JP2007046916A - Fuel gas detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly detect fuel gas based on a sensor output. <P>SOLUTION: The hydrogen sensor output is acquired from time to time (S10), to check the presence of fluctuation in a value thereof (S12). When fluctuated, an inclination of a concentration output is found based on the concentration output during a fluctuated period (S14), to calculate a reach prediction concentration and a reach prediction time corresponding the inclination (S16). A degree of consistency between the concentration output at the time point when the reach prediction time lapses and the reach prediction concentration is evaluated at the time point (S18), so as to discriminate the determination of hydrogen leakage detection (S20) from the determination of abnormality in the hydrogen sensor output (S22). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel gas detection technique using a sensor, and more particularly to a technique for processing a concentration output of a sensor.

  In an apparatus using a fuel gas such as hydrogen gas, gas concentration detection and gas leak detection using a sensor are generally performed. The following patent documents 1 to 3 can be cited as documents related to such technology.

  The technique described in Patent Document 1 below detects a sensor abnormality based on the number of times when the concentration detected by the sensor exceeds a predetermined value, the duration, the accumulated time, and the like. This technique is used, for example, in an exhaust system on the oxygen electrode side of a fuel cell, and aims to reliably determine a decrease in sensitivity or an increase in sensitivity of the sensor.

  In Patent Document 2 below, a sensor is provided in the fuel gas piping path, the inclination angle of the concentration increase curve immediately after the fuel gas on-off valve is opened is calculated, and the estimated concentration is obtained based on information stored in advance. Technology is disclosed. This technique aims to control the fuel gas injection amount using the estimated concentration.

  Patent Document 3 listed below describes a technique for predicting the gas concentration based on an output value acquired at a predetermined time before the output of the gas sensor is stabilized. This technique has been made in order to keep the hydrogen gas concentration in the air off-gas discharged from the cathode of the fuel cell below an allowable value.

JP 2004-93203 A Japanese Utility Model Publication No. 5-73252 JP 2003-294676 A

  In general, it is desirable that the detection of fuel gas be performed quickly. In particular, when the detection is performed at a place where the gas amount should not be originally detected, the case where the detection is performed at a place where a certain amount of gas originally exists as in Patent Documents 1 to 3 above. On the other hand, it is desirable to focus on quickness rather than certainty to ensure safety.

  On the other hand, it can be said that it is actually not preferable that erroneous detection frequently occurs in the detection of fuel gas. In general, an abnormality caused by sensor characteristics or disturbance may occur in the sensor output of fuel gas. For example, in the case of a vehicle-mounted sensor, the output is not stable due to various disturbances such as temperature, humidity, vibration, air flow, and the reliability is lowered. However, in the past, it was possible to quickly detect abnormalities in sensor power supply and signal line disconnection short circuit, etc., but there was no technology to quickly detect various abnormalities such as abnormal noise, characteristic failure, bias abnormality, etc. It was an obstacle to gas detection. Particularly in a fuel cell vehicle or the like, the occurrence of fuel gas leakage is an extremely serious symptom, and prompt and reliable detection is required.

  An object of the present invention is to establish a new technique for quickly detecting fuel gas.

  Another object of the present invention is to speed up the detection of erroneous detection in a fuel gas detection device.

  Still another object of the present invention is to realize a fuel gas detection technique suitable for processing concentration output from a sensor installed at a place where fuel gas should not be detected.

  The fuel gas detection device according to the present invention performs estimation on a concentration output after a certain time based on an acquisition means for acquiring a concentration output of a sensor that asymptotically follows the fuel gas concentration and a concentration output in a tracking transient period. An estimation unit, and an evaluation unit that evaluates the validity of the estimation result by the estimation unit based on the concentration output after that time.

  The sensor detects one or more types of combustible gas and outputs the concentration thereof. The sensor may be incorporated in the fuel gas detection device and form a part thereof. What is the fuel detection device? It may be configured separately. The type of sensor is not particularly limited, and for example, a semiconductor sensor, a surface potential sensor, a gas heat conduction sensor, or the like can be used. The concentration output by the sensor generally follows asymptotically the surrounding fuel gas concentration to be measured. Tracking asymptotically means that a true value is not output in a short time (for example, 0.1 second) such as a normal sampling time interval, but gradually approaches a true value (approaching in an oscillatory manner such as overshooting). In other words, it means a change mode in which a true value is output after a certain long time (for example, about several seconds) elapses.

  The acquisition unit acquires the density output of the sensor. For example, the acquisition may be performed by directly inputting a voltage signal or a current signal output from the sensor in accordance with the concentration, or such a signal is input indirectly via an A / D converter or the like. It may be done.

  The estimation means estimates the density output after a certain time based on the acquired density output in the follow-up transition period. The tracking transition period is a period in which the concentration output changes to follow the new gas concentration. Based on the concentration output in the tracking transition period, the concentration output at one or more points in this period Based on instantaneous value, time change rate, or both (instantaneous value and time change rate). The time change rate may be calculated from instantaneous values at two or more time points. Moreover, it is desirable that after a certain time is within a time that can be estimated with a certain degree of accuracy. Specifically, the near future until the beginning of the following transitional period due to the next unknown fluctuation factor, such as the second half of the following transitional period or the period from the end of the following transitional period to the start of another following transitional period An example of setting is given. The estimation relating to the density output refers to estimation of the value of the density output itself, or estimation of an amount or event related to the density output. Specifically, examples of estimating fuel gas leakage and estimating failure of fuel gas piping and the like can be given. In the estimation, generally, it is necessary to make an appropriate assumption such as a constant concentration assumption or a constant concentration increase rate assumption with respect to the temporal change in the surrounding fuel gas concentration. Therefore, when the actual fluctuation differs from the assumption, such as the surrounding fuel gas concentration fluctuating every moment, it is necessary to be careful because an estimation error due to the difference occurs. Note that the estimation means can perform estimation a plurality of times based on the density output at different times (which may partially overlap) in the follow-up transition period.

  The evaluation means evaluates the estimation result by the estimation means based on the concentration output at the time required for estimation. Evaluation of the validity of the estimation result by the estimation means means making a judgment as to whether or how much the estimation result is valid. Specifically, examples include determining whether the estimation result is correct or not, and quantifying the accuracy of the estimation result. Such an evaluation can be carried out by performing a comparison operation or an evaluation operation using evaluation reference data or an evaluation operation expression that is created and stored in advance based on theory or experiment.

  According to this configuration, estimation is performed on the density output of the sensor after a certain time based on the density output in the tracking transition period, and the estimation result is evaluated based on the density output after that time. Therefore, it is possible to estimate the density output faster than the sensor follows the density, and the estimation result is quickly evaluated based on the actual density output. Moreover, the evaluation of this prediction is performed based on the concentration output at the tracking transition period and at different times (time periods) after the lapse of time. In other words, the double check is performed from different viewpoints based on the density output at two different times (time periods), and the reliability is improved as compared with the case based on only one density output.

  The estimation result or the evaluation result can be output to a built-in or external display device, or can be processed into secondary information by a built-in or external calculation device. Also, if the estimation result is worthy of attention, increase the sampling interval of this sensor or another sensor in the fuel gas detection device, or increase the sampling interval in another fuel gas detection device. It is also effective to enhance the detection capability for fuel gas.

  In one aspect of the fuel gas detection device of the present invention, there is provided determination means for determining that the concentration output of the sensor is abnormal when the evaluation means evaluates that the estimation result is not valid. Various processing can be performed when abnormality in density output is detected. For example, when an abnormality is detected, a warning output that alerts the display device or the like immediately may be output, or the use of this sensor may be stopped immediately. Of course, if the relevance is slightly bad, it is possible to operate as usual for the time being and to determine the processing mode when an abnormality is detected next time. In this aspect, it is possible to detect an abnormality in the sensor concentration output very quickly, and at the same time, it is quickly determined that there is no abnormality in the sensor concentration output. Therefore, quick output with reliable density output, secondary processing operation, and the like are possible.

  One aspect of the fuel gas detection device of the present invention includes an estimation result output means for outputting an estimation result when the estimation means evaluates that the estimation result is valid. In other words, when the reliability of the evaluation means was confirmed and the reliability could be confirmed, the output was promptly performed.

  One aspect of the fuel gas detection device of the present invention includes an estimation result output means for outputting an estimation result when the estimation means estimates. Thereby, the estimation result as the first report is output earlier than the sensor follows the density. However, since the estimation result has not yet been evaluated at this point, it is preferable to add information indicating that the estimation result is an estimate rather than an actual measurement.

  In one aspect of the fuel gas detection device of the present invention, a correction output unit is provided that performs an output for correcting the estimation result when the estimation unit evaluates that the estimation result is not valid. The correction of the estimation result can be performed, for example, by outputting information indicating that the estimation result is incorrect or by outputting information on the actual fuel gas concentration and correcting the estimation result. In this way, when the estimation result is not valid, the information based on the fact is promptly transmitted, thereby preventing the processing based on the erroneous estimation result from proceeding. When the estimation result is evaluated to be valid, information indicating that the estimation result is correct can be output.

  In one aspect of the fuel gas detection device of the present invention, the time after the estimation is performed by the estimation means is when the concentration output of the sensor completes following the actual fuel gas concentration. The estimation relating to the output is an estimation relating to the actual fuel gas concentration obtained when the follow-up is completed. Completion of follow-up refers to a point in time when the concentration of the fuel gas to be measured is accurately reflected in the concentration output. However, due to errors due to measurement and judgment, it is actually impossible to uniquely determine the time when tracking is completed.Here, the period with a width corresponding to the error is defined as the time when tracking is completed. expressing. A specific determination as to whether or not the follow-up has been completed can be made, for example, when the concentration output value is stable under the assumption that the gas concentration has not changed. In this aspect, the estimation result regarding the actual fuel gas concentration can be obtained earlier than the sensor actually follows the concentration.

  In one aspect of the fuel gas detection device of the present invention, there is provided an output means for performing an output related to the actual fuel gas concentration at the time of completion of tracking when the estimation means evaluates that the estimation result is appropriate. As a result, it is possible to quickly output the result of confirming the reliability.

  In one aspect of the fuel gas detection device of the present invention, the estimation regarding the concentration output by the estimation means is an estimation of the value of the fuel gas concentration. In this case, for example, the evaluation unit compares the estimated fuel gas concentration with the concentration output at the completion of the follow-up to evaluate the validity of the estimation result of the fuel gas concentration. If the evaluation result is appropriate, it can be said that the value of the fuel gas concentration is a reliable value consistent with the concentration output in both the follow-up transition period and the follow-up completion. The fuel gas concentration may be output as it is, or secondary processing such as determination of fuel gas leakage may be performed by comparison with a threshold value.

  In one aspect of the fuel gas detection device of the present invention, the estimation regarding the concentration output by the estimation means is an estimation of occurrence of fuel gas leakage. In this case, the evaluation unit evaluates the validity of the estimation result of the occurrence of the fuel gas leak based on, for example, the concentration output at the completion of the follow-up. The estimation or actual detection of the fuel gas leakage can be typically performed by comparing the concentration output with a reference value stored in advance. As a result, the fuel gas concentration detection device also functions as a gas leak detector.

  In one aspect of the fuel gas detection device of the present invention, a calculation means for calculating time change information of the concentration output in the follow-up transition period is provided, and the estimation means performs estimation based on the time change information calculated by the calculation means. In this case, information on the magnitude of the density output in the follow-up transition period can be used together. Information on the time change amount is calculated based on data at two or more points in the follow-up transition period. The calculation using the initial value of the following transition period is preferable because the subsequent processing of the density estimation means and the like can be performed quickly, but it should be noted that there is a possibility that the error in density estimation may increase. In addition, when the calculation is based on information at multiple points in the follow-up transition period, it is generally possible to estimate the concentration with high accuracy, but it should be noted that the amount of calculation increases.

  The estimation by the estimation means is expected to be more accurate when time change information is used than when only density output at individual time points is used. This is because, for example, when the density output includes a bias (offset), the density output value itself includes an error, but the time change amount does not include an error. Note that the estimation means can perform estimation based on the time change information calculated by the calculation means, for example, by comparing with correspondence information stored in advance. The correspondence information is information for associating the time change information and the actual fuel gas concentration, and can be implemented as, for example, a lookup table or a function.

  In one aspect of the fuel gas detection device of the present invention, the time change information calculated by the calculation means includes information on a second-order or third-order or higher-order time change amount. Then, the estimation means estimates the fuel gas concentration in consideration of the second-order or third-order or higher-order time variation. The estimation may be performed using correspondence information prepared for each value of the higher-order time change amount, or may be performed by correcting standard correspondence information with these higher-order time change amounts. In general, it is considered that the density output of the sensor does not follow the true value linearly but follows asymptotically asymptotically. Therefore, it is expected that the concentration can be accurately estimated in consideration of the second or higher order time change amount, rather than evaluating only the first order time change amount.

  In one aspect of the fuel gas detection device of the present invention, it is provided with a follow-up time predicting means for predicting the follow-up time until the follow-up of the concentration output is completed based on the time change information calculated by the calculating means. Therefore, for example, when the estimation unit performs estimation regarding the density output at the time of completion of tracking, the evaluation unit can perform evaluation by regarding the elapsed time of the tracking time predicted by the tracking time prediction unit as the time of tracking completion. Become. In general, the time until the sensor can be regarded as following varies depending on the fuel gas concentration. For example, when the concentration is high, the time change in the tracking transition period is large, and the time until the tracking is completed is long. When the concentration is low, the time change in the tracking transition period is small, and the time until the tracking is completed is short. Therefore, such a relationship is obtained theoretically or experimentally and stored as a formula or a table, and the required time until completion of tracking is predicted based on time change information. This makes it possible to perform gas leak confirmation and abnormality detection promptly and at an appropriate time.

  In one aspect of the fuel gas detection device of the present invention, the fuel gas detection device includes environmental information acquisition means for acquiring at least one of ambient temperature information, ambient humidity information, and ambient wind speed information, and the estimation means includes the environment information acquisition means. The actual fuel gas concentration is estimated in consideration of at least one of the acquired ambient temperature information, ambient humidity information, and ambient wind speed information. For example, in a situation where the surrounding environment can change greatly, such as in a fuel cell vehicle, it may be important to perform estimation in consideration of external factors that affect the estimation result. In the case of adopting this aspect, for example, the reference data and estimation calculation formula used for estimation may be obtained by expanding when external factors change.

  In one aspect of the fuel gas detection device of the present invention, the fuel gas is hydrogen gas. The fuel cell system of the present invention includes a fuel cell using fuel gas as fuel and the fuel gas detection device, and the sensor is arranged at a position where the fuel gas can be detected. The gas leak detectable position is, for example, a place where fuel gas should not normally be detected, such as outside the fuel gas piping or inside or outside the fuel cell (of course, a very small amount during normal operation due to various factors). It is possible that the fuel gas is detected), but when the fuel gas leaks, it indicates a place where the gas flows or accumulates.

  Hereinafter, as a typical embodiment of the present invention, an aspect of detecting hydrogen gas as fuel gas in a fuel cell vehicle will be described.

  FIG. 1 is a diagram showing a schematic configuration of a fuel cell vehicle 10 according to the present embodiment. Here, the configuration generally provided in the vehicle is omitted, and the configuration related to the fuel gas is mainly illustrated. The fuel cell vehicle 10 includes a hydrogen tank 12 filled with hydrogen gas, a hydrogen gas transport path 14 through which hydrogen gas is sent out from the hydrogen tank 12, and hydrogen supply from the hydrogen gas transport path 14 as main components for driving the vehicle. And a motor 18 driven by electric power generated in the fuel cell stack 16.

  Three hydrogen sensors 20, 22, and 24 are attached above the periphery of the hydrogen tank 12, the hydrogen gas transport path 14, and the fuel cell stack 16 in which hydrogen gas is handled. The fuel gas detection device 30 is a device realized by using the computer function of the electric control unit of the fuel cell vehicle 10, and receives an electric signal regarding the hydrogen concentration output from these hydrogen sensors 20, 22, 24. Detect hydrogen gas leakage. In addition to this, the fuel gas detection device 30 acquires a measurement signal about the environment in which the fuel cell vehicle 10 is placed, such as a temperature signal input from the temperature sensor 50, and uses it as a determination condition for hydrogen gas leakage. . When the fuel gas detection device 30 detects a hydrogen gas leak, this is displayed on the display unit 60. The display unit 60 is attached to the panel of the driver's seat of the fuel cell vehicle 10, and the driver can visually recognize hydrogen gas leakage. Note that the fuel cell vehicle 10 can be programmed to take a corresponding operation process such as stopping the vehicle as necessary when hydrogen gas leakage is detected.

  In general, the hydrogen sensors 20, 22, and 24 cannot immediately follow the concentration of hydrogen gas, and a slight time lag occurs in the concentration output. The fuel gas detection device 30 uses the characteristics of the hydrogen sensors 20, 22, and 24 to detect hydrogen gas leakage quickly and reliably. The fuel gas detection device 30 is realized by controlling hardware having a calculation function and a storage function by a program, and includes a control unit 32, a fluctuation detection unit 34, an inclination calculation unit 36, and a concentration estimation unit as main functional components. 38, a correspondence table 40 and an evaluation unit 42 are provided.

  The control unit 32 controls the operation of each component and data input / output. The fluctuation detection unit 34 monitors the signals from the hydrogen sensors 20, 22, and 24 from moment to moment to detect whether the detected concentration has changed. The inclination calculation unit 36 calculates an initial time change amount of the detected concentration of the hydrogen sensor when a change is detected. Further, the concentration estimation unit 38 estimates an actual hydrogen gas concentration based on the calculated amount of change in time, and estimates an estimated arrival time required until the actual hydrogen gas concentration is output. In this estimation, the correspondence table 40 created and stored in advance based on an experiment is referred to. In the correspondence table 40, the actual hydrogen gas concentration and the estimated arrival time with respect to the initial time change amount are recorded.

  When the estimated arrival time has elapsed, the evaluation unit 42 determines whether or not the difference between the hydrogen gas concentration reached by the hydrogen sensors 20, 22, and 24 at that time and the previously estimated hydrogen gas concentration are within the set error. To determine. If they match, it is determined that the concentration output of the hydrogen sensor is reliable, and it is determined that a gas leak corresponding to the concentration has definitely occurred. The occurrence of hydrogen gas leak is displayed on the display unit 60. On the other hand, if the two do not match, it is determined that there is an abnormality in the concentration output of the hydrogen sensor.

  Next, an example of the operation of the fuel gas detection device 30 will be specifically described with reference to FIGS.

  FIG. 2 is a flowchart showing a processing operation process in the fuel gas detection device 30. In the fuel gas detection device 30, when the concentration output from the hydrogen sensor is received (S10), the fluctuation detection unit 34 compares it with one or more immediately preceding values to detect whether or not the output has fluctuated (S12). . If there is no change, repeat this process until there is a change. On the other hand, if there is a change, the slope calculation unit 36 calculates the slope of the change over time based on the output of the hydrogen sensor at two or three time points (S14). Then, the concentration estimation unit 38 compares the obtained inclination with the data stored in the correspondence table 40, and the expected concentration that is the concentration output that is reached when the hydrogen sensor reflects the actual hydrogen gas concentration, An expected arrival time, which is a time for completing the follow-up to the actual hydrogen gas concentration, is calculated (S16).

  When the expected arrival time elapses, the evaluation unit 42 compares the concentration output of the hydrogen sensor at that time with the predicted arrival concentration, and evaluates whether or not they match within the set error range (S18). If they match, it is determined that the occurrence of hydrogen leakage has been detected definitely (S20), and if they do not match, it is determined that there is an abnormality in the hydrogen sensor output (S22). Thereby, it becomes possible to appropriately separate hydrogen gas leakage from erroneous detection. The determination result is promptly displayed on the display unit 60 shown in FIG. Further, according to programming, the control unit 32 takes countermeasures such as disconnecting the sensor output when the sensor output is abnormal, or closing the hydrogen tank 12 and stopping the vehicle when a gas leak is detected. .

  FIG. 3 is a graph schematically showing the sensor output 70 after the time when the output of the hydrogen sensor fluctuates. The horizontal axis is time, and the vertical axis is concentration. The circles denoted by reference numerals 72 to 76 represent output values at the respective sampling points for processing the sensor output. Reference numeral 72 indicates a storage when the value of the sensor output 70 that has been constant until then starts to increase. The sensor output 70 increases rapidly before and after this point, gradually increases, and gradually approaches a value balanced with the surrounding hydrogen gas concentration. Here, the calculated slope 80 is obtained based on the three density outputs in the early transition period indicated by reference numerals 72 to 76.

  FIG. 4 is a diagram for explaining data stored in the correspondence table 40 of the fuel gas detection device 30. In this figure, the horizontal axis represents time and the vertical axis represents concentration, two sensor output curves obtained experimentally are drawn. One is a high-concentration sensor output 90 obtained when there is a high-concentration hydrogen gas leak, and the other is a low-concentration sensor output 92 obtained when there is a low-concentration hydrogen gas leak. is there.

  Similar to the curve shown in FIG. 3, both sensor outputs 90 and 92 draw a curve that gradually decreases the rate of increase and follows the hydrogen gas concentration. The high-density follow-up time 94 indicates a time in which the follow-up can be regarded as being completed in the high-concentration sensor output 90, and the low-concentration follow-up time 96 represents a follow-up completion time in the low-concentration sensor output 92. The high concentration follow-up time 94 is longer (slower) than the low concentration follow-up time 96, indicating that the higher the concentration, the longer the follow-up time. During this time, the sensor output 90 at the time of high concentration has reached the reached concentration 97 at the time of high concentration, and the sensor output 92 at the time of low concentration has reached the reached concentration 98 at the time of low concentration. The reached density 97 at the high density is higher than the reached density 98 at the low density, and naturally, the higher the density, the higher the reached density. Further, these reached concentrations 97 and 98 are higher than the leakage determination threshold 100, and both are concentrations that should be determined as hydrogen gas leakage.

  Such a difference between the sensor output 90 at the high concentration and the sensor output 92 at the low concentration when the tracking is completed can be predicted by examining the magnitude of the slope in the tracking transient period. In other words, the high concentration sensor output 90 has a large slope at the beginning of the follow-up transition period as indicated by reference numeral 102, and the low concentration sensor output 92 has an initial slope at the beginning of the follow-up transition period as indicated by reference numeral 104. The inclination is small. Therefore, if the relationship between the various slopes in the initial period of the tracking transition period and the concentration when the tracking is completed and the concentration reached at that time is examined in advance, the presence or absence of gas leakage can be determined based on the initial output of the hydrogen sensor. Such data is stored in the correspondence table 40 shown in FIG. 1, and prediction based on this data is performed in step S16 shown in FIG.

  The embodiment described above can be variously modified.

  For example, a mode in which the determination of the output abnormality of the hydrogen sensor performed after the expected arrival time in the flowchart shown in FIG. 2 is performed at a faster time is conceivable. That is, if the predicted value in the latter period of the tracking transition period is compared with the actual concentration, the abnormality of the sensor output can be determined at that time. In this case, when it is determined that there is no abnormality in the sensor output, it is confirmed that the predicted concentration reached is reliable. Therefore, it is possible to output the gas leak determination result based on the prediction quickly and with sufficient reliability.

  Further, for example, the calculation of the estimation of the arrival density and the expected arrival time performed based on the inclination may be repeatedly performed based on the density output data at a new time point. In general, the more reliable the estimation is based on new data, the higher the reliability of the estimation. Therefore, it is effective to perform an inclination calculation based on new data one after another and to perform an estimation calculation based on the inclination.

  Furthermore, it is also effective to use a second-order or higher-order time change amount for estimation. For example, it is considered that the sensor output curve shown in FIG. 4 can be approximated by an exponential function that saturates toward a certain value if a simple first-order differential equation model is adopted. Therefore, if the parameters (time constant and asymptotic value) of the theoretical exponential function curve are determined by fitting, it will be possible to accurately determine the temporal change of the sensor output.

It is a figure which shows the structural example of the fuel gas detection apparatus mounted in the fuel cell vehicle. It is a flowchart which shows the flow of the process in a fuel gas detection apparatus. It is a schematic diagram which shows the example of calculation of the inclination in a follow-up transition period. It is a schematic diagram which shows the characteristic of each sensor output of a high density | concentration and a low density | concentration.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell vehicle, 12 Hydrogen tank, 14 Hydrogen gas transport path, 16 Fuel cell stack, 18 Motor, 20, 22, 24 Hydrogen sensor, 30 Fuel gas detection apparatus, 32 Control part, 34 Fluctuation detection part, 36 Inclination calculation part , 38 Concentration estimation unit, 40 Correspondence table, 42 Evaluation unit, 50 Temperature sensor, 60 Display unit, 70 Sensor output, 80 Calculated slope, 90 High concentration sensor output, 92 Low concentration sensor output, 94 High concentration Follow-up time, 96 Follow-up time at low density, 97 Achievable density at high density, 98 Achieved density at low density, 100 Leakage determination threshold.

Claims (15)

Acquisition means for acquiring the concentration output of the sensor that asymptotically follows the fuel gas concentration;
Based on the concentration output in the follow-up transition period, an estimation means for estimating the concentration output after a certain time,
Evaluation means for evaluating the validity of the estimation result by the estimation means based on the concentration output after that time,
A fuel gas detection device comprising: The fuel gas detection device according to claim 1,
A fuel gas detection device comprising: determination means for determining that there is an abnormality in the concentration output of the sensor when the evaluation means evaluates that the estimation result is not valid. The fuel gas detection device according to claim 1 or 2,
A fuel gas detection device comprising: estimation result output means for outputting an estimation result when the evaluation result is evaluated to be valid by the evaluation means. The fuel gas detection device according to claim 1,
A fuel gas detection device comprising: estimation result output means for outputting an estimation result at a time point when estimation is performed by the estimation means. The fuel gas detection device according to claim 4, wherein
A fuel gas detection device comprising: a correction output means for outputting an output for correcting the estimation result when the evaluation means evaluates that the estimation result is not valid. The fuel gas detection device according to claim 1,
A certain time after the estimation means makes an estimate is when the concentration output of the sensor completes following the actual fuel gas concentration,
The fuel gas detection apparatus according to claim 1, wherein the estimation relating to the concentration output made by the estimation means is an estimation relating to an actual fuel gas concentration obtained when the follow-up is completed. The fuel gas detection device according to claim 6, wherein
A fuel gas detection device comprising: output means for outputting an actual fuel gas concentration at the time of completion of follow-up when the estimation means evaluates that the estimation result is valid. The fuel gas detection device according to claim 1,
The fuel gas detection device characterized in that the estimation of the concentration output by the estimation means is an estimation of a value of the fuel gas concentration. The fuel gas detection device according to claim 1,
The fuel gas detection device characterized in that the estimation of the concentration output by the estimation means is an estimation of occurrence of fuel gas leakage. The fuel gas detection device according to claim 1,
A calculation means for calculating time change information of the density output in the tracking transition period is provided.
A fuel gas detection apparatus characterized in that the estimation means performs estimation based on the time change information calculated by the calculation means. The fuel gas detection device according to claim 10,
The time change information calculated by the calculation means includes information on a second-order or third-order or higher-order time change amount. The fuel gas detection device according to claim 10,
A fuel gas detection device comprising: a follow-up time predicting means for predicting a follow-up time until the follow-up of the concentration output is completed based on the time change information calculated by the calculating means. The fuel gas detection device according to claim 1,
Environmental information acquisition means for acquiring at least one of ambient temperature information, ambient humidity information, ambient wind speed information,
The estimation unit performs estimation regarding a density output after a certain time in consideration of at least one of ambient temperature information, ambient humidity information, and ambient wind speed information acquired by the environment information acquisition unit. A fuel gas detection device. The fuel gas detection device according to any one of claims 1 to 13,
A fuel gas detection device, wherein the fuel gas is hydrogen gas. A fuel cell using fuel gas as fuel,
The fuel gas detection device according to any one of claims 1 to 14,
With
A fuel cell system, wherein the sensor is disposed at a position where fuel gas leakage can be detected.

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