JP5921987B2 - Evaporative fuel processing equipment - Google Patents

Description

  The present invention relates to a fuel vapor processing apparatus.

  2. Description of the Related Art Conventionally, an evaporative fuel treatment device (hereinafter also referred to as a canister) that temporarily adsorbs fuel components in evaporative fuel with activated carbon in order to prevent the evaporative fuel from an automobile fuel tank or the like from being released into the atmosphere. It is used.

  Such a canister has a case in which a tank port, a purge port, and an atmospheric port are formed, and a plurality of adsorption layers filled with activated carbon are formed in the case, and the activated carbon constituting the adsorption layer located closest to the tank port side It is known that two types of activated carbons having different particle diameters are used as the activated carbon filled in the canister. Patent Document 1).

JP 2004-225550 A

  The smaller the particle size of activated carbon, the more the fuel component is adsorbed, but the remaining amount of fuel component after purging also increases. In the prior art canister, since only two types of activated carbon are used, the concentration difference of the fuel component remaining in the adsorption layer is large between the adsorption layers having different particle sizes, and the diffusion of the fuel component is likely to occur. Become.

  Further, since the conventional canister has only a filter provided between the adsorption layers, the separation distance between the adsorption layers is short, and the fuel component is likely to diffuse between the adsorption layers.

  Therefore, the fuel component is likely to diffuse to the atmosphere port side, and there is a risk that the fuel component will be blown into the atmosphere.

  Therefore, an object of the present invention is to provide an evaporative fuel processing device that reduces the blow-by of evaporative fuel components from the atmospheric port to the outside as compared with the conventional canister.

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a passage through which a fluid can flow is formed, a tank port and a purge port are formed at one end side of the passage, and the other end side of the passage. Is formed with an atmospheric port, the passage is filled with a granular adsorbent capable of adsorbing the evaporated fuel component , and three or more adsorbing layers arranged in series are separated from the adsorbing layers adjacent to each other. Having a spacing portion;
The pressure loss per unit volume of the adsorbent filled in each adsorption layer is the largest at the adsorption layer located on the most tank port side, the smallest at the adsorption layer located on the most atmospheric port side,
Between the adsorption layer located closest to the tank port and the adsorption layer located closest to the atmospheric port, the pressure loss per unit volume of the filled adsorbent is smaller than that of the adsorption layer located closest to the tank port. Provide an adsorption layer that is larger than the adsorption layer located on the most atmospheric port side,
The pressure loss per unit volume of the adsorbent in the adsorbing layer adjacent to the atmosphere port side is not increased ,
The volume of the separation portion located closest to the atmosphere port is larger than the volume of the adsorption layer located closest to the atmosphere port .

  According to a second aspect of the present invention, in the first aspect of the invention, the pressure loss per unit volume of the adsorbent filled in each adsorption layer is located on the atmosphere port side from the adsorption layer located on the tank port side. It is characterized by being made smaller in steps toward the adsorption layer.

The invention according to claim 3 is the invention according to claim 1, wherein the average particle diameter of the adsorbent filled in each adsorption layer is the smallest in the adsorption layer located closest to the tank port, and is located closest to the atmosphere port. The largest adsorbing layer,
The average particle size of the adsorbent filled between the adsorption layer located closest to the tank port and the adsorption layer located closest to the atmospheric port is larger than that of the adsorption layer located closest to the tank port, and is the most atmospheric port. Provide an adsorption layer smaller than the adsorption layer located on the side,
The average particle size of the adsorbent in adjacent adsorbing layers is such that the air port side does not become small .

  The invention according to claim 4 is the invention according to claim 3, wherein the average particle size of the adsorbent filled in each adsorption layer is changed from the adsorption layer located on the tank port side to the adsorption layer located on the atmosphere port side. It is characterized by increasing in steps.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein, in the evaporative fuel processing device, the adsorption layer provided closest to the tank port is made of crushed coal. It is characterized by.

  According to the present invention, the pressure loss per unit volume of the adsorbent filled in each adsorption layer is the largest in the adsorption layer located on the most tank port side and the smallest in the adsorption layer located on the most atmospheric port side. The pressure loss per unit volume of the adsorbent packed between the adsorption layer located closest to the tank port and the adsorption layer located closest to the atmospheric port is smaller than that of the adsorption layer located closest to the tank port. By providing an adsorption layer that is larger than the adsorption layer located closest to the atmospheric port side, the pressure loss per unit volume of the adsorbent in the adjacent adsorption layer is the same, or by reducing the atmospheric port side, The difference in the residual concentration of the fuel component between the adsorption layers after purging can be made smaller than that of the conventional canister.

  Further, by providing a separation portion that separates the adsorbing layers adjacent to each other, the diffusion of the fuel components between the adsorbing layers adjacent to each other can be suppressed lower than the conventional canister, and the fuel components can be diffused to the atmosphere port side. Therefore, it is possible to reduce the blow-through of the fuel component to the atmosphere.

Schematic for demonstrating the evaporative fuel processing apparatus which concerns on Example 1 of this invention. Schematic for demonstrating the evaporative fuel processing apparatus which concerns on Example 2 of this invention.

An embodiment for carrying out the present invention will be described with reference to the drawings.
[Example 1]
FIG. 1 shows a first embodiment of the present invention.

  As shown in FIG. 1, the fuel vapor processing apparatus 1 according to the present invention has a case 2, and a passage 3 through which a fluid can flow is formed inside the case 2, and one end side end of the passage 3 in the case 2. A tank port 4 and a purge port 5 are formed at the part, and an atmospheric port 6 is formed at the other end.

  In the passage 3, three adsorption layers filled with an adsorbent capable of adsorbing the evaporated fuel component, that is, the first adsorption layer 11, the second adsorption layer 12, and the third adsorption layer 13 are arranged in series. . In this example, activated carbon was used as the adsorbent.

  As shown in FIG. 1, a main chamber 21 communicating with the tank port 4 and the purge port 5 and a sub chamber 22 communicating with the atmospheric port 6 are formed in the case 2, and the main chamber 21 and the sub chamber 22 are formed. Is communicated by a space 23 formed in the case 2 on the side opposite to the atmosphere port 6 side, and when the fluid flows in the passage 3, it is folded back in the space 23 and flows in a substantially U-shape. .

  The tank port 4 communicates with an upper air chamber of a fuel tank (not shown), and the purge port 5 is connected to an intake passage of the engine via a purge control valve (VSV) (not shown). The opening degree of the purge control valve is controlled by an electronic control unit (ECU), and purge control is performed based on measured values of an A / F sensor or the like during engine operation. The atmospheric port 6 communicates with the outside through a passage (not shown).

  The first adsorption layer 11 is formed in the main chamber 21 by filling the adsorbent activated carbon 11a with a predetermined density. As the activated carbon 11a, granulated coal or crushed coal can be used, but crushed coal was used in this example. In addition, in the figure, in order to make it easy to understand that the first adsorption layer 11 is composed of activated carbon, it is described with granulated coal.

  Between the tank port 4 and the purge port 5 in the case 2, a baffle plate 15 that extends from the inner surface of the case 2 to a part of the first adsorption layer 11 is provided. The baffle plate 15 allows fluid flowing between the tank port 4 and the purge port 5 to flow through the first adsorption layer 11.

  The first adsorption layer 11 is covered with a filter 16 made of a nonwoven fabric or the like on the tank port 4 side, and a filter 17 made of a nonwoven fabric or the like on the purge port 5 side. Further, a filter 18 made of urethane or the like covering the entire surface is provided on the side surface of the space 23 of the first adsorption layer 11, and a plate 19 having a large number of communication holes is provided below the filter 18. . The plate 19 is biased toward the tank port 4 by a biasing means 20 such as a spring.

  The second adsorption layer 12 is formed on the space 23 side in the sub chamber 22 by filling the activated carbon 12a as the adsorbent with a predetermined density. As this activated carbon 12a, granulated charcoal or crushed charcoal can be used, but granulated charcoal was used in this example.

  A filter 26 made of urethane or the like is provided on the space 23 side of the second adsorption layer 12 to cover the whole. On the space 23 side of the filter 26, there is provided a plate 27 provided with a large number of communication holes on the entire surface. The plate 27 is biased toward the atmosphere port 6 by a biasing member 28 such as a spring.

  The space 23 is formed between the plates 19 and 27 and the cover plate 30 of the case 2, and the first adsorption layer 11 and the second adsorption layer 12 are communicated with each other through the space 23. The space 23 constitutes a separation portion that separates the first adsorption layer 11 and the second adsorption layer 12.

  Activated carbon 13a as the adsorbent is filled at a predetermined density on the atmosphere port 6 side in the sub chamber 22 to form a third adsorption layer 13. As this activated carbon 13a, granulated charcoal or crushed charcoal can be used, but in this example, granulated charcoal was used. On the atmosphere port side of the third adsorption layer 13, a filter 33 made of a nonwoven fabric or the like covering the whole is provided.

  A separation portion 31 that separates the adsorption layers 12 and 13 from each other by a predetermined distance is provided between the end surface on the atmosphere port 6 side of the second adsorption layer 12 and the end surface on the space 23 side of the third adsorption layer 13. . The volume of the separation portion 31 is set larger than the volumes of the second adsorption layer 12 and the third adsorption layer 13.

  Filters 35 and 36 made of urethane or the like are provided at the end of the separating portion 31 on the second adsorbing layer 12 side and the end of the third adsorbing layer 13 side. A space forming member 37 that can separate the filters 35 and 36 by a predetermined distance is provided between the filters 35 and 36. At the end portions of the space forming member 37 on both the adsorption layers 12 and 13 side, throttle portions 37a and 37b for reducing the passage sectional area of the passage 3 are provided. As the throttle portions 37a and 37b, for example, a member in which a plurality of communication holes are formed in a partition member orthogonal to the flow path direction of the passage 3 can be used.

  No adsorbent is provided in the spacing portion 31. The separating portions 31 and 32 may be formed only by a filter such as urethane, or may be configured only by the space forming member 37, as long as adjacent adsorbing layers can be separated from each other by a predetermined distance.

  Next, the activated carbons 11a, 12a, and 13a that are adsorbents constituting the adsorption layers 11, 12, and 13 will be described.

  The average particle diameter of the activated carbon 13 a that is the adsorbent constituting the third adsorption layer 13 is set larger than the average particle diameter of the activated carbon 12 a that is the adsorbent constituting the second adsorption layer 12. Further, the average particle diameter of the activated carbon 12 a that is the adsorbent constituting the second adsorption layer 12 is set larger than the average particle diameter of the activated carbon 11 a that is the adsorbent constituting the first adsorption layer 11.

  That is, the average particle diameters of the activated carbons 11a, 12a, and 13a filled in the adsorption layers 11, 12, and 13 are stepped from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6. It is getting bigger.

  Thereby, the pressure loss per unit volume of the adsorbent 13a filled in the third adsorbing layer 13 is smaller than the pressure loss per unit volume of the adsorbent 12a filled in the second adsorbing layer 12. Further, the pressure loss per unit volume of the adsorbent 12a filled in the second adsorption layer 12 is smaller than the pressure loss per unit volume of the adsorbent 11a filled in the first adsorption layer 11.

  That is, the pressure loss per unit volume of the activated carbon 11a, 12a, 13a filled in each of the adsorption layers 11, 12, 13 is directed from the adsorption layer located on the tank port 4 side to the adsorption layer located on the atmospheric port 6. And become smaller step by step.

  With the above-described configuration, the fluid containing the evaporated fuel that has flowed into the evaporated fuel processing apparatus 1 from the tank port 4 is adsorbed by the adsorbent in each of the adsorbing layers 11 to 13, and then the atmosphere from the atmospheric port 6 Is released.

  On the other hand, during the purge control during engine operation, the purge control valve is opened by the electronic control unit (ECU), and the air sucked into the evaporated fuel processing apparatus 1 from the atmospheric port by the negative pressure in the intake passage is Flows in the reverse direction and is supplied from the purge port 5 to the intake passage of the engine. At that time, the fuel component adsorbed by the adsorbent in each of the adsorption layers 11 to 13 is desorbed and supplied to the engine together with air.

  The evaporative fuel processing apparatus 1 of the present invention has the following structure and configuration, and thus provides the following operations and effects.

  As the particle size of activated carbon increases, the amount of adsorption of the fuel component of the evaporated fuel decreases and the remaining amount after purging also decreases. In the present invention, the average particle diameter of the activated carbons 11a, 12a, and 13a filled in the adsorption layers 11, 12, and 13 is changed from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6. By increasing in steps, the remaining amount of the fuel component after purging the third adsorption layer 13 located closest to the atmosphere port 6 can be suppressed lower than the other adsorption layers 11 and 12.

  Further, by providing three adsorbing layers and gradually decreasing the average particle size of the activated carbon composing the adsorbing layer from the atmospheric port 6 toward the tank port side, the remaining amount of fuel components after purging is reduced. The difference in concentration of the remaining fuel component between the adsorbing layers can be made smaller than the conventional canister by increasing the air port 6 gradually from the atmospheric port 6 to the tank port side. Thereby, the diffusion of the fuel component between the adsorbing layers adjacent to each other can be suppressed as compared with the conventional canister.

  In addition, a separation portion 31 having a volume larger than the volumes of the second adsorption layer 12 and the third adsorption layer 13 is provided between the second adsorption layer 12 and the third adsorption layer 13, and the first adsorption layer 11 and the second adsorption layer. 12 is provided with a folded space 23. The spacing portion 31 and the space 23 are sufficient to suppress the diffusion of the fuel component between the adjacent adsorption layers, and the diffusion of the fuel component between the adjacent adsorption layers can be suppressed to a lower level.

  In addition, since the pressure loss per unit volume of the adsorbent filled in the adsorption layer is increased toward the tank port 4 side, the residence time of the evaporated fuel is longer toward the tank port 4 side and shorter toward the atmosphere port 6 side. As a result, the remaining amount of the fuel component after purging the third adsorption layer 13 located closest to the atmosphere port 6 can be kept lower than the other adsorption layers 11 and 12.

  As described above, the remaining amount of the fuel component after the purge of the third adsorption layer 13 located closest to the atmosphere port 6 side can be suppressed low, and the diffusion of the fuel component to the atmosphere port 6 side can be suppressed. This makes it possible to keep the fuel component from being blown into the atmosphere lower than that of the canister.

[Example 2]
In the first embodiment, the three adsorbing layers 11, 12, and 13 are provided in the case 2. However, the number of adsorbing layers can be set to an arbitrary number as long as the number is three or more. The average particle diameter of the activated carbon filled in each adsorption layer is gradually increased from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6, and the activated carbon filled in each adsorption layer. The pressure loss per unit volume is set so as to decrease stepwise from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6.

  For example, as shown in FIG. 2, it is good also as the evaporative fuel processing apparatus 41 which provided the four adsorption layers 11, 12, 13, and 14 in series in the channel | path 3. As shown in FIG.

  As shown in FIG. 2, the evaporative fuel processing device 41 includes a second adsorbing layer 12, a third adsorbing layer 13, and a fourth adsorbing layer 12 that are formed by filling the sub chamber 22 with activated carbon 12 a, 13 a, and 14 a that are adsorbents. Three adsorption layers of the adsorption layer 14 were provided.

  A separation portion 31 that separates the adsorption layers 12 and 13 from each other by a predetermined distance is provided between the end surface on the atmosphere port 6 side of the second adsorption layer 12 and the end surface on the space 23 side of the third adsorption layer 13. . The volume of the separation portion 31 is set larger than the volumes of the second adsorption layer 12 and the third adsorption layer 13.

  A separation portion 32 that separates the adsorption layers 13 and 14 from each other by a predetermined distance is provided between the end surface of the third adsorption layer 13 on the atmosphere port 6 side and the end surface of the fourth adsorption layer 14 on the space 23 side. . The volume of the separation portion 32 is set larger than the volumes of the third adsorption layer 13 and the fourth adsorption layer 14.

  The average particle diameter of the activated carbon 14 a that is the adsorbent constituting the fourth adsorption layer 14 is set larger than the average particle diameter of the activated carbon 13 a that is the adsorbent constituting the third adsorption layer 13. Further, the average particle diameter of the activated carbon 13 a that is the adsorbent constituting the third adsorption layer 13 is set larger than the average particle diameter of the activated carbon 12 a that is the adsorbent constituting the second adsorption layer 12. Further, the average particle diameter of the activated carbon 12 a that is the adsorbent constituting the second adsorption layer 12 is set larger than the average particle diameter of the activated carbon 11 a that is the adsorbent constituting the first adsorption layer 11.

  That is, the average particle diameter of the activated carbon 11a, 12a, 13a, 14a filled in each of the adsorption layers 11, 12, 13, 14 is changed from the adsorption layer located on the tank port 4 side to the adsorption layer located on the atmospheric port 6. It is getting bigger step by step.

  Thereby, the pressure loss per unit volume of the activated carbon 11a, 12a, 13a, 14a filled in each of the adsorption layers 11, 12, 13, 14 is located in the atmospheric port 6 from the adsorption layer located on the tank port 4 side. It becomes smaller in steps toward the adsorption layer.

Since the other members are the same as those in the first embodiment, the same reference numerals as those described above are used and the description thereof is omitted.
Also in the second embodiment, the same operations and effects as in the first embodiment are achieved.

[Example 3]
In Examples 1 and 2, the average particle size of the activated carbon filled in each adsorption layer is increased stepwise from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6. The pressure loss per unit volume of the activated carbon filled in each adsorption layer was set to decrease stepwise from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmospheric port 6. The average particle size of the activated carbon that is the adsorbent filled in each adsorption layer is the smallest in the adsorption layer located on the tank port 4 side, the largest in the adsorption layer located on the atmosphere port 6 side, and the largest in the tank The average particle size of the adsorbent filled between the adsorption layer located on the port 4 side and the adsorption layer located closest to the atmospheric port 6 is larger than that of the adsorption layer located closest to the tank port 4 side, and the most atmospheric Located on port 6 side That the adsorption layer becomes smaller than the adsorption layer is provided, the average particle size of the adsorbent in the adsorption layer thereof adjacent the same or, may be atmospheric port 5 side becomes larger.

  For example, as shown in FIG. 2, in the evaporative fuel processing apparatus 41 having four adsorption layers, the average particle diameters of the activated carbons 13a and 14a constituting the third adsorption layer 13 and the fourth adsorption layer 14 are set to be the same. You may comprise the average particle diameter of activated carbon 11a, 12a, 13a, 14a which comprises the adsorption layers 11, 12, 13, and 14 by three different average particle diameters.

  Further, in the evaporative fuel processing apparatus 41 having four adsorption layers as shown in FIG. 2, the average particle diameters of the activated carbons 12a and 13a constituting the second adsorption layer 12 and the third adsorption layer 13 are set to be the same. You may comprise the average particle diameter of activated carbon 11a, 12a, 13a, 14a which comprises the adsorption layers 11, 12, 13, and 14 by three different average particle diameters.

Since other members are the same as those in the first and second embodiments, description thereof is omitted.
In the third embodiment, the same operations and effects as the first and second embodiments are achieved.

[Example 4]
In Examples 1 to 3, in order to change the pressure loss per unit volume of the activated carbon filled in each adsorption layer, the average particle size of the activated carbon as the adsorbent was changed. By changing the pressure loss per unit volume of the activated carbon filled in the adsorption layer, the pressure loss per unit volume of the adsorbent filled in each adsorption layer is the highest in the adsorption layer located on the tank port 4 side. The unit volume of the adsorbent packed between the adsorption layer located closest to the tank port 4 and the adsorption layer located closest to the atmosphere port 6 is the largest and the adsorption layer located closest to the atmosphere port 6 is the smallest. A unit volume of the adsorbent in adjacent adsorbing layers is provided in which an adsorbing layer in which the pressure loss per hit is smaller than the adsorbing layer located closest to the tank port 4 and greater than the adsorbing layer located closest to the air port 6 Hit The pressure loss, same or may be atmospheric air port side is reduced.

  Further, preferably, the pressure loss per unit volume of the adsorbent filled in each adsorption layer is gradually reduced from the adsorption layer located on the tank port 4 side toward the adsorption layer located on the atmosphere port 6 side. It may be made to become.

  For example, the pressure loss per unit volume of the activated carbon filled in each adsorption layer can be changed by changing the shape of the activated carbon and changing the space ratio in each adsorption layer.

Since other members are the same as those in the first to third embodiments, description thereof is omitted.
Moreover, also in this Example 3, there exists an effect | action and effect similar to the said Examples 1-3.

[Other Examples]
If activated carbon, which is an adsorbent that has three or more adsorbing layers and constitutes each adsorbing layer, satisfies the same relationship as in Examples 1 to 4, the shape of the entire evaporated fuel processing apparatus, the adsorbing layer, The number and shape of the spacing portions, spaces, etc., the arrangement, etc. can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1,41 Evaporative fuel processing apparatus 3 Passage 4 Tank port 5 Purge port 6 Atmospheric port 11, 12, 13, 14 Adsorption layer 23, 31, 32 Separation part

Claims (5)

A passage through which fluid can flow is formed, a tank port and a purge port are formed on one end side of the passage, an air port is formed on the other end side of the passage, and an evaporated fuel component is formed in the passage. 3 or more adsorbing layers arranged in series with a granular adsorbent that can adsorb the adsorbing material , and a separating portion that separates the adsorbing layers adjacent to each other,
The pressure loss per unit volume of the adsorbent filled in each adsorption layer is the largest at the adsorption layer located on the most tank port side, the smallest at the adsorption layer located on the most atmospheric port side,
Between the adsorption layer located closest to the tank port and the adsorption layer located closest to the atmospheric port, the pressure loss per unit volume of the filled adsorbent is smaller than that of the adsorption layer located closest to the tank port. Provide an adsorption layer that is larger than the adsorption layer located on the most atmospheric port side,
The pressure loss per unit volume of the adsorbent in the adsorbing layer adjacent to the atmosphere port side is not increased ,
An evaporative fuel processing apparatus characterized in that the volume of the separation portion located closest to the atmosphere port is larger than the volume of the adsorption layer located closest to the atmosphere port .   The pressure loss per unit volume of the adsorbent filled in each adsorption layer is reduced stepwise from the adsorption layer located on the tank port side toward the adsorption layer located on the atmosphere port side. Item 2. The fuel vapor processing apparatus according to Item 1. The average particle size of the adsorbent filled in each adsorption layer is the smallest at the adsorption layer located closest to the tank port, the largest at the adsorption layer located closest to the atmosphere port,
The average particle size of the adsorbent filled between the adsorption layer located closest to the tank port and the adsorption layer located closest to the atmospheric port is larger than that of the adsorption layer located closest to the tank port, and is the most atmospheric port. Provide an adsorption layer smaller than the adsorption layer located on the side,
2. The evaporative fuel processing apparatus according to claim 1, wherein an average particle size of the adsorbent in adjacent adsorbing layers is not reduced on the air port side .   The average particle diameter of the adsorbent filled in each adsorption layer is increased stepwise from the adsorption layer located on the tank port side toward the adsorption layer located on the atmosphere port side. Evaporative fuel processing equipment.   5. The evaporative fuel processing apparatus according to claim 1, wherein the adsorption layer provided closest to the tank port side is made of crushed coal.

Images