JP2018031572A - Combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve safety and to reduce processing load of each of microcomputers in combustion equipment including the plurality of microcomputers in a control portion.SOLUTION: Combustion equipment includes control valves PSV, SV necessary for starting combustion in a combustion portion, and a control portion outputting first and second control signals to drive the control valves PSV, SV, and the control portion includes first and second microcomputers 1, 2. A first control signal is output by the first microcomputer 1, a second control signal is output by the second microcomputer, and operations of the control valves PSV, SV necessary for starting the combustion in the combustion portion, are not implemented unless the first microcomputer outputs the first control signal, and the second microcomputer outputs the second control signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a combustion device such as a gas fan heater or an instantaneous water heater.

  In the following Patent Document 1, the applicant of the present application describes a main microcomputer that performs general control of the combustion device and performs a cutoff operation that shuts off the fuel supply, and a fuel supply cutoff operation that is independent of the main control device. When the main microcomputer and the sub microcomputer receive a signal for knowing the operation state of the combustion device, the main microcomputer and the sub microcomputer receive a signal indicating a predetermined stop signal. Disclosed is a combustion control device configured to perform an emergency shut-off operation.

  In such a conventional combustion control device, the main microcomputer performs general control of the combustion device, the combustion operation is executed, the sub microcomputer confirms whether the combustion operation is performed correctly, and if an abnormality is detected The sub-microcomputer can forcibly stop the fuel supply.

Japanese Patent No. 4877604

  However, the control necessary for performing the combustion operation is performed only by the main microcomputer, and if an abnormality occurs in the main microcomputer, such as when the main microcomputer runs away, the combustion operation is performed by the abnormal control by the main microcomputer that has runaway. Even if the sub-microcomputer detects an abnormality, it is after the start of the combustion operation.

  In addition, since the main microcomputer performs all the control necessary to perform the combustion operation, it is necessary to adopt a high-performance microcomputer with a high processing speed as the main microcomputer, and there is a processing load at the start of combustion. There is a case where there is no room for other control to be performed at high.

  Therefore, there is room for improvement in order to further improve safety and function.

  Accordingly, an object of the present invention is to further improve the safety and reduce the processing load of each microcomputer in a combustion device including a plurality of microcomputers in a control unit.

  In order to achieve the above object, the present invention takes the following technical means.

  That is, the present invention includes one or a plurality of control target devices necessary for starting combustion in the combustion unit, and a control unit that outputs first and second control signals for driving the control target devices. And the control unit is a combustion device including first and second microcomputers (microcontrollers or microcomputers), and the first control signal is output by the first microcomputer, and the second control The signal is output by the second microcomputer. If the first microcomputer outputs the first control signal and the second microcomputer does not output the second control signal, combustion in the combustion section is started. It is configured such that at least one of the one or a plurality of control target devices necessary for the operation does not operate (Claim 1).

  According to the combustion device of the present invention, either one of the first and second microcomputers distributes drive control (combustion start sequence) of the control target device necessary for starting combustion in the combustion section to one of them. It is possible to avoid concentrating the processing load on the microcomputer, and to allow a margin for the processing load, so that a cheaper microcomputer can be used, or other control processing can be performed simultaneously at the start of combustion Is possible. Furthermore, since both microcomputers do not output the above control signal, combustion in the combustion section does not start, so combustion may start if either microcomputer runs out of control and outputs an abnormal signal. Can be reduced.

  In the combustion device of the present invention, the control target device includes first and second control valves capable of closing a fuel supply path to the combustion unit, and the first control valve is opened by a first control signal. When the first control signal is not outputted and closed, the second control valve is opened by the second control signal. When the second control signal is not outputted, the second control valve is closed. Claim 2). According to this, if the first and second control signals are not normally output, fuel is not supplied to the combustion section, and not only the combustion operation is not started, but also fuel leakage can be avoided, The safety can be further improved.

  The first and second control valves can be provided in series with the fuel supply path. Each electromagnetic valve may be a flow control valve such as an electromagnetic open / close valve or a proportional valve with a closing function that can be fully closed. Preferably, the first microcomputer monitors the operation of the second control valve when the second microcomputer outputs the second control signal, and performs predetermined abnormality processing when an abnormality is detected. it can. Furthermore, the second microcomputer can be configured to monitor the operation of the first control valve when the first microcomputer outputs the first control signal and to perform a predetermined abnormality process when an abnormality is detected. As described above, the first and second microcomputers monitor the operation of the control target device as the control signal output result of the other microcomputer, thereby further improving the safety.

  In the combustion apparatus of the present invention, the control target apparatus includes at least one control valve capable of closing a fuel supply path to the combustion unit, and the control valve receives the first and second control signals. By being output, the control valve drive power supply is conducted, and when at least one of the first and second control signals is not output, the power supply may be cut off from the power supply. ). Even in such a configuration, if the first and second control signals are not normally output, the control valve is shut off from the power source, the control valve does not open, and the combustion operation does not start. Leakage can also be avoided.

  ADVANTAGE OF THE INVENTION According to this invention, in the combustion equipment provided with a some microcomputer in a control part, while improving further safety | security, the processing load of each microcomputer can be reduced.

It is a schematic circuit diagram of the control board of the gas fan heater (combustion equipment) concerning a 1st embodiment of the present invention. It is a schematic circuit diagram of the control board of the gas fan heater (combustion equipment) concerning a 2nd embodiment of the present invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a control board (control unit) of a gas fan heater as a combustion device according to the first embodiment of the present invention. The basic configuration of the gas fan heater is the same as that disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-121372, and a fuel gas is supplied to the gas burner (combustion unit) disposed in the combustion space in the casing and the gas burner. A refueling pressure line proportional valve PSV (first control valve) and an original gas solenoid valve SV (second control valve) provided in series in the middle of the fuel supply line, A combustion fan for taking combustion air into the gas burner and discharging the combustion gas, an igniter IG for igniting the gas burner, and a control board for controlling various operations are provided. The proportional valve PSV, the electromagnetic valve SV, the fan motor M that rotates the combustion fan, and the igniter IG are control target devices required to start combustion in the gas burner, and their operations are controlled by the control board. It is comprised so that.

  As shown in FIG. 1, the control board includes a main microcomputer 1 (first microcomputer) and a sub-microcomputer 2 (second microcomputer) as a control center. These microcomputers 1 and 2 can communicate with each other. In addition to being connected to each other, a reset signal can be transmitted to the reset port. The control board includes a proportional valve drive circuit 3, an electromagnetic valve drive circuit 4, a fan drive circuit 5, and an igniter drive circuit 6.

  The proportional valve drive circuit 3 generates a drive current having a magnitude corresponding to the proportional valve control output voltage (first control signal) output from the analog signal output port of the main microcomputer 1 by an electromagnetic coil (not shown) of the proportional valve PSV. ). That is, the proportional valve drive circuit 3 includes an operational amplifier OP, a drive transistor Q1, and a resistance element R1. The electromagnetic coil of the proportional valve PSV, the drive transistor Q1, and the resistance element R1 are connected in series between the power supply line (15V) and the ground. The drive transistor Q1 is composed of an npn transistor, and its emitter output voltage is negatively fed back to the inverting input terminal (− terminal) of the operational amplifier OP. The proportional valve control output voltage from the main microcomputer 1 is input to the non-inverting input terminal (+ terminal) of the operational amplifier OP.

  Therefore, the magnitude of the drive current of the proportional valve PSV is controlled by the virtual short circuit of the operational amplifier OP so that the emitter output voltage of the drive transistor Q1 becomes equal to the proportional valve control output voltage. When the proportional valve control output voltage is 0 V, the drive current of the proportional valve PSV is also 0. At this time, the proportional valve PSV is configured to be fully closed by an urging means such as a built-in spring. A capacitor C1 made of an electrolytic capacitor is connected in parallel to the electromagnetic coil of the proportional valve PSV.

  The emitter output voltage of the drive transistor Q1 is configured to be input to the proportional valve monitoring input ports of the main microcomputer 1 and the sub microcomputer 2.

  The solenoid valve drive circuit 4 is configured to open and close the solenoid valve SV based on a solenoid valve control output signal (second control signal) output from the digital signal output port of the sub-microcomputer 2. That is, the electromagnetic valve drive circuit 4 is configured by connecting an electromagnetic coil (not shown) of the electromagnetic valve SV and a switching element Q2 such as an FET in series between the power supply line and the ground. A diode D1 for short-circuiting the back electromotive force is connected in parallel to the electromagnetic coil of the valve SV.

  Therefore, when a High signal is output from the sub-microcomputer 2 to the switching element Q2 as an electromagnetic valve control output signal for opening the electromagnetic valve SV, the switching element Q2 is turned on and a drive current flows through the electromagnetic valve SV. The solenoid valve SV is opened. On the other hand, when the Low signal is output from the sub-microcomputer 2 to the switching element Q2, the switching element Q2 becomes non-conductive and the drive current of the solenoid valve SV becomes zero, and the energizing of a spring or the like built in the solenoid valve SV is performed. The electromagnetic valve SV is closed by the means.

  Further, the negative side voltage of the electromagnetic valve SV is configured to be input to the respective electromagnetic valve monitoring input ports of the main microcomputer 1 and the sub microcomputer 2.

  The fan drive circuit 5 can be constituted by a conventionally known appropriate motor driver, and based on the fan drive command signal and the fan rotational speed command signal output from the main microcomputer 1, the actual rotational speed of the fan is commanded by the fan rotational speed command signal. A drive current is supplied to the fan motor M so as to achieve the set rotational speed.

  The igniter drive circuit 6 is configured to ignite the igniter IG based on an igniter control output signal output from the digital signal output port of the main microcomputer 1. That is, the igniter drive circuit 6 includes a normally open contact type relay RL that switches whether or not to supply AC power to the igniter IG, and a switching element Q3 such as an npn transistor connected in series to the electromagnetic coil of the relay RL. The relay RL and the switching element Q3 are connected between the power supply line and the ground. A diode D2 for short-circuiting the back electromotive force is connected in parallel to the electromagnetic coil of the relay RL.

  Therefore, when a High signal is output from the main microcomputer 1 to the switching element Q3 as an igniter control output signal for igniting the igniter IG, the switching element Q3 is turned on and a drive current flows through the electromagnetic coil of the relay RL. As a result, the contact is closed and the igniter IG is ignited.

  An operation board 7 is communicably connected to the main microcomputer 1. The operation board 7 has a display unit 71 for displaying room temperature and other appropriate displays, and for turning on / off the operation. The operation switch 72 and a setting operation switch 73 for performing an appropriate setting operation such as temperature setting are provided. When the operation switch 72 is turned on, the main microcomputer 1 starts the heating operation control to start combustion in the gas burner. When the operation switch 72 is turned off, the main microcomputer 1 ends the heating operation control and performs predetermined end processing such as combustion stop. Do.

  Next, a combustion start sequence in the control board will be described.

  When the main microcomputer 1 recognizes that the operation switch 72 of the operation board 7 has been turned on, a predetermined signal (first confirmation signal) is transmitted to the sub-microcomputer 2 through inter-microcomputer communication.

  When the sub microcomputer 2 receives the first confirmation signal from the main microcomputer 1, the sub microcomputer 2 returns a predetermined reply signal to the main microcomputer 1.

  When there is a reply signal from the sub-microcomputer 2, the main microcomputer 1 performs a failure check on the proportional valve drive circuit 3 and the electromagnetic valve drive circuit 4. This failure check method may be any appropriate method to check whether the proportional valve monitoring voltage and the solenoid valve monitoring voltage are within the normal range when the proportional valve PSV and the solenoid valve SV are not driven and controlled. It is also possible to check whether the proportional valve monitoring voltage and the solenoid valve monitoring voltage are within the normal range when the proportional valve PSV and the solenoid valve SV are alternately driven and controlled on a trial basis. It may be.

  If there is no abnormality in the failure check, the main microcomputer 1 outputs the fan drive command signal and the fan rotation speed command signal to the fan drive circuit 5 to drive the fan motor M to rotate, thereby detecting the rotation speed. For example, an electromagnetic valve opening command for opening the electromagnetic valve SV is transmitted to the sub-microcomputer 2 through communication between the microcomputers.

  When the sub-microcomputer 2 receives the electromagnetic valve opening command signal from the main microcomputer 1, the sub-microcomputer 2 opens the electromagnetic valve SV by outputting a high signal (electromagnetic valve control output signal) to the switching element Q2 of the electromagnetic valve drive circuit 4. .

  When the main microcomputer 1 transmits an electromagnetic valve opening command to the sub-microcomputer 2 and confirms that the electromagnetic valve SV has been opened by monitoring the electromagnetic valve monitoring voltage, the main microcomputer 1 sends a high signal (igniter) to the switching element Q3 of the igniter drive circuit 6. Igniter IG is ignited by outputting a control output signal), and then proportional valve control output voltage is output to proportional valve drive circuit 4 to set proportional valve PSV to a predetermined opening, whereby combustion operation in the gas burner Starts.

  On the other hand, if the main microcomputer 1 cannot confirm that the solenoid valve SV has been opened by monitoring the solenoid valve monitoring voltage after a predetermined time has elapsed after transmitting the solenoid valve opening command to the sub microcomputer 2, It is determined that the microcomputer 2 is abnormal. Further, if the sub-microcomputer 2 cannot confirm that the proportional valve PSV has been opened by monitoring the proportional valve monitoring voltage even after a predetermined time has elapsed after opening the solenoid valve SV, an error has occurred in the main microcomputer 1. Judge that there is.

  The main microcomputer 1 and the sub microcomputer 2 detect an abnormality in the proportional valve drive circuit 3 or the electromagnetic valve drive circuit 4 during the above-described sequence or after the start of the combustion operation, or determine that the other microcomputer is abnormal. In this case, the microcomputer is reset by outputting a reset signal to the reset port of the microcomputer in the abnormal state, and when the main microcomputer 1 is normal, the proportional valve PSV is closed and the sub microcomputer 2 is normal. In this case, the solenoid valve SV is closed.

  As described above, in the gas fan heater of the two microcomputer specification of the main microcomputer 1 and the sub microcomputer 2, the control output of the proportional valve PSV with the closing function is assigned to the main microcomputer 1, and the control output of the electromagnetic valve SV is assigned to the sub microcomputer 2. Thus, when one of the microcomputers is not in a normal state, combustion can be stopped and the release of raw gas can be prevented, thereby further improving the safety.

  FIG. 2 is a circuit diagram of a control board according to the second embodiment of the present invention. Components similar to those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and different configurations and effects are provided. explain. In FIG. 2, the igniter driving circuit and the fan driving circuit are omitted for the sake of simplicity.

  In the control board of the second embodiment, the control output to the proportional valve drive circuit 3 and the electromagnetic valve drive circuit 4 are both output from the main microcomputer 1. In this embodiment, the proportional valve PSV and the solenoid valve SV are connected to the power supply line (15V) via the switching circuit 8. When the power cutoff output of the main microcomputer 1 is a High signal (first control signal) and the power cutoff output of the sub-microcomputer 2 is a Low signal (second control signal), the switching circuit 8 is a proportional valve. Conduction is performed so as to supply power for driving the PSV and the solenoid valve SV. On the other hand, if the power cutoff output of the main microcomputer 1 is a Low signal (third control signal) or the power cutoff output of the sub-microcomputer 2 is a High signal (fourth control signal), the switching circuit 8 is The shut-off state is established, and power is not supplied to the proportional valve PSV and the solenoid valve SV.

  The negative voltage of the switching circuit 8 (the positive voltage of the proportional valve PSV and the solenoid valve SV) is monitored by the power supply monitoring circuit 9, and if the voltage is equal to or higher than a predetermined voltage (for example, 13V or higher), the switching circuit 8 A signal indicating that the circuit is in a conductive state (for example, a low signal) is output to the main microcomputer 1, and if the voltage is less than a predetermined voltage, a signal indicating that the switching circuit 8 is in a cutoff state (for example, a high signal) is output It is configured to

  The main microcomputer 1 is configured to perform a circuit check of the switching circuit 8 at the start of combustion (at the time of ignition).

  That is, when the operation switch 72 of the operation board 7 is turned on, first, the main microcomputer 1 confirms that the signal from the power supply monitoring circuit 9 is a high signal, that is, the switching circuit 8 is in the cutoff state.

  Next, the main microcomputer 1 sets the power shut-off output as a high signal, and at this stage also confirms that the signal from the power monitoring circuit 9 is still a high signal.

  Next, the main microcomputer 1 transmits information indicating that the operation switch 72 has been turned on to the sub-microcomputer 2 through inter-microcomputer communication, and sets the power cutoff output of the main microcomputer 1 to a Low signal. When the sub-microcomputer 2 receives information from the main microcomputer 1 that the operation switch 72 has been turned on, the sub-microcomputer 2 sets the power cutoff output of the sub-microcomputer 2 as a Low signal. The main microcomputer 1 transmits the above information to the sub-microcomputer 2 and then monitors the signal from the power supply monitoring circuit 9 for a predetermined time (about several tens of milliseconds), and the signal is maintained as a high signal. Make sure.

  If no abnormality is detected in the above confirmation operation, the main microcomputer 1 drives the solenoid valve SV, fan motor, proportional valve PSV, and igniter IG sequentially in accordance with a predetermined combustion start sequence to ignite and shift to the combustion state. To do. On the other hand, if an abnormality is confirmed, the combustion start sequence is not executed, the power cutoff output for switching the switching circuit 8 off is performed, and an error is displayed on the display unit 71 of the operation board 7. When it is determined that an abnormality has occurred in one of the microcomputers, appropriate abnormality processing can be performed such as resetting by transmitting a reset signal from the other microcomputer to the reset port of one of the microcomputers.

  During combustion, the main microcomputer 1 and the sub-microcomputer 2 monitor the proportional valve monitoring voltage and the electromagnetic valve monitoring voltage, respectively. If the mutual monitoring data is different or communication between microcomputers cannot be performed normally, the switching circuit 8 Each of the microcomputers 1 and 2 is configured to output a power cut-off so as to be in a cut-off state.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the present invention can be applied to combustion equipment such as an instantaneous gas water heater and a gas stove. In the first embodiment, the proportional valve control signal has been described as the first control signal, and the electromagnetic valve control signal has been described as the second control signal. However, the first or second control signal may be an igniter control signal or a fan. It may be a drive command signal or the like. Further, the first and second control signals may each drive two switching circuits provided in series in one control target device.

1 First microcomputer (main microcomputer)
2 Second microcomputer (sub microcomputer)
3 Proportional valve drive circuit 4 Solenoid valve drive circuit 5 Fan drive circuit 6 Igniter drive circuit 7 Operation board 8 Switching circuit 9 Power supply monitoring circuit PSV Proportional valve SV Solenoid valve

Claims (3)

One or a plurality of control target devices necessary for starting combustion in the combustion unit, and a control unit that outputs first and second control signals for driving the control target device, the control unit includes: In the combustion equipment comprising the first and second microcomputers,
The first control signal is output by a first microcomputer, the second control signal is output by a second microcomputer, the first microcomputer outputs a first control signal, and If the second microcomputer does not output the second control signal, at least one of the one or more control target devices necessary for starting combustion in the combustion section is configured not to operate. Burning equipment.   2. The combustion device according to claim 1, wherein the control target device includes first and second control valves capable of closing a fuel supply path to the combustion unit, wherein the first control valve is a first control signal. When the first control signal is not output, the second control valve is opened when the second control valve is opened, and when the second control signal is not output, the second control valve is closed. Characteristic combustion equipment.   The combustion apparatus according to claim 1, further comprising at least one control valve capable of closing a fuel supply path to the combustion unit as the control target apparatus, wherein the control valve receives first and second control signals. Combustion configured to be connected to a power supply for driving the control valve by being output, and to be cut off from the power supply when at least one of the first and second control signals is not output machine.

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