JP5736918B2 - Fuel tank structure - Google Patents

Description

  The present invention relates to a fuel tank structure including a fuel tank that contains fuel.

  As a fuel tank mounted on an automobile, Patent Document 1 describes a structure having an upper wall portion that can change a tank capacity by elastic deformation in accordance with the amount of evaporated fuel in the tank.

  As described above, in a fuel tank having a variable capacity, it is desirable to be able to detect this change when a change occurs in the displacement state of the displacement portion.

JP 2009-30539 A

  In view of the above facts, an object of the present invention is to obtain a fuel tank structure capable of detecting a change in the displacement state of a displacement portion in a fuel tank capable of changing a volume by displacement of the displacement portion. .

According to the first aspect of the present invention, a fuel tank that stores fuel, and a displacement portion that is provided on a part of the outer surface of the fuel tank and that is displaced according to the tank internal pressure of the fuel tank so as to vary the volume of the fuel tank. And a plurality of locations in the displacement portion, and when there is no change in the displacement state of the displacement portion, the displacement amounts at a plurality of locations where the displacement amounts are substantially equal are detected, and the difference between the displacement amounts at the plurality of locations is Displacement amount detecting means for detecting a change in the displacement state of the displacement portion by comparing with a predetermined displacement difference threshold value set in advance .

  In this fuel tank structure, the displacement part provided in a part of the outer surface of the fuel tank is displaced according to the tank internal pressure of the fuel tank, whereby the volume of the fuel tank can be changed.

  In addition, this fuel tank structure has a displacement amount detecting means for detecting the displacement amount of the displacement portion. For this reason, when there is an abnormality in the displacement state of the displacement portion, the displacement amount detected by the displacement amount detection means is different from the original displacement amount (the displacement amount when there is no abnormality). . Thereby, it is possible to detect an abnormality in the displacement state of the displacement portion.

Furthermore, since displacement amounts at a plurality of locations of the displacement portion are detected, it is possible to more accurately detect a change in the displacement state of the displacement portion.

And when the difference of the displacement amount of the several location of a displacement part exceeds the predetermined displacement threshold value preset, it can detect that the displacement part inclines with respect to an original displacement.

According to a second aspect of the present invention, in the first aspect of the invention, the displacement amount detecting means can compare the displacement amount of the displacement portion with a predetermined displacement amount threshold value set in advance.

  Therefore, when the displacement amount of the displacement portion exceeds a predetermined displacement amount threshold value set in advance, it can be detected that the displacement portion has not caused the original displacement.

In the invention described in claim 3, in the invention of claim 1 or claim 2, wherein the displacement amount detecting means, provided on at least one of the vehicle body panel opposite to the displacement portion and the displacement portion A service hole is provided that includes a displacement amount detection sensor, is provided with a partial opening in the vehicle body panel, and allows access to the displacement portion from the opposite side of the fuel tank.

  Thus, the displacement amount of the displacement portion can be accurately measured by using the displacement amount detection sensor provided on at least one of the displacement portion and the vehicle body panel.

  Moreover, by accessing the displacement part through the service hole, the displacement part can be inspected. Depending on the shape and position of the service hall, the displacement detection sensor can be inspected.

According to a fourth aspect of the present invention, there is provided the sealing member according to the third aspect , wherein the sealing member is provided so as to surround the displacement portion between the vehicle body panel and the fuel tank and seals the enclosed interior from the outside. Have.

  Since the seal member surrounds the displacement portion, foreign matters (dust, moisture, etc.) are prevented from entering the enclosed interior from the outside. Thereby, a displacement part can be displaced stably. Moreover, it can suppress that a foreign material influences the detection of the displacement amount by a displacement amount detection sensor.

According to a fifth aspect of the present invention, in the third or fourth aspect of the present invention, provided at least one of the displacement portion and the vehicle body panel, and the opposed portion of the displacement amount detection sensor and the displacement amount detection sensor. And a spacer member that shortens the distance between the displacement portion and the vehicle body panel than the distance between the spacer member and the vehicle body panel.

  For example, in the case where the displacement amount detection sensor itself has a structure facing the sensor body, the facing part corresponds to the facing part. Further, even when the displacement amount detection sensor has a structure that does not have such an opposing portion, the portion (for example, the vehicle body) that faces the portion (for example, the displacement portion) to which the displacement amount detection sensor is attached. Part of the panel), the facing part corresponds to the “facing part” according to the present invention.

  In any case, when the displacement part approaches the vehicle body panel, the displacement part is interposed via the spacer member before the displacement amount detection sensor and the opposite part of the displacement amount detection sensor come into contact with each other. Contact with the body panel. As a result, the displacement amount detection sensor and the facing portion of the displacement amount detection sensor do not come into contact with each other, and interference between the displacement amount detection sensor and the facing portion can be prevented.

According to a sixth aspect of the invention, in the first aspect of the invention according to any one of the first to fifth aspects, the apparatus further comprises pump means for pressurizing or depressurizing the inside of the fuel tank.

  By detecting the displacement amount of the displacement portion with the displacement amount detection means in a state where the inside of the fuel tank is pressurized or depressurized using the pump means, it becomes possible to more accurately detect the change in the displacement state of the displacement portion. . In particular, the displacement amount of the displacement portion is detected by the displacement amount detection means while a constant pressure (either positive pressure or negative pressure) is applied to the fuel tank by the pump means, so that the displacement state of the displacement portion is detected. Anomalies can be detected more accurately and easily. For example, when the displacement amount detected by the displacement amount detection means is different from the displacement amount of the displacement portion assumed from the capacity of the pump means and the driving time, it can be determined that the displacement state is abnormal.

According to a seventh aspect of the invention, in the sixth aspect of the invention, the tank inner pressure sensor for detecting the tank inner pressure is provided, and the pump means is configured to stabilize the tank inner pressure detected by the tank inner pressure sensor. The inside of the fuel tank is pressurized or depressurized while the fuel tank is on.

  The pump means pressurizes or depressurizes the inside of the fuel tank while the tank internal pressure detected by the tank internal pressure sensor is stable. That is, the amount of displacement can be detected in a state where there is little inadvertent displacement of the displacement portion due to fluctuations in the tank internal pressure, and the detection accuracy with respect to the change in the displacement state is increased and the detection becomes easy.

  Since the present invention has the above-described configuration, it is possible to detect a change in the displacement state of the displacement portion in the fuel tank capable of changing the volume by the displacement of the displacement portion.

It is a schematic block diagram which shows the fuel tank structure of 1st Embodiment of this invention. It is sectional drawing which expands partially and shows the fuel tank structure of 1st Embodiment of this invention in the state which the displacement part has not displaced. It is sectional drawing which expands partially and shows the fuel tank structure of 1st Embodiment of this invention in the state which the displacement part displaced upwards. It is a block diagram of the fuel tank structure of a 1st embodiment of the present invention. It is a flowchart in the case of detecting the displacement state of a displacement part in the fuel tank structure of 1st Embodiment of this invention. It is sectional drawing which expands partially and shows the fuel tank structure of 1st Embodiment of this invention in the state which the displacement part displaced diagonally.

  FIG. 1 shows a fuel tank structure 12 according to a first embodiment of the present invention. The fuel tank structure 12 has a fuel tank 14 disposed below the floor panel 16 of the vehicle body. As an example, the fuel tank 14 is formed in a substantially rectangular parallelepiped box shape, and can store fuel therein. A fuel pump 18 is accommodated in the fuel tank 14, and the fuel can be sent to the engine by driving the fuel pump 18.

  On the upper wall 14T of the fuel tank 14, as shown in detail in FIG. 2, a bellows-like (shaped waved up and down) thin portion 20 is formed. The thin portion 20 is thinner than other portions of the fuel tank 14 and is formed in an annular shape (or a closed curve) when the fuel tank 14 is viewed from above. The inner portion of the thin portion 20 is a displacement portion 22.

  The fuel tank 14 is a vehicle body component such as a floor panel 16 using a fixture (not shown) in a portion other than the thin wall portion 20 and the displacement portion 22 (in this embodiment, for example, the bottom wall 14B and the side wall 14S of the fuel tank 14). Is attached.

  As shown in FIG. 3, when the tank internal pressure of the fuel tank 14 changes, the displacement portion 22 is displaced up and down while the thin portion 20 is deformed, thereby changing the volume of the fuel tank 14. FIG. 3 shows an example in which the tank internal pressure of the fuel tank 14 increases, the displacement portion 22 moves upward, and the volume of the fuel tank 14 is increased. When the tank internal pressure of the fuel tank 14 is lowered, the displacement portion 22 is displaced downward and the volume of the fuel tank 14 is reduced.

  As shown in FIG. 1, the gas layer inside the fuel tank 14 is connected to a canister 26 by a vapor pipe 24. In the gas layer, there is a gas containing evaporated fuel. When this gas is sent to the canister, the evaporated fuel component is adsorbed by the adsorbent (activated carbon or the like) in the canister 26. Then, atmospheric components are discharged into the atmosphere through the atmospheric open pipe 28.

  A key-off pump 30 is provided in the atmosphere release pipe 28. By driving the key-off pump 30, the inside of the fuel tank 14 can be pressurized, and abnormality detection (particularly, detection of holes) of the fuel tank 14 and its surroundings can be performed. As shown in FIG. 4, the key-off pump 30 is driven and controlled by a control device 32. Note that the inside of the fuel tank 14 may be decompressed by the key-off pump 30.

  As shown in detail in FIGS. 2 and 3, one or more (two in the present embodiment) displacement amount detection sensors 34 are attached to the displacement portion 22. In the present embodiment, as the displacement amount detection sensor 34, a first detector 34A attached to the upper surface of the displacement portion 22 and a second detector attached to the lower surface of the floor panel 16 at a position facing the first detector 34A. 34B. The displacement detection sensor 34 is a so-called capacitance sensor, and can detect these distances from the capacitance between the first detector 34A and the second detector 34B. Yes. Thus, by detecting the distance between the first detector 34A and the second detector 34B, it is possible to detect the amount of displacement of the displacement portion 22 at the portion where the displacement amount sensor 34 is attached.

  In this embodiment, as can be seen from FIG. 2 in particular, a position that is symmetrical with respect to the center 22C of the displacement part 22, in other words, a position where the displacement amount is substantially equal when there is no change in the displacement state of the displacement part 22. In addition, two displacement amount detection sensors 34 are arranged.

  The displacement amount data detected by the displacement amount detection sensor 34 is sent to the control device 32 as shown in FIG. In the control device 32, the displacement data sent can be recorded over a predetermined time. The control device 32 can also calculate the difference between the displacement amounts obtained by the two displacement amount detection sensors 34.

  The displacement portion 22 is provided with a protrusion 36 that partially protrudes the plate material constituting the displacement portion 22 at a position surrounding the first detector 34A in each of the displacement amount detection sensors 34. The protruding portion 36 has a protruding height determined such that a distance D1 between the tip thereof and the lower surface of the floor panel 16 is shorter than a distance D2 between the first detector 34A and the second detector 34B. In other words, the protruding height of the protruding portion 36 is higher than the combined height (thickness) of the first detector 34A and the second detector 34B. The protrusion 36 constitutes a “spacer member” of the present invention.

  Note that the spacer member of the present invention is not limited to the protruding portion 36 described above. For example, a portion protruding downward from the floor panel 16 may be provided, and the interval between the tip (lower end) of the protruding portion and the displacement portion 22 may be shorter than the interval D2. Further, the protruding portion protruding downward from the floor panel 16 and the protruding portion 36 protruding upward from the displacement portion 22 may be used in combination. The protruding portion 36 (the portion constituting the spacer member) is not limited to a configuration that partially deforms the displacement portion 22 or the floor panel. For example, a member different from the displacement portion 22 or the floor panel 16 is used. Also good.

  Around the thin portion 20, a sealing material 38 that contacts both the upper wall 14 </ b> T of the fuel tank 14 and the floor panel 16 is disposed. The sealing material 38 surrounds the circumference of the thin portion 20 over the entire circumference, and seals the enclosed interior 40 from the exterior 42. The interior 40 is surrounded not only by the sealing material 38 but also by the upper wall 14T and the floor panel 16. For this reason, foreign matters such as dust and moisture are prevented from entering from the outside 42 to the inside 40, and the influence of the foreign matter when the displacement portion 22 is displaced is reduced. Further, the foreign matter does not affect the detection of the displacement amount by the displacement amount detection sensor 34.

  The sealing material 38 has a structure (for example, a porous shape) so as to allow movement of gas (air) between the inside 40 and the outside 42. For this reason, the displacement of the displacement part 22 is not subjected to resistance by the atmospheric pressure in the interior 40.

  A service hole 44 is formed in the floor panel 16 so as to surround an outer portion further than the second detector 34B of the two displacement amount detection sensors 34. In the normal state, the service hole 44 is closed by the lid member 46, but when the lid member 46 is removed, the displacement portion 22 and the first detector 34 </ b> A are accessed from the upper side of the floor panel 16 through the service hole 44. Inspection and the like can be easily performed.

  Since the second detector 34B is attached to the lid member 46, when the lid member 46 is removed from the floor panel 16, the second detector 34B can be easily inspected.

  The service hole 44 may be formed on the floor panel 16 inside the two second detectors 34B. In this structure, the second detector 34 </ b> B is not attached to the lid member 46, and the second detector 34 </ b> B is attached to the floor panel 16 around the service hole 44.

  As shown in FIG. 1, the fuel tank 14 includes a tank internal pressure sensor 50 that detects the tank internal pressure. The tank internal pressure data detected by the tank internal pressure sensor 50 is sent to the control device 32 as shown in FIG.

  Further, as shown in FIG. 4, the fuel tank structure 12 has a display device 48 controlled by the control device 32. If there is an abnormality in the displacement state of the displacement portion 22, the display device 48 displays this and notifies the vehicle occupant, the operator performing maintenance, or the like. The display device 48 may be, for example, a visually appealing means such as a display display or a display lamp provided on an instrument panel of a vehicle, or may be an appealing means such as a warning sound or sound. Further, these may be used in combination.

  The displacement amount detection means of the present invention includes the displacement amount detection sensor 34, the control device 32, and the display device 48.

  Next, an operation of the fuel tank structure 12 of the present embodiment and a method for detecting a change in the displacement state of the displacement portion 22 will be described.

  In the fuel tank structure 12 of the present embodiment, the temperature of the fuel and gas in the fuel tank 14 (in the tank) due to the influence of the surrounding air temperature rising with the fuel tank 14 sealed, for example, while the vehicle is parked. Consider the case where the temperature rises. As the tank internal temperature rises, the internal pressure of the fuel tank 14 also rises.

  In the fuel tank 14 of the present embodiment, the thin wall portion 20 is formed on the upper wall 14T, and the inner portion thereof is the displacement portion 22. Therefore, when the internal pressure of the fuel tank 14 rises and reaches a predetermined value, the displacement portion 22 rises and the volume of the fuel tank 14 increases as shown by a two-dot chain line in FIG.

  On the other hand, when the temperature in the fuel tank 14 decreases due to a decrease in ambient temperature or the like, and the tank internal pressure also decreases, the displacement portion 22 descends and the volume of the fuel tank 14 decreases. Thus, since the displacement part 22 displaces, the volume of the fuel tank 14 is increased / decreased, so that the change in the tank internal pressure of the fuel tank 14 is suppressed.

  In the fuel tank structure 12 of the present embodiment, it is possible to detect a change in the displacement state of the displacement portion 22 by a displacement state change detection method (hereinafter referred to as “change detection method”) in accordance with the control flow shown in FIG. It is. Note that this abnormality detection process (anomaly detection method) may be performed automatically after a predetermined time has elapsed since the vehicle stopped, or may be performed manually. When it is performed automatically, for example, it can be performed at the same timing as “perforation detection” for the fuel tank 14.

  First, in step S102, it is determined whether or not the tank internal pressure detected by the tank internal pressure sensor 50 is stable. For example, the tank internal pressure is often stable while the vehicle is stopped (a state in which a certain amount of time has elapsed since the ignition was turned off). If the tank internal pressure is not stable, this determination is continued in step S102 until the tank internal pressure becomes stable.

  If the tank internal pressure is stable, the key-off pump 30 is driven to pressurize the fuel tank 14 in step S104. Thereby, the displacement part 22 displaces upwards. The fuel tank 14 may be depressurized by driving the key-off pump 30. In this case, the displacement part 22 is displaced downward, but the following control is essentially the same as when the displacement part 22 is displaced upward. Is the same.

  In step S106, it is determined whether or not the displacement amount of the displacement portion 22 detected by the displacement amount detection sensor 34 is within a predetermined range (first threshold, “displacement amount threshold” in the present invention). That is, since the tank internal pressure of the fuel tank 14 is detected by the tank internal pressure sensor 50, the displacement amount of the displacement portion 22 can be estimated from the tank internal pressure. However, when there is an abnormality in the displacement state of the displacement portion 22, the displacement portion 22 is displaced by a displacement amount different from the estimated displacement amount. If it is determined in step S106 that the detected displacement amount is not within the predetermined range with respect to the estimated displacement amount, the process proceeds to step S108. In step S108, the display device 48 notifies that the displacement state of the displacement portion 22 has changed. This notification may be performed immediately or may be performed when the engine is started next time.

  In step S106, a threshold value (third threshold value) smaller than the first threshold value is set, and the displacement amount of the displacement part 22 detected by the displacement amount detection sensor 34 does not reach the third threshold value. In this case, a process of moving to step S108 may be added.

  If it is determined in step S106 that the detected displacement is within a predetermined range with respect to the estimated displacement, the process proceeds to step S110. In step S110, the difference between the displacement amounts detected by the two displacement amount detection sensors 34 is calculated, and whether or not this difference is within a predetermined range (second threshold, “displacement difference threshold” in the present invention). Determine whether. That is, as shown by the two-dot chain line in FIG. 6, even if the displacement amount detected by the displacement amount detection sensor 34 is within the predetermined range with respect to the estimated displacement amount, In some cases, 22 is inclined and displaced. Therefore, in step S110, it is determined whether or not the degree of inclination of the displacement portion 22 is within a predetermined range.

  If it is determined in step S110 that the difference value of the displacement amount exceeds the predetermined range, the process proceeds to step S108, and the display device 48 is used to notify the change in the displacement state. If the value of the displacement difference does not exceed the predetermined range, this flow ends without performing notification by the display device 48.

  As described above, in the fuel tank structure 12 of the present embodiment, it is possible to detect a change in the displacement state of the displacement portion 22 using the displacement amount detected by the displacement amount detection sensor 34.

  Note that the timing for performing the abnormality detection method is not limited to when the vehicle is stopped. However, when the vehicle is stopped, the fluctuation of the tank internal pressure due to the fluctuation of the fuel in the fuel tank 14, the fuel consumption, the change in the fuel temperature, etc. is less than that during the traveling of the vehicle. Thus, since the change in the displacement state of the displacement portion 22 is detected in a state where the tank internal pressure is stable, the detection accuracy is increased.

  In executing the abnormality detection method, the tank internal pressure sensor 50 detects the tank internal pressure in the above example. Therefore, from the essence of the invention, the key-off pump 30 is not necessarily driven to pressurize or depressurize the fuel tank 14. do not have to. However, when the anomaly detection method is executed, the key-off pump 30 (pump means) is driven to apply a constant pressure each time to pressurize or depressurize the fuel tank 14 to detect the anomaly. Since the state can be kept constant, it is possible to detect anomalies more easily and accurately.

  In the flow shown in FIG. 5, it is determined whether or not the displacement amount of the displacement portion 22 detected by the displacement amount detection sensor 34 is within a predetermined range (step S <b> 106), and the displacement detected by the displacement amount detection sensor 34. Both determinations are made as to whether or not the amount difference value is within a predetermined range (step S110). Therefore, it is possible to more accurately detect a change in the displacement state of the displacement portion 22. Of course, in a configuration using two displacement amount detection sensors 34, only one of these determinations may be made. In particular, in the configuration having two or more displacement amount detection sensors, it is possible to determine whether or not the absolute value of the difference between the displacement amounts is within a predetermined range.

  When a plurality of displacement amount detection sensors are arranged, it is preferable that the displacement portion 22 is not excessively unevenly distributed. For example, when the displacement part 22 is circular when viewed from above, the displacement part 22 may be arranged at a constant distance from the center and at equal intervals in the circumferential direction.

  In contrast, the fuel tank structure of the present invention may have a configuration having only one displacement amount detection sensor. Even with this configuration, it is possible to determine whether or not the displacement detected by one displacement detection sensor is within a predetermined range.

  As a specific configuration of the displacement detection sensor, in the above description, a structure in which the first detector 34A is attached to the upper surface of the displacement portion 22 is described. However, the first detector 34A and the second detector 34B In the structure (capacitance sensor) that detects the amount of displacement based on the capacitance between the first detector 34A and the second detector 34A, for example, the first detector 34A is disposed on the lower surface of the displacement portion 22 (inside the fuel tank 14). It is also possible to arrange the two detectors 34B on the upper surface of the floor panel 16.

  The displacement detection sensor is not limited to the configuration based on the electrostatic capacity. For example, laser light or ultrasonic waves are emitted from one of the displacement portion 22 and the floor panel 16 toward the other, and from the time required for the reflection, A sensor of a type that detects a change in the distance between the displacement portion 22 and the floor panel 16 may be used. As described above, in the sensor configured to use laser light or ultrasonic waves, since one displacement amount detection sensor is sufficient for each displacement amount detection sensor, the structure can be simplified. .

  In the fuel tank structure of the present invention, in addition to the configuration of the above embodiment, the temperature in the tank that detects the temperature inside the fuel tank (which may be the fuel temperature or the temperature of the gas in the fuel tank). A sensor may be provided, and the determination in step S106 or step S110 may be corrected in consideration of the tank internal temperature detected by the tank internal temperature sensor. That is, since the rigidity of the material slightly changes depending on the temperature of the fuel tank 14, if the first threshold value or the second threshold value is corrected based on the rigidity change, the displacement portion can be more accurately detected. It is possible to detect an abnormality in the 22 displacement states.

  Even if the tank internal pressure sensor 50 is not provided, it is possible to detect a change in the displacement state of the displacement portion 22. That is, the tank internal pressure of the fuel tank 14 can be estimated from the drive capability and drive time of the key-off pump 30. Therefore, it is possible to determine whether or not the displacement amount of the displacement portion 22 detected by the displacement amount detection sensor is within a predetermined range. In addition, it is possible to determine whether or not the difference values of the displacement amounts detected by the plurality of displacement amount detection sensors are within a predetermined range regardless of the tank internal pressure.

  Further, in the configuration without the tank internal pressure sensor 50, it is impossible to determine whether or not the tank internal pressure is stable (determination in step S102 in FIG. 5). However, when a predetermined time has elapsed since the vehicle stopped, Should be considered stable.

  The structure of the fuel tank 14, in particular, the specific configuration of the displacement portion 22 is not limited to the above structure. For example, a displacement portion may be provided on the side wall 14S or the bottom wall 14B of the fuel tank. In this case, a part of the member constituting the vehicle body may be opposed to the side wall 14S and the bottom wall 14B as a facing portion, and the amount of displacement of the displacement portion 22 may be detected using the distance between the facing portion and the displacement portion. . The number of the displacement portions 22 is not limited to one in one fuel tank 14, and a plurality of the displacement portions 22 may be provided. In this case, it is preferable that an abnormality in the displacement state can be detected in each of the plurality of displacement portions 22.

  As the pump means of the present invention, the key-off pump 30 is used in the above, but other pumps may be used. However, when the key-off pump 30 provided in advance in the fuel tank structure 12 is used, it is not necessary to add a new pump means, and the present invention is configured at a low cost to detect a change in the displacement state of the displacement portion 22. It becomes possible.

  As the displacement amount detection means of the present invention, for example, the displacement amount detected by the displacement amount detection sensor 34 may be directly displayed on the display device 48. In this case, the control device 32 determines whether or not the displacement amount detected by each displacement amount detection sensor 34 exceeds the first threshold value, and the difference between the displacement amounts exceeds the second threshold value. It may be determined by an occupant, a maintenance worker, or the like instead of the control device 32.

  Further, the display device 48 need not be configured as a part of the vehicle. For example, the display device 48 may be configured to display on a general-purpose display or the like installed in a vehicle maintenance shop.

DESCRIPTION OF SYMBOLS 12 Fuel tank structure 14 Fuel tank 16 Floor panel 20 Thin part 22 Displacement part 22C Center of displacement part 30 Key-off pump 32 Control apparatus 34 Displacement amount detection sensor 36 Protrusion part 38 Sealing material 40 Inner 42 External 44 Service hole 48 Display apparatus 50 Tank Internal pressure sensor

Claims (7)

A fuel tank containing fuel;
A displacement portion that is provided on a part of the outer surface of the fuel tank and that varies according to the tank internal pressure of the fuel tank so that the volume of the fuel tank is variable;
If there is no change in the displacement state of the displacement portion at the plurality of displacement portions, the displacement amounts at a plurality of locations where the displacement amounts are substantially equal are detected, and the difference between the displacement amounts at the plurality of locations is set in advance. A displacement amount detection means for detecting a change in the displacement state of the displacement portion by comparing with a predetermined displacement difference threshold value ,
Having fuel tank structure. 2. The fuel tank structure according to claim 1 , wherein the displacement amount detection means can compare a displacement amount of the displacement portion with a predetermined displacement amount threshold value set in advance. 3. It said displacement detection means includes displacement amount detection sensor provided in at least one of the vehicle body panel opposite to the displacement portion and the displacement portion,
A service hole provided by partially opening the vehicle body panel, allowing access to the displacement part from the opposite side of the fuel tank;
The fuel tank structure according to claim 1 or 2 , comprising: A seal member provided to surround the displacement portion between the vehicle body panel and the fuel tank, and seals the enclosed interior from the outside;
The fuel tank structure according to claim 3 . The displacement portion and provided on at least one of the vehicle body panel, wherein with spacer members, to shorten the distance between the displacement portion and the vehicle body panel than the distance between the displacement detecting sensor and the displacement amount detection portion facing the sensor The fuel tank structure according to claim 3 or claim 4 . Pump means for pressurizing or depressurizing the inside of the fuel tank;
The fuel tank structure according to any one of claims 1 to 5 , comprising: A tank internal pressure sensor for detecting the tank internal pressure;
The fuel tank structure according to claim 6 , wherein the pump means pressurizes or depressurizes the inside of the fuel tank in a state where the tank internal pressure detected by the tank internal pressure sensor is stable.

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