JP5741399B2 - Fuel tank structure - Google Patents

Description

  The present invention relates to a fuel tank structure, and more particularly to a fuel tank structure of a tank applied to a fuel tank mounted on a vehicle such as an automobile.

  2. Description of the Related Art Conventionally, there are various types of fuel amount measuring devices provided in a fuel tank of an automobile or the like. As one of them, a fuel electrode is measured by using a vertically long detection electrode (sensor) extending in the vertical direction of the vehicle body. A configuration is adopted in which the position where the detection electrode contacts is detected to detect the liquid level.

  For example, a reference electrode in which the detection unit is always immersed in the liquid, a gas-phase electrode that is always outside the liquid, and a liquid surface electrode that intersects the liquid surface are combined, and the capacitance due to contact / non-contact between the electrode and the liquid The structure which detects a liquid level from the change of is proposed (for example, refer patent document 1).

  At this time, a configuration has been proposed in which the reference electrode that is always immersed in the liquid is laid along the bottom of the tank, and the liquid surface electrode that intersects the liquid surface extends in the vertical direction (see, for example, Patent Document 2). ).

  Further, a configuration has been proposed in which a remaining amount detection sensor provided in the fuel tank has a function of detecting foreign matter in the fuel tank (see, for example, Patent Document 3).

  Similarly, a configuration has been proposed in which the concentration of the liquid to be measured, the degree of deterioration, the mixing of foreign matter, and the like are detected from the change in capacitance detected by the sensor (see, for example, Patent Document 4).

JP 2010-025782 A JP 2008-524618 A JP 59-031418 A JP 2007-12962 A

  However, in order to detect the entry of foreign matter with a sensor that detects the amount of liquid from the change in capacitance as in the configurations described in Patent Documents 3 and 4, the foreign matter contained in the fuel contacts the sensor on the surface of the sensor. Although it is necessary to maintain the state, it is difficult to maintain the contact state between the foreign matter and the sensor surface due to fuel oscillation or pump suction.

  Further, if an L-shaped liquid level sensor such as the configuration described in Patent Document 2 is used, it can be detected when foreign matter settles on the surface of the sensor, but this also maintains the contact state for the above reason. The difficult problem is not solved.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel tank structure capable of stably detecting foreign matter using a liquid level sensor.

The fuel tank structure according to claim 1 is provided in a vehicle, and stores a fuel tank that stores fuel to be sent inside by a fuel tube connected to a delivery means, and a filter that covers a suction port that opens at the tip of the fuel tube. A liquid level sensor having a liquid level measuring unit for measuring the liquid level of the fuel in the fuel tank by electrostatic capacity, and provided on the liquid level sensor along the bottom surface of the fuel tank, and an electrode on the upper surface of the vehicle body the provided, along the surface of the filter to detect the electrostatic capacity of the fuel in the opposing electrode disposed so as to keep it at a predetermined distance, at least in part by the filter placed at a predetermined distance And a fuel reference measuring unit covered from the upper side of the vehicle body .

  In the fuel tank structure according to claim 1, the capacitance of the fuel reference measurement unit provided along the surface of the filter has a capacitance that changes when the electrode contacts the foreign matter in the fuel that is sucked into the filter by a liquid flow. It is possible to detect and detect foreign matter. At this time, since the foreign matter is located between the filter and the electrode, the contact state between the electrode and the foreign matter can be stably maintained.

Moreover, in the fuel tank structure according to the first aspect, the fuel reference measuring unit is provided along the bottom of the fuel tank, and the filter covers the top thereof, so that the foreign matter that has entered the gap between the electrode and the filter is a liquid flow. Outflow is suppressed, and the contact state between the electrode and the foreign matter can be stably maintained.

According to a second aspect of the present invention , in the fuel tank structure according to the first aspect , the bottom of the fuel tank is provided with a concave portion in which a bottom plate is recessed downward of the vehicle body, and the fuel reference measuring portion is provided in the concave portion. .

In the fuel tank structure according to the second aspect, the fuel reference measurement unit can be covered from the upper side of the vehicle body at a predetermined interval by using a filter having a flat shape on the lower surface of the vehicle body.

The fuel tank structure according to claim 3 is provided in a vehicle, and stores a fuel tank that stores fuel to be sent inside by a fuel tube connected to a delivery means, and a filter that covers a suction port that opens at the tip of the fuel tube. A liquid level sensor having a liquid level measuring unit for measuring the liquid level of the fuel in the fuel tank by electrostatic capacity, and provided on the liquid level sensor, along the upper side surface of the vehicle body of the filter. A fuel reference measurement unit that detects an electrostatic capacity of the fuel with the electrode, and a cover that is provided on the vehicle upper surface of the filter and covers at least a part of the fuel reference measurement unit And a member.

In the fuel tank structure according to claim 3 , the capacitance of the fuel reference measurement unit provided along the surface of the filter is changed by contacting the foreign matter in the fuel attracted to the filter by the liquid flow. It is possible to detect and detect foreign matter. At this time, the liquid flow in the vicinity of the electrode is suppressed by the cover member that covers the electrode of the fuel reference measurement unit provided on the filter. For this reason, it is suppressed that the foreign material which contacts this on an electrode flows out with a liquid flow, and the contact state of an electrode and a foreign material can be maintained stably.

  As described above, the fuel tank structure according to the present invention has an excellent effect that foreign matter can be stably detected using a liquid level sensor.

It is a sectional side view which shows the fuel tank provided with the fuel tank structure which concerns on 1st Embodiment of this invention. It is an expanded sectional side view which shows the fuel tank provided with the fuel tank structure which concerns on 2nd Embodiment of this invention. It is a sectional side view which shows the fuel tank provided with the fuel tank structure which concerns on 3rd Embodiment of this invention. It is an expanded sectional side view which shows the fuel tank provided with the fuel tank structure which concerns on 4th Embodiment of this invention. It is a sectional side view which shows the fuel tank provided with the fuel tank structure which concerns on a comparative example.

  <Structure>

  An example of the fuel tank structure according to the first embodiment of the present invention will be described with reference to FIGS. In the figure, the arrow UP indicates the upward direction of the vehicle body.

  As shown in FIG. 1, in this fuel tank structure, a liquid level sensor 14 is provided inside the fuel tank 10. The liquid level sensor 14 is installed in the vertical direction of the vehicle body and is disposed along the bottom wall 20 of the fuel tank 10 and a liquid level measuring unit 16 that measures (detects) the liquid level (liquid level F) of the fuel. And a reference measurement unit 18.

  The fuel tank 10 is a container having a substantially box shape as shown in FIG. 1, and its shape is determined by the shape of a vehicle body or the like to be installed and the component arrangement. The material of the fuel tank 10 is selected in consideration of resistance to corrosion by fuel (gasoline etc.), mechanical strength, impact resistance and safety in the event of a collision.

  An insertion port 22 is provided on the upper side of the vehicle body of the fuel tank 10, and is sealed with a lid portion 28 that closes the insertion port 22 from the outside so that fuel inside does not leak out. The insertion port 22 protruding in a cylindrical shape in the upward direction of the vehicle body is sealed with a lid portion 28, and the fuel tube 13 communicates with the inside and outside of the fuel tank 10 through the lid portion 28.

  The fuel tank 10 is set to a full tank liquid level (refer to the liquid level F in FIG. 1), thereby restricting the total amount of fuel that enters the fuel tank 10 and securing a vapor layer.

  As shown in FIG. 1, a fuel tube 13 is provided inside the fuel tank 10, and the internal fuel is pumped out by a fuel pump (not shown) connected to the fuel tube 13 and sent out of the fuel tank 10. It is said that.

  Since the tip of the fuel tube 13 is opened and the fuel is sucked by the negative pressure generated by the fuel pump, there is a possibility that foreign matters such as iron powder and silicon contained in the fuel are sucked. In order to avoid a situation in which these foreign substances reach the vaporizer (carburetor), fuel injection device (injection), etc. via the fuel tube 13 and cause problems such as blockage and clogging, the opening at the tip is covered with the filter 12, It is configured to prevent foreign matter from entering the fuel tube 13.

  FIG. 1B is a developed plan view showing the liquid level sensor 14 shown in FIG.

  As shown in this figure, the liquid level sensor 14 has a structure in which an electrode 14D is provided on the surface of a sheet-like base 14C formed of a foldable insulator such as a resin film whose longitudinal direction is the vehicle body. Yes. As an example, the remaining amount of fuel remaining in the fuel tank 10 is detected from the electric capacity that varies depending on the length of the electrode 14D in contact with fuel such as gasoline and the length of the portion in contact with air. To do.

  As a method of electrically measuring (detecting) the liquid level (liquid level height), for example, there is a method of measuring the capacitance between the electrodes 14D. When the fuel in the fuel tank is reduced (eg, exhausted), the space between the electrodes 14D becomes occupied by what was previously occupied by the fuel, so the capacitance decreases. Therefore, by detecting the decrease in the capacitance, it is possible to detect that the fuel in the fuel tank 10 has decreased (for example, the fuel tank 10 has become empty).

  Note that the electrode 14D is not a simple ladder-like wiring, but is arranged in a comb-like shape so that the two electrodes overlap each other as shown in FIG. 1C, and is not electrically connected. The electrode 14D shown in FIG. 1B is formed. The electrode 14D is electrically connected to the outside through a terminal 14E provided at the end of the liquid level sensor 14. For example, the liquid level detected by an electric circuit provided outside is provided outside the fuel tank 10 as fuel amount information. Is transmitted to.

  The liquid level sensor 14 includes a fuel reference measuring unit 18 provided along the bottom wall 20 of the fuel tank 10 and a liquid level measuring unit extending in the vertical direction of the vehicle body so as to cover the liquid level F when the tank is full. 16 is formed so as to form a continuous belt-like member. A fuel reference measurement unit 18 disposed along the bottom wall 20 of the fuel tank 10 is formed by bending the lower end of the vehicle body of the liquid level sensor 14 at L1.

  The liquid level measurement unit 16 is configured to measure the fuel liquid level in the fuel tank 10 in accordance with the change in capacitance between the electrodes 14D as described above. On the other hand, the fuel reference measurement unit 18 is disposed along the bottom wall 20 of the fuel tank 10 as shown in FIG. For this reason, the fuel reference measuring unit 18 measures the capacitance of the fuel while always existing in the liquid of the fuel, and serves as a reference for the capacitance.

  In the fuel reference measurement unit 18, at least a part of the electrode 14 </ b> D facing the upper side of the vehicle body is covered from the upper side of the vehicle body by the filter 12. Specifically, in the fuel reference measurement unit 18, the electrode 14 </ b> D is opposed to the lower surface of the vehicle body of the filter 12 with a predetermined distance d. As a result, the fuel reference measurement unit 18 sandwiches the foreign matter 40 in the fuel between the electrode 14D and the filter 12, and the amount of the foreign matter (the degree of clogging of the filter 12) is reduced by the electrode 14D. It is configured to detect as a change.

  In addition to the fuel reference measurement unit 18, a reference measurement unit provided on the vapor layer (above the full tank liquid level F) is provided to compare the measured values by obtaining a reference for the gas phase capacitance. By doing so, it may be configured to perform more accurate detection.

<Action>

  Next, the operation of this embodiment will be described.

  As shown in FIG. 1A, inside the fuel tank 10, the foreign matter 40 contained in the fuel moves on the surface of the filter 12 while moving by fuel suction by the fuel tube 13 or by fuel swinging due to running of the vehicle. Adsorbed.

  At this time, when the substantially L-shaped liquid level sensor 114 as in the comparative example shown in FIG. 5 is used, the fuel reference measuring unit 118 arranged along the bottom wall 120 of the fuel tank 100 also has the foreign matter 40 or Since the moisture 42 is in contact, it can be detected by a change in electrostatic capacity. However, since the fuel is oscillating and flowing for the reasons described above, the foreign matter 40 and the moisture 42 are also detected by the fuel reference measuring unit 118. Because it moves from above, accurate measurement is difficult.

  In the present embodiment, the above problem is solved by disposing the filter 12 at a predetermined interval d above the vehicle body of the fuel reference measurement unit 18. That is, when the filter 12 sucks the fuel, the foreign matter 40 is also adsorbed on the surface, but the interval d between the fuel reference measurement unit 18 and the filter 12 is kept sufficiently narrow as shown in FIG. Thus, the foreign matter 40 can be retained between the electrode 14D of the fuel reference measurement unit 18 and the filter 12 facing the foreign matter 40, and can be accurately detected by a change in capacitance.

  Further, even when moisture contained in the fuel is condensed, the fuel reference measuring unit 18 along the bottom wall 20 of the fuel tank 10 can detect moisture by a change in capacitance.

Second Embodiment

  FIG. 2 shows an example of a fuel tank structure according to the second embodiment of the present invention. In the figure, the arrow UP indicates the upward direction of the vehicle body. Hereinafter, the same components and members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, a liquid level sensor 14 is provided inside the fuel tank 10. The liquid level sensor 14 is installed in the vertical direction of the vehicle body and measures the liquid level of the fuel (detects the liquid level), and the fuel reference measurement disposed along the bottom wall 20 of the fuel tank 10. Part 18. On the other hand, the bottom wall 20 is provided with a recess 24 that is recessed on the lower side of the vehicle body, and the fuel reference measurement unit 18 is disposed so as to fit into the recess 24.

<Action>

  In the present fuel tank structure, the fuel reference measurement unit 18 is disposed so as to fit into the recess 24. For this reason, it is possible to cover the fuel reference measuring unit 18 from the upper side of the vehicle body with a predetermined distance d by using the filter 12 having a flat shape on the lower side surface of the vehicle body. In other words, the shape (structure) of the filter 12 can be simplified as compared with the first embodiment.

  In addition, the fuel reference measurement unit 18 that is disposed by being fitted in the recess 24 can detect the foreign matter 40 by a change in capacitance as in the first embodiment. In addition, the water 42 in which the water mixed in the fuel is agglomerated sinks and accumulates on the bottom wall 20 because the specific gravity is larger than that of gasoline or the like. For this reason, the fuel tank 10 inevitably gathers at the lowest place in the fuel tank 10, that is, the recess 24.

  At this time, since the fuel reference measurement unit 18 is provided in the recess 24, the water 42 is likely to come into contact with the fuel reference measurement unit 18 as shown in FIG. The reference measurement unit 18 can more easily detect the change in capacitance.

  Further, by adjusting the depth of the recess 24, the size of the distance d between the electrode 14D of the fuel reference measurement unit 18 and the surface of the filter 12 can be set, and at the same time, the lower surface of the vehicle body of the filter 12 is a simple flat surface. Therefore, processing can be facilitated, or a general-purpose filter 12 that is not processed exclusively can be used.

<Third Embodiment>

  FIG. 3 shows an example of a fuel tank structure according to the third embodiment of the present invention. In the figure, the arrow UP indicates the upward direction of the vehicle body. Hereinafter, the same components and members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, a liquid level sensor 14 is provided inside the fuel tank 10. The liquid level sensor 14 is installed in the vertical direction of the vehicle body and measures the liquid level of the fuel (detects the liquid level), and the fuel disposed along the side surface of the filter 12 at the tip thereof. And a reference measurement unit 18.

  In the present embodiment, the fuel reference measurement unit 18 extends in the vertical direction of the vehicle body, is provided along the side surface of the filter 12, and the surface provided with the electrode 14D is disposed to face the filter 12 with a gap d. ing.

<Action>

  As described above, the fuel reference measurement unit 18 extends in the vertical direction of the vehicle body, is provided along the side surface of the filter 12, and the surface provided with the electrode 14D is disposed to face the filter 12 with a gap d. Therefore, if the distance d is sufficiently small, the foreign matter 40 in the fuel enters between the filter 12 and the fuel reference measurement unit 18 and is retained between them. The foreign object 40 can be accurately detected by the change.

  In the present embodiment, since the liquid level sensor 14 itself is used in a flat shape without being bent into an L shape, the number of processing steps can be reduced. However, the distance d is maintained without being deformed in the oscillating fuel. As described later, a method of giving rigidity such as backing with a support member (not shown) or the like may be adopted.

  Further, by using a spacer (not shown) or the like, the size of the distance d between the electrode 14D of the fuel reference measurement unit 18 and the surface of the filter 12 can be set, and at the same time, the side surface of the filter 12 facing the fuel reference measurement unit 18 can be set. Since it can be a simple flat surface, processing is easy, or a general-purpose filter 12 that is not processed exclusively can be used.

  Alternatively, the periphery of the liquid level sensor 14 except for the upper side of the vehicle body may be covered with a cover member to suppress the liquid flow around the liquid level sensor 14. This further promotes the effect that the foreign matter 40 in the fuel enters between the filter 12 and the fuel reference measuring unit 18 and is retained between the two, so that the capacitance change in the fuel reference measuring unit 18 The foreign object 40 can be detected more accurately.

<Fourth embodiment>

  FIG. 4 shows an example of a fuel tank structure according to the fourth embodiment of the present invention. In the figure, the arrow UP indicates the upward direction of the vehicle body. Hereinafter, the same components and members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, a liquid level sensor 14 is provided inside the fuel tank 10. The liquid level sensor 14 is installed in the vertical direction of the vehicle body and measures the liquid level of the fuel (detects the liquid level) 16 and the fuel disposed along the top surface 12P on the vehicle body upper side of the filter 12. And a reference measurement unit 18. On the other hand, a cover member 26 is provided on the top surface 12P so as to cover the fuel reference measurement unit 18, and the fuel reference measurement unit 18 is disposed so as to be covered by the cover member 26.

  The cover member 26 that suppresses the liquid flow is combined with the top surface 12P to form a box that is partially open on the upper side of the vehicle body and provided with an opening 27. The fuel reference measurement unit 18 is inserted into the opening 27. It is configured. That is, the fuel reference measuring unit 18 is provided along the top surface 12P, and the periphery thereof is covered by the cover member 26.

  In the present embodiment, the fuel reference measurement unit 18 is provided along the top surface 12P of the filter 12, but the surface provided with the electrode 14D is not opposed to the filter 12 and is disposed so as to face the vehicle body upward direction. (The same structure as the liquid level sensor 14 of the first and second embodiments is used).

<Action>

  As described above, the surface provided with the electrode 14D of the fuel reference measurement unit 18 is disposed so as not to face the filter 12 and to face in the upward direction of the vehicle body. The foreign matter 40 in the fuel adheres to the surface on which the electrode 14D of the fuel reference measurement unit 18 is provided, such as by riding on a liquid flow caused by suction by the pump.

  If the cover member 26 is not present, the foreign material 40 is pushed away by the liquid flow (arrow FL in the figure) in which the filter 12 sucks the fuel or the fuel swings due to the running of the vehicle, but the cover member 26 prevents the liquid flow. Since the fuel reference measuring unit 18 is covered, the foreign matter 40 once attached to the fuel reference measuring unit 18 is stably retained on the surface. Therefore, the fuel reference measuring unit 18 removes the foreign matter 40 due to a change in capacitance. It can be detected accurately.

  In the present embodiment, it is not necessary to set and maintain the distance d, and the cover member 26 only fixes a simple box-shaped member on the filter 12 and does not require work accuracy. Cost can be reduced.

  Further, in each of the above embodiments, the liquid level measuring unit 16 and the fuel reference measuring unit 18 are made rigid by using a support member (not shown) such as hard plastic separately from the material of the liquid level sensor 14 itself. May be. That is, for example, the liquid level measuring unit 16 and the fuel reference measuring unit 18 are backed by a plate-like support member, so that the liquid level measuring unit 16 can be self-supporting, and at the same time, the liquid level measuring unit 16 and the fuel can be driven by the oscillation of the fuel. It can also be set as the structure which prevents that the reference measurement part 18 deform | transforms and influences a liquid level measurement or a foreign material detection.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. Further, it goes without saying that the scope of rights of the present invention is not limited to these embodiments and can be implemented in various modes without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Fuel tank 12 Filter 13 Fuel tube 14 Liquid level sensor 16 Liquid level measurement part 18 Fuel reference measurement part 20 Bottom wall 22 Insertion port 24 Recess 26 Cover member 28 Cover part 40 Foreign substance 42 Moisture F Liquid surface

Claims (3)

A fuel tank that is provided in the vehicle and stores fuel to be sent out internally by a fuel tube connected to the sending means;
A filter covering a suction port opened at a tip of the fuel tube;
A liquid level sensor having a liquid level measuring unit for measuring the liquid level of the fuel in the fuel tank by electrostatic capacity;
The liquid level sensor is provided along the bottom surface of the fuel tank, has an electrode on the upper surface of the vehicle body, and has an electrode disposed on the surface of the filter so as to keep a predetermined distance therebetween. A fuel reference measuring unit that detects a capacity and is at least partially covered from the upper side of the vehicle body by the filter installed at a predetermined interval ;
With fuel tank structure. 2. The fuel tank structure according to claim 1 , wherein the bottom of the fuel tank is provided with a concave portion in which a bottom plate is recessed downward of the vehicle body, and the fuel reference measuring portion is provided in the concave portion. A fuel tank that is provided in the vehicle and stores fuel to be sent out internally by a fuel tube connected to the sending means;
A filter covering a suction port opened at a tip of the fuel tube;
A liquid level sensor having a liquid level measuring unit for measuring the liquid level of the fuel in the fuel tank by electrostatic capacity;
A fuel reference measurement unit that is provided in the liquid level sensor, is provided along an upper side surface of the vehicle body of the filter and has an electrode on the upper side surface of the vehicle body, and detects a capacitance of fuel by the electrode;
A cover member provided on an upper side surface of the filter body and covering at least a part of the fuel reference measurement unit;
With fuel tank structure.

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