JP4795387B2 - Canister and manufacturing method thereof - Google Patents

Description

  The present invention relates to an evaporative fuel processing apparatus canister that prevents evaporative fuel generated from a fuel tank from being released into the atmosphere, and in particular, by utilizing latent heat together with an adsorbent capable of adsorbing and desorbing evaporative fuel. The thermal storage material which suppresses the temperature change of an adsorbent is related with the canister accommodated in the inside, and its manufacturing method.

  Conventionally, evaporative fuel generated by volatilization of gasoline fuel stored in a fuel tank while the vehicle is stopped, etc. is adsorbed and captured by an adsorbent made of activated carbon, etc., to prevent the evaporated fuel from being released into the atmosphere. There is a canister for the fuel processor. The canister is provided with a tank port communicating with the upper part of the fuel tank, an atmospheric port whose tip is open to the atmosphere, and a purge port through which evaporated fuel desorbed (purged) from the adsorbent flows. It has been. Evaporated fuel generated when the temperature of the fuel tank rises when the engine is driven or when the vehicle is stopped is adsorbed by the adsorbent while flowing from the tank port into the canister and flowing toward the atmospheric port. Thus, the evaporated fuel is prevented from being released into the atmosphere. The evaporated fuel adsorbed by the adsorbent is desorbed (purged) by introducing air from the air port by an intake pipe negative pressure when the engine is driven and a suction pump that is driven and controlled independently of the engine drive. The adsorbent is regenerated.

  At this time, the fuel vapor is liquefied when adsorbed on the adsorbent in the canister, and vaporizes again when desorbed from the adsorbent. Therefore, when the evaporated fuel is adsorbed, the temperature of the adsorbent increases due to condensation heat that is an exothermic reaction, and when the evaporated fuel is desorbed, the temperature of the adsorbent decreases due to vaporization heat that is an endothermic reaction. On the other hand, the adsorbent that is a porous body has a characteristic that the adsorption capacity increases as the temperature decreases, and the adsorption capacity decreases as the temperature increases. Therefore, it is desirable that the temperature of the adsorbent is low when the evaporated fuel is adsorbed and the temperature of the adsorbent is high when purging. However, the heat generation / heat absorption accompanying the phase change of the evaporated fuel occurs in the direction opposite to the desirable temperature state of the adsorbent, that is, in the direction of inhibiting the adsorption / desorption performance of the adsorbent. Therefore, in order to improve the adsorption / desorption performance of the adsorbent, it is desired to suppress heat generation / endotherm associated with the phase change of the evaporated fuel to suppress the temperature change of the adsorbent.

  Therefore, there are Patent Document 1 and Patent Document 2 as canisters in which a heat storage material that suppresses the temperature change of the adsorbent using latent heat is housed together with the adsorbent. In the heat storage material of Patent Document 1, a microcapsule in which a phase change material made of paraffin such as tetradecane or pentadecane having a relatively low melting point is encapsulated in an outer shell made of melamine resin or the like, or a pelletized granule (molded) A heat storage body). In this way, the heat storage material as well as the adsorbent material is accommodated in the canister, so that the temperature rise of the adsorbent material when the evaporated fuel is adsorbed, the phase change material in the heat storage material is changed from the solid phase to the liquid phase. While the temperature of the adsorbent is reduced when the evaporated fuel is desorbed, the latent heat when the phase change material in the heat storage material changes from a liquid phase to a solid phase By being suppressed by (solidification heat), the adsorption / desorption performance of the adsorbent is improved.

  Patent Document 2 is a canister previously proposed by the applicant of the present invention. In order to prevent the vaporized fuel from passing through the outer shell constituting the microcapsule and preventing the melting point of the phase change material from changing, it is compared with the adsorbent. The phase change material is directly or indirectly covered with a material that has high thermal conductivity and does not allow vaporized fuel to pass therethrough. Specifically, a phase change substance or a microcapsule enclosing a phase change substance is accommodated in a pellet-shaped metal case (Claims 6 to 7, paragraphs 0060 to 0062), or a resin film laminated with a metal foil. A phase change substance or microcapsules are accommodated in a pellet-like case (Claim 8, paragraphs 0063 to 0064), or a metal material is plated or deposited on the outer surface of the microcapsules (Claim 9, paragraph 0065). Examples of the metal that does not allow the evaporative fuel to permeate include aluminum, copper, iron, and stainless steel (Table 1), and a pellet-shaped metal container and the like are dispersed throughout the adsorption chamber together with the adsorbent.

JP-A-2005-233106 Japanese Patent Laid-Open No. 2006-233962

By the way, in recent years, as part of measures against global warming, legislation has been internationally implemented in which plant-derived alcohol called biomass ethanol or bioethanol is mixed with conventional gasoline and used as fuel for automobiles. Gasoline mixed with ethanol is sometimes called a gas hole. In addition, biogasoline in which ethyl tertiary butyl ether (ETBE) obtained by reacting plant-derived ethanol and isobutene is mixed with general gasoline by several percent is being used. As a raw material for biomass ethanol, plant resources containing a large amount of sugar or starch are considered suitable. At present, molasses derived from sugarcane (mainly South America), corn (mainly US), and sugar beet (mainly main ingredients) Europe) is the main raw material. In addition, development of biomass ethanol using sorghum (sorghum, sorghum), potato, sweet potato, wheat and the like as a raw material is also underway. Since these plants absorb CO ₂ in the atmosphere, the absolute amount of CO _{2 on} the entire earth will not increase even if the fuel from the plant raw material is burned and converted to CO _2. Based on (carbon neutral). Thus, when the alcohol mixed fuel is used in the vehicle, the evaporated fuel contains a volatilized alcohol component.

  In patent document 1, the thermal storage material microcapsule is accommodated with the adsorbent in the canister, so that the temperature change of the adsorbent due to the adsorption / desorption of the evaporated fuel is effectively suppressed. However, since the outer shell made of melamine resin has low alcohol resistance, there is a problem when it is used for adsorption / desorption of evaporative mixed fuel from alcohol mixed fuel, especially when deteriorated alcohol mixed fuel is used. There is a fear. That is, when the alcohol-mixed fuel deteriorates and organic acids, peroxides, etc. increase, these deteriorated components have a function of cutting the cross-links of the melamine resin that forms the outer shell of the microcapsule, and the cross-linking degree of the melamine resin is increased. The phase change material in the microcapsule may leak due to the decrease. If the phase change material leaks out of the microcapsule, the latent heat by the heat storage material microcapsule is reduced and a predetermined heat storage effect cannot be exhibited, and the performance of the adsorbent is deteriorated.

  On the other hand, in Patent Document 2, a phase change material or a microcapsule containing a phase change material is stored in a metal container or the like. Patent Document 2 does not focus on the case where an alcohol-mixed fuel is used. However, the metal material has higher alcohol resistance than the melamine resin, and the above problem hardly occurs. However, since Patent Document 2 uses only one kind of heat storage material using metal, it has the following problems. First, it is inevitable that such a heat storage material is expensive as compared with a conventional heat storage material, and if it is dispersed to a portion where alcohol does not exist so much, the cost is wasted. Secondly, the specific gravity of the metal material is considerably higher than that of the resin material. Therefore, if the heat storage material in which the phase change material is stored in a container or the like using metal is dispersed over the entire adsorption chamber in the canister, the weight of the canister is greatly increased. In order to solve such a problem, even if the heat storage material is accommodated only in a predetermined range where alcohol resistance is particularly required, if only one kind of heat storage material is used, the adsorbent in other parts is not used. The temperature change suppressing effect cannot be obtained.

  Therefore, the present inventors use a heat storage material having high alcohol resistance that does not leak phase change substances even when alcohol mixed fuel is used, while ensuring the temperature suppressing effect over the entire adsorption chamber, the weight of the canister As a result of diligent investigation on whether or not a significant increase in cost is unavoidable, alcohol is more easily adsorbed on the adsorbent than evaporative fuel, and this indicates that the distribution of alcohol adsorbed in the adsorbent chamber has certain characteristics. Knowing and effectively utilizing the characteristics of the alcohol distribution, the above problems can be solved by accommodating two types of heat storage materials with different alcohol resistance in appropriate locations, and can be easily separated and stored by using the specific gravity difference. As a result, the present invention has been completed. That is, this invention solves the said subject, The place made into the objective efficiently accommodates two types of heat storage materials from which alcohol resistance and specific gravity differ in the suitable place according to the alcohol distribution in adsorption | suction chamber. Therefore, a canister that does not increase the canister weight and cost while ensuring the temperature suppressing effect over the entire adsorption chamber without causing a phase change material to leak from the heat storage material even when alcohol mixed fuel is used. Provided is a method for manufacturing a canister capable of easily separating and storing two types of heat storage materials.

  The present invention provides a microcapsule type in which an adsorbent that adsorbs / desorbs evaporated fuel and a phase change material that absorbs / releases latent heat in response to a temperature change are enclosed in an outer shell made of synthetic resin in an adsorption chamber. In a canister that contains a heat storage material and a tank port that communicates with the fuel tank and an atmospheric port that communicates with the atmosphere, when alcohol-mixed fuel is used, alcohol is more easily adsorbed by the adsorbent than evaporative fuel Therefore, the alcohol distribution is characterized in that a large amount of alcohol is adsorbed near the tank port in the adsorption chamber of the canister and almost no alcohol is adsorbed near the air port. That is, in the adsorption chamber, two types of heat storage materials having different alcohol resistance are accommodated separately on the tank port side and the atmospheric port side, and the tank port side portion in the adsorption chamber is provided with the atmospheric port side. A heat storage material having higher alcohol resistance than that of the heat storage material stored in the part is stored. The heat storage material accommodated in the atmospheric port side portion may be basically the same as a conventional general heat storage material. Or as long as a weight and cost are equivalent to the conventional heat storage material, the heat storage material which has alcohol resistance to some extent can also be used.

  As the heat storage material having high alcohol resistance accommodated in the tank port side portion, the outer shell of the heat storage material is made of a synthetic resin having higher alcohol resistance than the outer shell of the heat storage material accommodated in the atmosphere port side portion. The outer shell of the heat storage material housed in the tank port side portion and the outer shell of the heat storage material housed in the atmospheric port side portion are made of the same synthetic resin, and the tank port side portion The outer shell of the stored heat storage material can be coated with a synthetic resin having high alcohol resistance.

  It is preferable that the heat storage material with high alcohol resistance is accommodated in at least a range of 20% on the tank port side in the adsorption chamber, and at most in a range of 70% on the tank port side in the adsorption chamber.

  It is preferable that the two kinds of heat storage materials are formed by granulating a plurality of microcapsules into a granule with a binder, or granulating and forming a plurality of microcapsules into a granule with a binder together with a powdery adsorbent.

  The canister of the present invention is suitably used for adsorption / desorption of an evaporative mixed fuel produced from a fuel mixed with alcohol.

  Further, according to the present invention, the adsorbent that adsorbs / desorbs the evaporated fuel in the adsorption chamber in the hollow cylindrical canister case, and the absorption / release of latent heat according to the temperature change in the outer shell made of synthetic resin. A canister having a tank port communicating with a fuel tank and an air port communicating with the atmosphere provided at a position opposite to the tank port A manufacturing method can also be provided. The canister manufacturing method includes a step of mixing and filling the adsorbent and two kinds of heat storage materials having different specific gravity and alcohol resistance in the canister case, and the atmospheric port and the tank port are top and bottom. And a step of applying vibration to the canister case in a state of being in a direction.

  According to the present invention, the two types of heat storage materials with different alcohol resistance are separately stored in place, so that the temperature suppression effect over the entire adsorption chamber is ensured and the canister weight and cost do not increase. Canister can be obtained. That is, since the heat storage material having high alcohol resistance is efficiently disposed only in the tank port side portion where the amount of alcohol adsorbed is large, it is possible to prevent the phase change material from leaking out of the heat storage material in that portion. In addition, since the alcohol resistance is secured by the resin, the weight and cost of the canister are not significantly increased as in the case of using a metal material, and the weight and cost of the canister can be reduced depending on the resin used. is there. At the same time, other parts where alcohol resistance is not required, i.e., the atmospheric port side part, also contains a general heat storage material that does not have high alcohol resistance, so the temperature of the adsorbent can be changed throughout the adsorption chamber. Can be suppressed. In addition, since there is almost no alcohol on the atmosphere port side, even if a heat storage material that does not have high alcohol resistance is accommodated in the part, there is no fear that the phase change material leaks out.

  Of the two types of heat storage materials, the outer shell of one heat storage material is made of a highly alcohol-resistant synthetic resin, or the outer shells of two types of heat storage material are made of the same synthetic resin. If the outer shell is covered with a synthetic resin having high alcohol resistance, the specific gravity is smaller than that in the case of using a metal material, so that it is possible to avoid or reduce the weight of the canister.

  If the heat storage material having high alcohol resistance is accommodated in at least 20% of the tank port side, which is the minimum required range particularly requiring alcohol resistance, the canister weight and cost can be reduced greatly. On the other hand, if the heat storage material with high alcohol resistance is accommodated in the range of 70% on the tank port side, the phase change material can be reliably prevented from leaking out of the heat storage material.

  If a microcapsule heat storage material or powdered adsorbent is granulated with a binder, the space between each heat storage material and each adsorbent is better than when microcapsules and adsorbents are stored as they are. Increases, and good air permeability can be secured.

  When manufacturing a canister with a straight channel with tank ports and atmospheric ports facing each other, adsorbent and two types of heat storage materials with different specific gravity and alcohol resistance are mixed in the canister case at the same time. If the canister case is vibrated with the atmosphere port and the tank port facing upside down after filling, the heat storage material with a large specific gravity moves downward along with the vibration, inevitably two kinds of heat storage materials Since it is separated into two layers, it is easy to manufacture.

<Alcohol adsorption characteristics confirmation test>
Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited thereto, and various modifications can be made without departing from the scope of the present invention. First, the test results of examining the alcohol adsorption characteristics as the basic principle of the present invention will be described. This test includes an adsorption chamber 103 on the tank port 102 side and an adsorption chamber 105 on the atmosphere port 104 side, which are partitioned by a partition wall 101, as shown in FIG. A 1 L canister 100 was used. The purge port 106 was sealed. In the canister 100, 0.9 L of wood-based crushed coal was accommodated. Gasoline (E10) mixed with 10% ethanol is heated in an oil tank, and sufficient fuel is produced by evaporating gasoline and ethanol, and introduced into the tank port of the canister at 15 g / min for 4 minutes. Adsorbed to the material. Next, 540 L of air at a flow rate of 20 L / min was introduced into the canister by a pump from the atmosphere port side, and the evaporated mixed fuel adsorbed by the adsorbent was desorbed. This adsorption / desorption operation was repeated until the canister weight after desorption was stabilized, thereby stabilizing the amount of evaporated fuel and alcohol remaining in the adsorbent. When the remaining amounts of the evaporated fuel and alcohol are stabilized in this way, the vicinity A of the tank port 102, the central bottom B of the canister 100, which is an intermediate portion between the tank port 102 and the atmospheric port 104, and the atmospheric port 104 as shown in FIG. 25 ml of activated carbon was taken out from each part in the vicinity C, and the adsorbents A to C at each part were heated to about 300 ° C. to evaporate the remaining evaporated fuel and the remaining alcohol, and were cooled and liquefied. The amount of each component contained in the obtained liquid was measured by gas chromatography.

  As a result of the above test, the activated carbon A in the vicinity of the tank port 102 has an evaporative mixed fuel of 9.52 g / dL, and the activated carbon B in the center bottom of the canister 100 has an evaporative mixed fuel of 6.19 g / dL in the vicinity of the atmospheric port 104. In the activated carbon C, 1.57 g / dL of the evaporative mixed fuel remained. As a result, it was found that the canister 100 has the largest amount of adsorbed mixed fuel adsorbed near the tank port 102 and the amount of adsorbed mixed fuel tends to decrease as it approaches the vicinity of the atmospheric port 104.

  The content of each component by gas chromatography is shown in FIG. Note that “C” in FIG. 2 indicates the number of carbon atoms of the hydrocarbon, and for the activated carbon C on the air port 104 side, the remaining amount of the evaporated and mixed fuel was too small to be measured. From the results shown in FIG. 2, the majority of the evaporated and mixed fuel adsorbed by the adsorbent A in the vicinity of the tank port 102 was ethanol. On the other hand, most of the evaporative mixed fuel adsorbed on the activated carbon B at the center bottom was hydrocarbon. As a result, it was found that alcohol was preferentially adsorbed by the adsorbent as compared with the evaporated fuel, and the most alcohol was adsorbed in the vicinity of the tank port. The reason why hydrocarbons having 3 to 6 carbon atoms do not exist is that these components are more easily desorbed than hydrocarbons having 7 or more carbon atoms during purging and that they are replaced with hydrocarbons having 7 or more carbon atoms during adsorption. It is done. Also, the number of hydrocarbons with 9 or more carbon atoms is greater in the center bottom than in the vicinity of the tank port because a large amount of alcohol is adsorbed near the tank port and hydrocarbons with 9 or more carbon atoms are difficult to adsorb. This is thought to be due to the deep inside.

Example 1
FIG. 3 is a sectional view of the canister 1 according to the first embodiment of the present invention. The canister 1 of the first embodiment is installed in an evaporative fuel processing device generated from a fuel tank of an automobile, and as shown in FIG. 3, a canister case 10 made of a synthetic resin and having a hollow cylindrical shape, And a cover 11 made of synthetic resin that closes the upper surface opening of the canister case 10. The canister case 10 and the cover 11 are made of the same synthetic resin material such as nylon, and in a state where the flanges 10a and 11a integrally formed on the outer peripheral surfaces of both the ends 10 and 11 are attached to each other, For example, they are joined by vibration welding or adhesion. The cover 11 is integrally formed with a cylindrical tank port 13 serving as an evaporative fuel introduction portion and a cylindrical purge port 14 through which the desorbed evaporative fuel flows. . On the other hand, on the lower surface of the canister case 10 opposite to the tank port 13 and the like, a cylindrical atmospheric port 15 that communicates with the atmosphere and serves as an inlet / outlet of the atmosphere (air) penetrates the inside and outside of the tank so as to face the tank port 13 and the like. Are integrally formed. Thus, the canister 1 has one adsorption chamber 21 in which a substantially straight flow path extending between the tank port 13 and the purge port 14 and the atmospheric port 15 is formed. Although not shown, the tank port 13 communicates with the upper part of the fuel tank, and the purge port 14 communicates with the intake pipe of the engine (internal combustion engine) or is driven and controlled independently of the engine drive. The fuel tank communicates with the suction pump.

  Air-permeable filters 17, 17 and plates 19 u, 19 l are arranged above and below the canister case 10, and the space between the upper and lower filters 17, 17 serves as an adsorption chamber 21. And in the said adsorption | suction chamber 21, the two types of heat storage materials 22 and 23 which differ in alcohol resistance and specific gravity are separated into the upper and lower layers with the adsorbent 18 which can adsorb | suck and desorb the evaporative fuel. Separately accommodated at. The filter 17 is made of a synthetic resin nonwoven fabric or urethane foam. For the plate 19, a metal plate having a large number of pores, a metal mesh, or the like is used. The lower plate 19l is received by a step portion 10b provided at the lower portion of the canister case 10. Between the upper plate 19u and the cover 11, a coil spring 20 that constantly urges the plate 19u toward the atmospheric tank port 15 is disposed. Due to the urging force of the coil spring 20, the adsorbent 18 and the two types of heat storage materials 22 and 23 are securely accommodated without variation.

  Activated carbon is used as the adsorbent 18, and fine powdery activated carbon is granulated and formed into a predetermined shape with a binder resin. The adsorbent 18 is distributed and accommodated throughout the adsorption chamber 21. The heat storage material is adsorbed by the heat storage material 22 which is not mixed with the adsorbent 18 in the adsorbing material 18 in the air port 15 side portion in the adsorption chamber 21 and the tank port 13 side portion in the adsorption chamber 21. A heat storage material 23 which is accommodated in a mixed and dispersed manner with the material 18 and has a higher alcohol resistance and a lower specific gravity than the heat storage material 22 is used. The heat storage material 22 not having high alcohol resistance is the same as a conventionally known heat storage material, and as shown in FIG. 4, in a hollow spherical outer shell 25 (microcapsule) made of melamine resin (MF), A fine microcapsule type heat storage material 22a encapsulating a phase change material 24 that absorbs and releases latent heat according to temperature changes is used, and a large number of microcapsule type heat storage materials 22a are granulated and formed into a predetermined shape by a binder resin. Has been. The average particle diameter of the microcapsule type heat storage material may be about 0.1 to 25 μm, and the phase change material 24 may be enclosed by about 70 to 100% with respect to the internal volume of the outer shell 25. Moreover, it is preferable to use a melamine resin having a specific gravity as high as possible. The microcapsule type heat storage material 22a can be manufactured by a known method such as a coacervation method or an in-situ method (interface reaction method) using the phase change material 24 as a core material. When manufactured by the interfacial reaction method, the outer shell 25 is formed so as to cover the outer peripheral surface of the phase change material 24, so that the phase change material 24 is 100% sealed with respect to the inner volume of the outer shell 25. It becomes.

The phase change material 24 is not particularly limited as long as it is a material that can change between a solid phase and a liquid phase in accordance with the temperature change of the adsorbent 18, and is not limited to an organic compound or inorganic material having a melting point of about 10 to 80 ° C. Compounds can be used. Specifically, linear aliphatic hydrocarbons such as tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosan, heicosan, docosan, natural wax, petroleum wax, LiNO ₃ 3H ₂ O, Na ₂ SO ₄・ Hydrates of inorganic compounds such as 10H ₂ O and Na ₂ HPO ₄ · 12H ₂ O, fatty acids such as capric acid and lauric acid, higher alcohols having 12 to 15 carbon atoms, methyl valmitate, methyl stearate, etc. And the like. Among them, it is preferable to use a phase change material having a melting point of about 20 ° C. Examples of such a phase change material include hexadecane having a melting point of 18 ° C. and heptadecane having a melting point of 22 ° C. These phase change materials may be used alone or in combination of two or more. Although various thermosetting resins can be used as the binder resin, a phenol resin or an acrylic resin is preferable from the viewpoint of temperature and strength required as a final canister.

  The granulated heat storage material 22 is preferably in the form of a pellet (columnar shape) having a diameter of about 1 to 3 mm and a length of about 1 to 5 mm as shown in FIG. The pellet-shaped granulated heat storage material 22 is obtained, for example, by kneading a large number of microcapsules 22a and a binder resin, and cutting an extruded long cylindrical molded body into a predetermined size. It is preferable that the granulated adsorbent 18 has the same shape and the same size as the granulated heat storage material 22. More preferably, the granulated adsorbent 18 and the granulated heat storage material 22 have the same dimensions. The pelletized granulated adsorbent 18 can also be granulated by the same method as the granulated heat storage material 22. If the granulated adsorbent 18 and the granulated heat storage material 22 are the same or the same size, when they are mixed and dispersed in the adsorption chamber 21, they are appropriately placed between the granulated adsorbent 18 and each granulated heat storage material 22. Therefore, good air permeability is ensured and pressure loss and adsorption / desorption are not impaired. The granulated adsorbent 18 and the granulated heat storage material 22 can also have other spherical shapes, polygonal shapes, flat shapes, and the like. The granulated heat storage material 22 is preferably mixed and accommodated in a volume ratio of 5 to 40% with respect to the entire volume of the granulated adsorbent 18. When the total volume of the granulated heat storage material 22 is less than 5% with respect to the total volume of the granulated adsorbent 18, the effect of suppressing the temperature change of the adsorbent 18 due to the heat storage action cannot be sufficiently obtained. On the contrary, when the total volume of the granulated heat storage material 22 exceeds 40% with respect to the total volume of the granulated adsorbent 18, the accommodation rate of the adsorbent 18 is reduced. As a result, the adsorption amount per unit volume of the canister 1 is decreased. descend.

  The heat storage material 23 with high alcohol resistance has basically the same configuration as that of the heat storage material 22 and is made of a synthetic resin in a hollow sphere-shaped outer shell 25 (microcapsule). A fine microcapsule type heat storage material 23a in which a phase change material 24 similar to the heat storage material 22 that generates absorption / release is enclosed is used, and a large number of microcapsule type heat storage materials 23a are granulated and formed into a predetermined shape by a binder resin. ing. The manufacturing method, the shape and preferred dimensions of the granulated molded body, the preferred mixing ratio with the adsorbent 18, and the like are the same as those of the heat storage material 22. However, the difference from the heat storage material 22 is that the outer shell 25 is made of a synthetic resin having high alcohol resistance such as phenol resin (PF), polyphenylene sulfide resin (PPS), polypropylene resin (PP), polyethylene resin (PE). It is said that. The synthetic resin with high alcohol resistance that forms the outer shell 25 may be used alone or in combination of two or more. Polypropylene resins and polyethylene resins have no particular problem in use because they have a particularly low specific gravity among synthetic resins, but when using a phenol resin or a polyphenylene sulfide resin, the specific gravity should be as small as possible.

  Alternatively, after the outer shell 25 is made of the same melamine resin as the heat storage material 22, as shown in FIG. 6, the outer surface of the outer shell 25 may be covered with the coating layer 26 made of the above-described synthetic resin having high alcohol resistance. it can. The coating layer 26 can be formed on the outer surface of the outer shell 25 by coating, spraying, or an interfacial reaction method. When forming the coating layer 26, the thickness of the outer shell 25 of the heat storage material 23 is made thinner than the thickness of the outer shell 25 of the heat storage material 22, and the coating layer 26 is thicker than the thickness of the outer shell 25 of the heat storage material 23. It is preferable to do. The total thickness of the outer shell 25 and the coating layer 26 in the heat storage material 23 is preferably approximately the same as the thickness of the outer shell 25 of the heat storage material 22. In this case, it is preferable to use a melamine resin for the heat storage material 23 having a specific gravity smaller than that of the melamine resin for the heat storage material 22.

  Furthermore, after making the heat storage agent 22 with low alcohol resistance into a granulation heat storage agent as shown in FIG. 5 with a binder resin, synthesis with high alcohol resistance is performed on the outer surface of the granulation heat storage agent 22 with low alcohol resistance. The resin can also be coated by application, spraying, or the like.

  The heat storage material 23 with high alcohol resistance is in a range from 20% on the tank port 13 side to 70% on the tank port 13 side with respect to the length of the adsorption chamber 21, and the canister 1 based on the alcohol content in the alcohol mixed fuel. What is necessary is just to accommodate suitably according to distribution of the alcohol adsorbed in the inside. If the alcohol content in the alcohol-mixed fuel is low, the range in which the alcohol is adsorbed is a small part on the tank port 13 side, and therefore the accommodation range of the heat storage material 23 may be narrow. Conversely, if the alcohol content in the alcohol-mixed fuel is high, the range in which the alcohol is adsorbed also extends to the back of the atmosphere port 15 side, so that the storage range of the heat storage material 23 is also widened. The heat storage material 22 is accommodated in other parts in the adsorption chamber 21. That is, the storage range of the heat storage material 22 is stored in the range of 80% from the atmosphere port 15 side to 30% from the atmosphere port 15 side according to the storage range of the heat storage material 23. When the storage range of the heat storage material 23 is narrower than the 20% range on the tank port 13 side (the storage range of the heat storage material 22 is wider than 80% on the air port side), the heat storage material 22 is exposed to alcohol, The risk of the phase change material 24 leaking out of the outer shell 25 increases. Conversely, if the storage range of the heat storage material 23 is wider than the 70% range on the tank port 13 side (the storage range of the heat storage material 22 is narrower than 30% on the air port side), the amount of use of the heat storage material 23 is more than necessary. The weight and cost of 1 are unnecessarily increased. Preferably, the storage range of the heat storage material 23 is in the range of 25% from the tank port 13 side to 60% in the tank port 13 side, and more preferably in the range of 30% to 50% from the tank port 13 side. In the present Example 1, the heat storage material 22 and the heat storage material 23 were accommodated in two equal parts in the range of the air port side 50% and the tank port side 50%.

  Next, a method for manufacturing the canister 1 will be described with reference to FIG. First, as shown in FIG. 7 (a), the canister case 10 manufactured by a known method such as injection molding is held in a state where the atmospheric port 15 is erected so that the atmospheric port 15 is downward. After arranging the plate 19l and the filter 17 in this order on the bottom, the adsorbent 18 and the two types of heat storage materials 22 and 23 are mixed and filled simultaneously into the canister case 10 from the top opening. At this time, as shown in FIG. 7B, the heat storage material 22 and the heat storage material 23 are not separated. Then, vibration is applied to the canister case 10 from this state. Then, the heat storage material 22 having a large specific gravity moves downward on the atmosphere port 15 side, and the heat storage material 23 having a small specific gravity moves upward on the rear tank port 13 side, as shown in FIG. The two types of heat storage materials 22 and 23 are naturally separated into predetermined amounts. When the heat storage material 22 and the heat storage material 23 are separated, finally, as shown in FIG. 7D, the filter 17, the plate 19u, and the coil spring 20 are arranged in this order, and the canister case 10 The canister 1 can be obtained by closing the upper surface opening with the cover 11.

  Next, the operation of the canister 1 according to the first embodiment will be described. In the present Example 1, the case where the alcohol mixed fuel in which the biomass ethanol derived from plants, such as sugarcane, molasses, corn, sugar beet, sorghum, potato, sweet potato, and wheat is mixed with several to several tens of percent gasoline is assumed. To explain. The alcohol mixing ratio of the alcohol mixed fuel that is currently in practical use is about 1 to 20 vol%. Specifically, gasoline (E10) in which less than 10% by volume of ethanol is mixed is used in the United States, and gasoline in which 20% by volume of ethanol (E20) is mixed in Brazil. In Japan, if the mixing ratio of ethanol is 3 vol% (E3) or less, it is safe to use in automobiles.

  When the temperature of the fuel tank rises due to the high-temperature atmosphere when the vehicle is stopped or the engine drive heat when the vehicle is running, the temperature of the alcohol-mixed fuel stored in the fuel tank also rises, causing gasoline volatile components (hydrocarbons) and A large amount of evaporative mixed fuel mixed with alcohol volatile components is generated. The evaporative mixed fuel generated in the fuel tank is introduced into the canister 1 from the tank port 13 and flows in the adsorption chamber 21 linearly toward the atmospheric port 15 and is accommodated in the adsorption chamber 21 during that time. The adsorbent 18 is adsorbed. At this time, the evaporative fuel mixture is liquefied when adsorbed on the adsorbent 18. Then, the temperature of the adsorbent 18 rises due to the heat of solidification of the evaporative fuel mixture, and the adsorption capacity (adsorption capacity) decreases as it is. However, since the heat storage materials 22 and 23 are accommodated in the adsorption chamber 21 together with the adsorbent 18, the phase change material 24 in the heat storage materials 22 and 23 changes from the solid phase to the liquid phase due to the temperature rise of the adsorbent 18. The temperature change of the adsorbent 18 is suppressed because the heat absorption due to the latent heat is generated.

  However, if the heat storage material has a conventional melamine resin outer shell, the degree of cross-linking of the melamine resin is reduced by organic acids or peroxides in the alcohol-mixed fuel, and phase change substances may leak from the heat storage material. There is. Here, since alcohol is more easily adsorbed by the adsorbent 18 than hydrocarbons, the alcohol is most adsorbed in the vicinity of the tank port 13, and the amount of alcohol adsorbed decreases as it approaches the atmospheric port 15, and near the atmospheric port 15. It is hardly adsorbed. On the other hand, hydrocarbons are not so adsorbed in the vicinity of the tank port 13, and are most adsorbed in the vicinity of the intermediate portion of the adsorption chamber 21, and the amount of adsorption tends to decrease as the air port 15 is approached. Therefore, in the first embodiment, the heat storage material 23 with high alcohol resistance is disposed only in a predetermined range on the tank port 13 side in the adsorption chamber 21 so that the phase change material can be efficiently leaked. And it is definitely prevented. On the other hand, since almost no alcohol is adsorbed in the vicinity of the atmospheric port 15, the heat storage material 22 similar to the conventional one is accommodated in a predetermined range on the atmospheric port 15 side.

  When the inside of the canister 1 becomes a negative pressure by the intake pipe negative pressure or the suction pump, the atmosphere (outside air) is sucked from the atmosphere port 15 and the evaporated mixed fuel adsorbed by the adsorbent 18 is desorbed (purged). It flows in the opposite direction to that and is discharged from the purge port 14. At this time, the evaporative mixed fuel is vaporized when desorbed from the adsorbent 18. Then, the temperature of the adsorbent 18 decreases due to the heat of vaporization of the evaporated and mixed fuel, and the adsorption capacity (adsorption capacity) decreases as it is. However, since the temperature change of the adsorbent 18 causes the phase change material 24 in the heat storage materials 22 and 23 to change from a liquid phase to a solid phase and generate heat due to latent heat, an increase in the temperature of the adsorbent 18 is suppressed. .

(Example 2)
FIG. 8 is a sectional view of a canister 2 according to the second embodiment of the present invention. The second embodiment is a modification of the first embodiment, in which the heat storage material 23 of the present invention is arranged in the canister 2 having a U-shaped flow path inside. Therefore, the following description will focus on differences from the first embodiment. Specifically, as shown in FIG. 8, the canister 2 according to the second embodiment includes a hollow cylindrical canister case 30 and a cover 31 that closes the bottom opening of the canister case 30. In the canister 2 according to the second embodiment, a tank port 33, a purge port 34, and an atmospheric port 35 are integrally formed on the upper surface of the canister case 30 in this order. A long partition wall 37 extending vertically from the upper surface of the canister case 30 to the vicinity of the cover 31 is integrally formed between the purge port 34 and the atmospheric port 35. By the partition wall 37, the inside of the canister 2 is partitioned into a first adsorption chamber 38 on the tank port 33 side and a second adsorption chamber 39 on the atmospheric port 35 side. As a result, a U-shaped flow path in which the tank port 33, the purge port 34 and the atmospheric port 35 communicate with each other via the lower side of the partition wall 37 is formed in the canister 2. Therefore, the first adsorption chamber 38 and the second adsorption chamber 39 are in a serial relationship with the flow direction of the evaporated fuel. A short auxiliary partition 40 extending from the upper surface of the canister case 30 toward the cover 31 is also integrally formed between the tank port 33 and the purge port 34.

  Then, the granulated adsorbent 18 and the heat storage material 23 with high alcohol resistance are mixed and accommodated in the entire first adsorption chamber 38 as in the first embodiment. On the other hand, the same granulated adsorbent 18 and granulated heat storage material 22 as in the first embodiment are mixedly dispersed and accommodated in the entire second adsorption chamber 39. Further, a filter 41 is arranged above and below the first adsorption chamber 38 and the second adsorption chamber 39, and a plate 42 arranged on the lower surface of the lower filter 41 is always upward (each port) by a coil spring 43. 33 to 35 side), the adsorbent 18 and the heat storage materials 22 and 23 are securely held. A filter 41 is also interposed in the upper and lower intermediate portions of the second adsorption chamber 39. Others are the same as those in the first embodiment, and a description thereof will be omitted.

(Other variations)
In the first and second embodiments, the adsorbent 18 granulated into a predetermined shape and the heat storage materials 22 and 23 are mixed and accommodated. However, the present invention is not limited to this, and the microcapsules 22a and 23a After knead | mixing a powdery activated carbon, you may granulate and shape together with binder resin. According to this, the trouble of manufacturing the granulated adsorbent 18 and the granulated heat storage materials 22 and 23 separately can be saved. In the second embodiment, the heat storage material 23 can be accommodated below the filter 41 of the second adsorption chamber 39.

  In the first embodiment, two types of heat storage agents 22 and 23 having different specific gravities are filled in the canister case 10 at the same time, and vibration is applied to classify them up and down. However, one of the heat storage agents 22 and the activated carbon 18 is placed in place. After the fixed amount is mixed and filled into the canister case 10, a predetermined amount of the other heat storage agent 23 and the activated carbon 18 may be mixed and filled into the canister case 10 from above.

It is a schematic block diagram of the test canister used for the adsorption characteristic confirmation test of alcohol. It is a graph which shows content of the evaporative mixing fuel component by a gas chromatography. 2 is a cross-sectional view of a canister according to Embodiment 1. FIG. It is a partial cross section top view of a microcapsule. It is a perspective view of a granulation heat storage material. It is a partial cross section top view of a heat storage material microcapsule with high alcohol resistance. FIG. 3 is a manufacturing process diagram of the canister of Example 1. 6 is a cross-sectional view of a canister according to Embodiment 2. FIG.

Explanation of symbols

1.2 Canister 10/30 Canister case 11/31 Cover 13/33 Tank port 14/34 Purge port 15/35 Atmospheric port 18 Adsorbent 21 Adsorption chamber 22 Heat storage material not having high alcohol resistance 23 Heat storage having high alcohol resistance Material 24 Phase change material 25 Outer shell 38 First adsorption chamber 39 Second adsorption chamber

Claims (8)

An adsorbent that adsorbs and desorbs evaporated fuel in the adsorption chamber, and a microcapsule-type heat storage material in which a phase change material that absorbs and releases latent heat in response to temperature changes is enclosed in a synthetic resin outer shell. In a canister having a tank port communicating with a fuel tank and an air port communicating with the atmosphere,
In the adsorption chamber, two types of heat storage materials having different alcohol resistance are accommodated in the tank port side and the atmospheric port side,
A canister in which a heat storage material having higher alcohol resistance than a heat storage material stored in the atmospheric port side portion is stored in a tank port side portion in the adsorption chamber.   The canister according to claim 1, wherein the outer shell of the heat storage material accommodated in the tank port side portion is made of a synthetic resin having higher alcohol resistance than the outer shell of the heat storage material accommodated in the atmosphere port side portion. The outer shell of the heat storage material housed in the tank port side portion and the outer shell of the heat storage material housed in the atmosphere port side portion are made of the same synthetic resin,
The canister according to claim 1, wherein the outer shell of the heat storage material accommodated in the tank port side portion is covered with a synthetic resin having high alcohol resistance.   The canister according to any one of claims 1 to 3, wherein the heat storage material having high alcohol resistance is accommodated in a range of 20% from a tank port side to 70% of a tank port side in the adsorption chamber.   The canister according to any one of claims 1 to 4, wherein the two kinds of heat storage materials are formed by granulating a plurality of microcapsules with a binder.   The canister according to any one of claims 1 to 4, wherein the two kinds of heat storage materials are formed by granulating a plurality of microcapsules together with a powdery adsorbent with a binder.   The canister according to any one of claims 1 to 6, wherein the canister is used for adsorbing and desorbing an evaporative mixed fuel produced from a fuel mixed with alcohol. The adsorption chamber in the hollow cylindrical canister case is filled with an adsorbent that adsorbs and desorbs evaporative fuel, and a phase change material that absorbs and releases latent heat according to temperature changes in the outer shell made of synthetic resin. A canister manufacturing method comprising: a tank port in which a microcapsule-type heat storage material is accommodated and communicating with a fuel tank; and an atmospheric port communicating with the atmosphere provided at a position opposite to the tank port,
Filling the canister case with the adsorbent and two kinds of heat storage materials having different specific gravity and alcohol resistance; and
A step of applying vibration to the canister case in a state where the atmospheric port and the tank port are in a vertical direction;
A method for producing a canister, comprising:

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