JP2005325708A - Canister - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a canister for improving collecting performance by sufficiently restraining a temperature change even in a small type. <P>SOLUTION: In this canister, the inside of a vessel 1 is divided into a main chamber 6 and an auxiliary chamber 8, and are mutually communicated. The main chamber 6 is provided with an inflow port 16 for introducing fuel vapor and an outflow port 18 for exhausting separated fuel to an intake pipe of an internal combustion engine. The auxiliary chamber 8 is provided with an introducing port 26 for introducing air. The fuel vapor introduced from the inflow port 16 is adsorbed in adsorbents 42 and 50. and the fuel adsorbed in the adsorbents 42 and 50 is separated by the air introduced from the introducing port 26. The main chamber 6 is filled with a capsule 44 containing a heat accumulating material for adsorbing or releasing heat by a phase change together with the adsorbent 42. The adsorbent 50 filled in the auxiliary chamber 8 is molded from powdery activated carbon. The adsorbent 50 is formed in a shape of shortening a distance up to the inside activated carbon from a surface of the adsorbent 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a canister for adsorbing and processing fuel vapor generated in a fuel tank or the like of an automobile on an adsorbent.

Conventionally, as disclosed in Patent Document 1, an activated carbon layer made of pellet-like activated carbon and a heat storage layer made of pellet-like heat accumulation body having a larger thermal conductivity and specific heat than activated carbon alternately in the container of the canister, A multi-layered arrangement has been proposed. As a result, the fuel vapor introduced into the container is adsorbed by the activated carbon, and the heat generated during the adsorption is absorbed by the heat accumulator, thereby suppressing the temperature rise and preventing the adsorption capacity from being lowered. In addition, the fuel adsorbed by the activated carbon is desorbed by introducing air into the container during operation of the internal combustion engine, and temperature drop during the desorption is prevented by taking heat away from the heat storage body. It was.
JP-A-9-112356

  However, in such a conventional apparatus, the heat generated during the adsorption of the fuel vapor is absorbed by the temperature increase of the heat storage body, and when the adsorbed fuel is desorbed, the activated carbon takes heat from the heat storage body due to the temperature decrease of the heat storage body. Since the temperature change of the activated carbon is prevented by the heat absorption and heat release due to the temperature change according to the specific heat of the heat storage body, the temperature of the heat storage body changes with the heat absorption and heat release, and the temperature of the activated carbon also changes accordingly. However, there has been a problem that the decrease in adsorption / desorption performance cannot be sufficiently suppressed. Moreover, when trying to reduce the temperature change, there is a problem that a large amount of heat storage body must be filled.

  In addition, a cylindrical pellet having a diameter of 2 mm and a length of about 3 to 4 mm, or a spherical pellet of activated carbon having a diameter of about 2 to 3 mm is used. Although the fuel penetrates to the center, when the fuel is desorbed from the pellet-like activated carbon, there is a problem that the desorption of the fuel near the center does not proceed and the fuel remains near the center. In particular, in a canister having a structure in which the inside of the container is divided into a main chamber and a sub chamber and discharged into the atmosphere through the sub chamber, fuel vapor that could not be adsorbed in the main chamber is adsorbed in the sub chamber and Is not released. If desorption from the activated carbon in the sub chamber is not sufficient, there is a problem that residual vapor may be released to the atmosphere.

  An object of the present invention is to provide a canister that can sufficiently suppress a temperature change and can improve the collection performance even if it is small.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
A container filled with an adsorbent is provided, and the inside of the container is divided into a main chamber and a sub chamber, and communicates with each other. An outflow port for discharging to the intake pipe of the engine, and an introduction port for introducing air into the sub chamber, and adsorbing fuel vapor introduced from the inflow port to the adsorbent, and from the introduction port In the canister for desorbing the fuel adsorbed on the adsorbent by the introduced air,
The main chamber is filled with a capsule containing a heat storage material that absorbs and dissipates heat by phase change together with the adsorbent, and the adsorbent filled in the sub chamber is formed from powdered activated carbon. In addition, the canister is characterized in that the adsorbent is formed in a shape in which the distance from the surface of the adsorbent to the activated carbon inside is shortened.

  The heat storage material may absorb heat and release heat by phase change between a solid phase and a liquid phase. The capsule may contain the heat storage material with a heat-resistant resin. The sub chamber may be further filled with a heat storage material having a large heat capacity. Alternatively, the sub chamber may be further filled with a capsule containing a heat storage material that absorbs and dissipates heat by phase change.

  Since the canister of the present invention is filled with a capsule containing a heat storage material that absorbs and dissipates heat by phase change, the temperature change of the main chamber can be sufficiently suppressed even in a small size, and the adsorbent in the sub chamber is an adsorbent Since the distance from the surface to the activated carbon inside is shortened, the fuel is desorbed quickly, the adsorption is recovered quickly, and the collection performance can be improved.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, reference numeral 1 denotes a canister container, and the container 1 is made of a synthetic resin. One of the containers 1 is open and is closed by a lid member 2. In the present embodiment, the container 1 is partitioned by a partition wall 4 to form a main chamber 6 and a sub chamber 8. The volume of the main chamber 6 is larger than the volume of the sub chamber 8, and the sub chamber 8 is formed in an elongated shape. The main chamber 6 and the sub chamber 8 are communicated with each other through a communication passage 10 formed on the lid member 2 side.

  As shown in FIG. 4, an inflow port 16 connected to the fuel tank 12 via a check valve 14 is formed in the container 1 on the side opposite to the lid member 2. The inflow port 16 is connected to the main chamber 6 so that fuel vapor from the fuel tank 12 can be introduced.

  In addition, an outflow port 18 is formed in the container 1 along with the inflow port 16, and the outflow port 18 is connected to an intake pipe 22 of the internal combustion engine 20 via a purge valve 24. The outflow port 18 is connected to the main chamber 6 and is configured to be able to discharge desorbed fuel, which will be described later, to the intake pipe 22 via the purge valve 24. Further, the container 1 is formed with an introduction port 26 communicating with the atmosphere side, and the introduction port 26 is connected to the sub chamber 8. The introduction port 26 is configured so that air from the atmosphere side can be introduced into the sub chamber 8.

  In the main chamber 6, filters 28 and 30 are provided at the ends on the inflow port 16 and outflow port 18 side, and a filter 32 is also provided on the end on the lid member 2 side. In the sub chamber 8, a filter 34 is provided at the end on the introduction port 26 side, and a filter 36 is provided also on the end on the lid member 2 side. The filters 32 and 36 on the lid member 2 side are respectively provided with porous plates 38 and 40, and coil springs 41 a and 41 b are interposed between the porous plates 38 and 40 and the lid member 2, respectively. ing.

  The main chamber 6 is filled with an adsorbent 42 and a capsule 44 between the filters 28 and 30 on the inflow port 16 and outflow port 18 side and the filter 32 on the lid member 2 side. In this embodiment, the adsorbent 42 is a pellet formed by kneading granular activated carbon together with a binder into a cylindrical shape having a diameter of about 1 to 3 mm and a length of about 3 to 10 mm. As shown in FIG. 2, the capsule 44 includes a heat storage material 48 in a coating 46 and is formed in a substantially spherical shape. In this embodiment, the coating 46 is made of a heat-resistant resin, and the coating 46 has a heat resistance of about 120 ° C. so that it can withstand the temperature rise due to heat generated when the fuel vapor is adsorbed to the adsorbent 42. It is preferable to have.

  The heat storage material 48 is a substance that melts and solidifies with a melting point / freezing point around 25 to 35 ° C., that is, a substance that changes from a solid phase to a liquid phase and a phase change from a liquid phase to a solid phase. A material that absorbs heat or dissipates heat is used. The reason why the melting point / freezing point is about 25 to 35 ° C. is that the temperature at which the adsorbent 42 adsorbs the fuel vapor or desorbs the fuel is used in the vicinity of the canister mounted on the automobile.

  As shown in FIG. 1A, an adsorbent 42 in which activated carbon is formed in a columnar shape and a capsule 44 are mixed, and the capsule 44 is coated on the surface of the adsorbent 42 and filled into the main chamber 6. Alternatively, as shown in FIG. 1 (B), the activated carbon and the capsule 44 are mixed to form a cylindrical adsorbent 42 together with the capsule 44, and this is formed into the main chamber 6. You may make it fill with.

  A plurality of types of capsules 44 having different melting points and freezing points of the heat storage material 48 may be used. For example, both the capsule 44 of the heat storage material 48 having a melting point / freezing point of 25 ° C. and the capsule 44 of the heat storage material 48 having a melting point / freezing point of 35 ° C. are filled in the main chamber 6 together with the adsorbent 42. May be. In this embodiment, the latent heat due to the phase change between the solid phase and the liquid phase of the heat storage material 48 of the capsule 44 is used. However, the present invention is not limited to this, and the latent heat due to the phase change between the liquid phase and the gas phase may be used. .

  In the sub chamber 8, an adsorbent 50 is filled between the filter 34 on the introduction port 26 side and the filter 36 on the lid member 2 side. In this embodiment, the adsorbent 50 is a pellet formed by kneading granular activated carbon together with a binder and having a diameter of about 1 to 3 mm and a length of about 3 to 10 mm.

  Further, unlike the adsorbent 42 in the main chamber 6, the adsorbent 50 is formed in a shape in which the distance from the surface of the adsorbent 50 to the internal activated carbon is shortened as shown in FIG. 3. When forming the shape with a short distance to the activated carbon inside, the distance to the activated carbon inside may be shortened by forming the inside hollow to increase the apparent surface area, or unevenness on the surface May be provided so as to increase the surface area on the appearance and shorten the distance to the activated carbon inside.

  For example, as shown in FIG. 3 (a), the interior may be formed into a hollow cylindrical shape, and the distance to the activated carbon inside may be shortened by increasing the surface area. Further, as shown in FIG. 3 (b), it may be formed into a columnar shape and formed so as to have a large number of small holes, and the surface area may be increased to shorten the distance to the activated carbon inside.

  Further, as shown in FIG. 3C, the outer shape may be formed into a columnar shape and the inside may be formed into a honeycomb shape to increase the surface area and shorten the distance to the activated carbon inside. Alternatively, as shown in FIG. 3 (d), a number of depressions may be formed on the surface formed into a columnar shape to increase the surface area and shorten the distance to the activated carbon inside. Further, as shown in FIG. 3 (e), it may be formed into a shape in which a large number of protrusions protrude to increase the surface area and shorten the distance to the internal activated carbon. By forming the distance to the internal activated carbon short, the fuel is easily desorbed when the air introduced into the sub chamber 8 described later touches the surface of the adsorbent 50. That is, the distance from the surface of the adsorbent 50 to each granular activated carbon is shortened, and fuel is desorbed quickly.

  Further, the sub chamber 8 may be filled with the adsorbent 50 and the heat storage material using charcoal having a large heat capacity in a uniformly dispersed manner. The heat storage material uses charcoal with a high density. Alternatively, the above-described capsule 44 may be uniformly dispersed and filled in the sub chamber 8 instead of the heat storage material using the charcoal.

Next, the operation of the canister of this embodiment described above will be described.
First, when the automobile is stopped without operating the internal combustion engine 20, fuel vapor generated in the fuel tank 12 or the like is introduced into the main chamber 6 via the inflow port 16. The introduced fuel vapor passes through the filter 28 and is adsorbed by the adsorbent 42 in the main chamber 6. When the fuel vapor becomes a liquid fuel and is adsorbed on the adsorbent 42, heat is generated.

  In the present embodiment, when the temperature rises due to this heat generation and reaches a melting point near 25 to 35 ° C., heat absorption is performed by melting the heat storage material 48 from the solid phase to the liquid phase. Therefore, the heat due to the liquefaction of the fuel vapor is absorbed by the melting of the heat storage material 48, and the heat is taken away, so that the temperature rise is suppressed. The temperature of the heat storage material 48 does not change during the phase change from the solid phase to the liquid phase. Further, the heat storage material 48 has a large heat of fusion and can take a large amount of heat. Therefore, in the main chamber 6, the temperature near the melting point is maintained, the temperature rise is suppressed, and the adsorption to the adsorbent 42 is promoted. Furthermore, even if the heat storage material 48 melts, the heat storage material 48 does not flow out because it is covered with the coating 46.

  When the fuel vapor is introduced into the main chamber 6, it is adsorbed by the adsorbent 42 on the inflow port 16 side, and the fuel vapor is sequentially adsorbed toward the adsorbent 42 on the lid member 2 side. The fuel vapor that has not been adsorbed by the adsorbent 42 in the main chamber 6 passes through the communication path 10 and is introduced into the sub chamber 8. Then, it is adsorbed by the adsorbent 50 in the sub chamber 8. At that time, in the case where the sub chamber 8 is filled with the heat storage material or the capsule 44, the heat due to the liquefaction of the fuel vapor is absorbed by the heat absorption of the heat storage material or the melting of the heat storage material 48, and the temperature rise is suppressed. The Therefore, adsorption to the adsorbent 50 is promoted.

  On the other hand, during operation of the internal combustion engine 20, air in the atmosphere is introduced from the introduction port 26 into the sub chamber 8 through the filter 34. The air introduced into the sub chamber 8 is guided to the main chamber 6 through the communication path 10 after the fuel is desorbed from the adsorbent 50 in the sub chamber 8. The adsorbent 50 in the sub chamber 8 has a large surface area, and the fuel adsorbed on the surface is quickly desorbed. Further, even the fuel adsorbed inside the adsorbent 50 is desorbed without remaining because the distance from the surface of the adsorbent 50 to the activated carbon inside is short, so that the fuel adsorbed from the adsorbent 50 in the sub chamber 8 is removed. , The fuel is quickly desorbed and the fuel vapor can be adsorbed quickly.

  The air containing fuel vapor is discharged to the intake pipe 22 through the main chamber 6, the outflow port 18, and the purge valve 24, and is burned in the internal combustion engine 20. When the desorption in the sub chamber 8 proceeds, the fuel is desorbed from the adsorbent 42 in the main chamber 6 in the same manner, the heat of vaporization is removed, and the temperature decreases. When the temperature becomes the freezing point of the heat storage material 48, in the heat storage material 48, the heat storage material 48 changes phase from a liquid phase to a solid phase, and solidification heat is released. In the main chamber 6, the temperature in the vicinity of the freezing point is maintained, temperature drop is suppressed, and fuel desorption from the adsorbent 42 is promoted.

  In this way, heat absorption / radiation is performed using the latent heat associated with the phase change of the heat storage material 48, so that the amount of heat is large, and the temperature change of the adsorbent 42 can be suppressed with a small amount of heat storage material 48. Therefore, the canister can be downsized, and the temperature change of the adsorbent 42 can be sufficiently suppressed even if the canister is downsized.

  Further, since the adsorbent 42 in the main chamber 6 is formed in a substantially columnar shape, desorption does not proceed near the center of the adsorbent 42 and fuel may remain, but the adsorbent 42 in the main chamber 6 It is formed in a substantially cylindrical shape so that more fuel can be adsorbed. On the other hand, the adsorbent 50 in the sub chamber 8 is formed with a short distance from the surface of the adsorbent 50 to the internal activated carbon, so that the desorption performance is improved rather than adsorbing more fuel. I am doing so. Thereby, when air is introduced from the introduction port 26, the fuel is quickly desorbed from the adsorbent 50 in the sub chamber 8, and the adsorption of the sub chamber 8 is quickly recovered.

  For example, even when the operation and stop of the internal combustion engine 20 are frequently repeated, the adsorption of the sub chamber 8 is quickly recovered, and the fuel vapor that is not operating is not adsorbed in the main chamber 6. However, it reliably adsorbs in the sub chamber 8 and prevents the fuel vapor from being discharged into the atmosphere. Therefore, the collection performance can be improved.

  In the case where the heat storage material or the capsule 44 is filled in the sub chamber 8, when the fuel is desorbed from the adsorbent 50, the heat of vaporization is deprived and the temperature decreases. The heat dissipation due to solidification suppresses the temperature drop. Therefore, desorption from the adsorbent 50 in the sub chamber 8 is promoted.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

It is sectional drawing of the canister as one Embodiment of this invention. It is an expanded sectional view of the capsule of this embodiment. It is an expansion perspective view of the adsorbent of this embodiment. It is explanatory drawing which shows the connection of the canister of this embodiment, a fuel tank, and an internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Lid member 4 ... Partition 6 ... Main chamber 8 ... Sub chamber 10 ... Communication path 12 ... Fuel tank 16 ... Inflow port 18 ... Outlet port 20 ... Internal combustion engine 22 ... Intake pipe 26 ... Inlet port 28,30, 32, 34, 36 ... Filter 38, 40 ... Perforated plate 42, 50 ... Adsorbent 44 ... Capsule 46 ... Coating 48 ... Heat storage material

Claims (5)

A container filled with an adsorbent is provided, and the inside of the container is divided into a main chamber and a sub chamber, and communicates with each other. An outflow port for discharging to the intake pipe of the engine, and an introduction port for introducing air into the sub chamber, and adsorbing fuel vapor introduced from the inflow port to the adsorbent, and from the introduction port In the canister for desorbing the fuel adsorbed on the adsorbent by the introduced air,
The main chamber is filled with a capsule containing a heat storage material that absorbs and dissipates heat by phase change together with the adsorbent, and the adsorbent filled in the sub chamber is formed from powdered activated carbon. And the said adsorbent was formed in the shape which shortened the distance from the surface of the said adsorbent to the said activated carbon inside, The canister characterized by the above-mentioned. 2. The canister according to claim 1, wherein the heat storage material absorbs and releases heat by a phase change between a solid phase and a liquid phase. The canister according to claim 1, wherein the capsule encloses the heat storage material with a heat-resistant resin. The canister according to any one of claims 1 to 3, wherein the sub chamber is further filled with a heat storage material having a large heat capacity. The canister according to any one of claims 1 to 3, wherein the sub chamber is further filled with a capsule containing a heat storage material that absorbs and dissipates heat by phase change.

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