JP2008291809A - Fuel storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel storage device capable of reducing the quantity of evaporated fuel discharged from the fuel storage device, in the fuel storage device for storing fuel. <P>SOLUTION: This fuel storage device 1 storing the fuel F has a storage tank 12 having a first inside space 2 sealed for storing the fuel, a vessel 3 arranged upward in the first inside space and having a sealed second inside space 5, a reducing means for reducing the concentration of the evaporated fuel of the second inside space more than the concentration of evaporated fuel outside of the vessel in the first inside space, and discharge means 22 and 35 discharging the evaporated fuel of the fuel stored in the first inside space to an external part of the fuel storage device via the second inside space. The reducing means has opening-closing means 11, 22, 35 and 41 for communicating or cutting off the second inside space and a space outside of the vessel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel storage device, and more particularly to a fuel storage device that can reduce the amount of evaporated fuel discharged from the fuel storage device.

  In a fuel tank (fuel storage device) that stores fuel, the fuel is vaporized and vaporized fuel (vapor) is generated. The amount of vapor generated varies depending on the temperature, and the amount of vapor generated increases as the temperature of the fuel increases. For this reason, when the temperature of the fuel rises when the temperature rises during the daytime, a large amount of vapor is generated in the fuel tank.

  For example, an internal combustion engine is equipped with an evaporative fuel processing device that processes vapor generated in a fuel tank without releasing it into the atmosphere. This evaporative fuel processing apparatus has a canister that collects vapor from the fuel tank, and once adsorbs the vapor to the adsorbent inside the canister. During operation of the internal combustion engine, the fuel component (for example, HC) in the vapor collected in the canister is purged into the intake passage through the purge passage and processed using the intake negative pressure generated in the intake passage.

  When vapor is discharged from the fuel tank, it is not desirable that the amount of discharged vapor be a large value. For example, when an evaporative fuel processing apparatus is mounted, it is necessary to provide a larger capacity canister as the amount of vapor discharged increases. In addition, the larger the amount of vapor discharged, the greater the amount of vapor purged, which greatly affects the combustion of the internal combustion engine.

  Japanese Unexamined Patent Publication No. 2000-234573 (Patent Document 1) discloses a fuel tank that reduces the amount of fuel vapor flowing from the fuel tank to the charcoal canister, thereby reducing the size and cost of the canister.

  In the fuel tank described in Patent Document 1, a small-capacity sub chamber is formed in the fuel tank by a partition plate so that fuel is supplied to the sub chamber through the oil supply passage, and connected to the canister. The entrance to the steam passage is opened in the upper space of the sub chamber. Since the relatively low temperature fuel that has just been supplied is stored in the sub chamber, the gas portion containing the fuel vapor that is led from the main chamber or the like to the canister via the vapor passage always passes through the sub chamber, It is said that the fuel vapor is cooled and liquefied in the sub chamber, and the air flowing to the canister is only air containing almost no fuel vapor. In addition, another cooling means can also be provided in the sub chamber.

JP 2000-234573 A JP 2005-233086 A JP-A-5-262146 JP 2000-45889 A Japanese Patent Laid-Open No. 10-184476

  In the past, sufficient studies have not been made to reduce the amount of evaporated fuel discharged in a fuel storage device that stores fuel.

  An object of the present invention is to provide a fuel storage device that can reduce the amount of evaporated fuel discharged from the fuel storage device in a fuel storage device that stores fuel.

  The fuel storage device of the present invention is a fuel storage device that stores fuel, and is provided above the storage tank having a sealed first internal space for storing the fuel, and the first internal space. And the concentration of the evaporated fuel in the sealed second internal space and the second internal space is reduced compared to the concentration of the evaporated fuel outside the container in the first internal space. A reduction means; and a discharge means for discharging the evaporated fuel of the fuel stored in the first internal space to the outside of the fuel storage device via the second internal space, the reduction means comprising: And an opening / closing means for communicating or blocking the second internal space and the space outside the container.

  In the fuel storage device of the present invention, the opening / closing means includes first opening / closing means for opening / closing a bottom opening which is an opening provided in the bottom of the container, and the opening / closing control of the first opening / closing means includes It is performed based on at least one of the temperature in the fuel storage device and the position of the liquid level of the fuel stored outside the container in the first internal space.

  In the fuel storage device of the present invention, the opening / closing means may cause the evaporated fuel in the second internal space to flow based on a differential pressure between the inside of the container and the outside of the container in the first internal space. It has the 2nd opening-and-closing means discharged | emitted outside the said container in 1st interior space, It is characterized by the above-mentioned.

  In the fuel storage device of the present invention, the opening / closing means includes third opening / closing means for communicating the outside of the fuel storage device and the second internal space to introduce outside air into the second internal space. It is characterized by that.

  In the fuel storage device of the present invention, the discharge of the evaporated fuel by the discharge means is suppressed during a predetermined period.

  In the fuel storage device of the present invention, the predetermined period includes a period in which the fuel is not supplied to the fuel storage device.

  In the fuel storage device of the present invention, the container is configured to be able to store a part of the fuel stored in the first internal space when the container is opened by the opening / closing means. To do.

  According to the fuel storage device of the present invention, the amount of evaporated fuel discharged from the fuel storage device can be reduced.

  Hereinafter, an embodiment of the fuel storage device of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The first embodiment will be described with reference to FIGS. 1 to 5. The present embodiment relates to a fuel storage device that can reduce the amount of evaporated fuel discharged from the fuel storage device.

  In this embodiment, the fuel tank (fuel storage device, see reference numeral 1 in FIG. 1) has a main tank (storage tank, see reference numeral 12 in FIG. 1) that stores fuel. The main tank 12 has a sealed internal space for storing fuel ((first internal space), hereinafter referred to as a main space, reference numeral 2 in FIG. 1). A sub tank (container, see reference numeral 3 in FIG. 1) is provided above the main space 2. In the present embodiment, the main space 2 is a space excluding the internal space of the sub tank 3 (second internal space, see 5 in FIG. 1) inside the main tank 12.

  The sub tank 3 is provided with opening / closing means (reference numerals 11, 22, 41, and 35 in FIG. 1) for communicating or blocking the internal space 5 of the sub tank 3 and the space outside the sub tank 3. In this embodiment, in order to reduce the amount of vapor (evaporated fuel) generated in the main space 2, the opening / closing means is closed and the sub tank 3 is sealed. By sealing the sub tank 3, the vapor of the main space 2 is suppressed from entering the internal space 5 of the sub tank 3. In other words, the space in the main tank 12 that is in contact with the fuel liquid surface and in which the vapor can diffuse (hereinafter referred to as the vapor space) is limited to the gas portion in the main space 2. In this case, the volume of the vapor space is reduced by the volume of the sub tank 3 compared to the case where the sub tank 3 is not sealed. As a result, the amount of vapor generated in the main space 2 is reduced.

  Further, in order to reduce the amount of vapor discharged, the vapor in the main space 2 is discharged to the outside of the fuel tank 1 through the internal space 5 of the sub tank 3. As will be described later, the vapor concentration in the internal space 5 of the sub-tank 3 is made lower than the vapor concentration in the main space 2 by opening / closing control of the opening / closing means. For example, as a means for reducing the vapor concentration, liquid fuel in the internal space 5 of the sub tank 3 is discharged into the main space 2 by a thermo valve (first opening / closing means, see reference numeral 41 in FIG. 1) described later.

  The thermo valve 41 is provided at the bottom of the sub tank 3 and opens when the temperature in the fuel tank 1 becomes low. When fuel generated by liquefaction of vapor or the like exists in the sub-tank 3 in the cold state, the fuel is discharged to the main space 2 through the thermo valve 41. When the temperature in the fuel tank 1 rises, the thermo valve 41 is closed again. Thereby, the internal space 5 of the sub tank 3 can be sealed in a state in which liquid fuel is not substantially present. In the internal space 5 of the sub-tank 3, fuel vaporization does not occur, so that the vapor concentration is kept lean compared to the main space 2. As the vapor in the main space 2 is discharged through the internal space 5 of the sub-tank 3 having a low vapor concentration, the vapor is discharged as compared with the case where the vapor is discharged directly from the main space 2 to the outside of the fuel tank 1. The amount is reduced.

  FIG. 1 is a schematic configuration diagram of an apparatus according to the present embodiment. In FIG. 1, the code | symbol 1 shows a fuel tank (fuel storage apparatus). The fuel tank 1 includes a main tank 12 having a sealed internal space (first internal space (main space)) 2 for storing the fuel F. A fuel injection pipe 14 is connected to the main tank 12. Fuel F is injected into the main tank 12 through the fuel injection pipe 14. A fuel cap 15 is provided at the upper end opening of the fuel injection pipe 14.

  A feed pump 13 is provided inside the main tank 12. The fuel F stored in the main tank 12 is pumped by a feed pump 13 to an internal combustion engine (not shown) through a fuel passage 16. A pressure regulator 17 is provided in the fuel passage 16. A fuel return passage 18 is connected to the pressure regulator 17. The pressure of the fuel F pumped by the feed pump 13 is adjusted by the pressure regulator 17. When the fuel pressure of the fuel F exceeds a predetermined pressure, the surplus fuel F is returned to the main tank 12 through the fuel return passage 18.

  Inside the main tank 12, a sub tank 3 configured to be hermetically sealed is provided. The sub tank 3 is provided at a position separated from the inner wall portion 12 a at the lower part of the main tank 12. The sub tank 3 has an outer wall 4 that seals the internal space (second internal space) 5 of the sub tank 3. The inside of the main tank 12 is partitioned into an internal space 5 of the sub tank 3 and a main space 2 by an outer wall 4 of the sub tank 3. In other words, the main space 2 is a space in the space inside the main tank 12 excluding the internal space 5 of the sub tank 3. The outer wall 4 has such a strength that the volume of the inner space 5 is kept substantially constant even when the pressure acting on the sub tank 3 fluctuates.

  An evaporated fuel discharge path 20 is connected to the sub tank 3. In the sub tank 3, the position where the evaporated fuel discharge path 20 is connected is set in the gas storage portion 5 a (the upper portion of the sub tank 3) in which the gas in the internal space 5 is stored. A gas including vapor in the internal space 5 of the sub tank 3 is discharged to the outside of the main tank 12 through the evaporated fuel discharge path 20.

  The sub tank 3 is provided so as to be positioned above the fuel liquid level when the position of the fuel liquid level is the predetermined first position H1. In the main tank 12, the larger the volume of the vapor space, the more fuel F is vaporized until the vapor concentration reaches the saturated concentration.

  In this embodiment, the volume of the steam space is reduced by sealing the sub tank 3. The first position H1 is set from the viewpoint of reducing the amount of vapor generated by reducing the volume of the steam space by the sub tank 3. For example, when the sub-tank 3 having the same volume is provided, when the sub-tank 3 is provided above the main space 2, the sub-tank 3 is below the fuel level compared to the case where it is provided below. Less chances of being submerged. Therefore, by providing the subtank 3 so that the installation range of the subtank 3 includes the upper part in the main space 2, the subtank 3 can increase the chances that the volume of the steam space can be reduced.

  The first position H1 can be set to an arbitrary position between the position of the fuel level when the main tank 12 is full and the inner wall portion 12a at the lower part of the main tank 12. The first position H1 can be set, for example, such that the sub tank 3 is positioned higher in the main tank 12. The volume of the sub tank 3 can be, for example, about half of the volume of the main tank 12. In this case, the first position H <b> 1 can be set, for example, at an intermediate portion in the vertical direction of the main tank 12.

  A canister 23 is connected to the evaporated fuel discharge path 20. A passage 26 is provided inside the canister 23. The evaporated fuel discharge passage 20 is connected to one end of the passage 26. An open passage 25 that opens the passage 26 to the atmosphere is provided at the other end of the passage 26. The passage 26 is provided with an adsorption portion 24 containing activated carbon or the like. The vapor in the gas passing through the passage 26 is adsorbed by the adsorption unit 24. The canister 23 is connected to an intake passage of an internal combustion engine (not shown). During operation of the internal combustion engine, the fuel component (for example, HC) in the vapor collected in the canister 23 is purged into the intake passage by using the intake negative pressure generated in the intake passage.

  A cut-off valve 21 and an ORVR valve (discharge means, third opening / closing means) 22 are provided at a connection portion between the evaporated fuel discharge path 20 and the sub tank 3. The cut-off valve 21 prevents the liquid fuel F from flowing into the evaporated fuel discharge path 20. The ORVR valve 22 is provided to prevent the vapor from being released from the fuel injection pipe 14 or the like to the atmosphere during fuel supply. The ORVR valve 22 opens and closes according to a differential pressure between the internal space 5 of the sub tank 3 and the evaporated fuel discharge path 20, for example. The ORVR valve 22 is configured to open when the pressure in the internal space 5 of the sub-tank 3 rises above a predetermined differential pressure compared to the pressure in the evaporated fuel discharge path 20.

  For example, when the fuel level rises during fuel supply, the pressure in the main space 2 rises. In this case, as will be described later, the gas in the main space 2 flows into the sub tank 3, and the pressure in the internal space 5 of the sub tank 3 increases with the pressure in the main space 2. The ORVR valve 22 is opened by the pressure increase in the internal space 5 of the sub tank 3. As a result, the gas including the vapor in the internal space 5 of the sub tank 3 flows out to the canister 23 through the evaporated fuel discharge path 20. Therefore, an increase in pressure in the main tank 12 is suppressed. As a result, the vapor in the main tank 12 is suppressed from being released to the atmosphere via the fuel injection pipe 14 and the like.

  On the other hand, when the pressure in the internal space 5 of the sub-tank 3 is reduced to a negative pressure, the ORVR valve 22 is opened, and the air flowing in from the open passage 25 of the canister 23 passes through the evaporated fuel discharge passage 20 to the internal space 5 of the sub-tank 3. To be introduced. Therefore, the pressure in the internal space 5 of the sub tank 3 is generally maintained at atmospheric pressure.

  The outer wall 4 of the sub tank 3 has a lower float valve (first opening / closing means) that communicates or blocks the internal space 5 and the main space 2 of the sub tank 3 according to the position (height) of the fuel level in the main tank 12. 11 is provided. The lower float valve 11 is provided in the lower part of the outer wall 4 of the sub tank 3. The outer wall 4 is provided with a pressure valve 35 that connects or blocks the internal space 5 of the sub tank 3 and the main space 2 according to the pressure of the main space 2. The pressure valve 35 functions as a discharge unit and a second opening / closing unit of the present embodiment. The pressure valve 35 is provided in the upper part of the outer wall 4. The outer wall 4 is provided with a thermo valve (first opening / closing means) 41 that communicates or blocks the internal space 5 of the sub tank 3 and the main space 2 in accordance with the temperature.

  First, the lower float valve 11 will be described. In the present embodiment, the fuel F can be stored in the subtank 3 by communicating the internal space 5 of the subtank 3 and the main space 2 during refueling, and the subtank 3 is sealed to reduce the volume of the vapor space when the fuel level is lowered. The lower float valve 11 is opened and closed so that it can be reduced.

  FIG. 2 is an enlarged view of the vicinity of the sub tank 3 in FIG. FIG. 2 shows a state where the lower float valve 11 is closed (fully closed). The lower float valve 11 is opened and closed according to the position of the fuel level of the fuel F. The lower float valve 11 includes a valve body 11a, a float 11b, and a rod 11c. The float 11b is configured to float on the fuel liquid level, and moves in the vertical direction as the fuel liquid level rises and falls. The lower opening (bottom opening) 11d provided on the outer wall 4 is opened and closed by the valve body 11a. The valve body 11a and the float 11b are connected by a rod 11c.

  When the fuel level rises and the float 11b moves upward from a predetermined second position H2, the rod 11c moves the valve body 11a upward (in the opening direction), as shown in FIG. The opening 11d is opened. When the fuel level is below the second position H2, as shown in FIG. 2, the valve body 11a closes the lower opening 11d (fully closed).

  As shown in FIG. 2, the lower opening 11 d is provided in the lower wall (bottom) 4 a of the outer wall 4. The lower wall portion 4a of the outer wall 4 is provided with an inclination that goes downward as it goes to the lower opening 11d, as indicated by reference numeral 4b. Thereby, as will be described later, the fuel F can be discharged to the main space 2 through the lower opening 11d without remaining in the sub tank 3.

  Next, the pressure valve 35 will be described. The pressure valve 35 opens and closes so that the pressure in the main space 2 is maintained at a value within a predetermined range.

  FIG. 4 is a view for explaining the operation when the pressure valve 35 is opened. For example, when the temperature rises during the day, vapor is generated by the fuel F being vaporized in the main space 2. Due to the generation of vapor, the pressure in the main space 2 increases. Further, as the gas in the main space 2 expands due to a temperature rise, the pressure in the main space 2 increases. When the pressure in the main space 2 increases and exceeds the maximum value in the predetermined range, the pressure valve 35 is opened. As a result, as indicated by reference numeral Y <b> 2 in FIG. 4, the gas including the vapor in the main space 2 flows into the internal space 5 of the sub tank 3. Since the pressure valve 35 is provided on the upper portion of the outer wall 4, the vapor in the main space 2 can be discharged into the internal space 5 of the sub tank 3 without any trouble even when the fuel level rises.

  On the other hand, when the temperature decreases or when the fuel level is decreased due to consumption of the fuel F, the pressure in the main space 2 decreases. When the pressure in the main space 2 decreases and is below the minimum value in the predetermined range, the pressure valve 35 is opened. In this case, a gas containing vapor flows from the sub tank 3 into the main space 2 as indicated by reference numeral Y1 in FIG. When the pressure in the main space 2 is a value within the predetermined range, the pressure valve 35 is closed and the main space 2 and the internal space 5 of the sub tank 3 are shut off. Although the pressure valve 35 is opened and closed according to the pressure in the main space 2, the pressure in the internal space 5 of the sub tank 3 is maintained substantially constant (atmospheric pressure). The pressure valve 35 is opened and closed based on the differential pressure with the internal space 5.

  FIG. 5 is a diagram illustrating an example of the pressure valve 35. The pressure valve 35 is used when gas flows from the main space 2 to the internal space 5 of the sub tank 3 (see reference Y3), compared to when gas flows from the internal space 5 of the sub tank 3 to the main space 2 (see reference Y4). , More gas can be circulated. This is due to the following reason.

  When fuel F is supplied to the main tank 12, the pressure in the main space 2 increases as the fuel level rises. While the fuel level is below the second position H2 (see FIG. 2), the lower float valve 11 is closed and the lower opening 11d remains closed. 5 is not communicated. Therefore, the pressure of the main space 2 is higher than that of the internal space 5 of the sub tank 3. In this case, the pressure valve 35 is opened, and the gas in the main space 2 flows into the sub-tank 3 (see symbol Y3). Here, at the time of fuel supply, the change rate of the volume (pressure) of the gas portion of the main space 2 is greater than when the temperature rises during the daytime. For this reason, in order to suppress the pressure increase in the main space 2, it is necessary to discharge a large amount of gas to the sub tank 3 through the pressure valve 35.

  For example, as shown in FIG. 5, the pressure valve 35 may include a reed valve 35a and a check valve 35b. The reed valve 35a is opened when the pressure in the main space 2 exceeds the maximum value in the predetermined range. On the other hand, the check valve 35b is opened when the pressure in the main space 2 is equal to or lower than the minimum value in the predetermined range. The reed valve 35a can be easily set to have a larger opening area than the check valve 35b. At the time of fuel supply, a large amount of gas can be quickly discharged from the main space 2 to the sub tank 3 by opening the reed valve 35a whose opening is set to a large value. Thereby, the pressure rise of the main space 2 at the time of fuel supply is suppressed. As a result, the vapor is suppressed from being discharged into the atmosphere from the fuel injection pipe 14 (FIG. 1) or the like.

  In the present embodiment, the second position H2 is set below the lower opening 11d. Thereby, according to the position of a fuel liquid level and the change of a position, there can exist an effect which is demonstrated below. The second position H2 can be set at a position slightly below the lower opening 11d, for example. The second position H2 can be, for example, the same position as the first position H1 (FIG. 1).

  First, the case where the fuel level is lowered from the second position H2 will be described. In this case, as described with reference to FIG. 2, the lower float valve 11 is closed (fully closed). Thereby, the internal space 5 and the main space 2 of the sub tank 3 are shut off. For this reason, the volume of the vapor space in the main tank 12 (FIG. 1) is the volume of the gas portion in the main space 2. Compared with the case where the sub tank 3 is not provided, the volume of the vapor space is reduced by an amount corresponding to the volume of the internal space 5 of the sub tank 3. For this reason, when the fuel F is vaporized, the concentration of the vapor generated by the vaporization of the fuel F becomes high at an early stage and reaches the saturated concentration at each temperature. Therefore, the amount of vapor generated in the main space 2 can be suppressed. By suppressing the vaporization of the fuel F, an increase in pressure in the main space 2 due to the generation of vapor is suppressed.

  By reducing the volume of the vapor space, even if the gas in the vapor space expands when the temperature rises during the daytime, the amount of expansion decreases. Therefore, an increase in pressure in the main space 2 is suppressed as compared with the case where the sub tank 3 is not provided. By suppressing the generation of vapor and pressure increase in the main space 2, the amount of vapor discharged from the fuel tank 1 is reduced.

  Next, a case where the fuel liquid level is above the second position H2 will be described. The second position H2 is set at a position below the lower opening 11d. Therefore, when the fuel level rises and reaches the lower opening 11d during refueling or the like, the lower float valve 11 is opened as shown in FIG. Therefore, the fuel F flows into the internal space 5 of the sub tank 3 from the lower opening 11d as the fuel level rises. The internal space 5 of the sub tank 3 is effectively used as a fuel F storage space. For this reason, the amount of fuel F that can be stored in the main tank 12 due to the provision of the sub tank 3 is suppressed.

  On the other hand, when the fuel level is lowered due to consumption of the fuel F, the fuel F in the sub tank 3 flows out from the lower opening 11d to the main space 2. As described above, the lower wall portion 4a of the outer wall 4 is provided with an inclination that is directed downward toward the lower opening portion 11d. Therefore, when the fuel level is lowered, the fuel F in the sub tank 3 can flow out of the lower opening 11d without remaining in the sub tank 3.

  After the fuel F flows out of the sub tank 3, when the fuel level is lowered to the height of the second position H2, the lower float valve 11 is closed. Since the fuel F has already flowed out, the lower float valve 11 can be closed in a state where the liquid fuel F does not substantially exist in the sub tank 3. Even if the temperature rises in this state, the fuel F is not vaporized in the sub-tank 3, so that vapor is not substantially generated. Accordingly, the internal space 5 of the sub tank 3 can be in a state where the vapor concentration is lower than that of the main space 2.

  When the pressure in the main space 2 rises when the temperature rises or the like, a gas containing vapor flows into the sub tank 3 from the main space 2 as indicated by a symbol Y2 in FIG. The vapor in the gas flowing into the internal space 5 of the sub tank 3 diffuses into the internal space 5 of the sub tank 3 having a relatively low vapor concentration. Therefore, the gas discharged to the evaporated fuel discharge path 20 is a gas having a lower vapor concentration than the gas flowing in from the main space 2. Therefore, the concentration of the vapor discharged into the evaporated fuel discharge path 20 is compared with the case where the gas containing vapor is discharged directly from the main space 2 to the evaporated fuel discharge path 20 without going through the inner space 5 of the sub tank 3. Can be reduced.

  It is possible to reduce the capacity of the canister 23 by reducing the concentration of the vapor discharged to the evaporated fuel discharge path 20. For example, when the volume of the sub tank 3 is substantially equal to the volume (maximum value) of the gas portion of the main space 2, the capacity of the canister 23 is almost halved compared to the case where the sub tank 3 is not provided. be able to. Further, the amount of fuel component purged into the intake passage of the internal combustion engine is reduced by reducing the concentration of the vapor discharged to the evaporated fuel discharge passage 20. For this reason, when the fuel component is purged, the influence on the air-fuel ratio control of the internal combustion engine can be reduced.

  When a gas containing a relatively high concentration of vapor flows from the main space 2, the vapor concentration in the internal space 5 of the sub tank 3 increases. If the high-concentration vapor is confined in the sub tank 3, the amount of vapor discharged to the evaporated fuel discharge path 20 will increase. In the present embodiment, the thermo valve 41 returns the vapor flowing into the sub tank 3 and the fuel F generated by the liquefaction of the vapor to the main space 2.

  As shown in FIG. 1, the thermo valve 41 opens and closes a second lower opening (bottom opening) 41 a provided in a lowermost portion of the lower wall 4 a of the outer wall 4 of the sub tank 3. For example, the second lower opening 41a is provided at substantially the same position as the lower opening 11d.

  The thermo valve 41 opens when the temperature in the main tank 12 is equal to or lower than a predetermined temperature, and closes when the temperature exceeds the predetermined temperature. The predetermined temperature can be set to room temperature, for example.

  When the thermo valve 41 is opened when the temperature is equal to or lower than the predetermined temperature, for example, when the vapor condenses and liquefies in the sub-tank 3 in the cold state, the liquefied fuel F enters the main space 2 via the thermo valve 41. Discharged. For this reason, when the temperature rises and the thermo valve 41 is closed, a state in which substantially no liquid fuel F is present in the sub tank 3 is realized. Therefore, even if the temperature rises thereafter, no new vapor is generated due to vaporization, so the amount of vapor in the sub tank 3 does not increase. Thereby, an increase in the vapor concentration in the sub tank 3 is suppressed, and the vapor concentration is suppressed to a lower concentration than in the main space 2. Further, when the thermo valve 41 is closed, a gas having a lean vapor concentration when cold is trapped in the sub tank 3. Therefore, the amount of vapor discharged to the evaporated fuel discharge path 20 is more reliably reduced.

  According to the present embodiment, the volume of the vapor space is reduced by sealing the sub tank 3 when the fuel liquid level is lower than the second position H2. Thereby, the amount of vapor generated in the main space 2 is reduced. Further, since the sub tank 3 is sealed in a state where the fuel F does not substantially exist in the sub tank 3, no vapor is generated in the sub tank 3 due to the vaporization of the fuel F. Therefore, the amount of vapor generated in the entire main tank 12 can be reduced. As a result, the amount of vapor discharged from the fuel tank 1 is reduced.

  The gas including the vapor in the main space 2 is discharged to the evaporated fuel discharge path 20 through the internal space 5 of the sub tank 3. In the internal space 5 of the sub tank 3, no vapor is generated due to the vaporization of the fuel F, and therefore the vapor concentration is lower than that in the main space 2. For this reason, the vapor | steam discharge amount reduces compared with the case where gas is discharged | emitted from the main space 2 directly to the evaporative fuel discharge path 20 by the gas containing vapor | steam being discharged | emitted via the internal space 5 of the sub tank 3. FIG. Can be done.

(Second Embodiment)
A second embodiment will be described with reference to FIGS. In the second embodiment, only differences from the first embodiment will be described.

  In the first embodiment (FIG. 1), the gas containing the vapor generated in the main space 2 is always discharged via the internal space 5 of the sub tank 3 in which the vapor concentration is kept relatively low. In this case, the effect of reducing the amount of vapor discharged can be continuously obtained. In the present embodiment, there is a limit on the discharge of vapor through the internal space 5 of the sub tank 3. The vapor discharge through the internal space 5 of the sub tank 3 is controlled so as to reduce the vapor discharge amount during refueling, which tends to increase the vapor discharge amount.

  By limiting the discharge of vapor through the internal space 5 of the sub-tank 3 when the amount of vapor discharged (generated amount) is relatively small, the internal space 5 of the sub-tank 3 can be reduced as compared with the case of no restriction. It becomes possible to make the vapor concentration lower. When the amount of vapor discharged is likely to increase (during refueling), the amount of vapor discharged can be more reliably reduced by using the gas in the internal space 5 of the sub-tank 3 in which the vapor concentration is kept low. It becomes possible.

  In the present embodiment, the gas flow from the main space 2 into the sub tank 3 is blocked. The gas containing vapor generated in the main space 2 is discharged toward a main canister (see reference numeral 60 in FIG. 6) connected to the main space 2. Thereby, the vapor is suppressed from flowing into the sub tank 3, and the vapor concentration in the sub tank 3 is suppressed to a low concentration. At the time of fuel supply, the gas in the sub tank 3 is discharged to the canister 23 connected to the sub tank 3 (see symbol Y10 in FIG. 9). Since the gas discharged to the canister 23 has a lean vapor concentration, the amount of vapor discharged during fuel supply can be reduced.

  FIG. 6 is a schematic configuration diagram of an apparatus according to the present embodiment. Instead of the cut-off valve 21 and the ORVR valve 22 of the first embodiment (FIG. 1), a discharge path differential pressure valve (third opening / closing means) 33 and an oil supply valve 34 are provided. The discharge path differential pressure valve 33 opens when the pressure in the inner space 5 of the sub tank 3 becomes lower than the pressure in the evaporated fuel discharge path 20, and the pressure in the inner space 5 in the sub tank 3 changes to the pressure in the evaporated fuel discharge path 20. Close if above. Thereby, the atmosphere is introduced into the sub tank 3 when the internal space 5 of the sub tank 3 becomes negative pressure.

  The refueling valve 34 regulates the flow of gas from the internal space 5 of the sub tank 3 toward the canister 23 during periods other than the time of fuel refueling, and communicates the internal space 5 of the sub tank 3 and the evaporated fuel discharge path 20 during fuel refueling. Let Thereby, at the time of fuel supply, the gas in the sub tank 3 is discharged from the internal space 5 of the sub tank 3, which has become relatively high pressure due to the inflow of the fuel F, to the evaporated fuel discharge path 20. A conventionally known method can be used as a method for detecting fuel supply. For example, when opening of a lid opener (not shown) is detected, or when it is within a predetermined time after detection of opening of a lid opener, it can be determined that fuel is being supplied.

  The main space 2 is connected to a main-side evaporated fuel discharge passage 43 for discharging the gas in the main space 2 to the outside of the main tank 12 without passing through the internal space 5 of the sub tank 3. The main-side evaporated fuel discharge passage 43 is connected to the main-side gas storage portion 2a in which the gas in the main space 2 is stored. A main side canister 60 is provided in the main side evaporated fuel discharge passage 43. The main canister 60 can be similar to the canister 23. Vapor contained in the gas discharged from the main space 2 is adsorbed by the main canister 60. A cut-off valve 31 and an ORVR valve 32 are connected to a connection portion between the main-side evaporated fuel discharge passage 43 and the main space 2. The cut-off valve 31 and the ORVR valve 32 can be the same as the cut-off valve 21 and the ORVR valve 22 of the first embodiment, respectively.

  Instead of the pressure valve 35 of the first embodiment, a pressure valve (second opening / closing means) 36 is provided. The pressure valve 36 opens and closes based on the pressure in the internal space 5 of the sub tank 3. The pressure valve 36 is opened when the pressure in the internal space 5 of the sub tank 3 exceeds a predetermined pressure. The predetermined pressure can be set to a value equal to or higher than atmospheric pressure, for example. On the other hand, the pressure valve 36 is closed when the pressure in the internal space 5 of the sub tank 3 is equal to or lower than the predetermined pressure. In the present embodiment, since the main space 2 is maintained at a substantially constant pressure (atmospheric pressure), the pressure valve 36 is opened and closed based on the differential pressure between the main space 2 and the internal space 5 of the sub tank 3. . The sub tank 3 is not provided with a thermo valve 41.

  FIG. 7 is a diagram illustrating an operation when the pressure in the main tank 12 decreases in the main tank 12 in a state where the fuel liquid level is lower than the second position H2. Since the fuel level is lower than the second position H2, the lower float valve 11 is closed (fully closed). When the pressure in the main tank 12 decreases due to a temperature drop or the like, the atmosphere is introduced into the main space 2 through the main canister 60 as indicated by reference numeral Y5, and the canister 23 as indicated by reference numeral Y6. The atmosphere is introduced into the internal space 5 of the sub tank 3 via the. Thereby, it is suppressed that the pressure of the main space 2 and the internal space 5 of the sub tank 3 falls.

  FIG. 8 is a diagram illustrating an operation when the pressure in the main tank 12 increases in the main tank 12 in a state where the fuel liquid level is lower than the second position H2. When the pressure in the main space 2 and the internal space 5 of the sub-tank 3 rises during daytime temperature rises (except when fueling), the gas in the main space 2 discharges the main-side evaporated fuel as indicated by reference numeral Y7. It is discharged to the path 43. On the other hand, since the exhaust pressure differential valve 33 and the oil supply valve 34 are closed, the gas in the internal space 5 of the sub tank 3 is not exhausted to the evaporated fuel exhaust path 20. When the pressure in the internal space 5 of the sub tank 3 exceeds the predetermined pressure, the pressure valve 36 is opened. As a result, the gas in the sub tank 3 is discharged into the main space 2 as indicated by reference numeral Y8.

  7 and 8, when the lower float valve 11 is closed (fully closed), the volume of the vapor space is reduced by an amount corresponding to the volume of the internal space 5 of the sub tank 3. Therefore, the amount of vapor generated in the main space 2 is suppressed as in the first embodiment. Therefore, the amount of vapor discharged from the main tank 12 is reduced as compared with the case where the sub tank 3 is not provided.

  FIG. 9 is a diagram illustrating an operation during fuel supply. When the fuel level is higher than the second position H2 during fuel supply, the lower float valve 11 is opened. In this case, the fuel F flows into the sub tank 3 through the lower float valve 11 as indicated by reference numeral Y11. When the pressure in the internal space 5 of the sub tank 3 rises as the fuel level rises, the gas in the sub tank 3 evaporates as shown by reference numeral Y10 through the fuel supply valve 34 that is opened when fuel is supplied. It is discharged to the fuel discharge path 20. The vapor contained in the gas discharged to the evaporated fuel discharge path 20 is adsorbed by the canister 23. Further, when the pressure in the main space 2 increases as the fuel level rises, the gas in the main space 2 is discharged to the main-side evaporated fuel discharge passage 43 as indicated by reference numeral Y9. Note that a part of the gas in the main space 2 may be discharged to the evaporated fuel discharge path 20 via the internal space 5 of the sub tank 3 when fuel is supplied.

  FIG. 10 is a diagram mainly showing the state of gas entering and exiting the sub-tank 3 with respect to the contents described with reference to FIGS. 7 and 8. As indicated by reference numeral Y <b> 12 in FIG. 10, the air is introduced into the sub tank 3 when the pressure in the internal space 5 of the sub tank 3 decreases. On the other hand, when the pressure in the internal space 5 of the sub-tank 3 rises as indicated by the symbol Y13, the gas containing the vapor in the sub-tank 3 is discharged to the main space 2. Thus, the vapor concentration in the sub-tank 3 decreases by repeatedly introducing the atmosphere (Y 12) and discharging the gas (vapor) (Y 13) to the main space 2 in the sub-tank 3. At the time of fuel supply, the gas in the sub tank 3 is discharged toward the canister 23 as indicated by reference numeral Y10 in FIG. In this case, since the vapor concentration in the sub tank 3 is low, the amount of vapor discharged can be made small.

  When the atmosphere is introduced into the sub tank 3 (see symbol Y12 in FIG. 10), the fuel component adsorbed by the canister 23 is back purged into the sub tank 3 together with the atmosphere, so that the vapor concentration in the sub tank 3 is There is a possibility that it will rise temporarily. However, in this embodiment, the gas containing vapor is discharged to the canister 23 only when fuel is supplied (see FIG. 9). Therefore, the fuel component adsorbed on the canister 23 can be a small amount as compared with the case where the gas containing vapor is discharged not only at the time of fuel supply. For this reason, the fuel component adsorbed by the canister 23 can be sufficiently reduced as the introduction of the atmosphere into the sub tank 3 is repeated between the fuel supply and the next fuel supply.

  Further, the fuel component back purged into the sub tank 3 is discharged to the main space 2 through the pressure valve 36 when the pressure rises. Therefore, even if the vapor concentration in the sub-tank 3 temporarily increases immediately after fuel supply, the vapor concentration in the sub-tank 3 can be sufficiently reduced before the next fuel supply.

  FIG. 11 is a diagram illustrating an operation when the fuel liquid level is equal to or higher than the second position H2 (except when fuel is supplied). When the fuel level is equal to or higher than the second position H2, the lower float valve 11 is open. For this reason, when the fuel level decreases with the consumption of the fuel F, the fuel F can flow out from the sub-tank 3 to the main space 2 through the lower float valve 11 as indicated by reference numeral Y14.

  While the fuel F exists in the sub tank 3, vapor is generated in the sub tank 3 due to vaporization of the fuel F. When the temperature rises during the day, the gas containing the vapor in the sub-tank 3 is discharged from the sub-tank 3 to the main space 2 as indicated by reference numeral Y15. Therefore, the amount of vapor discharged to the main-side canister 60 is a large value. It is possible to become. However, when the fuel liquid level is equal to or higher than the second position H2, the volume of the vapor space is a small value, so the amount of vapor generated itself is a small value. Therefore, the amount of vapor discharged to the main canister 60 can be suppressed to a small amount, as in the state where the fuel liquid level is lower than the second position H2.

It is a schematic block diagram of the apparatus which concerns on 1st Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of the fuel liquid level fall of 1st Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of the fuel liquid level raise of 1st Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of valve opening of the pressure valve in 1st Embodiment of the fuel storage apparatus of this invention. It is a figure which shows an example of the pressure valve of 1st Embodiment of the fuel storage apparatus of this invention. It is a schematic block diagram of the apparatus which concerns on 2nd Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of the pressure fall of 2nd Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of the pressure rise of 2nd Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of fuel supply of 2nd Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the flow of the gas of 2nd Embodiment of the fuel storage apparatus of this invention. It is a figure for demonstrating the operation | movement at the time of the fuel level raise of 2nd Embodiment of the fuel storage apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Main space 3 Sub tank 4 Outer wall 4a Lower wall part 5 Internal space 11 Lower float valve 11a Valve body 11b Float 11c Rod 11d Lower opening part 12 Main tank 13 Feed pump 14 Fuel injection pipe 15 Fuel cap 16 Fuel passage 17 Pressure Regulator 18 Fuel return passage 20 Evaporative fuel discharge passage 21 Cut-off valve 22 ORVR valve 23 Canister 24 Adsorption part 25 Open passage 26 Passage 31 Cut-off valve 32 ORVR valve 33 Drain pressure differential valve 34 Oil supply valve 35 Pressure valve 36 Pressure valve 41 Thermo valve 43 Main side evaporative fuel discharge path 60 Main side canister

Claims (7)

A fuel storage device for storing fuel,
A storage tank having a sealed first internal space for storing the fuel;
A container provided above the first internal space and having a sealed second internal space;
Reducing means for reducing the concentration of the evaporated fuel in the second internal space compared to the concentration of the evaporated fuel outside the container in the first internal space;
Discharging means for discharging the evaporated fuel of the fuel stored in the first internal space to the outside of the fuel storage device via the second internal space;
The fuel storage device, wherein the reducing means has an opening / closing means for communicating or blocking the second internal space and a space outside the container. The fuel storage device according to claim 1,
The opening / closing means has first opening / closing means for opening / closing a bottom opening which is an opening provided in a bottom of the container,
The opening / closing control of the first opening / closing means is performed based on at least one of the temperature in the fuel storage device and the position of the liquid level of the fuel stored outside the container in the first internal space. A fuel storage device characterized by that. The fuel storage device according to claim 1 or 2,
The opening / closing means converts the evaporated fuel in the second internal space into the container in the first internal space based on a differential pressure between the inside of the container and the outside of the container in the first internal space. A fuel storage device, comprising: a second opening / closing means for discharging to the outside. The fuel storage device according to any one of claims 1 to 3,
The fuel storage device, wherein the opening / closing means has third opening / closing means for communicating outside of the fuel storage device and the second internal space to introduce outside air into the second internal space. . The fuel storage device according to any one of claims 1 to 4,
The fuel storage device, wherein the discharge of the evaporated fuel by the discharge means is suppressed during a predetermined period. The fuel storage device according to claim 5, wherein
The predetermined period includes a period in which the fuel is not supplied to the fuel storage device. The fuel storage device according to any one of claims 1 to 6,
The fuel storage device, wherein the container is configured to be able to store a part of the fuel stored in the first internal space when the container is opened by the opening / closing means.

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