Gas water heater and control method thereof

Abstract

The application provides a gas water heater and a control method thereof, wherein the control method comprises: obtaining a power-on event of the gas water heater; obtaining oxygen content of air at an air inlet of the gas water heater to obtain inlet air oxygen content; correcting a preset combustion curve of the gas water heater according to the inlet air oxygen content to obtain a corrected curve, wherein the combustion curve is used to define a corresponding relationship between a gas valve opening degree and a fan rotating speed of the gas water heater; and adjusting the gas valve and the fan of the gas water heater according to the corrected curve during water heating of the gas water heater. The scheme of the application automatically adapts to differences of different working environments, and avoids combustion instability caused by air differences.

Description

TECHNICAL FIELD

[0001] The present application relates to water heaters, in particular to a gas water heater and a control method thereof. BACKGROUND

[0002] The gas water heater is accepted by more and more users due to its small size, constant temperature, high power and saving advantages. When the gas water heater works, the opening degree of the gas valve is adjusted according to the required heat to obtain hot water at the required temperature. The fan speed of the water heater matches the opening degree of the gas valve during the combustion process, so as to achieve a stable air-fuel ratio and ensure stable combustion.

[0003] With the growth of the application range and supply of natural gas, the users of the gas water heater increase year by year, and the users are more widely distributed. Due to the wide use of the gas water heater, the gas composition is different in different regions, the altitude is different in different regions, and the oxygen content in the air is also different. However, the control scheme of the existing gas water heater is mostly set before leaving the factory, and it is not targeted to adjust the specific use environment, so when the gas water heater is used in the area with large difference in altitude and standard environment, the combustion condition is abnormal, which affects the normal use. SUMMARY

[0004] An object of the present application is to provide a gas water heater and a control method thereof which can ensure normal work in different regions.

[0005] A further object of the present application is to maintain stable and efficient combustion heating in different altitude working environments.

[0006] Another further object of the present application is to adapt the gas water heater to different weather environments and maintain stable combustion under different exhaust conditions.

[0007] In particular, the present application provides a control method of a gas water heater, comprising:

[0008] obtaining a power-on event of the gas water heater;

[0009] obtaining the oxygen content of the air at the air inlet of the gas water heater to obtain the inlet oxygen content;

[0010] correcting a preset combustion curve of the gas water heater according to the inlet oxygen content to obtain a corrected curve, wherein the combustion curve is used to define the corresponding relationship between the opening degree of the gas valve and the fan speed of the gas water heater;

[0011] adjusting the gas valve and the fan of the gas water heater according to the corrected curve during the supply of hot water by the gas water heater.

[0012] Optionally, the step of correcting the preset combustion curve of the gas water heater according to the oxygen content of the incoming air comprises:

[0013] calculating a fan speed compensation coefficient according to the oxygen content of the incoming air;

[0014] performing compensation calculation on the fan speed in the preset combustion curve according to the fan speed compensation coefficient;

[0015] resetting the preset combustion curve using the compensated fan speed value to obtain a corrected curve.

[0016] Optionally, the step of calculating a fan speed compensation coefficient according to the oxygen content of the incoming air comprises:

[0017] calculating a relative value of the oxygen content of the incoming air compared to the standard oxygen content;

[0018] determining the fan speed compensation coefficient according to the relative value.

[0019] Optionally, the step of determining the fan speed compensation coefficient according to the relative value comprises:

[0020] obtaining a pre-stored parameter correspondence table of oxygen content relative value and altitude;

[0021] determining the altitude corresponding to the relative value according to the parameter correspondence table, and matching to obtain the fan speed compensation coefficient of the altitude.

[0022] Optionally, the step of adjusting the gas valve and the fan of the gas water heater according to the corrected curve comprises:

[0023] obtaining a heating demand parameter of the gas water heater;

[0024] determining a target opening degree of the gas valve according to the heating demand parameter;

[0025] querying a fan target speed corresponding to the target opening degree from the corrected curve;

[0026] adjusting the gas valve according to the target opening degree, and adjusting the fan according to the fan target speed.

[0027] Optionally, the step of adjusting the fan according to the fan target speed further comprises:

[0028] obtaining the oxygen content of the flue gas discharged by the gas water heater to obtain a flue gas oxygen content;

[0029] obtaining a corresponding flue gas oxygen content expected range in a stable combustion state of the gas water heater;

[0030] judging whether the flue gas oxygen content exceeds the flue gas oxygen content expected range;

[0031] If yes, further adjust the rotation speed of the fan until the oxygen content of the flue gas reaches the expected range of the oxygen content of the flue gas or the rotation speed of the fan reaches the limit.

[0032] Optionally, in the case that the oxygen content of the flue gas does not exceed the expected range of the oxygen content of the flue gas, the rotation speed of the fan is maintained unchanged.

[0033] Optionally, after the rotation speed of the fan reaches the limit, further comprising:

[0034] calculating the difference between the oxygen content of the incoming air and the oxygen content of the flue gas;

[0035] judging whether the difference between the oxygen content of the incoming air and the oxygen content of the flue gas exceeds the normal range;

[0036] If yes, output a fault alarm signal and control the gas water heater to shut down.

[0037] According to another aspect of the present application, there is also provided a gas water heater, comprising:

[0038] a fan for providing air required by the gas water heater for combustion;

[0039] a gas valve for adjusting the supply amount of gas of the gas water heater; and

[0040] a first oxygen sensor for detecting the oxygen content of air at the air inlet of the gas water heater; and

[0041] a controller comprising a memory, a processor and a machine executable program stored on the memory and running on the processor, and the processor implements the control method of any of the above gas water heaters when executing the machine executable program.

[0042] Optionally, the above gas water heater further comprises a second oxygen sensor for detecting the oxygen content of flue gas discharged by the gas water heater, and the first oxygen sensor is arranged at the air outlet of the fan and the second oxygen sensor is arranged in the fume hood of the gas water heater.

[0043] The gas water heater and the control method thereof of the present application, after the gas water heater is powered on, for example, after initial installation and use or after the power is turned on again, the oxygen content of the incoming air is obtained to determine the oxygen content in the air participating in combustion, and the combustion curve preset for the gas water heater is corrected using the oxygen content of the incoming air, so that the combustion curve matches the oxygen content in the current working state. During the process of heating water for combustion, the gas valve and the fan are adjusted according to the corrected combustion curve, so that the gas and air participating in combustion reach the most suitable ratio. The gas water heater using the control method can adapt to the difference in oxygen content at different altitudes, avoiding the problem of unstable combustion caused by air difference.

[0044] Further, the gas water heater and the control method thereof can obtain the oxygen content of the exhaust flue gas, i.e., the flue gas oxygen content, during the supply of hot water by the gas water heater, and further adjust the air volume of the fan according to the flue gas oxygen content, so that the flue gas oxygen content is maintained within an expected range of flue gas oxygen content that ensures stable and reliable combustion. In this way, the gas water heater can be adjusted in time in the case of excessive external wind pressure and blocked flue gas exhaust, and the abnormal combustion condition can be avoided, thereby improving the reliability of the gas water heater.

[0045] Further, the gas water heater and the control method thereof can obtain the oxygen content of the exhaust flue gas, i.e., the flue gas oxygen content, during the supply of hot water by the gas water heater, and further adjust the air volume of the fan according to the flue gas oxygen content, so that the flue gas oxygen content is maintained within an expected range of flue gas oxygen content that ensures stable and reliable combustion. In this way, the gas water heater can be adjusted in time in the case of excessive external wind pressure and blocked flue gas exhaust, and the abnormal combustion condition can be avoided, thereby improving the reliability of the gas water heater.

[0046] The above and other objects, advantages and features of the present application will become more apparent from the following detailed description of some embodiments thereof, when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0047] Some embodiments of the present application will now be described in detail with reference to the accompanying drawings, which are provided by way of example and are not limiting of the present application. Like references denote like elements or portions in the accompanying drawings. It should be noted that the drawings are not necessarily drawn to scale. In the drawings:

[0048] Figure 1 is a schematic diagram of a gas water heater according to an embodiment of the present application;

[0049] Figure 2 is a schematic block diagram of control components in a gas water heater according to an embodiment of the present application;

[0050] Figure 3 is a schematic diagram of a control method of a gas water heater according to an embodiment of the present application;

[0051] Figure 4 is a flowchart of correcting a combustion curve in a control method of a gas water heater according to an embodiment of the present application; and

[0052] Figure 5 is a flowchart of adjusting according to a corrected curve in a control method of a gas water heater according to an embodiment of the present application. DETAILED DESCRIPTION

[0053] Figure 1 is a schematic diagram of a gas water heater according to an embodiment of the present application. Figure 2 is a schematic block diagram of control components in a gas water heater according to an embodiment of the present application. The gas water heater 10 can generally include a cold water pipe 113, a flow meter 112, a heat exchanger 114, a hot water pipe 115, a gas pipe 121, a gas valve 122, a gas distribution pipe 123, a burner 124, a fume hood 125, an exhaust pipe 126, a first oxygen sensor 131, a second oxygen sensor 132, and a fan 133. The end of the cold water pipe 113 is connected to an external water source through a water inlet 111 to introduce cold water. The end of the hot water pipe 115 is connected to a water using device through a water outlet 116.

[0054] The gas water heater 10 uses gas as fuel and heats water by burning. The working principle of the gas water heater 10 is as follows. After the water valve is opened, cold water enters the cold water pipe 113 through the water inlet 111. When the flow meter 112 detects that the water flow reaches the ignition flow, the gas valve 122 is opened, and gas is supplied from the gas pipe 121 into the gas water heater. The gas distribution pipe 123 distributes the gas to different areas of the burner 124 to ensure uniform combustion of the burner 124. At the same time, the fan 133 is turned on to supply fresh air to the combustion area to ensure sufficient combustion of the gas. The heat generated by the combustion heats the water flowing through the heat exchanger 114 to the set temperature, and finally the hot water is supplied from the water outlet through the hot water pipe 115. The fume hood 125 is located at the top of the combustion chamber to collect the flue gas generated after combustion. The exhaust pipe 126 is connected to the fume hood 125 to exhaust the flue gas outside. During the above process, the combustion process can be controlled by adjusting the opening of the gas valve 122 and the speed of the fan 133 to ensure stable combustion and meet the requirements of constant temperature heating.

[0055] In this embodiment, the gas valve 122 is a proportional valve, and its opening can be adjusted to regulate the gas supply of the gas water heater 10. The fan 133 uses a speed-regulated motor to provide the air required for combustion of the gas water heater 10, and the air supply can be changed by adjusting the speed. The gas water heater 10 maintains the air-fuel ratio (i.e., the ratio of air and gas) within a reasonable range by adjusting the ratio of gas and air, further realizing safe and stable operation.

[0056] In contrast, the control method of the prior art gas water heater generally determines the combustion load according to the water flow size, the water inlet temperature, and the water outlet temperature, adjusts the opening degree of the gas valve 122 accordingly, and supplies the burner with the gas corresponding to the combustion load. Meanwhile, the fan speed is adjusted according to a preset combustion curve (the corresponding relationship between the opening degree of the gas valve and the fan speed). The combustion curve is configured according to the test and calculation of the manufacturer. However, in the actual working environment, the altitude of different geographical environments may cause differences in air composition, and the preset combustion curve may not guarantee that the combustion condition is in the best state. In addition, the weather environment may also affect the wind pressure of the exhaust environment. In some cases, the air pressure in the smoke hood increases, which may cause the exhaust air volume of the fan to decrease under the same speed condition, which also affects the combustion stability. In severe cases, it may cause the exhaust of flue gas to be blocked.

[0057] The gas water heater 10 of the present embodiment is additionally provided with a first oxygen sensor 131 and a second oxygen sensor 132. The first oxygen sensor 131 is used to detect the oxygen content of the air at the air inlet of the gas water heater 10, and can be arranged at the air outlet of the fan 133. The second oxygen sensor 132 is used to detect the oxygen content of the flue gas discharged by the gas water heater 10, and can be arranged in the smoke hood 125 of the gas water heater 10.

[0058] The gas water heater 10 of the present embodiment is further provided with a controller 210, which includes a memory 230, a processor 220, and a machine executable program 231 stored in the memory 230 and running on the processor 220, and the processor 220 implements the control method of the gas water heater of the present embodiment when executing the machine executable program 231.

[0059] It should be understood that the parts of the present embodiment can be realized by hardware, software, firmware, or a combination thereof. In the method of the present embodiment, a plurality of steps or methods can be realized by software or firmware stored in the memory 230 and executed by the appropriate processor 220.

[0060] The processor 220 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0061] Memory 230 can include random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), and any suitable combination thereof.

[0062] Machine executable program 231 can be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages.

[0063] Controller 210 connects first oxygen sensor 131, second oxygen sensor 132, flow meter 112 and other measuring devices through input interface, acquires working state of gas water heater 10, forms control command through data processing and judgment, and sends control signal to fan 132, gas valve 122 and other execution components through output interface, to complete the control method of the embodiment.

[0064] Figure 3 is a schematic diagram of a control method of a gas water heater according to an embodiment of the application. The control method of the gas water heater comprises:

[0065] Step S302, acquiring the power-on event of the gas water heater. The power-on event can be the first start event after the installation of the gas water heater, or the restart event after the power-off of the gas water heater.

[0066] Step S304, acquiring the oxygen content of the air at the air inlet of the gas water heater to obtain the inlet oxygen content. The oxygen content in the air is generally affected by factors such as altitude, especially in plateau areas, the oxygen content will decrease seriously. However, in the combustion process, the air composition participating in combustion is oxygen. Therefore, the combustion state of the gas water heater in different working areas also changes accordingly.

[0067] Step S306, correcting the preset combustion curve of the gas water heater according to the inlet oxygen content to obtain a corrected curve, wherein the combustion curve is used to define the corresponding relationship between the gas valve opening degree and the fan speed of the gas water heater.

[0068] The combustion curve is a recommended corresponding relationship that can make the gas water heater achieve stable combustion through testing and calculation. The preset combustion curve of the gas water heater is generally formulated and verified in a standard working environment. In the case of differences in the working environment, the above-mentioned preset combustion curve deviates from the actual combustion required conditions, for example, in the working environment of high altitude, the problem of insufficient oxygen supply leading to combustion efficiency decline may occur.

[0069] The combustion curve of the gas water heater is corrected by using the oxygen content of the incoming air, so that the combustion curve can conform to the current operating environment, the fan and the gas valve can match the operation, and stable and efficient combustion can be ensured.

[0070] In step S308, the gas valve and the fan of the gas water heater are adjusted according to the corrected curve during the supply of hot water by the gas water heater.

[0071] The control method of the gas water heater can adapt to the difference in oxygen content at different altitudes, and avoid the problem of unstable combustion caused by air difference.

[0072] The correction process of step S306 can be: calculating a fan speed compensation coefficient according to the oxygen content of the incoming air; compensating and calculating the fan speed in the pre-set combustion curve according to the fan speed compensation coefficient; resetting the pre-set combustion curve using the fan speed value after the compensation calculation to obtain the corrected curve. The fan speed compensation coefficient can increase the oxygen supply to the combustion chamber by increasing the fan speed, that is, in the case of a decrease in the oxygen content of the incoming air, the oxygen supply is increased by fan speed compensation, so as to adapt to the combustion requirement.

[0073] The step of calculating the fan speed compensation coefficient according to the oxygen content of the incoming air includes: calculating the relative value of the oxygen content of the incoming air compared with the standard oxygen content; determining the fan speed compensation coefficient according to the relative value. The calculation method of the relative value can be: taking the oxygen content of the standard environment as the standard value, and calculating the relative value according to the ratio of the detected oxygen content of the incoming air to the standard value.

[0074] In some embodiments, the oxygen content can be calculated by the air density. In the standard environment, the relative value is 1, and the oxygen content of the incoming air decreases by 10%, so the relative value of the oxygen content of the incoming air compared with the standard oxygen content changes to 90%.

[0075] The step of determining the fan speed compensation coefficient according to the relative value can include: obtaining a parameter correspondence table of the relative value of the oxygen content and the altitude; determining the altitude corresponding to the relative value according to the parameter correspondence table, and matching to obtain the fan speed compensation coefficient of the altitude.

[0076] The parameter correspondence table of the relative value of the oxygen content and the altitude can be pre-stored in the gas water heater, or can be obtained from the network service device by the network request of the gas water heater. The parameter correspondence table of the relative value of the oxygen content and the altitude can be summarized according to the data obtained by testing, calculating and verifying in different altitudes. The recorded data can include any one or more of the following: oxygen content relative value, altitude data, compensation coefficient of fan speed at different altitudes.

[0077] The fan speed compensation value can be obtained by multiplying the fan speed at each point in the preset combustion curve by a fan speed compensation coefficient or by using other calculation methods. The fan speed compensation value can ensure that the amount of oxygen supplied by the fan to the combustion chamber matches the amount of fuel gas supplied, achieving stable combustion.

[0078] The step S308 of adjusting the gas valve and the fan of the gas water heater according to the correction curve can include: obtaining a heating demand parameter of the gas water heater; determining a target opening degree of the gas valve according to the heating demand parameter; querying a target rotating speed of the fan corresponding to the target opening degree from the correction curve; adjusting the gas valve according to the target opening degree, and adjusting the fan according to the target rotating speed of the fan.

[0079] The heating demand parameter can include the inlet water temperature, the outlet water set temperature, the water flow, etc. These heating demand parameters correspond to the required heating load, and the heating load is determined by the amount of fuel gas supplied and the opening degree of the gas valve. Therefore, the target opening degree of the gas valve determined according to the heating demand parameter directly reflects the amount of fuel gas supplied to meet the hot water supply condition. The finally obtained target opening degree and target rotating speed of the fan can meet the water heating demand and also meet the stable combustion condition.

[0080] After step S308, the control method of the embodiment can further include: obtaining an oxygen content of flue gas discharged by the gas water heater to obtain a flue gas oxygen content; obtaining a flue gas oxygen content expected range corresponding to a stable combustion state of the gas water heater; determining whether the flue gas oxygen content exceeds the flue gas oxygen content expected range; if the flue gas oxygen content exceeds the flue gas oxygen content expected range, further adjusting the rotating speed of the fan until the flue gas oxygen content reaches the flue gas oxygen content expected range or the rotating speed of the fan reaches a limit.

[0081] The flue gas oxygen content expected range is obtained according to the test results and / or calculated theoretical values of the stable combustion state of the gas water heater, and it can reflect the composition after oxygen and fuel gas are combusted. By determining whether the flue gas oxygen content exceeds the flue gas oxygen content expected range, the combustion result of the gas water heater can be determined to further control the fan.

[0082] When the flue gas oxygen content is lower than the lower limit of the flue gas oxygen content expected range, the oxygen supply amount can be increased by increasing the rotating speed of the fan, so as to increase the flue gas oxygen content; when the flue gas oxygen content is higher than the upper limit of the flue gas oxygen content expected range, the oxygen supply amount can be reduced by reducing the rotating speed of the fan, so as to reduce the flue gas oxygen content.

[0083] Under normal circumstances, the above-mentioned gas valve and fan of the gas water heater adjusted according to the modified curve can ensure the normal operation of the gas water heater, and the flue gas oxygen content is within the expected range of the flue gas oxygen content. However, if the internal components work abnormally or the environment changes, for example, the exhaust air pressure increases, resulting in a decrease in the air supply at the same fan speed, the flue gas oxygen content may exceed the expected range of the flue gas oxygen content. Therefore, the control method of the embodiment can determine the combustion state by using the flue gas oxygen content, and adjust the fan accordingly, so as to further realize adaptive control of the gas water heater and improve the reliability and stability of the gas water heater.

[0084] Under the condition that the flue gas oxygen content does not exceed the expected range of the flue gas oxygen content, the speed of the fan is maintained unchanged, so that the gas water heater can operate stably.

[0085] If the speed of the fan is adjusted to the maximum or minimum, that is, the speed of the fan reaches the limit, the control method of the embodiment can further calculate the difference between the inlet air oxygen content and the flue gas oxygen content, judge whether the difference between the inlet air oxygen content and the flue gas oxygen content exceeds the normal range, and if so, output a fault alarm signal and control the gas water heater to shut down.

[0086] The above-mentioned adjustment of the speed of the fan to the limit value still causes the difference between the inlet air oxygen content and the flue gas oxygen content to be abnormal, which indicates that the gas water heater has an abnormal state that cannot be adjusted. At this time, through safety protection, more serious faults can be avoided.

[0087] Through the above introduction, it can be clear that the gas water heater and the control method thereof of the embodiment can adapt to different altitudes, gas types and air pressure changes based on the detection of oxygen content, adjust the combustion through adaptive control, realize stable combustion, and detect, judge and adjust quickly and efficiently.

[0088] The inlet air oxygen content can correct the combustion curve at different altitudes and realize stable air-fuel ratio combustion. The comparison of the flue gas oxygen content with the expected range of the flue gas oxygen content can quickly adjust the speed of the fan when the external air pressure changes, so as to ensure stable air-fuel ratio combustion.

[0089] In addition, by means of the difference between the inlet air oxygen content and the flue gas oxygen content, the combustion oxygen consumption can be judged, and then the change of the gas source can be judged, so as to adjust the speed of the fan to match the air-fuel gas and realize stable combustion. When the difference between the inlet air oxygen content and the flue gas oxygen content is abnormal, the fan or the gas valve can be quickly determined to be abnormal, and then safety protection and control of the whole machine are realized.

[0090] Figure 4 It is a flowchart for correcting the combustion curve in the control method of the gas water heater according to an embodiment of the present application. The control method of the gas water heater of the embodiment includes the following steps:

[0091] Step S402, power on the gas water heater;

[0092] Step S404, obtain the oxygen content of the incoming air;

[0093] Step S406, obtain the pre-stored parameter correspondence table of the relative value of the oxygen content and the altitude;

[0094] Step S408, determine the altitude corresponding to the relative value according to the parameter correspondence table, and match to obtain the fan speed compensation coefficient of the altitude;

[0095] Step S410, the fan speed compensation coefficient compensates the fan speed in the pre-set combustion curve;

[0096] Step S412, reset the combustion curve.

[0097] Figure 5 is a flow chart of the gas water heater control method according to the modified curve. The gas water heater control method according to the modified curve adjusts the fan and the gas valve, and includes the following steps:

[0098] Step S502, the water flow of the gas water heater exceeds the ignition threshold; that is, the water flow of the gas water heater exceeds the set water flow threshold for starting combustion. The setting of the ignition threshold is generally to make the water and gas linkage to avoid empty combustion.

[0099] Step S504, obtain the heating parameters such as water temperature and set temperature;

[0100] Step S506, obtain the reset combustion curve;

[0101] Step S508, adjust the gas valve and the fan according to the gas valve target opening and the fan target speed in the reset combustion curve;

[0102] Step S510, real-time detect the flue gas oxygen content and the incoming air oxygen content;

[0103] Step S512, judge whether the flue gas oxygen content exceeds the expected range of the flue gas oxygen content;

[0104] Step S514, in the case that the flue gas oxygen content does not exceed the expected range of the flue gas oxygen content, maintain the fan speed unchanged;

[0105] Step S516, in the case that the flue gas oxygen content exceeds the expected range of the flue gas oxygen content, the fan speed is adjusted accordingly; in the case that the flue gas oxygen content is lower than the lower limit of the expected range of the flue gas oxygen content, the oxygen supply amount can be increased by increasing the fan speed, so as to increase the flue gas oxygen content; in the case that the flue gas oxygen content is higher than the upper limit of the expected range of the flue gas oxygen content, the oxygen supply amount can be reduced by reducing the fan speed, so as to reduce the flue gas oxygen content.

[0106] Step S518, it is judged whether the fan speed reaches the limit;

[0107] Step S520, it is judged whether the difference between the intake air oxygen content and the flue gas oxygen content exceeds the normal range; that is, it is judged whether the oxygen consumption exceeds the normal range;

[0108] Step S522, in the case that the fan speed reaches the limit and the difference between the intake air oxygen content and the flue gas oxygen content exceeds the normal range, a fault alarm signal is outputted, and the gas water heater is controlled to shut down.

[0109] The flowchart provided by the embodiment is not intended to indicate that the operations of the method are performed in any specific order, or that all the operations of the method are included in all cases. In addition, the method can include additional operations. Within the scope of the technical idea provided by the method of the embodiment, additional changes can be made to the above method.

[0110] Through actual verification of the method of the embodiment, the gas water heater can meet the conditions for stable combustion in different states, maintain the optimal air-fuel ratio, and solve the technical problem of poor environmental adaptability existing in the prior art.

[0111] At this point, those skilled in the art should recognize that, although the plurality of exemplary embodiments of the present application have been shown and described in detail herein, many other variations or modifications can be determined or deduced directly from the disclosure of the present application in accordance with the principles of the present application without departing from the spirit and scope of the present application. Therefore, the scope of the present application should be understood and recognized as covering all these other variations or modifications.

Claims

1. A control method of a gas water heater, comprising: obtaining a power-on event of the gas water heater; obtaining an oxygen content of air at an air inlet of the gas water heater, to obtain an inlet oxygen content; correcting a preset combustion curve of the gas water heater according to the inlet oxygen content, to obtain a corrected curve, wherein the preset combustion curve is used to define a corresponding relationship between a gas valve opening degree and a fan speed of the gas water heater; adjusting the gas valve and the fan of the gas water heater according to the corrected curve during a hot water supply of the gas water heater, and the step of adjusting the gas valve and the fan of the gas water heater according to the corrected curve comprises: obtaining a heating demand parameter of the gas water heater; determining a target opening degree of the gas valve according to the heating demand parameter; inquiring a target fan speed corresponding to the target opening degree from the corrected curve; adjusting the gas valve according to the target opening degree and adjusting the fan according to the target fan speed; obtaining an oxygen content of flue gas discharged by the gas water heater, to obtain a flue gas oxygen content; obtaining a corresponding expected range of the flue gas oxygen content in a stable combustion state of the gas water heater; judging whether the flue gas oxygen content exceeds the expected range of the flue gas oxygen content; if yes, further adjusting the speed of the fan until the flue gas oxygen content reaches the expected range of the flue gas oxygen content, and if the speed of the fan reaches a limit, the method further comprises: calculating a difference between the inlet oxygen content and the flue gas oxygen content; judging whether the difference between the inlet oxygen content and the flue gas oxygen content exceeds a normal range; if yes, outputting a fault alarm signal and controlling the gas water heater to shut down. 2.The control method of the gas water heater according to claim 1, wherein the step of correcting the preset combustion curve of the gas water heater according to the inlet oxygen content comprises: calculating a fan speed compensation coefficient according to the inlet oxygen content; performing compensation calculation on the fan speed in the preset combustion curve according to the fan speed compensation coefficient; and resetting the preset combustion curve using the fan speed value after the compensation calculation to obtain the corrected curve. 3.The control method of the gas water heater according to claim 2, wherein the step of calculating the fan speed compensation coefficient according to the inlet oxygen content comprises: calculating a relative value of the inlet oxygen content compared to a standard oxygen content; and determining the fan speed compensation coefficient according to the relative value. 4.The control method of the gas water heater according to claim 3, wherein the step of determining the fan speed compensation coefficient according to the relative value comprises: obtaining a parameter correspondence table of pre-stored oxygen content relative values and altitudes; and determining an altitude corresponding to the relative value according to the parameter correspondence table, and matching to obtain the fan speed compensation coefficient of the altitude. 5.The control method of the gas water heater according to claim 1, wherein in a case where the flue gas oxygen content does not exceed the expected range of the flue gas oxygen content, the speed of the fan is maintained unchanged. 6.A gas water heater, comprising: a fan configured to provide air required for combustion of the gas water heater; a gas valve for adjusting a gas supply amount of the gas water heater; and a first oxygen sensor for detecting an oxygen content of air at an air inlet of the gas water heater; and a controller comprising a memory, a processor, and a machine executable program stored on the memory and running on the processor, and the processor implements the control method of the gas water heater according to any one of claims 1 to 5 when executing the machine executable program.

7. The gas water heater according to claim 6, further comprising: a second oxygen sensor for detecting an oxygen content of flue gas discharged by the gas water heater, wherein the first oxygen sensor is arranged at an air outlet of the fan, and the second oxygen sensor is arranged in a flue hood of the gas water heater.

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