Fuel property determination device and fuel supply device

Abstract

To provide a technology that detects the presence or absence of water contamination in fuel and the type of fuel using a simple configuration.SOLUTION: A fuel property determination device 20 is provided in a fuel supply path 3 into which fuel flows. The fuel property determination device 20 irradiates the fuel in the fuel supply path 3 with terahertz waves and determines the presence or absence of water contamination in the fuel and the type of fuel from received signals of the terahertz waves received through the fuel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a fuel property determination device that determines the property of fuel and a fuel supply device. [Background technology]

[0002] Patent Document 1 discloses a fuel supply system that supplies fuel to a vehicle via a fuel supply path and a nozzle, and includes a water detection sensor that determines whether water is mixed in the fuel flowing through the fuel supply path. Patent Document 2 discloses a fuel supply system that supplies fuel to a vehicle via a fuel supply path and a nozzle, and includes an oil type sensor that determines the type of fuel flowing through the fuel supply path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-85124 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-76741 Summary of the Invention [Problem to be solved by the invention]

[0004] The water detection sensor disclosed in Patent Document 1 measures the water content of fuel based on a received signal of terahertz waves that have passed through the fuel. In contrast, the oil type sensor disclosed in Patent Document 2 determines the type of fuel based on a detection signal of the oil vapor concentration of the fuel. As described above, in conventional technology, the presence or absence of water in fuel and the type of fuel are detected based on different signals. Therefore, in order to determine the presence or absence of water in fuel and the type of fuel (fuel properties), both a water detection sensor and an oil type sensor are required. This results in a problem of an increased number of sensors being installed in the fuel supply path, and a complex structure for installing each sensor in the fuel supply path.

[0005] An object of one embodiment of the present invention is to provide a fuel property determining device and a fuel supply device that can detect both the presence or absence of water in fuel and the type of fuel using a simple configuration. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a fuel property determining device according to one embodiment of the present invention is provided in a fuel supply path into which fuel flows, irradiates terahertz waves onto the fuel in the fuel supply path, and determines the presence or absence of water contamination in the fuel and the type of fuel from a received terahertz wave signal received through the fuel.

[0007] One embodiment of the present invention is a fuel supply system including a fuel supply path through which fuel flows, a control means for stopping the fuel supply, and a memory unit in which a type of fuel previously set for the fuel supply path is stored. The fuel supply path is provided with a fuel property determination device that irradiates terahertz waves onto the fuel in the fuel supply path and determines the presence or absence of water in the fuel and the type of fuel from a received terahertz wave signal received through the fuel. If the fuel property determination device determines that water is present in the fuel or that the type of fuel is different from that stored in the memory unit, the control means stops the fuel supply. [Effects of the Invention]

[0008] According to one embodiment of the present invention, it is possible to detect both the presence or absence of water in fuel and the type of fuel using a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating a configuration of a fuel tanker according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of the fuel property determining device in FIG. 1. [Figure 3] 10 is a characteristic diagram showing the relationship between the frequency of an electrical signal on the terahertz wave receiving side and the received signal level. [Figure 4]2 is a flowchart showing a control process for fuel supply by the fuel tanker in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel property determining device and a fuel supply device according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0011] 1 schematically shows a refueling machine 1 as a fuel supply device. The refueling machine 1 is equipped with, for example, one refueling system. Note that the refueling machine 1 may be equipped with multiple refueling systems. The refueling machine 1 is equipped with a refueling machine housing 2, a fuel supply passage 3, a refueling control device 16, a fuel property determination device 20, etc.

[0012] The fuel tanker housing 2 is a fuel supply device housing, and has a display 14 on its front surface. A fuel supply path 3 is provided inside the fuel tanker housing 2. The fuel supply path 3 is provided with a pump 4 as a liquid delivery device, a flow meter 7 as a flow rate measuring device, and a control valve 9 as control means.

[0013] One end of the fuel supply line 3 is connected to an extension pipe 91 extending from a storage tank 90 provided underground, and is in communication with the storage tank 90. ​​The other end of the fuel supply line 3 is connected to the base end of a fuel filler hose 10 extending from the fuel dispenser housing 2, and is in communication via the fuel filler hose 10 with a fuel filler nozzle 11 provided at the tip of the hose. In this case, vehicle fuel such as regular gasoline, premium gasoline, or diesel, or lighting fuel such as kerosene, is stored in the storage tank 90.

[0014] Pump 4 is driven by pump drive motor 5 and pumps up fuel stored in storage tank 90. ​​A pump drive circuit 6 is provided between pump drive motor 5 and a pump drive power supply (not shown). Pump drive circuit 6 supplies a motor drive current from the pump drive power supply to pump drive motor 5 based on a pump drive signal from fuel supply control device 16.

[0015] The flow meter 7 measures the amount of liquid fuel sent from the pump 4 to the fuel supply nozzle 11 via the fuel supply hose 10 by driving the pump drive motor 5. The flow meter 7 is provided with a flow rate transmitter 8. The flow rate transmitter 8 generates a flow rate pulse corresponding to the flow of fuel for each predetermined unit flow rate (for example, 0.01 L), and outputs a flow rate pulse signal corresponding to the amount of liquid fuel measured by the flow meter 7.

[0016] The opening and closing of the control valve 9 is controlled by a fuel supply control device 16. When the control valve 9 is open, fuel supply from the pump 4 to the fuel supply nozzle 11 is permitted. When the control valve 9 is closed, fuel supply from the pump 4 to the fuel supply nozzle 11 is stopped. Therefore, the control valve 9 and the fuel supply control device 16 constitute a control means for stopping the fuel supply.

[0017] The fuel nozzle 11 is equipped with a valve mechanism (not shown) that opens or closes in response to the operation of an operating lever. This valve mechanism is an automatic valve-closing mechanism that closes the valve when the fuel oil level in the target vehicle, such as a vehicle, reaches the discharge pipe at the tip of the nozzle, regardless of the operating position of the operating lever. The fuel nozzle 11 can be removed from and stored in a nozzle hanger 12 provided in the fuel dispenser housing 2. The fuel nozzle 11 is stored in the nozzle hanger 12 while no refueling operation (fuel supply operation) is being performed, in other words, during non-operation and standby periods. The nozzle hanger 12 is provided with a nozzle switch 13 that detects whether the fuel nozzle 11 is removed from or stored in the nozzle hanger 12. The nozzle switch 13 outputs a nozzle detection signal in response to the removal or storage of the fuel nozzle 11.

[0018] The display 14 is provided in the fuel tanker housing 2 with its display surface facing the outside of the fuel tanker housing 2. Display data for various information, including the amount of fuel dispensed, is input to the display 14 from the fuel dispenser control device 16.

[0019] The fuel dispenser housing 2 is also provided with an alarm 15 that alerts the user to the occurrence of an abnormality when the water content Rw of the fuel dispensed from the fuel dispenser nozzle 11 to the object to be supplied is outside the allowable range or when the type of fuel differs from a preset type. The alarm 15 is constituted by, for example, a buzzer, and an alarm generation signal corresponding to various types of alarm information is supplied from the fuel dispenser control device 16.

[0020] The refueling control device 16 is provided inside the refueling machine housing 2. The refueling control device 16 constitutes a liquid supply control unit, controls the execution of fuel supply operations to a supply target such as a vehicle, and calculates the amount of fuel liquid supplied to the supply target for each operation, i.e., the so-called fuel supply amount (liquid supply amount). In response to a nozzle detection signal input from the nozzle switch 13, the refueling control device 16 opens the control valve 9 and outputs a pump drive signal to the pump drive circuit 6. As a result, the refueling control device 16 controls the drive of the pump drive motor 5 and controls the liquid delivery of the pump 4. In addition, the refueling control device 16 calculates the amount of fuel liquid supplied to the supply target, i.e., the so-called fuel supply amount, based on a flow rate pulse signal input from the flow rate transmitter 8, and displays it on the display 14.

[0021] The refueling control device 16 is connected to a fuel property determination device 20. If the fuel property determination device 20 determines that water has been mixed into the fuel or that the type of fuel is different from that stored in memory 27 (storage unit), the refueling control device 16 closes the control valve 9. As a result, the control valve 9 stops the fuel supply when an abnormality occurs in the fuel.

[0022] The fuel supply control device 16 is configured by, for example, a computer device equipped with a microprocessor, memory, interface, etc. The fuel supply control device 16 is also communicatively connected to a gas station LAN (SS-Local Area Network), which is a network connection of gas station devices such as fuel dispensers, point-of-sale information management devices, and fuel supply management devices.

[0023] Next, the fuel property determining device 20 applied to the fuel tanker 1 will be described.

[0024] The fuel property determination device 20 includes a fuel property detection sensor 21 and a fuel property detection processing device 26. The fuel property determination device 20 is provided in a fuel supply path 3 (fuel supply route) into which the fuel flows, and irradiates terahertz waves onto the fuel in the fuel supply path 3, and determines the presence or absence of water contamination in the fuel and the type of fuel from the received terahertz wave signal received via the fuel.

[0025] Fuel property detection sensor 21 is provided inside fuel dispenser housing 2 on the outflow side of flow meter 7 in fuel supply line 3. Specifically, fuel property detection sensor 21 is attached to a pipe on the secondary side of pump 4 in fuel supply line 3. Fuel property detection sensor 21 includes terahertz wave transmitter 22 that oscillates and outputs terahertz waves, and terahertz wave receiver 24 that receives the terahertz waves output from terahertz wave transmitter 22.

[0026] Fig. 2 is a cross-sectional view schematically showing a portion of the fuel supply passage 3 provided with the fuel property detection sensor 21 in the fuel dispenser 1 of this embodiment. As shown in Fig. 2, the fuel property detection sensor 21 is detachably and gas-tightly fixed to a sensor mounting portion provided in the fuel supply passage 3 through which fuel to be supplied to a supply target flows, with the terahertz wave transmitter 22 and the terahertz wave receiver 24 arranged with their transmitting and receiving surfaces facing each other at a predetermined distance.

[0027] The terahertz wave receiving unit 24 includes an RTD receiver (not shown) configured with a terahertz wave resonant tunneling diode or the like, and has the function of receiving and detecting terahertz waves of a predetermined frequency.

[0028] When terahertz wave resonant tunneling diodes are applied to terahertz wave transmitter 22 and terahertz wave receiver 24, separators 23 and 25 of terahertz wave transmitter 22 and terahertz wave receiver 24, respectively, serve as a terahertz wave emitting end face of terahertz wave transmitter 22 and a terahertz wave incident end face of terahertz wave receiver 24, in relation to the fuel present in fuel supply path 3. Separators 23 and 25 prevent terahertz wave transmitter 22 and terahertz wave receiver 24 from coming into contact with the supplied fuel.

[0029] Terahertz waves (radio waves) pass through resin. For this reason, the transmitting surface of terahertz wave transmitter 22 and the receiving surface of terahertz wave receiver 24 are partially provided with separators 23, 25 made of a resin material rather than metal piping. Separators 23, 25 are made of a material that transmits terahertz waves and does not deform, swell, dissolve, or otherwise deteriorate when in contact with fuel and water. In addition, considering the fuel temperatures in various environments in which refueling aircraft 1 is used, it is desirable that separators 23, 25 be made of a material that is heat-resistant, for example, from -20°C to 40°C. As such a material, for example, a fluororesin material can be used as the entire material for separators 23, 25.

[0030] As an example, ethylene tetrafluoroethylene (hereinafter referred to as ETFE) and a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene (PFA) can be used as fluororesins applicable to the separators 23 and 25. Note that the fluororesins applicable to the separators 23 and 25 are not limited to the above examples, and any material may be used as long as it has predetermined terahertz wave transmittance, oil resistance, water resistance, and heat resistance, and the moisture content Rw can be determined.

[0031] Separators 23, 25 may be configured by using a terahertz wave-transmitting material such as glass or quartz as a substrate and coating the surface with fluororesin, instead of forming the entire separators 23, 25 from a fluororesin material. In this case, the terahertz wave-transmitting material may be a material that can transmit terahertz waves sufficiently without attenuation to enable measurement of the target water content Rw (for example, discrimination between Rw<2%, 2%≦Rw<5%, and Rw≧5%).

[0032] In the fuel dispenser 1 of this embodiment, the fuel property detection sensor 21 outputs terahertz waves with a wavelength of 3 mm to 300 μm (frequency of 0.1 THz to 1.0 THz) from the terahertz wave transmitter 22 and receives them from the terahertz wave receiver 24. The wavelength of the terahertz waves (3 mm to 300 μm) is equivalent to or significantly longer than the particle diameter (approximately 200 to 300 μm) of water bubbles and gas bubbles that occur in the fuel liquid when the fuel is dispensed at such a high flow rate and high discharge. Therefore, the terahertz waves are hardly affected by scattering caused by water bubbles and gas bubbles that occur in the fuel liquid when the fuel is dispensed at such a high flow rate and high discharge. Therefore, the fuel dispenser 1 of this embodiment can accurately measure the water content Rw of the fuel even when the fuel is dispensed at a high flow rate and high discharge.

[0033] The travel distance of the terahertz waves in the fuel liquid, i.e., the length of the passage through which the terahertz waves propagate in the fuel supply path 3, is set in consideration of the amount of attenuation of the propagating terahertz waves, the amount of terahertz waves absorbed by water and fuel, etc. By appropriately setting the length of the passage through which the terahertz waves propagate in the fuel supply path 3, it becomes possible to detect with high accuracy whether the water content Rw is within an allowable level (Rw≦2% (predetermined value R0)).

[0034] Although not shown, collimating lenses may be disposed between terahertz wave transmitter 22 and separator 23, and between terahertz wave receiver 24 and separator 25. Disposing a collimating lens increases the reception intensity of the terahertz waves at the RTD receiver in terahertz wave receiver 24, allowing terahertz waves to be emitted from terahertz wave transmitter 22 at a greater distance with a higher intensity. If the reception intensity of the terahertz waves in terahertz wave receiver 24 is sufficiently high and the water content Rw can be quantified, a collimating lens need not be used.

[0035] The fuel property detection processing device 26 is connected to the fuel property detection sensor 21. The fuel property detection processing device 26 controls the operation of the terahertz wave transmitter 22 and the terahertz wave receiver 24 of the fuel property detection sensor 21. Terahertz waves (radio waves) are attenuated (absorbed) by the fuel oil passing through the fuel supply path 3. The fuel property detection processing device 26 constantly monitors the amount of attenuation of the terahertz waves.

[0036] The fuel property detection processing device 26 measures the water content Rw of the fuel supplied to the supply target via the fuel supply path 3 based on the terahertz wave reception signal received by the terahertz wave receiving unit 24. The fuel property detection processing device 26 determines whether water is present in the fuel that is delivered from the pump 4 via the flow meter 7 toward the fuel filler hose 10 and the fuel filler nozzle 11. In addition, the fuel property detection processing device 26 determines the type of fuel based on the terahertz wave reception signal received by the terahertz wave receiving unit 24.

[0037] The fuel property detection processing device 26 is configured by a computer device equipped with, for example, a microprocessor, a memory 27 (storage unit), an interface, etc. The memory 27 stores a fuel type preset for each pump 4 (fuel supply line 3). The fuel property detection processing device 26 determines whether water is mixed in the fuel and the fuel type, and outputs the determination results to the refueling control device 16. The refueling control device 16 controls the pump 4, control valve 9, display 14, alarm 15, etc. in accordance with the fuel determination results output from the fuel property detection processing device 26.

[0038] Next, a method for determining the presence or absence of water contamination and the fuel type in the fuel property detection processing device 26 will be described. FIG. 3 shows the relationship between the frequency of the electrical signal on the terahertz wave receiving side and the received signal level (received signal strength), i.e., the received signal strength of the electrical signal transmitted from the terahertz wave receiving unit 24 to the fuel property detection processing device 26 (circuit). (The terahertz waves received by the terahertz wave receiving unit 24 are output as an electrical signal to the fuel property detection processing device 26 and amplified by an amplifier circuit (not shown).) Specifically, FIG. 3 shows the peak value (maximum value) of the received signal level of the terahertz waves over a predetermined time period. The fuel property detection processing device 26 determines the presence or absence of water contamination and the fuel type from the peak value of the signal level (received signal level) of the electrical signal transmitted from the terahertz wave receiving unit 24. At this time, the peak value of the received signal level varies depending on the water content (0% to 5%) in the fuel and the fuel type. The predetermined time period is set to, for example, about one second. The predetermined time is the time at which the peak value of the received signal level of the terahertz waves becomes different depending on whether water is mixed in and the type of fuel, and is set appropriately based on, for example, actual measurement results.

[0039] Specifically, when the fuel is diesel and no water is mixed in (water content 0%), the peak value of the received signal level of the terahertz waves is the value at point A in Figure 3. When the fuel is diesel and water is mixed in (water content 5%), the peak value is the value at point A' in Figure 3. In other words, when water is mixed in the fuel, the peak value of the received signal level of the terahertz waves decreases, and the water content can be measured from the rate of decrease. More specifically, for every 1% increase in water content, the peak value of the received signal level decreases by a predetermined rate (for example, 3 dBV). From this, the water content can be measured based on the decreased peak value of the received signal level.

[0040] Furthermore, when the fuel is gasoline and no water is mixed in (water content 0%), the peak value of the received terahertz wave signal level is the value at point B in FIG. 3. When the fuel is gasoline and water is mixed in (water content 5%), the peak value is the value at point B' in FIG. 3. In this case, as in the case of diesel fuel, the peak value decreases by a predetermined rate (e.g., 3 dBV) depending on the water content, and the water content can be measured from this rate of decrease. Furthermore, when the fuel is diesel fuel and when the fuel is gasoline, the peak value of the received signal level when no water is mixed in (water content 0%) differs, and this difference can also be used to determine the type of fuel. Furthermore, the relationship regarding the change in the received signal level (intensity) depending on the presence or absence of water and the type of fuel, as shown in FIG. 3, is pre-stored, for example, in memory 27. Therefore, the fuel property detection processing device 26 determines whether water is mixed in and the type of fuel from the relationship regarding the change in the received signal level (intensity) depending on the presence or absence of water mixed in and the type of fuel stored in the memory 27, and from the received signal level of the terahertz waves received by the terahertz wave receiving unit 24.

[0041] Next, the control process for fuel supply by the fuel dispenser 1 of this embodiment will be described with reference to Fig. 4. Note that the steps in the flowchart shown in Fig. 4 are each designated by the letter "S", for example, step 1 is designated as "S1".

[0042] In S1, the fuel supply control device 16 determines whether or not the fuel supply nozzle 11 has been removed from the nozzle hanger 12 based on a nozzle detection signal from the nozzle switch 13. If it detects that the fuel supply nozzle 11 has been removed, it determines "YES" in S1 and proceeds to S2. As long as it determines that the fuel supply nozzle 11 has not been removed, it repeats the processing of S1.

[0043] In S2, the fuel supply control device 16 identifies the fuel supply nozzle 11 that has come off the nozzle hanger 12, and identifies the pump 4 that corresponds to this fuel supply nozzle 11. At this time, the memory 27 has pre-stored therein the type of fuel that corresponds to the pump 4. Therefore, the fuel supply control device 16 reads the type of fuel that corresponds to this pump 4 from the memory 27 to the fuel property detection processing device 26. In S3, the fuel supply control device 16 transmits a pump drive signal to the pump drive circuit 6 to drive the pump 4.

[0044] In S4, the fuel supply control device 16 uses the fuel property detection sensor 21 to measure the signal strength of the terahertz waves that have passed through the fuel flowing through the fuel supply path 3. Specifically, the fuel property detection processing device 26, based on a command signal from the fuel supply control device 16, drives the terahertz wave transmitter 22 to transmit terahertz waves, and measures the signal strength (received signal level) of the radio waves (terahertz waves) received by the terahertz wave receiver 24.

[0045] In S5, the fuel property detection processing device 26 determines whether the fuel is of a different oil type or contains water (normal) based on the signal intensity of the terahertz waves that have passed through the fuel. Specifically, the fuel property detection processing device 26 converts the received terahertz wave signal into a voltage signal corresponding to the received terahertz wave intensity and calculates the difference ΔV between the converted voltage signal (level) and a standard value. The fuel property detection processing device 26 determines whether the fuel is normal based on whether this difference ΔV is equal to or greater than a first predetermined value V1. More specifically, the standard value is a received signal level (peak value of the voltage signal (level)) for the oil type corresponding to the pump 4 that is stored in advance in the memory 27. If there is a predetermined change (e.g., −3 dBV or more) in the received signal level from this standard value, the fuel property detection processing device 26 determines that the fuel type is different or that water has been mixed in the fuel.

[0046] 3, let us suppose that the standard value for the received signal level for diesel (water content 0%) is −61 dBV, the standard value for the received signal level for gasoline (water content 0%) is −65 dBV, and the rate of decrease in the received signal level for water (for every 1% water content) is −3 dBV. The first predetermined value V1 is set to, for example, ±3 dBV as the value of the difference ΔV that allows for determining differences in oil type and the presence of water.

[0047] If the difference ΔV in the received signal levels is equal to or greater than the first predetermined value V1, the fuel property detection processing device 26 determines that the fuel is of a different oil type or that there is a possibility of water contamination. If the fuel is determined to be abnormal in this way, the fuel property detection processing device 26 determines "YES" in S5 and proceeds to S8. On the other hand, if the difference ΔV in the received signal levels is smaller than the first predetermined value V1, the fuel property detection processing device 26 determines that the fuel is of the correct oil type, is not contaminated with water, and is normal. If the fuel is determined to be normal, the fuel property detection processing device 26 determines "NO" in S5 and proceeds to S6.

[0048] S5 merely determines whether the fuel is normal, and whether it is mixed with water or oil is determined later in the flow. In other words, the determination process in S5 triggers a specific determination of whether water or a different type of oil has been mixed in. Furthermore, whether the fuel is normal or not is determined based on the difference between the signal strength and a predetermined level. Therefore, if there is any change in the signal strength in S5, it is assumed that an abnormality may have occurred, and the process proceeds to S8.

[0049] In S6, the refueling control device 16 determines whether refueling has finished. Specifically, the refueling control device 16 determines whether the refueling nozzle 11 has been hung on the nozzle hanger 12 based on a nozzle detection signal from the nozzle switch 13. If it is determined that the refueling nozzle 11 has been hung, that is, if it is determined that refueling has finished, the determination in S6 is "YES" and the process proceeds to S7. In S7, the refueling control device 16 stops the pump 4 and ends the process.

[0050] On the other hand, if it is determined that the fuel nozzle 11 is not open, i.e., if it is determined that refueling has not been completed, the result in S6 is "NO", and the process returns to S4, where it is determined whether the fuel is of a different oil type or whether water has been mixed in (normal).

[0051] In S8, the fuel property detection processing device 26 determines whether the fluctuation range of the intensity of the received terahertz wave signal over a predetermined time period exceeds a second predetermined value V2. If the fluctuation range of the intensity of the received terahertz wave signal over a predetermined time period is large and exceeds the second predetermined value V2, the determination in S8 is "YES" and the process proceeds to S17. If the fluctuation range of the intensity of the received terahertz wave signal over a predetermined time period is small and does not exceed the second predetermined value V2, the determination in S8 is "NO" and the process proceeds to S9.

[0052] Specifically, since terahertz waves are easily absorbed by water, the signal strength of the terahertz waves decreases when water is mixed into the fuel. Therefore, when water is mixed into the fuel, the intensity of the received terahertz wave signal fluctuates more significantly over a given time period than when water is not mixed into the fuel. In this case, when water is mixed into the fuel, the fluctuation range of the received terahertz wave signal level over a given time period is larger than when water is not mixed into the fuel. On the other hand, when the fuel is different from a predetermined oil type or when a different oil type is mixed in, although the received terahertz wave signal level fluctuates depending on the oil type, the fluctuation range of the received signal level over a given time period is smaller than when water is mixed in.

[0053] That is, when water is mixed into fuel, the fluctuation range of the received signal level of the terahertz waves becomes larger than when a different type of oil is mixed into the fuel. S8 utilizes this fact to determine whether the fuel is mixed with water or mixed oil with a different type of oil. For this reason, the magnitude (absolute value) of the second predetermined value V2 is set to a value (|V2|>|V1|) that is larger than the magnitude (absolute value) of the first predetermined value V1 and is a value of the received signal level that can distinguish between mixed oil and water (for example, ±6 dBV).

[0054] Therefore, if the fluctuation range of the received signal level of the terahertz waves exceeds the second predetermined value V2, it is considered that water is mixed into the fuel, so the determination in S8 is "YES" and the process proceeds to S17.

[0055] On the other hand, if the fluctuation range of the received terahertz wave signal level is smaller than the second predetermined value V2, it is considered that the fuel oil type is different from the preset one or a different oil type has been mixed into the fuel. Therefore, the determination in S8 is "NO" and the process proceeds to S9.

[0056] In S17, the fuel property detection processing device 26 calculates the water content Rw from the signal intensity of the terahertz waves and proceeds to S18. Here, as shown in FIG. 3, the water content versus the signal intensity (received signal level) of the terahertz waves is pre-stored in the memory 27. FIG. 3 shows an example of the received signal level of the terahertz waves for fuels with different water contents Rw. Therefore, the fuel property detection processing device 26 compares the received signal level stored in the memory 27 with the received signal level of the terahertz waves to calculate the water content Rw. Specifically, for example, assuming that the received signal level of the terahertz waves decreases by 3 dBV for every 1% water content, the fuel property detection processing device 26 calculates four water contents: 2%, 3%, 4%, and 5% or more. The water contents calculated in S17 may be stored in the memory 27 together with the date and time of the calculation.

[0057] In S18, the fuel property detection processing device 26 determines whether the water content Rw is equal to or less than a predetermined value R0. At this time, the predetermined value R0 is set to the allowable limit value of the water content Rw. Specifically, the predetermined value R0 is set to, for example, 2% (R0=2%).

[0058] If it is determined that the water content Rw exceeds the predetermined value R0 (Rw>R0), the result of S18 is "NO." At this time, the fuel property detection processing device 26 outputs the determination result to the refueling control device 16, and the process proceeds to S19. In S19, the refueling control device 16 stops the pump 4. In S20, the refueling control device 16 causes the display 14 to notify the detection of water, and ends the process. This allows an attendant to respond to the customer, perform water removal work, etc.

[0059] Furthermore, if it is determined that the moisture content Rw is equal to or less than the predetermined value R0 (Rw≦R0), it is considered that the moisture content Rw is within a range in which fuel supply can be continued. Therefore, if it is determined that the moisture content Rw is equal to or less than the predetermined value R0, the determination in S18 is "YES," the moisture content Rw is determined to be within an allowable value, and the process proceeds (returns) to S6.

[0060] Meanwhile, in S9, it is determined how much the received signal level of the terahertz waves differs from the signal level corresponding to the oil type previously set in the pump 4. If this difference ΔV in the received signal level is large and equal to or greater than a third predetermined value V3, it is considered that a different oil type itself or a different oil type has been mixed in beyond the allowable range. For this reason, the third predetermined value V3 is set to a signal level difference ΔV that can determine whether the oil mixture is at a level that is acceptable. In this case, the magnitude (absolute value) of the third predetermined value V3 is set to a value that is greater than the magnitude (absolute value) of the first predetermined value V1 and smaller than the magnitude (absolute value) of the second predetermined value V2 (for example, ±4 dBV) (|V1|<|V3|<|V2|).

[0061] If the difference ΔV in the received signal levels is equal to or greater than the third predetermined value V3, it is considered that fuel mixing has occurred beyond the allowable range, such as when diesel fuel is supplied even though gasoline is set. Therefore, the determination in S9 is "YES" and the process proceeds to S14. In S14, the fuel supply control device 16 stops the pump 4. In S15, the fuel supply control device 16 stores the current data in the memory 27 of the fuel property detection processing device 26. At this time, the current data includes not only the mixing rate of a different fuel type but also the date and time when it was recorded. This data may be stored in the memory of the fuel supply control device 16. In S16, the fuel supply control device 16 notifies the display 14 that the fuel is of a different type and ends the process. This allows the attendant to handle the customer, perform tasks such as changing the type of fuel.

[0062] If the difference ΔV in the received signal levels is smaller than the third predetermined value, it is considered that a different type of oil has been mixed in, but the mixture is within an acceptable range. Therefore, the determination in S9 is "NO" and the process proceeds to S10. In S10, the refueling control device 16 determines whether refueling has been completed. Specifically, the refueling control device 16 determines whether the refueling nozzle 11 has been hung on the nozzle hanger 12 based on the nozzle detection signal from the nozzle switch 13. If it is determined that the refueling nozzle 11 has not been hung, that is, if it is determined that refueling has not been completed, the determination in S10 is "NO" and the process returns to S4, where it is determined whether the fuel is a different type of oil or whether water has been mixed in (normal).

[0063] If it is determined that the refueling nozzle 11 has been closed, that is, if it is determined that refueling has ended, the determination in S10 is "YES" and the process proceeds to S11. In S11, the refueling control device 16 stops the pump 4. In S12, the refueling control device 16 stores the current data in the memory 27 of the fuel property detection processing device 26. At this time, the current data includes the mixing rate of different oil types as well as the date and time when the data was recorded. Note that this data may be stored in the memory of the refueling control device 16. In S13, the refueling control device 16 uses the display 14 or the alarm 15 to notify that the fuel needs to be checked, and ends the process.

[0064] Thus, according to this embodiment, the fuel property determining device 20 is provided in the fuel supply path 3 (fuel supply route) into which the fuel flows, irradiates terahertz waves onto the fuel in the fuel supply path 3, and determines the presence or absence of water in the fuel and the type of fuel from a received signal of the terahertz waves received through the fuel. Specifically, the fuel property determining device 20 determines the presence or absence of water in the fuel and the type of fuel using a single fuel property detection sensor 21.

[0065] Terahertz waves (radio waves) are attenuated (absorbed) by the fuel oil passing through the fuel supply path 3. The fuel property detection processing device 26 constantly monitors the amount of attenuation of the terahertz waves. The amount of attenuated radio waves (amount of attenuation) varies depending on the type of fuel oil. Terahertz waves (radio waves) are most easily transmitted through the following materials in order: air > diesel > gasoline > water. The magnitude of the received signal level output from the terahertz wave receiving unit 24 to a determination circuit (not shown) of the fuel property detection processing device 26 also increases or decreases depending on the signal strength of the received terahertz waves.

[0066] Therefore, the relationship between the signal strength of the terahertz waves and the oil type (data obtained through testing) is stored in advance in the memory 27. The fuel property detection processing device 26 compares the received signal level (signal strength) of the measured terahertz waves with the received signal level (signal strength) of the oil type stored in the memory 27 to determine whether the oil type is compatible with the pump 4.

[0067] The memory 27 also stores in advance the relationship between the signal strength of the terahertz waves and the water content (data obtained through testing) as shown in Fig. 3. The fuel property detection processing device 26 calculates the water content Rw by comparing the measured reception signal level (signal strength) of the terahertz waves with the reception signal level (signal strength) stored in the memory 27. The fuel property detection processing device 26 determines whether water is mixed in the fuel based on the calculated water content Rw.

[0068] In this way, the fuel property determining device 20 can determine the presence or absence of water in the fuel and the type of fuel from the received signal of the terahertz waves transmitted into the fuel. Therefore, there is no need to provide a water contamination determining device and a fuel type determining device separately. As a result, there is no need to provide multiple sensors in the fuel supply path 3, etc., and both the presence or absence of water in the fuel and the type of fuel can be detected using a simple configuration.

[0069] In addition, because the fuel property detection sensor 21 does not come into contact with the fuel, the durability of the fuel property determination device 20 itself, including the fuel property detection sensor 21, is increased. Furthermore, the fuel property determination device 20 monitors the contamination rate of different oil types and stores the trends in the contamination rate. Therefore, the fuel property determination device 20 can retroactively determine the timing when the different oil type was unloaded into the storage tank 90 based on the timing when the contamination rate increased.

[0070] The fuel property determining device 20 determines the type of fuel from the reception intensity of the received terahertz wave signal, and determines whether water is mixed in the fuel from the fluctuation width of the received signal.

[0071] At this time, the terahertz waves are attenuated by the fuel passing through the fuel supply path 3. The amount of attenuation of the terahertz waves varies depending on the type of fuel oil. Therefore, the fuel property determining device 20 can determine the type of fuel by comparing the reception strength of the terahertz wave reception signal with data previously stored according to the type of oil. Furthermore, if water is mixed into the fuel, the fluctuation range of the reception signal increases depending on the water content of the fuel. Therefore, the fuel property determining device 20 can determine whether water is mixed into the fuel based on the fluctuation range of the reception signal of the terahertz waves. In addition, since the presence or absence of water in the fuel is determined based on the fluctuation range of the reception signal, the accuracy of the determination of the fuel property can be improved.

[0072] If the fluctuation width of the received terahertz wave signal is smaller than a predetermined value (second predetermined value V2), the fuel property determining device 20 compares the received signal with a signal corresponding to a preset fuel type, and determines the type of fuel.

[0073] When water is not mixed in the fuel, the fluctuation width of the received terahertz wave signal is smaller than a predetermined value (second predetermined value V2). Therefore, the fuel property determining device 20 can determine the type of fuel by comparing the reception strength of the received terahertz wave signal with data corresponding to the oil type in advance. Furthermore, since the type of fuel can be determined based on the received terahertz wave signal, the accuracy of the type determination can be improved.

[0074] If the fuel property determination device 20 determines that water has been mixed into the fuel or that the fuel type is different from that stored in the memory 27 (storage unit), the control valve 9 stops the fuel supply. Therefore, when water has been mixed into the fuel or the fuel is different from a preset oil type, the fuel supply can be stopped.

[0075] In the above embodiment, the memory 27 of the fuel property detection processing device 26 constitutes the storage unit, and the type of fuel previously set in the fuel supply path 3 is stored in the memory 27, but the present invention is not limited to this. For example, the memory (not shown) of the refueling control device 16 may constitute the storage unit, and the type of fuel previously set in the fuel supply path 3 may be stored in the memory of the refueling control device 16. In this case, when the fuel property determination device 20 is driven by the refueling control device 16, the type of fuel is input from the memory of the refueling control device 16 to the fuel property detection processing device 26.

[0076] In the above embodiment, the fuel property determination device 20 is applied to a fuel dispenser 1 (fuel supply device) connected to a predetermined storage tank 90, but the present invention is not limited to this. The fuel property determination device may also be applied to a portable fuel dispenser that can be connected to any storage tank or tank truck as a fuel supply device. Also, the fuel property determination device may be provided at the fuel outlet of the tank truck, and the fuel property determination device may determine the properties of the fuel when unloading it from the tank truck into the storage tank.

[0077] In addition, in S5 of the flowchart in FIG. 4, the fuel property detection processing device 26 determines whether the fuel is a different oil type or whether water is mixed in (normal) based on the difference ΔV between the received signal level of the terahertz waves that have passed through the fuel and the standard value. The present invention is not limited to this, and it is also possible to determine whether the fuel is different based on the difference ΔV from the standard value. As an example, consider a case where gasoline is set as the fuel. As shown in FIG. 3, in the case of gasoline that has not been mixed with water, the received signal level reaches a peak value at point B. In contrast, in the case of diesel fuel that has not been mixed with water, the received signal level reaches a peak value at point A, which is, for example, +4 dBV higher than the peak value at point B. Therefore, when the difference ΔV between the received signal level of the terahertz waves that have passed through the fuel and the standard value reaches a positive value, it is possible to determine that the set fuel and the fuel being discharged from the nozzle are different.

[0078] Furthermore, the fuel property detection processing device 26 converts the received terahertz wave signal into a voltage signal corresponding to the received terahertz wave intensity, and measures the water content based on the voltage signal. This simplifies the system compared to, for example, a case where a spectrophotometer is used to separate light into wavelengths and measure transmittance.

[0079] The specific numerical values ​​described in the above embodiment are merely examples, and the present invention is not limited to these exemplary values.

[0080] Next, as the fuel property determining device and the fuel supply device included in the above embodiment, for example, the following aspects are conceivable.

[0081] A fuel property determination device according to a first aspect is provided in a fuel supply path into which fuel flows, irradiates terahertz waves onto the fuel in the fuel supply path, and determines the presence or absence of water contamination in the fuel and the type of fuel from a received terahertz wave signal received through the fuel.

[0082] In the second aspect, in the first aspect, the type of fuel is determined from the reception intensity of the received terahertz wave signal, and whether or not water is mixed in the fuel is determined from the fluctuation width of the received signal.

[0083] As a third aspect, in the first aspect, when the fluctuation width of the received terahertz wave signal is smaller than a predetermined value, the received signal is compared with a signal corresponding to a preset type of fuel to determine the type of fuel.

[0084] In a fourth aspect, there is provided a fuel supply system including a fuel supply path through which fuel flows, a control means for stopping the fuel supply, and a memory unit in which a type of fuel previously set for the fuel supply path is stored. The fuel supply path is provided with a fuel property determination device that irradiates terahertz waves onto the fuel in the fuel supply path and determines the presence or absence of water in the fuel and the type of fuel from a received terahertz wave signal received through the fuel. When the fuel property determination device determines that water is present in the fuel or that the type of fuel is different from that stored in the memory unit, the control means stops the fuel supply. [Explanation of symbols]

[0085] 1. Fuel tank (fuel supply device) 2. Fuel tank housing (fuel supply device housing) 3 Fuel supply line (fuel supply path) 4. Pump 7 Flow meter 9 Control valve (control means) 10 Fuel supply hose (liquid supply hose) 11 Fuel supply nozzle (liquid supply nozzle) 12 Nozzle hanger 13 Nozzle switch 14 Display 15 Alarm 16 Fuel supply control device (fluid supply control unit) 20 Fuel property determination device 21 Fuel property detection sensor 22 Terahertz wave transmitter 23,25 Separation plate 24 Terahertz wave receiving unit 26 Fuel property detection and processing device 27 Memory (storage section)

Claims

1. A fuel property determination device is provided in a fuel supply path into which fuel flows, irradiates terahertz waves onto the fuel in the fuel supply path, and determines the presence or absence of water contamination in the fuel and the type of fuel from the received terahertz wave signal received through the fuel.

2. 2. The fuel property determining device according to claim 1, A fuel property determination device that determines the type of fuel from the reception strength of a received terahertz wave signal and determines whether water is mixed in the fuel from the fluctuation range of the received signal.

3. 2. The fuel property determining device according to claim 1, When the fluctuation width of a received terahertz wave signal is smaller than a predetermined value, the fuel property determining device compares the received signal with a signal corresponding to a preset fuel type to determine the type of fuel.

4. a fuel supply path through which fuel flows; a control means for stopping the fuel supply; a storage unit that stores a type of fuel that is set in advance in the fuel supply path, a fuel property determining device is provided in the fuel supply path, the fuel property determining device irradiates terahertz waves onto fuel in the fuel supply path, and determines the presence or absence of water in the fuel and the type of fuel from a received terahertz wave signal received through the fuel, a fuel supply device characterized in that, when the fuel property determination device determines that water has been mixed in the fuel or that the type of fuel is different from that stored in the memory unit, the control means stops the fuel supply.

Images