Method for manufacturing a canister and an adsorbent

Abstract

The purpose of the present invention is to provide an adsorbent and a canister capable of improving adsorption and purging performance. The adsorbent (10) is filled into a canister and includes a cylindrical outer wall (10A) and a plurality of ribs (10B) that divide the outer wall (10A) into a plurality of cells along the axis of the outer wall (10A), wherein the thickness (dα) of the outer wall (10A) and the thickness (dβ) of the ribs (10B) are less than 0.6 mm, and the thickness of at least one of the outer wall (10A) and the ribs (10B) exceeds 0.4 mm. The outer diameter (D) of the outer wall (10A) is 3.5 mm to 40 mm, the BWC exceeds 3.0 g / dL, and the purging efficiency ((butane adsorption amount - butane retention amount) / butane adsorption amount) is 0.86 or greater.

Description

Technical Field

[0001] The present invention relates to an adsorbent used in a canister for evaporative fuel treatment that prevents evaporative fuel generated from a fuel tank from being released into the atmosphere, a canister, and a method for manufacturing the adsorbent.

Background Art

[0002] Conventionally, there has been a canister for evaporative fuel treatment that adsorbs and captures evaporative fuel generated by the evaporation of gasoline fuel stored in a fuel tank during vehicle stoppage or the like with an adsorbent made of activated carbon or the like, preventing the evaporative fuel from being released into the atmosphere.

[0003] Adsorbents such as activated carbon have the property that the lower the temperature, the higher the adsorption capacity, and the higher the temperature, the lower the adsorption capacity. Therefore, it is desirable that the temperature of the adsorbent is low during adsorption of evaporative fuel and high during purge. On the other hand, when evaporative fuel is adsorbed by the adsorbent, it releases heat corresponding to the heat of condensation, and when it desorbs (is purged) from the adsorbent, it takes away heat corresponding to the heat of evaporation. That is, the adsorption of evaporative fuel by the adsorbent is an exothermic reaction, and the desorption from the adsorbent is an endothermic reaction. Then, the heat generation and heat absorption due to the adsorption and desorption of evaporative fuel act in the opposite direction to the desirable temperature state of the adsorbent, that is, in the direction of inhibiting the adsorption and desorption performance of the adsorbent. Therefore, in order to improve the performance of the canister, it is desired to suppress the temperature change of the adsorbent due to the heat generation and heat absorption accompanying the adsorption and desorption of evaporative fuel.

[0004] Patent Document 1 discloses a hollow cylindrical adsorbent having an outer diameter of 4 to 6 mm. This adsorbent is formed with an outer cylindrical wall and cross-shaped radial walls extending from the center of the cylindrical wall. The thickness of each of the cylindrical wall and radial walls is 0.6 to 3 mm. Patent Document 2 discloses a hollow cylindrical adsorbent similar to Patent Document 1, having an outer cylindrical wall and cross-shaped radial walls extending from the center of the cylindrical wall. The thickness of each of the adsorbent is 0.6 to 1.5 mm. The adsorbents disclosed in Patent Documents 1 and 2 are hollow, so they have lower pressure loss than solid pellets and better purging performance. Furthermore, the thickness of each of the cylindrical wall and radial walls of the adsorbents disclosed in Patent Documents 1 and 2 is small, at 0.6 to 3 mm or 0.6 to 1.5 mm, but the cross-shaped radial walls are installed across the internal space of the hollow cylinder, thereby preventing a decrease in the hardness of the adsorbent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5867800 [Patent Document 2] Patent No. 6203043 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the adsorbents of Patent Documents 1 and 2, the adsorbent is formed into a hollow cylindrical shape, and the interior is divided into a cross shape by radial walls, thereby reducing pressure loss and improving purging performance. However, there is a demand for an adsorbent with even better purging performance.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to provide an adsorbent, a canister, and a method for manufacturing an adsorbent that can improve purging performance. [Means for solving the problem]

[0008] [Configuration] The characteristic configuration of the adsorbent according to the present invention is an adsorbent filled in a canister, comprising a cylindrical outer wall, and a plurality of ribs partitioning the plurality of cells along the axis of the outer wall, wherein the thickness of the outer wall and the thickness of the plurality of ribs are less than 0.6 mm, and at least one of the thicknesses of the outer wall and the plurality of ribs exceeds 0.4 mm, the outer diameter of the outer wall is 3.5 mm or more and 40 mm or less, the BWC in the BWC evaluation method according to ASTM D5228 exceeds 3.0 g / dL, and the purge efficiency represented by the following formula in the BWC evaluation method according to ASTM D5228 is 0.86 or more. Purge efficiency = (butane adsorption amount - butane retention amount) / butane adsorption amount ··· (1)

[0009] According to the above characteristic configuration, in the adsorbent, the internal space formed by the outer wall is divided into cells, which are a plurality of small spaces extending along the axis of the cylindrical outer wall, by the plurality of ribs. The purge air can pass through the cells along the axis, but since the thicknesses of the outer wall and the plurality of ribs constituting the adsorbent are relatively thin, less than 0.6 mm, the purge air easily passes through the outer wall and the ribs in the thickness direction. That is, the purge air easily flows through the small spaces formed by the cells, and the purge air easily passes through the inside of the outer wall and the ribs, so that the purge performance can be enhanced. Similarly, since the evaporated fuel passes through the cells along the axis and easily passes through the outer wall and the ribs in the thickness direction, it can be said that butane and the like in the evaporated fuel are captured at the molecular level in the outer wall and the ribs to enhance the adsorption performance. Along with this, the DBL (Diurnal Breathing Loss) performance is also improved. Note that when the thicknesses of the outer wall and the ribs are 0.6 mm or more, the adsorption performance and the purge performance decrease.

[0010] In order to enhance at least one of the adsorption performance and the purge performance in this way, the thicknesses of the outer wall and the plurality of ribs are made thinner. In this case, since the internal space formed by the outer wall with the plurality of ribs is divided into a plurality of cells, external pressure, internal pressure, etc. applied to the adsorbent are dispersed by the plurality of ribs. Therefore, the hardness of the adsorbent can be relatively increased, and breakage of the adsorbent can be suppressed. Furthermore, since the thickness of at least one of the outer wall and the ribs exceeds 0.4 mm, the thickness is not excessively thin, and the hardness of the adsorbent can be ensured. Note that when the thicknesses of both the outer wall and the ribs are 0.4 mm or less, the hardness of the adsorbent decreases.

[0011] Note that the adsorbent including the outer wall and the plurality of ribs with the above-described characteristic configuration is configured such that the BWC (Butane Working Capacity) exceeds 3.0 g / dL, the effective adsorption amount of butane is relatively large, and the adsorption performance is high. In this case, miniaturization and weight reduction of the adsorbent can be achieved. Also, since the purge efficiency, which is the ratio of the butane desorption amount after adsorbing butane and then desorbing butane, of the above-described adsorbent is 0.86 or more, the amount of butane remaining in the adsorbent can be reduced, and the DBL performance can be enhanced. Note that if the BWC becomes too large, the purge performance and the DBL performance decrease. Therefore, it is preferable that the BWC be 13.0 g / dL or less. To suppress the decrease in the purge performance and the DBL performance, more preferably, the BWC is 11.0 g / dL or less.

[0012] [Configuration] A further characteristic configuration of the adsorbent according to the present invention lies in that the outer diameter of the outer wall is 3.5 mm or more and 10 mm or less.

[0013] According to the above characteristic configuration, in the adsorbent with the outer diameter of the outer wall being 3.5 mm or more and 10 mm or less, the thicknesses of the outer wall and the plurality of ribs are made relatively thin, less than 0.6 mm. Thereby, the purge air can easily flow through the cells and also pass through the inside of the outer wall and the ribs. Therefore, even in a small adsorbent with the outer diameter of the outer wall being 3.5 mm or more and 10 mm or less, the purge performance and the DBL performance can be improved. Similarly, it can be said that the adsorption performance can be improved because the evaporated fuel can easily flow through the cells and also pass through the inside of the outer wall and the ribs.

[0014] [Configuration] A further characteristic configuration of the adsorbent according to the present invention is the thickness of the outer wall and the thicknesses of the plurality of ribs are less than 0.45 mm, and the outer diameter of the outer wall is more than 10 mm and 40 mm or less.

[0015] According to the above characteristic configuration, by configuring the adsorbent with the outer diameter of the outer wall being more than 10 mm and 40 mm or less, the thicknesses of the outer wall and the plurality of ribs can be made smaller, less than 0.45 mm, compared to the case where the outer diameter of the outer wall is 10 mm or less. Thereby, the purge performance and the DBL performance can be improved. Also, it can be said that the adsorption performance can be improved because the thicknesses of the outer wall and the plurality of ribs are thin as described above.

[0016] As described above, when the outer diameter of the adsorbent is made relatively large, more than 10 mm and 40 mm or less, the internal space formed by the outer wall becomes large, and for example, cells of 200 cells / inch or more can be formed in the axial direction view in this internal space. Therefore, the number of ribs increases corresponding to the number of cells, and external pressure, internal pressure, etc. applied to the adsorbent can be dispersed by the ribs, so the hardness of the adsorbent can be ensured even when the thicknesses of the outer wall and the plurality of ribs are less than 0.45 mm. 2

[0017] [Configuration] A characteristic configuration of the adsorbent according to the present invention is an adsorbent filled in a canister, a cylindrical outer wall, ​a plurality of ribs that divide the outer wall into a plurality of cells along an axis of the outer wall; The thickness of the outer wall and the thickness of the plurality of ribs are less than 0.6 mm; The outer diameter of the outer wall is 3.5 mm or more and 40 mm or less, The adsorbent contains 10% by mass or more and 70% by mass or less of a metal oxide relative to the adsorbent, The BWC in the BWC evaluation method according to ASTM D5228 is over 3.0 g / dL. The purge efficiency, as shown in the following formula, in the BWC evaluation method according to ASTM D5228 is 0.86 or higher. Purge efficiency = (butane adsorption amount - butane retention amount) / butane adsorption amount (1)

[0018] According to the above-described characteristic configuration, the adsorbent has an internal space formed by the outer wall, which is divided by multiple ribs into multiple small cells extending along the axis of the cylindrical outer wall. While purge air can pass through the cells along the axis, the relatively thin outer wall and multiple ribs (less than 0.6 mm) of the adsorbent facilitate its passage through the outer wall and ribs in the thickness direction. This facilitates the flow of purge air through the small spaces formed by the cells, and also facilitates its passage through the outer wall and ribs in the thickness direction, thereby improving purging performance. Similarly, since evaporated fuel passes through the cells along the axis and also easily passes through the outer wall and ribs in the thickness direction, the outer wall and ribs can capture butane and other compounds in the evaporated fuel at the molecular level, thereby improving adsorption performance. This also improves diurnal breathing loss (DBL) performance. Note that if the outer wall and ribs are thicker than 0.6 mm, adsorption and purging performance are reduced.

[0019] In order to enhance at least one of the adsorption performance and the purge performance in this way, the thicknesses of the outer wall and the plurality of ribs are made thinner. In this case, since the internal space formed by the outer wall with the plurality of ribs is divided into a plurality of cells, external pressure, internal pressure, etc. applied to the adsorbent are dispersed by the plurality of ribs. Therefore, the hardness of the adsorbent can be relatively increased, and breakage of the adsorbent can be suppressed. Furthermore, since the thicknesses of both the outer wall and the ribs exceed 0.4 mm, the thickness is not excessively thin, and the hardness of the adsorbent can be ensured. Note that when the thickness of at least one of the outer wall and the ribs is 0.4 mm or less, the hardness of the adsorbent decreases. Also, since a metal oxide, which is an inorganic substance with relatively high hardness, is contained in the adsorbent in an amount of 10% by mass or more and 70% by mass or less, in addition to heat control during adsorption and desorption due to the high heat capacity per volume of the metal oxide, the hardness of the adsorbent can be further increased.

[0020] Note that the adsorbent having the outer wall and the plurality of ribs with the above-described characteristic configuration is configured such that the BWC (Butane Working Capacity) exceeds 3.0 g / dL, the effective adsorption amount of butane is relatively large, and the adsorption performance is high. In this case, miniaturization and weight reduction of the adsorbent can be achieved. Also, since the purge efficiency, which is the ratio of the butane desorption amount after adsorbing butane and then desorbing butane, of the above-described adsorbent is 0.86 or more, the amount of butane remaining in the adsorbent can be reduced, and the DBL performance can be enhanced. Note that if the BWC becomes too large, the purge performance and the DBL performance decrease. Therefore, it is preferable that the BWC be 13.0 g / dL or less. To suppress a decrease in the purge performance and the DBL performance, more preferably, the BWC is 11.0 g / dL or less.

[0021] [Configuration] A further characteristic configuration of the adsorbent according to the present invention lies in that each of the shapes of the plurality of cells is at least one of a triangular shape and a hexagonal shape when viewed in the axial direction.

[0022] According to the above characteristic configuration, when each cell is at least one of a triangular shape and a hexagonal shape, the ribs are positioned corresponding to each side of the triangular shape and the hexagonal shape. Therefore, in the internal space formed by the outer wall, at least some of the ribs are arranged radially relative to the center of the internal space. This allows the external pressure, internal pressure, etc. applied to the adsorbent to be distributed approximately evenly throughout the adsorbent, thereby increasing the hardness of the adsorbent.

[0023] [composition] A further characteristic feature of the adsorbent according to the present invention is that the difference in equilibrium adsorption amount of n-butane concentration between n-butane concentrations of 5 vol% and 50 vol% exceeds 35 g / L.

[0024] According to the above-described characteristic configuration, the effective adsorption amount of molecules such as butane in the evaporated fuel is large, so that the adsorption performance of the adsorbent can be improved, which allows the adsorbent to be made smaller and lighter.

[0025] [composition] A further characteristic feature of the adsorbent according to the present invention is that the adsorbent is composed of at least activated carbon and a temperature control material having at least one of a volumetric specific heat and a thermal conductivity higher than those of the activated carbon.

[0026] According to the above-described characteristic configuration, the adsorbent includes, as one aspect, a temperature control material having a higher volumetric specific heat, i.e., a higher heat capacity, than activated carbon. Also, as one aspect, the adsorbent includes, as one aspect, a temperature control material having a higher thermal conductivity than activated carbon. Therefore, the heat generated by the activated carbon during adsorption of evaporated fuel is transferred to the temperature control material, suppressing the temperature rise of the activated carbon and improving the adsorption performance of the adsorbent. On the other hand, during purging of adsorbed fuel, the activated carbon removes the heat retained in the temperature control material, suppressing the temperature drop of the activated carbon and improving the purging performance of the adsorbent.

[0027] [composition] A further characteristic configuration of the adsorbent according to the present invention is that the temperature control material is at least one of a metal oxide, a phase change material having a phase change temperature of 36°C or lower, and a phase transition material having a phase transition temperature of 36°C or lower.

[0028] Metal oxides generally have a larger volume specific heat and thermal conductivity and a larger heat capacity than activated carbon. In the above characteristic configuration, when the temperature control material is a metal oxide, the temperature rise and fall of the adsorbent are suppressed, and the adsorption performance and purge performance can be improved. Also, at least one of the phase change material having a phase change temperature of 36°C or lower and the phase transition material having a phase transition temperature of 36°C or lower has a higher heat capacity than activated carbon. In the above characteristic configuration, when the temperature control material is at least one of the phase change material and the phase transition material, the heat generated by the activated carbon during the adsorption of the evaporated fuel is transferred to the temperature control material, so the temperature rise of the activated carbon is suppressed, and the adsorption performance of the adsorbent is improved. On the other hand, during the purge of the adsorbed fuel, the rate of temperature drop of the activated carbon is suppressed by the action of the metal oxide having a high heat capacity and the substances having a phase change function and a phase transition function, and the purge performance of the adsorbent is improved.

[0029] [Configuration] A further characteristic configuration of the adsorbent according to the present invention is that the adsorbent is at least composed of activated carbon. In the adsorbent, a first pore having a diameter of less than 100 nm derived from the activated carbon and a second pore having a diameter of 100 nm or more derived from the meltable core are formed, and the volume of the second pore exceeds 0.05 mL / g and is 0.35 mL / g or less with respect to the mass of the adsorbent.

[0030] According to the above characteristic configuration, since the pore volume of the second pore having a pore diameter of 100 nm or more exceeds 0.05 mL / g and is 0.35 mL / g or less with respect to the mass of the adsorbent, a passage through which the evaporated fuel and the purge air flow is appropriately formed in the adsorbent, the flow of the evaporated fuel and the purge air through the second pore is improved, and the adsorption performance and the purge performance are improved. If the pore volume of the second pores is 0.05 mL / g or less relative to the mass of the adsorbent, the proportion of passages within the adsorbent is small, the desorption rate is slow, and the adsorption and purging performance is reduced.If the pore volume of the second pores is more than 0.35 mL / g relative to the mass of the adsorbent, excessive passages through which evaporated fuel and purge air flow are formed within the adsorbent, reducing its strength.In addition, the activated carbon content is reduced, resulting in a lower BWC value.

[0031] [composition] A further characteristic feature of the adsorbent according to the present invention is that the number of cells is 200 cells / inch. 2 The above is true, and the number of the plurality of ribs is four or more.

[0032] According to the above characteristic configuration, the number of cells is 200 cells / inch 2 As described above, since the number of ribs is four or more, the external pressure, internal pressure, etc. applied to the adsorbent are dispersed by the large number of ribs, and the hardness of the adsorbent is improved.

[0033] [composition] The canister according to the present invention has the following characteristic configuration: A canister for treating evaporated fuel has a tank port communicating with an upper air chamber of a fuel tank of an internal combustion engine, a purge port communicating with an intake passage of the internal combustion engine, an atmosphere port open to the atmosphere, and an adsorbent chamber through which evaporated fuel flows from the tank port to the atmosphere port, The adsorbent is disposed in an atmosphere-side adjacent region of the adsorbent chamber adjacent to the atmosphere port.

[0034] Desorption (purging) of evaporated fuel from the activated carbon contained in the adsorbent is achieved by intake air from the purge port and atmospheric air flowing in from the atmospheric port. When evaporated fuel desorbs from the activated carbon, heat is removed, causing the temperature of the activated carbon to drop, thereby reducing the purging performance of the activated carbon. For example, if the temperature of the activated carbon drops below 10°C, the purging performance will drop significantly. According to the above characteristic configuration, the adsorbent is disposed in the atmosphere-side adjacent region of the adsorbent chamber adjacent to the atmospheric port. The thickness of the outer wall and the multiple ribs of the adsorbent is relatively thin, less than 0.6 mm, so that the purging air flows through the cells and passes through the outer wall and the ribs, resulting in excellent purging and DBL performance. Therefore, by disposing the adsorbent in the atmosphere-side adjacent region, the purging process is performed appropriately.

[0035] [composition] A further characteristic configuration of the canister according to the present invention is the adsorbent is disposed in an atmosphere-side separated region that is more distant from the atmosphere port than the atmosphere-side adjacent region and adjacent to the atmosphere-side adjacent region, The adsorbent disposed in the atmosphere-side adjacent region is a honeycomb adsorbent having an outer wall with an outer diameter of more than 10 mm and not more than 40 mm, The adsorbent disposed in the atmosphere-side isolation region is a honeycomb pellet having an outer wall with an outer diameter of 3.5 mm or more and 10 mm or less.

[0036] According to the above-described characteristic configuration, even if the BWC of the activated carbon disposed in the region separated from the atmosphere port is higher than that of the atmosphere-side separation region and the butane adsorption performance is high, the DBL performance of the canister can be enhanced by the honeycomb pellets and the honeycomb adsorbent disposed in each of the atmosphere-side separation region and the atmosphere-side adjacent region. That is, even when the amount of butane adsorbed is increased by the activated carbon disposed in the region separated from the atmosphere port as compared with the atmosphere-side separation region, since relatively small honeycomb pellets are disposed in the atmosphere-side separation region, the purge performance in the atmosphere-side separation region can be enhanced due to the large outer surface area of the honeycomb pellets, etc., and the DBL performance of the canister can be enhanced. Further, since a relatively large honeycomb adsorbent is further disposed in the atmosphere-side adjacent region adjacent to the atmosphere-side separation region, the BWC of the adsorbent (honeycomb adsorbent) in the atmosphere-side adjacent region is low, the remaining amount of butane after purge is small, and the DBL performance is improved.

[0037] [Configuration] A further characteristic configuration of the canister according to the present invention is that it satisfies the relationship of BWC of the honeycomb pellets > BWC of the honeycomb adsorbent.

[0038] According to the above-described characteristic configuration, the honeycomb pellets and the honeycomb adsorbent are disposed in the atmosphere-side separation region and the atmosphere-side adjacent region in this order toward the atmosphere port. And it satisfies the relationship of BWC of the honeycomb pellets > BWC of the honeycomb adsorbent, and the BWC becomes smaller toward the atmosphere port. Therefore, since the remaining amount of butane after purge can be reduced toward the atmosphere port, the purge performance of the canister can be enhanced and the DBL performance can be enhanced.

[0039] [Configuration] A further characteristic configuration of the canister according to the present invention is An adsorbent containing activated carbon having a BWC of 15.0 g / dL or more in the BWC evaluation method according to ASTM D5228 and at least one temperature control material selected from the group consisting of a phase change substance having a phase change temperature of 36°C or more and a phase change substance having a phase change temperature of 36°C or more is disposed in an adjacent tank side region of the adsorbent chamber adjacent to the tank port.

[0040] According to the above-described characteristic configuration, an adsorbent containing a temperature control material such as a phase change substance that absorbs and releases latent heat in response to temperature changes is disposed in the tank-side adjacent region of the adsorbent chamber, thereby suppressing temperature changes of the activated carbon and preventing performance degradation of the activated carbon.

[0041] Furthermore, when refueling a fuel tank, a large amount of evaporated fuel may flow into the canister at once. The evaporated fuel flowing in from the tank port forms an adsorption zone from the vicinity of the tank port toward the atmospheric port, where the heat of adsorption causes the temperature of the activated carbon to rise. When the temperature of the activated carbon exceeds 35°C (approximately 35°C), the adsorption performance of the activated carbon significantly decreases. According to the above characteristic configuration, the tank-side adjacent region is a region where the temperature of the activated carbon reaches 35°C or higher due to the heat generated by adsorption of evaporated fuel onto the activated carbon during refueling of the fuel tank. The tank-side adjacent region is provided with an adsorbent containing at least one temperature control material selected from the group consisting of a phase change substance having a phase change temperature of 36°C or higher and a phase change substance having a phase change temperature of 36°C or higher. This is preferable because it prevents the temperature of the activated carbon from exceeding 35°C. Furthermore, since the adsorbent containing activated carbon is disposed in the tank-side adjacent region, the amount of activated carbon stored in the adsorbent chamber is prevented from decreasing, and the adsorption performance is prevented from decreasing.

[0042] [composition] The characteristic configuration of the method for producing an adsorbent according to the present invention is as follows: The method for producing the adsorbent described above, At least activated carbon, an organic binder, a crosslinking agent, and an inorganic material are mixed and then kneaded; The kneaded material is molded into the molded body, The molded body is subjected to a drying treatment at 100°C or higher and 200°C or lower.

[0043] According to the above characteristic configuration, it can be said that an adsorbent with improved purge performance and DBL performance can be manufactured, and similarly, an adsorbent with improved adsorption performance can be manufactured. Further, since the adsorbent contains activated carbon, butane and the like in the evaporated fuel can be captured at the molecular level to enhance the adsorption performance. Furthermore, by subjecting the molded body added with the organic binder and the crosslinking agent to a drying treatment, the organic binder is crosslinked, and the resistance to the evaporated fuel can be improved. Also, since the inorganic material is contained, the BWC is improved, and the breakage of the molded body during the drying treatment is suppressed.

[0044] [Configuration] The characteristic configuration of the method for manufacturing an adsorbent according to the present invention is the above method for manufacturing an adsorbent, at least, activated carbon, an organic binder, and an inorganic material are mixed, and then kneaded, the kneaded kneaded material is molded into the molded body, the molded body is subjected to a firing treatment at 700°C or higher and 900°C or lower.

[0045] According to the above characteristic configuration, it can be said that an adsorbent with improved purge performance and DBL performance can be manufactured, and similarly, an adsorbent with improved adsorption performance can be manufactured. Further, since the adsorbent contains activated carbon, butane and the like in the evaporated fuel can be captured at the molecular level to enhance the adsorption performance. Furthermore, by allowing the evaporated fuel and the purge air to flow through the pores after the organic binder has disappeared by the firing treatment, the adsorption performance and the purge performance can be improved. Also, since the inorganic material is contained, the BWC is improved, and the breakage of the molded body during the firing treatment is suppressed.

[0046] [Configuration] A further characteristic configuration of the method for manufacturing an adsorbent according to the present invention is Furthermore, at least one of a metal oxide, a phase change substance having a phase change temperature of 36°C or less, and a phase change substance having a phase change temperature of 36°C or less is mixed as a temperature control material having at least one of a volumetric specific heat and a thermal conductivity higher than those of the activated carbon, and then kneaded.

[0047] According to the above-described characteristic configuration, by adding at least one of a metal oxide, a phase change material, and a phase transition material, which generally have a larger volumetric specific heat and thermal conductivity than activated carbon, to the adsorbent as a temperature control material, it is possible to suppress temperature increases and decreases in the adsorbent, thereby improving the adsorption performance and purging performance.

[0048] [composition] A further characteristic feature of the method for producing an adsorbent according to the present invention is that a meltable core is further mixed and then kneaded.

[0049] According to the above-mentioned characteristic configuration, by molding a kneaded material containing a meltable core and then drying or firing the molded material, the meltable core sublimes or decomposes to form pores. These pores serve as passages for the evaporated fuel and purge air, thereby improving adsorption and purging performance.

[0050] [composition] A further characteristic feature of the method for producing an adsorbent according to the present invention is that 10% by mass or more and 70% by mass or less of a metal oxide is further mixed with the adsorbent, and then the mixture is kneaded.

[0051] The adsorbent contains 10% by mass or more and 70% by mass or less of metal oxide, which is an inorganic substance with a relatively high hardness. This not only enables heat control during adsorption and desorption due to the high heat capacity per volume of the metal oxide, but also further increases the hardness of the adsorbent. [Brief explanation of the drawings]

[0052]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0053] 〔First Embodiment〕 Hereinafter, a canister according to the first embodiment and an adsorbent used in the canister will be described. In this embodiment, the canister is used for treating evaporated fuel generated from a fuel tank of an automobile. The adsorbent is filled in this canister. The evaporated fuel generated by the fuel tank heating up during engine operation or when the vehicle is stopped is adsorbed by the adsorbent filled in the canister, thereby preventing the evaporated fuel from being released into the atmosphere. The evaporated fuel adsorbed by the adsorbent is desorbed (purged) by the intake pipe negative pressure during engine operation or a suction pump that is driven and controlled independently of engine operation, and the adsorbent is regenerated.

[0054] (1) External Configuration of Adsorbent Hereinafter, first, the external configuration of the adsorbent will be described with reference to FIG. 1. As shown in FIG. 1, the adsorbent 10 of the present embodiment has a cylindrical outer wall 10A and a plurality of ribs 10B that partition the inside of the outer wall 10A into a plurality of cells 10C along the axis of the outer wall 10A. That is, the adsorbent 10 is configured as a hollow molded body and is formed by the cylindrical outer wall 10A and the ribs 10B that form a wall partitioning the internal space inside the cylindrical outer wall 10A. And the rib 10B partitions the internal space formed by the outer wall 10A into a honeycomb shape in the axial direction view, and forms a plurality of cells 10C. Here, the honeycomb shape includes not only the case where the cell 10C is hexagonal in the axial direction view, but also various shapes such as triangular, square, and pentagonal shapes. In FIG. 1, each cell 10C has a triangular shape in the axial direction view. Particularly, when the cell 10C is equilateral triangular in the axial direction view, a regular hexagonal shape can be formed by combining six cells 10C, and a plurality of cells 10C can be efficiently formed in the internal space to secure the number of cells, which is preferable.

[0055] The outer wall 10A and the ribs 10B extend in the longitudinal direction (the height direction in the side view). Thereby, a plurality of cells 10C partitioned in a honeycomb shape are formed to extend in the longitudinal direction. When the adsorbent 10 has such a honeycomb shape, purge air easily flows through the hollow region of the cell 10C, and the purge performance can be improved by increasing the contact time and contact area between the activated carbon and the purge air. Similarly, the evaporated fuel in the cell 10C flows well, and the adsorption performance can be improved by increasing the contact time and contact area between the activated carbon constituting the adsorbent 10 and the evaporated fuel. That is, according to the adsorbent 10 of the present embodiment, the purge performance can be enhanced. It can also be said that both the purge performance and the adsorption performance can be enhanced.

[0056] The outer diameter (diameter) D of the adsorbent 10 is, for example, 3.5 mm or more and 40 mm or less, and the length L in the longitudinal direction is, for example, 200 mm or less. In this embodiment, the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are formed to be less than 0.6 mm and are thin. Further, at least one of the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B exceeds 0.4 mm. Note that the adsorbent 10 with a relatively large outer diameter D and length L is sometimes simply referred to as a honeycomb adsorbent, and the adsorbent 10 with a relatively small size is sometimes referred to as a honeycomb pellet. For example, the adsorbent 10 with an outer diameter D of 3.5 mm or more and 10 mm or less may be referred to as a honeycomb pellet, and the adsorbent 10 with an outer diameter exceeding 10 mm and 40 mm or less may be referred to as a honeycomb adsorbent.

[0057] In the adsorbent 10 having the above outer diameter D, by making the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B thin as described above, in the internal space surrounded by the outer wall 10A, for example, 200 cells / inch 2 or more of the cells 10C can be formed in the axial direction view. Therefore, the number of ribs increases corresponding to the number of cells, and external pressure, internal pressure, etc. applied to the adsorbent 10 can be dispersed by the ribs 10B, and the hardness of the adsorbent 10 can be ensured.

[0058] This adsorbent 10 further has a BWC (Butane Working Capacity) exceeding 3.0 g / dL. Note that BWC is an evaluation value of butane adsorption performance measured by the BWC evaluation method according to ASTM D5228. Further, the adsorbent 10 has a purge efficiency represented by the following formula in the BWC evaluation method according to ASTM D5228 of 0.86 or more. Purge efficiency = (butane adsorption amount - butane retention amount) / butane adsorption amount ··· (1)

[0059] According to the adsorbent 10 described above, in the adsorbent 10, the internal space formed by the outer wall 10A is divided into cells 10C which are a plurality of small spaces by a plurality of ribs 10B. The purge air can pass through the inside of the cell 10C along the direction in which the cell 10C extends. However, since the thicknesses of the outer wall 10A and the plurality of ribs 10B constituting the adsorbent 10 are relatively thin, less than 0.6 mm, it is easier for the purge air to pass through the outer wall 10A and the ribs 10B in the thickness direction as well. That is, the purge air passes along the direction in which the cell 10C extends, and it is also easy for the purge air to pass through the outer wall 10A and the ribs 10B in the thickness direction, so that the purge performance can be enhanced. Along with this, the DBL (Diurnal Breathing Loss) performance is also improved. Similarly, the evaporated fuel can easily flow through the small spaces formed by the cells 10C, and since the evaporated fuel easily passes through the outer wall 10A and the ribs 10B, butane or the like in the evaporated fuel can be captured at the molecular level in the outer wall 10A and the ribs 10B to enhance the adsorption performance. That is, according to the adsorbent 10 in which the thicknesses of the outer wall 10A and the ribs 10B are relatively thin as in the present embodiment, it can be said that the purge performance can be enhanced and both the purge performance and the adsorption performance can be enhanced. In addition, when the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are 0.6 mm or more, the adsorption performance and the purge performance deteriorate.

[0060] In this way, in order to enhance at least one of the purge performance and the adsorption performance, the thickness dα of the outer wall 10A and the thickness dβ of the plurality of ribs 10B are made thin. However, since the internal space formed by the outer wall 10A is divided into a plurality of cells 10C by the plurality of ribs 10B, external pressure, internal pressure, etc. applied to the adsorbent 10 are dispersed by the plurality of ribs 10B. Therefore, the hardness of the adsorbent 10 can be relatively increased, and breakage or the like of the adsorbent 10 can be suppressed. Further, since at least one of the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B exceeds 0.4 mm, the thickness is not excessively thin, and the hardness of the adsorbent 10 can be ensured. In addition, when both the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are 0.4 mm or less, the hardness of the adsorbent 10 decreases.

[0061] Also, as shown in FIG. 1 above, in the adsorbent 10, the cells 10C are formed in a triangular shape. Therefore, at least a part of the plurality of ribs 10B extends radially with respect to the center of the internal space formed by the outer wall 10A, so that the external pressure, internal pressure, etc. applied to each cell 10C are dispersed throughout the adsorbent 10 by these radial ribs 10B. Therefore, the hardness of the adsorbent 10 can be ensured while reducing the thickness dα of the outer wall 10A and the thickness dβ of the plurality of ribs 10B. In particular, when the cell 10C is an equilateral triangle, a regular hexagon can be formed by combining six cells 10C, and the external pressure, internal pressure, etc. applied to each cell 10C can be more evenly dispersed radially, so that the hardness of the adsorbent 10 can be more ensured, which is preferable.

[0062] In addition, the above-mentioned adsorbent 10 is configured such that the BWC exceeds 3.0 g / dL, has a relatively large effective adsorption amount of butane, and high adsorption performance. In this case, miniaturization and weight reduction of the adsorbent 10 can be achieved. Also, since the purge efficiency, which is the ratio of the butane desorption amount after the adsorbent 10 adsorbs butane and then desorbs butane, is 0.86 or more, the amount of butane remaining in the adsorbent 10 can be reduced and the DBL performance can be enhanced.

[0063] Also, in the adsorbent 10 of FIG. 1 above, each cell 10C is triangular, but the shape of the cell 10C is not limited to this. For example, as shown in the adsorbent 10 of FIG. 2, each cell 10C may be hexagonal. Furthermore, for example, as shown in the adsorbent 10 of FIG. 3, each cell 10C may be square.

[0064] In the adsorbent 10 shown in FIGS. 2 and 3, the same reference numerals as those in FIG. 1 denote the same components. In the adsorbent 10 of FIG. 2, in the axial direction view, the internal space of the outer wall 10A is divided into a plurality of hexagonal cells 10C, and the ribs 10B form the hexagonal outer shape of the cells 10C. Therefore, at least a part of the plurality of ribs 10B extends radially with respect to the center of the internal space formed by the outer wall 10A, so that the external pressure, internal pressure, etc. applied to each cell 10C are dispersed throughout the adsorbent 10 by these radial ribs 10B. As a result, the hardness of the adsorbent 10 can be ensured while reducing the thickness dα of the outer wall 10A and the thickness dβ of the plurality of ribs 10B. Further, when a plurality of hexagonal cells 10C are formed in the internal space of the outer wall 10A, the hardness of the adsorbent 10 can be ensured even if the number of cells is smaller than when triangular cells 10C are formed.

[0065] Also, in the adsorbent 10 of FIG. 3, in the axial direction view, the internal space of the outer wall 10A is divided into a plurality of square cells 10C, and the ribs 10B form the square outer shape of the cells 10C. Since the plurality of ribs 10B extend in a matrix shape, the external pressure, internal pressure, etc. applied to each cell 10C are dispersed, and the thickness dα of the outer wall 10A and the thickness dβ of the plurality of ribs 10B can be reduced while ensuring the hardness of the adsorbent 10.

[0066] As described above, since the thicknesses of the outer wall 10A and the plurality of ribs 10B of the adsorbent 10 are relatively thin, less than 0.6 mm, purge air flows through the inside of the cell 10C and also passes through the outer wall 10A and the ribs 10B in the thickness direction, so that the purge performance for butane and the like adsorbed in the first pores (described later) formed in the outer wall 10A and the ribs 10B is high. Similarly, not only does the evaporated fuel flow through the inside of the cell 10C, but it also easily passes through the outer wall 10A and the ribs 10B in the thickness direction, and butane and the like in the evaporated fuel are easily captured in the first pores in the activated carbon, and it is also possible to enhance the adsorption performance of the adsorbent 10.

[0067] (2) Constituent Materials and Manufacturing Method of the Adsorbent The adsorbent 10 is formed from a raw material containing at least activated carbon having pores (first pores described later), an organic binder, a crosslinking agent, and an inorganic material. The manufacturing method of the adsorbent 10 is as follows. The raw materials including the aforementioned activated carbon, organic binder, crosslinking agent, and inorganic material are mixed and kneaded with water using a mixer such as a ribbon mixer. Then, the kneaded material is formed into the honeycomb shape shown in FIGS. 1 to 3 by extrusion molding or die molding. Thereafter, the formed material is dried at about 200°C or lower, for example, about 120°C for about 3 hours using infrared rays, hot air, steam, microwaves, etc., and the adsorbent 10 is manufactured. Drying at a relatively low temperature of about 200°C or lower, for example, about 120°C, can be, for example, a step of removing moisture from the molded body during molding, a step of crosslinking the organic binder with a crosslinking agent, a step of solidifying the inorganic material, etc.

[0068] As the activated carbon, those obtained from various raw materials such as commercially available coal-based, coconut shell-based, wood-based, lignin-based, etc. can be used. Furthermore, activated products of activated carbon such as steam-activated products, carbon dioxide-activated products, chemical-activated products using phosphoric acid, zinc chloride, alkali metals, etc. can also be used. Also, the activated carbon is formed into a porous structure and has first pores with a pore diameter of less than 100 nm. The first pores are preferably 50 nm or less, more preferably 40 nm or less. Even more preferably, for example, 1 to 10 nm, more preferably 2 to 5 nm.

[0069] And the activated carbon is preferably in a particulate or powdered form to increase the adsorption ability of the evaporative fuel. The average particle diameter of the activated carbon is preferably about 1 μm to 10 mm, for example, and powdered activated carbon with a particle diameter of 350 μm or less (42 mesh pass) can be used by crushing the activated carbon. Also, the specific surface area is usually 500 to 2500 m 2 / g, preferably 800 to 2300 m 2 / g. Note that the specific surface area of the selected activated carbon can be appropriately selected according to the BWC value of the adsorbent and the blending amount of the activated carbon.

[0070] Here, the pore diameter means the average pore diameter, and is measured, for example, by measuring adsorption and desorption isotherms using a nitrogen adsorption and desorption method, mercury intrusion porosimetry, etc. In this embodiment, the mercury intrusion porosimetry is used for measurement. Alternatively, the pore diameter can be determined by particle size analysis using an SEM.

[0071] In this embodiment, in which a drying step is performed in the production of adsorbent 10, the organic binder may be, for example, cellulose such as carboxymethyl cellulose (CMC), methyl cellulose, hydroxypropyl methyl cellulose, or hydroxyethyl methyl cellulose, or an emulsion binder such as EVA (ethylene vinyl acetate), epoxy, latex, styrene, or butadiene. The amount of such an organic binder added is approximately 3 to 15 mass % of the total mass of the raw materials used to produce adsorbent 10.

[0072] The crosslinking agent is preferably one that crosslinks the organic binder to improve gasoline resistance, water resistance, etc. Examples of crosslinking agents that can be used include ordinary crosslinking agents such as polyvalent metal ions, urea, polyamine, methylolmelamine, polyamide, epoxy, isocyanate, and oxazoline group-containing polymers. Instead of adding a cross-linking agent, a self-cross-linking binder can be used as the organic binder.

[0073] Examples of inorganic materials that can be used include powdered bentonite, kibushi clay, silica sol, alumina sol, and white clay, as well as solid sols. Adding inorganic materials can improve the BWC and hardness of adsorbent 10. Adding inorganic materials can also reduce breakage during drying of the molded body. The amount of inorganic material added is approximately 10 to 50% by mass of the inorganic material relative to the total mass of the raw materials used to manufacture adsorbent 10, including activated carbon, organic binder, crosslinker, and inorganic material.

[0074] (3) Additives to the adsorbent The above adsorbent 10 is formed from raw materials including at least activated carbon, an organic binder, a crosslinking agent, and an inorganic material, but it is also possible to further add the following additive materials. (a) Carbonized products To the raw materials of the adsorbent 10, carbonized products obtained by steaming and baking raw materials such as coconut shells and wood powder can be added as additive materials. By adding carbonized products, the BWC can be adjusted, and the hardness of the adsorbent 10 can be increased. Also, the carbonized products are added to the raw materials at a ratio of, for example, 5% by mass or more and 30% by mass or less.

[0075] (b) Metal oxides To the raw materials of the adsorbent 10, metal oxides can be added as additive materials. The metal oxides are, for example, oxides of aluminum, iron, etc. By adding metal oxides, in addition to heat control during adsorption and desorption due to the high heat capacity per volume of the metal oxides, the hardness of the adsorbent 10 can be increased. Also, the metal oxides are added to the raw materials at a ratio of, for example, 10% by mass or more and 70% by mass or less.

[0076] (c) Temperature control material To the raw materials of the adsorbent 10, a temperature control material for controlling the temperature of the adsorbent 10 can be added as an additive material.

[0077] As the temperature control material, a material having a higher heat capacity than activated carbon is preferably used. For example, as the temperature control material, a substance having a larger specific heat per volume than activated carbon is preferably used. Furthermore, as the temperature control material, a substance having a higher thermal conductivity than activated carbon is preferably used.

[0078] For example, metal oxides, which generally have higher volumetric specific heat and thermal conductivity than activated carbon, can be used. Examples of metal oxides include oxides of aluminum and iron. The volumetric specific heat of metal oxides is preferably 0.4 kcal / L·°C or more, and the thermal conductivity is preferably 0.5 kcal / m·h·°C or more. The specific heat of metal oxides is preferably 0.25 to 0.4 kcal / kg·°C or more. For example, the volumetric specific heat of activated carbon is 0.05 to 0.12 kcal / L·°C, and the thermal conductivity is 0.064 kcal / m·h·°C.

[0079] In addition to such activated carbon, adsorbent 10 containing a metal oxide having a higher heat capacity and thermal conductivity per volume than activated carbon preferably has a volumetric specific heat of 0.08 kcal / L·°C or more. Furthermore, adsorbent 10 containing the above metal oxide preferably has a thermal conductivity of 0.1 kcal / m·h·°C or more. The volumetric specific heat of adsorbent 10 is more preferably 0.12 kcal / L·°C or more, and even more preferably greater than 0.12 kcal / L·°C. Furthermore, adsorbent 10 preferably has a specific heat of, for example, 0.2 kcal / kg·°C or more.

[0080] Adding metal oxide to adsorbent 10 improves the ability of activated carbon to transfer heat generated during adsorption of evaporated fuel to the metal oxide, suppressing the temperature rise of the activated carbon and improving the adsorption performance of adsorbent 10. On the other hand, during purging of adsorbed fuel, the ability of activated carbon to remove the heat retained by the metal oxide is improved, suppressing the temperature drop of the activated carbon and improving the purging performance of adsorbent 10. In particular, by using a metal oxide as the temperature control material, which has a higher volumetric specific heat and thermal conductivity than activated carbon, as described above, it is possible to improve the adsorption performance and purging performance.

[0081] As mentioned above, the metal oxide in the adsorbent 10 also functions to increase the hardness of the adsorbent 10. Therefore, the proportion of metal oxide added to the raw materials should be determined taking into account its function as a temperature control material. Too little metal oxide not only reduces hardness but also reduces adsorption and purging performance. On the other hand, too much metal oxide reduces the activated carbon content, resulting in reduced adsorption performance. For example, since the adsorbent 10 has thin outer walls 10A and ribs 10B, the amount of metal oxide added to the adsorbent 10 can be determined with hardness as a priority. For example, adding 10% to 70% by mass of metal oxide to the adsorbent 10 can improve the hardness of the adsorbent 10. Furthermore, the presence of the metal oxide can suppress temperature increases and decreases, thereby improving adsorption and purging performance. As mentioned above, the relatively thin outer walls 10A and ribs 10B (less than 0.6 mm) can improve purging performance and adsorption performance.

[0082] The temperature control material is not limited to metal oxides as long as it has a volumetric specific heat and thermal conductivity greater than those of activated carbon, and may be inorganic oxides such as silicon.

[0083] Furthermore, instead of metal oxides, at least one of a phase change material and a phase transition material can be used as the temperature control material. The phase change material and the phase transition material have a higher heat capacity than activated carbon, and are preferably added so that the volumetric specific heat of the adsorbent 10 at the phase change temperature of the phase change material and the phase transition temperature of the phase transition material is 0.08 kcal / L°C or higher.

[0084] The phase change material and phase transition material are substances that change and transition phases at a predetermined phase change temperature and phase transition temperature, and have the same effect as the metal oxides. That is, the heat generated by the activated carbon during adsorption of evaporated fuel is transferred to the phase transition material, thereby suppressing a temperature rise in the activated carbon and improving the adsorption performance of the adsorbent 10. On the other hand, during purging of the adsorbed fuel, the activated carbon removes the heat retained by the phase transition material, thereby suppressing a temperature drop in the activated carbon and improving the purging performance of the adsorbent 10. In addition, combined with the relatively high latent heat of the phase change material and the phase transition material, the adsorption performance and purge performance of the adsorbent containing at least one of the phase change material and the phase transition material can be improved as described above.

[0085] The phase change temperature of the phase change material and the phase transition temperature of the phase transition material are preferably 36°C or lower. Further, the phase change material and the phase transition material are preferably in capsule form. The phase change material is not particularly limited as long as it can undergo a phase change between a solid phase and a liquid phase according to the temperature change of the activated carbon, and organic compounds or inorganic compounds can be used. Specifically, linear aliphatic hydrocarbons such as tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, heneicosane, docosane, hydrates of inorganic compounds such as natural wax, petroleum wax, LiNO3·3H2O, Na2SO4·10H2O, Na2HPO4·12H2O, fatty acids such as capric acid, lauric acid, palmitic acid, myristic acid, higher alcohols having 12 to 15 carbon atoms, and ester compounds such as methyl palmitate, methyl stearate, isopropyl palmitate, butyl stearate, stearyl stearate, myristyl myristate, etc. can be mentioned. Therefore, when using a phase change material, by adjusting the type and addition amount of the phase change material, the volume specific heat of the adsorbent 10 at the phase change temperature can be made, for example, 0.08 kcal / L·°C or higher.

[0086] In addition, examples of the phase transition material include an alloy of vanadium dioxide and tungsten (V X W Y O2) (X + Y = 1). For example, an alloy of vanadium dioxide and tungsten (V 0.98 W 0.02 O2) with X = 0.98 (98 parts by mass) and Y = 0.02 (2 parts by mass) can be mentioned. In this case, the phase transition temperature of the phase transition material (V 0.98 W 0.02 O2) is 20°C, and the volume specific heat of the adsorbent 10 at the phase transition temperature of the phase transition material can be made, for example, 0.08 kcal / L·°C or higher.

[0087] In the phase transition material comprising the aforementioned vanadium dioxide and tungsten alloy, the phase transition temperature can be adjusted to greater than 20°C by reducing Y (the tungsten content) below Y = 0.02 (2 parts by mass). Furthermore, by reducing Y (the tungsten content), the phase transition temperature can be adjusted to greater than 20°C but not greater than 36°C. Conversely, by increasing Y (the tungsten content) above Y = 0.02 (2 parts by mass), the phase transition temperature can be adjusted to less than 20°C. By adjusting Y (the tungsten content) in this manner, the volumetric specific heat of the adsorbent 10 at the phase transition temperature can be increased to, for example, 0.08 kcal / L·°C or higher. Furthermore, when a phase transition material is used, the volumetric specific heat of the adsorbent 10 at the phase transition temperature can be increased to, for example, 0.08 kcal / L·°C or higher by adjusting the type of phase transition material and the amount of phase transition material added to the adsorbent 10.

[0088] In the raw materials, the mass of at least one of the phase change substance and the phase transition substance is preferably 5% by mass or more and 30% by mass or less of the mass of the activated carbon. When fuel vapor desorbs from the activated carbon, heat is removed, causing a drop in the temperature of the activated carbon, which in turn reduces the purging performance of the activated carbon. For example, if the temperature of the activated carbon drops below 10°C, the purging performance drops significantly. The adsorbent 10 contains additives such as a phase-change substance and a phase-transition substance whose phase-change temperature is 36°C or less, thereby preventing an excessive drop in the temperature of the activated carbon contained in the adsorbent 10 and ensuring proper purging. Furthermore, by setting the addition ratio of the phase change substance and the phase transition substance to 5% by mass or more and 30% by mass or less of the mass of the activated carbon, the temperature of the activated carbon can be adjusted to an appropriate temperature. For example, if the addition ratio is less than 5% by mass, the effect of the phase change substance and the phase transition substance on preventing an excessive decrease in the temperature of the activated carbon is insufficient. On the other hand, if the addition ratio exceeds 30% by mass, the addition of the phase change substance and the phase transition substance reduces the proportion of activated carbon in the adsorbent, resulting in a decrease in adsorption performance.

[0089] (d) Meltable Core As a raw material of the adsorbent 10, a meltable core can be added as an additive material. As the meltable core, a material with a high melting point and easy to decompose is used, and it sublimates, or decomposes and volatilizes by drying at a predetermined temperature. When the raw material containing the meltable core is dried or the like, the meltable core sublimates, or decomposes and volatilizes, thereby forming the second pores. The second pores are formed to have a diameter and length similar to those of the meltable core. For example, the second pores are pores with a size of 1 μm or more. Such second pores serve as passages through which evaporation fuel and purge air flow, so that the adsorption performance and purge performance can be enhanced.

[0090] As the meltable core, polymers such as polyester, polypropylene, polymethyl methacrylate, pulp fiber, amide fiber, and cellulose fiber are used. More preferably, as the meltable core, polymethyl methacrylate, polyethylene, pulp fiber, etc. can be used.

[0091] In the adsorbent 10 of the present embodiment, purge air flows through the plurality of cells 10C, and the thin outer wall 10A and ribs 10B allow the purge air to permeate, so the purge performance is high. Similarly, evaporation fuel flows through the plurality of cells 10C, and the thin outer wall 10A and ribs 10B allow the evaporation fuel to permeate, so the adsorption performance can also be enhanced. Therefore, polyethylene, pulp fiber, etc. can be in powder form to form short second pores. That is, since the permeation of evaporation fuel and purge air can be improved without increasing the length of the second pores, the length of the second pores can be shortened to suppress the decrease in the hardness of the adsorbent 10.

[0092] The second pores have a pore diameter of 1 μm or more, preferably 1 μm or more and 100 μm or less. Since the pore diameter of the second pores is in such a range, a decrease in the hardness of the adsorbent can be suppressed. Note that when the pore diameter of the second pores exceeds 100 μm, the second pores in the adsorbent become too large to maintain the hardness, lacking practicality as an adsorbent. The pore diameter of the second pores is preferably 1 μm or more and 60 μm or less, more preferably 1 μm or more and 50 μm or less. When the diameter of the second pores is less than 1 μm, the flow of the evaporated fuel and the air during purging is poor, the desorption rate becomes slow, and the purge performance deteriorates. On the other hand, when the diameter of the second pores exceeds 100 μm, the volume of the second pores existing in the skeleton of the adsorbent 10 increases, and the hardness of the adsorbent 10 decreases.

[0093] When the meltable core is pulp fiber, the length is preferably 0.5 mm or less. Also, it is preferable that the meltable core has a C-N bond. When forming the adsorbent 10, when a meltable core having a C-N bond, activated carbon, an additive material, etc. are kneaded and heated, the C-N bond of the meltable core is broken by heating and easily decomposes and volatilizes. Thereby, the second pores derived from the fibrous meltable core having a C-N bond can be formed in the adsorbent 10. Further, due to the presence of the C-N bond, the blockage of the second pores due to the formation of carbides during heating can be suppressed.

[0094] When the adsorbent 10 is formed including the above meltable core, pores including first pores less than 100 nm possessed by the activated carbon and second pores of 1 μm or more derived from the meltable core are formed in the adsorbent 10. More specifically, as shown in FIG. 1, the molded body of the adsorbent 10 is formed from a skeleton composed of an outer wall 10A and ribs 10B, and has first pores less than 100 nm derived from activated carbon and second pores of 1 μm or more derived from the meltable core. Such an adsorbent 10 can capture, for example, butane in the evaporated fuel at the molecular level by the first pores less than 100 nm, and can enhance the adsorption performance. Further, the second pores of 1 μm or more serve as passages through which the evaporated fuel and the purge air flow, so that the adsorption performance and the purge performance can be enhanced.

[0095] (4) Further configuration of the adsorbent (a) Honeycomb pellet Among the adsorbents 10 of the above embodiment (the outer diameter D is, for example, larger than 3.5 mm and 40 mm or less, and the length L in the longitudinal direction is, for example, 200 mm or less), even in the relatively small honeycomb pellets where the outer diameter D of the adsorbent 10 is larger than 3.5 mm and 10 mm or less, the thicknesses of the outer wall 10A and the ribs 10B can be reduced. That is, the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are less than 0.6 mm, and at least one of the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B exceeds 0.4 mm. Thereby, even in relatively small honeycomb pellets, the purge performance and the DBL performance can be improved. Also, even in relatively small honeycomb pellets, it is possible to improve the adsorption performance.

[0096] (b) Honeycomb adsorbent Among the adsorbents 10 of the above embodiment, even in the honeycomb adsorbents where the outer diameter D of the adsorbent 10 is larger than 10 mm and 40 mm or less, the thicknesses of the outer wall 10A and the ribs 10B can be reduced. That is, the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are less than 0.6 mm, and at least one of the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B exceeds 0.4 mm. Thereby, even in relatively large honeycomb adsorbents, the purge performance and the DBL performance can be improved, and similarly, the adsorption performance can be improved. Further, when the outer diameter D of the honeycomb adsorbent is made relatively large, exceeding 10 mm and 40 mm or less, the internal space formed by the outer wall becomes large, and in this internal space, for example, 200 cells / inch 2 or more of the above cells 10C can be formed. Therefore, the number of ribs increases corresponding to the number of cells, and external pressure, internal pressure, etc. applied to the adsorbent 10 can be dispersed by the ribs 10B, so that the hardness of the adsorbent 10 can be ensured even when the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are less than 0.45 mm.

[0097] (c) Adsorbent containing metal oxide When the adsorbent 10 contains 10% by mass or more and 70% by mass or less of metal oxide, the thickness dα of the outer wall 10A and the thickness dβ of the ribs 10B can be less than 0.6 mm. The outer diameter D can be, for example, greater than 3.5 mm and 40 mm or less, and the longitudinal length L can be, for example, 200 mm or less, as in the adsorbent 10 of the above embodiment. The external and internal pressures applied to the adsorbent 10 are dispersed by the multiple ribs, increasing the hardness of the adsorbent 10. The inclusion of 10% by mass or more and 70% by mass or less of metal oxide in the adsorbent 10 further increases the hardness in addition to the thermal control during adsorption and desorption due to the high heat capacity per volume of the metal oxide. When the hardness of the adsorbent 10 can be increased, the thickness dα of the outer wall 10A and the thickness dβ of the ribs can be preferably less than 0.44 mm, more preferably 0.4 mm or less, and even more preferably 0.3 mm or less. Furthermore, the thickness can be set to 0.15 mm or more, more preferably 0.23 mm or more, taking into consideration a decrease in hardness of the adsorbent 10. Increasing the hardness of the adsorbent 10 in this way allows the thickness of the outer wall and the plurality of ribs to be reduced, further improving the purging performance and DBL performance, and similarly, making it possible to improve the adsorption performance.

[0098] (d) BWC In the above, the BWC is set to exceed 3.0 g / dL. If the BWC is too large, the purge performance and DBL performance will decrease, so the BWC is preferably set to 13.0 g / dL or less. In order to prevent the decrease in the purge performance and DBL performance, the BWC is more preferably set to 11.0 g / dL or less.

[0099] (e) Purge efficiency The purge efficiency of the adsorbent 10 is 0.86 or more, preferably 0.88 or more, and more preferably 0.9 or more. If the purge efficiency is less than 0.86, the DBL performance will be reduced.

[0100] (f) Number of cells and ribs In the adsorbent 10, by making the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B as thin as described above, for example, 200 cells / inch in the axial direction view in the internal space surrounded by the outer wall 10A 2 or more of the cells 10C can be formed. Preferably 200 cells / inch 2 or more of the cells 10C can be formed. Also preferably 300 cells / inch 2 or more of the cells 10C, more preferably 500 cells / inch 2 or more of the cells 10C, more preferably 600 cells / inch 2 or more of the cells 10C, even more preferably 700 cells / inch 2 or more of the cells 10C can be formed. By forming a plurality of cells 10C in this way, the number of ribs is at least 4 or more. As the number of cells increases, the number of ribs increases, and external pressure, internal pressure, etc. applied to the adsorbent 10 can be dispersed by the plurality of ribs 10B, ensuring the hardness of the adsorbent 10. Also, considering the ease of purge air flow in the cell 10C, the hardness of the outer wall 10A and the rib 10B, etc., the cell number is set to 800 cells / inch so that the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are suppressed within the above range 2 or less. Similarly, considering the ease of evaporation fuel flow, it can be said that it is preferable to set the cell number to 800 cells / inch 2 or less.

[0101] (g) Difference in equilibrium adsorption amount In the adsorbent 10 described above, it is preferable that the difference in the equilibrium adsorption amount of n-butane concentration exceeds 35 g / L between an n-butane concentration of 5 vol% and 50 vol%. In this case, since the effective adsorption amount of molecules such as butane in the evaporation fuel is large, the adsorption performance of the adsorbent 10 can be enhanced. Thereby, miniaturization and weight reduction of the adsorbent 10 can be achieved.

[0102] (h) Volume of the second pores When the adsorbent 10 described above is composed of a raw material containing a meltable core, a first pore with a diameter of less than 100 nm derived from activated carbon and a second pore with a diameter of 1 μm or more derived from the meltable core are formed. Here, it is preferable that the volume of the second pore exceeds 0.05 mL / g and is 0.35 mL / g or less with respect to the mass of the adsorbent 10. In this case, the evaporation fuel and the purge air can easily flow through the second pore, and the adsorption performance, purge performance, and DBL performance are improved, which is preferable. More preferably, the ratio of the volume of the second pore to the mass of the adsorbent 10 is 0.1 mL / g or more, and even more preferably 0.15 mL / g or more.

[0103] (i) Adsorption functional material In the above, activated carbon was included in the raw material of the adsorbent 10. However, as long as the adsorbent 10 can adsorb molecules such as butane in the evaporation fuel, the raw material of the adsorbent 10 may include activated carbon, activated alumina, silica gel, zeolite, organometallic complex, silica porous body, etc., or a mixture thereof. However, preferably, for example, activated carbon, activated alumina, or a mixture thereof can be used, and more preferably activated carbon can be used.

[0104] (4) Canister Next, the canister 100 using the above adsorbent 10 will be described with reference to FIG. 4. The canister 100 is installed for treating evaporation fuel generated from the fuel tank of an automobile. The canister 100 includes a case 21, a cover 22, a plate 28, a coil spring 29, and a filter F. An adsorbent chamber R is formed inside the canister 100, and the adsorbent 10 for the canister manufactured above is stored therein.

[0105] The case 21 is a member made of a hollow cylindrical synthetic resin (for example, nylon) with an open bottom. The cover 22 is a member made of a disk-shaped synthetic resin (for example, nylon). The cover 22 is joined to the lower side of the case 21 by, for example, vibration welding or adhesion, and closes the opening of the case 21.

[0106] On the upper side of the case 21, a tank port 23, a purge port 24, and an atmosphere port 25 are formed. The tank port 23 communicates with the upper part of a fuel tank (not shown) of an automobile, and evaporated fuel generated from the fuel tank flows into the inside of the case 21 through the tank port 23. The purge port 24 communicates with an intake passage (not shown) of an internal combustion engine. The intake passage communicates with an intake pipe of the internal combustion engine or is connected to a suction pump that is driven and controlled independently of the driving of the engine. The atmosphere port 25 is open to the atmosphere, and the atmosphere flows into the inside of the case 21 through the atmosphere port 25.

[0107] Inside the case 21, a partition wall 26 and an auxiliary partition wall 27 are formed. The partition wall 26 is a partition wall that extends from the upper end inside the case 21 to the vicinity of the cover 22 and is located between the purge port 24 and the atmosphere port 25. The auxiliary partition wall 27 is a short partition wall that extends from the upper end inside the case 21 toward the cover 22 and is located between the tank port 23 and the purge port 24.

[0108] By the partition wall 26, the space inside the case 21 is divided into left and right. And the space on the right side in the figure (the space on the atmosphere port 25 side) is partitioned vertically by the filter F. The lower space (the space on the cover 22 side) of this space on the atmosphere port 25 side is defined as the second region 32, and the upper space (the space on the atmosphere port 25 side) is defined as the third region 33. Also, the space on the tank port 23 side divided by the partition wall 26 is defined as the first region 31. In the present embodiment, the above-described adsorbent 10 for the canister is disposed in the third region 33, and activated carbon is disposed in the first region 31 and the second region 32.

[0109] The filter F, disposed between the first region 31 and the second region 32, is a filter made of synthetic resin nonwoven fabric or urethane foam, and is configured to allow the passage of evaporated fuel and air. A plate 28 is disposed below the first region 31 and the second region 32. The plate 28 is a metal plate with a large number of through-holes formed therein, and is configured to allow the passage of evaporated fuel and air. The plate 28 is biased upward by a coil spring 29, thereby compressing the canister adsorbent 10 and activated carbon sealed in the first region 31, the second region 32, and the third region 33 upward.

[0110] With the above configuration, a U-shaped flow path is formed inside the canister 100, extending between the tank port 23 (and the purge port 24) and the atmospheric port 25. The evaporated fuel flowing in from the tank port 23 first flows into the first region 31, passes under the plate 28, flows into the second region 32, and then flows into the third region 33. The first region 31, the second region 32, and the third region 33 are regions that adsorb the evaporated fuel flowing from the tank port 23 to the atmospheric port 25, and contain activated carbon and the canister adsorbent 10. hereinafter, these regions may be collectively referred to as the adsorbent chamber R. The first region 31 is adjacent to the tank port 23 and may be referred to as the tank-side adjacent region T. The third region 33 is adjacent to the atmospheric port 25 and may be referred to as the atmospheric-side adjacent region U.

[0111] As described above, in this embodiment, the canister adsorbent 10 is disposed in the atmosphere-side adjacent region U, which is the third region 33. Desorption (purging) of evaporated fuel from the activated carbon (adsorbent) contained in the canister adsorbent 10 is performed by intake air from the purge port 24 and atmospheric air flowing in from the atmospheric port 25. The canister adsorbent 10 has excellent purging performance because the outer wall 10A and the ribs 10B are formed to be relatively thin. Therefore, by disposing the canister adsorbent 10 in the atmosphere-side adjacent region U within the canister 100, the purging performance of the canister can be improved.

[0112] In addition, when the adsorbent for the canister contains at least one of a metal oxide, a phase transition substance, and an additive material for the phase transition substance, it is preferable because it can suppress the temperature rise and fall of the adsorbent such as activated carbon. That is, when the evaporated fuel desorbs from the adsorbent such as activated carbon, heat is taken away, so the temperature of the adsorbent drops and the purge performance deteriorates. For example, when the temperature of the activated carbon, which is the adsorbent, drops below 10°C, the purge performance deteriorates significantly. According to the above configuration, since the above-described adsorbent 10 for the canister is disposed in the atmosphere-side adjacent region U adjacent to the atmosphere port 25 in the adsorbent chamber R, an excessive drop in the temperature of the activated carbon contained in the adsorbent 10 for the canister in the atmosphere-side adjacent region U is suppressed, and the purge process is appropriately performed.

[0113] In the present embodiment, the above-described adsorbent 10 for the canister is disposed in the atmosphere-side adjacent region U, but the above-described adsorbent 10 for the canister can also be disposed in the tank-side adjacent region T.

[0114] 〔Second Embodiment〕 Next, the canister according to the second embodiment and the adsorbent used in the canister will be described. The adsorbent 10 according to the second embodiment is different in the composition of the raw materials and the manufacturing method, etc. from the adsorbent 10 according to the first embodiment. The differences will be mainly described, and the external configuration of the other adsorbents and the application to the canister, etc. are the same as those in the first embodiment, so the description will be omitted.

[0115] The adsorbent 10 according to the second embodiment is formed from a raw material containing at least activated carbon having first pores, an organic binder, and an inorganic material. That is, in the adsorbent 10 according to the first embodiment, a crosslinking agent was contained in the raw material, but in the adsorbent 10 according to the second embodiment, the crosslinking agent is not an essential material added to the raw material. Such a raw material is formed into the adsorbent 10 through a firing process. In the first embodiment, mainly the organic binder and the crosslinking agent function as the binder that constitutes the adsorbent 10 as a molded body, but in the second embodiment, mainly the inorganic material functions as the binder that constitutes the adsorbent 10 as a molded body.

[0116] The manufacturing method of the adsorbent 10 according to the second embodiment is as follows. The raw materials including the aforementioned activated carbon, organic binder, and inorganic material are mixed and kneaded with water using a mixer such as a ribbon mixer. Then, the kneaded material is formed into the honeycomb shape shown in FIGS. 1 to 3 by extrusion molding or die molding. Thereafter, the formed material is dried at about 200°C or lower, for example, at about 120°C for about 3 hours using infrared rays, hot air, steam, microwaves, etc. Next, the molded body is fired at 650°C to 1000°C, for example, at 800°C for about 3 hours in an inert gas atmosphere using a belt kiln or the like to produce the adsorbent 10. Drying at a relatively low temperature of about 200°C or lower, for example, about 120°C, and firing at a relatively high temperature of 650°C to 1000°C can be, for example, a process of removing the moisture of the molded body during molding, a process of solidifying the inorganic material, etc.

[0117] Also, as the organic binder, in this embodiment, since the firing process is carried out in the production of the adsorbent 10, an organic binder used when molding a normal honeycomb can be used. As the organic binder, for example, carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, etc. can be used. The addition amount of such an organic binder is about 3 to 15% by mass based on the total mass of the raw materials used to produce the adsorbent 10.

[0118] Also, as described above, the firing process is included in the formation process of the adsorbent 10 according to the second embodiment. When the raw material of the adsorbent 10 according to the second embodiment contains a meltable core, drying at a relatively low temperature and firing at a relatively high temperature can be a sublimation process of a sublimable substance such as the meltable core.

[0119] In addition, regarding the adsorbent 10 according to the second embodiment, it is the same as the adsorbent 10 of the first embodiment in that carbonized products, metal oxides, temperature control materials, fusible cores, etc. may be included in the raw materials. Further, regarding the additional configurations applicable to the adsorbent 10 described in the first embodiment, they are also applicable to the adsorbent 10 according to the second embodiment. Also, the adsorbent 10 according to the second embodiment is applicable to a canister in the same manner as the first embodiment.

[0120] [Examples and Comparative Examples of Adsorbents] Below, adsorbents according to examples and comparative examples were manufactured, and the results in Tables 1 to 3 were obtained. In the following examples and comparative examples, the amounts of each raw material are described in absolute amounts (g), but the amounts of each raw material are not limited to this, and it is also possible to replace them with relative amounts (parts by mass). (Example 1) A raw material containing 53 g of activated carbon with a BWC of 15, 6.5 g of CMC as an organic binder, 1 g of an oxazoline group-containing polymer as a crosslinking agent, 25 g of bentonite as an inorganic material, and 14.5 g of carbonized coconut shell was mixed and kneaded with water using a mixer. The kneaded material was molded by an extruder so that each cell 10C was triangular in the axial direction view, and an adsorbent was obtained by drying at 120°C for 3 hours. The adsorbent has an outer diameter of 6 mm, a wall thickness of the outer wall of 0.59 mm, a rib thickness of 0.27 mm, and 700 cells / inch in the axial direction view 2 and is as follows. (Example 2) An adsorbent was obtained in the same manner as in Example 1 using the same raw materials except that 14.5 g of bentonite as an inorganic material and 25 g of Fe2O3 as a metal oxide were added to the raw materials and no carbonized coconut shell was added. (Example 3) An adsorbent was obtained in the same manner as in Example 1 using the same raw materials except that 4.5 g of carbonized coconut shell and 10 g of 7-μm microcapsules having a melamine coating encapsulating hexadecane as a phase change material were added to the raw materials.

[0121] (Example 4) Instead of the phase change material, 10 g of a phase transition material (V 0.98 W 0.02 O2) was added to the raw materials, and an adsorbent was obtained in the same manner as in Example 3 using the same raw materials. (Example 5) To the raw materials, 20 g of polyethylene (PE) as a meltable core and 15.5 g of carbonized coconut shell were added, and the same raw materials as in Example 1 were used except that no cross-linking agent was added. The raw materials were mixed and kneaded with water using a mixer, and the kneaded material was molded by an extrusion molding machine so that each cell 10C was triangular in the axial direction view, and dried at 120 °C for 3 hours. Then, the adsorbent was obtained by firing the molded body at 800 °C for about 3 hours. (Example 6) To the raw materials, 25 g of Fe2O3 as a metal oxide was added, and an adsorbent was obtained in the same manner as in Example 5 using the same raw materials except that carbonized coconut shell was not added.

[0122] (Example 7) To the raw materials, 59 g of activated carbon with a BWC of 15 and 19 g of bentonite as an inorganic material were added, and the same raw materials as in Example 1 were used and mixed and kneaded with water using a mixer. The kneaded material was molded by an extrusion molding machine so that each cell 10C was hexagonal in the axial direction view, and an adsorbent was obtained by drying at 120 °C for 3 hours. The adsorbent has an outer diameter of 36 mm, an outer wall thickness of 0.42 mm, a rib thickness of 0.19 mm, and 600 cells / inch 2 of cells. (Example 8) To the raw materials, 53 g of activated carbon with a BWC of 15 and 25 g of bentonite as an inorganic material were added, and the same raw materials as in Example 7 were used. Also, the adsorbent was manufactured to have an outer diameter of 36 mm, an outer wall thickness of 0.5 mm, a rib thickness of 0.25 mm, and 300 cells / inch 2 and an adsorbent was obtained using the same method as in Example 7 except for this.

[0123] (Example 9) Raw materials containing 53 g of activated carbon with a BWC of 15, 6.5 g of CMC as an organic binder, 25 g of bentonite as an inorganic material, and 53 g of Fe2O3 as a metal oxide were mixed and kneaded with water using a mixer. The kneaded material was molded using an extruder so that each cell 10C had a square shape when viewed from the axial direction, and the adsorbent was obtained by drying at 120°C for 3 hours. The adsorbent has an outer diameter of 4 mm, an outer wall thickness of 0.3 mm, a rib thickness of 0.25 mm, and a cell count of 600 cells / inch. 2 It is.

[0124] Example 10 Raw materials containing 41 g of activated carbon with a BWC of 17, 6.5 g of CMC as an organic binder, 14 g of bentonite as an inorganic material, 21 g of Fe2O3 as a metal oxide, and 6.5 g of polyethylene (PE) as a meltable core were mixed and kneaded with water using a mixer. The kneaded material was molded using an extruder so that each cell 10C had a hexagonal shape when viewed from the axial direction, and the adsorbent was obtained by drying at 120°C for 3 hours. The adsorbent has an outer diameter of 36 mm, an outer wall thickness of 0.55 mm, a rib thickness of 0.42 mm, and a cell count of 300 cells / inch. 2 It is.

[0125] Example 11 An adsorbent was obtained using the same raw materials and method as in Example 10, except that 47 g of activated carbon having a BWC of 17 was used as the raw material. The adsorbent of Example 11 has the same outer diameter as Example 10, 36 mm, rib thickness of 0.42 mm, and cell number of 300 cells / inch, except that the thickness of the outer wall is 0.45 mm. 2 It is.

[0126] Example 12 An adsorbent was obtained using the same raw materials and method as in Example 10, except that 49 g of activated carbon having a BWC of 17 was used as the raw material. The adsorbent of Example 12 has the same outer diameter, outer wall thickness, rib thickness and number of cells as the adsorbent of Example 11.

[0127] (Example 13) An adsorbent was obtained in the same manner as in Example 12, using the same raw materials as in Example 12, except that 6.5 g of polymethyl methacrylate (PMMA) with an average particle diameter of 1.5 μm was used as the meltable core. The adsorbent of Example 13 has the same outer diameter, outer wall thickness, rib thickness, and number of cells as the adsorbent of Example 11. The average particle diameter refers to the particle diameter measured by the laser diffraction / scattering method.

[0128] (Comparative Example 1) A kneaded material using the same raw materials as in Example 1 was molded by an extrusion molding machine so that each cell 10C was square in the axial direction view, and dried at 120 °C for 3 hours to obtain an adsorbent. The adsorbent has an outer diameter of 6 mm, an outer wall thickness of 0.8 mm, a rib thickness of 0.44 mm, and 290 cells per inch 2 is. (Comparative Example 2) An adsorbent was obtained in the same manner as in Comparative Example 1, using the same raw materials as in Comparative Example 1, except that 56 g of activated carbon with a BWC of 11 and 11.5 g of carbonized coconut shell were added to the raw materials. (Comparative Example 3) To the raw materials, 50 g of activated carbon with a BWC of 13, 37 g of bentonite as an inorganic material, and 13 g of polyethylene (PE) as a meltable core were added, and the same raw materials as in Comparative Example 1 were used except that CMC as an organic binder, a crosslinking agent, and carbonized coconut shell were not added. Also, the adsorbent was manufactured to have an outer diameter of 4.9 mm, an outer wall thickness of 0.8 mm, a rib thickness of 0.7 mm, and 200 cells per inch 2 An adsorbent was obtained using the same method as in Comparative Example 1, except that it was manufactured to have the above dimensions.

[0129] (Comparative Example 4) To the raw materials, 75 g of activated carbon with a BWC of 11, 10 g of CMC as an organic binder, and 15 g of bentonite as an inorganic material were added, and the same raw materials as in Comparative Example 1 were used except that carbonized coconut shell was not added. Also, the adsorbent has an outer diameter of 4 mm, an outer wall thickness of 0.28 mm, a rib thickness of 0.29 mm, and 500 cells per inch2 An adsorbent was obtained in the same manner as in Comparative Example 1, except that it was manufactured so as to achieve [the specified condition]. (Comparative Example 5) The same raw materials as in Comparative Example 1 were used. Also, the adsorbent had an outer diameter of 6 mm, an outer wall thickness of 0.4 mm, a rib thickness of 0.3 mm, and 500 cells per inch. 2 An adsorbent was obtained in the same manner as in Comparative Example 1, except that it was manufactured so as to achieve [the specified condition].

[0130] For each adsorbent manufactured in the above Examples and Comparative Examples, the physical property values shown in Tables 1 to 3 were obtained. Among the physical property evaluations in Tables 1 to 3, "BWC", "Difference in equilibrium adsorption amount between butane concentrations of 5 vol% - 50 vol%", "Purge efficiency", "B.R", "Hardness", and "Volume of the second pores (pore diameter of 100 nm or more) / mass of the adsorbent" are the evaluation values for each of the adsorbents 10 in Examples 1 to 13 and Comparative Examples 1 to 5. On the other hand, for DBL, it is the evaluation value as a canister when each of the adsorbents 10 in Examples 1 to 13 and Comparative Examples 1 to 5 was disposed in the third region 33 of the canister in Figure 4.

Table 1

Table 2

Table 3

[0131] Measurements of various physical property values such as BWC, the difference in equilibrium adsorption amount between butane concentrations of 5 vol% - 50 vol%, and BR (Butane Retentivity) were carried out in accordance with ASTM D5228. The purge efficiency was determined from the following formula. Purge efficiency = (Butane adsorption amount - Butane retention amount) / Butane adsorption amount ··· (1) The cumulative pore volume (mL / g) was determined by dividing the total mercury intrusion volume (mL) when pressure was applied from 1.7 psia to 27,500 psia in the second pore analysis of the porous resin by the sample weight (g).

[0132] The hardness was measured by using a commercially available wooden hardness tester to measure the breaking strength. When the adsorbent is the above-mentioned honeycomb pellet, if its breaking strength is 15 N or more, it is rated AA (Excellent); if it is 10 N or more and less than 15 N, it is rated A (Good); if it is 5 N or more and less than 10 N, it is rated B (Below Average); if it is less than 5 N, it is rated C (Poor). On the other hand, when the adsorbent is the above-mentioned honeycomb adsorbent, if its breaking strength is 50 N or more, it is rated AA; if it is 30 N or more and less than 50 N, it is rated A; if it is 10 N or more and less than 30 N, it is rated B; if it is less than 10 N, it is rated C.

[0133] The DBL performance was evaluated as follows. According to the US Bleed Emission Test Method (BETP), it was judged by the purge amount at which the DBL emission amount of the canister is less than 20 mg. AA (Excellent) is the case where, after the butane addition step at 40 g / hr, a purge of 100 BV or less (a purge amount 100 times the volume of the canister) is given and the DBL emission amount over 2 days is less than 20 mg. A (Good) is the case where, after the butane addition step at 40 g / hr, a purge of 157 BV or less (a purge amount 157 times the volume of the canister) is given and the DBL emission amount over 2 days is less than 20 mg. B (Below Average) is the case where, after the butane addition step at 40 g / hr, a purge of 210 BV or less (a purge amount 210 times the volume of the canister) is given and the DBL emission amount over 2 days is less than 20 mg. C (Poor) is the case where, after the butane addition step at 40 g / hr, a purge of 210 BV or less (a purge amount 210 times the volume of the canister) is given and the DBL emission amount over 2 days is 20 mg or more.

[0134] (Outer diameter, thickness of the outer wall, and thickness of the rib) In Examples 1 to 6, the thickness dα of the outer wall 10A is 0.59 mm, in Example 7, the thickness dα of the outer wall 10A is 0.42 mm, and in Example 8, the thickness dα of the outer wall 10A is 0.5 mm. In Examples 1 to 8, the BWC is 6.4 to 7.1 g / dL, and the difference in the equilibrium adsorption amount between 5 vol% and 50 vol% of the butane concentration (hereinafter simply referred to as the difference in the equilibrium adsorption amount) is 36 to 40 g / L. Also, in Examples 1 to 8, the purge efficiency is 0.89 to 0.93. The hardness is particularly excellent as AA in Examples 1 to 4, and generally good as A in Examples 5 to 8. The DBL performance is generally good as A in Examples 1, 7, and 8, and particularly excellent as AA in Examples 2 to 6.

[0135] Also, in Example 10, the thickness dα of the outer wall 10A is 0.55 mm, and in Examples 11 to 13, the thickness dα of the outer wall 10A is 0.45 mm. In Examples 10 to 13, the BWC is 9.2 to 10 g / dL, and the difference in the equilibrium adsorption amount is 43 to 47 g / L. Also, in Examples 10 to 13, the purge efficiency is 0.9 to 0.92. In Examples 10 to 13, the hardness is generally good as A, and the DBL performance is particularly excellent as AA.

[0136] On the other hand, in Comparative Examples 1 to 3, the thickness dα of the outer wall 10A is 0.8 mm. In Comparative Examples 1 to 3, the BWC is 5.7 to 7.5 g / dL, and the difference in the equilibrium adsorption amount is 32 to 42 g / L. Also, in Comparative Examples 1 to 3, the purge efficiency is 0.78 to 0.82. The hardness is particularly excellent as AA in Comparative Example 3, and generally good as A in Comparative Examples 1 and 2. However, the DBL performance is C for all of Comparative Examples 1 to 3 and is low.

[0137] From the above results, in Examples 1 to 8 and 10 to 13, the thickness dα of the outer wall 10A is less than 0.6 mm, and it can be seen that the BWC, the difference in equilibrium adsorption amount, the purge efficiency, the hardness, the DBL performance, etc. are superior to those of Comparative Examples 1 to 3 where the thickness dα of the outer wall 10A is 0.6 mm or more. In particular, it can be seen that when the thickness dα of the outer wall 10A is 0.6 mm or more, the DBL performance deteriorates. Also, in Comparative Example 2, the difference in equilibrium adsorption amount is 32 g / L, which is lower than that of Examples 1 to 8 and 10 to 13. The purge efficiency of Comparative Examples 1 to 3 is lower than that of Examples 1 to 8 and 10 to 13. Therefore, in the adsorbent 10, by setting the thickness dα of the outer wall 10A to less than 0.6 mm, the purge efficiency and the like are excellent, and in particular, the DBL performance can be enhanced, which is preferable.

[0138] Also, in Comparative Example 4, the thickness dα of the outer wall 10A is 0.28 mm, and in Comparative Example 5, the thickness dα of the outer wall 10A is 0.4 mm. In Comparative Examples 4 and 5, the BWC is 7.1 and 6.3, the difference in equilibrium adsorption amount is 41 and 35 g / L, respectively. Also, the purge efficiency is 0.9 and 0.89. The hardness is particularly poor as C in Comparative Example 4 and slightly poor as B in Comparative Example 5. Also, the DBL performance is generally good as A in Comparative Example 4, but slightly poor as B in Comparative Example 5. On the other hand, in Example 7, the thickness dα of the outer wall 10A is 0.42 mm, the hardness is generally good as A, and the DBL performance is generally good as A. Also, in Example 10, the thickness dα of the outer wall 10A is 0.55 mm, and in Examples 11 to 13, the thickness dα of the outer wall 10A is 0.45 mm. In Examples 7, 10 to 13, the hardness is generally good as A, and the DBL performance is particularly excellent as AA. Therefore, in the adsorbent 10, when the thickness dα of the outer wall 10A exceeds 0.4 mm, it is preferable because the hardness and the DBL performance can be enhanced.

[0139] From the above, in the adsorbent 10, the thickness dα of the outer wall 10A is less than 0.6 mm. Also, it is preferable that the thickness dα exceeds 0.4 mm. In Example 7, when the thickness dα of the outer wall 10A is 0.42 mm, the hardness and DBL performance are generally good. In Example 7, since the adsorbent 10 has an outer diameter D of 36 mm, in the relatively large adsorbent 10, the thickness dα of the outer wall 10A can also be less than 0.45 mm. In this case, it is preferable that the thickness dα of the outer wall 10A exceeds 0.4 mm. Also, in Examples 11 to 13, when the thickness dα of the outer wall 10A is 0.45 mm, the hardness is generally good and the DBL performance is particularly excellent.

[0140] Regarding the thickness dβ of the rib 10B of the adsorbent 10, it can be defined in the same manner as the thickness dα of the outer wall 10A. That is, the thickness dβ of the rib 10B is at least less than 0.6 mm. Also, the thickness dβ may exceed 0.4 mm. Regarding the thickness dβ of the rib 10B, in the relatively small adsorbent 10 of Examples 1 to 6, it is 0.27 mm. Also, in the relatively large adsorbent 10, the thickness dβ of the rib 10B is 0.19 mm in Example 7 and 0.25 mm in Example 8. Also, in Examples 10 to 13 which are relatively large adsorbents 10, the thickness dβ of the rib 10B is 0.42 mm. In these cases, the hardness and DBL performance are generally good or particularly excellent.

[0141] In Examples 1 to 6, the outer diameter D is 6 mm, and it is a relatively small honeycomb pellet with an outer diameter D of 3.5 mm or more and 10 mm or less. Also, in Examples 7, 8, 10 to 13, the outer diameter D is 36 mm, and it is a relatively large honeycomb adsorbent with an outer diameter exceeding 10 mm and 40 mm or less. Also in the honeycomb pellet and in the honeycomb adsorbent, the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are less than 0.6 mm, and it is preferable that at least one of the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B exceeds 0.4 mm.

[0142] Furthermore, the thickness dβ of the rib 10B is considered. In Examples 1 to 6, the thickness dβ of the rib 10B is 0.27 mm, in Example 7, the thickness dβ of the rib 10B is 0.19 mm, in Example 8, the thickness dβ of the rib 10B is 0.25 mm, and in Examples 10 to 13, the thickness dβ of the rib 10B is 0.42 mm. On the other hand, in Comparative Examples 1 and 2, the thickness dβ of the rib 10B is 0.44 mm, and in Comparative Example 3, the thickness dβ of the rib 10B is 0.7 mm. As described above, the DBL performance of Comparative Examples 1 to 3 is inferior to that of Examples 1 to 8 and 10 to 13. Therefore, more preferably, the thickness dβ of the rib 10B is less than 0.44 mm, and even more preferably, it is 0.3 mm or less. Also, preferably, the thickness dβ of the rib 10B is 0.15 mm or more, and more preferably, it is 0.19 mm or more. Referring to Examples 1 to 8 and 10 to 13, the thickness dβ of the rib 10B can be appropriately adjusted to less than 0.6 mm depending on the shape of the cells constituting the adsorbent, the amount of cross-linking agent, inorganic material, carbonized product, metal oxide, etc. added.

[0143] Also, in Example 9, the outer diameter D is 4 mm, the thickness dα of the outer wall 10A is 0.3 mm, and the thickness dβ of the rib 10B is 0.25 mm. In Example 9, 53 g of Fe2O3 is contained as the metal oxide. The addition amount of the metal oxide is 38.5% by mass. Since the metal oxide is formed from relatively hard inorganic substances, the hardness of the adsorbent 10 increases due to the inclusion of the metal oxide in the adsorbent 10. Therefore, in Example 9, the hardness is generally good at A. Also, in Example 9, the DBL performance is particularly excellent at AA.

[0144] Also, in Example 2, the outer diameter D is 6 mm, the thickness dα of the outer wall 10A is 0.59 mm, the thickness dβ of the rib 10B is 0.27 mm, and 25 g of Fe2O3 is contained as the metal oxide. The addition amount of the metal oxide is 25% by mass. In Example 2, the hardness is particularly excellent at AA. Also, in Example 2, the DBL performance is particularly excellent at AA. In Example 6, the outer diameter D is 6 mm, the thickness dα of the outer wall 10A is 0.59 mm, the thickness dβ of the rib 10B is 0.27 mm, and 25 g of Fe2O3 is contained as the metal oxide. The addition amount of the metal oxide is 19.3 mass%. In Example 6, the hardness is particularly excellent at AA. Also, in Example 6, the DBL performance is generally good at A.

[0145] In Example 10, the outer diameter D is 36 mm, the thickness dα of the outer wall 10A is 0.55 mm, the thickness dβ of the rib 10B is 0.42 mm, and 21 g of Fe2O3 is contained as the metal oxide. The addition amount of the metal oxide is 23.6 mass%. In Example 10, the hardness is generally good at A, and the DBL performance is particularly excellent at AA. In Example 11, the outer diameter D is 36 mm, the thickness dα of the outer wall 10A is 0.45 mm, the thickness dβ of the rib 10B is 0.42 mm, and 21 g of Fe2O3 is contained as the metal oxide. The addition amount of the metal oxide is 22.1 mass%. In Example 11, the hardness is generally good at A, and the DBL performance is particularly excellent at AA.

[0146] In Examples 12 and 13, the outer diameter D is 36 mm, the thickness dα of the outer wall 10A is 0.45 mm, the thickness dβ of the rib 10B is 0.42 mm, and 21 g of Fe2O3 is contained as the metal oxide. As the meltable core, 6.5 g of polyethylene (PE) is contained in Example 12, and 6.5 g of polymethyl methacrylate (PMMA) is contained in Example 13. In Examples 12 and 13, the addition amount of the metal oxide is 21.6 mass%. In Examples 12 and 13, the hardness is generally good at A, and the DBL performance is particularly excellent at AA.

[0147] From this, for the adsorbent 10 containing 10% by mass or more and 70% by mass or less of the metal oxide with respect to the adsorbent 10, the thickness dα of the outer wall and the thickness dβ of the rib can be made less than 0.6 mm. In Example 9, the outer diameter D is 4 mm, and it is a relatively small honeycomb pellet with the outer diameter D being 3.5 mm or more and 10 mm or less. However, considering that by increasing the outer diameter D to some extent, the number of cells in the cells 10C formed in the internal space increases and the hardness increases, so the thickness dα of the outer wall 10A and the thickness dβ of the rib can be made thinner. The aforementioned content of the metal oxide, the thickness dα of the outer wall, and the thickness dβ of the rib are applicable to honeycomb pellets and honeycomb adsorbents with the outer diameter D being 3.5 mm or more and 40 mm or less.

[0148] Further, a comparison is made between the adsorbent 10 of Example 9 in which the square cells 10C are formed and the adsorbents 10 of Comparative Examples 1 and 2 in which the square cells 10C are formed. In Example 9, the thickness dα of the outer wall 10A is 0.3 mm, while in Comparative Examples 1 and 2, the thickness dα of the outer wall 10A is 0.8 mm. Also, in Example 9, the thickness dβ of the rib 10B is 0.25 mm, while in Comparative Examples 1 and 2, the thickness dβ of the rib 10B is 0.44 mm. Regarding the DBL performance, Comparative Examples 1 and 2 are particularly poor at C, while Example 9 is particularly excellent at AA. Therefore, in the adsorbent 10 containing 10% by mass or more and 70% by mass or less of the metal oxide with respect to the adsorbent 10, the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are preferably less than 0.44 mm, more preferably 0.4 mm or less, and still more preferably 0.3 mm or less.

[0149] Also, in the adsorbent 10 containing 10% by mass or more and 70% by mass or less of the metal oxide with respect to the adsorbent 10, considering the decrease in hardness, the thickness dα of the outer wall and the thickness dβ of the rib can be 0.15 mm or more, and more preferably 0.23 mm or more. For example, as shown in Example 9, the thickness dα of the outer wall is preferably 0.3 mm or more, and the thickness dβ of the rib is preferably 0.25 mm or more. When the cells 10C are quadrangular, as in the adsorbent of Example 9, the hardness tends to be lower than that of the adsorbents 10 having triangular and hexagonal cells 10C of Examples 1 to 8 and 10 to 13. However, as described above, the hardness of the adsorbent 10 can be increased by including 10% by mass or more and 70% by mass or less of a metal oxide in the adsorbent 10.

[0150] (BWC) In Examples 1 to 9, the BWC was 6.4 to 7.1 g / L, and in Examples 10 to 13, the BWC was 9.2 to 10 g / L. Therefore, it is preferable that the BWC be greater than 3.0 g / dL and not more than 13.0 g / dL. To improve adsorption performance, the BWC is more preferably 5.0 g / dL or more, and even more preferably 6.0 g / dL or more. To prevent a decrease in purge performance and DBL performance, the BWC is more preferably 11.0 g / dL or less.

[0151] (Purge efficiency) The purge efficiency was 0.89 to 0.94 in Examples 1 to 9 and 10 to 13. Therefore, the purge efficiency of the adsorbent 10 of the Examples is preferably 0.86 or more, more preferably 0.88 or more, and even more preferably 0.9 or more.

[0152] (Cell shape, number of cells and number of ribs) In Examples 1 to 6, the cells 10C have a triangular shape, and the number of cells is 700 cells / inch when viewed in the axial direction. 2 In Examples 1 to 4, the hardness was AA, which was particularly excellent, and in Examples 5 and 6, the hardness was A, which was generally good. In Example 1, the DBL performance was ◯, which was generally good, and in Examples 2 to 6, the DBL performance was AA, which was particularly excellent. In Example 7, the cell 10C has a hexagonal shape and the number of cells is 600 cells / inch. 2 The hardness is generally good with a rating of 0, and the DBL performance is generally good with a rating of 0. In Example 8, the cell 10C has a hexagonal shape and the number of cells is 300 cells / inch. 2 The hardness is generally good with a rating of 0, and the DBL performance is generally good with a rating of 0. In Example 9, the cell 10C has a rectangular shape and the number of cells is 600 cells / inch. 2 The hardness is generally good with a rating of 0, and the DBL performance is particularly excellent with a rating of AA. In Examples 10 to 13, the cells 10C were hexagonal and had a cell count of 300 cells / inch. 2 The hardness is generally good with a rating of 0, and the DBL performance is particularly excellent with a rating of AA.

[0153] On the other hand, in Comparative Examples 1 and 2, the cell 10C has a rectangular shape and the number of cells is 290 cells / inch 2 In Comparative Examples 1 and 2, the hardness is generally good with a grade of ◯, but the DBL performance is particularly poor with a grade of C. In Comparative Example 3, the cell 10C has a rectangular shape and the number of cells is 200 cells / inch. 2 The hardness is particularly excellent at AA, but the DBL performance is particularly poor at C. In Comparative Example 4, the cell 10C has a rectangular shape and the number of cells is 500 cells / inch. 2 The hardness is particularly poor at C, but the DBL performance is generally good at ◯. In Comparative Example 5, the cell 10C has a rectangular shape and the number of cells is 500 cells / inch. 2 The hardness is B, which is slightly poor, and the DBL performance is also B, which is slightly poor.

[0154] Therefore, the number of cells is 200 cells / inch 2 More preferably, it is 300 cells / inch or more. 2 More than 500 cells / inch, preferably 500 cells / inch 2 More than 600 cells / inch, preferably 600 cells / inch 2 More than 700 cells / inch, more preferably 700 cells / inch 2 That's all. The number of ribs is 200 cells / inch. 2 By making the number of ribs 10B equal to or greater than 4, the number of ribs becomes at least 4. Therefore, it is preferable to form the adsorbent 10 on which the ribs 10B are formed so that the number of ribs is 4 or more, depending on the number of cells.

[0155] Comparing Examples 1 to 13 with Comparative Examples 1 to 5, Examples 1 to 13 having triangular and hexagonal cells 10C have better properties than the adsorbents of Comparative Examples 1 to 5 having square cells 10C. In Example 9, although it has the same square cell 10C as Comparative Examples 1 to 5, the hardness is ○ and it is generally good, and the DBL performance is AA and particularly excellent. In Example 9, since the metal oxide is contained in the adsorbent 10 in an amount of 10% by mass or more and 70% by mass or less, the thickness dα of the outer wall 10A can be reduced to 0.3 mm, and the thickness dβ of the rib 10B can be reduced to 0.25 mm. It is considered that the purge performance and DBL performance are improved. Similarly, since the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B are small, it is considered that the adsorption performance can also be improved. Therefore, as the shape of the cell 10C, a triangular shape and a hexagonal shape are preferable. Also, when the hardness can be ensured and the thickness dα of the outer wall 10A and the thickness dβ of the rib 10B can be reduced, a square cell 10C can be adopted.

[0156] (Difference in equilibrium adsorption amount) In Examples 1 to 9, the difference in equilibrium adsorption amount is 36 to 40 g / L, and the adsorption performance is high. Therefore, it is preferable that the difference in equilibrium adsorption amount exceeds 35 g / L. In Examples 10 to 13, the difference in equilibrium adsorption amount is 43 to 47 g / L, and the adsorption performance is even higher. On the other hand, the adsorbents of Examples 10 to 13 are particularly excellent in DBL performance with AA. Therefore, the adsorbents of Examples 10 to 13 have particularly improved adsorption performance and purge performance.

[0157] (Volume of the second pores) In Example 5, the volume of the second pores is 0.34 mL / g with respect to the mass of the adsorbent 10, the difference in the equilibrium adsorption amount is 36 g / L, the hardness is ○ which is generally good, and the DBL performance is AA which is particularly excellent. In Example 6, the volume of the second pores is 0.31 mL / g with respect to the mass of the adsorbent 10, the difference in the equilibrium adsorption amount is 39 g / L, the hardness is ○ which is generally good, and the DBL performance is AA which is particularly excellent. In Examples 10 to 13, the volume of the second pores is 0.2 mL / g with respect to the mass of the adsorbent 10, the difference in the equilibrium adsorption amount is 43 to 47 g / L, the hardness is ○ which is generally good, and the DBL performance is AA which is particularly excellent. Therefore, it is preferable that the volume of the second pores exceeds 0.05 mL / g and is 0.35 mL / g or less with respect to the mass of the adsorbent 10. When the pore volume of the second pores is 0.05 mL / g or less with respect to the mass of the adsorbent 10, the ratio of the passages in the adsorbent 10 is small, the desorption rate becomes slow, and the adsorption performance and purge performance deteriorate. Further, when the pore volume of the second pores exceeds 0.35 mL / g with respect to the mass of the adsorbent 10, passages through which the evaporated fuel and purge air flow are excessively formed in the adsorbent 10, resulting in a decrease in strength, and also the content of the activated carbon decreases, so the value of BWC decreases.

[0158] (Addition ratio of metal oxide) In Example 2, 53 g of activated carbon, 6.5 g of carboxymethyl cellulose, 1 g of crosslinking agent, 14.5 g of inorganic material are included, and 25 g of metal oxide is added. In this case, the addition amount of the metal oxide is 25% by mass. In Example 6, 53 g of activated carbon, 6.5 g of carboxymethyl cellulose, 25 g of inorganic material, 20 g of meltable core are included, and 25 g of metal oxide is added. In this case, the addition amount of the metal oxide is 19.3% by mass. In Example 9, 53 g of activated carbon, 6.5 g of carboxymethyl cellulose, 25 g of inorganic material are included, and 53 g of metal oxide is added. In this case, the addition amount of the metal oxide is 38.5% by mass.

[0159] In Example 10, 41 g of activated carbon, 6.5 g of carboxymethyl cellulose, 14 g of inorganic material, 21 g of metal oxide, and 6.5 g of polyethylene (PE) as a meltable core were added. In this case, the amount of metal oxide added was 23.6 mass %. In Example 11, 47 g of activated carbon, 6.5 g of carboxymethyl cellulose, 14 g of inorganic material, 21 g of metal oxide, and 6.5 g of polyethylene (PE) as a meltable core were added, and the amount of metal oxide added was 22.1 mass %. In Example 12, 49 g of activated carbon, 6.5 g of carboxymethyl cellulose, 14 g of inorganic material, 21 g of metal oxide, and 6.5 g of polyethylene (PE) as a meltable core were added. In this case, the amount of metal oxide added was 21.6 mass %. In Example 13, 49 g of activated carbon, 6.5 g of carboxymethyl cellulose, 14 g of inorganic material, 21 g of metal oxide, and 6.5 g of polymethyl methacrylate (PMMA) as a meltable core were added. In this case, the amount of metal oxide added was 21.6 mass %. Based on the above results, the metal oxide is preferably contained in an amount of 10% by mass to 70% by mass, more preferably 15% by mass to 50% by mass, and even more preferably 19% by mass to 40% by mass, relative to the adsorbent 10. Because the metal oxide not only increases the hardness of the adsorbent 10 but also functions as a temperature control material, the proportion of the metal oxide added to the raw materials should be determined taking into account the balance between these two functions.

[0160] (Charcoal addition ratio) The addition ratio of the carbonized product to the raw material is 14.5% by mass in Examples 1, 7, and 8, 4.5% by mass in Example 3, 14.5% by mass in Example 4, and 12.9% by mass in Example 5. Therefore, the addition ratio of the carbonized product to the raw material is preferably, for example, 5% by mass or more and 30% by mass or less with respect to the raw material, and more preferably 10% by mass or more and 20% by mass or less. By adding the carbonized product, the BWC can be adjusted, and the hardness of the adsorbent 10 can be increased.

[0161] (Addition ratio of the phase change substance or phase transition substance) The addition ratio of the phase change substance to the activated carbon is 18.9% by mass in Example 3. The addition ratio of the phase transition substance to the raw material is 18.9% by mass in Example 4. Therefore, the addition ratio of the phase change substance or phase transition substance to the activated carbon is preferably 5% by mass or more and 30% by mass or less.

[0162] [Other Embodiments] Note that the configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction occurs. Further, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

[0163] (1) In the above embodiment, the adsorbent 10 for the canister is disposed in the atmosphere-side adjacent region U, but the adsorbent for the next canister can be disposed in the tank-side adjacent region T. The activated carbon used for the adsorbent for the canister of the modification is preferably such that the BWC is 15.0 g / dL or more in the BWC evaluation method according to ASTM D5228. And it includes activated carbon having a BWC of 15.0 g / dL or more in the BWC evaluation method according to ASTM D5228 and at least one of an additive material of a phase change substance having a phase change temperature of 36°C or more and a phase transition substance having a phase transition temperature of 36°C or more.

[0164] According to the above configuration, the canister adsorbent containing an additive material such as a phase-change substance that absorbs and releases latent heat in response to temperature changes is disposed in the tank-side adjacent region T of the adsorbent chamber R. Therefore, the canister adsorbent can suppress temperature changes in the activated carbon, preventing performance degradation of the activated carbon.

[0165] Furthermore, when refueling the fuel tank, a large amount of evaporated fuel may flow into the canister 100 at once. The evaporated fuel flowing in from the tank port 23 forms an adsorption zone from the vicinity of the tank port 23 toward the atmospheric port 25, and the heat of adsorption increases the temperature of the activated carbon in the adsorption zone. When the temperature of the activated carbon exceeds 35°C (approximately 35°C), the adsorption performance of the activated carbon significantly decreases. According to the above configuration, the tank-side adjacent region T is a region where the temperature of the activated carbon reaches 35°C or higher due to the heat generated by adsorption of evaporated fuel onto the activated carbon when the fuel tank is refueled. The tank-side adjacent region T is provided with an adsorbent containing at least one additive material selected from the group consisting of a phase-change substance having a phase-change temperature of 36°C or higher and a phase-change substance having a phase-change temperature of 36°C or higher. This is preferable because it prevents the temperature of the activated carbon from exceeding 35°C. Furthermore, since the adsorbent containing activated carbon is disposed in the tank-side adjacent region T, the amount of activated carbon stored in the adsorbent chamber R is prevented from decreasing, and the deterioration of adsorption performance can be prevented.

[0166] (2) In the above embodiment, the outer shape of the adsorbent 10 is a hollow cylinder, but the outer shape of the adsorbent 10 is not limited to this. The adsorbent 10 may be, for example, elliptical, rectangular, square, or the like.

[0167] (3) In the above embodiment, as shown in Fig. 4, the adsorbent chamber R is divided into three regions: the first region 31, the second region 32, and the third region 33. However, the region consisting of the second region 32 and the third region 33 may be divided into three or more regions instead of two. In this case as well, the region closest to the atmospheric port 25 is the atmospheric-side adjacent region U, and the adsorbent 10 of the above embodiment is disposed in the atmospheric-side adjacent region U.

[0168] (4) In the above embodiment, the adsorbent 10 of the above embodiment is disposed in the atmosphere-side adjacent region U, as in the canister 100 shown in Fig. 4. However, the adsorbent chamber R on the atmospheric port 25 side may be divided into multiple regions, and a combination of honeycomb adsorbent and honeycomb pellets of the adsorbent 10 may be disposed in each region. Such a canister will be described below with reference to FIG. In the canister 100 in Fig. 4, the right-hand space (the space on the atmospheric port 25 side) is divided into two parts, upper and lower, by a filter F, but in the canister 100 in Fig. 5, the right-hand space (the space on the atmospheric port 25 side) is divided into three parts, upper and lower, by a filter F. The rest of the configuration of the canister 100 in Fig. 5 is the same as that in Fig. 4.

[0169] In the space on the atmospheric port 25 side, from the lower side (the side remote from the atmospheric port 25), the lower space (the space on the cover 22 side) is a second region 32, the central space is a third region (atmosphere-side remote region) 33, and the upper space (the space on the atmospheric port 25 side) is a fourth region (atmosphere-side adjacent region U) 34. The space on the tank port 23 side, separated by the partition wall 26, is a first region 31. In this example, honeycomb adsorbents having a relatively large outer diameter D and length L of the adsorbent 10 are arranged in the fourth region 34, honeycomb pellets having a relatively small outer diameter D and length L of the adsorbent 10 are arranged in the third region 33, and activated carbon is arranged in the first region 31 and the second region 32. For example, an adsorbent 10 having an outer diameter D of 3.5 mm or more and 10 mm or less is sometimes called a honeycomb pellet, and an adsorbent 10 having an outer diameter of more than 10 mm and 40 mm or less is sometimes called a honeycomb adsorbent.

[0170] The second region 32, the third region 33, and the fourth region 34 are preferably adjacent to each other along the direction toward the atmospheric port 25. However, a separate space may be provided between at least the second region 32 and the third region 33, or between the third region 33 and the fourth region 34.

[0171] In this example, the honeycomb adsorbent of the adsorbent 10 and the honeycomb pellets of the adsorbent 10 are arranged in the fourth region 34 and the third region 33 in this order. The BWC of the honeycomb pellets among the adsorbent 10 disposed in the third region 33 and the BWC of the honeycomb adsorbent among the adsorbent 10 disposed in the fourth region 34 decrease in this order. In other words, the relationship of BWC of the honeycomb pellets among the adsorbent 10 (third region 33) > BWC of the honeycomb adsorbent among the adsorbent 10 (fourth region 34) is satisfied.

[0172] As described above, in this example, the honeycomb adsorbent of the canister adsorbent 10 is disposed in the atmosphere-side adjacent region U, which is the fourth region 34, and the honeycomb pellet of the canister adsorbent 10 is disposed in the third region 33. Desorption (purging) of evaporated fuel from the activated carbon (adsorbent) contained in the canister adsorbent 10 is performed by intake air from the purge port 24 and atmospheric air flowing in from the atmospheric port 25. The canister adsorbent 10 has excellent purging performance because the outer wall 10A and the ribs 10B are formed to be relatively thin. Therefore, by disposing the canister adsorbent 10 in the fourth region 34, which is the atmosphere-side adjacent region U in the canister 100, and the adjacent third region 33, the purging performance of the canister can be improved.

[0173] In this example, in particular, even if the BWC of the activated carbon disposed in the second region 32 is high and the butane adsorption performance is high, the DBL performance of the canister 100 can be enhanced by the honeycomb pellets and the honeycomb adsorbent disposed in each of the region from the second region 32 toward the atmosphere port 25, that is, the third region 33 (atmosphere-side separation region) 33 and the fourth region 34 (atmosphere-side adjacent region) 34. That is, even when the adsorption amount of butane increases due to the activated carbon disposed in the second region 32, since relatively small honeycomb pellets are disposed in the third region 33, the purge performance in the third region 33 can be enhanced due to the large outer surface area of the honeycomb pellets disposed in the third region 33, etc., and the DBL performance of the canister 100 can be enhanced. Further, since a relatively large honeycomb adsorbent is further disposed in the fourth region 34 adjacent to the third region 33, the adsorption of butane in the purged evaporated fuel can be suppressed in the fourth region 34, the purge performance of the canister 100 can be enhanced, and the DBL performance can be enhanced.

[0174] Further, in this example, in particular, the relationship of BWC of the honeycomb pellets in the adsorbent 10 > BWC of the honeycomb adsorbent in the adsorbent 10 (fourth region 34) is satisfied, and the BWC becomes smaller toward the atmosphere port 25. Therefore, the remaining amount of butane after purge becomes smaller toward the atmosphere port 25, and the performance of DBL is improved.

[0175] Furthermore, it is preferable that the canister adsorbent 10 contains at least one additive selected from the group consisting of a metal oxide, a phase transition material, and a phase transition material, because this suppresses temperature rise and fall of the adsorbent, such as activated carbon. That is, when evaporated fuel is desorbed from an adsorbent, such as activated carbon, heat is removed, causing the adsorbent's temperature to drop, resulting in a deterioration in purging performance. For example, if the temperature of the activated carbon adsorbent falls below 10°C, purging performance will be significantly reduced. According to the above configuration, the honeycomb adsorbent of the canister adsorbent 10 is disposed in the fourth region 34, which is the atmosphere-side adjacent region U adjacent to the atmospheric port 25 in the adsorbent chamber R, and the honeycomb pellet of the canister adsorbent 10 is disposed in the adjacent third region 33. This suppresses excessive temperature drops of the activated carbon contained in the canister adsorbent 10, ensuring proper purging.

[0176] In one embodiment, the canister 100 may be configured such that the fourth region 34 is provided with a honeycomb adsorbent of the adsorbent 10 of any one of Examples 1 to 13, the third region 33 is provided with honeycomb pellets of the adsorbent 10 of any one of Examples 1 to 13, and activated carbon is provided in the remaining first region 31 and second region 32. It is preferable that the honeycomb adsorbent and honeycomb pellets are configured from the adsorbent 10 of any one of Examples 2 to 6, 9, and 10 to 13, which has particularly excellent DBL performance. The DBL performance of such a canister 100 is considered to be particularly excellent in AA. [Explanation of symbols]

[0177] 10: Adsorbent 10A: Exterior wall 10B: Rib 10C: Cell

Claims

1. In a canister for evaporative fuel treatment having a tank port communicating with an upper chamber of a fuel tank of an internal combustion engine, a purge port communicating with an intake passage of the internal combustion engine, an atmosphere port open to the atmosphere, and an adsorbent chamber through which evaporative fuel flows from the tank port to the atmosphere port, a first adsorbent is disposed in an atmosphere-side adjacent region adjacent to the atmosphere port in the adsorbent chamber, a second adsorbent is disposed in an atmosphere-side separated region separated from the atmosphere port and adjacent to the atmosphere-side adjacent region, the first adsorbent and the second adsorbent comprise a cylindrical outer wall, and a plurality of ribs partitioning the outer wall into a plurality of cells along the axis of the outer wall, the thickness of the outer wall and the thickness of the plurality of ribs are less than 0.6 mm, and at least one of the thickness of the outer wall and the plurality of ribs exceeds 0.4 mm, the outer diameter of the outer wall is 3.5 mm or more and 40 mm or less, the BWC in the BWC evaluation method according to ASTM D5228 exceeds 3.0 g / dL, in the BWC evaluation method according to ASTM D5228, the purge efficiency represented by the following formula is 0.86 or more, Purge efficiency = (butane adsorption amount - butane retention amount) / butane adsorption amount... (1) the first adsorbent is configured to contain at least activated carbon, in the first adsorbent, a first pore having a diameter of less than 100 nm derived from the activated carbon and a second pore having a diameter of 1 μm or more derived from a meltable core are formed, and the volume of the second pore exceeds 0.05 mL / g and is 0.35 mL / g or less with respect to the mass of the first adsorbent, the first adsorbent disposed in the atmosphere-side adjacent region is a honeycomb adsorbent having an outer diameter of the outer wall exceeding 10 mm and 40 mm or less, the second adsorbent disposed in the atmosphere-side separated region is a honeycomb pellet having an outer diameter of the outer wall of 3.5 mm or more and 10 mm or less, a third adsorbent containing activated carbon having a BWC of 15.0 g / dL or more in the BWC evaluation method according to ASTM D5228, and at least one of a phase change material having a phase change temperature of 36°C or more and a phase transition material having a phase transition temperature of 36°C or more is disposed in a tank-side adjacent region adjacent to the tank port in the adsorbent chamber. A canister.

2. The canister according to claim 1, wherein the outer diameter of the outer wall is 3.5 mm or more and 10 mm or less.

3. The thickness of the outer wall and the thickness of the plurality of ribs are less than 0.45 mm, The canister according to claim 1, wherein the outer diameter of the outer wall exceeds 10 mm and is 40 mm or less.

4. The canister according to any one of claims 1 to 3, wherein the adsorbent contains 10% by mass or more and 70% by mass or less of a metal oxide with respect to the adsorbent.

5. The canister according to any one of claims 1 to 4, wherein each of the shapes of the plurality of cells is at least one of a triangular shape and a hexagonal shape when viewed in the axial direction.

6. The canister according to any one of claims 1 to 5, wherein the adsorbent has a difference in the equilibrium adsorption amount of n-butane concentration exceeding 35 g / L when the n-butane concentration is between 5 vol% and 50 vol%.

7. The canister according to any one of claims 1 to 6, wherein the adsorbent is configured to include at least activated carbon and a temperature control material having at least one of a volume specific heat and a thermal conductivity higher than that of the activated carbon.

8. The canister according to claim 7, wherein the temperature control material is at least one of a metal oxide, a phase change material having a phase change temperature of 36°C or lower, and a phase transition material having a phase transition temperature of 36°C or lower.

9. The canister according to any one of claims 1 to 8, wherein the number of cells of the plurality of cells is 200 cells / inch2 or more, and the number of ribs of the plurality of ribs is 4 or more.

10. The canister according to any one of claims 1 to 9, which satisfies the relationship of BWC of the honeycomb pellet > BWC of the honeycomb adsorbent.

11. A method for manufacturing the first adsorbent included in the canister according to any one of claims 1 to 10, mixing at least activated carbon, an organic binder, a crosslinking agent, and an inorganic material, and then kneading, forming the kneaded material into a molded body, performing a drying treatment on the molded body at 100°C or higher and 200°C or lower, A method for manufacturing an adsorbent.

12. A method for manufacturing the first adsorbent included in the canister according to any one of claims 1 to 10, mixing at least activated carbon, an organic binder, and an inorganic material, and then kneading, forming the kneaded material into a molded body, performing a firing treatment on the molded body at 700°C or higher and 900°C or lower, A method for manufacturing an adsorbent.

13. Furthermore, as the temperature control material having at least one of a volumetric specific heat and a thermal conductivity higher than that of the activated carbon, at least one of a metal oxide, a phase change material having a phase change temperature of 36°C or lower, and a phase transition material having a phase transition temperature of 36°C or lower is mixed and then kneaded, the method for producing an adsorbent according to claim 11 or 12.

14. Furthermore, a meltable core is mixed and then kneaded, the method for producing an adsorbent according to any one of claims 11 to 13.

15. Furthermore, a metal oxide of 10% by mass or more and 70% by mass or less with respect to the adsorbent is mixed and then kneaded, the method for producing an adsorbent according to any one of claims 11 to 14.

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