Tractor air conditioning system

Abstract

The utility model relates to the field of transport engineering, namely to systems for cooling and heating vehicle cabins, and can be used primarily in air conditioning systems for tractor cabins and other transport and technological machines. The air conditioning unit includes an air processing unit (1) containing a fan (3) mounted in a box-shaped housing (2) and driven by an electric motor (9), an internal heat exchanger (4) connected to a liquid cooling system of an internal combustion engine, and an evaporator heat exchanger (5) located in a circulation circuit together with a compressor (19) controlled by a controller (31), temperature sensors (24) and (25) inside the tractor cabin and outside air, and a microcontroller (26) containing a PID controller.The inputs of the microcontroller (26) are connected to the temperature sensor (24) inside the tractor cabin and to the temperature sensor (25) of the outside air, and the outputs are connected, through field-effect transistors (27), (28) and (29) installed in the electrical circuit, to the electric motor (9) of the fan (3), to the electric motor (16) of the servo drive installed at the input of the internal heat exchanger (4) of the ball valve (14) and to the electric motor (16) of the servo drive installed at the output of the internal heat exchanger (4) of the ball valve (14), respectively, and through the control relay (30) installed in the electrical circuit, to the input of the controller (31) controlling the inverter-type compressor (19). A stable temperature regime is achieved in the tractor cabin. 3 sec. fil.; 5 fig.

Description

[0001] The utility model relates to the field of transport engineering, namely to cooling and heating systems for vehicle cabins, and can be used primarily in air conditioning systems for tractor cabins and other transport and technological machines.

[0002] In today's global economic climate, increasing the productivity of transport and technological vehicle operators is a pressing issue. Unfavorable working conditions in the transport and technological vehicle workplace are the main cause of decreased productivity, rapid fatigue, occupational illnesses, and employee turnover among operators. Creating a favorable microclimate in the transport and technological vehicle cabin is one of the most important tasks in ensuring optimal working conditions for operators.Since one of the most significant factors influencing climate indicators is the temperature regime, the creation of a favorable microclimate in the cabin of a transport and technological vehicle is achieved through the development and use of air conditioning systems in it, ensuring the ability to automatically maintain a comfortable mode in the cabin with adaptive adjustment of the climate control system parameters to changing environmental conditions.

[0003] There are many known technical solutions dedicated to the development and use of automatic climate control systems for maintaining a comfortable mode in the vehicle cabin (RU Patent No. 2236956, cl. B60N1 / 06, 2003; PM Patent No. 61200, cl. B60N 1 / 00, 2005; PM Patent No. 21462, cl. G05D27 / 02, F24F5 / 00, B60R27 / 00, 2001). At the same time, the scope of application and design features of the climate control system itself predetermine the design and operating algorithm of the control device.

[0004] A climate control system for a vehicle, in particular a tractor, is known (RU Patent No. 2782205, Class B60N1 / 00, 2022). The climate control system includes an air handling unit containing a fan mounted in a box-shaped casing, driven by an electric motor, an internal heat exchanger connected to the liquid cooling system of the internal combustion engine, and an evaporator heat exchanger located in a circulation circuit together with a compressor. The box-shaped casing is made with two identical air ducts with inlet windows located symmetrically relative to the longitudinal axis of its symmetry and a fan impeller mounted in each air duct on an axis perpendicular to the axis of symmetry of the box-shaped casing. The front end wall of the box-shaped casing is made flat with an outlet window in the form of a slit with the center located in the geometric center of the front end wall.The internal heat exchanger and the evaporator heat exchanger are installed in a box-shaped housing in series and perpendicular to the longitudinal axis of its symmetry, and the circulation circuit of the air conditioning system is made with an inverter-type compressor controlled by a controller.

[0005] Overall control of the air conditioning system with an inverter compressor is performed by a controller, which is electrically connected to the compressor, condenser, dehumidifier, and electric motor driving the fan. The air temperature in the tractor cab, as well as the fan speed, which draws air from the tractor cab through the internal heat exchanger and the evaporator heat exchanger, are set manually. An automatic control system, based on electrical devices—an air temperature controller and a fan speed controller—monitors and maintains the air temperature in the tractor cab and the airflow rate from the tractor cab to the air handling unit. The speed of the working mechanism in the compressor compression chamber is set by the controller.When the set temperature in the tractor cab is reached, the compressor output remains at the level required to maintain the set temperature in the tractor cab. As the temperature in the tractor cab changes, the air conditioning system output automatically adjusts by adjusting the compressor output. With this air conditioning system, the air temperature in the tractor cab is regulated by adjusting the compressor output.

[0006] The low dynamics of comfort creation by this air conditioning system, caused directly by the design of the automatic temperature control system in the tractor cabin, which reacts only to changes in its current values ​​​​without predicting its change in the subsequent period of time, which affects the speed and performance of the air conditioning system as a whole, is eliminated in the technical solution protected by patent PM No. 240674, class B60N1 / 00, 2025, which is adopted as a prototype.

[0007] The air conditioning system (patent for PM No. 240674, prototype) includes an air handling unit containing a fan mounted in a box-shaped housing and driven by an electric motor, an internal heat exchanger connected to the liquid cooling system of the internal combustion engine, and an evaporator heat exchanger located in a circulation circuit together with a compressor controlled by a controller, temperature sensors for the inside of the tractor cabin and the outside air, and a microcontroller. The inputs of the microcontroller are connected to the temperature sensor inside the tractor cabin and the outside air temperature sensor, and the outputs are connected through a field-effect transistor installed in the electrical circuit to the fan electric motor and through a control relay installed in the electrical circuit to the input of the controller controlling the inverter-type compressor.The internal heat exchanger is connected to the liquid cooling system of the internal combustion engine by means of hoses and is designed with the possibility of disconnecting it from the liquid cooling system of the internal combustion engine by means of two identical taps, one of which is installed at the inlet of the internal heat exchanger, the other at its outlet.

[0008] A drawback of the existing air conditioning system is the instability of the temperature regime in the tractor cab, manifested by air temperature fluctuations caused by overshoot and delays in the microcontroller's control actions on the actuators. Despite the presence of predictive elements in the control unit, the actuators are controlled based on a limited set of parameters, primarily characterizing the current and previous temperature values, without taking into account the dynamic characteristics of the temperature change process. This does not fully prevent temperature fluctuations in the tractor cab. Fan impeller speed control is performed in a stepwise manner depending on the temperature range, which leads to abrupt changes in airflow intensity and further contributes to temperature fluctuations in the tractor cab.Furthermore, the internal heat exchanger, connected to the internal combustion engine's liquid cooling system and installed within the air handling unit's box-shaped housing, is controlled manually using valves installed at the internal heat exchanger's inlet and outlet. Manual control of the internal heat exchanger does not ensure coordinated operation of the air conditioning system components under changing operating conditions.

[0009] The lack of automatic shutdown of the internal heat exchanger from the liquid cooling system of the internal combustion engine during certain climatic periods of its operation, as well as the operating algorithm of the microcontroller, for the implementation of which a limited set of parameters characterizing the current and previous temperature value is sufficient without taking into account the dynamic characteristics of the process of its change, lead to a decrease in the accuracy of air temperature regulation in the tractor cab, resulting in significant temperature fluctuations in it and deterioration of the operator's working conditions.

[0010] The problem solved by the utility model is to increase the accuracy of air temperature regulation in the tractor cabin.

[0011] The technical result of solving the problem is to create a stable temperature regime in the tractor cabin by reducing temperature fluctuations in it, which is the key to the successful implementation of the technological process by the operator with high labor productivity.

[0012] The problem posed by the utility model is solved in that in the air conditioning system of a tractor, comprising an air processing unit including a fan installed in a box-shaped housing, driven by an electric motor, an internal heat exchanger connected to a liquid cooling system of an internal combustion engine and equipped with two identical taps, one of which is installed at the inlet of the internal heat exchanger, the other at its outlet, and an evaporator heat exchanger located in a circulation circuit together with an inverter-type compressor controlled by a controller, temperature sensors inside the tractor cabin and outside air and a microcontroller, wherein the inputs of the microcontroller are connected to the temperature sensor inside the tractor cabin and the outside air temperature sensor, and the outputs are connected through a field-effect transistor installed in the electrical circuit to the fan electric motor and through a control relay installed in the electrical circuit to the input of the controller,The inverter-type compressor control unit uses straight-through ball valves with a servo drive, and the microcontroller contains a PID controller and two additional outputs, one of which is connected to the electric motor of the servo drive installed at the input of the internal heat exchanger of the ball valve via a field-effect transistor installed in the electrical circuit, the other is connected to the electric motor of the servo drive installed at the output of the internal heat exchanger of the ball valve via a field-effect transistor installed in the electrical circuit.

[0013] In the preferred embodiment, the tractor's climate control system uses an ATmega 328 microcontroller, electronic ds18b20 temperature sensors inside the tractor cabin and outside air, and straight-through ball valves with an NG-EL 12 DC servo drive.

[0014] The development of the new air conditioning system design took into account the specific work of a transport and technological vehicle operator, who is tasked with completing a specific technological task and who is particularly demanding of a stable temperature regime in the vehicle's cabin. A stable temperature regime in the vehicle's cabin is achieved through precise air temperature control.

[0015] The developed control algorithm and design of the control unit of the air conditioning system of the tractor, providing for the control of not only the fan, but also the straight-through ball valves with a servo drive (hereinafter referred to as ball valves), installed respectively at the inlet and outlet of the internal heat exchanger, and allowing the internal heat exchanger to be automatically disconnected from the liquid cooling system of the internal combustion engine during certain climatic periods of operation, ensure the accuracy of air temperature regulation in the tractor cab, which helps to create a stable temperature regime in it.

[0016] Electric valves are known to be shut-off and control devices designed for remote control of liquid and gaseous media flows. Unlike manual valves, these valves automatically open and close the valve in response to a control signal from the automation system. The main purpose of this equipment is to control technological processes without operator intervention, which is especially important when working with aggressive, hot, or pressurized media. An electric drive allows the valve to be integrated into an automated process control system for engineering systems. Electric ball valves have become widely used due to their precise control, remote control capability, and compatibility with industrial controllers [https: / / evelen.ru / catalog / zaporno_reguliruyushchaya_armatura / krany_s_elektroprivodom / (accessed 13.04.2025)].

[0017] It is also known that a servo drive (from the Latin servus - "servant, assistant, slave") is an electromechanical system for precisely controlling the motion parameters (position, speed, acceleration) of an actuator. It is also known as a tracking drive (ru.wikipedia.org*inner.suznanierussia.ru). Unlike standard drives, servo drives provide high positioning accuracy and operational stability thanks to a built-in feedback system that continuously monitors the actual position and adjusts the control action (inner.su). Due to their high accuracy, reliability, and automation, servo drives have become the standard for modern engineering systems. They simplify control, increase energy efficiency, and make it possible to maintain precise parameters without human intervention.

[0018] [https: / / evelen.ru / catalog / zaporno_reguliruyushcha_armatura / krany_s_elektroprivodom / (access date 04 / 13 / 2025)].

[0019] Taking into account the above, in order to automatically disconnect the internal heat exchanger from the liquid cooling system of the internal combustion engine, the declared air conditioning system of the tractor uses flow-type ball valves with servo drives.

[0020] The use of two ball valves, one installed at the inlet of the internal heat exchanger and the other at its outlet, is necessary to ensure complete and prompt disconnection of the heat exchanger from the internal combustion engine's liquid cooling system, eliminating its influence on the air temperature in the tractor cab, especially in conditions requiring intensive air cooling for precise temperature control in the tractor cab. Using a single valve does not completely stop coolant circulation through the internal heat exchanger, since residual pressure and possible natural fluid circulation in the internal combustion engine's cooling system can cause partial coolant flow, resulting in unwanted heat transfer to the tractor cab.

[0021] It is also known that the PID controller is a software algorithm running on a microcontroller, which acts as the central element of a closed-loop control system, or a feedback control loop [https: / / kedrsolutions.ru / blog / pid-regulyatory-principy-raboty (date accessed 04 / 13 / 2025)].

[0022] The PID algorithm regulates a time-varying process variable by calculating a control signal, which is the sum of three components: proportional, integral, and differential. Hence the name. General-purpose PID controllers are used to return the controlled variable to an acceptable range, maintain this value at a specified level, and quickly respond to deviations. In some cases, using only a P or PI controller is sufficient. However, when greater stability or a degree of robustness is required, which requires eliminating unwanted overshoot, a PID controller is used. Since the PID controller works only with numbers, it can be applied to virtually any process. Although the PID algorithm has been used for over 70 years, it remains the most common solution in virtually every industry.The use of PID controllers for temperature control in the metallurgical industry is of particular importance, since heat treatment of metals often requires high precision [https: / / kedrsolutions.ru / blog / pid-regulyatory-principy-raboty (date accessed 13.04.2025)].

[0023] Considering the above, the proposed technical solution implemented a PID algorithm on the air conditioning system microcontroller. Its purpose was to control the fan impeller speed and the position of the ball valve. This solution enabled smooth starting and stopping of the fan impeller, complete and prompt disconnection of the internal heat exchanger via ball valves from the internal combustion engine's liquid cooling system, eliminating its influence on the air temperature in the tractor cab, and eliminating unwanted overshoot. As a result, high stability and consistent temperature control in the tractor cab were achieved.

[0024] The utility model is illustrated by drawings.

[0025] Fig. 1 shows a basic diagram of the air conditioning system; Fig. 2 shows an air processing unit, front view; Fig. 3 is the same, section along A-A in Fig. 2; Fig. 4 shows a straight-through ball valve with a servo drive; Fig. 5 shows a basic diagram of the control unit of the air conditioning system of the tractor (item 34 in Fig. 1), including a microcontroller 26, field-effect transistors 27, 28 and 29, a control relay 30 and a controller 31.

[0026] The air conditioning system of the tractor includes an air processing unit 1 installed in the tractor cab under the instrument panel, which contains a fan 3, an internal heat exchanger 4 and an evaporator heat exchanger 5 installed in a box-shaped housing 2.

[0027] The rear end wall of the box-shaped casing 2 is provided with two identical air ducts 6 with inlet windows 7, located symmetrically relative to the longitudinal axis of its symmetry. In each air duct 6, on an axis 8 perpendicular to the axis of symmetry of the box-shaped casing 2, an impeller of a fan 3 is installed. An electric motor 9, driving the impeller of the fan 3, is fixed on the box-shaped casing 2 between the air ducts 6 along its axis of symmetry (not shown). By means of the impeller of the fan 3, the air from the tractor cabin is uniformly forced into the box-shaped housing 2 through the inlet windows 7. The front end wall 10 of the box-shaped housing 2 is made flat and is provided with an outlet window 11 in the form of a slit with a center located in the geometric center of the front flat end wall 10. In this case, the area of ​​the outlet window S is related to the area of ​​the front flat end wall as 1:7.5 and is 5157 mm in the preferred embodiment. 2And the ratio of the total area of ​​the inlet ports 7 to the area of ​​the outlet port 11 is 2:1.

[0028] The internal heat exchanger 4 and the evaporator heat exchanger 5 are installed in the box-shaped housing 2 in series and perpendicular to the longitudinal axis of its symmetry. Internal heat exchanger 4 is connected to the liquid cooling system of the internal combustion engine 13 via hoses 12, serves to heat the air in the tractor cab and is designed with the possibility of disconnecting it from the liquid cooling system of the internal combustion engine by means of two identical ball valves 14, one of which is installed at the inlet of internal heat exchanger 4, the other - at its outlet. The claimed technical solution uses industrially produced straight-through ball valves with a NG-EL 12 DC servo drive.

[0029] The operating principle of ball valve 14 is based on the rotational movement of ball valve 15 (Fig. 4). After a control signal is applied, electric motor 16, via gearbox 17 and shaft 18, rotates ball valve 15 by 90°, changing the flow direction. In the "open" position, the axial bore (not shown) of ball valve 15 aligns with the direction of hose 12, ensuring free passage of the medium. A quarter-turn rotation closes the flow section of hose 12, blocking the flow.

[0030] Evaporator heat exchanger 5 is designed to cool the air in the tractor cab. Compressor 19, condenser 20, dehydrator 21, thermostatic valve 22, and evaporator heat exchanger 5 are connected by copper pipes 23 and form a circulation circuit within which a mixture of R134a freon and a small amount of compressor oil (hereinafter referred to as freon) circulates. The air conditioning system design utilizes an inverter-type compressor 19 with an electric drive (hereinafter referred to as the compressor).

[0031] The air conditioning system is equipped with an electronic temperature sensor 24, installed inside the tractor cab, and an electronic outside air temperature sensor 25, installed on the outside of the tractor cab. The proposed technical solution utilizes commercially available DS18B20 electronic temperature sensors.

[0032] The speed of rotation of the impeller of the fan 3 and the position of the ball valve 15 of the ball valve are controlled by the ATmega 328 microcontroller containing a PID controller (hereinafter referred to as the microcontroller 26), the inputs of which are intended to connect the temperature sensors 24 and 25 inside the tractor cabin and the outside air, respectively, and the outputs - through the field-effect transistor 27 to the electric motor 9 of the fan 3, through the field-effect transistor 28 to the electric motor 16 of the servo drive of the ball valve 14 installed at the input of the internal heat exchanger 4, through the field-effect transistor 29 to the electric motor 16 of the servo drive of another ball valve 14 installed at the output of the internal heat exchanger 4, and through the control relay 30 - to the input of the controller 31, which controls the compressor 19 installed in the circulation circuit of the air conditioning system. In this case, The outputs of controller 31 are connected to compressor 19, condenser 20 and dryer 21 installed in series in the circulation circuit.Power supply to microcontroller 26 is provided through step-down voltage stabilizer 32 via electrical wires 33.

[0033] Microcontroller 26, field-effect transistors 27, 28 and 29, as well as control relay 30 and controller 31 are installed in a common housing and represent the control unit of the air conditioning system of the tractor 34 (Fig. 1).

[0034] The tractor's climate control system operates as follows.

[0035] The tractor's air conditioning system operation algorithm includes two stages: the first stage lasts 3 minutes; the second stage continues from the third minute of its operation.

[0036] The operator, through the step-down voltage stabilizer 32 and by means of electrical wires 33, connects the microcontroller 26, the electric motor 9 of the fan 3 and each electric motor 16 of the servo drive of each ball valve 14 to the power supply from the on-board network.

[0037] Microcontroller 26 polls temperature sensors 24 and 25 inside the tractor cabin and outside air every minute. The data received from temperature sensors 24 and 25 are stored in the memory of microcontroller 26. At the same time, microcontroller 26 closes the contacts of control relay 30 and, using field-effect transistor 27, sets the maximum rotation speed of impeller 3, which is 3800 rpm (this value depends on the type of fan; in this specific example, it is 3800 rpm), and, using field-effect transistors 28 and 29, opens or closes ball valve 15 of each ball valve 14, depending on the readings of sensor 24 inside tractor cabin. Ball valve 15 of each valve 14 is open if the temperature in the tractor cabin is below 22°C, and closed if the temperature in the tractor cabin is above 22°C.

[0038] The signal about the closure of the contacts of the control relay 30 is sent to the controller 31, which starts the compressor 19 at maximum capacity in order to quickly establish the required temperature in the tractor cabin. At the same time, air is uniformly sucked from the interior of the tractor cabin through the inlet windows 7 of the air ducts 6 by means of the rotating impellers of the fan 3. This air, passing through the internal heat exchanger 4, is heated by taking the amount of heat from the coolant circulating in the liquid cooling system of the internal combustion engine 13 and entering the internal heat exchanger 4 through the hose 12. For cooling, the heated air passes through the heat exchanger of the evaporator 5, where it is cooled to the set temperature and enters the tractor cabin through the outlet window 11.

[0039] Gaseous freon enters compressor 19 from evaporator heat exchanger 5 at a low pressure of 3-5 atmospheres and a temperature of 10-20°C. In compressor 19, freon is compressed to a pressure of 15-25 atmospheres, resulting in freon heating to 70-90°C and entering condenser heat exchanger 20, which is blown with air at a temperature lower than the freon temperature. As a result, the freon cools and transitions from the gaseous phase to the liquid phase, releasing additional heat. At the same time, the air passing through condenser 20 is heated. At the outlet of condenser 20, freon is in a liquid state under high pressure, the freon temperature is 10-20°C higher than the air temperature in the tractor cab. From the condenser 20, warm freon passes through the dryer 21 into the thermostatic valve 22, as a result of passing through which the freon pressure decreases to 3-5 atmospheres and the freon cools down.Next, a mixture of liquid and gaseous freon at low pressure and low temperature enters the evaporator heat exchanger 5, which is blown by air entering through inlet ports 7 from the tractor cab. In the evaporator heat exchanger 5, the freon completely converts to a gaseous state, absorbing heat from the air entering the box-shaped housing 2 of the air handling unit 1, cooling it. The low-pressure gaseous freon then enters the inlet of compressor 19, and the entire circulation cycle is repeated. This operating mode of the air conditioning system is typical for the first three minutes of operation and thereafter when the contacts of control relay 30 are closed.

[0040] In the second stage, microcontroller 26, based on the received data on the air temperature inside the tractor cab over the previous three minutes of air conditioning operation, initiates a hybrid control algorithm based on a PID controller and an adaptive algorithm. The PID controller is responsible for controlling the ball valve 15 of each ball valve 14 and the impeller of fan 3 if the air temperature is either below 21°C or above 23°C; the adaptive algorithm is responsible for controlling the ball valve 15 of each ball valve 14 and the impeller of fan 3 in the temperature range of 21…23°C.

[0041] The formation of the PID controller control signal is carried out according to the generally accepted formula:

[0042]

[0043] where u(t) is the output signal (units of measurement depending on the signal);

[0044] K p , K i , K d - proportional, integral and differential coefficients, respectively;

[0045] e(t) - control error.

[0046] The control signal from the adaptive algorithm is generated based on the analysis of the predicted rate of change of temperature Y пр .

[0047] To determine the predicted rate of change of temperature Y пр the formula is applied:

[0048]

[0049] where Y(t) is the rate of temperature change, °C / min;

[0050] X(t) - acceleration of temperature change, °C / min 2 ;

[0051] Δt - time between measurements, min.

[0052] If Y пр (t+Δt)>0, then X(t) is analyzed:

[0053] - at 0 <X(t)<1 управляющий сигнал u a from controller 31 for electric motor 16 of the servo drive of each ball valve 14 and electric motor 9 of fan 3 is formed according to the formula:

[0054]

[0055] - when X(t)≥1, the control signal u ais 100%, the ball valve 15 of each ball valve 14 completely closes the flow section of the hose 12, the control relay 30 closes, and the speed of the electric motor 9 of the fan 3 is set to maximum.

[0056] Provided that Y np (t+Δt)<0, X(t) is also analyzed:

[0057] - when 0<|X|(t)<1 control signal u a from controller 31 for electric motor 16 of the servo drive of each ball valve 14 and electric motor 9 of fan 3 is formed according to the formula:

[0058]

[0059] - when |X|(t)≥1 the control signal u a from controller 31 is 100%, ball valve 15 of each ball valve 14 completely opens the flow section of hose 12, control relay 30 opens, and the speed of electric motor 9 of fan 3 is set to maximum.

[0060] Thanks to this operating algorithm, the microcontroller 26 of the air conditioning system is able to ensure high accuracy of air temperature regulation in the tractor cabin, resulting in a reduction in temperature fluctuations in it, which underlies the creation of a stable temperature regime in the tractor cabin and is the key to the successful implementation of the technological process by the operator with high labor productivity.

[0061] The declared air conditioning system is industrially applicable.

[0062] To conduct experimental studies, the authors developed a laboratory setup based on the cabin of a HTZ T-150K tractor and equipped with the stated air conditioning system. Temperatures in the tractor cabin and outside air were measured using DS18B20 temperature sensors 24 and 25, respectively. Signals from sensors 24 and 25 were sent to ATmega 328 microcontroller 19, where they were processed. Control was sent to electric motor 9 of fan 3 of the air handling unit, to electric motor 16 of the servo drive of each ball valve 14, and to Arduino Nano controller 31, which controls inverter-type compressor 19 located in the air conditioning system's circulation circuit.

[0063] Experimental data from field testing of the declared air conditioning system showed that:

[0064] 1) The stability of the temperature regime in the tractor cabin with the declared air conditioning system installed in it is much higher compared to the prototype air conditioning system; the time the operator spends in the optimal temperature regime in the tractor cabin increased from 33% to 50% of the total working time;

[0065] 2) the average value of the standard deviation of the air temperature in the cabin of the HTZ T-150K tractor during comparative tests of the prototype and the declared air conditioning system was 0.79°C and 0.32°C, respectively, which indicates an increase in the stability of the temperature regime by 60%;

[0066] 3) The stability of the temperature regime in the tractor cabin with the declared air conditioning system installed in it is much higher compared to the prototype air conditioning system, which made it possible to increase the productivity of the tractor operator by 15%.

[0067] Thus, the technical result has been confirmed, which consists in creating a stable temperature regime in the tractor cabin, which is the key to the operator’s successful implementation of the technological process with high labor productivity.

[0068] The declared air conditioning system can be recommended for installation in the cabin of a tractor and other transport and technological machines.

Claims

1. A tractor climate control system comprising an air handling unit including a fan installed in a box-shaped housing and driven by an electric motor, an internal heat exchanger connected to a liquid cooling system of an internal combustion engine and provided with two identical taps, one of which is installed at the inlet of the internal heat exchanger, the other at its outlet, and an evaporator heat exchanger located in a circulation circuit together with an inverter-type compressor controlled by a controller, temperature sensors inside the tractor cabin and outside air, and a microcontroller, the inputs of which are connected to a temperature sensor inside the tractor cabin and an outside air temperature sensor, and the outputs - through a field-effect transistor installed in an electrical circuit to the fan electric motor and through a control relay installed in an electrical circuit, to the input of a controller controlling an inverter-type compressor, characterized in that,that straight-through ball valves with a servo drive are used, and the microcontroller contains a PID controller and two additional outputs, one of which is connected via a field-effect transistor installed in the electrical circuit to the electric motor of the servo drive installed at the input of the internal heat exchanger of the ball valve, the other output of the microcontroller via a field-effect transistor installed in the electrical circuit is connected to the electric motor of the servo drive installed at the output of the internal heat exchanger of the ball valve.

2. The climate control system according to paragraph 1, characterized in that an ATmega 328 microcontroller is used.

3. The climate control system according to paragraph 1, characterized in that electronic sensors of the DS18B20 type are used for the temperature inside the tractor cabin and for the outside air.

4. The air conditioning system according to paragraph 1, characterized in that straight-through ball valves with an NG-EL 12 DC servo drive are used.

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