Fireplace control method and system thereof

Abstract

The present application relates to the field of solid fuel stove technology, and discloses a fireplace control method and system, which comprises the following steps: collecting indoor temperature and exhaust temperature, starting a power adjustment program when the temperature difference decreases to a threshold value, turning off the screw feeder and releasing the proportional linkage control relationship between the screw feeder and the air blower; obtaining the supply accumulation and the exhaust temperature change slope to calculate the residual heat of the hearth; determining the air volume compensation gain according to the calculation result and adjusting the air blower speed, and using the enhanced oxygen supply condition to make the inventory fuel burn out quickly. The present application constructs an asynchronous dissipation mechanism based on the exhaust temperature gradient, effectively offsets the physical heat inertia generated by the solid fuel combustion, eliminates the room temperature overshoot phenomenon caused by material lag, accurately controls the oxygen supply amount to ensure the full combustion of the inventory material, suppresses the generation of carbon deposition from the physical level, and improves the safety and reliability of the equipment operation.

Description

Technical Field

[0001] This invention relates to a fireplace control method and system, belonging to the field of solid fuel stove technology. Background Technology

[0002] Currently, household solid fuel stoves typically use controllers to adjust the frequency of the feeding motor and the speed of the combustion fan to match the heat output with the indoor heat demand. Due to the thermal inertia of combustion and the physical inability to be instantly shut off, there is a response lag between the control command and the actual heat output. When the indoor temperature reaches the set threshold and the system stops physical feeding, the fuel stored in the furnace continues to release heat energy into the external space.

[0003] Traditional control methods often follow a linear logic of synchronous adjustment of fuel and air. When the system reduces its operating power to pursue temperature control accuracy, the proportional reduction in the amount of fuel supplied and the amount of combustion air will lead to a deterioration of the combustion microenvironment, making it difficult to meet the specific oxygenation requirements of solid fuels during the burnout stage. The limitations of the control logic restrict the accuracy of temperature control and combustion stability. For example, Chinese invention patent application CN116097037A discloses an electronic adjustment device for a bottom-burning fireplace. It evaluates the combustion state by detecting the rate of temperature change over time and adjusts the valve opening. This technology is a feedback adjustment based on the comparison of the actual target temperature. The closed-loop logic is based on the surface evolution of temperature characteristics. Under actual complex working conditions, the system fails to deeply define the physical mass and residual energy of the material accumulated in the furnace. The adjustment action lags behind the release of fuel thermal inertia and lacks quantitative characterization of the heat generation of existing fuel. This makes it difficult for the system to accurately offset the oxygen supply and physical heat potential at critical nodes where the temperature difference approaches zero. It cannot eliminate temperature overshoot and is prone to smoldering and carbon buildup at the moment of power switching due to the imbalance of the air-fuel ratio.

[0004] Therefore, the technical problem to be solved by this invention is how to achieve quantitative characterization and asynchronous controlled dissipation of residual thermal potential energy based on the physical mechanism of solid fuel combustion, and solve the problems of temperature control deviation caused by thermal inertia and carbon deposition caused by incomplete combustion. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A fireplace control method, comprising the following steps:

[0006] Step 101: Obtain the indoor temperature and exhaust temperature in real time, and retrieve the preset set temperature;

[0007] Step 102: Calculate the temperature difference between the indoor temperature and the set temperature, and determine that the system enters the power regulation stage when the temperature difference decreases to the preset temperature threshold.

[0008] Step 103: In response to the triggering of the power regulation stage, the screw feeder is turned off and the proportional linkage control relationship between the screw feeder and the blower is released to stop the supply of fuel to the furnace.

[0009] Step 104: Obtain the cumulative feed amount within the preset sliding time window before shutting off the screw feeder, and calculate the slope of the exhaust temperature change within the preset sliding time window to measure the residual heat generation inside the furnace.

[0010] Step 105: Determine the air volume compensation gain for offsetting thermal inertia based on the residual heat generation, and increase the speed of the blower according to the air volume compensation gain, so as to burn off the remaining fuel in the furnace by using the increased oxygen supply.

[0011] Step 106: Monitor the real-time rate of decrease of exhaust temperature and control the speed of the blower to decrease synchronously with the real-time rate of decrease until the exhaust temperature drops to the preset shutdown temperature point.

[0012] Preferably, step 104 further includes: step 1041, retrieving the operating duty cycle of the screw feeder within a preset sliding time window, and calculating the cumulative feed amount based on the operating duty cycle; step 1042, converting the cumulative feed amount and the change slope into residual heat generation using a preset physical mapping relationship, wherein the residual heat generation is positively correlated with both the cumulative feed amount and the change slope.

[0013] Preferably, the residual calorific value is calculated using the following formula: ,in, This is the quantified value of residual heat. To accumulate the amount of material fed, This is the change in exhaust temperature. To preset the duration of the sliding time window, as well as These are the preset physical mapping coefficients for solid fuels.

[0014] Preferably, before step 101, an ignition control step is included: step 401, activating the ignition rod and turning on the screw feeder and blower; step 402, reading the exhaust temperature, and when the exhaust temperature reaches the preset ignition success threshold, confirming successful ignition and controlling the system to switch to step 101.

[0015] Preferably, it also includes a negative pressure monitoring safety protection step: step 501, using a negative pressure sensor to collect the negative pressure value inside the furnace in real time; step 502, determining whether the negative pressure value deviates from the preset safe negative pressure range; step 503, if the negative pressure value deviates from the preset safe negative pressure range, then shutting off the screw feeder and ignition rod, and increasing the speed of the blower to the preset exhaust speed.

[0016] Preferably, in step 105, the duration of the blower speed increase is 30s to 60s.

[0017] Preferably, step 106 further includes: step 1061, calculating the second derivative of the exhaust temperature in real time; step 1062, correcting the speed reduction slope of the blower based on the second derivative, so as to reduce the formation of carbon deposits inside the furnace.

[0018] Preferably, the method also includes a remote data synchronization step: step 801, synchronizing the indoor temperature and exhaust temperature to the cloud server via the wireless communication module; step 802, receiving the control command issued by the remote terminal, and updating the set temperature according to the control command.

[0019] Preferably, the preset temperature threshold is 1.5℃, and the method also includes a flashback warning step: Step 1001, monitor the pipeline temperature of the screw feeder; Step 1002, if the pipeline temperature exceeds the preset flashback warning threshold, shut down the screw feeder and output a warning signal.

[0020] A fireplace control system includes a sensor array, a feeding mechanism, a variable frequency fan, an ignition rod, and a main controller.

[0021] The sensor group includes an indoor temperature sensor, an exhaust temperature sensor, a furnace negative pressure sensor, and a feed temperature sensor. The sensor group is connected to the main controller.

[0022] Feeding mechanisms, including screw feeders, are used for controlled conveying or stopping the supply of solid pellet fuel;

[0023] Variable frequency fans are used to control the amount of combustion air inside the furnace.

[0024] The central controller is electrically connected to the sensor group, feeding mechanism, variable frequency fan, and ignition rod. Specifically, the central controller determines the trigger state of the power adjustment phase based on the temperature difference between the indoor temperature and the set temperature. Upon entering the power adjustment phase, it drives the feeding mechanism to stop feeding and disengages the proportional linkage control relationship between the feeding mechanism and the variable frequency fan. The central controller also calculates the residual heat generation based on the duty cycle of the screw feeder and the slope of the exhaust temperature change, and adjusts the output frequency of the variable frequency fan based on the airflow compensation gain determined by the residual heat generation. Furthermore, the central controller monitors the real-time decrease slope of the exhaust temperature and drives the variable frequency fan speed to decrease synchronously with the real-time decrease slope.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. In the fireplace control method, by decoupling the physical fuel delivery command and the combustion air volume adjustment command, an asynchronous dissipation mechanism based on the exhaust temperature change gradient is constructed. This effectively counteracts the inherent physical thermal inertia in the solid fuel combustion process. Since solid fuel has the characteristic of exothermic properties that cannot be turned off instantaneously, this invention actively interrupts the physical feed and reverses to increase the combustion air volume when the indoor temperature enters the critical range. It uses an artificially constructed forced oxidation environment to quickly dissipate the heat energy stored in the furnace. This mechanism breaks the linear logic of the proportional increase and decrease of the feed and air volume in the traditional control scheme, solves the problem of room temperature overshoot caused by the nonlinear disconnect between command execution and heat output response, and enables the heating output curve to achieve dynamic physical matching with the actual heat load demand of the space.

[0027] 2. By utilizing the physical relationship between the transient decay slope of exhaust temperature and the cumulative feed volume, the invention achieves precise quantitative characterization of residual heat potential inside the furnace, eliminating the accumulation of pollutants caused by smoldering of solid fuels. At the critical point when the ambient temperature approaches the target value, the invention forcibly burns off the existing carbon-based materials in the grate by strengthening the oxygen supply, avoiding the low-oxygen smoldering state caused by the decrease in conventional power. The precise control of this physical process not only reduces the condensation and adhesion of tar and carbides inside the flue pipe, reducing the fire hazard caused by carbon buildup in the flue, but also improves the underlying safety and long-term operational stability of the equipment under complex working conditions by logically reshaping the combustion microenvironment.

[0028] 3. By transforming the waste heat dissipation process during the combustion stage into a controlled source of indoor constant temperature compensation, the energy utilization method is structurally improved. Through the synchronous anchoring of the convection circulation speed and the heat energy attenuation trajectory of the exhaust node, the system can slowly pump the clean waste heat released after complete combustion in the furnace into the indoor space in a controlled convection form, completing the final physical compensation to the target temperature. This solution changes the traditional fireplace model that relies on a single heat source input, and incorporates the residual heat energy that was originally uncontrollable loss into the closed-loop control system. Without changing the physical hardware configuration, it expands the refined energy efficiency performance of the equipment in the low temperature difference adjustment stage by relying on the deep integration of control logic and combustion mechanism. Attached Figure Description

[0029] Figure 1 This is a flowchart of the asynchronous heat dissipation control process for the fireplace, which is used for the quantitative calculation of residual heat according to the present invention.

[0030] Figure 2 This is a system logic architecture diagram of the present invention that balances thermal inertia countermeasures and carbon buildup suppression.

[0031] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] A fireplace control method includes the following steps:

[0034] Step 101: Obtain the indoor temperature and exhaust temperature in real time, and retrieve the preset set temperature;

[0035] Step 102: Calculate the temperature difference between the indoor temperature and the set temperature, and determine that the system enters the power regulation stage when the temperature difference decreases to the preset temperature threshold.

[0036] Step 103: In response to the triggering of the power regulation stage, the screw feeder is turned off and the proportional linkage control relationship between the screw feeder and the blower is released to stop the supply of fuel to the furnace.

[0037] Step 104: Obtain the cumulative feed amount within the preset sliding time window before shutting off the screw feeder, and calculate the slope of the exhaust temperature change within the preset sliding time window to measure the residual heat generation inside the furnace.

[0038] Step 105: Determine the air volume compensation gain for offsetting thermal inertia based on the residual heat generation, and increase the speed of the blower according to the air volume compensation gain, so as to burn off the remaining fuel in the furnace by using the increased oxygen supply.

[0039] Step 106: Monitor the real-time rate of decrease of exhaust temperature and control the speed of the blower to decrease synchronously with the real-time rate of decrease until the exhaust temperature drops to the preset shutdown temperature point.

[0040] Preferably, step 104 further includes: step 1041, retrieving the operating duty cycle of the screw feeder within a preset sliding time window, and calculating the cumulative feed amount based on the operating duty cycle; step 1042, converting the cumulative feed amount and the change slope into residual heat generation using a preset physical mapping relationship, wherein the residual heat generation is positively correlated with both the cumulative feed amount and the change slope.

[0041] Preferably, the residual calorific value is calculated using the following formula: ,in, This is the quantified value of residual heat. To accumulate the amount of material fed, This is the change in exhaust temperature. To preset the duration of the sliding time window, as well as These are the preset physical mapping coefficients for solid fuels.

[0042] Preferably, before step 101, an ignition control step is included: step 401, activating the ignition rod and turning on the screw feeder and blower; step 402, reading the exhaust temperature, and when the exhaust temperature reaches the preset ignition success threshold, confirming successful ignition and controlling the system to switch to step 101.

[0043] Preferably, it also includes a negative pressure monitoring safety protection step: step 501, using a negative pressure sensor to collect the negative pressure value inside the furnace in real time; step 502, determining whether the negative pressure value deviates from the preset safe negative pressure range; step 503, if the negative pressure value deviates from the preset safe negative pressure range, then shutting off the screw feeder and ignition rod, and increasing the speed of the blower to the preset exhaust speed.

[0044] Preferably, in step 105, the duration of the blower speed increase is 30s to 60s.

[0045] Preferably, step 106 further includes: step 1061, calculating the second derivative of the exhaust temperature in real time; step 1062, correcting the speed reduction slope of the blower based on the second derivative, so as to reduce the formation of carbon deposits inside the furnace.

[0046] Preferably, the method also includes a remote data synchronization step: step 801, synchronizing the indoor temperature and exhaust temperature to the cloud server via the wireless communication module; step 802, receiving the control command issued by the remote terminal, and updating the set temperature according to the control command.

[0047] Preferably, the preset temperature threshold is 1.5℃, and the method also includes a flashback warning step: Step 1001, monitor the pipeline temperature of the screw feeder; Step 1002, if the pipeline temperature exceeds the preset flashback warning threshold, shut down the screw feeder and output a warning signal.

[0048] A fireplace control system includes a sensor array, a feeding mechanism, a variable frequency fan, an ignition rod, and a main controller.

[0049] The sensor group includes an indoor temperature sensor, an exhaust temperature sensor, a furnace negative pressure sensor, and a feed temperature sensor. The sensor group is connected to the main controller.

[0050] Feeding mechanisms, including screw feeders, are used for controlled conveying or stopping the supply of solid pellet fuel;

[0051] Variable frequency fans are used to control the amount of combustion air inside the furnace.

[0052] The central controller is electrically connected to the sensor group, feeding mechanism, variable frequency fan, and ignition rod. Specifically, the central controller determines the trigger state of the power adjustment phase based on the temperature difference between the indoor temperature and the set temperature. Upon entering the power adjustment phase, it drives the feeding mechanism to stop feeding and disengages the proportional linkage control relationship between the feeding mechanism and the variable frequency fan. The central controller also calculates the residual heat generation based on the duty cycle of the screw feeder and the slope of the exhaust temperature change, and adjusts the output frequency of the variable frequency fan based on the airflow compensation gain determined by the residual heat generation. Furthermore, the central controller monitors the real-time decrease slope of the exhaust temperature and drives the variable frequency fan speed to decrease synchronously with the real-time decrease slope.

[0053] Example 1: During the ignition phase of the fireplace startup, the main control unit drives the glow plug to generate localized high temperatures and controls the screw feeder to deliver initial material to the furnace at an initial duty cycle of 20%. The system continuously polls the feedback voltage of the exhaust temperature sensor. Only when the value fed back by the exhaust temperature sensor exceeds the physical threshold of 45°C and is maintained for 120 seconds does the main control unit determine that the ignition process is complete and allow the system to switch to the temperature difference scanning logic between the indoor temperature and the set temperature. This standardized determination of the initial combustion state provides a basis for subsequent calculation of residual heat generation. To provide a stable physical baseline for the firebed, under conditions where the initial indoor temperature is low and the fireplace is continuously running at its highest power setting (P1), when the real-time temperature monitored by the indoor temperature sensor rises to the preset set temperature and the temperature difference between the two decreases to the critical range of 1.5℃, the system faces the risk of room temperature overshoot due to the thermal inertia of solid fuel combustion. If the main control unit simultaneously reduces the feeding frequency and air supply intensity according to traditional control logic, the fuel accumulated in the furnace will enter a low-oxygen smoldering state in an oxygen-deficient environment, leading to tar condensation in the exhaust pipe and causing the indoor temperature to exceed the set target value. In response to the trigger signal of the aforementioned critical range, the main control unit shuts off the screw feeder and releases its proportional linkage control relationship with the blower. The system calculates the cumulative feed amount by adjusting the operating duty cycle of the screw feeder within the preset sliding time window. The slope of the exhaust temperature change is determined by continuously collecting analog signals from an exhaust temperature sensor. It should be noted that the residual calorific value of this invention refers to the total residual heat expected to be released during the combustion phase of the existing solid fuel in the furnace after the feeding mechanism is shut off to stop supplying fuel to the furnace. Physically, it corresponds to a quantitative characterization of the physical mass and residual thermal potential of the material accumulated inside the furnace. The residual calorific value inside the furnace is calculated using the following formula. : ,in, This is the quantified value of residual heat. To accumulate the amount of material fed, This is the change in exhaust temperature. To preset the duration of the sliding time window, The slope of the change in exhaust temperature. and These are the preset physical mapping coefficients for solid fuels.

[0054] Based on the measured residual heat The main control unit reverses the drive voltage of the blower, causing its speed to jump to twice the base speed corresponding to the preset lowest power level P4 within 45 seconds. This enhanced oxygen supply condition rapidly burns off the fuel accumulated in the furnace. During the blower speed increase phase and the subsequent physical transition to steady-state shutdown, a large amount of room temperature cold air is continuously pumped into the furnace. The system's timing control logic here employs a strict serial step-by-step isolated execution mechanism. First, within the independent time limit specified in step 105, the blower is fully driven to reverse its speed increase, forcing oxygen supply to accelerate the consumption of the grate's remaining material. Only after the physical termination of this oxygen supply burnout period does the main control unit issue a control command to enter the follow-up adjustment stage in step 106. The first stage formally activates the synchronous reduction program of the blower speed. At the underlying physical and thermodynamic level, due to the huge gas dynamic heat removal effect introduced during the high-speed stage and the residual air remaining during the subsequent reduction process, the exhaust duct will continue to be physically cooled. This physical cooling effect caused by the cold air is macroscopically manifested as a complete physical evolution process that runs through these two continuous control stages. By using the hardware timer inside the main control unit to clearly define the digital boundary between the high air volume filling time and the subsequent follow-up decay period, it is ensured that the physical command for enhanced heat release and the control action for air volume withdrawal are carried out sequentially on the control logic axis, completely eliminating command overlap and logical direction conflict at the control action execution level. Based on the principle of mechanical airflow mixing, the system utilizes the combined effects of sensor feedback on exhaust temperature decrease, fuel consumption reduction, and physical dilution by cold air. It retrieves the real-time intake air mass flow rate corresponding to the current blower speed and calculates the physical cooling deviation caused by the introduction of cold air, using the specific heat capacity of ambient air. This cooling deviation is removed from the total exhaust temperature decrease, extracting the corrected exhaust temperature characterizing the pure combustion decay state. The system calculates the second derivative of the corrected exhaust temperature over time in real time, quantitatively isolating the cooling and dilution effects of non-combustion factors on the exhaust channel within the control closed loop. In addition to obtaining the real-time intake air mass flow rate and the specific heat capacity of the cold air, the main control unit further incorporates the pre-stored physical heat capacity benchmark of the furnace structure. The initial flue gas thermodynamic state measured by the exhaust temperature sensor at the moment of material shut-off is used as the boundary constraint condition. The determination path of this physical cooling deviation relies on the dynamic transient energy balance mechanism inside the furnace. The main control unit correlates the physical cooling flow of the externally introduced cold air with the non-adiabatic mixing and heat absorption process of the main flue gas flow inside the flue in the confined physical space through heat conservation. Thus, the heat exchange caused by the physical temperature difference of the fluid is qualitatively mapped to the total cooling attenuation contribution value of the exhaust temperature. This cooling deviation shows a monotonically positive increasing functional qualitative trend with the increase of the real-time intake mass flow rate, and is constrained by the maximum value limit of the convective heat transfer coefficient of the wind box pipeline at the fluid dynamic boundary.

[0055] In practical engineering control, the main control unit pre-calibrates through on-site experiments or engineering adjustments, determining the exhaust temperature drop decay curves under different fan speed gradients in a furnace with no material and pure ambient air flowing through. This calibration curve is stored as a fundamental feature in the read-only memory of the main control chip. During operation, the processor directly retrieves the corresponding temperature drop calibration value based on the current variable frequency fan output frequency as the physical cooling deviation, completing the closed-loop calculation of the pure combustion characteristic temperature. In acquiring these fluid dynamic parameters, the real-time intake mass flow rate is not based on a single speed value but rather on the actual aerodynamic resistance value synchronously collected by negative pressure sensors installed in the furnace components. The main control unit then... The blower speed data and furnace negative pressure feedback values ​​are matrix-concatenated and input into the pre-stored 3D surface mapping table of blower factory aerodynamic performance. A bilinear interpolation algorithm is used to lock the actual exhaust volume under this back pressure constraint. Then, combined with ambient air density, the mass flow rate of the cold air entering the furnace is accurately calculated, providing a rigorous fluid dynamics data source for subsequent cooling deviation analysis. Based on the laws of chemical reaction kinetics, the second derivative characterizes the decay acceleration of the combustion heat release process. When the main control unit detects a local negative extreme value feature point during dynamic monitoring, it indicates a sharp collapse in the combustion intensity of the firebed. The physical essence of this negative extreme value feature point refers to the local variation exhibited by the second derivative waveform of the corrected exhaust temperature during the negative half-cycle dynamic evolution. The inflection point of the wave trough represents a physical transient where the rate of heat release from combustion of the remaining fuel inside the furnace reaches an extreme amplification. This characteristic point is not a fixed, static, digital physical constant. Its capture and recognition mechanism lies in the time-series scanning of the dynamic waveform sequence by the main control unit. The main control unit compares the value of the second derivative of the current cycle with the value evolution trend of several consecutive historical sampling cycles in real time within each independent control sampling period. When it detects that the absolute value of the second derivative changes from monotonically increasing to monotonically decreasing, and its first difference value undergoes a zero-point physical switch, it determines that the local negative extreme characteristic point has been accurately captured on the time axis. The absolute temperature and derivative level at this characteristic point vary with the type of solid fuel being switched and the initial burner bed residue. The qualitative shift occurs due to changes in the quality of the remaining fuel, and is constrained by the physical boundary of the inherent volatile matter's basic oxidation exothermic intensity above the lower limit. During the on-site engineering tuning phase before product delivery, the main control unit conducts multiple sets of material burnout decay tests for different fuel load conditions, statistically analyzes the typical valley distribution range of the second derivative waveform, and uses this as a safety protection boundary for logic limiting, which is then programmed into the control chip. Through a hybrid closed-loop rule that primarily uses dynamic slope waveform capture and secondarily uses static calibration range constraint limiting, the system ensures that it can stably and accurately lock onto the critical time control node to prevent the firebed from extinguishing and collapsing. If there is a risk of entering the carbon-rich and oxygen-deficient zone, causing tar precipitation and smoldering, the system will immediately reduce the rate of decrease in blower speed proportionally based on the current absolute value.Delaying the withdrawal of combustion air forces the maintenance of oxygen partial pressure on the surface of the furnace, thus blocking the formation of free carbon and tar at the reactant concentration level. Specifically, the main control unit has a preset base speed reduction slope constant. In each control cycle, the absolute value of the second derivative of the exhaust temperature is extracted as a dynamic feedback quantity. This feedback absolute value is multiplied by the initially set proportional attenuation coefficient to obtain a slope correction term. The main control unit subtracts this slope correction term from the base speed reduction slope constant to calculate the corrected real-time speed reduction slope command, which is ultimately converted into a duty cycle reduction step in the pulse width modulation circuit. The output is sent to the blower frequency converter, achieving dynamic adaptation of the oxygen supply withdrawal rate to the combustion collapse acceleration at the physical hardware level. Simultaneously, the main control unit adjusts the drive frequency of the convection fan to maintain a proportional and synchronous decay as the exhaust temperature decreases. This utilizes residual heat in the furnace for heat compensation and guides the system into a stable cooling state until the exhaust temperature drops to the preset shutdown temperature. By using the existing processor within the system to asynchronously decouple the physical fuel delivery and combustion oxygen distribution logic, overshoot caused by the physical thermal inertia of solid fuel is eliminated, and carbon buildup in the exhaust pipe is suppressed.

[0056] Example 2: This example verifies the stability of the fireplace control method in dealing with the thermal inertia of solid pellet fuel. A 55-cubic-meter thermal balance test chamber was selected. An indoor temperature sensor with a sampling frequency of 1 Hz and a measurement accuracy of 0.1℃ was installed inside the chamber. A pellet fireplace equipped with a screw feeder, blower, and convection fan was used as the test subject. The exhaust temperature sensor was installed 150 mm upstream of the exhaust pipe outlet, with a measurement accuracy of 1.0℃. To simulate real exhaust turbulence interference, random noise fluctuations with an amplitude of 0.8℃ were injected into the signal link for acquiring the exhaust temperature. The duration of a preset sliding time window was also set. The time is set to 60 seconds, and the mean filtering characteristics of the preset sliding time window are used to suppress the slope of the change in exhaust temperature caused by random noise fluctuations. The impact of the calculation results.

[0057] The target temperature of the laboratory was set at 24℃. When the indoor temperature rose to the critical range of 22.5℃, the control group adopted a proportional linkage control method, that is, synchronously shutting down the screw feeder and switching the blower to the lowest power frequency; the sample group of this invention started asynchronous dissipation logic, that is, shutting down the screw feeder and adjusting the output based on the cumulative feed amount. slope of change with exhaust temperature Real-time calculation of residual heat generation This leads to a reverse jump in the blower speed to twice the base speed corresponding to the preset lowest power level P4. Test data indicates that, under the same fuel filling amount, the indoor temperature of the control group continued to climb to 25.86℃ after reaching the set value, resulting in a temperature overshoot of 1.86℃. Moreover, black tar-like carbon deposits adhered to the inner wall of the exhaust pipe after 20 consecutive cycle tests. Under the action of asynchronous dissipation logic, the sample group of this invention, by enhancing the oxygen supply condition, ensured that the fuel accumulated in the furnace was burned within 42.5 seconds, and the indoor temperature finally stabilized at 24.28℃, with the temperature overshoot reduced to 0.28℃, and the inner wall of the exhaust pipe remained dry.

[0058] Determine the optimal working window for the blower speed increase ratio, set a gradient comparison, and when the speed increase ratio is less than 1.5 times, the residual heat generation... Release rate is limited, and indoor temperature overshoot rises to 1.15℃; when the speed increase ratio exceeds 2.5 times, excessive cold air enters the furnace, causing the exhaust temperature to drop to 55.6℃, below the critical physical temperature point for tar condensation, resulting in condensate precipitation in the exhaust pipe. The speed increase ratio is then set to twice the base speed corresponding to the preset lowest power setting P4 to reduce residual heat generation. The release rate and heat exchange efficiency are balanced when the cumulative feed amount The residual heat generated by the system was calculated when the volume was 0.42 cubic decimeters, 0.85 cubic decimeters, and 1.26 cubic decimeters, respectively. The trend shows a linear increase, with corresponding blower speed reversal jump times of 28.6 seconds, 45.2 seconds, and 62.4 seconds, respectively. The above data confirms that the asynchronous dissipation logic achieves dynamic adaptation of oxygen supply compensation to fuel accumulation by quantitatively calculating residual energy. The test results confirm that the method of this invention has stable room temperature control accuracy under different operating loads, and the decoupled control logic effectively offsets the physical thermal inertia of solid fuel during the power regulation stage.

[0059] Example 3: When the fireplace system switches from wood pellet fuel to straw briquettes, the physical changes in the bulk density and calorific value of the fuel necessitate a re-measurement of the physical mapping coefficient of the solid fuel. and The discharge mass of the screw feeder per unit time at a fixed drive frequency was obtained by measurement, and the volumetric flow rate was determined by combining it with the density of straw briquettes, thus establishing the volume constant per unit duty cycle. Using the timer inside the main control unit, with a sampling period of 10 milliseconds. Poll the drive interface level of the screw feeder and count the total number of sampling points that are in a high-level state within a preset sliding time window. The cumulative feed amount is calculated according to the following logic. : ,in, To accumulate the amount of material fed, This represents the total number of high-level sampling points. The sampling period is Let be the volumetric flow rate constant per unit time. After obtaining the cumulative feed rate, control the fireplace to operate under different power loads until steady state, and record the slope of the exhaust temperature change after the screw feeder is turned off. The instantaneous heat flux density at the fireplace outlet is monitored synchronously and integrated over time to obtain the actual total heat generation inside the furnace. The actual total heat generation is used as the target parameter, and the cumulative feed rate is calculated. With the slope of change As the independent variable, the coefficient corresponding to the minimum value of the sum of squared residuals is calculated through mathematical fitting and used as the physical mapping coefficient of solid fuel. and For straw briquette fuel, the results obtained through testing The value is 4.2 megajoules per cubic decimeter. The value is 0.15 megajoules per °C.

[0060] When the indoor temperature rises to a level far from the set temperature At the critical range of 0.5℃, the main control unit modifies the pulse width modulation duty cycle value of its internal register to reduce the drive voltage of the screw feeder to 0 volts to stop material conveying. Simultaneously, the main control unit sends a step command to the blower's drive circuit, causing its corresponding pulse width modulation duty cycle to jump from 15% to 35%, increasing the saturation conduction time of the power MOSFET. This drives the blower's speed to double from the base speed within 45 seconds. This process utilizes the quantitatively calculated oxygen supply to offset the physical thermal inertia generated by the residual fuel, balancing the release rate of residual heat potential with the heat removal rate of the circulating fan. This eliminates room temperature fluctuations caused by changes in fuel physical properties and suppresses carbon buildup in the exhaust pipe. To utilize the measured residual calorific value... The signal is converted into an executable electronic control output signal, and the main control unit uses a proportional mapping algorithm to determine the air volume compensation gain. The specific logic is to calculate the residual heat generation. Compared with the preset physical reference heat The ratio is multiplied by a dimensionless correction factor, with a preset physical reference heat. Derived from the system's baseline load calibration procedure, the main control unit retrieves the steady-state heating power of the fireplace under rated full power settings. This steady-state heating power is multiplied by a preset sliding time window duration to obtain a physical reference baseline, with a correction factor applied. Based on the principle of excess air coefficient in combustion science, the system is set by pre-calibrating and testing the exhaust oxygen concentration under different airflow compensation conditions. The air compensation ratio corresponding to maintaining a stable furnace tail oxygen concentration within the 8% to 12% working range is selected as a fixed value. The calculation results are mapped to the duty cycle increment of a pulse width modulation signal. To compensate for the gain in air volume, This is a quantified value of residual heat, in megajoules. This is a preset physical reference heat, in megajoules. As a preset correction factor, this quantitative conversion between physical parameters ensures that the step amplitude of the drive voltage output by the main control unit is physically matched with the oxidation heat release requirements of the residual fuel in the furnace. In the pre-calibration test stage mentioned here, a wide-range zirconia oxygen concentration probe is fixed at the core flow layer of the fireplace exhaust port. When the system enters the steady state of preset physical reference heat dissipation, the blower is issued an exhaust volume increase command step by step in a fixed step size. The test host continuously obtains the surface oxygen partial pressure signal returned by the zirconia probe and fits it to form a physical response curve of exhaust volume and tail oxygen concentration. The exhaust compensation ratio value at the center point of the tail oxygen concentration of exactly 10% on the response curve is extracted and burned into the read-only memory of the central controller as a constant, which constitutes the underlying physical source of the dimensionless correction factor.

[0061] Example 4: When the system faces switching between various particle fuels with different physical compositions and calorific values, the main control unit pre-stores a parameter index table based on multi-dimensional fuel characteristics. This index table is obtained by measuring the moisture content, ash content, and bulk density of the fuel under controlled conditions. The specific calibration process includes placing fuel samples with known physical properties in a reference furnace equipped with an exhaust temperature monitoring system. The system operates under a standard environment with an ambient temperature of 20°C and an atmospheric pressure of 101.325 kPa. By recording the steady-state exhaust temperature of each fuel sample at a preset feeding frequency and the temperature decay curve after the feeding is turned off, and by using a calorimeter to calculate the corresponding actual calorific value, the physical properties of different fuel samples are mapped to the physical properties of solid fuels. as well as A quantitative mapping relationship is established and stored in memory. Upon receiving a fuel type selection signal, the system automatically loads the matching physical parameters and uses a preset digital index to support the residual calorific value. The accuracy of the calculation logic in reproducing different material properties.

[0062] In the on-site deployment scenario after the fireplace system has been physically installed, due to differences in the geometric topology of the exhaust duct, chimney height, and geographical altitude affecting the physical constraints on exhaust resistance, the system establishes a physical benchmark for exhaust temperature feedback by initiating a pre-calibration program. This drives the blower to operate at a preset power level speed gradient in a fuel-free state, real-time acquiring the response characteristics of the exhaust temperature sensor under different intake loads, and utilizing on-site measured atmospheric pressure parameters to determine the duration of a preset sliding time window. To correct deviations, the main control unit automatically records and locks the initial response characteristics of the exhaust temperature at the trigger point during the power adjustment phase. Utilizing physical parameter calibration specific to the installation environment, it achieves asynchronous dissipation under different exhaust back pressure environments by varying the slope. By quantifying and capturing residual energy, the system maintains the stability of combustion conditions by mapping the blower speed increase command when reducing output power.

[0063] Example 5: In a design scenario that optimizes the sensitivity of exhaust gas detection, the physical coordinate offset of the exhaust temperature sensor can cause a nonlinear change in the sampling thermal hysteresis time constant, thereby interfering with the residual heat generation. To ensure measurement accuracy, the system initiates a geometric calibration procedure to determine the physical location of the exhaust temperature sensor. Temperature sampling points are set at 50 mm intervals along the physical axis downstream of the furnace outlet. By comparing the temperature drop gradient envelopes fed back from each sampling point at the moment the screw feeder is turned off, the physical coordinates with the largest absolute slope and a signal-to-noise ratio higher than 25 dB are selected as the installation points. Based on this, the system utilizes the pulse resolution of the screw feeder to determine the duration of the preset sliding time window. Correcting deviations and calculating the fundamental frequency period of the output pulse sequence of the screw feeder. And Set as 100 times, of which, The fundamental frequency period of the output pulse sequence of the screw feeder. The quantization window is set to the duration of the preset sliding time window, and the collected cumulative feed amount is... The data covers no fewer than 100 complete physical feeding cycles.

[0064] In the pre-installation self-test scenario after the fireplace system's physical installation is complete, the system uses the rated current benchmark of the blower during the reverse boost phase to determine the physical resistance state of the exhaust duct. The main control unit drives the blower to complete the power step boost in a fuel-free state and collects drive current data in real time. When the blower's drive current is detected to exceed 1.2 times the preset rated current benchmark for 5 consecutive sampling points, the main control unit determines that there is an abnormal back pressure in the exhaust duct and automatically reduces the blower's speed boost gain. By utilizing an online fault-tolerant method for installation environment deviations and abnormal operating conditions, the asynchronous dissipation logic can correct the air volume compensation parameters according to the actual physical constraints of the flue during the power adjustment phase, thus realizing the residual heat generation under different installation conditions. Physical offsetting of the measured results; in the operating condition switching scenario after the asynchronous dissipation command is executed, when the exhaust temperature drops to the preset physical inflection point and the rate of change of the indoor temperature... When the temperature approaches 0, the main control unit determines the residual heat generation in the furnace. The system has been completely ventilated by the convection circulation fan. The system selects instructions to execute actions according to the preset operating mode. If a shutdown command is received, the power supply to all actuators is directly cut off. If the system is in energy-saving maintenance mode, the proportional linkage between the screw feeder and the blower is reactivated. Through this logical closure from the power regulation stage to the steady-state maintenance stage, physical control of the entire cycle of solid fuel combustion is achieved.

[0065] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A fireplace control method, characterized in that, Includes the following steps: Step 101: Obtain the indoor temperature and exhaust temperature in real time, and retrieve the preset set temperature; Step 102: Calculate the temperature difference between the indoor temperature and the set temperature, and determine that the system enters the power regulation stage when the temperature difference decreases to the preset temperature threshold. Step 103: In response to the triggering of the power regulation stage, the screw feeder is turned off and the proportional linkage control relationship between the screw feeder and the blower is released to stop the supply of fuel to the furnace. Step 104: Obtain the cumulative feed amount within the preset sliding time window before shutting off the screw feeder, and calculate the slope of the exhaust temperature change within the preset sliding time window to measure the residual heat generation inside the furnace. Step 105: Determine the air volume compensation gain for offsetting thermal inertia based on the residual heat generation, and increase the speed of the blower according to the air volume compensation gain, so as to burn off the remaining fuel in the furnace by using the increased oxygen supply. Step 106: Monitor the real-time rate of decrease of exhaust temperature and control the speed of the blower to decrease synchronously with the real-time rate of decrease until the exhaust temperature drops to the preset shutdown temperature point. Step 104 further includes: Step 1041, retrieving the operating duty cycle of the screw feeder within a preset sliding time window, and calculating the cumulative feed amount based on the operating duty cycle; Step 1042, converting the cumulative feed amount and the change slope into residual heat generation using a preset physical mapping relationship, wherein the residual heat generation is positively correlated with both the cumulative feed amount and the change slope. The residual calorific value is calculated using the following formula: ,in, This is the quantified value of residual heat. To accumulate the amount of material fed, This is the change in exhaust temperature. To preset the duration of the sliding time window, as well as These are the preset physical mapping coefficients for solid fuels.

2. The fireplace control method according to claim 1, characterized in that, Before step 101, there is also an ignition control step: Step 401, activate the ignition rod and turn on the screw feeder and blower; Step 402, read the exhaust temperature, and when the exhaust temperature reaches the preset ignition success threshold, determine that the ignition is successful and control the system to switch to step 101.

3. A fireplace control method according to claim 1, characterized in that, It also includes a negative pressure monitoring safety protection step: Step 501, using a negative pressure sensor to collect the negative pressure value inside the furnace in real time; Step 502, determining whether the negative pressure value deviates from the preset safe negative pressure range; Step 503: If the negative pressure value deviates from the preset safe negative pressure range, shut off the screw feeder and ignition rod, and increase the speed of the blower to the preset exhaust speed.

4. A fireplace control method according to claim 1, characterized in that, In step 105, the blower speed increase lasts for 30 to 60 seconds.

5. A fireplace control method according to claim 1, characterized in that, Step 106 further includes: Step 1061, calculating the second derivative of the exhaust temperature in real time; Step 1062, correcting the speed reduction slope of the blower based on the second derivative to reduce carbon buildup inside the furnace.

6. A fireplace control method according to claim 1, characterized in that, It also includes a remote data synchronization step: Step 801, synchronizing the indoor temperature and exhaust temperature to the cloud server through the wireless communication module; Step 802, receiving the control command issued by the remote terminal, and updating the set temperature according to the control command.

7. A fireplace control method according to claim 1, characterized in that, The preset temperature threshold is 1.5℃, and it also includes a flashback warning step: Step 1001, monitor the pipeline temperature of the screw feeder; Step 1002, if the pipeline temperature exceeds the preset flashback warning threshold, shut down the screw feeder and output a warning signal.

8. A fireplace control system for implementing the fireplace control method of claim 1, characterized in that, Includes sensor array, feeding mechanism, variable frequency fan, ignition rod, and main controller: The sensor group includes an indoor temperature sensor, an exhaust temperature sensor, a furnace negative pressure sensor, and a feed temperature sensor. The sensor group is connected to the main controller. Feeding mechanisms, including screw feeders, are used for controlled conveying or stopping the supply of solid pellet fuel; Variable frequency fans are used to control the amount of combustion air inside the furnace. The central controller is electrically connected to the sensor group, feeding mechanism, variable frequency fan, and ignition rod. Specifically, the central controller determines the trigger state of the power adjustment phase based on the temperature difference between the indoor temperature and the set temperature. Upon entering the power adjustment phase, it drives the feeding mechanism to stop feeding and disengages the proportional linkage control relationship between the feeding mechanism and the variable frequency fan. The central controller also calculates the residual heat generation based on the duty cycle of the screw feeder and the slope of the exhaust temperature change, and adjusts the output frequency of the variable frequency fan based on the airflow compensation gain determined by the residual heat generation. Furthermore, the central controller monitors the real-time decrease slope of the exhaust temperature and drives the variable frequency fan speed to decrease synchronously with the real-time decrease slope.

Images