JP5499864B2 - Fuel oxidation detector - Google Patents

Description

  The present invention relates to a fuel oxidation detection device that is provided in a fuel tank and detects the oxidation of fuel in the fuel tank.

  For example, Patent Document 1 discloses a moisture concentration sensor capable of detecting the moisture concentration in the biofuel in the fuel tank in order to detect the oxidative degradation due to the water mixed in the fuel in the fuel tank. Specific examples of the moisture concentration sensor include an optical sensor that detects the moisture concentration based on the light transmittance, and an electromagnetic sensor that detects the moisture concentration based on the electric conductivity of the fuel.

  However, such a sensor requires power supply, and the cost required for detection increases.

JP 2009-13384 A

  In view of the above facts, an object of the present invention is to provide a fuel oxidation detection device capable of detecting fuel oxidation at low cost.

In the first aspect of the present invention, the detecting means is disposed at the bottom of the fuel tank and includes a reaction portion that reacts with an acid contained in water mixed in the fuel, and the reaction portion of the detection means is included in the fuel. Covering means for exposing the moisture mixed in the fuel, and the covering means is formed in a mesh shape with a material whose contact angle with the fuel is larger than the contact angle with the moisture. A mesh member surrounding the reaction portion, and an ion exchange material filling the mesh member and covering the reaction portion, and the detection means is immersed in the ion exchange material. A first electrode member serving as the reaction portion, and a second electrode member serving as the reaction portion formed of a material different from the first electrode member that is immersed in the ion exchange material at a distance from the first electrode member; , The first electric And a potential difference detecting means for detecting a potential difference between the pole member and the second electrode member.
In a second aspect of the present invention, the detection means is disposed at the bottom of the fuel tank and includes a reaction portion that reacts with an acid contained in water mixed in the fuel, and the reaction portion of the detection means is disposed in the fuel. Coating means for covering and exposing the moisture mixed in the fuel, wherein the coating means is made of a water-soluble material and is coated on the reaction portion of the detection means in the fuel And the detection means is configured as a part of the wiring, coated with the coating member, and when the coating member is removed, the reaction part is exposed to the moisture mixed in the fuel and corroded. And a display means for displaying that the exposed portion is disconnected.

In the fuel oxidation detection device according to claim 1 and the fuel oxidation detection device according to claim 2, the reaction part of the detection means reacts with the acid contained in the water mixed in the fuel. Covered with. Therefore, in the fuel, that is, in a state where moisture is not mixed in the fuel, the reaction portion does not react with the acid, and the reaction portion is protected.

  When water is mixed in the fuel, the coating means exposes the reaction part to the mixed water. Therefore, when water contains an acid, the reaction part of the detection means reacts with the acid. By utilizing this, it becomes possible to detect the oxidation of the fuel.

  Thus, in the present invention, it is possible to detect the oxidation of the fuel in the fuel tank at low cost without receiving power supply.

In the invention described in claim 1, the covering means is formed in a mesh shape with a material having a contact angle with the fuel larger than the contact angle with the water, and surrounds the periphery of the reaction portion; An ion exchange material filled in the mesh member and covering the reaction portion.

  Therefore, since the contact angle of the mesh member with the fuel is larger than the contact angle with water, when the fuel exists around the mesh member (no water), the ions inside the mesh member The exchange material does not leak and the fuel does not enter the mesh member. For this reason, alteration (corrosion etc.) of the reaction part of the detection means is suppressed, and the detection means is protected.

  When moisture exists around the mesh member, and the moisture is oxidized and deteriorated, the oxidized and deteriorated substance enters the mesh member so that the ion concentration is equal between the inside and the outside of the mesh member. The oxidation of the fuel in the fuel tank can be detected by a chemical reaction with the detection means.

In the invention according to claim 1, the detection means is separated from the first electrode member as the reaction portion immersed in the ion exchange material and the first electrode member in the ion exchange material. And a second electrode member serving as the reaction portion that is made of a material different from that of the first electrode member, and a potential difference detecting unit that detects a potential difference between the first electrode member and the second electrode member.

  Therefore, when the oxidatively deteriorated substance enters the inside of the mesh member, a battery is formed between the first electrode member and the second electrode member that respectively constitute the reaction portion. By detecting the potential difference between the first electrode member and the second electrode member by the potential difference detection means, the oxidation of the fuel in the fuel tank can be detected.

According to a second aspect of the present invention, the covering means has a coating member made of a water-soluble material and coated on the reaction portion of the detection means in the fuel.

  When moisture is present around the coating member, the coating member is made of a water-soluble material. Therefore, the coating member is dissolved in the moisture, and the reaction part of the detection means is exposed and exposed to moisture. When the fuel oxidizes and the acid dissolves in the water, the reaction part reacts with the acid to corrode and eventually breaks. This can be used to detect the oxidation of the fuel in the fuel tank. .

  In the state where moisture is not present around the coating member, the reaction portion of the detection means is not exposed, so that alteration (corrosion or the like) of the reaction portion of the detection means is suppressed, and the detection means is protected.

In invention of Claim 3 , in the invention of Claim 2 , the said water-soluble material is polyvinyl alcohol.

  Therefore, by appropriately setting the degree of saponification of polyvinyl alcohol, it is possible to adjust the degree of dissolution when immersed in moisture and the degree of insolubility in fuel.

Moreover, in the invention according to claim 2, the detection means is configured as a part of the wiring, coated with the coating member, and exposed to moisture mixed in the fuel when the coating member is removed. It has an exposed part as the reaction part to be corroded and a display means for displaying that the exposed part is disconnected.

  When the coating member is dissolved by the moisture around the coating member, the exposed portion is exposed to the moisture mixed in the fuel and corroded. Since the exposed part is configured as a part of the wiring, if the exposed part (reactive part) is disconnected due to oxidatively deteriorated moisture, this is displayed by the display means, so that the oxidation of the fuel can be known. .

According to a fourth aspect of the invention, in the invention of the second or third aspect , the exposed portion is subjected to corrosion resistance plating.

  Thus, when corrosion-resistant plating is applied to the exposed part, the corrosion rate of the exposed part can be reduced and the time required for disconnection can be lengthened.

In the invention according to claim 5 , in the invention according to claim 4 , the corrosion-resistant plating is locally thinned in a part of the exposed portion.

  As a result, the corrosion rate of the exposed portion can be improved at the portion where the corrosion-resistant plating is locally thin, and the exposed portion can be disconnected in a short time. Note that the portion where the corrosion-resistant plating is thinned may be relatively thinner than other portions, or may be a portion where the corrosion-resistant plating is not completely applied.

  Since the present invention has the above configuration, it is possible to detect the oxidation of the fuel in the fuel tank at a low cost.

It is a schematic sectional drawing which shows the fuel oxidation detection apparatus of 1st Embodiment of this invention with a part of fuel tank in a normal state. It is a schematic sectional drawing which shows the fuel oxidation detection apparatus of 1st Embodiment of this invention with a part of fuel tank in the state in which the water | moisture content exists in the bottom part of a fuel tank. It is a schematic sectional drawing which expands and shows the fuel oxidation detection apparatus of 1st Embodiment of this invention partially in a normal state. It is a schematic sectional drawing which expands partially and shows the fuel oxidation detection device of a 1st embodiment of the present invention in the state where moisture exists in the bottom of a fuel tank. (A)-(C) is explanatory drawing which shows the relationship between the contact angle of the state which the liquid contacted the other party member, and the surface shape of the liquid. It is a schematic sectional drawing which shows the fuel oxidation detection apparatus of 2nd Embodiment of this invention with a part of fuel tank in a normal state. It is a schematic sectional drawing which shows the fuel oxidation detection apparatus of 2nd Embodiment of this invention with a part of fuel tank in the state which the coating member melt | dissolved partially. It is a schematic sectional drawing which shows the fuel oxidation detection apparatus of 2nd Embodiment of this invention with a part of fuel tank in the state in which the signal wire exposed part was disconnected.

  1 and 2 show a fuel oxidation detection device 12 according to a first embodiment of the present invention. 3 and 4 show the fuel oxidation detection device 12 partially enlarged. The fuel oxidation detection device 12 is disposed in the fuel tank. The fuel tank is formed in a substantially box shape from substantially metal or resin, and fuel used in the engine (not shown) is stored inside.

  The fuel oxidation detection device 12 includes an anode member 14P and a cathode member 14M each formed in a plate shape (or rod shape) from different kinds of metals (or carbon). In the present embodiment, in particular, the anode member 14P is made of a material having a positive standard electrode potential, and serves as the first electrode member according to the present invention. The cathode member 14M is made of a material having a negative standard electrode potential and is the second electrode member according to the present invention. One end portions (upper portions in FIGS. 1 and 2) of the anode member 14P and the cathode member 14M are fixed to the casing 16, and the anode member 14P and the cathode member 14M are separated from each other with a predetermined interval (non-contact). State).

  A protective net member 18 is fixed to the casing 16. The protective net member 18 is arranged and shaped so as to enclose the anode member 14P and the cathode member 14M in a space formed between the protective net member 18 and the casing 16. The overall cross-sectional shape of the protective mesh member 18 is substantially U-shaped, and the lower end portion 18 </ b> B is in contact with the bottom portion 20 </ b> B of the fuel tank 20. The lower end portion 18B of the protective mesh member 18 may be separated from the bottom portion 20B of the fuel tank 20.

The protective mesh member 18 is a mesh-like member made of a resin (for example, nylon, polyethylene, polypropylene, etc.) whose contact angle with the oil (fuel) is larger than the contact angle with water, and the mesh according to the present invention. It is an example of a shaped member. In this embodiment, the opening cross-sectional area of the mesh of the protective mesh member 18 is 0.1 cm ² or less.

  Here, FIGS. 5A to 5C show the contact angle θ and the surface shape of the liquid 34 when the liquid 34 (which may be either oil or moisture) contacts the counterpart member 36. The general relationship of is shown. As shown in FIG. 5A, when the contact angle θ is large, the liquid 34 swells in a circular shape on the surface of the counterpart member 36. That is, the counterpart member 36 has water repellency and oil repellency. As shown in FIG. 5B, the liquid 34 spreads on the surface of the counterpart member 36 as the contact angle θ decreases. As shown in FIG. 5C, when the contact angle θ is further small, the liquid 34 wets and spreads over a wide range on the surface of the counterpart member 36, and the counterpart member 36 has hydrophilicity and lipophilicity. ing.

  As shown in FIGS. 3 and 4, the inside of the protective mesh member 18 is filled with an ion exchange material 22, and this ion exchange material 22 exists around the anode member 14P and the cathode member 14M. Yes.

  The anode member 14 </ b> P and the cathode member 14 </ b> M are electrically connected by wiring 24 inside the housing 16. Further, the wiring 24 is extended to the outside of the fuel tank 20 through the casing 16, and a voltmeter 26 which is an example of the potential difference detecting means of the present invention is connected to the extended portion, and the anode member 14P and It is connected so as to detect a potential difference with the cathode member 14M. The potential difference detecting means is not limited to the voltmeter 26, and may be, for example, an analog input terminal of a control computer. Furthermore, a light bulb that emits light when a current flows due to a potential difference may be used.

  Here, the anode member 14P is made of carbon, copper, silver chloride, zinc chloride, copper chloride, or the like, and the cathode member 14M is made of zinc, magnesium, a magnesium alloy, or the like. Further, as the ion exchange material 22, water or gel having an electric conductivity of 10 μs / m or less (for example, distilled water (electric conductivity: 1 to 10 μs / m) or pure water (electric conductivity: 1 μs / m or less)). (Hereinafter, the ion exchange material 22 will be described as the moisture 30 in particular.) Therefore, the ion exchange material 22 contains an anodized ion at a certain concentration or higher (a state in which it is an electrolyte solution). ), A battery is constituted by the anode member 14P, the electrolyte solution (anodized ions), and the cathode member 14M.

  Next, the operation of the fuel oxidation detection device 12 of this embodiment will be described.

  In a normal state, the electric conductivity of the ion exchange material 22 is low (as described above, 10 μs / m or less). Even when the anode member 14P having a positive standard electrode potential and the anode member 14M having a negative standard electrode potential are immersed in the ion exchange material 22 having a sufficiently low electrical conductivity in this manner, A potential difference does not occur between them, and the anode member 14P and the cathode member 14M maintain the original state. In other words, the electrical conductivity of the ion exchange material 22 is set such that no current flows between the anode member 14P and the cathode member 14M, so that the anode member 14P is maintained at a level not oxidized. For example, the deterioration of the anode member 14P and the cathode member 14M is suppressed in a state where there is no fuel in the fuel tank 20 (a state in the air), such as when the fuel tank 20 is assembled to the vehicle body or transported. Can protect.

  Here, when the fuel 32 is supplied into the fuel tank 20, as shown in FIG. 1, the periphery of the fuel oxidation detection device 12 (particularly, the periphery of the protective mesh member 18) is immersed in the fuel 32, and the protective mesh member The inside of 18 is exposed to water and the outside is exposed to fuel 32. Here, since the contact angle between the protective mesh member 18 and the oil is larger than the contact angle with water, the movement (mixing) of liquid does not occur between the inside and the outside of the protective mesh member 18 due to the difference in the contact angle. . That is, as shown also in FIG. 3, the ion exchange material 22 inside the protective mesh member 18 does not leak to the outside of the protective mesh member 18, and the state held inside is maintained.

  The fuel tank 20 normally does not contain moisture, but moisture may be mixed in the fuel tank 20 due to, for example, refueling when it rains or due to the influence of water damage or the like. In addition, water droplets may be condensed on the inner surface of the fuel tank 20. Such moisture is deposited as layer-separated water 28 at the bottom of the fuel tank 20.

  As shown in FIG. 2, due to the layer separation water 28 deposited on the bottom of the fuel tank 20, moisture 30 exists inside and outside the lower part of the protective mesh member 18. That is, since the substances having the same contact angle are in contact with the inside and outside of the protective mesh member 18, as shown in FIG. 30 can come and go.

  When the fuel 32 is oxidized and deteriorated in this state, the acid (anodized ions) is dissolved in the layer-separated water 28 deposited on the bottom of the fuel tank 20 to produce an acidic electrolyte solution. Then, the oxidized and deteriorated substance enters from the outside to the inside of the protective mesh member 18 so that the concentrations of the anodic oxidation ions are equal between the inside and the outside of the protective mesh member 18. That is, the water inside the protective mesh member 18 becomes the electrolyte solution. It is not always necessary for the oxidized and deteriorated substance to enter the inside of the protective net member 18 together with the moisture 30 that moves back and forth between the inside and the outside of the protective net member 18. For example, a substance that has been oxidized and deteriorated due to a difference in the anodized ion concentration between the inside and the outside of the protective mesh member 18 may enter the protective mesh member 18.

  As a result, since the battery is formed between the anode member 14P, the electrolyte solution (anodized ions), and the cathode member 14M inside the protective mesh member 18, the cathode member 14M is made of + (plus) metal. It dissolves while releasing ions into the moisture 30. The released metal ions combine with the anodized material in the moisture 30 and the electrons supplied from the anode member 14P, and are oxidized while releasing hydrogen.

  At this time, as described above, since the battery is configured between the anode member 14P, the electrolyte solution (anodized ions), and the cathode member 14M, in the voltmeter 26, each standard of the anode member 14P and the cathode member 14M. The voltage obtained by adding the electrode potential is measured.

  Thus, in the fuel oxidation detection device 12 of the present embodiment, the oxidative deterioration of the fuel 32 in the fuel tank 20 can be detected with a simple configuration. For example, since it is not necessary to receive a power supply for detection, the oxidation of fuel can be detected at a low cost.

  Further, in the fuel oxidation detection device 12, when a direct current motor (not shown) is disposed in the fuel tank 20, it is possible to suppress the deterioration of the direct current motor. That is, when the DC motor is immersed in the oxidatively deteriorated fuel 32, metal ions are dissolved from the negatively charged portion of the components of the DC motor. There is a concern that a non-conductive film in which the acid in the fuel and this metal ion are combined is formed on the surface of the positive brush which is the positive electrode, resulting in poor conduction of the DC motor.

  However, if the oxidation of the fuel is detected by the fuel oxidation detection device 12, it is possible to take necessary measures before the above-described DC motor conduction failure occurs. For example, the occurrence of a malfunction can be suppressed in advance by replacing the DC motor before it becomes impossible to drive.

  6 to 8 show a fuel oxidation detection device 52 according to a second embodiment of the present invention. In the fuel oxidation detection device 52 of the second embodiment, in the fuel tank system configured to include the fuel tank 20 and accompanying members, the fuel oxidation detection device is used by utilizing a part of the wiring configuring the fuel tank system. 52 is configured. In the following, the fuel oxidation detection device 52 is configured by using a sender gauge signal line 54 that detects the amount of fuel in the fuel tank 20 in particular. For example, the signal line 54 is connected to a display device 62 provided on a panel (not shown) in a vehicle cabin of the vehicle.

  As shown in FIG. 6, the signal line 54 is covered and protected by a covering member 56, but the covering member 56 is partially removed to form a signal line exposed portion 58. The signal line exposed portion 58 is an exposed portion (reactive portion) according to the present invention.

  At least the entire signal line exposed portion 58 and a part of the covering member 56 on both sides thereof are coated with a coating member 60 made of a water-soluble resin. That is, the signal line exposed portion 58 coated with the coating member 60 is disposed at the bottom of the fuel tank 20.

  In the present embodiment, polyvinyl alcohol is used as the coating member 60. Polyvinyl alcohol adjusts the reaction rate (degree of reaction) when immersed in water and the reaction rate (degree of non-reaction) when immersed in fuel by setting the degree of saponification appropriately. Is possible.

  In the fuel oxidation detection device 52 of the second embodiment configured as described above, the coating member 60 is immersed in the fuel 32 in the normal state, that is, when the moisture 30 is not mixed in the fuel tank 20. . As shown in FIG. 6, the coating member 60 made of a water-soluble resin is not affected by the fuel 32, so that the fuel 32 does not contact the signal line exposed portion 58. Therefore, the operation of the sender gauge is not affected.

  When moisture is deposited on the bottom of the fuel tank 20, the coating member 60 reacts with the layer separation water 28 and dissolves as shown in FIG. At this time, the signal line exposed portion 58 is exposed in the layer separated water 28, but when the conductivity of the layer separated water 28 is low, the signal line exposed portion 58 is energized in the layer separated water 28. Is maintained.

  When the fuel 32 is oxidized and deteriorated and the acid is dissolved in the layer separation water 28, the signal line exposed portion 58 is corroded by the acid. When the corrosion progresses, the signal line exposed portion 58 is disconnected as shown in FIG. Since the signal line exposed portion 58 is configured as a part of the signal line 54 of the sender gauge, the disconnection is caused, for example, by the display device 62 on the panel in the passenger compartment being displayed as an abnormality, so The worker can know.

  As described above, in the fuel oxidation detection device 52 of the second embodiment, it is not necessary to receive power supply in order to detect the oxidation of the fuel 32 in the fuel tank 20, and the oxidation of the fuel 32 can be detected at a low cost. Is possible.

  In the second embodiment, the signal line 54 is displayed by opening the fuel filler cap of the fuel tank 20 in a state in which an occupant, a refueling worker, or the like knows the abnormality of the signal line 54 by an abnormality display by the display device 62. , It can be seen that this abnormality display is an abnormality due to the disconnection of the signal line 54. For this reason, it is also known that maintenance such as cleaning of the fuel tank 20 and inspection and replacement of various parts (fuel pump and the like) constituting the fuel tank 20 is necessary as necessary. Further, it is possible to know that the cause of the abnormality display is the disconnection of the signal line 54, that is, the fuel abnormality, and the cause can be easily identified (isolated). In this way, it is possible to reduce the cost (so-called service cost) required, for example, at the time of regular inspection, for example, by simply determining the necessity of maintenance and taking necessary measures.

  In the fuel oxidation detection device 52 of the second embodiment, the signal line exposed portion 58 does not necessarily need to be configured by removing the covering member 56 of the signal line 54 of the sender gauge. That is, the signal line exposed portion 58 may be configured separately from the signal line 54, and the signal line 54 divided into two may be joined (electrically connected) by the signal line exposed portion 58. In this case, the signal line exposed portion 58 does not need to be formed in a linear shape, and can have various shapes such as a plate shape, a rod shape, and a spiral shape.

  Further, the signal line exposed portion 58 may be subjected to corrosion resistance plating. When the corrosion-resistant plating is performed, the corrosion rate is reduced as compared with the configuration without the corrosion-resistant plating, so that the time required for disconnection can be lengthened.

  When performing corrosion-resistant plating, the plating thin film may be locally removed or may be relatively thinner than other portions to provide a so-called scratched portion. Thereby, the corrosion of the scratch becomes a so-called pitting corrosion phenomenon, and the corrosion rate is improved, so that the signal line exposed portion 58 can be broken in a short time.

  In each of the above embodiments, the fuel oxidation detection device is arranged at the bottom of the fuel tank 20, but the position of the fuel oxidation detection device is not limited to this. For example, when the area | region divided by the partition wall and the baffle is provided in a fuel tank, the structure arrange | positioned at the bottom part of this area | region may be sufficient. That is, the fuel oxidation detection device may be disposed in a portion where moisture mixed in the fuel is accumulated.

12 Fuel Oxidation Detection Device 14P Anode Member (Reaction Part, First Electrode Member)
14M cathode member (reaction part, second electrode member)
18 Protective net member 20 Fuel tank 22 Ion exchange material 24 Wiring 26 Voltmeter (potential difference detecting means)
28 Layer separation water 30 Moisture 32 Fuel 52 Fuel oxidation detection device 54 Signal line (wiring)
56 Coating member 58 Signal line exposed part (reactive part, exposed part)
60 Coating member 62 Display device

Claims (5)

A detecting means disposed at the bottom of the fuel tank and including a reactive portion that reacts with an acid contained in water mixed in the fuel;
Coating means for covering the reaction part of the detection means in the fuel and exposing the moisture mixed in the fuel;
Equipped with a,
The covering means comprises:
A mesh member formed in a mesh shape with a material having a contact angle with the fuel larger than the contact angle with the moisture and surrounding the reaction portion;
An ion exchange material filled in the mesh member and covering the reaction portion;
Have
The detection means is
A first electrode member as the reaction part immersed in the ion exchange material;
A second electrode member as the reaction portion, which is immersed in the ion exchange material away from the first electrode member and is made of a material different from the first electrode member;
A potential difference detecting means for detecting a potential difference between the first electrode member and the second electrode member;
A fuel oxidation detection device. A detecting means disposed at the bottom of the fuel tank and including a reactive portion that reacts with an acid contained in water mixed in the fuel;
Coating means for covering the reaction part of the detection means in the fuel and exposing the moisture mixed in the fuel;
Equipped with a,
The covering means comprises:
A coating member made of a water-soluble material and coated on the reaction portion of the detection means in the fuel;
The detection means is
An exposed portion as the reaction portion that is configured as a part of the wiring and is coated with the coating member and exposed to moisture mixed with the fuel when the coating member is removed;
Display means for displaying that the exposed portion is disconnected;
A fuel oxidation detection device. The fuel oxidation detection device according to claim 2 , wherein the water-soluble material is polyvinyl alcohol. The fuel oxidation detection device according to claim 2 or 3 , wherein the exposed portion is subjected to corrosion-resistant plating. The fuel oxidation detection device according to claim 4 , wherein the corrosion-resistant plating is locally thinned in a part of the exposed portion.

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