JP2011180105A - Device for suppot of setting average period, fuel residue detection system, and average period setting support method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for support of setting an average period, along with a fuel residue detection system and average period setting support method, capable of easily and properly determining the average period used for measurement of liquid level. <P>SOLUTION: The average period setting support device 50 cyclically measures the liquid level of fuel, calculates the average value of the liquid level measured in a preset average period, and detects the residue of the fuel based on the average value. At this point, the average period setting support device acquires the cyclically measured liquid level for a predetermined analysis period, determines the amplitude value at each of a plurality of frequencies included in the fluctuation waveform of the liquid level, extracts amplitude values exceeding a predetermined reference value from the amplitude values at the plurality of frequencies, calculates the cycle of the lowest frequency of the frequencies corresponding to the extracted amplitude values, and outputs the calculated cycle as an average period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention periodically measures the liquid level of the fuel remaining in the fuel tank of the vehicle, calculates an average value of the liquid level measured during a preset average period, and calculates the average An average period setting support device that supports setting of an average period for measuring the liquid level height when detecting the remaining amount of the fuel in the fuel tank based on a value, such an average period setting support device And a mean period setting support method used in such an average period setting support apparatus.

  2. Description of the Related Art Conventionally, a fuel remaining amount detecting device mounted on a vehicle has a liquid level detecting unit that detects a liquid level (that is, a liquid level) of fuel in a fuel tank. The liquid level detecting means has a contact that slides on the resistor in accordance with the position of the float that floats on the fuel surface, and outputs a voltage obtained by dividing the voltage applied to both ends of the resistor to the contact. Such a configuration is generally adopted. The fuel remaining amount detecting device detects the remaining amount of fuel based on the electrical characteristics of the liquid level detecting means, that is, the voltage output from the contact point, and displays the detected remaining fuel amount. The fuel gauge provided on the instrument panel is controlled.

  In such a fuel remaining amount detecting device, since the liquid level in the fuel tank of the vehicle fluctuates when the vehicle tilts or vibrates, the float follows the liquid level fluctuation in the fuel tank and floats. As a result, the display of the fuel gauge may have an error. Therefore, in the conventional fuel remaining amount detection device, the average value of the liquid level detected during a preset average period (also referred to as a simple average value or an arithmetic average value) is used for detecting the remaining amount of fuel. The measurement error due to the fluctuation of the liquid level was reduced. However, for example, if the setting of the average period is short, the influence of the fluctuation of the liquid level cannot be sufficiently removed, the accuracy of the remaining amount of fuel becomes low, and if the setting of the average period is long, the remaining amount There has been a problem that the amount detection is delayed and the update timing of the remaining amount display is delayed.

  In order to solve such a problem, in the fuel remaining amount detection device proposed in Patent Document 1, by changing the above-mentioned average period according to the vehicle state, for example, during traveling with a large liquid level fluctuation, etc. Lengthens the average period to prevent a decrease in the accuracy of the remaining fuel level, or shortens the average period during refueling with a small liquid level fluctuation or immediately before starting the engine to prevent a delay in displaying the remaining amount. It was out.

  Further, in the remaining fuel amount detection device proposed in Patent Document 2, the simple average value for each block compiled for each predetermined number (that is, for each predetermined average period) of the remaining fuel amount data taken in every predetermined cycle. Then, a weighted average value obtained by further averaging these simple average values is calculated and used for detection of the remaining amount of fuel, so that the averaging process is performed twice to reduce the accuracy of the remaining fuel amount. It was preventing. Further, by using the weighted average number of times (parameter) calculated based on the distribution of the latest block data, fuel remaining amount data with a time width appropriately adjusted according to the fluctuation state of the liquid level is obtained. As the target, the weighted average is calculated to detect the remaining amount of fuel. That is, when the liquid level fluctuates in an unstable manner, the number of times increases and the time period is relatively long (that is, the average period). If the remaining amount of fuel is detected based on the remaining fuel amount data or if the liquid level is stable, the number of times is reduced and the remaining fuel amount in a relatively short time width (that is, the average period) is reduced. The remaining amount of fuel is detected based on the quantity data to prevent a decrease in the accuracy of the remaining amount of fuel and a delay in displaying the remaining amount.

JP-A-57-10416 Japanese Patent Laid-Open No. 9-287997

  However, a thin fuel tank may be mounted horizontally in a vehicle or the like that needs to improve the efficiency of the space in the vehicle against the backdrop of a demand for an increase in passenger compartment space. Since the change in the remaining amount of fuel with respect to the change in the liquid level is very large, the detected value of the remaining amount of fuel will change greatly even if the liquid level is slightly changed. In order to set an appropriate value that balances the accuracy of the remaining amount of fuel and the delay in displaying the remaining amount for each average time, it takes a lot of man-hours, such as the need to repeat many experiments. For this reason, there is a problem that the setting of the average period is very difficult.

  The present invention aims to solve the above problems. That is, the present invention provides an average time setting support device, a fuel remaining amount detection system, and an average time setting support method that can easily obtain an appropriate average time for the average time used for measuring the liquid level. The purpose is to do.

  In order to achieve the above object, the invention described in claim 1 periodically measures the level of fuel remaining in the fuel tank of the vehicle as shown in the basic configuration diagram of FIG. In calculating an average value of the liquid level height measured in a preset average period and detecting the remaining amount of the fuel in the fuel tank based on the average value, the level of the liquid level is calculated. An average period setting support device 50 that supports setting of an average period used for measurement, and (a) a liquid level height acquisition unit 51a that acquires the liquid level height measured periodically over a predetermined analysis period; (B) spectrum analysis means 51b for obtaining amplitude values for the plurality of frequencies for a plurality of frequencies included in the fluctuation waveform of the liquid level obtained by the liquid level height obtaining means; By the spectrum analysis means An amplitude value exceeding a predetermined reference value is extracted from the amplitude values obtained for each of the plurality of frequencies, and a cycle calculating means 51c for calculating a cycle of the lowest frequency among the frequencies corresponding to the extracted amplitude values. And (d) an average period output support unit 51d that outputs the period calculated by the period calculation unit as the average period.

  In the invention described in claim 2, in the invention described in claim 1, the liquid level height acquired by the liquid level height acquisition means 51a as shown in the basic configuration diagram of FIG. The liquid level height obtained by provisional averaging means 51e for calculating an average value for each temporary average period shorter than the analysis period, and obtained by the spectrum analysis means 51b by the liquid level height obtaining means 51a. Instead of the above, for the plurality of frequencies included in the fluctuation waveform of the average value of the liquid level calculated by the temporary averaging means 51e, it is means for obtaining the amplitude value for each frequency. It is.

  In order to achieve the above object, the invention described in claim 3 periodically measures the liquid level height of the fuel remaining in the fuel tank of the vehicle, and measures the level measured in a preset average period. An average value of the liquid level height is calculated, and based on this average value, a remaining fuel amount detecting device for detecting the remaining amount of the fuel in the fuel tank, and an average period of time used for measuring the liquid level height A fuel remaining amount detection system having an average period setting support apparatus for supporting setting, wherein the average period setting support apparatus includes the average period setting support apparatus according to claim 1 or 2 as the average period setting support apparatus. This is a remaining fuel amount detection system.

  In order to achieve the above-mentioned object, the invention described in claim 4 periodically measures the liquid level of the fuel remaining in the fuel tank of the vehicle, and measures the level measured in a preset average period. In calculating an average value of the liquid level height and detecting the remaining amount of the fuel in the fuel tank based on the average value, a liquid level height acquisition means, a spectrum analysis means, a period calculation means, An average period setting support method for supporting setting of an average period used for measurement of the liquid level using a computer provided with an average period output means, wherein (a) the liquid level height acquisition means The liquid level acquisition step of acquiring the liquid level height measured periodically over a predetermined analysis period, and (b) the liquid level height acquisition step acquired by the spectrum analysis means For fluctuation waveform of liquid level A spectrum analysis step for obtaining an amplitude value for each of the plurality of frequencies, and (c) a predetermined value from among the amplitude values for the plurality of frequencies obtained in the spectrum analysis step by the period calculation means. A period calculation step of extracting an amplitude value exceeding the reference value of the first and calculating a cycle of the lowest frequency among the frequencies corresponding to the extracted amplitude value; and (d) in the cycle calculation step by the average period output means. An average period setting support method that sequentially includes an average period output step of outputting the calculated period as the average period.

  According to the first and fourth aspects of the present invention, the liquid level height measured periodically is acquired over a predetermined analysis period, and a plurality of frequencies included in the fluctuation waveform of the liquid level height are obtained. The amplitude value for each of the plurality of frequencies is obtained, the amplitude value exceeding a predetermined reference value is extracted from the amplitude values for the plurality of frequencies, and the lowest frequency among the frequencies corresponding to the extracted amplitude values And the calculated period is output as an average period. The frequency corresponding to the amplitude value exceeding the predetermined reference value has the most influence on the fluctuation range (that is, variation in value) of the original fluctuation waveform including the predetermined reference value. By setting the period of the lowest frequency among the frequencies corresponding to amplitude values exceeding the average period as the average period, the average value is obtained, so that the frequency included in the fluctuation waveform and higher frequencies (that is, other than the reference value) The amplitude of the fluctuation waveform is small, and the fluctuation width of the fluctuation waveform can be efficiently reduced without making the average period longer than necessary. Accordingly, the fluctuation range of the fluctuation waveform can be efficiently reduced, that is, an appropriate average period in which the accuracy of the remaining amount of fuel and the delay of the remaining amount display are adjusted in a balanced manner can be easily obtained.

  According to the invention described in claim 2, for the liquid level obtained over a predetermined analysis period, an average value for each temporary average period shorter than the analysis period is calculated, and instead of the liquid level height. Then, the amplitude value for each of the plurality of frequencies is obtained for the plurality of frequencies included in the calculated fluctuation waveform of the average value. The liquid level of the fuel tank fluctuates due to, for example, road irregularities or centrifugal force on a curve, but the fluctuation of the liquid level due to these factors is relatively gradual. The frequency components included in are many low frequency components, while there are few high frequency components. That is, among the frequencies included in the fluctuation waveform, the low frequency has a large amplitude value, and the high frequency has a small amplitude value. Then, by using a fluctuation waveform that has been averaged in advance in the provisional average period, the amplitude value at a frequency having a period of the provisional average period and a higher frequency is reduced, and the influence on the fluctuation waveform is further reduced. Therefore, it is possible to accurately detect the frequency that most affects the fluctuation range of the fluctuation waveform.

  According to the invention described in claim 3, since the average period setting support device described in claim 1 or 2 outputs the average period used for measuring the liquid level in the fuel remaining amount detection device, The fluctuation range of the fluctuation waveform can be efficiently reduced, that is, an appropriate average period in which the accuracy of the remaining amount of fuel and the delay of the remaining amount display are adjusted in a balanced manner can be easily obtained.

It is a figure which shows the basic composition of the average period setting assistance apparatus of this invention. It is a block diagram which shows one Embodiment of the fuel residual amount detection system of this invention. It is a front view of the combination meter by which the fuel meter with which the vehicle meter of the fuel residual amount detection system of FIG. 2 is equipped is arrange | positioned. FIG. 2 is a configuration diagram of a personal computer of the fuel remaining amount detection system. It is a flowchart which shows an example of the average period setting assistance process which concerns on this invention which CPU with which the personal computer of FIG. 4 is provided performs. It is a graph which shows an example of the waveform of the liquid level height (A / D value) which the personal computer of FIG. 4 acquired. It is a graph which shows an example of the waveform of the average value (A / D value) of the liquid level height calculated for every temporary average period about the waveform of FIG. It is a graph which shows an example of the waveform obtained by performing a Fourier-transform process about the fluctuation waveform of the average value of the liquid level height of FIG. It is a graph which shows the waveform which expanded the range of A1 in FIG. 7 is a graph illustrating an example of a waveform of an average value (A / D value) of liquid level height calculated for each average period obtained by the personal computer of FIG. 4 with respect to the waveform of FIG. It is a graph which shows an example of the waveform obtained by performing a Fourier-transform process about the fluctuation waveform of the average value of the liquid level height of FIG. It is a graph which shows the waveform which expanded the range of A2 in FIG. It is a graph which shows the detection result of fuel residual amount when the average period of the vehicle instrument of FIG. 2 is made into the conventional value. FIG. 5 is a graph showing the detection result of the remaining amount of fuel when the average period of the vehicle instrument of FIG. 2 is a value obtained by the personal computer of FIG. 4. It is a graph which shows an example of the waveform obtained by performing a Fourier-transform process about the fluctuation | variation waveform of the liquid level height of FIG.

  Hereinafter, an embodiment of a remaining fuel detection system according to the present invention will be described with reference to FIGS.

  A thin fuel tank 5 is mounted flat on a vehicle (not shown) provided with the fuel remaining amount detection system 1 shown in FIG. Further, a fuel sender unit 40 as a liquid level detecting means is installed in the fuel tank 5.

  The fuel sender unit 40 includes a winding resistor VR and a float (not shown) that floats on the liquid level L of the fuel F in the fuel tank 5. The winding resistor VR includes a winding-like resistor, and is provided with three terminals: one end of the resistor, the other end, and a contact that slides on the resistor. The one end is connected to a vehicle instrument 10 described later, and the other end and the contact are connected to the ground GND. The contact is connected to the float and moves on the resistor according to the liquid level. Therefore, the resistance value of the winding resistor VR changes according to the remaining amount of the fuel F remaining in the fuel tank 5, that is, the liquid level.

  As shown in FIG. 2, the fuel remaining amount detection system 1 includes a vehicle instrument 10 as a fuel remaining amount detection device and a personal computer (hereinafter referred to as a personal computer) 50 as an average period setting support device.

  The vehicle instrument 10 includes a fuel gauge 20, a control unit 30, and fixed resistors R1 and R2.

  The fuel gauge 20 is a well-known pointer-type instrument, and as shown in FIG. 3, is provided in a combination meter 3 or the like disposed on an instrument panel of a vehicle (not shown). The fuel gauge 20 is disposed on the back side of the dial 22 provided with a plurality of indicators 21 such as letters and scales indicating the remaining amount of fuel, and based on a control signal from the control unit 30 described later. A rotating inner unit (not shown) that rotates the pointer shaft, and a pointer member 23 that is fixed to the distal end of the pointer shaft of the rotating inner unit and that is rotatably disposed along the front surface of the dial 22. I have.

  The plurality of indicators 21 are arranged in an arc along the outer edge of the dial 22. The rotating internal unit is a well-known stepping motor that rotates a pointer shaft in accordance with a pulse signal (such as the number of pulses) input as a control signal. The rotating inner unit is connected to the control unit 30, receives the pulse signal corresponding to the remaining amount of fuel sent from the control unit 30, and moves the pointer member 23 fixed to the tip of the pointer shaft. It is rotated along an index 21 provided on the dial 22. Then, when these indicators 21 are instructed by the pointer member 23, the remaining amount of fuel is displayed in cooperation with the pointer member 23. The fuel gauge 20 may be constituted by a liquid crystal display device or the like that displays a numerical value indicating the remaining amount of fuel.

  The control unit 30 is configured by a known microcomputer (MPU) or the like. As is well known, the MPU is a central processing unit (CPU) that performs various processes and controls according to a predetermined program, a ROM that is a read-only memory storing programs and various parameters for the CPU, and various data. RAM, which is a readable / writable memory having an area necessary for CPU processing operations, and can retain various stored data even when the power supply is cut off. An EEPROM having various storage areas necessary for the storage is provided.

  In addition, the control unit 30 includes an A / D (Analog / Digital) conversion circuit that converts an analog voltage into digital data, a CAN communication control unit for connecting to a CAN (Controller Area Network) that is an in-vehicle network, and the like. Has an external interface. In this A / D conversion circuit, a voltage obtained by dividing the power supply voltage VCC supplied from a battery or the like by the fixed resistor R1 and the winding resistor VR of the fuel sender unit 40 is the output voltage of the fuel sender unit 40 ( That is, the liquid level is input via the fixed resistor R2. The A / D conversion circuit can input an A / D value obtained by converting the input output voltage (analog voltage) of the fuel sender unit 40 into digital data (that is, the input voltage value can be input to the A / D conversion circuit). A relative value representing a voltage range equally divided by a predetermined resolution is output to the CPU. The CAN communication control unit is connected to a CAN bus laid in the vehicle.

  In the ROM, the CPU calculates the average value of the liquid level measured during a preset average period, measuring means for periodically measuring the liquid level of the fuel remaining in the fuel tank of the vehicle. Averaging means, fuel remaining amount detecting means for detecting the remaining amount of the fuel in the fuel tank based on the average value, and periodically measuring the liquid level height is output to the CAN bus through the CAN communication control unit. Programs that function as various means such as a liquid level output means are stored in advance. The CPU functions as these means and the like by executing various programs stored in the ROM. The ROM also stores in advance a fuel remaining amount conversion table for detecting the remaining amount of fuel based on the A / D value of the fuel sender unit 40 output by the A / D conversion circuit. The average period used for measuring the liquid level is set in the EEPROM. Alternatively, the average period may be set in the ROM.

  The control unit 30 (i.e., the CPU) periodically (e.g., the liquid level height of the fuel remaining in the fuel tank of the vehicle) of the fuel sender unit 40 output by the A / D conversion circuit (e.g. , Every 0.1 seconds), an average value of the A / D values measured in an average period preset in the EEPROM is calculated, and the fuel in the fuel tank is calculated based on the average value. Detect the remaining amount of. Further, the control unit 30 outputs information indicating the A / D value measured periodically through the CAN communication control unit on the CAN bus.

  As shown in FIG. 4, the personal computer 50 has a CPU (Central Processing Unit) 51 that controls the overall operation of the personal computer 50 in accordance with a predetermined program. The CPU 51 has a ROM 52 which is a read-only memory storing a program for the CPU 51 and the like via the bus B, and a read / write freely having a work area for storing various programs and various data necessary for processing work of the CPU 51. A RAM 53 is connected.

  A storage device 54 is connected to the CPU 51 via the bus B, and a hard disk device, a large-capacity memory, or the like is used as the storage device 54. The storage device 54 stores an average period setting support program for obtaining an average period used for measuring the liquid level. The average period setting support program stored in the storage device 54 is read from the storage device 54, stored (loaded) in the RAM 53, and executed by the CPU 51. The CPU 51 functions as various means such as a liquid level height acquisition means, a spectrum analysis means, a period calculation means, an average period output means, and a temporary averaging means by executing the average period setting support program.

An input device 55, a display device 56, and an external I / F unit 57 are connected to the CPU 51 via the bus B. The input device 55 includes a keyboard, a mouse, and the like, and outputs input information corresponding to a user operation to the CPU 51. As the display device 56, various display devices such as a known liquid crystal display and CRT are used. The display device 56 displays various information such as an average period obtained by executing the above-described average period setting support program, for example, under the control of the CPU 51.

  The external I / F unit 57 includes various interfaces such as well-known USB and CAN, and is a part for connecting an external device or the like including these interfaces. In the present embodiment, the external I / F unit 57 is a CAN of the external I / F unit 57. The interface is connected to a CAN bus laid in the vehicle.

  Next, an example of the operation (average period setting support process) according to the present invention performed by the CPU 51 of the personal computer 50 provided in the remaining fuel amount detection system 1 will be described with reference to the flowchart of FIG.

  When an operation for starting the average period setting support process is input to the input device 55 of the personal computer 50, the average period setting support program stored in the storage device 54 of the personal computer 50 is loaded onto the RAM 53, and the average period setting is performed by the CPU 51. A support program is executed. Then, after a predetermined initialization process is executed, the process proceeds to step S110.

  In step S110, the liquid level height periodically measured by the vehicle instrument 10 described above is acquired over a predetermined analysis period. Specifically, information indicating the A / D value (that is, the liquid level height) of the fuel sender unit 40 output on the CAN bus by the vehicle instrument 10 through the CAN interface of the external I / F unit 57 is stored in advance. Acquired over a defined analysis period (eg, 1024 seconds). The acquired information is sequentially stored as a liquid level height in a liquid level storage area provided on the RAM 53. And after the said analysis period passes, it progresses to step S120.

  In step S120, an average value for each temporary average period shorter than the analysis period is calculated for the liquid level obtained in step S110. Specifically, the liquid level height for each temporary average period (for example, 25.6 seconds (= analysis period 1024 seconds ÷ 40)) is sequentially read out from the liquid level storage area, and the liquid level in these temporary average periods is read. The average value of the surface height (arithmetic average value) is calculated. For example, if the provisional average period is 25.6 seconds, the analysis period of 1024 seconds is (1) 0 to 25.5 seconds, (2) 25.6 seconds to 51.1 seconds, (40) 998. Dividing into 40 sections of .4 seconds to 1023.9 seconds, and calculating the average value of the liquid level for each section. Then, the calculated average value is sequentially stored in an average value storage area provided on the RAM 53. And after calculating an average value about all the temporary average periods, it progresses to step S130.

  In step S130, amplitude values for the plurality of frequencies are obtained for a plurality of frequencies included in the fluctuation waveform of the average value calculated in step S120. Specifically, by sequentially reading average values from the average value storage area and performing a well-known Fourier transform process on these average values, a plurality of frequencies included in the fluctuation waveform of the average value and the amplitude value of each frequency. And are calculated. Then, the calculated plurality of frequencies and the respective amplitude values are stored in association with each other in an amplitude storage area provided on the RAM 53. Then, the process proceeds to step S140.

  In step S140, an amplitude value exceeding a predetermined reference value is extracted from the amplitude values for a plurality of frequencies included in the fluctuation waveform of the average value calculated in step S130, and the lowest frequency among the frequencies corresponding to the extracted amplitude value is extracted. The frequency cycle is calculated. Specifically, amplitude values are sequentially read out from the amplitude storage area, and amplitude values exceeding a predetermined reference value (in the present embodiment, amplitude value 6) are extracted. Then, the frequency stored in association with the extracted amplitude value is read, and the reciprocal of the lowest frequency among the read frequencies is calculated as a period at the frequency. Alternatively, as an amplitude value extraction method, in addition to the above, for example, the amplitude values are sequentially read out from the amplitude storage area, and the amplitude values from the top to the fifth (that is, the sixth amplitude value from the top are determined as predetermined values). As long as an amplitude value (frequency) that greatly affects the fluctuation waveform of the average value can be obtained, such as extraction (as a reference value), the method is arbitrary. Then, the process proceeds to step S150.

  In step S150, the period calculated in step S140 is output as an average period. Specifically, using the period calculated in step S140 as an average period, a control signal for displaying (that is, outputting) the average period is generated and transmitted to the display device 56. And the process of this flowchart is complete | finished.

  Step S110 described above corresponds to the liquid level acquisition means in the claims, step S120 corresponds to the temporary averaging means in the claims, and step S130 corresponds to the spectrum analysis means in the claims. Step S140 corresponds to the period calculation means in the claims, and step S150 corresponds to the average period output means in the claims. Moreover, step S110 mentioned above is corresponded to the liquid level height acquisition process in a claim, step S120 is corresponded to a temporary averaging process, step S130 is equivalent to the spectrum analysis process in a claim, step S140 corresponds to the period calculation step in the claims, and step S150 corresponds to the average period output step in the claims.

  Next, the operation (action) according to the present invention in the fuel remaining amount detection system 1 described above will be described with reference to FIGS.

  The fuel tank 5 is previously filled with an amount of fuel (for example, 26.1 L) in which the fluctuation range of the liquid level is the largest. When the vehicle is turned on, the control unit 30 of the vehicle meter 10 of the fuel remaining amount detection system 1 performs A / D of the fuel sender unit 40 indicating the level of the fuel F remaining in the fuel tank 5. Values are measured periodically (eg, every 0.1 second). Then, for each average period (for example, 25.6 seconds) set in the EEPROM (or ROM) in advance, an average value of the A / D values measured in the average period is calculated. Then, the remaining value of the fuel is detected by comparing the calculated average value of the A / D values with a fuel remaining amount conversion table stored in the ROM. And the control part 30 transmits the control signal according to this detected fuel residual value to the fuel gauge 20, and the fuel gauge 20 instruct | indicates this detected fuel residual value. Moreover, the control part 30 of the vehicle instrument 10 outputs the A / D value of the fuel sender unit 40 measured periodically on a CAN bus.

  The personal computer 50 starts the average period setting support process by the operation of the operator after the vehicle is turned on. The personal computer 50 (that is, the CPU 51) uses the A / D value of the fuel sender unit 40 output on the CAN bus by the control unit 30 of the vehicle instrument 10 as a liquid level height for a predetermined analysis period (for example, 1024 seconds). (S110). In FIG. 6, an example of the waveform of the liquid level height (A / D value) which the personal computer 50 acquired is shown.

  And the personal computer 50 calculates the average value for every predetermined temporary average period (for example, 25.6 seconds) about the acquired liquid level height (S120). FIG. 7 shows an example of the waveform of the average liquid level height (A / D value) calculated for each temporary average period with the temporary average period of 25.6 seconds for the waveform of FIG.

  And the personal computer 50 calculates | requires the amplitude value for every said some frequency about the some frequency contained in the fluctuation waveform of the average value of a liquid level (S130). FIG. 8 shows an example of a waveform obtained by performing Fourier transform processing on the fluctuation waveform of the average value of the liquid level in FIG.

  And the personal computer 50 extracted the amplitude value exceeding predetermined reference value (namely, amplitude value 6) out of the amplitude value for every frequency contained in the fluctuation waveform of the average value of liquid level, and extracted The cycle of the lowest frequency among the frequencies corresponding to the amplitude value is calculated. FIG. 9 shows a waveform obtained by enlarging the range of A1 in FIG. For example, in FIG. 9, the portion surrounded by the circle W is the amplitude of the lowest frequency, and the frequency at this time is 0.005 Hz, so the cycle is 200 seconds. Also, the line K1 in FIG. 9 corresponds to a frequency of 0.039 Hz with a period of the temporary average period of 25.6 seconds, and the frequency on the right side of the line K1 is a frequency higher than the frequency of 0.039 Hz. The frequency on the left side of the line K1 is a frequency lower than the frequency 0.039 Hz. The amplitude of the frequency on the right side of the line K1 is extremely smaller than the amplitude of the frequency on the left side of the line K1, and the effect of temporary averaging appears.

  Then, the personal computer 50 displays the calculated cycle on the display device 56 as an average period. And the average period calculated | required in this way is fed back to the production process of the vehicle instrument 10, and is set to EEPROM (or ROM) of the control part 30 of the vehicle instrument 10 newly produced. Then, the vehicle instrument 10 performs the averaging process at a period of 200 seconds, thereby reducing the amplitude value of a high frequency of 0.005 Hz or more (that is, the averaging process functions as a low-pass filter to attenuate the amplitude). ) In other words, since it is not necessary to perform an averaging process that reduces the amplitude value of the frequency of 0.005 Hz or less, the average period is not set longer than necessary.

  FIG. 10 shows an example of the waveform of the average value (A / D value) of the liquid level height calculated for each average period, with the average period of the waveform shown in FIG. Indicates. FIG. 11 shows an example of a waveform obtained by performing a Fourier transform process on the fluctuation waveform of the average value of the liquid level in FIG. FIG. 12 shows a waveform obtained by enlarging the range A2 in FIG. The K2 line in FIG. 12 corresponds to a frequency of 0.005 Hz with an average period of 200 seconds as a cycle. The frequency on the right side of the K2 line is a frequency higher than the frequency of 0.005 Hz, and is on the left side of the K2 line. The frequency is a frequency lower than 0.005 Hz.

  In FIG. 12, the portion surrounded by the circle V is the frequency at which the maximum amplitude value is obtained. This frequency is 0 Hz, that is, it does not affect the fluctuation width of the fluctuation waveform of the average value of the liquid surface height. Is. For this reason, the portion surrounded by the circle U having the next largest amplitude value is the frequency that most affects the fluctuation width of the fluctuation waveform. The amplitude value at this frequency is enclosed by the circle W in the graph of FIG. Compared with the amplitude value of the broken part, it becomes very small. Therefore, by using the average period obtained by the personal computer 50 as described above, the fluctuation range of the fluctuation waveform can be efficiently reduced, that is, the accuracy of the remaining amount of fuel and the delay of the remaining amount display can be adjusted in a balanced manner.

  Moreover, the present inventors conducted the test for confirming the effect of this invention.

  The fuel tank 5 is formed in a substantially flat rectangular parallelepiped shape, but is provided with complex irregularities according to the shape of the vehicle space in which it is installed. For this reason, the liquid level height of the fuel F remaining in the fuel tank 5 and the remaining fuel amount are linearly related (proportional) as long as they are limited to a certain section. The fluctuation range of the liquid level varies depending on the remaining amount. The inventors set the average period of the vehicle instrument 10 described above at the conventional value (25.6 seconds) and the remaining amount of fuel at which the fluctuation range of the liquid level height is the largest in the personal computer 50 described above. In each case where the obtained value (200 seconds) is used, the fuel is injected into the fuel tank 5 so as to have a plurality of different fuel remaining amounts, and the fuel tank 5 is given a swing close to the actual running state. A test to detect the remaining amount of fuel was conducted. The results are shown in FIGS. In each figure, an average value (AVR) of the detected remaining fuel amount and a value (AVR ± 3σ) obtained by adding and subtracting three times the standard deviation σ to the average value are shown. That is, for each remaining amount of fuel, a range including almost all of the detected values (99% or more) is shown.

  FIG. 13 shows the detection result of the remaining amount of fuel when the average period of the vehicle instrument 10 is a conventional value, and FIG. 14 shows the case where the average period of the vehicle instrument 10 is a value obtained by the personal computer 50. The fuel remaining amount detection result is shown. According to these figures, in FIG. 13, the detection value ranges for adjacent fuel remaining amounts overlap (D1 to D4), so there is a risk of erroneous detection of the remaining fuel amount, whereas in FIG. It can be seen that detection value ranges for adjacent fuel remaining amounts do not overlap, so that erroneous detection of the remaining fuel amount can be avoided.

  As described above, according to the present invention, the liquid level height that is periodically measured is acquired over a predetermined analysis period, and a plurality of frequencies included in the fluctuation waveform of the liquid level height are obtained for each of the plurality of frequencies. An amplitude value exceeding a predetermined reference value is extracted from the amplitude values for each of the plurality of frequencies, and a cycle of the lowest frequency among the frequencies corresponding to the extracted amplitude value is calculated. The calculated cycle is output as an average period. The frequency corresponding to the amplitude value exceeding the predetermined reference value has the most influence on the fluctuation range (that is, variation in value) of the original fluctuation waveform including the predetermined reference value. By setting the period of the lowest frequency among the frequencies corresponding to amplitude values exceeding the average period as the average period, the average value is obtained, so that the frequency included in the fluctuation waveform and higher frequencies (that is, other than the reference value) The amplitude of the fluctuation waveform is small, and the fluctuation width of the fluctuation waveform can be efficiently reduced without making the average period longer than necessary. Accordingly, the fluctuation range of the fluctuation waveform can be efficiently reduced, that is, an appropriate average period in which the accuracy of the remaining amount of fuel and the delay of the remaining amount display are adjusted in a balanced manner can be easily obtained.

  Further, for the liquid level obtained over a predetermined analysis period, an average value for each provisional average period shorter than the analysis period is calculated, and instead of the liquid level height, a fluctuation waveform of the calculated average value is used. An amplitude value for each of the plurality of frequencies is obtained for a plurality of frequencies included. The liquid level of the fuel tank fluctuates due to, for example, road irregularities or centrifugal force on a curve, but the fluctuation of the liquid level due to these factors is relatively gradual. Among the frequency components contained in the, there are many low frequency components, while there are few high frequency components. That is, among the frequencies included in the fluctuation waveform, the low frequency has a large amplitude value, and the high frequency has a small amplitude value. Then, by using a fluctuation waveform that has been averaged in advance in the provisional average period, the amplitude value at a frequency having a period of the provisional average period and a higher frequency is reduced, and the influence on the fluctuation waveform is further reduced. Therefore, it is possible to accurately detect the frequency that most affects the fluctuation range of the fluctuation waveform.

  In the present embodiment described above, the amplitude value for each of the plurality of frequencies is obtained for a plurality of frequencies included in the fluctuation waveform of the average value of the liquid level, but is not limited thereto. For example, with respect to a fluctuation waveform of the liquid level, without obtaining an average value for each temporary average period, the fluctuation waveform is directly used, and the amplitude for each of the plurality of frequencies is included in the plurality of frequencies included in the fluctuation waveform. A value may be obtained. That is, in the flowchart of FIG. 5 described above, the process of step S120 may be omitted. FIG. 15 shows an example of a waveform obtained by performing Fourier transform on the fluctuation waveform of the liquid level in FIG.

  Moreover, in this embodiment, although the suitable average period was calculated | required using the personal computer 50, it is not limited to this, The above-mentioned average is carried out by CPU of the control part 30 with which the vehicle instrument 10 is provided. Period setting support processing (processing shown in the flowchart of FIG. 5) may be performed. For example, the vehicle instrument 10 calculates the average period when the operation state shifts to a maintenance mode or the like in which various parameters are set. Then, the calculated average period is updated by the EEPROM itself, or when the vehicle instrument 10 includes a liquid crystal display device, it is displayed on the device. In this case, the vehicle instrument 10 corresponds to an average period setting support device and a remaining fuel amount detection system.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1 Fuel Remaining Detection System 5 Fuel Tank 10 Vehicle Instrument (Fuel Remaining Detection Device)
20 Fuel meter 30 Control unit 40 Fuel sender unit 50 Personal computer (Average period setting support device)
51 CPU (Liquid surface height acquisition means, spectrum analysis means, period calculation means, average period output means, provisional averaging means)

Claims (4)

The liquid level height of the fuel remaining in the fuel tank of the vehicle is periodically measured, and an average value of the liquid level height measured in a preset average period is calculated, and based on this average value An average period setting support device for assisting in setting an average period used for measuring the liquid level in detecting the remaining amount of the fuel in the fuel tank,
(A) Liquid level height acquisition means for acquiring the liquid level height measured periodically over a predetermined analysis period;
(B) Spectrum analysis means for obtaining an amplitude value for each of the plurality of frequencies for a plurality of frequencies included in the fluctuation waveform of the liquid level obtained by the liquid level height obtaining means;
(C) An amplitude value exceeding a predetermined reference value is extracted from the amplitude values for each of the plurality of frequencies obtained by the spectrum analysis means, and a cycle of the lowest frequency among the frequencies corresponding to the extracted amplitude value A period calculating means for calculating
(D) average period output means for outputting the period calculated by the period calculation means as the average period;
An average period setting support device characterized by comprising: The liquid level obtained by the liquid level obtaining means has temporary averaging means for calculating an average value for each temporary average period shorter than the analysis period, and
The spectrum analyzing means includes a plurality of fluctuation waveforms of the average value of the liquid level calculated by the temporary averaging means instead of the liquid level acquired by the liquid level acquiring means. The average period setting support device according to claim 1, wherein the average period setting support device is a means for obtaining an amplitude value for each frequency. The liquid level height of the fuel remaining in the fuel tank of the vehicle is periodically measured, and an average value of the liquid level height measured in a preset average period is calculated, and based on this average value A fuel remaining amount detecting system comprising: a fuel remaining amount detecting device that detects a remaining amount of the fuel in the fuel tank; and an average period setting supporting device that supports setting of an average period used for measuring the liquid level. In
A fuel remaining amount detection system comprising the average period setting support device according to claim 1 or 2 as the average period setting support device. The liquid level height of the fuel remaining in the fuel tank of the vehicle is periodically measured, and an average value of the liquid level height measured in a preset average period is calculated, and based on this average value In detecting the remaining amount of the fuel in the fuel tank, the liquid level is obtained using a computer including a liquid level height obtaining unit, a spectrum analyzing unit, a period calculating unit, and an average period output unit. An average period setting support method for supporting setting of an average period used for height measurement,
(A) a liquid level acquisition step of acquiring the liquid level measured periodically by the liquid level acquisition unit over a predetermined analysis period;
(B) a spectrum analysis step of obtaining amplitude values for each of the plurality of frequencies for a plurality of frequencies included in the fluctuation waveform of the liquid level height acquired in the liquid level height acquisition step by the spectrum analysis unit; ,
(C) The period calculation means extracts an amplitude value exceeding a predetermined reference value from the amplitude values for each of the plurality of frequencies obtained in the spectrum analysis step, and among the frequencies corresponding to the extracted amplitude value A cycle calculating step for calculating the cycle of the lowest frequency;
(D) an average period output step of outputting the cycle calculated in the cycle calculation step as the average period by the average period output means;
The average period setting support method characterized by having sequentially.

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