Ignition delay time monitoring device, ignition delay time monitoring program, and ignition delay time monitoring method

Abstract

To provide an ignition delay time monitoring device capable of allowing a user to properly grasp malfunction of a combustion device.SOLUTION: An analysis portion 21B statistically analyzes an aggregate of ignition delay times of each of ignition trials of a prescribed number of times initially executed in a combustion device, and obtains statistic data of the aggregate as reference aggregate data. The analysis portion 21B statistically analyzes the aggregate of the ignition delay times of each of the ignition trials of the prescribed number of times recently performed, and obtains the statistic data of the aggregate as the latest statistic data. A comparison portion 21C compares the latest statistic data with reference statistic data and outputs a result of the comparison. According to this constitution, a user can grasp whether malfunction occurs in the combustion device or not with high accuracy, so that the malfunction of the combustion device can be properly grasped.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an ignition delay time monitoring device, an ignition delay time monitoring program, and an ignition delay time monitoring method for monitoring an ignition delay time from an ignition command to ignition detection in an ignition trial for igniting a burner. [Background technology]

[0002] In a combustion device or the like, an ignition trial is performed to ignite a burner. Patent Document 1 discloses a technique for measuring an ignition delay time from an ignition command to ignition detection in this ignition trial, and determining that the combustion device is malfunctioning when the measured ignition delay time falls outside a predetermined range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-60570 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although the technology described in Patent Document 1 is useful, for example, it is difficult for a user to properly grasp the tendency of a malfunction of the combustion device (such as the tendency of a malfunction to occur). In addition, with this technology, for example, even if the ignition delay time falls outside the predetermined range due to an unexpected event that is not caused by a malfunction, the combustion device is determined to be malfunctioning. As described above, it is difficult to say that the technology described in Patent Document 1 allows a user to properly grasp the malfunction of the combustion device.

[0005] An object of the present invention is to provide an ignition delay time monitoring device, an ignition delay time monitoring program, and an ignition delay time monitoring method that allow a user to appropriately grasp malfunctions in a combustion device. [Means for solving the problem]

[0006] In order to solve the above problems, an ignition delay time monitoring device according to a first aspect of the present invention includes a collection unit configured to collect ignition delay times from an ignition instruction to ignite a burner to ignition detection in an ignition trial, an analysis unit configured to statistically analyze a set of the ignition delay times for each of a predetermined number of ignition trials collected by the collection unit and obtain statistical data of the set as first statistical data, and a comparison unit configured to compare the first statistical data with second statistical data that is different from the first statistical data and serves as a reference and is prepared as statistical data of the set of ignition delay times when the ignition trial is performed the predetermined number of times, and to output a comparison result.

[0007] The analysis unit may be configured to statistically analyze a set of the ignition delay times for each of the predetermined number of initial ignition trials of the combustion device, collected by the collection unit, using the same method as used to obtain the first statistical data, and to obtain statistical data of the set as the second statistical data.

[0008] The first statistical data may include first distribution data indicating a distribution of the number of the ignition trials which resulted in the ignition delay time for each of the ignition delay times, and the second statistical data may include second distribution data indicating a distribution of the number of the ignition trials which resulted in the ignition delay time for each of the ignition delay times.

[0009] The comparison unit may be configured to compare the first statistical data with the second statistical data by graphing the first distribution data and the second distribution data in association with each other, with a first axis representing the ignition delay time and a second axis representing the number of ignition trials, and output each graph of the first distribution data and the second distribution data in association with each other as the comparison result.

[0010] The first statistical data and the second statistical data may include a statistical quantity representing a distribution of the ignition delay time, and the comparison unit may be configured to estimate the presence or absence of a malfunction of the combustion device and, if a malfunction occurs, the type of the malfunction by comparing the statistical quantity included in the first statistical data with the statistical quantity included in the second statistical data, and to output a result of the estimation as the comparison result.

[0011] The combustion apparatus may include an ignition device used to ignite the burner, and the statistical amount may include an average value of the ignition delay time, a mode of a distribution of the number of ignition trials that resulted in that ignition delay time for each of the ignition delay times, and a standard deviation of the distribution of the number of times, and the comparison unit may be configured to estimate that the type of malfunction is at least one of a disturbance in an air-fuel ratio, which is a ratio of air to fuel supplied to the burner, and a malfunction of a spark generating unit of the ignition device, when the average value is longer, the mode is smaller, and the standard deviation is larger in the first statistical data than in the second statistical data.

[0012] The combustion apparatus may include an ignition device used when igniting the burner, the statistical amount including a standard deviation of a distribution of the number of times of the ignition trials that reached the ignition delay time for each of the ignition delay times and a number of peaks in the distribution of the number of times, the number of peaks included in the reference statistical data being one, and the comparison unit may be configured to estimate that the type of malfunction is a malfunction of a spark generating unit of the ignition device when the standard deviation of the first statistical data is larger than that of the second statistical data and the number of peaks included in the first statistical data is multiple.

[0013] The combustion device may include a flame detector used for the ignition detection, and the statistical amount includes an average value of the ignition delay time, and the comparison unit may be configured to estimate, when the average value of the first statistical data is shorter than that of the second statistical data, that the type of malfunction is at least one of improper positioning of the flame detector, a malfunction of the flame detector, and an air-fuel ratio disturbance (gas rich).

[0014] An ignition delay time monitoring program according to a second aspect of the present invention causes a computer to execute a collection step configured to collect ignition delay times from an ignition instruction to ignite a burner to ignition detection in an ignition trial; an analysis step configured to statistically analyze a set of the ignition delay times for each of a predetermined number of ignition trials collected by the collection step and obtain statistical data of the set as first statistical data; and a comparison step configured to compare the first statistical data with second statistical data, which is different from the first statistical data and serves as a reference and is prepared as statistical data of the set of ignition delay times when the ignition trials are performed the predetermined number of times, and output a comparison result.

[0015] An ignition delay time monitoring method according to a third aspect of the present invention includes an analysis step of statistically analyzing a set of ignition delay times from an ignition command to an ignition detection in each of a predetermined number of ignition trials for igniting a burner and obtaining statistical data of the set as first statistical data, and a comparison step of comparing the first statistical data with second statistical data, which is different from the first statistical data and serves as a reference and is prepared as statistical data of the set of ignition delay times when the ignition trials are performed the predetermined number of times, and obtaining a comparison result. Effect of the Invention

[0016] According to the present invention, a user can appropriately recognize malfunctions in a combustion device. [Brief description of the drawings]

[0017] [Figure 1]FIG. 1 is a configuration diagram of a combustion system having an ignition delay time monitoring device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a timing chart of the combustion sequence executed in the combustion system. [Diagram 3] FIG. 3 is a hardware configuration diagram of the ignition delay time monitoring device. [Figure 4] FIG. 4 is a configuration diagram of an ignition delay time monitoring device. [Diagram 5] FIG. 5 is a diagram illustrating an example of the configuration of distribution data. [Figure 6] FIG. 6 is a graph of the distribution data of FIG. [Figure 7] FIG. 7 is a graph showing the bounce distribution data of the most recent statistical data and the reference distribution data of the reference statistical data. [Figure 8] FIG. 8 is a graph of the bounce distribution data of the most recent statistical data and the reference distribution data of the reference statistical data. [Figure 9] FIG. 9 is a graph of the bounce back distribution data of the most recent statistical data and the reference distribution data of the reference statistical data. [Figure 10] FIG. 10 is a diagram showing the process contents of the comparison unit according to the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention and its modified examples will be described with reference to the drawings.

[0019] (Embodiment) As shown in FIG. 1, an ignition delay time monitoring device 20 according to an embodiment of the present invention is used in a combustion system 10 and monitors an ignition delay time Td in the combustion system 10, which will be described later. The combustion system 10 includes a combustion device 30 that performs combustion, and a combustion control device 70 that controls the combustion device 30, in addition to the ignition delay time monitoring device 20. In this embodiment, the ignition delay time Td is monitored so that the user can properly understand the malfunction of the combustion device 30 by understanding the change in the ignition delay time Td. The "malfunction" refers to an abnormality in which the combustion device 30 is operable before the combustion device 30 becomes inoperable, that is, a minor abnormality. Hereinafter, the combustion device 30 and the combustion control device 70 will be described first, and then the ignition delay time monitoring device 20 will be described.

[0020] The combustion device 30 includes a combustion appliance 40, a fuel supply system 50, an air supply system 60, a control motor M, a high opening position sensor HS, and a low opening position sensor LS.

[0021] The combustion device 40 burns the fuel gas in the combustion chamber R. The combustion device 40 includes a combustion furnace 41 that forms the combustion chamber R, a main burner 42 that burns the fuel gas to heat the inside of the combustion chamber R, a pilot burner 43 that burns the fuel gas to ignite the main burner 42, and an ignition device (igniter) 44 that ignites the pilot burner 43. The pilot burner 43 ignited by the ignition device 44 is used to ignite the main burner 42. Therefore, the ignition device 44 can also be said to be a device used when igniting the main burner 42. The ignition device 44 includes a spark generating unit 44A such as a discharge electrode. The combustion device 40 further includes a flame detector 45 that detects the flame activity of the burners, more specifically, the main burner 42 and the pilot burner 43, and a temperature sensor 46 that detects the temperature in the combustion chamber R. The flame activity is a measure of how actively the flame is occurring, and in this case, it is the flame intensity.

[0022] The fuel supply system 50 supplies fuel gas from the outside to the combustion appliance 40. The fuel supply system 50 includes a fuel flow path 51 through which the fuel gas supplied to the combustion appliance 40 flows. The fuel flow path 51 includes a main flow path 51A through which the fuel gas is supplied from the outside, and a first flow path 51B and a second flow path 51C branched from the main flow path 51A. The first flow path 51B is connected to the main burner 42, and the second flow path 51C is connected to the pilot burner 43.

[0023] The fuel supply system 50 further includes a gas pressure switch 52 provided in the main flow path 51A, main valves 54A and 54B which are safety shutoff valves provided in the first flow path 51B, and pilot valves 54C and 54D which are safety shutoff valves provided in the second flow path 51C. The gas pressure switch 52 is turned ON when the pressure of the fuel gas supplied from the outside is equal to or higher than a predetermined pressure. The main valves 54A and 54B open and close the first flow path 51B. The pilot valves 54C and 54D open and close the second flow path 51C. The fuel supply system 50 also includes a damper 55 for adjusting the fuel flow rate provided in the main flow path 51A.

[0024] The air supply system 60 supplies air to the combustion appliance 40. The air supply system 60 includes an air flow path 61 through which air to be supplied to the combustion appliance 40 flows, and a blower 62 that supplies air to the air flow path 61. The air flow path 61 includes a main flow path 61A connected to the blower 62, and a first flow path 61B and a second flow path 61C branched from the main flow path 61A. The first flow path 61B is connected to the main burner 42. The second flow path 61C is connected to the pilot burner 43.

[0025] The air supply system 60 further includes an air pressure switch 63 that is provided in the main flow path 61A and turns on when the air pressure from the blower 62 is equal to or higher than a predetermined air pressure. The air supply system 60 further includes a damper 65 for adjusting the air flow rate that is provided in the main flow path 61A.

[0026] The dampers 55 and 65 for adjusting the fuel or air flow rate are driven by a control motor M in a linkage to control the opening of the fuel passage 51 and the air passage 61. Driven by the linkage, the opening of each of the dampers 55 and 65 is controlled so that the air-fuel ratio, which is the ratio of fuel to air supplied to the main burner 42, is maintained at a desired ratio (ideal ratio for combustion). The amount of fuel and air supplied to the main burner 42 is adjusted by the opening of each of the dampers 55 and 65, thereby adjusting the flame activity of each burner, and thereby controlling the heating temperature for heating the combustion chamber R.

[0027] The high opening position sensor HS detects when the dampers 55 and 65 reach a predetermined high opening position. The low opening position sensor LS detects when the dampers 55 and 65 reach a predetermined low opening position. Each of the sensors HS and LS turns ON when the dampers 55 and 65 reach the high opening position or the low opening position.

[0028] The combustion control device 70 is composed of various computers such as a PLC (Programmable Logic Controller) and a personal computer. The combustion control device 70 is also called a burner controller. The combustion control device 70 monitors the states (ON / OFF) of the gas pressure switch 52, the wind pressure switch 63, the high opening position sensor HS, and the low opening position sensor LS. Various signals are input to the combustion control device 70 from the flame detector 45, the temperature sensor 46, and the like. The combustion control device 70 controls the ignition device 44, the main valves 54A and 54B, the pilot valves 54C and 54D, the blower 62, and the dampers 55 and 65, and the like, based on the monitoring results and various signals.

[0029] The combustion control device 70 controls the operation of the combustion device 30 in accordance with a predetermined combustion sequence. This combustion sequence includes stages such as "start check," "pre-purge," "waiting for ignition," "pilot ignition," "pilot only," "main ignition," "main only" (also called "main stable"), and "steady combustion."

[0030] 2 shows a time chart of the combustion sequence from start-up of the combustion device 30 to steady combustion. When a start-up input is received from the outside (point t1 in chart A), the combustion control device 70 controls the blower 62 to start blowing air into the air flow path 61 (point t1 in chart B), and sends a drive command to the control motor M in the opening direction (point t1 in chart D). The drive command in the opening direction opens the dampers 55 and 65.

[0031] When the wind pressure caused by the air supply from the blower 62 reaches a predetermined wind pressure, the wind pressure switch 63 turns ON (point t2 in chart C). The period P1 from point t1 to point t2 is the "start check" time period.

[0032] When the air pressure switch 63 is turned ON and the high opening position sensor HS detects that the opening positions of the dampers 55 and 65 have reached the high opening position and turns ON (point t3 in Chart E), the combustion control device 70 starts timing the pre-purge time from this point on.

[0033] After the pre-purge time has elapsed, the combustion control device 70 sends a drive command to the control motor M in the closing direction (point t4 in chart D). This causes the dampers 55 and 65 to operate in the closing direction. The period P2 from point t3 to point t4 is the "pre-purge" time period.

[0034] When the low opening position sensor LS detects that the dampers 55 and 65 have reached the low opening position and turns ON (point t5 in chart F), the combustion control device 70 opens the pilot valves 54C and 54D after a predetermined waiting time has elapsed (point t6 in chart G) and activates the ignition device 44 (point t6 in chart H). The predetermined waiting time is, for example, the time from when the low opening position is detected until the supply of fuel gas starts and the gas pressure switch 52 turns ON. The period P3 from point t4 to point t6 is the "ignition waiting" time zone.

[0035] By opening the pilot valves 54C and 54D, fuel gas is supplied from the fuel supply system 50 to the pilot burner 43, and the pilot burner 43 ejects the fuel gas. In this state, when the ignition device 44 is operated, an ignition spark is generated from the spark generating unit 44A of the ignition device 44, and this ignition spark ignites the fuel ejected from the pilot burner 43. This ignites the pilot burner 43. In this embodiment, air required for combustion of the fuel gas is also supplied from the air supply system 60 to the pilot burner 43, and is ejected from the pilot burner 43. The fuel supply system 50 and the air supply system 60 are configured so that the air-fuel ratio of the fuel and air supplied to the pilot burner 43 becomes the desired ratio (ideal ratio for combustion) when the dampers 55 and 65 are in the low opening position as described above. The pilot burner 43 may be configured to be ignited by the surrounding air.

[0036] The ignition of the pilot burner 43 is detected by the flame detector 45. The flame detector 45 outputs a detection signal indicating the flame activity of the pilot burner 43 to the combustion control device 70. The combustion control device 70 detects the ignition of the pilot burner 43 when it determines that the flame activity indicated by the detection signal has exceeded a predetermined first threshold value. Here, as shown in Chart I, it is assumed that the pilot burner 43 is ignited at point t7 and this ignition is detected.

[0037] When the combustion control device 70 detects ignition of the pilot burner 43, it terminates the operation of the ignition device 44, i.e., the generation of the ignition spark (point t8 in chart H). The period P4 from point t6 to point t8 during which the ignition device 44 is operated is the "pilot ignition" time period. When the combustion control device 70 cannot detect ignition of the pilot burner 43 for a predetermined period of time, it aborts the combustion sequence as a time-out.

[0038] After detecting the ignition of the pilot burner 43 and terminating the operation of the ignition device 44, the combustion control device 70 waits for a predetermined period until point t9. This predetermined period, i.e., period P5 from point t8 to point t9, is the "pilot only" time period during which the pilot burner 43 is burned alone. In "pilot only", the combustion control device 70 monitors the flame activity of the pilot burner 43 based on the detection signal from the flame detector 45. When the flame activity falls below a predetermined intensity during the above-mentioned predetermined period, the combustion control device 70 determines that the pilot burner 43 has misfired and stops the combustion sequence.

[0039] After the above-mentioned predetermined period has elapsed, the combustion control device 70 opens the main valves 54A and 54B (point t9 in chart J). By opening the main valves 54A and 54B, the supply of fuel to the main burner 42 is started. Air is also supplied to the main burner 42 from the air supply system 60. The main burner 42 in a state in which air and fuel are supplied ejects fuel and air, and ignites using the flame of the pilot burner 43 as a pilot flame. The flame detector 45 outputs a detection signal indicating the sum of the flame activity of the main burner 42 and the pilot burner 43 to the combustion control device 70. When the combustion control device 70 determines that the sum of the flame activity indicated by the detection signal exceeds a predetermined second threshold value, it determines that the main burner 42 has ignited. Here, as shown in chart K, it is assumed that the main burner 42 is ignited at point t10, and this ignition is detected.

[0040] When the combustion control device 70 detects the ignition of the main burner 42, it closes the pilot valves 54C and 54D to terminate the combustion of the pilot burner 54 (see point t11 ​​in charts G and I). The period P6 from point t9 to point t11 ​​is the “main ignition” time period during which the main burner 42 is ignited.

[0041] After detecting the ignition of the main burner 42 and closing the pilot valves 54C and 54D, the combustion control device 70 waits for a predetermined period until point t12. This predetermined period, that is, the period P7 from point t11 ​​to point t12, is the "main only" time period during which the main burner 42 is burned alone. In the "main only" mode, the combustion control device 70 monitors the flame activity of the main burner 42 based on the detection signal from the flame detector 45. If the flame activity falls below a predetermined intensity during the predetermined period, the combustion control device 70 determines that the main burner 42 has misfired and stops the combustion sequence.

[0042] After waiting for the above-mentioned predetermined period, the combustion control device 70 starts feedback control of the control motor M so that the temperature in the combustion chamber R indicated by the detection signal supplied from the temperature sensor 46 becomes a target value, using the temperature as a feedback value (point t12 in chart D). The period from point t12 onwards is a "steady combustion" period in which the main burner 42 performs steady combustion. The specific method of feedback control in steady combustion is arbitrary, but for example, proportional control (P control), proportional-integral control (PI control), or proportional-integral-derivative control (PID control) is adopted. When the gas pressure switch 52 or the wind pressure switch 63 is turned OFF during steady combustion, the combustion control device 70 determines that an abnormality has occurred and stops steady combustion.

[0043] A sequence including at least each stage from "pilot ignition" to "main only" in the combustion sequence is also called an ignition trial. The combustion control device 70 measures the ignition delay time Td required in such an ignition trial. The ignition delay time Td starts at point t6, which is the timing when the combustion control device 70 supplies the ignition device 44 with a signal to cause the ignition device 44 to operate, that is, the timing of the ignition command. The ignition delay time Td ends at point t10, which is the timing when the ignition of the main burner 42 is detected based on the detection signal from the flame detector 45, that is, the timing of the ignition detection. The ignition delay time Td is measured by the combustion control device 70 every time an ignition trial is performed, and is output to the ignition delay time monitor 20.

[0044] Furthermore, the combustion control device 70 also stores the time change of the flame activity indicated by the detection signal from the flame detector 45 in the combustion sequence. Here, the detection signal is a voltage signal whose voltage value changes according to the flame activity, but may be a current signal whose current value changes according to the flame activity. In addition, when the flame detector 45 detects the flame activity by discharging when it receives electromagnetic waves such as ultraviolet rays from the flame, the flame activity may be represented by the number of discharges per unit time in the flame detector 45. The voltage signal is also called the flame voltage VF, and the current signal is also called the flame current IF. In the following description, the flame voltage VF and its voltage value can be changed to the flame current IF and its current value. The combustion control device 70 converts the detection signal from the flame detector 45 into an analog-to-digital signal, and stores the time change of the voltage value of the flame voltage VF as flame activity data. The voltage value in the flame activity data represents the flame activity. The combustion control device 70 outputs the stored flame activity data to the ignition delay time monitor 20 .

[0045] Next, the ignition delay time monitoring device 20 will be described. The ignition delay time monitoring device 20 includes various computers such as a personal computer that performs a process of monitoring the ignition delay time. As shown in FIG. 3, the ignition delay time monitoring device 20 includes a processor 21 such as a CPU (Central Processing Unit), a RAM (Random Access Memory) 22 that functions as a main memory for the processor 21, and a storage device 23 that stores a program executed by the processor 21. The storage device 23 also stores a group of ignition delay time data, reference statistical data, most recent statistical data, and a group of flame activity data, which will be described later. The ignition delay time monitoring device 20 further includes a display 24 that displays various screens, which will be described later, an operation device 25 that is operated by a user, and a communication module 26 that allows the processor 21 to communicate with the combustion control device 70.

[0046] In this embodiment, the processor 21 executes a program stored in the storage device 23 to operate as a collection unit 21A, an analysis unit 21B, a comparison unit 21C, and a flame activeness processing unit 21D shown in FIG.

[0047] The collection unit 21A communicates with the combustion control device 70 via the communication module 26, and collects the ignition delay time Td and flame activity data by sequentially acquiring the ignition delay time Td and flame activity data sequentially output by the combustion control device 70. The collection unit 21A stores the sequentially acquired ignition delay time Td and flame activity data in the storage device 23 so that the acquisition order, i.e., the execution order of the ignition trial, can be identified. A set of the ignition delay times Td collected by the collection unit 21A and stored in the storage device 23 is the ignition delay time data group in Fig. 3. Also, a set of the flame activity data stored in the storage device 23 is the flame activity data group.

[0048] The analysis unit 21B shown in Fig. 4 acquires a set of ignition delay times Td for each of a predetermined number of ignition trials performed in the early stage of the combustion device 30 from the ignition delay time data group in the storage device 23. The analysis unit 21B statistically analyzes the acquired set of ignition delay times Td. The analysis unit 21B stores the statistical data of this set obtained by this analysis in the storage device 23 as reference statistical data that serves as a standard for comparison with the most recent statistical data described later.

[0049] The predetermined number of times may be any predetermined number of times necessary for statistical analysis, but here, it is set to 50 times. The initial predetermined number of times refers to, for example, 1st to 50th ignition trials, with the first ignition trial performed after the combustion device 30 is manufactured as the first trial. Manufacturing also includes repairing, repairing, modifying, and replacing the combustion device 30, which makes the combustion device 30 new. The 1st to 50th ignition trials may include ignition trials in an operation test after the combustion device 30 is manufactured. In addition, the initial predetermined number of times may be 1st to 50th, with the first ignition trial performed after the combustion device 30 is sold and installed at a location specified by the user as the first trial. The timing of registering the reference statistical data of the first predetermined number of times, etc., may be specified by the user. The reference statistical data may be generated based on multiple ignition delay times Td of ignition trials performed before the combustion device 30 malfunctions.

[0050] In the statistical analysis by the analysis unit 21B, the number of ignition delay times Td belonging to the same class set in advance is counted as a frequency. The reference statistical data includes distribution data showing the distribution of the number of ignition delay times Td belonging to each class of the ignition delay time Td as shown in FIG. 5. The distribution data is also referred to as reference distribution data hereinafter. The class may be the value of the ignition delay time Td itself. For example, when the ignition delay time Td is specified in units of 1 second and is rounded off to the nearest whole number, each value of 1 second, 2 seconds, 3 seconds, etc. that the ignition delay time Td can take may be treated as a class of the ignition delay time Td. In this case, to be precise, a range of 0.5 seconds or more and less than 1.5 seconds with respect to 1 second can be said to be a class, and each of the seconds 1, 2, 3, etc. can be said to be a class value.

[0051] When the distribution data shown in Fig. 5 is graphed with the horizontal axis representing the class of the ignition delay time Td and the vertical axis representing the number (frequency) of the ignition delay time Td, a graph (frequency line) like that shown in Fig. 6 is obtained. Note that the black circles in the graph in Fig. 6 are attached to the class values. As shown in Fig. 6, the graph of the reference distribution data has a Gaussian distribution with a narrow width in the horizontal axis direction, i.e., a small standard deviation.

[0052] After generating the reference distribution data, the analysis unit 21B statistically analyzes a set of the ignition delay times Td of the ignition trials of the predetermined number of most recent ignition trials (50 trials as described above) among the ignition delay times constituting the ignition delay time data group. The analysis unit 21B stores the statistical data of the set obtained by this analysis in the storage device 23 as the most recent statistical data. The most recent predetermined number of ignition trials are the 50 ignition trials going back from the latest to the 50th trial. The analysis is performed by the same method as that used when obtaining the reference statistical data.

[0053] The most recent statistical data obtained by the above analysis includes distribution data indicating the distribution of the number of ignition delay times Td belonging to each class of ignition delay times Td, similar to the reference statistical data. The distribution data is also called most recent distribution data. If no malfunction occurs in any of the most recent predetermined number of ignition trials, a graph of the most recent distribution data with the ignition delay time on the horizontal axis and the number of ignition trials on the vertical axis will have the same shape as the graph of the reference distribution data.

[0054] In addition, only the latest 50 ignition delay times Td are stored in the storage unit 23, and new ignition delay times Td may overwrite old ignition delay times Td. In this case, reference statistical data may be generated at any timing when 50 ignition delay times are accumulated, and then the latest statistical data may be generated at a timing designated by the user (for example, when a comparison result described later is desired).

[0055] The comparison unit 21C compares the most recent statistical data obtained by the analysis unit 21B with the reference statistical data, and outputs the comparison result. Here, as shown in Figs. 7 to 9, the comparison unit 21C compares the most recent statistical data with the reference statistical data by graphing the most recent distribution data of the most recent statistical data and the reference distribution data of the reference statistical data in association with each other, with the horizontal axis representing the class of the ignition delay time Td and the vertical axis representing the number (frequency) of the ignition delay time Td. Note that, as will be described later in detail, Figs. 7 to 9 show graphs when a malfunction occurs in the combustion device 30. In Figs. 7 to 9, the distribution data are graphed on a common coordinate plane, so that the distribution data are associated with each other. The comparison unit 21C outputs the graphs of the most recent distribution data and the reference distribution data to the display 24 as the comparison result between the most recent statistical data and the reference statistical data, and displays the graphs on the display 24.

[0056] When the combustion device 30 is used for a long period of time, malfunctions may occur in the combustion device 30 due to aging or the like. This malfunction appears as a change in the ignition delay time Td, and the shape of the graph of the most recent distribution data becomes different from the shape of the graph of the reference distribution data.

[0057] When a malfunction occurs in the combustion device 30, the shape of the graph of the most recent distribution data changes as shown in Figs. 7 to 9 depending on the type of malfunction.

[0058] In FIG. 7, the graph of the most recent distribution data is generally shifted to the direction of longer ignition delay time Td compared to the graph of the reference distribution data, and has a large standard deviation. Such malfunctions include (1) disturbances in the ratio of air and fuel gas supplied to the main burner 42 and the pilot burner 43, that is, the air-fuel ratio, and (2) malfunctions of the spark generating part 44A of the ignition device 44, such as bending of the spark generating part 44A. In the above (1), the air-fuel ratio becomes gas-rich or air-rich in the main burner 42 and / or the pilot burner 43. This makes the ignition or ignition timing of each burner 42 or 43 unstable, and the ignition delay time Td tends to become longer. In addition, in the above (2), the energy of the ignition spark becomes smaller, so the ignition timing of the pilot burner 43 is delayed, and as a result, the ignition timing of the main burner 42 is delayed. In addition, even a slight disturbance in the air-fuel ratio that is not as severe as the above (1) leads to an ignition delay. In this way, if the malfunction is the above (1) or (2), the graph of the most recent distribution data will look like Figure 7. A user who checks the comparison result like Figure 7 can infer that either (1) or (2) is occurring.

[0059] Of the above (1) and (2), in (1), the combustion in the main burner 42 is not complete due to the disturbance of the air-fuel ratio. Therefore, the flame of the main burner 42 becomes weaker than in the normal state. On the other hand, in the above (2), since there is no disturbance of the air-fuel ratio, the flame itself does not become weaker. Therefore, when the user obtains a comparison result as shown in FIG. 7, he / she operates the operation device 25 (FIG. 3) to instruct the reading of the flame activity data. In such a case, the flame activity processing unit 21D shown in FIG. 4 displays the flame activity at any time point in each flame activity data on the display 24 based on the flame activity data obtained in the initial ignition trial and the flame activity data obtained in the most recent ignition trial. If this voltage value is lower in the most recent case than in the initial case, the user can infer that the cause of the malfunction is the disturbance of the air-fuel ratio in (1) above. The disturbance of the air-fuel ratio occurs due to malfunctions of the dampers 55 and 65, malfunctions of the blower 62, etc. The user can inspect the dampers 55 and 65, the blower 62, etc. based on the above estimation.

[0060] Comparing the graph of the most recent distribution data in FIG. 8 with the graph of the reference distribution data, the number of mountain peaks in the graph of the reference distribution data is one, but the number of mountain peaks in the most recent distribution data is multiple. Furthermore, the standard deviation is larger in the most recent distribution data. An example of such a malfunction is (3) a malfunction of the spark generating unit 44A of the ignition device 44, such as poor insulation due to soot adhering to the spark generating unit 44A. When such a malfunction occurs, the discharge timing of the spark generating unit 44A of the ignition device 44 becomes unstable, ignition tends to be delayed, the standard deviation of the graph widens, and multiple mountain peaks appear in the graph. When a user checks such a comparison result, a user who checks a comparison result such as that in FIG. 8 can infer that the malfunction of (3) above is occurring.

[0061] In FIG. 9, the graph of the most recent distribution data is generally shifted to the shorter ignition delay time Td side compared to the graph of the reference distribution data. The causes of such malfunction include (4) improper arrangement of the flame detector 45, (5) malfunction of the flame detector 45 such as false discharge, and (6) disturbance of the air-fuel ratio (gas rich). False discharge occurs when the flame detector 45 has a discharge tube that detects electromagnetic waves (e.g., ultraviolet rays) from the flame. The discharge tube generates a discharge when an electromagnetic wave is incident, but due to aging deterioration, etc., it may generate a discharge even when an electromagnetic wave is not incident. This discharge is called a false discharge. The above (4) is a case where the flame detector 45 is poorly positioned and oriented, and an ignition spark is detected. The above (6) is a disturbance when the ratio of combustion gas in the air-fuel ratio increases. A user who confirms the comparison result as shown in FIG. 9 can infer that any of the above malfunctions (4), (5), or (6) is occurring.

[0062] In the above false discharge, the flame activity detected by the flame detector 45 oscillates with time. On the other hand, such oscillation does not occur in the above misalignment (4). Therefore, when the user obtains a comparison result such as that shown in FIG. 9, he / she operates the operation device 25 to instruct the reading of the flame activity data. In such a case, the flame activity processing unit 21D shown in FIG. 4 displays the time change of the voltage value of the flame voltage VF as the time change of the flame activity on the display 24 based on the flame activity data obtained in the most recent ignition trial. If the flame activity oscillates greatly, the user can infer that the malfunction is caused by the above (5).

[0063] As described above, in this embodiment, as a comparison result between the most recent statistical data (first statistical data) obtained by statistically analyzing a set of ignition delay times Td and the reference statistical data (second statistical data) serving as a reference, the graphs of the most recent distribution data and the reference distribution data included in the most recent statistical data and the reference statistical data are displayed superimposed with the horizontal and vertical axes being common. This allows the user to grasp the tendency of malfunction, such as the presence or absence of malfunction in the combustion device 30, by checking the shapes of both graphs. Here, in this embodiment, since the comparison is performed using statistical data obtained by statistically analyzing a set of ignition delay times Td for each of a plurality of ignition trials, the tendency of change in the ignition delay time Td is easily reflected in the comparison result. Therefore, the user can quickly grasp the tendency of malfunction, such as the fact that malfunction is beginning to occur in the combustion device 30, that is, that there is a tendency for malfunction to occur, by checking the comparison result. Furthermore, even if the ignition delay time Td changes significantly due to an unexpected event not resulting from a malfunction of the combustion device 30, the effect of this change is reduced by statistical analysis, so the user can know with high accuracy whether or not there is a malfunction in the combustion device 30. As described above, according to this embodiment, the user can properly understand the malfunction of the combustion device 30 by looking at the comparison results, that is, the graphs of the most recent distribution data and the reference distribution data.

[0064] Recovery from an abnormality such as misfire or flame failure of the combustion device 30 takes time due to the complexity of the devices around the main burner 42. In this embodiment, the user can grasp malfunctions of the combustion device 30 that are a sign of an abnormality in the combustion device 30, making it possible to deal with the abnormality before it occurs.

[0065] Furthermore, in the above embodiment, by displaying graphs of the most recent distribution data and the reference distribution data as the comparison results, the user can infer the type of malfunction from changes in the shape of the most recent distribution data, etc. This improves the efficiency of maintenance of the combustion device 30 and makes it easier to identify the location of the malfunction if an abnormality occurs in the combustion device 30.

[0066] The reference statistical data to be compared with the most recent statistical data may be prepared in advance based on the results of an experiment using a combustion device of the same type as the combustion device 30, but in this embodiment, the reference statistical data is prepared by generating the reference statistical data based on the ignition delay time Td measured in an ignition trial actually performed in the combustion device 30. This makes it possible to obtain reference statistical data that reflects the individual characteristics of the combustion devices 30 that are produced in multiple numbers, allowing the user to more appropriately grasp malfunctions in the combustion device 30.

[0067] The analysis unit 21B may be configured to, for example, statistically analyze a set of ignition delay times Td for each of a plurality of ignition trials and obtain the statistical data of the set as first statistical data (the most recent statistical data in the above), and the analysis method may be arbitrary. Furthermore, the comparison unit 21C may be configured to, for example, compare the first statistical data with second statistical data (the reference statistical data in the above) that serves as a reference prepared as statistical data of a set of ignition delay times when the ignition trials are performed a plurality of times, and output the comparison result. The comparison method and the comparison result may be arbitrary. According to these configurations, it is possible to grasp the tendency of the change in the ignition delay time Td, that is, the tendency of malfunction such as a tendency of malfunction to occur, by statistical analysis, and further, it is possible to reduce the influence of the occurrence of an unexpected event that greatly changes the ignition delay time Td and is not caused by the malfunction of the combustion device 30. Therefore, the user can grasp with high accuracy whether or not a malfunction has occurred in the combustion device 30, and thereby the malfunction of the combustion device 30 can be appropriately grasped.

[0068] (Modification) The configuration of the above embodiment can be modified as desired. Modifications are shown below as examples. Each modification can be combined with at least a portion of the others.

[0069] (Variation 1) The configuration of the combustion device 30 is arbitrary. For example, the combustion device 30 may be a type having only the main burner 42 without the pilot burner 43. Also, the combustion device 30 may be in a state in which the pilot burner 43 is constantly ignited. In this case, it is preferable to prepare a flame detector for the main burner 42 and a flame detector for the pilot burner 43. The ignition delay time Td may be, for example, a period from an ignition instruction that outputs a signal instructing the ignition or ignition of the pilot burner 43 or the main burner 42 to an ignition detection that detects the ignition of the main burner 42.

[0070] (Variation 2) The comparison unit 21C may graph the most recent distribution data of the most recent statistical data and the reference distribution data of the reference statistical data in association with each other, with the vertical axis representing the class of the ignition delay time and the horizontal axis representing the number of ignition delay times. The method of graphing in association is not limited to the method of superimposing each graph on a coordinate plane with a common vertical axis and horizontal axis as described above. For example, each graph may be represented on a different coordinate plane with a common scale of the coordinate axis. In this way, the method of graphing in association may be, for example, a method of graphing each distribution data by a method that allows a user to compare them. Among the set of ignition delay times Td to be the subject of the statistical analysis, ignition delay times Td with suddenly abnormal values ​​may be excluded from the analysis target.

[0071] (Variation 3) The comparison unit 21C may be configured to estimate the presence or absence of a malfunction in the combustion device 30 and the type of the malfunction if a malfunction occurs based on the difference between the most recent statistical data and the reference statistical data, and output the result of the estimation as a comparison result. In this case, the analysis unit 21B may calculate a statistical amount representing the distribution of the ignition delay time Td (including the normalized ignition delay time Td) included in the set of analysis targets in the above statistical analysis. In this case, the most recent statistical data and the reference statistical data include a statistical amount representing the distribution of the ignition delay time Td. The comparison unit 21C may estimate the presence or absence of a malfunction in the combustion device and the type of the malfunction if a malfunction occurs by comparing each statistical amount, and output the result of the estimation as a comparison result.

[0072] An example of the relationship between the comparison result of the statistics and the result of estimating the type of malfunction is shown in FIG. 10. The statistics include, for example, the average value of the ignition delay time Td, the number of ignition delay times Td that take the most frequent value in the distribution of the number of ignition delay times Td that belong to each class of the ignition delay time Td (also called the number of modes), the standard deviation of the distribution, and the number of peaks of the distribution. The average value, number of modes, standard deviation, and number of peaks of the most recent statistical data are called N1, N3, N5, and N7, respectively. The average value, number of modes, standard deviation, and number of peaks of the reference statistical data are called N2, N4, N6, and N8, respectively.

[0073] In the case where the comparison result is shown in Fig. 10, the average value N1 (most recent)>the average value N2 (reference), the number of most recent values ​​N3 (most recent)<the number of most recent values ​​N4 (reference), and the standard deviation N5 (most recent)>the standard deviation N6 (reference), the distribution of the ignition delay time Td is as shown in Fig. 7. Therefore, when the above conditions are satisfied, the comparison unit 21C estimates that there is a malfunction in the combustion device 30, and that the type of the malfunction is a disturbance in the air-fuel ratio or a malfunction of the spark generating unit 44A of the ignition device 44, and outputs that fact (that at least one of the malfunctions has occurred, or that one of the malfunctions has occurred taking other conditions into consideration) as a comparison result (for example, display on the display 24. The same applies to the output of the comparison result below). The comparison unit 21C may estimate and output that the spark generating unit 44A is deformed as a malfunction of the spark generating unit 44A. In addition, if at least one of the following is satisfied: average value N1 (most recent) > average value N2 (reference), number of most recent values ​​N3 (most recent) < number of most recent values ​​N4 (reference), or standard deviation N5 (most recent) > standard deviation N6 (reference), it may be estimated that there is a malfunction in the combustion device 30, and that the type of malfunction is an air-fuel ratio disturbance or a malfunction of the spark generating part 44A of the ignition device 44.

[0074] As described above, in the case of disturbance of the air-fuel ratio, the flame activity decreases. Therefore, the flame activity processing unit 21D compares the flame activity at an arbitrary time point in each flame activity data based on the flame activity data obtained in the initial ignition trial (which may be an initial one or a fixed number of times) as a reference and the flame activity data obtained in the most recent ignition trial (which may be the most recent one or a fixed number of times). If the comparison result shows that the latter is lower than a predetermined standard, the comparison unit 21C may estimate that the type of malfunction is disturbance of the air-fuel ratio. In this way, the comparison unit 21C may estimate that the type of malfunction is disturbance of the air-fuel ratio when the flame activity detected by the flame detector 45 is lower than a predetermined standard.

[0075] The disturbance in the air-fuel ratio may be caused by a malfunction of the blower 62. Therefore, the comparison unit 21C may measure the period from when the blower 62 starts operating to when the air pressure switch 63 is turned on for each ignition trial, and when the period is longer or shorter than a predetermined standard, estimate that the type of malfunction is a disturbance in the air-fuel ratio.

[0076] When the comparison result is standard deviation N5 (last)>standard deviation N6 (reference) and the number of peaks N7 (last)≧2 as shown in FIG. 10, the distribution of the ignition delay time Td becomes as shown in FIG. 8. Therefore, when the above conditions are satisfied, the comparison unit 21C estimates that there is a malfunction in the combustion device 30 and that the type of the malfunction is a malfunction of the spark generating unit 44A of the ignition device 44, and outputs this as the comparison result. At this time, the comparison unit 21C may output that the malfunction of the spark generating unit 44A is an insulation failure. Note that, when at least one of standard deviation N5 (last)>standard deviation N6 (reference) and the number of peaks N7 (last)≧2 is satisfied, it may be estimated that there is a malfunction in the combustion device 30 and that the type of the malfunction is a malfunction of the spark generating unit 44A of the ignition device 44.

[0077] When the comparison result is average value N1 (most recent)<average value N2 (reference) as shown in Fig. 10, the distribution of the ignition delay time Td becomes as shown in Fig. 9. Therefore, when the above condition is satisfied, the comparison unit 21C estimates that there is a malfunction in the combustion device 30 and that the type of the malfunction is a misalignment or malfunction of the flame detector 45, or a disturbance in the air-fuel ratio (gas rich), and outputs that fact (that at least one of the above malfunctions has occurred, or that one of the above malfunctions has occurred taking other conditions into consideration) as a comparison result. At this time, the comparison unit 21C may output that the malfunction of the flame detector 45 is due to a false discharge.

[0078] As described above, in the false discharge, the flame activity varies with time. Therefore, the flame activity processing unit 21D identifies the amplitude (e.g., the maximum amplitude) of the time change of the flame activity based on the flame activity data obtained in the most recent (one or more most recent) ignition trials. If the identified amplitude is greater than a predetermined value, the comparison unit 21C may estimate that the type of malfunction is a malfunction of the flame detector 45. In this way, the comparison unit 21C may estimate that the type of malfunction is a malfunction or false discharge of the flame detector 45 when the amplitude of the flame activity detected by the flame detector 45 is greater than a predetermined standard.

[0079] The comparison unit 21C may calculate and compare statistics for at least one of the relationships between the comparison results of the statistics and the types of malfunctions shown in Fig. 10. The condition for the magnitude of each statistical quantity shown in Fig. 10 may be satisfied when the absolute value of the difference between the statistical quantities to be compared is greater than a predetermined threshold. Other quantities may be adopted as the statistical quantity.

[0080] According to this modification, the user can grasp not only the presence or absence of a malfunction but also an estimated result of the type of malfunction from the output comparison result, so that the user can grasp the malfunction of the combustion device 30 more appropriately.

[0081] (Variation 4) The hardware configuration of the ignition delay time monitoring device 20 is arbitrary. The collecting unit 21A, the analyzing unit 21B, the comparing unit 21C, and the flame activeness processing unit 21D may each be composed of one or more computers or control circuits (such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array)). At least a part of each of the units 21A to 21D may be provided in the combustion control device 70. The ignition delay time monitoring device 20 may be a server computer, a cloud computer, or the like. In these cases, the display 24 on which the comparison results and the like are displayed may be a display of a user terminal or the like. The output destination of various data such as the comparison results or flame activeness data from the comparing unit 21C and the flame activeness processing unit 21D may be a printer, a storage medium, a network, another computer, or the like. Each device such as the ignition delay time monitoring device 20 includes a device in which the components of the device are integrated into one housing, as well as a system in which the components of the device are distributed and accommodated in multiple housings.

[0082] (Ignition delay time monitoring method) The ignition delay time monitoring method includes a process executed by the ignition delay time monitoring device 20 to perform statistical analysis and a comparison between the most recent statistical data and the reference statistical data, but at least a part of the method may be performed by an entity or person other than the ignition delay time monitoring device 20. By checking the comparison result obtained by comparing the most recent statistical data with the reference statistical data, the user can appropriately grasp the malfunction of the combustion device 30 as described above.

[0083] (Scope of the present invention) Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above embodiments and modifications. For example, the present invention includes various modifications to the above embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above embodiments and modifications can be appropriately combined within a range without contradiction. [Explanation of symbols]

[0084] 10...combustion system, 20...ignition delay time monitoring device, 21...processor, 21A...collection section, 21B...analysis section, 21C...comparison section, 21D...flame activity processing section, 23...storage device, 25...operation device, 40...combustion equipment, 42...main burner, 43...pilot burner, 44...ignition device, 44A...spark generating section, 45...flame detector, 50...fuel supply system, 60...air supply system, 70...combustion control device.

Claims

1. A collection unit configured to collect an ignition delay time from an ignition instruction to an ignition detection of an ignition trial for igniting the burner; An analysis unit configured to statistically analyze a set of the ignition delay times of each of the multiple ignition trials collected by the collection unit and obtain statistical data of the set as first statistical data; A comparison unit configured to compare the first statistical data with second statistical data that is prepared as a reference statistical data of a set of ignition delay times when the ignition trial is performed a plurality of times, and to output a comparison result, The first statistical data and the second statistical data include at least one of the number of times that is a mode in a distribution of the number of ignition delay times that belong to each class of ignition delay times and the standard deviation of the distribution, the comparison unit is configured to output, as the comparison result, at least one of a disturbance in an air-fuel ratio, which is a ratio of air to fuel supplied to the burner, and a malfunction of a spark generating unit of an ignition device used to ignite the burner, when the first statistical data is smaller in number than the second statistical data when the number is included in the statistical amount, or when the standard deviation is included in the statistical amount, the standard deviation is larger. Ignition delay time monitor.

2. A collection unit configured to collect an ignition delay time from an ignition instruction to an ignition detection of an ignition trial that ignites a burner; An analysis unit configured to statistically analyze a set of the ignition delay times of each of the multiple ignition trials collected by the collection unit and obtain statistical data of the set as first statistical data; A comparison unit configured to compare the first statistical data with second statistical data that is prepared as a reference statistical data of a set of ignition delay times when the ignition trial is performed a plurality of times, and to output a comparison result, The first statistical data and the second statistical data include at least one of a standard deviation of a distribution of the number of ignition delay times belonging to each class of ignition delay times and a number of peaks in the distribution, When the statistical amount includes the number of peaks, the number of peaks in the second statistical data is one; the comparison unit is configured to output, as the comparison result, a malfunction of a spark generating unit of an ignition device used when igniting the burner when the standard deviation is included in the statistical amount and the standard deviation of the first statistical data is larger than that of the second statistical data, or when the number of peaks is included in the statistical amount and the number of peaks of the first statistical data is multiple. Ignition delay time monitor.

3. The analysis unit is configured to statistically analyze a set of the ignition delay times of the ignition trials performed in the combustion device before a malfunction occurs in the combustion device that is equipped with the burner and performs the ignition trial, which is the same number of ignition trials as the plurality of ignition trials performed in the combustion device, collected by the collection unit, in the same manner as when obtaining the first statistical data, and obtain the statistical data of the set as the second statistical data.

3. The ignition delay time monitoring device according to claim 1 or 2.

4. The first statistical data includes first distribution data indicating a distribution of the number of ignition delay times belonging to each class of ignition delay times, The second statistical data includes second distribution data indicating a distribution of the number of ignition delay times belonging to each class of ignition delay times. The ignition delay time monitoring device according to any one of claims 1 to 3.

5. The comparison unit is A first axis represents the class of the ignition delay time, and a second axis represents the number of the ignition delay time, and the first distribution data and the second distribution data are correlated with each other to create a graph, thereby comparing the first statistical data and the second statistical data; and outputting, as the comparison result, each graph of the first distribution data and the second distribution data graphed in association with each other.

5. The ignition delay time monitoring device according to claim 4.

6. The first statistical data and the second statistical data include an average value of the ignition delay time, the comparison unit is configured to output, when the average value of the first statistical data is shorter than that of the second statistical data, at least one of improper placement of a flame detector used for the ignition detection, a malfunction of the flame detector, and a disturbance in an air-fuel ratio, which is a ratio of air to fuel supplied to the burner, as the comparison result. The ignition delay time monitoring device according to any one of claims 1 to 5.

7. 3. An ignition delay time monitoring program that causes a computer to function as the ignition delay time monitoring device according to claim 1.

8. an analysis step of statistically analyzing a set of ignition delay times from an ignition instruction to an ignition detection for each of a plurality of ignition trials for igniting the burner, and obtaining statistical data of the set as first statistical data; A comparison step of comparing the first statistical data with second statistical data that is prepared as a reference statistical data of a set of ignition delay times when the ignition trial is performed a plurality of times, and obtaining a comparison result, The first statistical data and the second statistical data include at least one of the number of times that is a mode in a distribution of the number of ignition delay times that belong to each class of ignition delay times and the standard deviation of the distribution, In the comparison step, when the number is included in the statistical amount and the first statistical data has a smaller number, or when the standard deviation is included in the statistical amount and the standard deviation is larger, the comparison result indicates at least one of a disturbance in an air-fuel ratio, which is a ratio of air to fuel supplied to the burner, and a malfunction of a spark generating unit of an ignition device used to ignite the burner. Ignition delay time monitoring method.

9. An analysis step of statistically analyzing a set of ignition delay times from an ignition command to an ignition detection for each of a plurality of ignition trials for igniting a burner, and obtaining statistical data of the set as first statistical data; A comparison step of comparing the first statistical data with second statistical data that is prepared as a reference statistical data of a set of ignition delay times when the ignition trial is performed a plurality of times, and obtaining a comparison result, The first statistical data and the second statistical data include at least one of a standard deviation of a distribution of the number of ignition delay times belonging to each class of ignition delay times and a number of peaks in the distribution, When the statistical amount includes the number of peaks, the number of peaks in the second statistical data is one; In the comparison step, when the standard deviation is included in the statistical amount and the standard deviation of the first statistical data is larger than that of the second statistical data, or when the number of peaks is included in the statistical amount and the number of peaks of the first statistical data is more than one, a malfunction of a spark generating unit of an ignition device used to ignite the burner is obtained as the comparison result. Ignition delay time monitoring method.

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