Canister

Abstract

To improve adsorption efficiency of fuel vapor with a simple configuration with respect to a canister.SOLUTION: A canister 1 as a canister 1 attached to an engine includes a main chamber 2, an auxiliary chamber 3, a positive pressure valve 5, and a negative pressure valve 6. The main chamber 2 has a first porous body 27 built therein and is connected to an induction system of the engine and a fuel tank. The auxiliary chamber 3 has a second porous body 28 built therein and is opened to the atmosphere. The positive pressure valve 5 and the negative pressure valve 6 are provided between the main chamber 2 and the auxiliary chamber 3. The positive pressure valve 5 functions as a nonreturn valve to be opened when a differential pressure of the main chamber 2 to the auxiliary chamber 3 exceeds a positive first threshold value, and the negative pressure valve 6 functions as a nonreturn valve to be opened when a differential pressure of the main chamber 2 to the auxiliary chamber 3 is less than a negative second threshold value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a canister attached to an engine.

Background Art

[0002] Conventionally, in an engine (internal combustion engine) that obtains power by burning volatile fuel, a canister (charcoal canister, carbon canister, vapor collector) for recovering fuel vapor (fuel gas, hydrocarbon vapor) evaporated in a fuel tank is known. Inside the canister, a porous body such as activated carbon or zeolite that temporarily adsorbs fuel vapor is incorporated. The fuel vapor adsorbed on the porous body desorbs during the operation of the engine and is sucked into the intake system (intake passage) and introduced into the combustion chamber (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional canister, there may be a bias in the flow of fuel vapor inside the porous body. For example, among the interior of the porous body, the part where fuel vapor is likely to be adsorbed tends to be biased near the tank port connected to the fuel tank. On the other hand, the part where fuel vapor is likely to desorb is the part near the purge port connected to the intake system of the engine inside the porous body. Therefore, good adsorption and desorption efficiency can be obtained only in the part near both the tank port and the purge port, and there is a problem that the entire porous body cannot be effectively utilized. This problem leads to an increase in the filling amount of the porous body and an increase in the weight of the canister.

[0005] One of the objectives of this invention is to provide a canister that has been devised in light of the above-mentioned problems and can improve the adsorption and desorption efficiency of fuel vapor with a simple configuration. In addition to this objective, another objective of this invention is to achieve effects that cannot be obtained with conventional technology, which are derived from the various configurations shown in the "Modes for Carrying Out the Invention" described later. [Means for solving the problem]

[0006] The disclosed canister can be implemented in the manner or application described below and solves at least some of the above problems. The disclosed canister is a canister attached to an engine, comprising: a main chamber containing a first porous body and connected to the engine's intake system and fuel tank; a sub-chamber containing a second porous body and open to the atmosphere; a positive pressure valve provided between the main chamber and the sub-chamber, which functions as a check valve and is opened when the differential pressure of the main chamber with respect to the sub-chamber exceeds a positive first threshold; and a negative pressure valve provided between the main chamber and the sub-chamber, which functions as a check valve and is opened when the differential pressure of the main chamber with respect to the sub-chamber is less than a negative second threshold. A plate that is movable inside the main chamber, and a spring that biases the plate toward the first porous body. It is equipped with. The positive pressure valve and the negative pressure valve are provided on the plate. [Effects of the Invention]

[0007] In the disclosed canister, when the differential pressure between the main chamber and the sub-chamber is below the first threshold and above the second threshold, the main chamber can be sealed, and fuel vapor can be circulated within the main chamber. This allows fuel vapor to be adsorbed onto the entire first porous body and desorbed from the entire first porous body. Therefore, unevenness in fuel adsorption and desorption onto the first porous body can be suppressed, and the adsorption and desorption efficiency of fuel vapor can be improved with a simple configuration.

[0008] Furthermore, when the differential pressure between the main chamber and the sub-chamber exceeds the first threshold, fuel vapor from the main chamber can be circulated into the sub-chamber, allowing the fuel vapor to be recovered by the second porous material while simultaneously lowering the pressure in the main chamber. On the other hand, when the differential pressure is below the second threshold, fuel vapor and outside air can be circulated from the sub-chamber to the main chamber, introducing fuel vapor into the engine's intake system while simultaneously increasing the pressure in the main chamber. Therefore, it becomes easier to maintain a sealed state in the main chamber, and the adsorption and desorption efficiency of fuel vapor can be improved with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This is a longitudinal cross-sectional view illustrating the configuration of a canister as an example. [Figure 2] This is a close-up longitudinal cross-sectional view of the main part of the canister shown in Figure 1. [Figure 3] (A) is a longitudinal cross-sectional view showing the fuel vapor flow in a conventional canister (comparative example), and (B) is a longitudinal cross-sectional view showing the fuel vapor flow in the canister of Figure 1 (when the positive pressure valve and negative pressure valve are closed). [Figure 4] (A) is a longitudinal cross-sectional view showing the fuel vapor flow in the canister of Figure 1 (when the positive pressure valve is open), and (B) is a longitudinal cross-sectional view showing the fuel vapor flow in the canister of Figure 1 (when the negative pressure valve is open). [Figure 5] (A) to (D) are horizontal cross-sectional views (top views of the first and second plates) illustrating the structure of the canister. [Modes for carrying out the invention]

[0010] The disclosed canister may be implemented by the following embodiments. The disclosed canister is attached to an engine. The engine as referred to herein includes various internal combustion engines that operate on volatile fuels, such as gasoline engines and jet engines. The canister of this embodiment is attached to an engine mounted on a vehicle. With regard to the definition of direction in the embodiments, the direction of the components and parts constituting the canister means the direction when it is mounted on a vehicle, unless otherwise specified. [Examples]

[0011] [1. Structure] Figure 1 is a longitudinal cross-sectional view illustrating the configuration of a canister 1 as an embodiment. This canister 1 comprises a main chamber 2 and a sub-chamber 3 inside a casing 20. The casing 20 has a casing body formed in the shape of a container with an open top, and a lid member that is integrally fixed to the casing body in a closed state. The material of the casing 20 is, for example, metal or synthetic resin. The overall shape of the casing 20 is formed in the shape of a cylinder (a tubular shape with a hollow interior, including hollow cylindrical shapes and hollow elliptical cylindrical shapes) or a prismatic shape.

[0012] As shown in Figure 1, a partition wall 21 is erected inside the casing 20. One space separated by the partition wall 21 becomes the main room 2, and the other space becomes the sub-room 3. The height of the partition wall 21 is set to a height such that the main room 2 and the sub-room 3 are not completely separated. In other words, a predetermined gap is formed between the upper end of the partition wall 21 and the uppermost surface (ceiling) inside the casing 20. Preferably, the horizontal position of the partition wall 21 is set so that the main room 2 is wider than the sub-room 3.

[0013] The main chamber 2 is a chamber containing the first porous body 27 and is connected to the engine's intake system and fuel tank. The first porous body 27 is, for example, a solid porous body having interconnected bubbles, and includes activated carbon or zeolite for temporarily adsorbing fuel vapor. The first porous body 27 is formed to a shape corresponding to the internal shape of the main chamber 2 and is inserted into the lower part of the main chamber 2 without any gaps. At the lower end of the main chamber 2, a tank port 22 communicating with the fuel tank and a purge port 23 communicating with the engine's intake system are provided. These tank port 22 and purge port 23 are located below the first porous body 27.

[0014] Sub-chamber 3 is a chamber containing the second porous body 28 and is open to the atmosphere. The second porous body 28, like the first porous body 27, is a solid porous body having, for example, interconnected air bubbles. The second porous body 28 may be the same type of porous body as the first porous body 27, or it may be a different type of porous body. The second porous body 28 is formed in a shape corresponding to the internal shape of sub-chamber 3 and is inserted into the lower part of sub-chamber 3 without any gaps. An atmospheric port 24 that opens to the atmosphere is provided at the lower end of sub-chamber 3. The atmospheric port 24 is positioned below the second porous body 28. The first porous body 27 and the second porous body 28 may be solid porous bodies (molded products), or they may be powdered or granular materials sealed in a breathable bag.

[0015] A first plate 7 (plate) and a first spring 25 (spring) are provided above the first porous body 27. The first plate 7 is a plate-shaped member that is movable vertically inside the main chamber 2. The first spring 25 is an elastic member (for example, a coil spring or rubber) that biases the first plate 7 downward toward the first porous body 27. The biasing force of the first spring 25 causes the first plate 7 to press downward toward the upper end surface of the first porous body 27. As a result, the first porous body 27 is stably fixed inside the main chamber 2.

[0016] Similarly, a second plate 8 and a second spring 26 are provided above the second porous body 28. The second plate 8 is a plate-shaped member that is movable vertically within the sub-chamber 3 and biased downward by the second spring 26. The second plate 8 presses the second porous body 28 downward while in surface contact with the upper end surface of the second porous body 28. This stably fixes the second porous body 28 within the sub-chamber 3.

[0017] The portion above the first plate 7 inside the main chamber 2 is integrally connected to the portion above the second plate 8 inside the sub-chamber 3. This integrally connected space (the space above the first plate 7 and the second plate 8 inside the internal space of the casing 20) is called the spring chamber 4. The spring chamber 4 is a space where the first spring 25 and the second spring 26 are arranged. The first spring 25 is inserted in a compressed state between the first plate 7 and the ceiling surface of the main chamber 2, and the second spring 26 is inserted in a compressed state between the second plate 8 and the ceiling surface of the sub-chamber 3.

[0018] A through-hole 9 penetrating the front and back surfaces is provided in the second plate 8. The through-hole 9 functions as a passage connecting the spring chamber 4 and the sub-chamber 3. As a result, the internal pressures of the sub-chamber 3 and the spring chamber 4 are equal and also equal to the ambient atmospheric pressure. Note that the biasing force of the first spring 25 is set to a magnitude such that it cannot be pushed back by changes in the atmospheric pressure or the internal pressure of the main chamber 2.

[0019] A positive pressure valve 5 and a negative pressure valve 6 are incorporated in the first plate 7. The positive pressure valve 5 is a check valve that is opened only when the internal pressure of the main chamber 2 is greater than the internal pressures of the sub-chamber 3 and the spring chamber 4. The positive pressure valve 5 of this embodiment is opened when the differential pressure (gauge pressure, the value obtained by subtracting the internal pressure of the sub-chamber 3 from the internal pressure of the main chamber 2) of the main chamber 2 with respect to the sub-chamber 3 exceeds a positive first threshold value. That is, when the main chamber 2 is at a higher pressure than the sub-chamber 3 and the absolute value of the pressure difference is large enough, the flow of fuel vapor from the main chamber 2 to the sub-chamber 3 is allowed. On the other hand, when the differential pressure is below the first threshold value, the closed state of the positive pressure valve 5 is maintained.

[0020] The negative pressure valve 6 is a check valve that opens only when the internal pressure of the main chamber 2 is smaller than the internal pressures of the sub-chamber 3 and the spring chamber 4. In this embodiment, the negative pressure valve 6 opens when the differential pressure of the main chamber 2 relative to the sub-chamber 3 (gauge pressure, the value obtained by subtracting the internal pressure of the sub-chamber 3 from the internal pressure of the main chamber 2) is less than a negative second threshold. In other words, when the main chamber 2 is at a lower pressure than the sub-chamber 3 and the absolute value of the pressure difference is large enough, the flow of outside air (or fuel vapor) from the sub-chamber 3 to the main chamber 2 is permitted. On the other hand, when the differential pressure is below the first threshold, the positive pressure valve 5 remains closed.

[0021] Figure 2 is a magnified longitudinal cross-sectional view showing the main parts of the canister 1 (around the positive pressure valve 5 and negative pressure valve 6). The positive pressure valve 5 is provided with a positive pressure control chamber 10, a positive pressure inlet hole 11, a positive pressure outlet hole 12, a positive pressure plate 13, and a positive pressure spring 14. The negative pressure valve 6 is provided with a negative pressure control chamber 15, a negative pressure inlet hole 16, a negative pressure outlet hole 17, a negative pressure plate 18, and a negative pressure spring 19. The positive pressure valve 5 and the negative pressure valve 6 are positioned above the first porous body 27.

[0022] The positive pressure control chamber 10 is a hollow section located inside the first plate 7. A positive pressure inlet hole 11 is provided on the main chamber 2 side of the positive pressure control chamber 10, connecting the positive pressure control chamber 10 and the main chamber 2. A positive pressure outlet hole 12 is provided on the spring chamber 4 side of the positive pressure control chamber 10, connecting the positive pressure control chamber 10 and the spring chamber 4. The positive pressure outlet hole 12 is always open. On the other hand, the positive pressure inlet hole 11 is closed from the inside (positive pressure control chamber 10 side) by the positive pressure plate 13 and the positive pressure spring 14. The positive pressure spring 14 is an elastic member (for example, a coil spring or rubber) that biases the positive pressure plate 13 downward toward the positive pressure inlet hole 11. The biasing force of the positive pressure spring 14 presses the positive pressure plate 13 against the positive pressure inlet hole 11, maintaining the closed state of the positive pressure inlet hole 11.

[0023] Similar to the positive pressure control chamber 10, the negative pressure control chamber 15 is a hollow section located inside the first plate 7. A negative pressure inlet hole 16 is provided on the spring chamber 4 side of the negative pressure control chamber 15, connecting the negative pressure control chamber 15 and the spring chamber 4. A negative pressure outlet hole 17 is provided on the main chamber 2 side of the negative pressure control chamber 15, connecting the negative pressure control chamber 15 and the main chamber 2. The negative pressure outlet hole 17 is always open. On the other hand, the negative pressure inlet hole 16 is closed from the inside (negative pressure control chamber 15 side) by the negative pressure plate 18 and the negative pressure spring 19. The negative pressure spring 19 is an elastic member that biases the negative pressure plate 18 upward toward the negative pressure inlet hole 16. The biasing force of the negative pressure spring 19 presses the negative pressure plate 18 against the negative pressure inlet hole 16, maintaining the closed state of the negative pressure inlet hole 16.

[0024] Regarding the specifications of the positive pressure valve 5, the opening pressure (first threshold) of the positive pressure inlet hole 11 in this embodiment is set to, for example, 10 [kPa]. The valve dimensions (size of the positive pressure inlet hole 11, pressure receiving area of ​​the positive pressure plate 13) are set to φ20 [mm], and the load acting on the positive pressure spring 14 is set to 3 [N]. The amount of movement of the positive pressure spring 14 when the valve is open is set to 5 [mm], and the spring constant of the positive pressure spring 14 is set to 0.6 [N / mm].

[0025] Regarding the specifications of the negative pressure valve 6, the opening pressure (second threshold) of the negative pressure inlet hole 16 in this embodiment is set to, for example, -10 [kPa]. The valve dimensions (size of the negative pressure inlet hole 16, pressure receiving area of ​​the negative pressure plate 18) are set to φ20 [mm], and the load acting on the negative pressure spring 19 is set to 3 [N]. The amount of movement of the negative pressure spring 19 when the valve is open is set to 5 [mm], and the spring constant of the negative pressure spring 19 is set to 0.6 [N / mm]. Note that the various characteristic values ​​of the positive pressure valve 5 and negative pressure valve 6 shown here are only one example of what can be set.

[0026] [2. Effect] Figure 3(A) is a longitudinal cross-sectional view showing the flow of fuel vapor in a conventional canister 50 (comparative example). This canister 50 incorporates a pressure plate 51 instead of the first plate 7, without a positive pressure valve 5 or a negative pressure valve 6. The pressure plate 51 is provided with multiple through holes 52 that penetrate both its front and back surfaces. As a result, the fuel vapor flowing from the tank port 22 into the main chamber 2 flows towards each of the through holes 52, as shown by the thick arrows in Figure 3(A).

[0027] On the other hand, in Figure 3(A), almost no fuel vapor flows into the lower right portion of the main chamber 2. Therefore, fuel vapor is adsorbed only in the upper left portion of the main chamber 2 in Figure 3(A) of the first porous body 27, and the entire first porous body 27 is not being effectively utilized. The fuel vapor that passes through each through-hole 52 remains inside the spring chamber 4 or is introduced into the sub-chamber 3 and adsorbed by the second porous body 28.

[0028] Figure 3(B) is a longitudinal cross-sectional view showing the flow of fuel vapor in the canister 1 of this embodiment. In this embodiment, a positive pressure valve 5 and a negative pressure valve 6 are provided on the first plate 7. The positive pressure valve 5 remains closed as long as the differential pressure of the main chamber 2 relative to the sub-chamber 3 does not exceed a positive first threshold. The negative pressure valve 6 is not opened as long as the gauge pressure of the main chamber 2 is positive. As a result, the fuel vapor that flows into the main chamber 2 from the tank port 22 circulates inside the main chamber 2, as shown by the thick arrows in Figure 3(B), and is adsorbed onto the entire first porous body 27. Therefore, the entire first porous body 27 is effectively utilized.

[0029] Furthermore, as long as the positive pressure valve 5 and the negative pressure valve 6 are closed, fuel vapor does not leak into the spring chamber 4, thus improving the adsorption efficiency of fuel vapor to the entire first porous body 27. Subsequently, when fuel vapor flows out from the main chamber 2 to the purge port 23, the components detached from the entire first porous body 27 are introduced into the engine. Therefore, the desorption efficiency of fuel vapor from the entire first porous body 27 is improved.

[0030] Figure 4(A) is a longitudinal cross-sectional view of the canister 1 showing the flow of fuel vapor when the positive pressure valve 5 is open. When the differential pressure of the main chamber 2 relative to the sub-chamber 3 exceeds a positive first threshold, the positive pressure valve 5 opens. As a result, fuel vapor flows out from the main chamber 2 to the sub-chamber 3, is adsorbed by the second porous body 28, and the internal pressure of the main chamber 2 decreases. Subsequently, when the differential pressure of the main chamber 2 relative to the sub-chamber 3 falls below the first threshold, the positive pressure valve 5 closes again, resulting in the state shown in Figure 3(B).

[0031] Figure 4(B) is a longitudinal cross-sectional view of the canister 1 showing the flow of fuel vapor when the negative pressure valve 6 is open. When the differential pressure of the main chamber 2 relative to the sub-chamber 3 falls below the negative second threshold, the negative pressure valve 6 opens. As a result, outside air (or fuel vapor containing fuel components detached from the second porous body 28) flows from the sub-chamber 3 to the main chamber 2, and the internal pressure of the main chamber 2 increases. At this time, the fuel vapor inside the main chamber 2 is introduced into the engine's intake system via the purge port 23. Subsequently, when the differential pressure of the main chamber 2 relative to the sub-chamber 3 rises above the second threshold, the negative pressure valve 6 closes again, resulting in the state shown in Figure 3(B).

[0032] [3. Effects] (1) The canister 1 of this embodiment is a canister 1 attached to an engine and comprises a main chamber 2, a sub-chamber 3, a positive pressure valve 5, and a negative pressure valve 6. The main chamber 2 contains a first porous body 27 and is connected to the engine's intake system and fuel tank. The sub-chamber 3 contains a second porous body 28 and is open to the atmosphere. The positive pressure valve 5 and the negative pressure valve 6 are provided between the main chamber 2 and the sub-chamber 3. The positive pressure valve 5 functions as a check valve that opens when the differential pressure of the main chamber 2 with respect to the sub-chamber 3 exceeds a positive first threshold, and the negative pressure valve 6 functions as a check valve that opens when the differential pressure of the main chamber 2 with respect to the sub-chamber 3 is less than a negative second threshold.

[0033] With the above configuration, when the differential pressure between the main chamber 2 and the sub-chamber 3 is below the first threshold and above the second threshold, the main chamber 2 can be sealed, and fuel vapor can be circulated inside the main chamber 2. This allows fuel vapor to be adsorbed onto the entire first porous body 27, and fuel vapor to be desorbed from the entire first porous body 27. Therefore, unevenness in fuel adsorption and desorption onto the first porous body 27 can be suppressed, and the efficiency of fuel vapor adsorption and desorption can be improved with a simple configuration. Consequently, the fuel efficiency and environmental performance of the engine can be improved, and the environmental impact and running costs of vehicles equipped with this engine can be reduced.

[0034] Furthermore, when the differential pressure between the main chamber 2 and the sub-chamber 3 exceeds the first threshold, the fuel vapor in the main chamber 2 can be circulated into the sub-chamber 3, allowing the fuel vapor to be adsorbed onto the second porous body 28 while simultaneously lowering the pressure in the main chamber 2. On the other hand, when the differential pressure is below the second threshold, fuel vapor and outside air can be circulated from the sub-chamber 3 into the main chamber 2, introducing fuel vapor into the engine's intake system while simultaneously increasing the pressure in the main chamber 2. Therefore, it becomes easier to maintain a sealed state of the main chamber 2, and the adsorption and desorption efficiency of fuel vapor can be improved with a simple configuration.

[0035] (2) The canister 1 of this embodiment includes a first plate 7 (plate) that is movable inside the main chamber 2, and a first spring 25 (spring) that fixes the first porous body 27 by biasing the first plate 7 toward the first porous body 27. The positive pressure valve 5 and the negative pressure valve 6 are provided on the first plate 7. With this configuration, the canister 1 of this embodiment can be manufactured simply by changing the pressing plate 51 of an existing canister 50, such as the one shown in Figure 3(A), thereby reducing product costs.

[0036] Furthermore, if we consider placing the positive pressure valve 5 and negative pressure valve 6 in locations other than the first plate 7, for example, it is conceivable to completely separate the main chamber 2 and the sub-chamber 3 with a partition wall 21 and place the positive pressure valve 5 and negative pressure valve 6 on top of the partition wall 21. However, in this case, the casing 20 itself would have to be redesigned, which would increase product costs. In contrast, by placing the positive pressure valve 5 and negative pressure valve 6 on the first plate 7, the canister 1 of this embodiment can be easily realized without changing the structure of the casing 20 or the sub-chamber 3.

[0037] (3) The main chamber 2 of this embodiment has a tank port 22 that communicates with the fuel tank and a purge port 23 that communicates with the engine's intake system. As shown in Figure 1, these tank port 22 and purge port 23 are positioned below the first porous body 27. On the other hand, the positive pressure valve 5 and the negative pressure valve 6 are positioned above the first porous body 27. With this configuration, when the positive pressure valve 5 is closed, the flow of fuel vapor can be easily spread throughout the interior of the main chamber 2, improving the adsorption and desorption efficiency of fuel vapor. In addition, by utilizing the action of gravity, fuel vapor can easily flow to the lower purge port 23, allowing fuel vapor to be efficiently introduced into the engine's intake system.

[0038] [4. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude the application of various modifications and technologies not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed. For example, the shape of the casing 20 and the number of positive pressure valves 5 and negative pressure valves 6 can be arbitrarily set. The shapes of the main chamber 2 and sub-chamber 3 can also be arbitrarily set.

[0039] Figures 5(A) to 5(D) are horizontal cross-sectional views (top views of the first plate 7 and the second plate 8) illustrating the structure of canister 1. Figures 5(A) and 5(C) show canister 1 with a prismatic casing 20, while Figures 5(B) and 5(D) show canister 1 with a cylindrical casing 20. Furthermore, Figures 5(A) and 5(B) show canister 1 with one positive pressure valve 5 and one negative pressure valve 6, while Figures 5(C) and 5(D) show canister 1 with multiple positive pressure valves 5 and multiple negative pressure valves 6.

[0040] By increasing the number of positive pressure valves 5, the uneven distribution of fuel vapor flow when the positive pressure valves 5 are open can be reduced. Similarly, by increasing the number of negative pressure valves 6, the uneven distribution of fuel vapor and outside air flow when the negative pressure valves 6 are open can be reduced. Therefore, by providing multiple positive pressure valves 5 and negative pressure valves 6, the uneven distribution of fuel vapor can be reduced, and the adsorption and desorption efficiency can be further improved. In order to reduce the uneven distribution of fuel vapor flow, the positive pressure valves 5 and negative pressure valves 6 may be arranged in a dispersed manner, or they may be arranged symmetrically (line symmetry, point symmetry, rotational symmetry) when viewed from above.

[0041] Furthermore, although the above embodiment illustrates a canister 1 equipped with a first plate 7 (plate) and a first spring 25, these may be omitted. In this case, the positive pressure valve 5 and the negative pressure valve 6 are provided between the main chamber 2 and the sub-chamber 3. At a minimum, by providing the positive pressure valve 5 and the negative pressure valve 6 between the main chamber 2 and the sub-chamber 3, it is possible to realize a canister 1 that provides the same effects as in the above embodiment.

[0042] In the above embodiment, a canister 1 in which the tank port 22 and purge port 23 are positioned below the first porous body 27 is illustrated, but the connection positions of the tank port 22 and purge port 23 are not limited to this configuration. Also, in the above embodiment, a canister 1 in which the positive pressure valve 5 and negative pressure valve 6 are positioned above the first porous body 27 is illustrated, but the placement positions of the positive pressure valve 5 and negative pressure valve 6 are not limited to this configuration. [Industrial applicability]

[0043] This technology is applicable to the manufacturing industry of canisters attached to engines, and to the manufacturing industry of vehicles equipped with engines and canisters. It is also applicable to the manufacturing industry of industrial machinery and power generation equipment equipped with engines and canisters. [Explanation of Symbols]

[0044] 1 Canister 2 Main room 3 Antechamber 4 Spring chamber 5. Positive pressure valve 6. Negative pressure valve 7. First Plate (Plate) 8. Second Plate 9 Communication hole 10 Positive Pressure Control Room 11 Positive pressure inlet hole 12 Positive pressure outlet hole 13 Positive pressure plate 14. Positive pressure spring 15. Negative Pressure Control Room 16. Negative pressure inlet hole 17. Negative pressure outlet hole 18. Negative pressure plate 19. Negative pressure spring 20 Casing 21 Bulkhead 22 Tank Ports 23 Purge Port 24 Atmospheric Ports 25. First Spring (Spring) 26 Second Spring 27 First porous body 28 Second porous body

Claims

1. A canister attached to an engine, The main chamber, which incorporates a first porous body and is connected to the intake system and fuel tank of the engine, It contains a second porous body and a sub-chamber that is open to the atmosphere, A positive pressure valve is provided between the main chamber and the sub-chamber and functions as a check valve that opens when the differential pressure of the main chamber relative to the sub-chamber exceeds a positive first threshold; A negative pressure valve is provided between the main chamber and the sub-chamber and functions as a check valve that opens when the differential pressure of the main chamber relative to the sub-chamber is less than a negative second threshold. A plate that is movable inside the main chamber, The plate is further equipped with a spring that biases it toward the first porous body, The positive pressure valve and the negative pressure valve are provided on the plate. A canister characterized by the following features.

2. Multiple positive pressure valves and negative pressure valves are provided. The canister according to claim 1, characterized in that

3. The main chamber has a tank port that communicates with the fuel tank and a purge port that communicates with the intake system. The tank port and the purge port are positioned below the first porous body. The positive pressure valve and the negative pressure valve are positioned above the first porous body. A canister according to claim 1 or 2, characterized in that it is a canister according to claim 1 or 2.

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