JP2006193127A - Fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel tank, capable of restricting generation quantity of fuel vapor by favorably contracting a tank main body when fuel in the tank main body is reduced. <P>SOLUTION: The fuel tank 10 comprises the tank main body 12 that is formed to be capable of expanding/contracting in accordance with residual quantity of fuel 17 stored in the tank main body 12, and a tank contracting means 20 to contract the tank main body 12 in accordance with reduction quantity of the fuel 17. The tank contracting means 20 is provided with a communication passage 21 communicated with the inside of the tank main body 12, a vacuum pump 22 provided in the communication passage 21, and a residual quantity detection part 23 to detect the residual quantity of fuel 17 in the tank main body 12. It is also provided with a control part 24 to drive the vacuum pump 22 based on a detection signal when reduction of fuel 17 is detected by the residual quantity detection part 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel tank, and more particularly to a fuel tank that changes the capacity of a tank body in accordance with the remaining amount of fuel stored in the tank body.

2. Description of the Related Art As a fuel tank for an automobile or the like, there is known a fuel tank that expands as the fuel increases and contracts as the fuel decreases (see, for example, Patent Document 1).
JP-A-11-245671

The fuel tank of Patent Document 1 is formed by deforming a tank body that stores fuel with a deformable membrane wall.
According to this fuel tank, when the fuel in the tank body increases, the tank body expands by pressing the tank body outward with the increased fuel.

On the other hand, when the fuel in the tank main body decreases, the pressing force to the tank main body by the fuel is eliminated, and the tank main body contracts due to the restoring force of the tank main body.
Thus, by expanding and contracting the tank body in accordance with the increase or decrease of the fuel, the space above the fuel level in the tank body is reduced, and the amount of fuel vapor generated in the fuel tank is suppressed.

However, when the fuel in the tank main body decreases, the tank main body is contracted only by the restoring force of the tank main body, so that there is a possibility that the tank main body cannot be contracted appropriately.
If the tank body does not shrink properly when the fuel is reduced, the space above the fuel level in the tank body becomes large, and the amount of fuel vapor generated in the fuel tank cannot be suppressed.

  An object of the present invention is to provide a fuel tank capable of suppressing the generation amount of fuel vapor by suitably contracting the tank body when the fuel in the tank body decreases.

  The invention according to claim 1 includes a tank body that stores fuel to be supplied to the engine, and the tank body can be expanded and contracted in order to change the capacity of the tank body according to the remaining amount of fuel stored in the tank body. The formed fuel tank is provided with a tank reduction means for reducing the tank body in accordance with the amount of fuel reduction when the fuel in the tank body is reduced.

By providing the tank reducing means, it is possible to suitably reduce the tank main body by the tank reducing means when the fuel in the tank main body decreases.
By suitably reducing the tank body according to the amount of fuel reduction, the space above the fuel level in the tank body can be reduced favorably.

  In the invention according to claim 2, the tank reducing means includes a vacuum pump communicating with the inside of the tank main body, and further includes a remaining amount detecting unit that detects the remaining amount of fuel in the tank main body. When a fuel decrease is detected, a control unit that drives a vacuum pump based on a detection signal is provided, and by driving the vacuum pump, the tank body is reduced to a negative pressure state. Features.

A vacuum pump was used as means for reducing the tank. This vacuum pump is communicated with the tank body via a communication passage.
The communication passage can be bent in a relatively arbitrary direction, and the examination time when determining the mounting position of the vacuum pump can be shortened.

  In the invention according to claim 3, the tank contracting means includes a communication passage that connects the tank body and the intake passage of the engine, and the communication passage includes an on-off valve that opens when the fuel decreases. When the on-off valve is opened, a negative pressure in the intake passage is used to reduce the tank main body to a negative pressure in the tank main body.

An intake passage was used as a means for reducing the tank. The intake passage is provided in a normal automobile.
By using this intake passage, the configuration of the tank reducing means can be simplified.

  5. The invention according to claim 4, wherein the tank contracting means stores the fuel vapor generated in the tank main body, and stores the stored fuel vapor together with outside air taken in from the outside air introduction passage through the intake passage of the engine. When the outside air introduction passage is provided with an open / close valve and a remaining amount detecting unit for detecting the remaining amount of fuel in the tank body, when the remaining amount detecting unit detects a decrease in fuel And a controller for closing the on-off valve based on the detection signal, and using the negative pressure in the intake passage when the on-off valve is closed, the tank main body is reduced to a negative pressure state. It is characterized by doing.

A canister was used as a means for reducing the tank. The canister is provided in a normal automobile.
By using this canister, the configuration of the tank reducing means can be simplified.

  In the invention according to claim 5, the tank contracting means includes a weight member at an upper portion of the tank main body, and includes an on-off valve that opens and closes the tank main body. When the fuel in the tank main body decreases, the tank reducing means By opening, the tank body is reduced by the weight member.

  A weight member was used as the tank reducing means. By adopting a simple configuration in which the weight member is simply provided on the upper portion of the tank body, the cost of the tank reducing means can be suppressed.

  In the invention according to claim 6, the tank reducing means includes a spring member that presses the tank main body in a direction to reduce the tank main body, an open / close valve that opens and closes the tank main body, and when the fuel in the tank main body decreases, By opening the on-off valve, the tank body is reduced by the spring member.

  A spring member was used as the tank reducing means. The spring member is a lighter member than the weight member and can reduce the vehicle weight.

  In the fuel tank according to the present invention, there is an advantage that the generation amount of fuel vapor in the fuel tank can be surely suppressed by favorably reducing the space above the fuel liquid level in the tank body.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a sectional view showing a first embodiment of a fuel tank according to the present invention.
The fuel tank 10 houses a tank body 12 inside an exterior tank 11, and communicates a lower end portion of a filler pipe (not shown) into the tank body 12, and the upper end portion of the filler pipe is located above the exterior tank 11. The tank body 12 is provided with a tank reducing means 20.

The tank body 12 is a container that forms a space 16 by connecting the ceiling portion 13 and the bottom portion 14 with a peripheral wall 15, and stores the fuel 17 supplied to the engine 46 (see FIG. 3) in the space 16.
The peripheral wall 15 has a central portion 15a formed in an accordion shape and is a wall portion that can be expanded and contracted. The space 16 of the tank body 12, that is, the capacity of the tank body 12 can be changed by expanding and contracting the bellows-shaped central portion 15a.

  The filler pipe is a fuel supply pipe for supplying the fuel 17 into the tank body 12 from the opening at the upper end.

  The tank contracting means 20 includes a communication passage 21 communicating with the inside of the tank body 12, a vacuum pump 22 is provided in the communication passage 21, and a remaining amount detection unit 23 that detects the remaining amount of the fuel 17 in the tank body 12. When the remaining amount detection unit 23 detects a decrease in the fuel 17, a control unit 24 that drives the vacuum pump 22 based on the detection signal is provided.

The vacuum pump 22 is a pump that communicates with the tank body 12 via the communication passage 21 and removes air and fuel vapor in the tank body 12 to make the tank body 12 have a negative pressure.
The communication passage 21 can be bent in a relatively arbitrary direction, and the examination time when determining the mounting position of the vacuum pump 22 can be shortened.
Note that the negative pressure refers to a pressure from the atmospheric pressure to zero (absolute vacuum).

The remaining amount detection unit 23 is a float arm type in which a base end portion 28 a of an arm 28 is rotatably provided in the detection unit main body 26 and a float 29 is provided in a distal end portion 28 a of the arm 28.
The remaining amount detection unit 23 detects the fuel 17 in the tank main body 12 by detecting the swing movement amount of the arm 28 by the detection unit main body 26 when the arm 28 swings about the base end portion 28a. The detection signal is transmitted to the control unit 24.
The float 29 is a floating body that is held in a state of floating on the fuel surface 17 a by the buoyancy of the fuel 17.

  The control unit 24 confirms the decrease in the fuel 17 based on the detection signal sent from the remaining amount detection unit 23, and transmits a drive signal to the vacuum pump 22 when confirming the decrease in the fuel 17.

Next, the operation of the fuel tank 10 will be described with reference to FIG.
FIGS. 2A and 2B are views for explaining an example of contracting the fuel tank according to the first embodiment.
In (a), the fuel 17 in the tank main body 12 decreases, and the fuel surface 17a descends in a direction away from the ceiling portion 13.

As the fuel surface 17a descends, the float 29 descends, and the arm 28 swings downward about the base end 28a.
Based on the detection signal sent from the remaining amount detection unit 23, the control unit 24 detects that the arm 28 swings downward, that is, the fuel 17 has decreased.

When the decrease in the fuel 17 is detected, a drive signal is transmitted from the control unit 24 to the vacuum pump 22.
When the vacuum pump 22 is driven, air or fuel vapor in the tank body 12 is sucked into the communication passage 21 as indicated by an arrow A and removed from the tank body 12.
By removing the air and fuel vapor in the tank body 12, the tank body 12 is brought into a negative pressure state.

In (b), the space 16 in the tank body 12, that is, the space 16 above the fuel liquid level 17 a is brought into a negative pressure state by the tank reducing means 20, so that the peripheral wall 15 of the tank body 12 (specifically, the bellows shape). The central part 15a) of the slag shrinks.
The ceiling 13 of the tank main body 12 is lowered, and the tank main body 12 is suitably reduced.

  As the ceiling portion 13 of the tank body 12 descends, the base end portion 28a of the arm 28 approaches the fuel surface 17a. The arm 28 swings around the base end portion 28a, and the inclination angle θ of the arm 28 increases.

  Based on the detection signal sent from the remaining amount detection unit 23, the control unit 24 detects that the ceiling 13 has approached the fuel surface 17 a and transmits a stop signal to the vacuum pump 22. When the vacuum pump 22 is stopped, the contraction of the tank body 12 is stopped.

As described above, according to the fuel tank 10 of the first embodiment, the tank main body 12 is suitably reduced in accordance with the remaining amount of the fuel 17 stored in the tank main body 12, so that the fuel tank 17 is located above the fuel liquid level 17a. The space 16 can be reduced favorably.
Thereby, the generation amount of the fuel vapor in the fuel tank 12 can be reliably suppressed.

  Next, second to fifth embodiments will be described with reference to FIGS. In the second to fifth embodiments, the same reference numerals are assigned to the same similar members as those of the fuel tank 10 of the first embodiment, and the description thereof is omitted.

Second Embodiment FIG. 3 is a cross-sectional view showing a fuel tank according to a second embodiment.
The fuel tank 40 is provided with a tank contracting means 41 in the tank body 12, and the other configuration is the same as that of the fuel tank 10 of the first embodiment.

The tank reduction means 41 includes an open / close valve 44 in a communication passage 43 that connects the tank body 12 and the intake passage 42 of the fuel 17, and includes a remaining amount detection unit 23 that detects the remaining amount of the fuel 17 in the tank body 12, A control unit 45 that opens the on-off valve 44 based on a detection signal when the remaining amount detection unit 23 detects a decrease in the fuel 17 is provided.
The on-off valve 44 is an on / off valve set to a normally closed state.

  The intake passage 42 is maintained in a negative pressure state by driving the engine 46. In this state, the throttle valve 47 is opened to suck the fuel gas as indicated by the arrow B and guide it to the combustion chamber of the engine 46. Is.

  The control unit 45 confirms the decrease in the fuel 17 based on the detection signal sent from the remaining amount detection unit 23, and transmits an open signal to the on-off valve 44 when confirming the decrease in the fuel 17.

Next, the operation of the fuel tank 40 will be described with reference to FIG.
FIGS. 4A and 4B are diagrams illustrating an example in which the fuel tank according to the second embodiment is contracted.
In (a), when the fuel 17 in the tank body 12 decreases, the arm 28 swings downward about the base end 28a as in the first embodiment, and the fuel 17 decreases in the control unit 45. Detecting that

When the decrease in the fuel 17 is detected, an open signal is transmitted from the control unit 45 to the on-off valve 44, and the on-off valve 44 is opened. When the engine 46 is driven, the intake passage 42 is in a negative pressure state.
In this state, the throttle valve 47 is opened, and the air and fuel vapor in the tank body 12 are sucked into the communication passage 43 as shown by the arrow C.

  Air or fuel vapor sucked into the communication passage 43 is sucked into the intake passage 42 as indicated by an arrow D. Air or fuel vapor sucked into the intake passage 42 is guided to the combustion chamber of the engine 46 through the intake passage 42 and burned in the combustion chamber.

  Thereby, the air and fuel vapor in the tank body 12 are removed from the tank body 12, and the tank body 12 is brought into a negative pressure state.

In (b), the tank main body 12 is suitably reduced as described in the first embodiment by setting the space 16 in the tank main body 12 to a negative pressure state by the tank reducing means 41.
As in the first embodiment, the control unit 45 detects that the ceiling 13 has approached the fuel surface 17a based on the detection signal sent from the remaining amount detection unit 23, and closes the open / close valve 44. Tell. By closing the on-off valve 44, the contraction of the tank body 12 is stopped.

  As described above, according to the fuel tank 40 of the second embodiment, an effect similar to that of the first embodiment, that is, an effect that the generation amount of fuel vapor can be surely suppressed can be obtained.

  In addition, according to the fuel tank 40 of the second embodiment, the configuration of the tank reducing means 41 can be simplified by using the intake passage 42 provided in a normal vehicle as the tank reducing means 41. Can do.

Modified Example of Second Embodiment FIG. 5 is a cross-sectional view showing a fuel tank according to a modified example of the second embodiment.
The fuel tank 50 of the modified example includes the tank body 12 provided with a tank contracting means 51, and the other configuration is the same as that of the fuel tank 40 of the third embodiment.

  The tank reducing means 51 uses a float valve 52 in place of the remaining amount detecting part 23, the on-off valve 44 and the control part 45 (see FIG. 3) which are constituent members of the tank reducing means 51 of the second embodiment. It is.

  The float valve 52 has a casing 53 disposed in the tank body 12, and the casing 53 is attached to the ceiling portion 13 with the upper opening 53 a of the casing 53 facing the opening end 43 a of the communication passage 43. The float 55 is provided so that it can be raised and lowered, and a valve body 56 is provided on the top of the float 55. When the float 55 is raised, the opening end 43a of the communication passage 43 is closed by the valve body 56 (state shown in the figure), and the float 55 is lowered. In this case, the valve body 56 is configured to be separated from the opening end 43a of the communication passage 43 to open the communication passage 43.

The casing 53 is provided with an opening 53b at the bottom and an introduction port 53c.
The float 55 is a floating body that is kept floating on the fuel surface 17a by the buoyancy of the fuel 17 when the fuel 17 enters the casing 53 from the opening 53b or the introduction port 53c.
When the float 55 is lifted by buoyancy, the valve body 56 is applied to the opening end 43a of the communication passage 43, and the opening end 43a is closed as shown in the figure.

According to the modified fuel tank 50, when the fuel 17 in the tank body 12 decreases, the float 55 moves down together with the fuel surface 17a.
The valve body 56 moves away from the opening end 43 a of the communication passage 43 and opens the communication passage 43. When the engine 46 is driven, the intake passage 42 is in a negative pressure state.

In this state, the throttle valve 47 is opened, and the air and fuel vapor in the tank body 12 are sucked into the communication passage 43 through the inlet 53c of the casing 53.
Air or fuel vapor sucked into the communication passage 43 is guided to the combustion chamber of the engine 46 through the intake passage 42 and burned in the combustion chamber (not shown).

Thereby, the air and fuel vapor in the tank body 12 are removed from the tank body 12, and the tank body 12 is brought into a negative pressure state.
By making the space 16 in the tank main body 12 into a negative pressure state by the tank reducing means 51, the tank main body 12 is preferably reduced as described in the first embodiment.

When the tank body 12 shrinks and the ceiling 13 approaches the fuel surface 17a, the float 55 is held in a state of being floated on the fuel surface 17a by the buoyancy of the fuel 17.
The float 55 rises, the valve body 56 closes the open end 43a of the communication passage 43, and the contraction of the tank body 12 is stopped.

According to the fuel tank 50 of the modified example, the same effect as the fuel tank 40 of the second embodiment can be obtained.
Furthermore, according to the fuel tank 50 of the modified example, the float valve 52 is used in place of the remaining amount detection unit 23, the on-off valve 44, and the control unit 45 (see FIG. 3), thereby reducing the number of parts and simplifying the configuration. Can be achieved.

Third Embodiment FIG. 6 is a cross-sectional view showing a fuel tank according to a third embodiment.
The fuel tank 60 is provided with a tank contracting means 61 in the tank body 12, and the other configuration is the same as that of the fuel tank 10 of the first embodiment.

The tank reduction means 61 includes an open / close valve 64 in the outside air introduction passage 63 of the canister 62 that stores fuel vapor in the tank body 12, and a remaining amount detection unit 23 that detects the remaining amount of the fuel 17 in the tank body 12. When the remaining amount detection unit 23 detects a decrease in the fuel 17, a control unit 65 that closes the on-off valve 64 based on the detection signal is provided.
The on-off valve 64 is an on / off valve set to a normally open state.

The canister 62 communicates with the tank body 12 through the first passage 66, communicates with the intake passage 42 through the second passage 67, and includes activated carbon 68 inside.
A check valve 69 is provided in the middle of the first passage 66.

According to the canister 62, when the fuel vapor in the tank body 12 enters the canister 62 through the check valve 69 and the first passage 66, the fuel vapor that has entered enters the activated carbon 68.
When the engine 46 is driven in this state, the second passage 67 becomes negative pressure, and the outside air (air) enters the canister 62 through the outside air introduction passage 63 and the on-off valve 64 as indicated by an arrow.

  The fuel vapor is desorbed from the activated carbon 68 when the entering air passes through the activated carbon 68 as shown by the arrow. The desorbed fuel vapor is guided to the second passage 67 and the intake passage 42, and this fuel vapor is guided to the combustion chamber of the engine 46 through the intake passage 42 for combustion.

  The control unit 65 confirms the decrease of the fuel 17 based on the detection signal sent from the remaining amount detection unit 23, and transmits a close signal to the on-off valve 64 when confirming the decrease of the fuel 17.

Next, the operation of the fuel tank 60 will be described with reference to FIG.
FIGS. 7A and 7B are diagrams illustrating an example in which the fuel tank according to the third embodiment is contracted.
In (a), when the fuel 17 in the tank body 12 decreases, the arm 28 swings downward about the base end 28a as in the first embodiment, and the fuel 17 decreases by the control unit 65. Detecting that

When the decrease of the fuel 17 is detected, a closing signal is transmitted from the control unit 65 to the on-off valve 64, and the on-off valve 64 is closed.
When the engine 46 (see FIG. 6) is driven in this state, the intake passage 42 (see FIG. 6) and the first and second passages 51 and 52 are in a negative pressure state, and air and fuel vapor in the tank body 12 Is sucked into the first passage 66 through the check valve 69 as shown by an arrow E.

Air or fuel vapor sucked into the first passage 66 is guided to the second passage 67 as indicated by an arrow F through the canister 62.
The air and fuel vapor sucked into the second passage 67 are guided to the combustion chamber of the engine 46 (see FIG. 6) through the intake passage 42 and burned in the combustion chamber.

  Thereby, the air and fuel vapor in the tank body 12 are removed from the tank body 12, and the tank body 12 is brought into a negative pressure state.

In (b), the tank main body 12 is suitably reduced as described in the first embodiment by setting the space 16 in the tank main body 12 to a negative pressure state by the tank reduction means 51.
As in the first embodiment, the control unit 65 detects that the ceiling 13 has approached the fuel surface 17a based on the detection signal sent from the remaining amount detection unit 23, and opens the open / close valve 64. Tell. By opening the on-off valve 64, the contraction of the tank body 12 is stopped.

  As described above, according to the fuel tank 60 of the third embodiment, the same effect as that of the first embodiment, that is, the effect that the generation amount of fuel vapor can be surely suppressed can be obtained.

  In addition, according to the fuel tank 60 of the third embodiment, the configuration of the tank reducing means 61 can be simplified by using the canister 62 provided in a normal vehicle as the tank reducing means 61. it can.

Fourth Embodiment FIG. 8 is a cross-sectional view showing a fuel tank according to a fourth embodiment.
The fuel tank 70 is provided with a tank contracting means 71 in the tank body 12, and the other configuration is the same as that of the fuel tank 10 of the first embodiment.

The tank reduction means 71 includes weight members 72, 72 on the ceiling (upper part) 13 of the tank body 12, connects the exhaust passage 73 to the tank body 12, and opens and closes the exhaust passage 73 in the middle of the exhaust passage 73. And a remaining amount detector 23 for detecting the remaining amount of the fuel 17 in the tank body 12. When the remaining amount detector 23 detects a decrease in the fuel 17, the opening / closing valve 74 is set based on the detection signal. An opening control unit 75 is provided.
The on-off valve 74 is an on / off valve that is set in a normally closed state and opens and closes the tank body 12.

The weight member 72 is a weight having a rectangular cross section, and is a weight that uniformly contracts the entire bellows-shaped central portion 15 a provided on the peripheral wall 15.
A recess 72 a is formed in the weight member 72, and the detection unit main body 26 of the remaining amount detection unit 23 is received in the recess 72 a.

  The control unit 75 confirms the decrease in the fuel 17 based on the detection signal sent from the remaining amount detection unit 23, and transmits an open signal to the on-off valve 74 when confirming the decrease in the fuel 17.

Next, the operation of the fuel tank 70 will be described with reference to FIG.
FIGS. 9A and 9B are views for explaining an example of contracting the fuel tank according to the fourth embodiment.
In (a), when the fuel 17 in the tank body 12 decreases, the arm 28 swings downward about the base end 28a as in the first embodiment, and the fuel 17 decreases by the control unit 75. Detecting that

When the decrease of the fuel 17 is detected, an open signal is transmitted from the control unit 75 to the on-off valve 74, and the on-off valve 74 is opened.
Since the weight members 72 and 72 are placed on the ceiling portion 13 of the tank body 12, the load F <b> 1 of the weight members 72 and 72 is applied to the ceiling portion 13.

With this load F1, the peripheral wall 15 (specifically, the bellows-shaped central portion 15a) of the tank body 12 starts to contract, and the ceiling portion 13 descends as shown by an arrow G.
At the same time, air and fuel vapor in the tank body 12 are removed from the exhaust passage 73 and the on-off valve 74 as indicated by an arrow H.

In (b), as the ceiling part 13 descends as indicated by an arrow G (see (a)), the tank body 12 is suitably reduced as described in the first embodiment.
As in the first embodiment, the control unit 75 detects that the ceiling 13 has approached the fuel surface 17a based on the detection signal sent from the remaining amount detection unit 23, and closes the open / close valve 73. Tell. By closing the on-off valve 74, the contraction of the tank body 12 is stopped.

  As described above, according to the fuel tank 70 of the fourth embodiment, the same effect as that of the first embodiment, that is, the effect that the generation amount of fuel vapor can be reliably suppressed can be obtained.

  In addition, according to the fuel tank 70 of the fourth embodiment, the tank reduction means 71 has a simple configuration in which the weight member 72 is provided on the ceiling portion 13 of the tank body 12, thereby reducing the cost of the tank reduction means 71. Can be suppressed.

Fifth Embodiment FIG. 10 is a cross-sectional view showing a fuel tank according to a fifth embodiment.
The fuel tank 80 is provided with a spring member 83 in the tank reducing means 81, and the other configuration is the same as that of the fuel tank 70 of the fourth embodiment.

  The tank contracting means 81 includes a spring member 83 that presses the tank body 12 in a contracting direction, and includes an open / close valve 74 that opens and closes the tank body 12, and a remaining amount detection unit that detects the remaining amount of fuel in the tank body 12. 23, and a controller 75 that opens the on-off valve 74 based on the detection signal when the remaining amount detector 23 detects a decrease in the fuel 17.

The spring member 83 is sandwiched between the ceiling part (upper part) 13 of the tank body 12 and the ceiling part 11a of the exterior tank 11, and applies a pressing force F2 (see FIG. 11) to the ceiling part 13 of the tank body 12. It is a member.
By applying a pressing force F <b> 2 to the ceiling portion 13 with the spring member 83, the entire bellows-shaped central portion 15 a provided on the peripheral wall 15 of the tank body 12 can be uniformly contracted.

According to the fuel tank 80 of the fifth embodiment, it is possible to obtain the same effect as that of the first embodiment, that is, the effect that the generation amount of the fuel vapor can be surely suppressed.
In addition, according to the fuel tank 80 of the fifth embodiment, the relatively light spring member 83 is used as the tank contracting means 81, so that the vehicle weight is compared with the fuel tank 70 of the fourth embodiment. Can be reduced.

  In the above-described embodiment, the tank body 12 has been described as an example in which the capacity is changed by expanding and contracting the bellows-shaped peripheral wall 15. However, as another example of the tank body, for example, a material that can be expanded and contracted It can also be formed.

  Moreover, although the said embodiment demonstrated the example using the thing of the float arm type which connected the float 29 to the arm 28 as the residual amount detection part 23, it does not limit to this.

  Furthermore, in the above-described embodiment, the example in which the exterior tank 11 is provided outside the tank body 12 has been described. However, the tank body 12 alone may be used.

  In the fourth to fifth embodiments, the example in which the remaining amount detecting unit 23, the on-off valve 74, the control unit 75, and the like are used as the tank reducing means 71 and 81 has been described. However, the second embodiment is modified. As an example, the float valve 52 (see FIG. 5) can be used in place of the remaining amount detection unit 23, the on-off valve 74, and the control unit 75.

In addition, in the third embodiment, a float arm in which the base end portion 28a of the arm 28 is rotatably provided in the detection portion main body 26 as the remaining amount detection portion 23, and the float 29 is provided in the distal end portion 28a of the arm 28. Although the example using the formula has been described, it is also possible to use a float valve 52 (see FIG. 5) provided with the detector main body 26 instead.
By using the float valve 52, the check valve 69 can be removed from the first passage 66 shown in FIG.

  The present invention is suitable for application to a fuel tank configured to change the capacity of the tank body in accordance with the remaining amount of fuel stored in the tank body.

It is sectional drawing which shows 1st Embodiment of the fuel tank which concerns on this invention. It is a figure explaining the example which shrinks the fuel tank concerning a 1st embodiment. It is sectional drawing which shows the fuel tank which concerns on 2nd Embodiment. It is a figure explaining the example which shrinks the fuel tank concerning a 2nd embodiment. It is sectional drawing which shows the fuel tank which concerns on the modification of 2nd Embodiment. It is sectional drawing which shows the fuel tank which concerns on 3rd Embodiment. It is a figure explaining the example which shrinks the fuel tank concerning a 3rd embodiment. It is sectional drawing which shows the fuel tank which concerns on 4th Embodiment. It is a figure explaining the example which shrinks the fuel tank concerning a 4th embodiment. It is sectional drawing which shows the fuel tank which concerns on 5th Embodiment.

Explanation of symbols

  10, 40, 50, 60, 70, 80 ... Fuel tank, 12 ... Tank body, 13 ... Ceiling (upper part), 17 ... Fuel, 20, 41, 51, 61, 71, 81 ... Tank reduction means, 22 ... Vacuum pump, 23 ... remaining amount detection unit, 24, 45, 65, 75 ... control unit, 62 ... canister, 44 ... outside air introduction passage, 44, 64, 74 ... open / close valve, 42 ... intake passage, 46 ... engine, 43 ... Communication passage, 72 ... Weight member, 82 ... Spring member.

Claims (6)

In the fuel tank that has a tank body that stores the fuel to be supplied to the engine, and in order to change the capacity of the tank body according to the remaining amount of fuel stored in the tank body,
A fuel tank comprising tank reducing means for reducing the tank body according to the amount of fuel decrease when the fuel in the tank body decreases. The tank reducing means is
A vacuum pump communicating with the tank body;
It has a remaining amount detection unit that detects the remaining amount of fuel in the tank body,
When detecting a decrease in fuel in the remaining amount detection unit, a control unit for driving the vacuum pump based on the detection signal is provided,
2. The fuel tank according to claim 1, wherein the tank body is reduced by driving the vacuum pump to bring the inside of the tank body into a negative pressure state. The tank reducing means is
A communication passage connecting the tank body and the intake passage of the engine;
The communication passage is provided with an on-off valve that opens when the fuel is reduced,
2. The fuel tank according to claim 1, wherein when the on-off valve is opened, a negative pressure in the intake passage is utilized to reduce the tank main body to a negative pressure inside the tank main body. The tank reducing means is
The fuel vapor generated in the tank body is stored in the inside, and the stored fuel vapor is utilized with the outside air taken in from the outside air introduction passage, and the canister is guided to the engine through the intake passage of the engine.
An open / close valve is provided in the outside air introduction passage,
It has a remaining amount detection unit that detects the remaining amount of fuel in the tank body,
When the remaining amount detection unit detects a decrease in fuel, the control unit closes the on-off valve based on the detection signal,
2. The fuel tank according to claim 1, wherein when the on-off valve is closed, a negative pressure in the intake passage is utilized to reduce the tank main body to a negative pressure inside the tank main body. The tank reducing means is
A weight member is provided on the upper part of the tank body,
It has an open / close valve that opens and closes the tank body,
2. The fuel tank according to claim 1, wherein when the fuel in the tank body decreases, the tank body is reduced by the weight member by opening the on-off valve. The tank reducing means is
Comprising a spring member that presses the tank body in the direction of shrinking,
It has an open / close valve that opens and closes the tank body,
2. The fuel tank according to claim 1, wherein when the fuel in the tank body decreases, the tank body is reduced by the spring member by opening the on-off valve.

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