JP2015094495A - Firing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a firing apparatus capable of setting an accidental-fire monitoring circuit in an accidental-fire detectable state when supply of electric power from a battery starts, and allowing a microcomputer to recognize that a solenoid valve is opened by the accidental-fire monitoring circuit.SOLUTION: A microcomputer 50 outputs a charging pulse signal from an output port Po1 and a charging acceleration signal from an output port Po2 and sets a charge current for charging a capacitor 120 from a charge circuit 140 to a first charge current if being actuated in response to start of supply of electric power from a battery 30, and stops outputting the charge acceleration signal and sets the charge current to a second charge current lower than the first charge current after a voltage Vc across terminals of the capacitor 120 is equal to or higher than an accidental-fire determinable level.

Description

  The present invention relates to a combustion apparatus having a burner misfire detection function.

  2. Description of the Related Art Conventionally, for example, in a gas combustion apparatus, a combustion sensor that detects the combustion state of a burner is provided, and a microcomputer that controls the operation of the combustion apparatus detects a burner misfire by a detection signal of the combustion sensor. The solenoid valve provided in the gas supply pipe connected to is closed to stop the fuel supply to the burner. However, with this configuration, if a failure occurs in the connection circuit between the combustion sensor and the microcomputer during combustion of the burner, it becomes impossible to detect the misfire of the burner and stop the supply of fuel gas. .

  Therefore, a configuration is proposed in which a misfire monitoring circuit that operates separately from the microcomputer, monitors the presence or absence of burner misfire from the detection signal of the combustion sensor, and closes the solenoid valve when the burner misfire is detected is proposed. (For example, refer to Patent Document 1).

JP 2004-69077 A

  When the misfire monitoring circuit described above is configured by a hardware circuit, the state in which the detection signal of the combustion sensor has reached the misfire detection level has continued for a predetermined time or longer by a discharge timer using a capacitor, and It is conceivable to adopt a configuration that cuts off the power supply to the drive coil.

  And in the combustion device that uses the battery as a power source and starts supplying power from the battery according to the operation of the power switch by the user, when the power switch is operated, the capacitor of the discharge timer is quickly charged, It is desirable that a misfire can be detected by the misfire monitoring circuit. When the solenoid valve is closed by the misfire monitoring circuit, it is desirable that the microcomputer recognize that the burner has misfired and stop the opening control of the solenoid valve by the microcomputer.

  The present invention has been made in view of such a background, and when power supply from a battery is started in response to an ignition operation, the misfire monitoring circuit is quickly made to be capable of detecting misfire, and the misfire monitoring circuit It is an object of the present invention to provide a combustion apparatus that allows a microcomputer to recognize that a solenoid valve is closed.

The present invention has been made to achieve the above object,
A combustion apparatus that operates with electric power supplied from a battery and starts supplying electric power from the battery according to a user's operation,
With a burner,
An electromagnetic valve for opening and closing a fuel supply path connected to the burner;
A solenoid valve drive circuit that opens and closes the solenoid valve by switching between energization and de-energization of the drive coil of the solenoid valve;
A combustion state detector for detecting the combustion state of the burner;
An open / close state detection unit for detecting an open / close state of the solenoid valve;
When it is in a misfire determination state in which it is detected that the solenoid valve is open by the capacitor and the open / close state detection unit, and the burner is detected to be extinguished by the combustion state detection unit A discharging circuit for discharging the capacitor; a charging circuit for charging the capacitor when not in the misfire determination state; and when the voltage across the capacitor is shifted from a state lower than a first threshold to a high state, Switching from a non-energized state where the energization to the drive coil of the solenoid valve is impossible to an energizable state where the energization is possible, and in the energized state, the voltage across the terminals of the capacitor is less than or equal to a second threshold value lower than the first threshold A misfire monitoring circuit having an energization switching circuit for switching from the energized state to the unenergized state when
The charging current supplied from the charging circuit to the capacitor is defined as a first charging current when power supply from the battery is started, and the capacitor is charged by the first charging current between the terminals of the capacitor. A charging current switching unit that sets a charging current of the capacitor to a second charging current smaller than the first charging current after the voltage is equal to or higher than the misfire determination possible voltage set to the first threshold or more;
After the power supply from the battery is started and the voltage between the terminals of the capacitor becomes equal to or higher than the misfire determination voltage, the solenoid valve is opened by the solenoid valve driving circuit and the burner combustion operation is started. When the burner misfire is detected by the combustion state detector during the combustion operation, and when the solenoid valve is closed by the open / close state detector during the combustion operation, the electromagnetic And a microcomputer that stops energization of the drive coil of the solenoid valve by the valve drive circuit.

  In the combustion apparatus of the present invention, power supply from the battery is started in response to a user operation, and the capacitor of the misfire monitoring circuit is charged by the charging circuit. Then, after the voltage between the terminals of the capacitor becomes equal to or higher than the misfire determination possible voltage, the microcomputer starts the combustion operation of the burner.

  When a failure occurs in the detection signal input circuit from the combustion state detection unit to the microcomputer, the microcomputer cannot recognize that the burner has misfired. In this case, when the misfire of the burner occurs, the microcomputer cannot close the solenoid valve, but the capacitor of the misfire monitoring circuit is discharged by the discharge circuit. Then, when the voltage between the terminals of the capacitor becomes equal to or lower than the second threshold value, the energization switching circuit stops energizing the drive coil of the solenoid valve, the solenoid valve is closed, and the fuel gas to the burner Supply stops.

  As described above, when the solenoid valve is closed, the open / close state detection unit detects that the solenoid valve is in the closed state and is not in the misfire determination state. Therefore, the charging circuit charges the capacitor. Is started, and when the voltage between the terminals of the capacitor shifts from a state lower than the first threshold to a state exceeding the first threshold, the energization switching circuit switches the energization prohibited state to the energization permitted state. It is done. When the energization permission state is established, if the microcomputer continues to be energized to the drive coil of the solenoid valve by the solenoid valve drive circuit, the solenoid valve is opened. I will return.

  Therefore, the charging current switching unit sets the energization current of the capacitor as the first charging current when the power supply from the battery is started, and after the terminal voltage of the capacitor becomes equal to or higher than the misfire determination possible level. Is a second charging current smaller than the first current. As a result, when the power supply from the battery is started, the capacitor of the misfire monitoring circuit can be quickly charged, and the misfire monitoring circuit can be quickly made ready for handling misfire. In addition, when a misfire occurs during the burn operation of the burner, the microcomputer gradually recognizes that the solenoid valve is in a closed state by the open / closed state detector by slowing the rise in the voltage across the capacitor. Therefore, it is possible to secure time for the operation, stop energization of the electromagnetic valve, and maintain the electromagnetic valve in a closed state.

The block diagram of a combustion apparatus. The block diagram of a controller. The timing chart of a microcomputer and a misfire monitoring circuit.

  An example of an embodiment of the present invention will be described with reference to FIGS.

  With reference to FIG. 1, the combustion apparatus of the present embodiment is a gas stove including a first burner 10 and a second burner 20, and the operation of the first burner 10 and the second burner 20 is controlled by the controller 1.

  The gas supply path 5 for supplying the fuel gas to the first burner 10 and the second burner 20 branches into a first gas supply path 5a and a second gas supply path 5b, and the first gas supply path 5a is the first burner 10. And the second gas supply path 5 b is connected to the second burner 20. The gas supply path 5, the first gas supply path 5a, and the second gas supply path 5b correspond to the fuel supply path of the present invention.

  The gas supply path 5 is provided with an original gas valve 6 that opens and closes the gas supply path 5. The first gas supply path 5a includes a first electromagnetic valve 11 (corresponding to an electromagnetic valve of the present invention) that opens and closes the first gas supply path 5a, and an opening degree of the first gas supply path 5a. A first flow rate control device 12 that changes the supply flow rate of the fuel gas to the burner 10 is provided.

  Further, in the vicinity of the first burner 10, a first ignition electrode 14 for igniting the first burner 10, and a first thermocouple 13 for detecting the combustion state of the first burner 10 (in the combustion state detection unit of the present invention). Corresponding).

  Similarly, in the second gas supply path 5b, the opening degree of the second electromagnetic valve 21 (corresponding to the electromagnetic valve of the present invention) for opening and closing the second gas supply path 5b and the second gas supply path 5b are changed. And a second flow rate control device 22 for changing the supply flow rate of the fuel gas to the second burner 20. Further, in the vicinity of the second burner 20, a second ignition electrode 24 for igniting the second burner 20, and a second thermocouple 23 for detecting the combustion state of the second burner 20 (in the combustion state detection unit of the present invention). Corresponding).

  The controller 1 is an electronic circuit unit configured by a microcomputer 50 and the like which will be described later, and operates with electric power supplied from the battery 30. The gas stove is provided with a power switch 31 operated by a user, a first ignition switch 32 for the first burner 10, a second ignition switch 33 for the second burner 20, and an error lamp 34. When the user turns on the power switch 31, the power supply from the battery 30 to the controller 1 is started, and the controller 1 starts operating.

  When the operation signals (ignition operation signal and fire extinguishing operation signal) of the first ignition switch 32 and the second ignition switch 33 are input to the controller 1 and the ignition operation signal of the first ignition switch 32 is input, the controller 1 In the state where the original gas valve 6 and the first electromagnetic valve 11 are opened and the fuel gas is supplied to the first burner 10, a spark discharge is generated in the first ignition electrode 14 to ignite the first burner 10, The combustion operation of the first burner 10 is started. Further, when a fire extinguishing operation signal of the first ignition switch 32 is input during the combustion operation of the first burner 10, the controller 1 closes the original gas valve 6 and the first electromagnetic valve 11 to close the first burner. 10 combustion operation is terminated.

  Similarly, when an ignition operation signal of the second ignition switch 33 is input, the controller 1 opens the original gas valve 6 and the second electromagnetic valve 21 and supplies fuel gas to the second burner 20. Then, a spark discharge is generated in the second ignition electrode 24 to ignite the second burner 20, and the combustion operation of the second burner 20 is started. Further, when a fire extinguishing operation signal of the second ignition switch 33 is input during the combustion operation of the second burner 20, the controller 1 closes the original gas valve 6 and the second electromagnetic valve 21 and the second burner 20 is closed. The combustion operation of is terminated.

  Next, referring to FIG. 2, the controller 1 includes a microcomputer 50, a misfire monitoring circuit 90, interface circuits 80, 81, 82 of the first thermocouple 13 and the second thermocouple 23, and a drive coil of the original gas valve 6. FET 62 for switching between energization and de-energization of 6a, FET 65 for switching between energization and de-energization for drive coil 11a of first electromagnetic valve 11, and energization and de-energization for drive coil 21a of second electromagnetic valve 21 A switching FET 68 and the like are provided.

  The microcomputer 50 incorporates a CPU and a memory, and controls the operation of the gas stove by executing a gas stove control program stored in the memory. The microcomputer 50 includes output ports Po1 to Po5, input ports Pi1 to Pi3, and an AD (analog-digital conversion) input port Pad.

  The output ports Po3 to Po5 are connected to the gate terminals of the FETs 62, 65, and 68 through the inverting elements 73 to 75, respectively. By switching (logic high level) / Lo (logic low level), the FETs 62, 65, and 68 are switched between an energized state and a cut-off state. The reversing element 74 and the FET 65, and the reversing element 75 and the FET 68 constitute the solenoid valve drive circuit of the present invention.

  The source terminals of the FETs 62, 65, and 68 are connected to the V3 potential portion via a power supply FET 101 described later. Therefore, when the power supply FET 101 is ON (conducting state), by switching the output from the output ports Po3 to Po5 between Hi (V3 level) and Lo (GND level), the original gas valve 6 and the first electromagnetic valve 11 and the opening and closing of the second electromagnetic valve 21 can be controlled.

  The input ports Pi1 to Pi3 of the microcomputer 50 are connected to the drain terminals of the FETs 62, 65 and 68 through the inverting elements 76, 77 and 78, respectively. Here, when the drive coil 6a of the original gas valve 6 is energized, the Hi level voltage obtained by dividing the voltage between the V3 potential and the GND by the drive coil 6a, the resistor 61, the power feeding FET 101 and the FET 62 is an inverting element. 76 is input. On the other hand, when the drive coil 6a of the original gas valve 6 is not energized, the voltage at the drain terminal of the FET 62 is at the GND level, and the voltage input to the inverting element 76 is at the Lo level.

  Therefore, when the voltage input to the input port Pi1 is at the Lo level, the microcomputer 50 is in the closed state, and when the voltage input to the input port Pi1 is Hi-rel, the microcomputer 50 It is recognized that 6 is in a valve open state. Hereinafter, the voltage input to the inverting element 76 and the input port Pi1 is referred to as an original gas valve answer signal.

  Similarly, the microcomputer 50 detects the open / close state of the first electromagnetic valve 11 based on the voltage input to the input port Pi2, and detects the open / close state of the second electromagnetic valve 21 based on the voltage input to the input port Pi3. Hereinafter, the voltage input to the inverting element 77 and the input port Pi2 is referred to as a first electromagnetic valve answer signal, and the voltage input to the inverting element 78 and the input port Pi3 is referred to as a second electromagnetic valve answer signal. Moreover, the structure which detects the opening / closing state of the 1st solenoid valve 11 and the 2nd solenoid valve 21 in this way is equivalent to the opening / closing state detection part of this invention.

  The interface circuit 80 of the first thermocouple 13 outputs Lo when the detection signal of the first thermocouple 13 is at the misfire determination level, and outputs Hi when the detection signal of the first thermocouple 13 is not at the misfire determination level. Become a level.

  Similarly, the interface circuit 81 of the second thermocouple 23 outputs the Lo level when the detection signal of the second thermocouple 23 is at the misfire determination level, and when the detection signal of the second thermocouple 23 is not at the misfire determination level. The output becomes Hi level.

  The interface circuit 82 of the first thermocouple 13 and the second thermocouple 23 synthesizes and amplifies the detection signals of the first thermocouple 13 and the second thermocouple 23 and inputs them to the AD input port Pad of the microcomputer 50. The microcomputer 50 converts an analog signal input to the AD input port Pad into a digital value and reads it.

  When the microcomputer 50 is executing the gas stove control program, the microcomputer 50 outputs a charge pulse signal for charging the capacitor 120 of the misfire monitoring circuit 90 described later from the output port Po1. Further, the microcomputer 50 outputs a switching signal for increasing the charging current of the capacitor 120 from the output port Po2.

  The microcomputer 50 determines whether the first burner 10 has misfired from the detection signal input to the AD input port Pad during the combustion operation of the first burner 10. And when misfire of the 1st burner 10 is detected, the 1st solenoid valve 11 and the original gas valve 6 are closed, and supply of the fuel gas from the gas supply path 5 to the 1st burner 10 is stopped.

  Similarly, the microcomputer 50 determines whether or not the second burner 20 has misfired from the detection signal input to the AD input port Pad during the combustion operation of the second burner 20. And when misfire of the 2nd burner 20 is detected, the 2nd solenoid valve 21 and the original gas valve 6 are closed, and supply of the fuel gas from the gas supply path 5 to the 2nd burner 20 is stopped.

  Next, the misfire monitoring circuit 90 corresponds to the discharge timer composed of the capacitor 120 and the resistor 121, the charging circuit 140 that charges the capacitor 120, the discharge circuit 130 that discharges the capacitor 120, and the terminal voltage Vc of the capacitor 120. And an energization switching circuit 100 that switches between energization and deenergization of the FETs 62, 65, and 68 from the V3 potential portion.

  In the charging circuit 140, when a charge pulse signal is output from the output port Po1 of the microcomputer 50, the base current set by the resistors 143, 153, and 155 flows from the transistor 141 via the capacitor 154. Thereby, the transistor 141 is turned on (conductive state), and a charging current (corresponding to the second charging current of the present invention) flows from the V3.3 potential portion to the capacitor 120 via the resistor 142.

  On the other hand, when the output of the charge pulse signal from the output port Po1 is stopped due to a malfunction of the CPU of the microcomputer 50, etc., the transistor 141 is turned off (cut-off state), so the supply of the second charge current is stopped. In this case, the capacitor 154 is discharged by the discharge circuit 130 described later, and the original gas valve 6, the first electromagnetic valve 11, and the second electromagnetic valve 21 are closed by the operation of the energization switching circuit 100.

  When the charge pulse signal is output from the output port Po1 of the microcomputer 50 and the charge acceleration signal is output from the output port Po2, the base current set by the resistors 145, 150 and 152 is passed through the capacitor 151. The base current set by the resistors 147 and 149 flows from the transistor 146. As a result, both the transistors 144 and 146 are turned on, and a current flows from the V3.3 potential portion to the capacitor 120 via the resistor 148.

  In this case, the total current of the charging current supplied to the capacitor 120 via the transistor 141 and the charging current supplied to the capacitor 120 via the transistors 144 and 146 is the first charging current (> 2nd of the present invention). Charging current).

  Note that the configuration in which the charging current of the capacitor 120 is switched by the output of the charging acceleration signal from the output port Po2 of the microcomputer 50 corresponds to the charging current switching unit of the present invention.

  The discharge circuit 130 includes an AND element 132 to which the original gas valve answer signal, the first electromagnetic valve answer signal, and the misfire detection signal from the interface circuit 80 of the first thermocouple 13 are input, the original gas valve answer signal, An AND element 133 to which the solenoid valve answer signal and the misfire detection signal from the interface circuit 81 of the second thermocouple 23 are input, and a NOR element 131 to which the outputs of the AND elements 132 and 133 are input are provided.

  As for the output of the AND element 132, both the original gas valve answer signal and the first electromagnetic valve answer signal are at the Hi level (valve open state), and the misfire detection signal from the interface circuit 80 is at the Lo level (misfire state). At times (corresponding to the misfire determination state of the present invention), it becomes Hi level, and in other states, it becomes Lo level.

  Similarly, the output of the AND element 133 is that both the original gas valve answer signal and the open / close state detection signal of the second electromagnetic valve 21 are at the Hi level (valve open state) and the interface circuit 81 of the second thermocouple 23 When the misfire detection signal is at the Lo level (misfire state) (corresponding to the misfire determination state of the present invention), it is at the Hi level, and at other times it is at the Lo level.

  Therefore, when the first burner 10 misfires during the combustion operation of the first burner 10 (the original gas valve 6 and the first electromagnetic valve 11 are open) and during the combustion operation of the second burner 20 (the original gas valve 6 When the second burner 20 misfires when the second electromagnetic valve 21 is open), the output of the NOR element 131 becomes the Lo level.

  When the output of the NOR element 131 is at the Lo level, the charging current supplied from the charging circuit 140 flows to the NOR element 131 side, so the charging of the capacitor 120 is stopped. Then, since the electric charge charged in the capacitor 120 flows to the GND via the resistor 121, the capacitor 120 is discharged and the inter-terminal voltage Vc of the capacitor 120 gradually decreases. Note that energization from the capacitor 120 to the discharging circuit 130 and the charging circuit 140 is blocked by the diode 122.

  The energization switching circuit 100 includes a comparator 110 and a power feeding FET 101 that is driven according to the output voltage of the comparator 110. When the voltage at the −input terminal is higher than the input voltage at the + input terminal, the output of the comparator 110 is at the GND level, and when the voltage at the −input terminal is lower than the voltage at the + input terminal, the output is in a high impedance state. Become.

  When the output of the comparator 110 is at the GND level, the gate voltages of the FETs 104 and 108 are at the GND level, and the FETs 104 and 108 are turned off (blocked state). When the FET 108 is OFF, the voltage at the negative input terminal of the comparator 110 becomes the first threshold value Vth1 obtained by dividing the voltage between V3.3 and GND by the resistor 112 and the resistor 114. Further, when the FET 104 is OFF, the gate voltage of the power supply FET 101 is V3, and the power supply FET 101 is also OFF (cut-off state).

  On the other hand, when the output of the comparator 110 is in a high impedance state, the gate voltages of the FETs 104 and 108 become the V3.3 level, and the FETs 104 and 108 are turned on. When the FET 108 is ON, the voltage at the negative input terminal of the comparator 110 becomes the second threshold Vth2 (<Vth1) obtained by dividing the voltage between V3.3 and GND by the resistor 112 and the parallel resistance of the resistors 111 and 114. Further, when the FET 104 is ON, the gate voltage of the power supply FET 101 decreases to near the GND level, and the power supply FET 101 is turned on (conducting state).

  Next, operations of the microcomputer 50 and the misfire monitoring circuit 90 when the misfire of the first burner 10 occurs will be described according to the timing chart shown in FIG.

  FIG. 3 shows, in order from the top, the ON / OFF signal of the power switch 31, the charging pulse signal (indicated by a in FIG. 2) output from the output port Po1 of the microcomputer 50, and the output port Po2 of the microcomputer 50. Charge acceleration signal (indicated by b in FIG. 2), ON (ignition operation) / OFF (fire extinguishing operation) signal of the first ignition switch 32, driving of the first solenoid valve 11 output from the output port Po4 of the microcomputer 50 2 (indicated by “c” in FIG. 2), a misfire detection signal (indicated by “d” in FIG. 2) output from the interface circuit 80 of the first thermocouple 13, the terminal voltage Vc of the capacitor 120, and the output voltage of the comparator 110 (indicated by the figure). 2), ON / OFF of the power supply FET 101, and the first electromagnetic valve answer signal (indicated by g in FIG. 2) are shown by a common time axis t. The

  t1 is the time when the power switch 31 is turned on by the user, the power supply from the battery 30 to the controller 1 is started and the microcomputer 50 starts to operate, and the microcomputer 50 receives a charge pulse signal from the output port Po1. Is output.

  In addition, the microcomputer 50 outputs a charge acceleration signal from the output port Po2, and as a result, the transistors 141, 144, and 146 are turned on as described above, and the first charging current is supplied to the capacitor 120. 120 terminal voltage Vc increases rapidly.

  At t1, since the FET 108 is OFF (cut-off state), the voltage at the negative input terminal of the comparator becomes the first threshold value Vth1. Then, at t2 when the inter-terminal voltage Vc of the capacitor 120 becomes higher than the first threshold value Vth1, the output of the comparator 110 changes from the GND level to the high impedance state, and the voltage at the negative input terminal of the comparator 110 becomes the second threshold value Vth2. Switch to

  When the output of the comparator 110 is switched to the high impedance state at t2, the FET 104 is turned on and the power feeding FET 101 is turned on as described above.

  Further, since the first burner 10 is not ignited by the first ignition switch 32, the drive signal of the first electromagnetic valve 11 is Lo (closed control state), and the first burner 10 is in the fire extinguishing state. The output of the interface circuit 80 of the first thermocouple 13 is Hi level (misfire detection level).

  Tp of t1 to t3 rises to a voltage (corresponding to the misfire determination possible voltage of the present invention) required for ensuring the timer time equal to or greater than the misfire recognition time Tt described later, as the terminal voltage Vc of the capacitor 120 increases. It is an ignition prohibition period set to be more than time. In the ignition prohibition period Tp, the ignition process of the first burner 10 and the second burner 20 is prohibited.

  t4 is the time when the first ignition switch 32 is ignited by the user, and in response to the ignition operation, the microcomputer 50 performs the ignition process of the first burner 10 to perform the combustion operation of the first burner 10. Start. During the combustion operation of the first burner 10, the first electromagnetic valve 11 is maintained in the open state, and the first electromagnetic valve answer signal becomes Hi (opened state).

  Next, t5 is the time when the first burner 10 misfires. FIG. 3 shows a situation in which the misfire of the first burner 10 cannot be detected on the microcomputer 50 side due to a failure of the connection circuit from the first thermocouple 13 to the AD input port Pad of the microcomputer 50 (AD input). The input of the port Pad indicates the normal combustion range).

  When the output of the interface circuit 80 of the first solenoid valve 11 is switched from Hi (normal combustion state) to Lo (misfire state) at t4, as described above, the output of the NOR element 132 of the discharge circuit 130 is from Hi to Lo level. Switch to Then, the supply of the charging current to the capacitor 120 is stopped, the capacitor 120 starts discharging, and the terminal voltage Vc of the capacitor 120 gradually decreases.

  At t6 when the inter-terminal voltage Vc of the capacitor 120 becomes lower than the second threshold value Vth2, the output of the comparator 110 is switched from the high impedance state to the GND level, whereby the FET 104 is turned OFF and the power feeding FET 101 is turned OFF. When the power supply FET 101 is turned off, the energization of the drive coil 6a of the original gas valve 6 and the drive coil 11a of the first electromagnetic valve 11 is interrupted, and the original gas valve 6 and the first electromagnetic valve 11 are closed. The supply of fuel gas from the gas supply path 5 to the first burner 10 is stopped.

  In this case, since the gas source valve answer signal and the first electromagnetic valve answer signal become Lo (closed state), the output of the AND element 132 of the discharge circuit 130 switches to the Lo level. Then, the supply of the charging current from the discharge circuit 130 to the capacitor 120 is restarted, and the inter-terminal voltage Vc of the capacitor 120 gradually increases.

  Here, the microcomputer 50 outputs the charge acceleration signal from the output port Po2 only from t1 when the power supply from the battery 30 is started to t3 when the ignition inhibition period Tp elapses. Therefore, the charging current of the capacitor 120 after t6 is the second charging current, and the rise of the voltage Vc between the terminals of the capacitor 120 becomes more gradual than the ignition inhibition period Tp. As a result, the microcomputer 50 ensures the electromagnetic valve answer recognition period Ts set to be longer than the time necessary for recognizing the first electromagnetic valve answer signal.

  In the microcomputer 50, the answer signal of the first solenoid valve 11 becomes Lo (closed state) within the solenoid valve answer recognition period Ts until the terminal voltage Vc of the capacitor 120 exceeds the first threshold value Vth1 until t8. The drive signal for the original gas valve 6 output from the output port Po3 and the drive signal for the first electromagnetic valve 11 output from the output port Po4 are turned off.

  This prevents the original gas valve 6 and the first electromagnetic valve 11 from opening when the output of the comparator 110 is switched to the high impedance state at t8 and the power feeding FET 101 returns to the ON state. Further, the microcomputer 50 lights up the error lamp 34 (see FIG. 1) to notify the abnormality.

  In the present embodiment, the gas stove is shown as the combustion apparatus of the present invention. However, the present invention can be applied to any combustion apparatus that operates by the power supplied from the battery and determines burner misfire.

  In the present embodiment, the open / closed states of the original gas valve 6, the first electromagnetic valve 11, and the second electromagnetic valve 21 are detected based on whether or not the drive coil is energized, but the position of the valve element is recognized by a limit switch or the like. Thus, the open / close state of each valve may be detected.

  DESCRIPTION OF SYMBOLS 1 ... Controller, 5 ... Gas supply path, 6 ... Original gas valve, 10 ... 1st burner, 11 ... 1st solenoid valve, 12 ... 1st flow control apparatus, 13 ... 1st thermocouple, 14 ... 1st ignition electrode 20 ... second burner, 21 ... second solenoid valve, 22 ... second flow control device, 23 ... second thermocouple, 24 ... second ignition electrode, 31 ... power switch, 30 ... battery, 32 ... first ignition Switch, 33 ... second ignition switch, 50 ... microcomputer, 90 ... misfire monitoring circuit, 100 ... energization switching circuit, 130 ... discharge circuit, 140 ... charge circuit.

Claims (1)

A combustion apparatus that operates with electric power supplied from a battery and starts supplying electric power from the battery according to a user's operation,
With a burner,
An electromagnetic valve for opening and closing a fuel supply path connected to the burner;
A solenoid valve drive circuit that opens and closes the solenoid valve by switching between energization and de-energization of the drive coil of the solenoid valve;
A combustion state detector for detecting the combustion state of the burner;
An open / close state detection unit for detecting an open / close state of the solenoid valve;
When it is in a misfire determination state in which it is detected that the solenoid valve is open by the capacitor and the open / close state detection unit, and the burner is detected to be extinguished by the combustion state detection unit A discharging circuit for discharging the capacitor; a charging circuit for charging the capacitor when not in the misfire determination state; and when the voltage across the capacitor is shifted from a state lower than a first threshold to a high state, Switching from a non-energized state where the energization to the drive coil of the solenoid valve is impossible to an energizable state where the energization is possible, and in the energized state, the voltage across the terminals of the capacitor is lower than the second threshold value, which is lower than the first threshold value. A misfire monitoring circuit having an energization switching circuit for switching from the energized state to the unenergized state when
The charging current supplied from the charging circuit to the capacitor is defined as a first charging current when power supply from the battery is started, and the capacitor is charged by the first charging current between the terminals of the capacitor. A charging current switching unit that sets a charging current of the capacitor to a second charging current smaller than the first charging current after the voltage is equal to or higher than the misfire determination possible voltage set to the first threshold or more;
After the power supply from the battery is started and the voltage between the terminals of the capacitor becomes equal to or higher than the misfire determination voltage, the solenoid valve is opened by the solenoid valve driving circuit and the burner combustion operation is started. When the burner misfire is detected by the combustion state detector during the combustion operation, and when the solenoid valve is closed by the open / close state detector during the combustion operation, the electromagnetic And a microcomputer for stopping energization of the drive coil of the solenoid valve by the valve drive circuit.