JP5179965B2 - Canister - Google Patents

Description

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

  Conventionally, while the internal combustion engine is stopped, fuel vapor generated from the fuel tank is introduced into the canister and adsorbed by the adsorbent, and the adsorbed fuel is desorbed by the intake pipe negative pressure during operation of the internal combustion engine. Combustion is performed in the combustion chamber.

In such a canister, when the internal combustion engine is stopped, the fuel vapor flowing in from the fuel tank may not be completely adsorbed and may be discharged into the atmosphere from the introduction port for introducing air. In order to prevent this, as described in Patent Document 1, the adsorbent of the adsorbent layer on the inlet port side has a smaller adsorbed amount of evaporated fuel than the adsorbent of the adsorbent layer on the inlet port side, and holds the evaporated fuel. An active carbon filled with activated carbon having a characteristic that suppresses blow-through has been proposed.
JP 2006-83871 A

  However, in such a conventional one, the adsorbent of the adsorbent layer on the introduction port side has a characteristic that the adsorbed amount of the evaporated fuel is smaller than the adsorbent of the adsorbent layer on the inflow port side and has a large holding power of the evaporated fuel. When the internal combustion engine is desorbed during operation, the fuel is likely to remain in the state of being held by the adsorbent on the introduction port side, and the remaining fuel is released from the introduction port to the outside due to external temperature changes, etc. There was a problem that it might end.

  An object of the present invention is to provide a canister that recovers an adsorbent in a short time and suppresses the release of fuel.

In order to achieve the above object, the present invention provides an inflow port for introducing fuel vapor from a fuel tank and an outflow port for discharging desorbed fuel to an intake pipe of an internal combustion engine while partitioning the inside of the container into a plurality of chambers. a main chamber provided with fuel by connecting the chambers between the sub-chamber provided with inlet port for introducing air into the series was filled with the adsorbent to the chambers, was introduced through the inlet port The present invention relates to a canister that adsorbs vapor to the adsorbent and desorbs fuel adsorbed on the adsorbent by air introduced through the introduction port.
In the canister of the present invention, the sub chamber is smaller in volume than the main chamber, and the first sub chamber connected in series to the main chamber and the introduction port connected in series to the first sub chamber are provided. is divided into a second sub-chamber, the adsorbent filling to the each chamber, molded from the granular activated carbon, a plurality of pellets, and, the second sub-chamber of the pellet, a number of air passage Is formed inside, the air passage is not formed in the pellets of the main chamber and the first sub chamber, and the pellets of the second sub chamber are formed in the main chamber and the first sub chamber. The amount of desorption per unit time when fuel is desorbed from the adsorbent is large. Said second sub-chamber is equivalent to the cross-sectional area of the cross-sectional area smaller than the cross-sectional area of the first sub-chamber, the second sub-length of the chamber the adsorbent layer filled in L and the second sub-chamber The ratio L / D with the diameter D of the circular area is 1 or more.
At least one of the pellets in the second subchamber has a plurality of air passages that reach the inside from the surface of the pellet, and the plurality of air passages communicate with each other inside the pellet.

Or before Symbol structure filled with the main chamber and the adsorbent heat capacity is larger than said second sub-chamber to the first sub-chamber.

  In the canister of the present invention, the adsorbent filled in the chamber provided with the introduction port is a pellet formed from granular activated carbon, and the pellet per unit time when the fuel is desorbed from the adsorbent in the other chamber. Therefore, the adsorbent in the chamber provided with the introduction port can be recovered in a short time, and the release of the fuel remaining in the adsorbent can be suppressed.

  Moreover, since the ratio L / D of the length L to the diameter D is 1 or more in the chamber provided with the introduction port, the fuel vapor is efficiently adsorbed and the blow-through can be suppressed. Furthermore, by forming a large number of air passages in the pellet, it is possible to easily increase the amount of desorption per unit time when the fuel is desorbed. By filling the first sub-chamber with an adsorbent having a larger heat capacity than the other chambers, the temperature drop is suppressed and the desorption of fuel from the adsorbent is promoted.

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

  As shown in FIG. 3, an inflow port 16 connected to the fuel tank 12 via a check valve 14 is formed in the container 1 on the side opposite to the lid member 2. The inflow port 16 is connected to the main chamber 6 so that fuel vapor from the fuel tank 12 can be introduced.

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

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

  The main chamber 6 is filled with an adsorbent 42 between both the filters 28 and 30 on the inflow port 16 and outflow port 18 side and the filter 32 on the lid member 2 side. In this embodiment, the adsorbent 42 is a pellet formed by kneading granular activated carbon together with a binder into a cylindrical shape having a diameter of about 1 to 3 mm and a length of about 3 to 10 mm. In addition, not only when the main chamber 6 is filled with pellets, the granular activated carbon may be filled into the main chamber 6 as it is.

  On the other hand, a porous plate 44 is inserted into the sub chamber 8, and the sub chamber 8 is divided into a first sub chamber 8 a connected to the communication path 10 and a second sub chamber 8 b connected to the introduction port 26. ing. A plurality of chambers, in the present embodiment, a main chamber 6, a first sub chamber 8a, and a second sub chamber 8b are provided in the container 1, and the main chamber 6 and the first sub chamber 8a are connected by a communication passage 10. In addition, the first sub chamber 8a and the second sub chamber 8b are formed in communication. Accordingly, the main chamber 6, the first sub chamber 8a, and the second sub chamber 8b are connected in series.

  Filters 46 and 48 are provided on both sides of the perforated plate 44, respectively. Between the filters 36 and 46 in the first sub chamber 8a, the adsorbent 42 of the main chamber 6 and the second sub chamber 8b are provided. An adsorbent 50 having a larger heat capacity than the adsorbent 54 described later is filled. In the present embodiment, the adsorbent 50 is a pellet having a diameter of about 1 to 3 mm and a length of about 3 to 10 mm. By filling the first sub chamber 8a with the adsorbent 50 having a large heat capacity, the amount of fuel adsorbed can be increased, and the burden on the adsorbent 54 described later in the second sub chamber 8b can be reduced. Moreover, ventilation resistance can be reduced by using a pellet. When the heat capacity of the adsorbent 42 in the main chamber 6 is increased, the amount of fuel adsorbed by the adsorbent 42 in the main chamber 6 is excessively increased, and the blow-by property is deteriorated. The adsorbent 50 having a large heat capacity may be filled into the first sub chamber 8a as necessary, and only the same pellets as the main chamber 6 may be filled into the first sub chamber 8a.

  An adsorbent 54 is filled between the filters 34 and 48 in the second sub chamber 8b. The adsorbent 54 is formed by activating granular activated carbon, mixing an additive together with a binder to form a pellet, and then removing the additive. As shown in FIG. 2, the pellet-shaped adsorbent 54 formed in this way has a large number of air passages 56 formed in the adsorbent 54 after the additive is removed. The air passage 56 is a hole having a diameter of about 0.05 mm and is formed in a large number from the surface of the adsorbent 54 to the inside of the adsorbent 54, and the air passages 56 communicate with each other inside the adsorbent 54. is there.

  The air passage 56 facilitates the penetration of air into the adsorbent 54, and the fuel is desorbed from the adsorbent 42 in the main chamber 6 and the adsorbent 50 in the first sub chamber 8 a that do not form the air passage 56. The amount of desorption per unit time is large. For example, when the same amount of air is supplied to the adsorbents 42, 50, and 54 adsorbed with the same amount of fuel per unit weight for the same amount of time and the separation of the amount of fuel is compared, the air passage 56 is provided. The amount of desorption from the formed adsorbent 54 per unit time is large.

  The adsorbents 42, 50, 54 may be formed into pellets using the same activated carbon. At that time, the adsorbent 54 formed with the air passage 56 reduces the amount of fuel that can be adsorbed. Desorption rate is fast.

  The second sub chamber 8b is formed so that its cross-sectional area is smaller than the cross-sectional area of the first sub chamber 8a. The length L between the filters 34 and 48 of the second sub chamber 8b (the length of the filled adsorbent 54 layer) and the diameter when the cross section of the second sub chamber 8b is converted to a circular cross section. The ratio L / D with D is 1 or more. When L / D is 1 or more, the fuel vapor is efficiently adsorbed in the second sub chamber 8b, and the amount of fuel vapor released from the introduction port 26 into the atmosphere can be reduced.

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

  When the fuel vapor is introduced into the main chamber 6, it is adsorbed by the adsorbent 42 on the inflow port 16 side, and the fuel vapor is sequentially adsorbed toward the adsorbent 42 on the lid member 2 side. The fuel vapor that could not be adsorbed by the adsorbent 42 in the main chamber 6 passes through the communication path 10 and is introduced into the first sub chamber 8b. Then, it is adsorbed by the adsorbent 50 in the first sub chamber 8a. At that time, since the first sub chamber 8a is filled with the adsorbent 50 having a larger heat capacity than the other chambers 6 and 8b, the heat due to the liquefaction of the fuel vapor is deprived of heat by the endothermic of the adsorbent 50, Temperature rise is suppressed. Therefore, adsorption to the adsorbent 50 is promoted.

  Further, the fuel vapor that has not been adsorbed in the first sub chamber 8a passes through the filter 46, the porous plate 44, and the filter 48 and is introduced into the second sub chamber 8b. And it is adsorbed by the adsorbent 54 in the second sub chamber 8b. The air adsorbed and separated by the fuel is discharged from the introduction port 26 into the atmosphere. The second subchamber 8b is formed such that the ratio L / D between the length L and the diameter D is 1 or more, so that the fuel vapor is efficiently adsorbed and the amount of fuel vapor released from the introduction port 26 into the atmosphere is reduced. Can be reduced.

  On the other hand, during operation of the internal combustion engine 20, air in the atmosphere is introduced from the introduction port 26 into the second sub chamber 8 b through the filter 34. The air introduced into the second sub chamber 8b, after desorbing the fuel from the adsorbent 54 in the second sub chamber 8b, passes through the filter 48, the perforated plate 44, and the filter 46 and is guided to the first sub chamber 8a. It is written.

  Since a large number of air passages 56 are formed in the adsorbent 54 in the second sub chamber 8b, the amount of desorption per unit time when the fuel is desorbed is large, and the adsorbent in the second sub chamber 8b. From 54, the adsorbed fuel is quickly desorbed, and the fuel vapor can be adsorbed quickly. In addition, since the air passage 56 is formed up to the inside of the pellet-shaped adsorbent 54, the fuel inside the adsorbent 54 is also quickly desorbed.

  The air containing the fuel vapor is introduced into the first sub chamber 8a, and the fuel is also desorbed from the adsorbent 50 in the first sub chamber 8a. At that time, the heat of vaporization is deprived and the temperature is lowered. However, since the first sub chamber 8a is filled with the adsorbent 50 having a larger heat capacity than the other chambers 6 and 8b, the temperature drop is suppressed and the adsorption is suppressed. Desorption of fuel from the material 50 is promoted. Therefore, the canister can be downsized, and the temperature change of the adsorbent 50 can be sufficiently suppressed even if the canister is downsized.

  Further, the air containing the fuel vapor is guided from the first sub chamber 8 a to the main chamber 6 through the communication path 10. Similarly, fuel is desorbed from the adsorbent 42 in the main chamber 6. It is discharged to the intake pipe 22 through the main chamber 6, the outflow port 18, and the purge valve 24, and burned in the internal combustion engine 20.

  Thus, when air is introduced from the introduction port 26, the fuel is quickly desorbed from the adsorbent 54 in the second sub chamber 8b, and the adsorption of the second sub chamber 8b is quickly recovered. Therefore, when desorbing during operation of the internal combustion engine, the amount of fuel remaining in the state held by the adsorbent 54 is very small, and the remaining fuel is discharged from the introduction port 26 when the internal combustion engine is stopped due to an external temperature change or the like. It can suppress discharge | released outside. For example, even when the operation and stop of the internal combustion engine 20 are frequently repeated, the adsorption of the second sub chamber 8b is quickly recovered, and the fuel vapor is adsorbed in the main chamber 6 while the operation is stopped. Even if not, it is reliably adsorbed in the second sub chamber 8b and the fuel vapor to the atmosphere is prevented from being discharged. Therefore, the collection performance can be improved. In the present embodiment, the first sub chamber 8a is provided. However, the entire sub chamber 8 may be the second sub chamber 8b filled with the adsorbent 54 without providing the first sub chamber 8a.

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

It is sectional drawing of the canister as one Embodiment of this invention. It is the elements on larger scale of the adsorbent of this embodiment. It is explanatory drawing which shows the connection of the canister of this embodiment, a fuel tank, and an internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Lid member 4 ... Partition 6 ... Main chamber 8 ... Sub chamber 8a ... 1st sub chamber 8b ... Sub chamber 10 ... Communication path 12 ... Fuel tank 16 ... Inflow port 18 ... Outflow port 20 ... Internal combustion engine 22 ... Intake pipe 26 ... Introducing ports 28, 30, 32, 34, 36, 46, 48 ... Filters 42, 50, 54 ... Adsorbent 56 ... Ventilation path

Claims (2)

A main chamber provided with an inflow port for introducing the fuel vapor from the fuel tank and an outflow port for discharging the desorbed fuel to the intake pipe of the internal combustion engine, and an introduction port for introducing air while partitioning the container into a plurality of chambers filled with adsorbent the chambers to be connected in series to the chambers between the sub-chamber provided with, together with the adsorbing fuel vapor introduced through the inlet port into the adsorbent, the inlet port In the canister for desorbing the fuel adsorbed on the adsorbent by the air introduced through
The sub chamber is smaller in volume than the main chamber, and is connected to the main chamber in series. The second sub chamber is connected in series to the first sub chamber and provided with the introduction port. Divided into
The adsorbent filling to the each chamber, molded from the granular activated carbon, a plurality of pellets, and, the second sub-chamber of the pellet, whereas a large number of air passage formed therein, the The pellets in the main chamber and the first sub chamber have no air passage, and the pellets in the second sub chamber are obtained when fuel is desorbed from the adsorbent in the main chamber and the first sub chamber. Large amount of desorption per unit time
Said second sub-chamber is equivalent to the cross-sectional area of the cross-sectional area smaller than the cross-sectional area of the first sub-chamber, the second sub-length of the chamber the adsorbent layer filled in L and the second sub-chamber The ratio L / D with the diameter D of the circular area to be is 1 or more,
At least one of the pellets in the second subchamber has a plurality of air passages that reach the inside from the surface of the pellet, and the plurality of air passages communicate with each other inside the pellet. Canister. The canister of claim 1, characterized in that filled with a large thermal capacity adsorbent than said main chamber and said second sub-chamber before Symbol first subchamber.

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