CN-114992873-B - Gas water heater and flame detection method and device thereof

CN114992873BCN 114992873 BCN114992873 BCN 114992873BCN-114992873-B

Abstract

The invention discloses a gas water heater and a flame detection method and a device thereof, wherein the flame detection method comprises the following steps of receiving a detection value of a flame detection parameter at the current moment; the method comprises the steps of acquiring the flame state of the last moment, determining a threshold value required for judging the flame detection result of the current moment according to the flame state of the last moment, and determining the flame detection result of the current moment according to the relation between the detection value of the flame detection parameter of the current moment and the threshold value. When the flame state at the current moment is determined, the control threshold value required for judging the flame state at the current moment is determined through the flame state at the last moment, so that the accuracy of flame detection is improved.

Inventors

LIU NING
ZHANG WEI
XUE RUIHUA

Assignees

重庆海尔热水器有限公司
青岛经济技术开发区海尔热水器有限公司
海尔智家股份有限公司

Dates

Publication Date: 20260508
Application Date: 20210604

Claims (5)

1. A flame detection method of a gas water heater is characterized by comprising the following steps: Receiving a detection value of a flame detection parameter at the current moment, wherein the flame detection parameter comprises an AD value of flame; acquiring a flame state of the last moment, determining a threshold value required for judging a flame detection result of the current moment according to the flame state of the last moment, and comprising the following steps: Acquiring a flame state at the previous moment, if the flame state at the previous moment is flameless, determining a first threshold K1 as a threshold required for judging a flame detection result, and if the flame state at the previous moment is flameless, determining a second threshold K2 as a threshold required for judging the flame detection result, wherein the second threshold K2 is greater than the first threshold K1; determining a flame detection result at the current moment according to the relation between the detection value of the flame detection parameter at the current moment and the threshold value, wherein the method comprises the following steps: If the flame state at the previous moment is flameless, outputting a signal with flame when the detection value of the flame detection parameter at the current moment is smaller than the first threshold K1, and outputting a flameless signal when the detection value of the flame detection parameter at the current moment is larger than or equal to the first threshold K1; and if the flame state at the previous moment is flame, outputting a signal with flame when the detection value of the flame detection parameter at the current moment is smaller than the second threshold K2, and outputting a signal without flame when the detection value of the flame detection parameter at the current moment is larger than or equal to the second threshold K2.
2. The flame detection method of a gas water heater as recited in claim 1, wherein: the step of acquiring the flame state at the last moment comprises the following steps: if the MCU port voltage at the last moment in the flame detection circuit is low level, the flame state at the last moment is flameless; If the MCU port voltage at the last moment in the flame detection circuit is high level, the flame state at the last moment is flame; In the flame detection circuit, one end of an alternating current high-voltage source AC is connected with reference ground, the other end of the alternating current high-voltage source AC is connected with one end of a capacitor C1 through a resistor R2, the other end of the capacitor C1 is connected with a resistor R5, the other end of the resistor R5 is connected with a flame sensing probe, the resistor R6 is connected with reference ground and shell ground, one end of a resistor R3 is connected with a junction A of the capacitor C1 and the resistor R5, the other end of the resistor R3 is connected with a cathode of a diode D2, an anode of the diode D2 is grounded, the diode D1 and the resistor R1 are connected in parallel, two ends of the diode D1 are respectively connected with a junction of a power VCC and the diode D2, one end of a resistor R4 is connected with a junction of the resistor R3 and the diode D2, the other end of the resistor R4 is connected with one end of the capacitor C2, the other end of the capacitor C2 is grounded, and the junction of the resistor R4 and the capacitor C2 is connected with the MCU.
3. A flame detection device of a gas water heater is characterized by being used for implementing the flame detection method as claimed in claim 1 or 2, and comprising The first detection module is used for detecting the detection value of the flame detection parameter at the current moment; The second detection module is used for detecting the flame state at the last moment; the determining module is used for determining a threshold value required by judging a flame detection result at the current moment according to the flame state at the last moment detected by the second detecting module; the logic judging module is used for determining a flame detection result at the current moment according to the relation between the detection value of the flame detection parameter at the current moment and the threshold value, and comprises the following steps: A first judging unit, configured to determine a flame detection result at a current time when the flame state at the previous time is flameless, if the flame state at the previous time is flameless, output a signal with flame when the detection value of the flame detection parameter at the current time is less than a first threshold K1, and output a signal without flame when the detection value of the flame detection parameter at the current time is greater than or equal to the first threshold K1; and the second judging unit is used for determining a flame detection result at the current moment when the flame state at the previous moment is flame, outputting a flame signal when the detection value of the flame detection parameter at the current moment is smaller than a second threshold K2 and outputting a flame-free signal when the detection value of the flame detection parameter at the current moment is larger than or equal to the second threshold K2 if the flame state at the previous moment is flame.
4. The flame detection device of a gas water heater as recited in claim 3, further comprising a flame detection circuit; In the flame detection circuit, one end of an alternating current high-voltage source AC is connected with reference ground, the other end of the alternating current high-voltage source AC is connected with one end of a capacitor C1 through a resistor R2, the other end of the capacitor C1 is connected with a resistor R5, the other end of the resistor R5 is connected with a flame sensing probe, the resistor R6 is connected with reference ground and shell ground, one end of a resistor R3 is connected with a junction A of the capacitor C1 and the resistor R5, the other end of the resistor R3 is connected with a cathode of a diode D2, an anode of the diode D2 is grounded, the diode D1 and the resistor R1 are connected in parallel, two ends of the diode D1 are respectively connected with a junction of a power VCC and the diode D2, one end of a resistor R4 is connected with a junction of the resistor R3 and the diode D2, the other end of the resistor R4 is connected with one end of the capacitor C2, the other end of the capacitor C2 is grounded, and the junction of the resistor R4 and the capacitor C2 is connected with a single chip microcomputer MCU.
5. A gas water heater characterized in that a flame detection method as claimed in claim 1 or 2 is employed or a flame detection device as claimed in claim 3 or 4 is included.

Description

Gas water heater and flame detection method and device thereof Technical Field The invention belongs to the technical field of gas water heaters, and particularly relates to a gas water heater and a flame detection method and device thereof. Background The flame detection in the use process of the gas water heater is not only closely related to safety, but also closely related to the control logic of the gas water heater. A simple and reliable flame detection circuit is a link which is necessary for the intelligent gas water heater. The utility model patent with publication number CN 201742316U discloses a flame induction circuit of a gas water heater, which comprises a flame sensing module, a comparator module and an oscillation boosting module, wherein a flame sensing needle is electrically connected with the flame sensing module and transmits signals to the flame sensing module, the flame sensing module transmits signals to the comparator module, the comparator module transmits signals to a main control circuit, the flame sensing circuit is integrated on an independent sensing circuit board and is electrically connected with the main control circuit on a main control substrate of the gas water heater through an interface, the comparator module and the oscillation boosting module acquire a direct current power supply from the main control circuit of the main control substrate through the interface respectively, and the oscillation boosting module boosts the acquired direct current power supply and oscillates to form alternating current power to supply the flame sensing module. The above document describes a solution for detecting a flame using a comparator, which is costly. The patent application of publication number CN 107991713A discloses a flame induction system for gas quick water heater and hanging stove, including flame induction needle, flame induction oscillating circuit, power supply circuit and microprocessor, this system still includes flame induction circuit and AD acquisition circuit, power supply circuit provides the power for the system, flame induction oscillating circuit's output carries alternating voltage to flame induction circuit's energy input, flame induction circuit passes through the flame induction needle with flame information conversion into flame signal, AD acquisition circuit's signal input part is connected with flame induction circuit's signal output part, and AD acquisition circuit's output is connected with microprocessor's signal input part, and microprocessor carries out signal recognition. The above document describes a flame AD value detecting and judging combustion state circuit, but the limit of existence of flame is not clear, the detected flame tolerance is small, and flame misjudgment is easily caused when the combustion state is switched. The present invention has been made in view of this. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a flame detection method of a gas water heater, wherein when the flame state at the current moment is determined, a comparison threshold value required for judging the flame state at the current moment is determined through the flame state at the last moment, so that the accuracy of flame detection is improved. The invention further aims to provide a flame detection device of the gas water heater, when determining the flame state at the current moment, the determining module determines a comparison threshold value required for judging the flame state at the current moment according to the flame state at the last moment, so that the accuracy of flame detection is improved. Another object of the present invention is to provide a gas water heater employing the flame detection method as described above or comprising the flame detection device as described above. In order to solve the technical problems, the invention adopts the basic conception of the technical scheme that: A flame detection method of a gas water heater comprises the following steps: Receiving a detection value of a flame detection parameter at the current moment; Acquiring a flame state at the previous moment, and determining a threshold value required for judging a flame detection result at the current moment according to the flame state at the previous moment; and determining a flame detection result at the current moment according to the relation between the detection value of the flame detection parameter at the current moment and the threshold value. Further, the obtaining the flame state at the previous moment, determining a threshold value required for judging the flame detection result at the current moment according to the flame state at the previous moment, includes: Acquiring a flame state at the previous moment, if the flame state at the previous moment is flameless, determining a first threshold K1 as a threshold required for judging a flame detection result, and if the flame state at the previous mome