JP2004068696A - Canister - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve releasing performance of an evaporating fuel by a simple structure while adsorbing performance of the fuel is maintained. <P>SOLUTION: In a canister 1, air introduced from an atmospheric port 43 is passed through a sub-adsorption chamber 30, and then introduced into a main adsorption chamber 20 continued by detouring a space S formed at its outside. In this case, since the introduced air is warmed by a heater 70 provided in the space S, the releasing performance of the fuel thereafter passing through the chamber 20 can be improved. Since the heater 70 is provided at outside of the chamber 20 and the chamber 30, the active carbons C1, C2 and the adsorption chambers themselves are not directly heated, and the adsorbing performance of the fuel thereafter can be prevented from being lowered or suppressed to be lowered. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a canister that temporarily adsorbs evaporated fuel generated in a fuel tank, separates the fuel at a predetermined timing, and supplies the fuel to an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an automobile using a highly volatile fuel (for example, gasoline), an evaporation system for processing the evaporated fuel in order to prevent the evaporated fuel evaporated in a fuel tank from being released into the atmosphere. Equipped.
[0003]
In such an evaporation system, for example, as shown in FIG. 6, when the internal pressure of the fuel tank 101 becomes higher than a predetermined pressure when the engine is stopped, the tank internal pressure control valve 102 is opened to evaporate the fuel vaporized in the fuel tank 101. Flows into the canister 104 through the evaporation line 103, and the fuel vapor is adsorbed on the activated carbon C in the canister 104. When the engine is operating, the air introduced into the canister 104 through the atmosphere port 106 by the negative pressure of the intake pipe 105 passes through the purge line 107 together with the evaporated fuel released from the activated carbon C, passes through the purge valve 108, passes through the purge valve 108, and flows through the intake pipe 105. Sent to.
[0004]
[Problems to be solved by the invention]
By the way, when the fuel vapor is separated from the activated carbon C as described above, it is generally considered that the air introduced through the atmosphere port 106 is heated by a heater in order to improve the separation performance. That is, as shown in FIGS. 7A to 7C, a heater is provided in the canister, and when the fuel vapor is separated, the heater is energized to enhance the separation performance.
[0005]
However, when the heater is installed in the atmosphere port 106 (air inlet) as in the canister 104a in FIG. 4A, for example, a canister having a two-layer U-shaped structure (see, for example, FIG. 4B). When the method is applied to, the flow path becomes long, and there is a problem that the heat is deprived before the warmed air reaches the main layer (main adsorption chamber).
[0006]
Similarly, when the heater is installed immediately after the air port 106 as in the case of the canister 104b in FIG. 4B, the flow path becomes long when the heater is applied to a canister having a two-layer U-shaped structure or the like. In addition, it is necessary to secure a path for the introduced air immediately after the atmosphere port 106, and there is a problem that the flow path structure therefor becomes complicated.
[0007]
Further, when the heater is installed over the entire length inside the canister as in the canister 104c in FIG. 3C, not only the introduced air but also the activated carbon C is heated. For this reason, although the desorption performance of the evaporated fuel can be improved, there is a problem that the adsorption performance after the engine is stopped is deteriorated.
[0008]
The present invention has been made in view of such a problem, and an object of the present invention is to improve the desorption performance of a canister with a simple structure while maintaining the adsorption performance of the fuel vapor.
[0009]
Means for Solving the Problems and Effects of the Invention
In view of the above problems, a canister of the present invention includes a casing having a plurality of adjacent cylindrical adsorption chambers therein, and an adsorbent is provided in an internal space surrounded by filters provided at both ends of each adsorption chamber. Is filled, and each of the adsorption chambers communicates with each other via one end thereof to form a circulation path,
A charge port for introducing evaporative fuel generated in a fuel system of the internal combustion engine into the casing, and a purge port for purging the evaporative fuel adsorbed by the adsorbent to an intake system of the internal combustion engine, A canister provided so as to communicate with one end of two separated adsorption chambers, and an air port for introducing outside air communicated with an end of the other farthest adsorption chamber,
Inside the casing, air introduced from the atmospheric port into a space provided outside the adsorption chamber at the end opposite to the atmospheric port and communicated with each adsorption chamber via each of the filters. And a heater for heating is provided.
[0010]
That is, in the above configuration, the plurality of adsorption chambers are connected at their ends to form a flow path for the evaporated fuel and the air. Therefore, the evaporated fuel sucked from the charge port is adsorbed by the adsorbent in the process of flowing through each adsorption chamber. Further, the air introduced from the atmospheric port is discharged from the purge port together with the evaporated fuel released in the adsorption chamber.
[0011]
In particular, the air introduced from the atmosphere port passes through the first adsorption chamber and then continues to bypass the space formed outside the adsorption chamber at the end opposite to the atmosphere port in the casing. Introduced into the room. At that time, since the introduced air whose temperature has decreased when passing through the first adsorption chamber is heated by the heater provided in the space, the desorption performance of the evaporated fuel in the adsorption chamber that subsequently passes can be improved.
[0012]
In addition, since the heater is provided outside the adsorption chamber, the heater does not directly heat the adsorbent or the adsorption chamber itself, so that a subsequent decrease in the adsorption performance of the evaporated fuel can be prevented or suppressed. In addition, since the introduced air passes through the space provided with the heater and is introduced into the next adsorption chamber, it is not necessary to form a complicated path for air distribution, and this can be realized with a simple structure. Can be. Therefore, according to the canister of the present invention, the desorbing performance can be improved with a simple structure while maintaining the adsorbing performance of the evaporated fuel.
[0013]
The canister of the present invention may be, for example, one having two adsorption chambers, and having a two-layer U-shaped structure in which the charge port, the purge port, and the atmosphere port are provided on the same side end surface of the casing. An example of this configuration will be described later in an embodiment, but a heater is installed in a detour portion of the U-shaped structure. According to such a configuration, the air is heated at substantially the center of the flow path of the introduced air in the canister, and the evaporated fuel can be efficiently released.
[0014]
In the canister of the present invention, the heater may be mounted on a lid member that closes one end of the casing.
That is, in such a configuration, after forming an adsorption chamber filled with an adsorbent between filters in the casing, the above-described space for heating can be formed by attaching a lid member, and the canister can be easily manufactured. can do.
[0015]
The canister of the present invention may be configured such that the heater abuts a radiator plate mounted on the lid member and heats the air in the space via the radiator plate. According to such a configuration, heat conduction in the space can be improved by the heat sink, and as a result, the desorbing performance of the adsorbent can be further improved.
[0016]
Specifically, in the canister according to the present invention, the lid member covers one end of the casing to form the space, and has a first lid member having an opening at the center thereof, and the first lid member has the space. And a second lid member mounted from the opposite side, wherein the radiator plate is mounted on the first lid member to close the opening, and the heater is opposite to the space of the radiator plate. The second lid member may be attached to the first lid member so as to cover the heat sink and the heater from the outside.
[0017]
According to this configuration, the heater can be mounted after the first lid member is mounted on the main body of the casing, so that failure or breakage of the heater element due to vibration or the like during welding can be prevented.
Further, the lid member includes a first lid member that covers one end of the casing and has an opening at the center thereof, and a second lid member that closes the opening, and the heater is provided on the second lid member. It may be attached.
[0018]
According to this configuration, after the first lid member having a large shape is mounted on the main body of the casing, the second lid member on which the heater is mounted can be mounted. According to this configuration, when the lid member (second lid member) to which the heater is attached is welded, the welding area can be reduced and a relatively small welding force is sufficient. As in the case where the heater element is mounted, failure or breakage of the heater element due to vibration or the like during welding can be prevented.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings to further clarify the embodiments of the present invention. 1 to 3 illustrate the structure of the canister of the present embodiment. FIG. 1A is a side view of the canister, FIG. 1B is a plan view, FIG. 2A is an upper side view, FIG. 2B is a lower side view. FIG. 3A is a sectional view taken along line AA of FIG. 2A, and FIG. 3B is a sectional view taken along line BB of FIG. 2B.
[0020]
As shown in FIGS. 1 and 2, the canister 1 has a cylindrical casing 10 made of a synthetic resin, and a charge port 42, a purge port 41, and an atmosphere port 43, which will be described later, are opened on the upper surface thereof, and the lower surface thereof is provided. The side is closed by a lid member 50 described later. Further, as shown in FIG. 3, a long main adsorption chamber 20 and a sub adsorption chamber 30 which are filled with activated carbons C1 and C2 as adsorbents are provided adjacent to each other inside the canister 1. . In the present embodiment, the volume ratio between the main suction chamber 20 and the sub suction chamber 30 is configured to be about 2: 1.
[0021]
At the left end of the main adsorption chamber 20, a charge port 42 for sucking the evaporated fuel generated in the fuel system of the internal combustion engine into the casing 10, and a purge port for the evaporated fuel adsorbed on the activated carbons C1 and C2 to the intake system of the internal combustion engine. A purge port 41 is provided in communication with the purge port 41. The upper end of the main suction chamber 20 is slightly contracted to form a locking portion 20a, and a plate-like filter 21 having a shape substantially equal to the cross section of the main suction chamber 20 is locked to the locking portion 20a. Have been. At the lower end of the main adsorption chamber 20, a filter 22 having the same shape as the filter 21 is provided, and a space sandwiched between the filters 21 and 22 is filled with activated carbon C1 as an adsorbent. Further, a support plate 23 is disposed in contact with the lower surface of the filter 22, and a coil spring 24 is interposed between the support plate 23 and the cover member 50. Therefore, an appropriate compressive force is applied to the activated carbon C1 via the filters 21 and 22 by the urging force of the coil spring 24.
[0022]
In this embodiment, as the activated carbon C1 filled in the main adsorption chamber 20, a high adsorption activated carbon having a higher adsorption capacity than the activated carbon C2 charged in the sub adsorption chamber 30 is used.
On the other hand, an air port 43 for introducing outside air is provided at the upper end of the sub adsorption chamber 30 so as to communicate therewith. Similarly, in the sub-adsorption chamber 30, the left end portion is slightly contracted to form a locking portion 30a, and a plate-shaped filter 31 having a shape substantially equal to the cross section of the sub-adsorption chamber 30 is used. Locked to the portion 30a. A filter 32 having the same shape as the filter 31 is provided at the lower end of the sub-adsorption chamber 30, and the space between the filters 31 and 32 is filled with activated carbon C2 as an adsorbent. Further, a support plate 33 is disposed in contact with the lower surface of the filter 32, and a coil spring 34 is interposed between the support plate 33 and the cover member 50. Therefore, an appropriate compressive force is applied to the activated carbon C2 via the filters 31 and 32 by the urging force of the coil spring 34.
[0023]
The lid member 50 includes a first lid member 51 that covers one end of the casing 10 and has an opening 51a at the center thereof, and a second lid member 52.
The first lid member 51 has a cap shape protruding into the inside of the casing 10, and has a plurality of ribs 51b for reinforcement provided on the back surface thereof (see FIG. 2B). A plate-shaped heat radiating plate 60 made of an aluminum material is fitted and mounted in the opening 51a, and a plurality of fins 60a extend from a surface of the heat radiating plate 60 facing the inside of the casing 10. When attaching the first lid member 51 to the casing 10, the peripheral edge of the first lid member 51 is removed from one end of the casing 10 in a state where the heat sink 60 is formed integrally with the first lid member 51 in advance. The flange portion 10a extending in the direction is brought into contact. Then, the first lid member 51 is mounted on the casing 10 by performing vibration welding along the peripheral edge of the first lid member 51. Thereafter, a heater 70 made of a plate-shaped resistance heating element (for example, a PTC element: Positive Temperature Coefficient) is attached to the heat sink 60. At this time, the heater 70 contacts the surface of the heat sink 60 opposite to the fins 60a. The heater 70 is connected to a power source (not shown) via a lead wire 71 and a terminal 72 shown in FIG.
[0024]
On the other hand, the second lid member 52 has a cap shape protruding outward from the casing 10, has a smaller thickness than the first lid member 51, and has an outer shape slightly larger than the opening 51 a. When attaching the second lid member 52 to the opening 51a of the first lid member 51, the peripheral edge of the second lid member 52 is brought into contact with the vicinity of the opening 51a so as to cover the heater 70 previously attached to the heat sink 60. Contact And it mount | wears by giving an ultrasonic welding along the said peripheral edge.
[0025]
As described above, first, the first lid member 51 integrated with the radiator plate 60 is vibration-welded to the casing 10, and then the heater 70 is mounted on the radiator plate 60, and then, the second lid member 51 smaller than the first lid member 51 is formed. Since the lid member 52 is ultrasonically welded to the first lid member 51, it is possible to suppress or prevent vibration from being applied to the heater 70 during welding, and to prevent the heater 70 from being broken down or damaged. .
[0026]
Thus, one end of the casing 10 is closed by the lid member 50, and a space S is formed between the main adsorption chamber 20 and the sub adsorption chamber 30 and the lid member 50 via the filters 22 and 32. Therefore, when a heater (not shown) is turned on and the heater 70 is turned on, the air flowing through the space S is warmed by heat conduction through the radiator plate 60.
[0027]
Next, the operation of the canister of this embodiment will be described. For example, the evaporated fuel introduced into the main adsorption chamber 20 through the filter 21 from the charge port 42 when the engine of the automobile is stopped is adsorbed by the activated carbon C1 inside the main adsorption chamber 20. Further, the evaporated fuel that has passed through the activated carbon C1 and the filter 22 bypasses the space S, further passes through the filter 32, is introduced into the sub adsorption chamber 30, and is adsorbed by the activated carbon C2 inside the sub adsorption chamber 30. At this time, since the heater 70 is off, the suction performance of the canister 1 is ensured.
[0028]
On the other hand, when the engine is operating, the heater 70 is turned on. For this reason, the air introduced into the sub-adsorption chamber 30 through the filter 31 from the atmosphere port 43 separates the evaporated fuel adsorbed on the activated carbon C2, passes through the filter 32 together with the evaporated fuel, and bypasses the space S. Then, it passes through the filter 22 and is introduced into the main adsorption chamber 20. At that time, the introduced air whose temperature has decreased in the sub adsorption chamber 30 is heated in the space S, and thus the heated air is introduced into the main adsorption chamber 20. Therefore, the fuel vapor adsorbed on the activated carbon C1 in the main adsorption chamber 20 is easily released. Then, the separated evaporated fuel is sent out from the purge port 41 together with the air, and reaches the intake system of the internal combustion engine.
[0029]
As described above, in the canister 1 of the present embodiment, the air introduced from the atmosphere port 43 passes through the sub-adsorption chamber 30 and then bypasses the space S formed outside the sub-adsorption chamber 30 to continue. 20 is introduced. At this time, the introduced air whose temperature has been lowered in the sub-adsorption chamber 30 is heated by the heater 70 provided in the space S, so that the evaporative fuel can be easily separated in the main adsorption chamber 20 that passes thereafter, and the separation performance of the canister 1 can be improved. Can be improved. In particular, as described above, high adsorption type activated carbon is used in the main adsorption chamber 20, and its adsorption capacity is extremely high, and adsorbs a large amount of evaporated fuel. For this reason, a large amount of the evaporated fuel adsorbed there can be released by the action of the air heated by the heater 70, so that the canister can maintain a high adsorption capacity.
[0030]
Further, since the heater 70 is provided outside the main adsorption chamber 20 and the sub adsorption chamber 30, the heater 70 does not directly heat the activated carbons C1 and C2 or the adsorption chamber itself, and thereafter adsorbs the evaporated fuel in each adsorption chamber. A decrease in performance can be prevented or suppressed.
[0031]
Further, since the introduced air passes through the space S in which the heater 70 is provided and is introduced into the main suction chamber 20, it is not necessary to form a complicated path for air distribution, and this is realized with a simple structure. can do.
Therefore, according to the canister 1 of the present embodiment, it is possible to improve the desorbing performance with a simple structure while maintaining the adsorbing performance of the evaporated fuel.
[0032]
The embodiments of the present invention have been described above. However, the embodiments of the present invention are not limited to the above-described embodiments, but may take various forms within the technical scope of the present invention. Nor.
For example, in the above-described embodiment, an example in which the present invention is applied to a so-called double-layer U-shaped canister in which the main suction chamber 20 and the sub suction chamber 30 are connected at one end has been described, but there are three or more suction chambers. It is also possible to apply to a three-layer N-shaped structure, a four-layer W-shaped structure and other canisters.
[0033]
Specifically, for example, as in a three-layer N-shaped structure conceptually shown in FIG. 4A, a detour of the air introduced from the atmosphere port, that is, the spaces S1 and S2 formed outside each adsorption chamber. Heaters may be installed in each of the sections to heat the introduced air. Also, as in the four-layer W-shaped structure shown in FIG. 5A, a detour of the introduced air located on the opposite side to the atmosphere port, that is, a space S31 formed outside each adsorption chamber (right side in the figure). , S32, the heaters are airtightly arranged so as to straddle the boundary between the second layer and the third layer, and the heat sinks are respectively disposed in the spaces S31, S32 on both sides of the boundary of the heater. It may be configured so that air can be heated. In this case, since the space S31 and the space S32 forming the detour are separated by the heater, the introduced air can flow along the W-shaped path (arrow in the drawing).
[0034]
Alternatively, as shown in FIG. 3B, the boundary between the second layer and the third layer is air-tightly partitioned by a heat sink, and a heater is attached to the rear surface of the heat sink (the side opposite to the spaces S33 and S34). Alternatively, as shown in FIG. 4C, the boundary between the second layer and the third layer is completely separated by the walls of the suction chambers, and the two heaters are provided in the spaces S35 and S36. It may be arranged.
[0035]
In the above embodiment, the main suction chamber 20 and the sub suction chamber 30 are separated by the filters 22 and 32 and communicate with each other through the space S (see FIG. 3). As shown in ()), the partition at one end may be removed so as to partially communicate inside the adsorption chamber. In this case, a part of the introduced air detours in the adsorption chamber, but the air passing through the space S4 formed outside (right side in the drawing) of each adsorption chamber is heated by the heater, so that the performance of releasing the evaporated fuel is improved. be able to.
[0036]
Although not described in the above embodiment, a separate heater may be provided for the atmosphere port, and pre-warmed air may be introduced into the canister.
Further, in the above-described embodiment, the example in which the vibration welding and the ultrasonic welding are performed when the lid member 50 (the first lid member 51 and the second lid member 52) is mounted has been described. However, the laser welding may be used.
[Brief description of the drawings]
FIG. 1 is a plan view and a front view of a canister according to an embodiment of the present invention.
FIG. 2 is a side view of the canister according to the embodiment.
FIG. 3 is a sectional view of a canister according to the embodiment.
FIG. 4 is a sectional view of a canister according to a modification.
FIG. 5 is a sectional view of a canister according to a modification.
FIG. 6 is an explanatory diagram showing an example of an evaporation system to which a canister is applied.
FIG. 7 is an explanatory diagram showing a problem of a conventional canister.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Canister, 10 ... Casing, 20 ... Main adsorption chamber,
21, 22, 31, 32 ... filter, 23, 33 ... support plate,
24, 34: coil spring, 30: sub suction chamber, 33: support plate, 41: charge port, 42: purge port,
43 ... atmosphere port, 50 ... lid member, 51 ... first lid member,
52: second lid member, 60: heat sink, 70: heater,
C1. C2: activated carbon, S: space

Claims (5)

A casing having a plurality of adjacent cylindrical adsorption chambers therein is provided, and an internal space surrounded by filters disposed at both ends of each adsorption chamber is filled with an adsorbent, and each of the adsorption chambers is Forming a distribution channel by communicating with each other via one end thereof,
A charge port for introducing evaporative fuel generated in a fuel system of the internal combustion engine into the casing, and a purge port for purging the evaporative fuel adsorbed by the adsorbent to an intake system of the internal combustion engine, A canister provided so as to communicate with one end of two separated adsorption chambers, and an air port for introducing outside air communicated with an end of the other farthest adsorption chamber,
Inside the casing, air introduced from the atmospheric port into a space provided outside the adsorption chamber at the end opposite to the atmospheric port and communicated with each adsorption chamber via each of the filters. A canister provided with a heater for heating the canister. Comprising two said adsorption chambers,
2. The canister according to claim 1, wherein the charge port, the purge port, and the atmosphere port are configured in a two-layer U-shape provided on the same side end surface of the casing. 3. The canister according to claim 1, wherein the heater is mounted on a lid member that closes one end of the casing. 4. The canister according to claim 3, wherein the heater is configured to contact a radiator plate mounted on the lid member, and heat the air in the space via the radiator plate. 5. The lid member covers one end of the casing to form the space, and has a first lid member having an opening at the center thereof, and a second lid member mounted on the first lid member from the side opposite to the space. With a lid member,
The radiator plate is mounted on the first lid member to close the opening, and the heater is mounted on a surface of the radiator plate opposite to the space,
The canister according to claim 4, wherein the second lid member is attached to the first lid member so as to cover the heat sink and the heater from the outside.

Images