Automatic temperature adjusting device and method for movable grain dryer

Abstract

The invention discloses an automatic temperature adjusting device and method for a movable grain dryer. The dryer comprises a hot air bin, a heat exchanger and an air blower. The heat exchanger is provided with a combustion chamber, a smoke collecting ring, a smoke distribution chamber, a heat exchange pipe, a smoke exhaust pipe and a fuel oil burner. The automatic temperature adjusting device comprises a control system, a fuel oil flow proportion adjusting valve, a fuel oil atomization air proportion adjusting valve, a combustion air proportion adjusting valve and a temperature monitoring device. The temperature monitoring device is composed of a plurality of temperature sensors which are arranged in the circumferential direction of the heat exchanger and the axial direction of the combustion chamber and connected with the control system through a data acquisition card. Real-time monitoring of a three-dimensional temperature field is achieved through two-dimensional sensor layout, temperature distribution is accurately captured, thermal disturbance is predicted in combination with a feed-forward compensation algorithm, the fuel oil flow and the opening degree of an atomization air and combustion air proportional valve are synchronously adjusted, accurate temperature control is achieved, and the control precision is high. The problem of local over-drying or mildewing of grains caused by non-uniform heat exchange of a traditional dryer is effectively solved, and the drying quality is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of grain drying, and in particular to an automatic temperature control device and method for a mobile grain dryer. Background Art

[0002] After harvest, grain typically has a high moisture content, requiring rapid and thorough drying to ensure safe storage and prevent mold and other problems. Statistics show that over 5% of grain is lost annually due to untimely or inadequate drying. In particular, in June, some major grain-producing areas often experience "rotten field rain," which further increases the risk of grain becoming damp and exacerbates losses. In emergency drying scenarios, due to the complex environment and high moisture content of wet grain, current grain drying equipment has numerous shortcomings, such as low heat exchange efficiency, immobile equipment, and slow precipitation rates, making it difficult to meet the practical needs of disaster prevention, emergency response, and rapid loss reduction.

[0003] Existing mobile dryers have a low degree of automation, and the adjustment of drying parameters still relies on manual experience. The operating environment during emergency drying varies greatly. These conditions are not conducive to the stable supply of drying heat. It is difficult to control the stability of the hot air temperature according to changes in ambient temperature and humidity. The temperature control accuracy is low, which can easily cause problems such as uneven drying and low efficiency in extreme weather, thereby affecting the quality of drying.

[0004] In the prior art, patent CN 107062878 A provides a mobile grain dryer heat circulation system and its control method. The system includes a burner, a heat exchanger, a fan and other components. The heat exchanger has spiral tubes and rotating blades, which can extend the residence time of hot air and improve the heat exchange efficiency. The control method adjusts the air volume through the fan, and pressurizes the burner for a second time, so that the hot air circulates and heats in the heat exchanger, generating high-temperature hot air to dry the grain, and the exhaust gas is discharged through the chimney. This patent has the following disadvantages: (1) The control strategy mainly focuses on the fan air volume adjustment, and the control means are single; (2) Although spiral guide vanes are added to the heat exchange tubes used, the heat exchange efficiency is still low, resulting in heat waste.

[0005] Other existing technologies have methods for controlling the temperature by controlling the fuel flow of the burner and the mixing ratio of the atomized fuel and air according to the target temperature. However, this method cannot adapt to changes in the external environment to achieve precise temperature control. Summary of the Invention

[0006] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an automatic temperature control device and method for a mobile grain dryer, which has high temperature control accuracy and can timely adjust the operating parameters of the burner based on the ambient temperature and humidity.

[0007] Technical solution: To achieve the above-mentioned purpose, the present invention provides an automatic temperature control device for a mobile grain dryer. The mobile grain dryer includes a hot air bin and a heat exchanger installed in the hot air bin, the hot air bin having an air inlet connected to a blower; the heat exchanger includes a cylindrical combustion chamber, the front and rear ends of the combustion chamber respectively having a smoke collecting ring and a smoke distribution chamber, a plurality of heat exchange tubes arranged around the combustion chamber are connected between the smoke collecting ring, and the smoke collecting ring is connected to a smoke exhaust pipe; the front end of the combustion chamber is connected to a fuel burner;

[0008] The fuel burner injects atomized fuel and air into the combustion chamber for combustion. The smoke generated by the combustion first enters the smoke distribution chamber, and then enters the heat exchange tubes from the smoke distribution chamber. Then, the heat exchange tubes converge to the smoke collecting ring and finally are discharged from the exhaust pipe.

[0009] The air inlet of the hot air bin is located on the side close to the smoke collecting ring. The air blown into the air inlet flows perpendicular to the axial direction of the combustion chamber. After entering the hot air bin, the airflow turns and flows along the axial direction of the combustion chamber, absorbing heat from the outer wall of the combustion chamber and the outer wall of the heat exchange tube to become hot air for grain drying.

[0010] The automatic temperature control device includes a control system, a fuel flow ratio control valve, a fuel atomization air ratio control valve and a temperature monitoring device; each control valve and the temperature monitoring device are connected to the control system, which includes a host computer and a PLC controller;

[0011] The temperature monitoring device includes a plurality of temperature sensors installed in the hot air chamber, and all the temperature sensors are dispersed in two dimensions, the circumferential direction of the heat exchanger and the axial direction of the combustion chamber; all the temperature sensors are connected to the control system via a data acquisition card;

[0012] The automatic temperature control device also includes a combustion air ratio control valve;

[0013] The control system is configured to construct a three-dimensional temperature field in the hot air bin based on the data collected by all the temperature sensors, thereby predicting the thermal disturbance trend and generating feedforward compensation instructions, and dynamically adjusting the openings of the fuel flow ratio control valve, the fuel atomization air ratio control valve, and the combustion air ratio control valve.

[0014] Furthermore, the temperature monitoring device includes two groups of sensor groups placed at the air inlet and the air outlet, and at least one group of sensor groups is arranged between the two groups of sensor groups. Each group of sensor groups includes multiple temperature sensors arranged around the heat exchanger.

[0015] Among them, the group of sensors placed at the air inlet position includes at least one temperature sensor facing the air inlet, so that the temperature of the incoming air can be collected.

[0016] Furthermore, the temperature monitoring device further includes a first flue gas temperature sensor and a second flue gas temperature sensor respectively arranged at the flue gas distribution chamber and the outlet of the flue gas exhaust pipe.

[0017] Furthermore, the heat exchange tube is a curved spiral shape that is less than one turn, that is, when viewed from the axial direction of the combustion chamber, the heat exchange tube extends along a non-closed arc; the heat exchanger includes two inner and outer groups of tubes composed of the heat exchange tubes, and the rotation directions of the heat exchange tubes corresponding to the inner and outer groups of tubes are opposite.

[0018] An automatic temperature control method for a mobile grain dryer is applied to the above-mentioned automatic temperature control device, and the method comprises:

[0019] The temperature data of all the temperature sensors are collected by the data acquisition card to obtain the temperature field information in the hot air chamber;

[0020] Performing spatiotemporal sequence analysis based on the temperature field information to predict the disturbance trend and disturbance amount occurring in the heat exchanger;

[0021] A compensation amount is calculated based on the disturbance trend and the disturbance amount, and the openings of the fuel flow ratio regulating valve, the fuel atomizing air ratio regulating valve, and the combustion air ratio regulating valve are adjusted.

[0022] Furthermore, the data acquisition card applies a sliding average filter to the temperature data collected by each temperature sensor, and its sampling frequency can be dynamically adjusted based on temperature differences. Specifically, the larger the temperature field gradient data, the higher the sampling frequency; the smaller the temperature field gradient data, the lower the sampling frequency. This allows the amount of collected data to be determined on demand, reducing data processing workload.

[0023] Furthermore, the calculating of the compensation amount based on the disturbance trend and the disturbance amount, and adjusting the openings of the fuel flow ratio regulating valve, the fuel atomizing air ratio regulating valve, and the combustion air ratio regulating valve includes:

[0024] Obtain the air humidity change rate ΔH through the ambient humidity sensor;

[0025] Based on the temperature deviation ΔT and the air humidity change rate ΔH, the compensation coefficients K1, K2, and K3 corresponding to the fuel flow ratio control valve, the fuel atomization air ratio control valve, and the combustion air ratio control valve are calculated:

[0026]

[0027] Among them: K p , K i , K d are all preset weight coefficients; ΔT is the temperature deviation, which is the weighted comprehensive value of the temperature deviation of each detection point in the temperature field; represents the cumulative temperature deviation; represents the temperature change rate; α is the fuel weighting factor; β is the humidity weighting factor; γ is the combustion coupling coefficient;

[0028] The target opening corresponding to each proportional control valve is calculated based on the compensation coefficient, and each proportional control valve is adjusted accordingly; the target opening is the product of the compensation coefficient and the reference opening of the corresponding proportional control valve.

[0029] Beneficial effects: The automatic temperature control device and method for a mobile grain dryer of the present invention have the following beneficial effects:

[0030] (1) The automatic temperature control device of the present invention realizes real-time monitoring of the three-dimensional temperature field in the hot air bin through the axial + circumferential dual-dimensional sensor layout, accurately captures the temperature distribution in the hot air bin, analyzes the temperature field in the hot air bin and predicts the change trend, compensates the system output through the feedforward link, and dynamically adjusts the opening of the three-way proportional valve of fuel flow, atomizing air and combustion air synchronously to achieve precise temperature control of temperature fluctuations, effectively solving the problem of local over-drying or mildew of grains caused by uneven heat exchange in traditional dryers during emergency operations, and can ensure the drying quality.

[0031] (2) With the above-mentioned layout, the temperature data group collected by the temperature monitoring device can reflect the multi-dimensional data of the airflow inlet temperature, air outlet temperature and temperature rise characteristics of the airflow, which makes it easier for the control system to know the heating characteristics of the airflow in the hot air chamber by the heat exchanger, and is more convenient to change the working parameters of the combustion chamber to control the airflow temperature.

[0032] (3) In the heat exchanger, by setting up two groups of inner and outer tubes with opposite spiral directions, the heat exchange area is greatly increased while ensuring the total number of heat exchange tubes, which can improve the heat exchange efficiency. When the air flow passes through different layers of heat exchange tubes, it generates alternating flow directions, forming turbulence to improve the heat transfer coefficient.

[0033] (4) The calculation of the correction coefficient of each proportional control valve not only takes into account the temperature deviation, but also takes into account the influence of the change in external air humidity on the fuel combustion rate and the additional combustion loss caused by wet air. On the basis of the traditional fuel flow regulation and fuel-air mixing ratio regulation, the present invention adds a combustion air ratio regulating valve. Through the coordinated regulation of the three regulating valves, the fuel combustion rate can be effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1This is a structural diagram of an automatic temperature control device for a mobile grain dryer;

[0035] Figure 2 The present invention is a three-dimensional structural diagram of an automatic temperature control device for a mobile grain dryer;

[0036] Figure 3 The figure is a cross-sectional structural diagram of an automatic temperature control device for a mobile grain dryer;

[0037] Figure 4 for Figure 1 AA cross-sectional structural diagram in;

[0038] Figure 5 It is the structural diagram of the heat exchanger;

[0039] Figure 6 Schematic diagram of the automatic temperature control device;

[0040] Figure 7 Schematic diagram of the process of automatic temperature control method.

[0041] In the figure: 1-hot air bin; 2-heat exchanger; 21-combustion chamber; 22-smoke distribution chamber; 23-smoke collecting ring; 24-heat exchange tube; 25-smoke exhaust pipe; 26-oil burner; 3-blower; 4-automatic temperature control device; 41-control system; 42-fuel flow ratio control valve; 43-fuel atomizing air ratio control valve; 44-temperature sensor; 45-combustion air ratio control valve; 46-data acquisition card; 5-smoke turbulence device; 51-regulating cylinder; 52-partition. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to the accompanying drawings.

[0043] like Figures 1 to 3 The automatic temperature control device for a mobile grain dryer shown in the figure comprises a hot air bin 1 and a heat exchanger 2 installed in the hot air bin 1. The hot air bin 1 has an air inlet connected to a blower 3. The heat exchanger 2 comprises a cylindrical combustion chamber 21. The front and rear ends of the combustion chamber 21 respectively have a smoke collecting ring 23 and a smoke distribution chamber 22. A plurality of heat exchange tubes 24 arranged around the combustion chamber 21 are connected between the smoke collecting ring 23 and the smoke collecting ring 23. The smoke collecting ring 23 is connected to a smoke exhaust pipe 25. The front end of the combustion chamber 21 is connected to a fuel burner 26.

[0044] The fuel burner 26 injects atomized fuel and air into the combustion chamber 21 for combustion. The smoke generated by the combustion first enters the smoke distribution chamber 22, then enters the heat exchange tubes 24, and then converges to the smoke collecting ring 23 through the heat exchange tubes 24, and finally is discharged from the exhaust pipe 25.

[0045] The air inlet of the hot air bin 1 is located on the side close to the smoke collecting ring 23. The air blown into the air inlet by the blower 3 flows perpendicular to the axial direction of the combustion chamber 21. After entering the hot air bin 1, the airflow turns and flows along the axial direction of the combustion chamber 21, absorbing heat from the outer wall of the combustion chamber 21 and the outer wall of the heat exchange tube 24 to become hot air for grain drying.

[0046] like Figure 6 As shown, the automatic temperature control device includes a control system 41, a fuel flow ratio control valve 42, a fuel atomization air ratio control valve 43 and a temperature monitoring device; each control valve and the temperature monitoring device are connected to the control system 41, and the control system 41 includes a host computer and a PLC controller;

[0047] The temperature monitoring device includes a plurality of temperature sensors 44 installed in the hot air chamber 1. All the temperature sensors 44 are distributed in two dimensions, circumferentially of the heat exchanger 2 and axially of the combustion chamber 21. All the temperature sensors 44 are connected to the control system 41 via a data acquisition card 46.

[0048] The automatic temperature control device further includes a combustion air ratio control valve 45;

[0049] The control system is configured to construct a three-dimensional temperature field of the hot air bin based on the data collected by all the temperature sensors 44, thereby predicting the thermal disturbance trend and generating feedforward compensation instructions, and dynamically adjusting the opening of the fuel flow ratio control valve 42, the fuel atomization air ratio control valve 43 and the combustion air ratio control valve 45.

[0050] The automatic temperature control device of the present invention realizes real-time monitoring of the three-dimensional temperature field in the hot air bin 1 through the axial + circumferential two-dimensional sensor layout, accurately captures the temperature distribution in the hot air bin, combines the feedforward compensation algorithm to predict the thermal disturbance trend, and synchronously and dynamically adjusts the opening of the three-way proportional valve of fuel flow, atomizing air and combustion air to achieve precise temperature control of temperature fluctuations, effectively solving the problem of local over-drying or mildew of grain caused by uneven heat exchange in traditional dryers during emergency operations, and can ensure the drying quality.

[0051] Preferably, the temperature monitoring device includes two groups of sensor groups placed at the air inlet and the air outlet, and at least one group of sensor groups is arranged between the two groups of sensor groups. Each group of sensor groups includes multiple temperature sensors 44 arranged around the heat exchanger 2. Figure 4 FIG. 4 is a distribution diagram of one group of temperature sensors 44 .

[0052] Among them, the group of sensors placed at the air inlet position includes at least one temperature sensor 44 facing the air inlet, so that the temperature of the incoming air can be collected.

[0053] By adopting the above-mentioned layout, the temperature data group collected by the temperature monitoring device can reflect the multi-dimensional data of the inlet temperature, outlet temperature and temperature rise characteristics of the airflow, which makes it easier for the control system to know the heating characteristics of the airflow in the hot air bin 1 by the heat exchanger 2, and is more convenient to change the working parameters of the combustion chamber 21 to regulate the airflow temperature.

[0054] Preferably, the temperature monitoring device further includes a first flue gas temperature sensor and a second flue gas temperature sensor, which are respectively arranged at the outlet positions of the flue gas distribution chamber 22 and the flue gas exhaust pipe 25. Based on the two flue gas temperature sensors, the control system can obtain heat exchange rate data accordingly. Preferably, a flue gas turbulence device 5 can be provided in the flue gas distribution chamber 22 to adjust the flow rate of the flue gas. Accordingly, the heat exchange rate can be adjusted to prevent the exhaust flue gas from being too hot and causing heat energy waste. The flue gas turbulence device 5 includes an adjustment cylinder 51 coaxially arranged with the flue gas distribution chamber 22. The length of the adjustment cylinder 51 is shorter than the length of the flue gas distribution chamber 22. There is an annular gap between the adjustment cylinder 51 and the flue gas distribution chamber 22. A plurality of partitions 52 are provided in the annular gap. Each partition 52 is provided with through holes arranged in a circumferential array, and the distribution ranges of the corresponding through holes on adjacent partitions 52 are staggered. The regulating tube 51 can adjust its position in the axial direction of the flue gas distribution chamber 22; when the regulating tube 51 is docked with the rear end of the combustion chamber 21, there is a gap between the rear end of the regulating tube 51 and the rear end of the combustion chamber 21, and all flue gases pass through the gap and the annular gap and enter the heat exchange tube 24 after being slowed down by the partition 52, which can reduce the flue gas flow rate and improve the heat exchange rate; when there is a gap between the regulating tube 51 and the rear end of the combustion chamber 21 and between the rear end of the combustion chamber 21, the flue gas can be diverted so that part of the flue gas directly enters the heat exchange tube 24, and part of the flue gas enters the heat exchange tube 24 through the partition 52 in the annular gap. By changing the axial position of the regulating tube 51, the flue gas flow rate can be accurately adjusted and the heat exchange rate can be accurately adjusted. After adjustment, the heat exchange characteristics of all heat exchange tubes can be regained based on the three-dimensional temperature field of the hot air bin.

[0055] Preferably, if Figure 5 As shown, the heat exchange tube 24 is a curved spiral shape that is less than one turn, that is, when viewed from the axial direction of the combustion chamber 21, the heat exchange tube 24 extends along a non-closed arc; the heat exchanger 2 includes an inner and outer tube groups consisting of the heat exchange tubes 24, and the rotation directions of the heat exchange tubes 24 corresponding to the inner and outer tube groups are opposite.

[0056] In heat exchanger 2, by providing two groups of inner and outer tubes with opposite spiral directions, the heat exchange area is greatly increased while ensuring the total number of heat exchange tubes, which can improve the heat exchange efficiency. When the airflow passes through different layers of heat exchange tubes, it generates alternating flow directions, forming turbulence to improve the heat transfer coefficient.

[0057] An automatic temperature control method for a mobile grain dryer is applied to the above-mentioned automatic temperature control device, such as Figure 7 As shown, the method includes the following steps S101-S103:

[0058] Step S101, collecting temperature data from all the temperature sensors 44 through the data acquisition card 46, and obtaining temperature field information in the hot air chamber 1 based on the data;

[0059] Step S102: performing a spatiotemporal sequence analysis based on the temperature field information to predict the disturbance trend and disturbance amount occurring in the heat exchanger 2;

[0060] In step S103 , a compensation amount is calculated based on the disturbance trend and the disturbance amount, and the openings of the fuel flow ratio regulating valve 42 , the fuel atomizing air ratio regulating valve 43 , and the combustion air ratio regulating valve 45 are adjusted.

[0061] Preferably, the data acquisition card 46 performs a sliding average filter on the temperature data collected by each temperature sensor 44, and its sampling frequency can be dynamically adjusted according to the temperature difference. Specifically, the larger the temperature field gradient data, the higher the sampling frequency, and the smaller the temperature field gradient data, the lower the sampling frequency. In this way, the amount of data collected can be determined as needed, reducing the amount of data processing.

[0062] Preferably, the calculation of the compensation amount based on the disturbance trend and the disturbance amount, and the adjustment of the openings of the fuel flow ratio regulating valve 42, the fuel atomizing air ratio regulating valve 43, and the combustion air ratio regulating valve 45 in the above step S103 include the following steps S201-S203:

[0063] Step S201, obtaining the air humidity change rate ΔH through the environmental humidity sensor;

[0064] Step S202 , based on the temperature deviation ΔT and the air humidity change rate ΔH, the compensation coefficients K1 , K2 , and K3 corresponding to the fuel flow ratio control valve 42 , the fuel atomization air ratio control valve 43 , and the combustion air ratio control valve 45 are calculated:

[0065]

[0066] Among them: K p , K i , K d are all preset weight coefficients; ΔT is the temperature deviation, which is the weighted comprehensive value of the temperature deviation of each detection point in the temperature field; represents the cumulative temperature deviation; represents the temperature change rate; α is the fuel weighting factor; β is the humidity weighting factor; γ is the combustion coupling coefficient;

[0067] Step S203 , calculating the target opening corresponding to each proportional control valve based on the compensation coefficient, and adjusting each proportional control valve accordingly; the target opening is the product of the compensation coefficient and the reference opening of the corresponding proportional control valve.

[0068] The calculation of the correction coefficient of each proportional control valve not only takes into account the temperature deviation, but also takes into account the impact of changes in external air humidity on the fuel combustion rate and the additional combustion loss caused by wet air. On the basis of traditional fuel flow regulation and fuel-air mixing ratio regulation, the present invention adds a combustion air ratio control valve 45. Through the coordinated regulation of the three control valves, the fuel combustion rate can be effectively guaranteed.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An automatic temperature control device for a mobile grain dryer, the mobile grain dryer comprising a hot air bin (1) and a heat exchanger (2) installed in the hot air bin (1), the hot air bin (1) having an air inlet, the air inlet being connected to a blower (3); the heat exchanger (2) comprising a combustion chamber (21), the front and rear ends of the combustion chamber (21) respectively comprising a smoke collecting ring (23) and a smoke distribution chamber (22), a plurality of heat exchange tubes (24) arranged around the combustion chamber (21) being connected between the smoke collecting ring (23) and the smoke collecting ring (23), the smoke collecting ring (23) being connected to a smoke exhaust pipe (25); the front end of the combustion chamber (21) being connected to a fuel burner (26); The automatic temperature control device includes a control system (41), a fuel flow ratio control valve (42), a fuel atomization air ratio control valve (43), and a temperature monitoring device; Its characteristics are: The temperature monitoring device comprises a plurality of temperature sensors (44) installed in the hot air chamber (1), all of the temperature sensors (44) being dispersedly arranged in two dimensions, circumferentially of the heat exchanger (2) and axially of the combustion chamber (21); all of the temperature sensors (44) being connected to the control system (41) via a data acquisition card (46); The automatic temperature control device further includes a combustion air ratio control valve (45); The control system is configured to construct a three-dimensional temperature field of the hot air bin based on the data collected by all the temperature sensors (44), predict the thermal disturbance trend and generate feedforward compensation instructions based on the data, and dynamically adjust the openings of the fuel flow ratio control valve (42), the fuel atomization air ratio control valve (43) and the combustion air ratio control valve (45).

2. The automatic temperature regulating device for a mobile grain dryer according to claim 1, characterized in that: The temperature monitoring device comprises two sensor groups placed at the air inlet and the air outlet, at least one sensor group is arranged between the two sensor groups, and each sensor group comprises a plurality of temperature sensors (44) arranged around the heat exchanger (2).

3. The automatic temperature regulating device for a mobile grain dryer according to claim 1, characterized in that: The temperature monitoring device further comprises a first flue gas temperature sensor and a second flue gas temperature sensor which are respectively arranged at the outlet positions of the flue gas distribution chamber (22) and the flue gas exhaust pipe (25).

4. The automatic temperature regulating device for a mobile grain dryer according to claim 1, characterized in that: The heat exchange tube (24) is in a curved spiral shape with less than one turn; the heat exchanger (2) comprises two inner and outer tube groups consisting of the heat exchange tubes (24), and the heat exchange tubes (24) corresponding to the inner and outer tube groups have opposite rotation directions.

5. An automatic temperature control method for a mobile grain dryer, applied to the automatic temperature control device according to any one of claims 1 to 4, characterized in that: Methods include: The temperature data of all the temperature sensors (44) are collected by the data acquisition card (46), thereby obtaining the temperature field information in the hot air bin (1); Performing a spatiotemporal sequence analysis based on the temperature field information to predict the disturbance trend and disturbance amount occurring in the heat exchanger (2); A compensation amount is calculated based on the disturbance trend and the disturbance amount, and the openings of the fuel flow ratio regulating valve (42), the fuel atomizing air ratio regulating valve (43) and the combustion air ratio regulating valve (45) are adjusted.

6. The automatic temperature control method for a mobile grain dryer according to claim 5, characterized in that: The data acquisition card (46) performs sliding average filtering on the temperature data collected by each temperature sensor (44), and its sampling frequency can be dynamically adjusted according to the temperature difference change.

7. The automatic temperature control method for a mobile grain dryer according to claim 5, characterized in that: The method of calculating the compensation amount based on the disturbance trend and the disturbance amount and adjusting the openings of the fuel flow ratio regulating valve (42), the fuel atomizing air ratio regulating valve (43) and the combustion air ratio regulating valve (45) comprises: Obtain the air humidity change rate ΔH through the ambient humidity sensor; Input values K1, K2, and K3 corresponding to the fuel flow ratio regulating valve (42), the fuel atomizing air ratio regulating valve (43), and the combustion air ratio regulating valve (45) are calculated based on the temperature deviation ΔT and the air humidity change rate ΔH: Among them: K p , K i , K d are all preset weight coefficients; ΔT is the temperature deviation, which is the weighted comprehensive value of the temperature deviation of each detection point in the temperature field; represents the cumulative temperature deviation; represents the temperature change rate; α is the fuel weighting factor; β is the humidity weighting factor; γ is the combustion coupling coefficient; The target opening corresponding to each proportional control valve is calculated based on the compensation coefficient, and each proportional control valve is adjusted accordingly; the target opening is the product of the compensation coefficient and the reference opening of the corresponding proportional control valve.

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