JP2019200045A - Combustor and fan heater - Google Patents

Abstract

To variably set a threshold used for determining ignition, based on a flame detection level.SOLUTION: A control unit comprises: an ignition start unit that when a combustion start operation is received within a predetermined time of driving a fan for cooling a combustion chamber after the combustion of a combustion unit is completed, performs ignition start processing to the combustion unit by an ignition unit; determines an ignition completion threshold based on the detection level of a flame sensor (70) after the reception of the combustion start operation; and determines that ignition is completed when the detection level of the flame sensor after the ignition start processing is equal to or higher than an ignition completion threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a combustion apparatus and a fan heater, and more particularly to a combustion apparatus and a fan heater having a function of determining ignition.

  The gas fan heater determines ignition and extinguishing (misfire) based on the output signal level of a burner sensor (thermocouple) that detects the flame temperature. For example, at the time of ignition, it is detected that ignition has occurred when a predetermined ignition threshold value (eg, burner sensor output is 3 mV) is exceeded. In addition, the level of the output signal of the burner sensor gradually increases after ignition, but if a misfire occurs during combustion (for example, if there is an air trap in the gas pipe and misfires), that point (example: When the burner sensor output starts to decrease from 18 mV) and then decreases by 2 mV (eg, the burner sensor output is 16 mV), it is determined that a misfire has occurred.

  Regarding detection of ignition of a conventional combustion apparatus, Japanese Patent Laying-Open No. 2015-049029 (Patent Document 1) monitors the combustion state of a burner and performs a reignition battle in which the detection level of a flame sensor is higher than a predetermined misfire threshold. Disclosed is a technique for performing a reignition process of a burner by operating a silent igniter when the value becomes lower than the value.

  Japanese Patent Laying-Open No. 2013-217617 (Patent Document 2) discloses a technique for variably setting the soot value (burner sensor misfire determination value) according to the temperature of the upper part of the combustion case.

JP, 2015-049029, A JP 2013-217617 A

  The conventional combustion apparatus has a fixed value (for example, 10 mV) having a margin as a soot value for judging the start of reignition at the time of misfire so that it can be judged even if various conditions such as the type of fuel gas are different. ) Is set. Therefore, even if it can be detected that a misfire has occurred based on the output signal of the burner sensor as in Patent Document 1, the reignition operation is not performed until the level of the output signal drops to 10 mV or less. Whether or not re-ignition has been successful is also determined based on the re-ignition threshold value (eg, 10 mV). Therefore, if the level of the burner sensor output signal has dropped to a value that is considerably lower than the reignition threshold value, even if reignition is actually completed, until the output signal level exceeds the threshold value, It takes a long time until it is determined that the ignition has occurred, and the start of the normal combustion process is delayed, and a spark sound of the ignition device is generated during that time.

  Therefore, an object of an aspect of the present disclosure is to provide a combustion apparatus and a fan heater that can variably set a threshold for determining ignition based on a flame detection level.

  The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention taken in conjunction with the accompanying drawings.

  A combustion apparatus according to an aspect of the present disclosure includes a combustion unit, a switching unit for switching supply of fuel to the combustion unit or stopping of the supply, an ignition unit for igniting the combustion unit, and combustion of the combustion unit A flame sensor for detecting a flame and a control unit for controlling the combustion device are provided.

  The controller is configured to store the fuel sensor while updating the maximum value of the detection level of the flame sensor from the start of ignition to the combustion unit by the ignition unit, in a state where fuel is supplied to the combustion unit by the switching unit, and ignition start If a misfire is detected within a predetermined time from a misfire threshold that is a value obtained by subtracting a predetermined value from the stored maximum value of the flame sensor, the combustion unit by the ignition unit is detected. A re-ignition unit that performs the re-ignition process. The storage unit stores the maximum value while updating the misfire until a misfire is detected.

  The control unit determines a reignition completion threshold based on the detection level of the flame sensor, and determines completion of reignition when the detection level of the flame sensor after the reignition processing is equal to or higher than the reignition completion threshold.

  Preferably, a control part determines the value which added the 1st fixed value to the maximum value of the storage part after misfire as a reignition completion threshold value.

  Preferably, when the detection level of the flame sensor becomes equal to or less than a misfire threshold within a predetermined time from the start of ignition, the re-ignition unit then sets the maximum detection level of the flame sensor after the misfire. When the value becomes equal to or less than the reignition start threshold value obtained by adding the second fixed value to the value, the reignition process is performed.

  Preferably, the first fixed value and the second fixed value are different values.

  Preferably, the reignition completion threshold is a value equal to or greater than the reignition start threshold.

  Said combustion apparatus is further provided with the combustion chamber which accommodates a combustion part, and the fan which ventilates into a combustion chamber. The reignition process includes a fan drive process for driving the fan to have a predetermined rotation number for checking the operation of the fan, and an ignition process for igniting the combustion unit by the ignition unit after the fan drive process. Including. The control unit stores the detection level of the flame sensor at the end of the fan drive process, and determines a value obtained by adding a predetermined third fixed value to the stored detection level as the reignition completion threshold.

  Preferably, the control unit sets, as a reignition completion threshold value, a value that is greater than a detection level of the flame sensor when misfire is detected and is closest to the detection level among a plurality of predetermined values. decide.

  A combustion apparatus according to another aspect includes an operation receiving unit that receives an operation on the combustion apparatus, a combustion unit, a combustion chamber that houses the combustion unit, a fan that blows air into the combustion chamber, and a fuel supply to the combustion unit or the A switching unit for switching supply stop, an ignition unit for igniting the combustion unit, a flame sensor for detecting a combustion flame in the combustion unit, and a control unit for controlling the combustion device .

  The control unit performs ignition start processing for the combustion unit by the ignition unit when a combustion start operation is received within a predetermined time for driving the fan to cool the combustion chamber after the combustion of the combustion unit is completed. Includes ignition start. An ignition completion threshold value is determined based on the detection level of the flame sensor after receiving the combustion start operation, and when the detection level of the flame sensor after the ignition start process is equal to or higher than the ignition completion threshold value, the completion of ignition is determined.

  Preferably, the control unit further includes a storage unit that updates and stores the minimum value of the detection level of the flame sensor from when the combustion start operation is received until the ignition start is detected, and is stored at the end of the ignition start process. A value obtained by adding a predetermined fixed value to the minimum value stored in the unit is determined as the ignition completion threshold.

  Preferably, the control unit sets the value that is greater than the detection level of the flame sensor that is output at the end of the ignition start process and is closest to the detection level among a plurality of predetermined values. Determine the threshold.

  Preferably, the ignition start process includes a fan drive process for driving the motor to have a predetermined rotation number for checking the operation of the fan, and an ignition process for igniting the combustion unit by the ignition unit after the fan drive process. And including. The control unit stores the flame sensor detection level at the end of the fan drive process, and determines a value obtained by adding a predetermined fixed value to the stored detection level as the ignition completion threshold.

  A combustion apparatus according to another aspect includes an operation receiving unit that receives an operation on the combustion apparatus, a combustion unit, a combustion chamber that houses the combustion unit, a fan that blows air into the combustion chamber, and a fuel supply to the combustion unit or A switching unit for switching supply stop, an ignition unit for igniting the combustion unit, a flame sensor for detecting a combustion flame in the combustion unit, and a control unit for controlling the combustion device .

  The control unit is in a state in which fuel is supplied to the combustion unit by the switching unit, and the detection level of the flame sensor is equal to or less than a threshold for determining misfire within a predetermined time from the start of ignition of the combustion unit by the ignition unit In such a case, the reignition unit that performs the reignition process to the combustion unit by the ignition unit, and the combustion start within a predetermined time for driving the fan to cool the combustion chamber after the combustion of the combustion unit is completed And an ignition start unit that performs an ignition start process on the combustion unit by the ignition unit when the operation is accepted.

  When the detection level of the flame sensor after the reignition process is equal to or higher than a predetermined reignition completion threshold, the control unit determines completion of reignition, and sets a plurality of fixed values that are equal to or lower than the reignition completion threshold. Among them, a value that is larger than the detection level of the flame sensor at the time of misfire and that is closest to the detection level is determined as the ignition completion threshold, and the detection level of the flame sensor after the ignition start processing is equal to or higher than the ignition completion threshold. When the ignition is started, the completion of ignition by the ignition start process is determined.

  Preferably, a fan heater provided with said combustion apparatus is provided.

  According to the present disclosure, the threshold for determining ignition is variably set based on the flame detection level.

It is a figure which shows roughly the structure of the combustion apparatus which concerns on each embodiment. It is a figure which shows schematically the structure of the microcomputer 10 of FIG. It is a figure which shows schematically the structure of the function of the gas fan heater 50 which concerns on Embodiment 1. FIG. 3 is a timing chart of reignition according to the first embodiment. 3 is a flowchart of a reignition process at the time of misfire according to the first embodiment. It is a figure which shows schematically the structure of the function of the gas fan heater 50 which concerns on Embodiment 3. FIG. It is a figure which shows schematically the structure of the function of the gas fan heater 50 which concerns on this Embodiment 5. FIG. 10 is a timing chart of ignition during post-purge according to the fifth embodiment. 10 is a flowchart of an ignition process during post-purge according to the fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Embodiment 1]
In the gas fan heater according to the first embodiment, at the time of re-ignition at the time of misfire, the re-ignition is determined based on a calculated value obtained by adding the value of the detection level by the flame sensor and a fixed value unique to the gas fan heater. And the timing for starting or completing the reignition is determined based on the determined threshold.

(Hardware configuration)
FIG. 1 is a diagram schematically showing a configuration of a combustion apparatus according to each embodiment. In the present embodiment, a gas fan heater will be described as an example of a combustion apparatus. As is well known, the gas fan heater performs warm air heating by outputting warm air obtained by the combustion heat of gas as fuel. The fuel is not limited to gas. For example, the following embodiments can be applied even to an oil fan heater.

  With reference to FIG. 1, the gas fan heater 50 constitutes an exterior of the device with an exterior case 66, a top plate 74 and a bottom plate 75. The exterior case 66 has a warm air outlet 65 and an air inlet 67. An air filter 68 is provided at the air suction port 67. A room temperature detector 69 is provided in the vicinity of the air inlet 67. When the power plug 86 is inserted into an outlet (not shown), power is supplied to each part of the gas fan heater 50.

  Inside the exterior case 66, a combustion chamber 62, a blower fan 63 and a fan motor 64 for blowing air into the combustion chamber 62 are provided. In relation to the blower fan 63, a driving fan motor 64 and a rotation speed detector 80 of the fan motor 64 are provided. Inside the combustion chamber 62, there are provided a gas burner 61 that constitutes a combustion part, an ignition part 77 for igniting the gas burner 61, and a flame sensor 70 for detecting the combustion flame of the gas burner 61. The flame sensor 70 includes a thermocouple or the like for detecting a voltage having a magnitude corresponding to the temperature of the combustion flame. The detection level of the flame sensor 70 is indicated as a voltage signal value. The detection level voltage increases as the temperature of the combustion flame increases, and decreases as the temperature of the combustion flame decreases.

  In the gas burner 61, the mixed gas in which the gas and the air sucked by the blower fan 63 are mixed is ignited by a spark (electric spark) from the ignition unit 77. Thereby, ignition to the gas burner 61 by the ignition part 77 is implement | achieved. The combustion heat generated in the combustion chamber 62 due to the combustion of the mixed gas convects in the combustion chamber by the blowing of the blower fan 63. A cover plate 78 is provided on the upper surface and the front surface of the combustion chamber 62. The fan case 79 is configured to guide the warm air convected by the blower fan 63 to the warm air outlet 65.

  The ignition unit 77 includes a spark plug (not shown) and an igniter (not shown). The ignition unit 77 applies a voltage to the ignition plug via the igniter. When a voltage is applied to the spark plug, a spark (electric spark) is generated by a discharge phenomenon that occurs in a region centered on the gap between the electrodes of the spark plug. This spark ignites the mixed gas of the gas burner 61, and the gas burner 61 is ignited (ignited).

  Further, when the ignition is stopped, the ignition unit 77 prohibits application of a voltage to the spark plug via the igniter. Therefore, when the ignition is stopped, the discharge phenomenon and the spark noise are not generated.

  The outer case 66 has a gas connection port 81 for supplying a gas as fuel to the inside at the lower part of the back surface. The gas supplied to the gas connection port 81 includes an electromagnetic valve 45 that is controlled to be opened and closed to supply / shut off the gas, a proportional valve 25 for adjusting a gas pressure (that is, a gas amount per unit time), and a gas. It is supplied to the gas burner 61 via the pipe 84. The electromagnetic valve 45 corresponds to a so-called gas main plug, and the proportional valve 25 corresponds to an adjustment valve that is variably controlled to adjust the gas supply amount from the electromagnetic valve 45 to the gas burner 61. Thus, the electromagnetic valve 45 and the proportional valve 25 correspond to an example of a “switching unit” for switching between supply of fuel to the combustion unit (gas burner 61) and stop of the supply.

  An operation display unit 16 is provided in front of the top plate 74. The operation display unit 16 includes an operation unit 14 (described later), a display unit 15 (described later) such as a liquid crystal for outputting various types of information, a LED (Light Emitting Diode) lamp, and the like. The operation unit 14 includes an operation switch operated to input an operation (combustion) start / stop instruction, and various switches operated to input a setting instruction related to temperature and combustion amount. The operation unit 14 corresponds to an example of an “operation reception unit” for receiving a user operation on the gas fan heater 50.

  The gas fan heater 50 includes a microcomputer (hereinafter abbreviated as “microcomputer”) 10 for controlling the above-described units. The microcomputer 10 is an embodiment of a control unit for centrally controlling and monitoring the gas fan heater 50. FIG. 2 is a diagram schematically showing the configuration of the microcomputer 10 of FIG. Referring to FIG. 2, the microcomputer 10 includes a CPU (Central Processing Unit) 11, a memory unit 12 including a volatile and nonvolatile storage device for storing programs and data, and other units in the gas fan heater 50. Are provided with an interface unit 13, an operation display unit 16 and a timer 17. The display data from the CPU 11 is output to the operation display unit 16, and the display unit 15 is driven based on the display data to display information. Further, the CPU 11 accepts the user's operation contents for the gas fan heater 50 in the operation unit 14.

(Functional configuration)
FIG. 3 is a diagram schematically showing a functional configuration of the gas fan heater 50 according to the present embodiment. Each unit in FIG. 3 is provided as a program executed by the CPU 11. These programs are stored in the memory unit 12 and read and executed by the CPU 11. FIG. 4 is a re-ignition timing chart according to the first embodiment. FIG. 5 is a flowchart of the reignition process at the time of misfire according to the first embodiment. In the present embodiment, ignition of the gas burner 61 at the time of misfire is referred to as “re-ignition”, and is distinguished from the case where ignition is performed in response to the ON operation of the operation switch.

  Referring to FIG. 3, CPU 11 includes a maximum value storage unit 21 and a reignition unit 22. The maximum value storage unit 21 is within a predetermined time (for example, within 20 seconds to 30 seconds) after the ignition of the gas burner 61 by the ignition unit 77 in a state where fuel is supplied to the gas burner 61 by the proportional valve 25. ) Detects the maximum value MAX of the detection level of the flame sensor 70, and stores it in the area E1 of the memory unit 12. The maximum value storage unit 21 stops updating the maximum value MAX when a misfire is detected within the predetermined time. Specifically, the maximum value storage unit 21 inputs the detection level of the flame sensor 70 every 0.1 seconds, for example, and when the detection level value is larger than the previous input value, the maximum value MAX is stored. Is stored in the area E1. When the value of the detection level is smaller than the maximum value MAX, the maximum value MAX in the area E1 is not updated. In this way, the area E1 finally stores the latest maximum value MAX when a misfire is detected.

  In the present embodiment, the latest detection level of the flame sensor 70 is stored in the region E1 within a predetermined time after ignition of the gas burner 61 by the ignition unit 77 is started by turning on the operation switch. Misfire is detected when the value becomes equal to or less than the misfire threshold, which is a value obtained by subtracting a predetermined value ΔmV (eg, 2 mV) from the maximum value MAX. When misfire is detected, the reignition unit 22 performs reignition processing on the gas burner 61 by the ignition unit 77. When the CPU 11 determines that the detection level of the flame sensor 70 after re-ignition is equal to or greater than the ignition completion threshold, which is a value obtained by adding the first fixed value EmV to the maximum value MAX in the region E1, the re-ignition to the gas burner 61 is performed. Determine the completion of ignition. The first fixed value is a value specific to the gas fan heater 50 and is stored in the nonvolatile area of the memory unit 12 at the time of factory shipment. In the present embodiment, EmV is, for example, any value of −5 mV to 5 mV, but the ignition completion threshold is more preferably 3 mV or more in consideration of a noise component or the like of the detection level of the flame sensor 70.

(Timing chart at reignition)
The horizontal axis of the timing chart of FIG. 4 indicates the elapsed time, and the vertical axis indicates the signal levels of the signals A0 to A5. In the figure, signal A 0 indicates the target rotational speed of fan motor 64, signal A 1 indicates the actual rotational speed detected by rotational speed detector 80 of fan motor 64, and signal A 2 is supplied to proportional valve 25. Indicates current. The signal A3 indicates a detection level from the flame sensor 70. Signal A4 indicates the supply current to the electromagnetic valve 45, and signal A5 indicates the voltage of the igniter.

  Referring to FIG. 4, when an operation switch (not shown) of operation unit 14 is turned ON (time T <b> 1), CPU 11 performs (i) fan motor 64 with a predetermined rotation speed in order to start combustion. The initial check is performed to determine whether or not the rotation is possible at the rotation speed. (Ii) When the CPU 11 determines that the rotation of the fan motor 64 is normal based on the output of the rotational speed detector 80 at the time of the initial check, the ignition to the gas burner 61 is performed by the ignition unit 77. In ignition, the CPU 11 causes a relatively large current to flow through the proportional valve 25 in order to forcibly open the proportional valve 25 (time T2). Thereby, even if it is a case where the proportional valve 25 adheres, a valve can be opened. The initial check is an example of “fan drive processing” performed at the time of ignition in order to check whether the fan motor 64 can operate normally.

  Thereafter, the CPU 11 controls to shut off the current to the proportional valve 25 and to close the proportional valve 25 once. In addition, the proportional valve 25 is opened to start ignition, and the ignition unit 77 is controlled to apply a discharge voltage to the ignition plug. When the gas is ignited and combustion is started, it is determined that ignition has occurred when the output of the flame sensor exceeds the initial ignition completion threshold (time T3). After such ignition starts, the maximum value storage unit 21 starts a process of detecting the maximum value MAX based on the detection level of the flame sensor 70 and storing it in the region E1.

  Further, within a predetermined time from the start of ignition, the reignition unit 22 compares the detection level of the flame sensor 70 with the misfire threshold, and determines that the detection level is equal to or less than the misfire threshold based on the comparison result. A misfire is detected (time T5). When misfire is detected, the reignition unit 22 performs reignition processing. The reignition process includes the above-described initial check and ignition process after the end of the initial check (time T6) (ignition operation (time T7) and ignition start by gas amount control in the proportional valve 25 (time T8)).

  The CPU 11 determines the ignition completion threshold value by calculating the maximum value MAX in the region E1. The CPU 11 compares the detection level of the flame sensor 70 after reignition with the ignition completion threshold. Based on the comparison result, when the detection level is equal to or higher than the ignition completion threshold value, it is determined that ignition is complete (time T9). Thereafter, the CPU 11 starts a combustion process. In the combustion process, the igniter is stopped, the target rotational speed is set to the maximum, and the fan motor 64 is started to drive at the maximum target rotational speed.

(Flowchart of reignition processing at the time of misfire)
The reignition process in the case of misfire will be described according to the flowchart of FIG. 5 and referring to the timing chart of FIG. 4 as appropriate.

  Referring to FIG. 5, when the operation switch is turned ON, CPU 11 performs a process PA for starting combustion. Thereby, ignition is detected by the flame sensor 70 (time T1-T3 of FIG. 4). In the process PA, an initial check (step S1) is performed, and then an ignition process is performed. In the ignition process, the proportional valve 25 is forcibly set to the maximum opening and then closed (step S3), the electromagnetic valve 45 is opened, the operation of the ignition unit 77 is started (step S5), and the proportional valve 25 is opened (step S3). Step S7) includes processing.

  Thereafter, the CPU 11 determines whether or not the detection level of the flame sensor 70 satisfies the condition (detection level> initial ignition completion threshold) (step S8). When it is determined that the condition is satisfied (YES in step S8), the process proceeds to step S11 described later.

  On the other hand, when the CPU 11 does not determine that the above condition (detection level> initial ignition completion threshold) is satisfied (NO in step S8), the CPU 11 determines whether a predetermined time has elapsed since the start of ignition ( Step S9). When it is determined that the predetermined time has not elapsed (NO in step S9), the process returns to step S7, and the subsequent processing is similarly repeated. On the other hand, when the CPU 11 determines that the above condition is not satisfied for the detection level of the flame sensor 70 within a predetermined time from the start of ignition (NO in step S8, YES in step S9), error processing (step After S10), a series of processing is terminated.

  The maximum value storage unit 21 of the CPU 11 detects the maximum value MAX described above after the start of ignition and stores it in the region E1 (step S11). The reignition unit 22 determines whether or not the detection level of the flame sensor 70 is equal to or less than the misfire threshold, which is a value obtained by reducing the misfire threshold ΔmV from the maximum value MAX of the region E1 within a predetermined time from the start of ignition. Judgment is made (NO in step S13 and step S15). If it is determined that the detection level is not equal to or less than the misfire threshold within a predetermined time (YES in step S15), a combustion process (step S29) is performed.

  On the other hand, if it is determined that the detection level of the flame sensor 70 is equal to or less than the misfire threshold (YES in step S13, see times T4 and T5 in FIG. 4), misfire is detected, and the CPU 11 detects the proportional valve 25 and the electromagnetic The valve 45 is closed (step S17). At this time, the CPU 11 calculates the ignition completion threshold (ignition completion threshold = maximum value MAX + EmV) using the maximum value MAX of the region E1. Thereby, the ignition completion threshold value is determined.

  When misfire is detected, the reignition unit 22 performs the above-described process PA in order to reignite (step S21). As a result, the reignition process is performed (see times T6 to T8 in FIG. 4).

  After the reignition process is performed, the CPU 11 satisfies the condition (detection level ≧ ignition completion threshold) for the detection level input from the flame sensor 70 within the predetermined time (NO in step S25). Whether or not (step S23). While it is determined that this condition is not satisfied (NO in step S23), the process of step S23 is repeated within the predetermined time (NO in step S25).

  On the other hand, if it is determined that the above condition is satisfied within the predetermined time (YES in step S23, NO in step S25), the CPU 11 determines that the reignition is completed (time T9 in FIG. 4). (See), combustion processing is started (step S29).

  If the completion of reignition is not determined within a predetermined time (YES in step S25), the CPU 11 performs an error process (step S27) and ends the series of processes. The error processing in step S10 and step S27 includes, for example, message display on the display unit 15, stop of gas supply to the gas burner 61, and stop of ignition by the ignition unit 77.

  According to the reignition processing of FIGS. 4 and 5, the ignition completion threshold for determining completion of reignition can be variably set based on the detection level of the flame sensor 70. Therefore, compared with the conventional case where the reignition completion threshold is set to a fixed value, the required time from the misfire or reignition until the combustion process is started is shortened, and the combustion process is started immediately. It becomes possible.

[Embodiment 2]
In the second embodiment, a modification of the first embodiment will be described. In the second embodiment, an ignition start threshold value for starting reignition is determined, and reignition is started based on the ignition start threshold value.

  In the second embodiment, when a misfire is detected within a predetermined time from the start of ignition (step S5 in FIG. 5), the reignition unit 22 determines that the detection level of the flame sensor 70 is equal to or less than the ignition start threshold. Then, a reignition process (step S21 in FIG. 5) is performed. The ignition start threshold is a value obtained by adding the second fixed value to the maximum value MAX of the region E1 (that is, the maximum value MAX when misfire is detected).

  The second fixed value is stored in the nonvolatile area of the memory unit 12 when the gas fan heater 50 is shipped from the factory. The second fixed value is one of −5 mV to 5 mV, similar to the first fixed value for the ignition completion threshold.

  Preferably, the first fixed value and the second fixed value are set such that the ignition completion threshold is equal to or greater than the ignition start threshold. That is, even after the reignition process (process PA in step S21) is started, the detection level of the flame sensor 70 continues to decrease during the initial check, so even if reignition (ignition process in process PA) is performed, It takes time before the detection level starts to rise. Therefore, by setting the ignition completion threshold value to the same value as the ignition start threshold value, the time required from the start of reignition until the completion of ignition can be shortened.

  In addition, when the first fixed value and the second fixed value are set to values at which the ignition completion threshold value is larger than the ignition start threshold value, the first fixed value and the second fixed value are related to noise that may be included in the detection level of the flame sensor 70. Instead, the ignition completion threshold value can be determined to a value for reliably determining completion of ignition.

  More preferably, the first fixed value for calculating the ignition completion threshold is set to a positive value, and the second fixed value for calculating the ignition start threshold is set to a negative value. Thereby, the start of reignition can be performed at an early stage from the misfire, and then the completion of reignition can be determined when the flame becomes stable.

[Embodiment 3]
In the third embodiment, unlike the first and second embodiments, the ignition completion threshold value is determined using the detection level of the flame sensor 70 at the end of the initial check performed at the time of re-ignition.

  FIG. 6 is a diagram schematically illustrating a functional configuration of the gas fan heater 50 according to the third embodiment. Each unit in FIG. 6 is provided as a program executed by the CPU 11. These programs are stored in the memory unit 12 and read and executed by the CPU 11.

  Referring to FIG. 6, CPU 11 includes a maximum value storage unit 21 for storing the maximum value MAX while updating it, a reignition unit 22 for performing a reignition process, and a level storage unit 24. Maximum value storage unit 21 and reignition unit 22 are the same as those shown in FIG. 3, and therefore description thereof will not be repeated.

  The level storage unit 24 detects the detection level CV of the flame sensor 70 at the end of the initial check for reignition and stores it in the area E2 of the memory unit 12. The CPU 11 determines a calculated value obtained by adding a predetermined fixed value (for example, any value of EmV = −5 mV to +5 mV) to the detection level CV of the region E2 as the ignition completion threshold value. When the CPU 11 compares the detection level of the flame sensor 70 after re-ignition by the process PA at the time of misfire and the ignition completion threshold, and determines based on the comparison result that the detection level is equal to or higher than the ignition completion threshold, Determine completion of reignition. When the completion of reignition is determined, the CPU 11 starts a combustion process.

  In the third embodiment, the reignition unit 22 starts the reignition process when a misfire is detected. As in the first and second embodiments, the reignition unit 22 determines the reignition start timing based on the ignition start threshold. It is good. In other words, the reignition unit 22 has a maximum value when the detection level of the flame sensor 70 is equal to or lower than the misfire threshold within a predetermined time from the start of ignition (for example, 20 seconds to 30 seconds) and misfire is detected. A value obtained by adding a fixed value EmV to MAX is determined as an ignition start threshold value. When the reignition unit 22 determines that the detection level of the flame sensor 70 is equal to or higher than the ignition start threshold after misfire is detected, the reignition unit 22 starts the reignition process.

  As described above, in the third embodiment, the detection level of the flame sensor 70 for determining the ignition completion threshold value may be acquired only by the detection level CV at the end of the initial check. It can be simplified.

[Embodiment 4]
In the fourth embodiment, unlike the first to third embodiments, the ignition completion threshold value for reignition is determined based on the detection level of the flame sensor 70 by selecting from a plurality of predetermined values. . Since the other processes except the method for determining the ignition completion threshold are the same as those shown in the above embodiment, description thereof will not be repeated.

  In the present embodiment, the plurality of values are stored in advance in the nonvolatile area of the memory unit 12 when the gas fan heater 50 is shipped from the factory. For example, the plurality of values are determined by experiments based on the characteristics of the gas fan heater 50 (the type of gas, the minimum value to the maximum value of the detection level that can be output by the flame sensor 70, etc.).

  Specifically, the CPU 11 stores the detection level of the flame sensor 70 in the memory unit 12 when a misfire is detected. Further, the CPU 11 selects a value that is larger than the detection level at the time of misfire and is closest to the detection level from the plurality of values of the memory unit 12, and sets the selected value as the ignition completion threshold value. decide.

  In each of the above embodiments, the ignition completion threshold value and the ignition start threshold value are set to 3 mV or more. Therefore, at the time of misfire, the reignition operation can be started immediately without waiting for the detection level of the flame sensor 70 to fall below the ignition start soot value (3 mV or more). Further, the ignition start threshold value and the ignition completion threshold value can be set to close values according to the value of EmV. As a result, the completion of reignition after the start of reignition can be promptly performed.

[Embodiment 5]
In the fifth embodiment, a method for determining an ignition completion threshold for determining the completion of ignition when the operation switch is turned on (OFF → ON) during post-purge will be described.

  Post-purge means that the fan motor 64 is driven to cool the inside of the combustion chamber 62 when the operation switch is turned OFF during combustion and the supply of gas to the gas burner 61 is stopped (combustion end). This refers to the operating state in which air is blown. In the present embodiment, the post-purge is performed for a predetermined time (for example, 150 seconds) from the end of combustion by the operation switch OFF operation.

  In the fifth embodiment, instead of the maximum value MAX of the first embodiment, the minimum value of the detection level of the flame sensor 70 during the post purge is detected, and the ignition completion threshold value is determined using the detected minimum value. . Specifically, the CPU 11 determines the ignition completion threshold based on the detection level of the flame sensor 70 after receiving the operation switch ON operation (combustion start operation) during the post purge. And when the detection level of the flame sensor 70 after the ignition start process implemented according to combustion start operation becomes more than an ignition completion threshold value, it determines with ignition having been completed.

(Functional configuration)
FIG. 7 is a diagram schematically showing a functional configuration of the gas fan heater 50 according to the fifth embodiment. Each unit in FIG. 7 is provided as a program executed by the CPU 11. These programs are stored in the memory unit 12 and read and executed by the CPU 11. FIG. 8 is a timing chart of ignition during post purge according to the fifth embodiment. FIG. 9 is a flowchart of the ignition process during the post purge according to the fifth embodiment.

  Referring to FIG. 7, CPU 11 includes a minimum value storage unit 26 and an ignition start unit 27. The minimum value storage unit 26 detects the minimum value MIN of the detection level of the flame sensor 70 from when the operation start operation during post purge is received until the ignition process is started, and the detected minimum value MIN is stored in the memory unit. 12 areas E3. Specifically, the minimum value storage unit 26 inputs the detection level of the flame sensor 70, for example, every 0.1 second. When the detection level value is smaller than the previous input value, the minimum input value is set to the minimum value. Stored in the area E3 as the value MIN. As described above, the minimum value of the detection level is stored while being updated in the region E3. After the ignition is started, the minimum value MIN in the region E2 indicates the minimum value when the ignition start is detected.

  When the user's operation switch ON operation (combustion start operation) is accepted during the post purge, the ignition start unit 27 stops driving the fan motor 64, and then the ignition start process to the gas burner 61 by the ignition unit 77 is performed. To do. At the end of the ignition start process, the CPU 11 determines a value obtained by adding a predetermined positive fixed value (for example, 0 mV <fixed value ≦ + 5 mV) to the minimum value MIN of the region E3 as the ignition completion threshold value. When the detection level of the flame sensor 70 becomes equal to or higher than the ignition completion threshold after the ignition start process by the ignition start unit 27, the ignition completion is determined and the above-described combustion process is started.

(Timing chart during ignition during post-purge)
In the timing chart of FIG. 8, the horizontal axis indicates the elapsed time, and the vertical axis indicates the signal levels of the signals A0 to A5. In the figure, signals A0 to A5 are the same as those shown in FIG. 4, and therefore description thereof will not be repeated.

  In FIG. 8, when the operation switch (not shown) of the operation unit 14 is turned off during combustion and post-purge is started and the operation switch is continuously turned on (time t <b> 1), the CPU 11 detects the fan motor 64. Is stopped, ignition start processing by the ignition start unit 27 is performed. Specifically, the ignition start process is performed when (i) the initial check (time t2) and the output of the rotational speed detector 80 at the time of the initial check are determined that the rotation of the fan motor 64 is normal. (Ii) ignition processing (time t3, t4). In the ignition process, the proportional valve 25 and the electromagnetic valve 45 are controlled so as to supply gas to the gas burner 61, and the gas burner 61 is ignited by the ignition unit 77.

  The minimum value storage unit 26 starts a process of storing the minimum value MIN in the region E3 after the operation switch is turned ON during the post purge.

  The CPU 11 determines an ignition completion threshold value at the end of the ignition start process, and then determines completion of ignition when the detection level of the flame sensor 70 becomes equal to or higher than the ignition completion threshold value (time t5). When the completion of ignition is determined, the CPU 11 starts a combustion process.

  Here, the CPU 11 determines a value obtained by adding a predetermined positive fixed value to the minimum value MIN of the region E3 at the end of the ignition start process as the ignition completion threshold.

(Processing flowchart in post-purge)
The post-purge process will be described with reference to the timing chart of FIG. 8 according to the flowchart of FIG.

  In a predetermined time (for example, 150 seconds) for performing the post purge, the CPU 11 determines whether or not the operation switch is turned on (OFF → ON) based on the input from the operation unit 14 (step S31, S31). NO in step S33).

  If it is determined that the operation switch is not turned ON during the post purge (NO in step S31, YES in step S33), the series of processes ends. On the other hand, if it is determined that the operation switch has been turned on (NO in step S33, YES in step S31), the minimum value storage unit 26 starts storing the minimum value MIN in the region E3 (step S35). CPU11 controls each part so that process PA including an ignition process may be implemented (time t1-t5).

  By performing the processing PA, the gas burner 61 is ignited by the ignition unit 77, and combustion starts.

  At the end of the process PA (more specifically, the ignition start process), the CPU 11 calculates and determines the ignition completion threshold as described above (step S37). The CPU 11 inputs the detection level of the flame sensor 70, and determines whether or not the condition (detection level ≧ ignition completion threshold) is satisfied for the input detection level (step S39). While the condition is not satisfied (NO in step S39), the process of step S37 is repeated.

  If it is determined that the above condition is satisfied (YES in step S39, refer to time t5 in FIG. 8), the CPU 11 determines that the ignition is completed and starts the combustion process described above (step S41).

  As described above, in the present embodiment, a value obtained by adding a predetermined fixed value to the minimum value MIN stored in the region E2 at the end of the ignition start process is determined as the ignition completion threshold value.

[Embodiment 6]
In the sixth embodiment, unlike in the fifth embodiment, the ignition completion threshold for determining the completion of ignition during post-purge is selected from a plurality of predetermined values based on the detection level of the flame sensor 70. Determine by making a selection. Since the other processes except the ignition completion threshold determination method are the same as those shown in the fifth embodiment, the description thereof will not be repeated.

  The plurality of values are values stored in advance in the nonvolatile area of the memory unit 12 when the gas fan heater 50 is shipped from the factory. For example, the plurality of values are values determined by experiments based on the characteristics of the gas fan heater 50 described above.

  In the present embodiment, the CPU 11 has a value larger than the detection level of the flame sensor that is output at the end of the ignition start process among a plurality of predetermined values in the memory unit 12, and is the highest in the detection level. A close value is selected, and the selected value is determined as the ignition completion threshold.

[Embodiment 7]
In the seventh embodiment, the ignition completion threshold is determined by a method different from the fifth and sixth embodiments. Specifically, the ignition completion threshold is determined using the detection level of the flame sensor 70 at the end of the initial check in the ignition start process performed by the ignition start unit 27.

  The ignition start process performed by the ignition start unit 27 is a process PA. As described above, the initial check and the ignition process for igniting the gas burner 61 by the ignition unit 77 after the completion of the initial check are performed. Including.

  The CPU 11 inputs the detection level of the flame sensor 70 at the end of the initial check, and stores it in the memory unit 12. The CPU 11 determines a value obtained by adding a predetermined fixed value (any value of EmV = −5 mV to +5 mV) to the detection level stored in the memory unit 12 as the ignition completion threshold value. The CPU 11 inputs the detection level of the flame sensor 70 after the ignition start process, and determines completion of ignition when it is determined that the input detection level is equal to or higher than the ignition completion threshold. When the CPU 11 determines the completion of ignition, the CPU 11 starts the combustion process.

  Thus, in the seventh embodiment, the acquisition of the detection level of the flame sensor 70 for calculating the ignition completion threshold may be performed once at the end of the initial check, so that the minimum value is obtained as in the fifth and sixth embodiments. The process for determining the ignition completion threshold can be simplified as compared with the case where the MIN is acquired while being updated.

[Embodiment 8]
The combustion apparatus shown in FIG. 1 and FIG. 2 starts ignition by the function of determining the reignition completion threshold for reignition at the time of misfire (Embodiments 1 to 4) and operation switch operation during post purge. It may be configured to include both of the functions (Embodiments 5 to 7) for determining the ignition completion threshold in the case.

  As an example of a combustion apparatus having both the above functions, an ignition completion threshold value (hereinafter referred to as a value B) for determining completion of ignition during post-purge is selected from a plurality of predetermined values. A method of determining using the reignition completion threshold at the time of misfire will be described. The plurality of predetermined values are acquired by experiments based on the characteristics of the gas fan heater 50 as described above, and stored in the memory unit 12 at the time of factory shipment or the like.

  First, the CPU 11 detects the detection level of the flame sensor 70 when the misfire is detected (hereinafter referred to as level BS) and the reignition completion threshold (hereinafter referred to as value A) determined by any one of the first to fourth embodiments. (≦ value of level BS) is stored in the memory unit 12. Thereafter, when the CPU 11 accepts the operation switch ON operation during the post purge, the ignition start unit 27 performs an ignition start process. The CPU 11 determines an ignition completion threshold for determining the completion of ignition by the ignition start process using the reignition completion threshold (value A) as follows.

  First, the CPU 11 selects one or more values that are equal to or less than the value A among a plurality of values stored in advance in the memory unit 12. Then, among the selected values, a value that is larger than the value of the level BS and closest to the value of the level BS is extracted, and the extracted value is determined as an ignition completion threshold (value B) (however, Reignition completion threshold (value A)> ignition completion threshold (value B)).

  More specifically, it is assumed that values B1, B2, and B3 that are equal to or less than the value A are selected from a plurality of values stored in advance in the memory unit 12. However, there is a relationship of 3 mV <B1 <B2 <B3 ≦ A. The value of the level BS at the time of misfire is a value B1 when BS <B1, a value B2 when B1 ≦ BS <B2, a value B3 when B2 ≦ BE <B3, a value A when B3 ≦ BS, Each is extracted, and the extracted value is determined as the ignition completion threshold. When the CPU 11 determines that the detection level of the flame sensor 70 is equal to or higher than the determined ignition completion threshold, the CPU 11 determines that the ignition has been completed.

[Effect of the embodiment]
According to each embodiment, the threshold value for determining the start or completion of ignition can be set to a value corresponding to the detection level of the flame sensor 70 in reignition at the time of misfire or ignition during post purge. . Therefore, the threshold value can be variably set according to the difference in combustion conditions such as the type of gas. As a result, it is possible to start the early combustion process without waiting for the detection level of the flame sensor 70 to fall below the fixed threshold value as in the prior art, and the igniter is activated for a long time during ignition. It is also possible to prevent the operation (preventing the generation of ignition sound associated therewith), and the usability of the combustion apparatus is improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

10 microcomputer, 12 memory unit, 13 interface unit, 14 operation unit, 15 display unit, 16 operation display unit, 17 timer, 21 maximum value storage unit, 22 reignition unit, 24
Level storage unit, 25 proportional valve, 26 minimum value storage unit, 27 ignition start unit, 45 solenoid valve, 50 gas fan heater, 61 gas burner, 62 combustion chamber, 63 blower fan, 64
Fan motor, 65 Air outlet, 66 Exterior case, 67 Air inlet, 68 Air filter, 69 Room temperature detector, 70 Flame sensor, 74 Top plate, 75 Bottom plate, 77 Ignition part, 78 Cover plate, 79 Fan case, 80 Rotation Number detector, 81 gas connection port, 84 gas piping, 86 power plug, E1, E2, E3 area, PA treatment.

Claims (6)

A combustion device,
An operation receiving unit for receiving an operation on the combustion device;
A combustion section;
A combustion chamber that houses the combustion section;
A fan for blowing air into the combustion chamber;
A switching unit for switching between supply of fuel to the combustion unit or stop of the supply;
An ignition unit for igniting the combustion unit;
A flame sensor for detecting a combustion flame in the combustion section;
A control unit for controlling the combustion device,
The controller is
When a combustion start operation is received within a predetermined time for driving the fan to cool the combustion chamber after the combustion of the combustion section is completed, an ignition start process for the combustion section by the ignition section is performed. Including an ignition start to perform,
An ignition completion threshold is determined based on the detection level of the flame sensor after receiving the combustion start operation, and when the detection level of the flame sensor after the ignition start process is equal to or higher than the ignition completion threshold, the completion of ignition is determined. Judge the combustion device. The controller is
A storage unit for storing the flame sensor while updating the minimum value of the detection level of the flame sensor until the start of ignition is detected after the combustion start operation is received,
The combustion apparatus according to claim 1, wherein a value obtained by adding a predetermined fixed value to the minimum value stored in the storage unit at the end of the ignition start process is determined as the ignition completion threshold value.   The control unit determines a value that is greater than a detection level of the flame sensor that is output at the end of the ignition start process and is closest to the detection level, from among a plurality of predetermined values. The combustion apparatus of claim 1, wherein the combustion apparatus determines a completion threshold. The ignition start process includes a fan drive process for driving the fan to have a predetermined rotational speed for checking the operation of the fan, and an ignition for igniting the combustion unit by the ignition unit after the fan drive process. Processing, and
The controller is
Stores the detection level of the flame sensor at the end of the fan drive process,
The combustion apparatus according to claim 1, wherein a value obtained by adding a predetermined fixed value to the stored detection level is determined as the ignition completion threshold value. A combustion device,
An operation receiving unit for receiving an operation on the combustion device;
A combustion section;
A combustion chamber that houses the combustion section;
A fan for blowing air into the combustion chamber;
A switching unit for switching between supply of fuel to the combustion unit or stop of the supply;
An ignition unit for igniting the combustion unit;
A flame sensor for detecting a combustion flame in the combustion section;
A control unit for controlling the combustion device,
The controller is
As a state in which fuel is supplied to the combustion unit by the switching unit, the detection level of the flame sensor determines a misfire within a predetermined time from the start of ignition of the combustion unit by the ignition unit. A re-ignition unit that performs re-ignition processing to the combustion unit by the ignition unit, when
When a combustion start operation is received within a predetermined time for driving the fan to cool the combustion chamber after the combustion of the combustion section is completed, an ignition start process for the combustion section by the ignition section is performed. An ignition start portion to perform,
The controller is
When the detection level of the flame sensor after the reignition process is equal to or higher than a predetermined reignition completion threshold, it is determined that reignition is complete,
Of a plurality of fixed values that are equal to or less than the reignition completion threshold, a value that is greater than the detection level of the flame sensor at the time of the misfire and is closest to the detection level is determined as the ignition completion threshold,
A combustion apparatus that determines completion of ignition by the ignition start process when a detection level of the flame sensor after the ignition start process is equal to or higher than the ignition completion threshold.   A fan heater provided with the combustion apparatus of any one of Claim 1 to 5.

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