[Explanation of symbols]

 1 Canister 4 Casing 26 Rod-shaped element 29 Rod-shaped heat storage body 30 Activated carbon 31 Granular element 32 Granular heat storage body 33 Reticulated element 34 Reticulated thermal storage body 35 Mesh

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yama ▲ saki ▼ Kazumi 1-4-1, Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (72) Inventor Tomoyuki Kawakami Hagadai, Haga-cho, Haga-gun, Tochigi Prefecture No. 143 Within PGS Co., Ltd.

Claims (10)

[Claims] 1. An activated carbon (30) having an adsorption capacity for adsorbing vaporized fuel and a desorption capacity for desorbing the adsorbed vaporized fuel.
In a canister provided with a heat storage body (29, 32, 34) having a larger specific heat than the activated carbon (30), and the activated carbon (3) covering the surface of the heat storage body (29, 32, 34).
0) and the evaporative fuel treatment element (26, 31, 3)
3), and a plurality of the elements (26, 31, 3)
A canister, characterized in that the casing (4) is filled with 3). 2. Each element (26) is rod-shaped, said elements (26) being arranged such that their axes are parallel to the flow direction (a, b) of the fuel vapor within said casing (4). Arranged in (4),
The canister according to claim 1. 3. Each element (33) has a flat mesh shape, and both sides of each element (33) of the element (33) flow direction (a, a) of the evaporated fuel in the casing (4).
The canister according to claim 1, wherein the canister is arranged in a stacked state in the casing (4) so as to intersect with b). 4. The element (31) has a granular shape,
Canister according to claim 1, characterized in that the elements (31) are arranged at random in the casing (4). 5. An activated carbon (30) having an adsorption ability to adsorb evaporated fuel and a desorption ability to desorb adsorbed evaporated fuel.
In a canister in which the casing (4) is filled with
A flat reticulated heat storage body (34) having a larger specific heat than that of the activated carbon (30) and the same activated carbon (30) covering the surface of the heat storage body (34) so that the mesh (35) remains. And more than one element for processing evaporated fuel (3
3), and these elements (33) have their both surfaces intersecting with the flow directions (a, b) of the evaporated fuel in the casing (4) and have a space () between the two adjacent elements (33). A canister, characterized in that it is embedded in the activated carbon (30) in the presence of c). 6. An activated carbon (30) having an adsorption ability to adsorb evaporated fuel and a desorption ability to desorb adsorbed evaporated fuel.
In a canister in which the casing (4) is filled with
A plurality of heat storage bodies (34), which have a specific heat larger than that of the activated carbon (30) and have a flat mesh shape, have their both sides on the flow direction (a, a) of the evaporated fuel in the casing (4).
A canister, characterized in that it is embedded in the activated carbon (30) with a space (c) between both heat storage bodies (34) adjacent to each other while intersecting with b). 7. An evaporative fuel treatment element, which has an adsorbing ability to adsorb evaporated fuel and a desorbing ability to desorb adsorbed evaporated fuel, and is a constituent part of a canister (1), comprising activated carbon ( 30) which has a larger specific heat than the heat storage body (2
9, 32, 34) and its heat storage body (29, 32, 34)
An evaporative fuel treatment element comprising the activated carbon (30) covering the surface of the fuel vapor. 8. The evaporative fuel treatment element according to claim 7, wherein the heat storage body (29) has a rod shape. 9. The heat storage body (34) has a flat mesh shape, and the activated carbon (30) covers the surface of the heat storage body (34) so that a mesh (35) remains. Evaporative fuel processing element. 10. The evaporative fuel treatment element according to claim 7, wherein the heat storage body (32) has a granular shape.