Air conditioning system for construction machinery and equipment

Abstract

This disclosure provides an air conditioning system for engineering machinery. The air conditioning system includes a cooling circuit and a bypass branch. The cooling circuit includes a compressor, a condenser, a throttling and pressure-reducing device, and an evaporator, which are sequentially connected and form a loop. The bypass branch includes a first bypass control valve and a second bypass control valve. One end of the first bypass control valve is connected between the exhaust port of the compressor and the condenser, and the other end of the first bypass control valve is connected to one end of the second bypass control valve. The other end of the second bypass control valve is connected to the inlet of the evaporator. The first bypass control valve is a normally closed solenoid valve, and the second bypass control valve is a hot gas bypass valve. The air conditioning system provided by this disclosure can reduce the start-stop frequency of the compressor and reduce the wear of internal compressor components.

Description

Technical Field

[0001] This disclosure relates to the field of thermal management, and in particular to an air conditioning system for engineering machinery. Background Technology

[0002] Construction machinery and equipment (such as trucks, electric shovels, excavators, etc.) are used in fields such as construction and mining. They need to work for long periods of time, so the cooling requirements in the cab are relatively high.

[0003] In related technologies, the air conditioning system of construction machinery includes a compressor, condenser, and evaporator. When cooling the cab, the compressor operates, compressing the refrigerant into a high-temperature, high-pressure gaseous state. This high-temperature, high-pressure gaseous refrigerant then passes through the condenser and becomes a high-pressure liquid. The high-pressure liquid refrigerant enters the evaporator and exchanges heat with it, absorbing heat and cooling the cab, thus becoming a low-temperature, low-pressure gaseous refrigerant. This low-temperature, low-pressure gaseous refrigerant then returns to the compressor for compression, thus completing the cycle.

[0004] However, due to the limited space in the cab of construction machinery, typically only 3 to 6 meters... 3 The poor insulation of the air conditioning system means that changes in external temperature can rapidly affect the internal temperature of the cabin, causing significant fluctuations in the system's heat load and resulting in the compressor constantly starting and stopping. This constant starting and stopping of the compressor subjects internal components (such as bearings, pistons, and valves) to substantial inrush currents and mechanical stress, accelerating wear. Furthermore, frequent compressor starts and stops significantly increase power consumption, wasting energy. Utility Model Content

[0005] This disclosure provides an air conditioning system for engineering machinery, which can reduce the start-stop frequency of the compressor and decrease wear on internal compressor components. The technical solution is as follows:

[0006] This disclosure provides an air conditioning system for engineering machinery equipment. The air conditioning system includes a cooling circuit and a bypass branch. The cooling circuit includes a compressor, a condenser, a throttling and pressure-reducing device, and an evaporator that are connected in sequence to form a circuit. The bypass branch includes a first bypass control valve and a second bypass control valve. One end of the first bypass control valve is connected between the exhaust port of the compressor and the condenser, and the other end of the first bypass control valve is connected to one end of the second bypass control valve. The other end of the second bypass control valve is connected to the inlet of the evaporator. The first bypass control valve is a normally closed solenoid valve, and the second bypass control valve is a hot gas bypass valve.

[0007] In another implementation of this disclosure, the second bypass control valve is a mechanical pressure valve.

[0008] In another implementation of this disclosure, the cooling circuit further includes a high-pressure switch and / or a low-pressure switch, the high-pressure switch being connected to the exhaust port of the compressor; and the low-pressure switch being connected to the passage between the evaporator and the compressor.

[0009] In another implementation of this disclosure, the air conditioning system further includes a controller, which is electrically connected to the high-pressure switch, the first bypass control valve, and the low-pressure switch, respectively.

[0010] In another implementation of this disclosure, the evaporator includes an evaporation shell, an evaporation core, an electric heating element, a fresh air module, and an evaporation fan. The evaporation core, the electric heating element, and the evaporation fan are all located in the evaporation shell. The fresh air module is located outside the evaporation shell and is connected to the evaporation shell. The fresh air module has a fresh air channel inside, which communicates with both the interior and exterior of the evaporation shell.

[0011] In another implementation of this disclosure, the fresh air module includes a blower and an air filter, the air filter being located at the air inlet of the blower and connected to the blower, and the outlet of the blower communicating with the interior of the evaporator housing.

[0012] In another implementation of this disclosure, the cooling circuit further includes a first control valve, the two ends of which are connected to the condenser and the throttling and pressure-reducing device, respectively; when the compressor starts, the first control valve is in an open state, and when the compressor stops, the first control valve is in a closed state.

[0013] In another implementation of this disclosure, the cooling circuit further includes a second control valve, a dryer, and a third control valve, wherein the second control valve, the dryer, and the third control valve are connected in series between the first control valve and the condenser, the two ends of the second control valve are respectively connected to the outlet of the condenser and one end of the dryer, and the third control valve is respectively connected to one end of the first control valve and the other end of the dryer.

[0014] In another implementation of this disclosure, the condenser includes a condenser housing, a condenser core, and a condenser fan. The condenser core is embedded in one side wall of the condenser housing and connected to the condenser housing. The condenser fan is located in the condenser housing and connected to the condenser housing. The first bypass control valve, the second bypass control valve, the high-pressure switch, the compressor, the low-pressure switch, the first control valve, the second control valve, the dryer, and the third control valve are all located in the condenser housing and are respectively connected to the condenser housing.

[0015] In another implementation of this disclosure, the refrigerant in the compressor is R410a refrigerant.

[0016] The beneficial effects of the technical solutions provided in this disclosure are:

[0017] Because the air conditioning system includes a bypass branch, and the bypass branch is equipped with a first bypass control valve, when the cooling circuit is cooling, after the first bypass control valve and the second bypass control valve are opened, part of the refrigerant compressed by the compressor enters the evaporator through the first bypass control valve, realizing the hot gas bypass function, regulating the system's cooling capacity, avoiding frequent start-stop of the compressor under low load, reducing wear on the internal components of the compressor, and improving energy efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram illustrating the working principle of an air conditioning system for engineering machinery provided in this embodiment of the present disclosure;

[0020] Figure 2 This is a schematic diagram of the evaporator structure;

[0021] Figure 3 for Figure 2 Exploded view;

[0022] Figure 4 This is a schematic diagram of the condenser structure;

[0023] Figure 5 for Figure 4 Exploded view.

[0024] The symbols in the diagram represent the following meanings:

[0025] 1. Cooling circuit; 10. High-pressure switch; 11. Compressor; 12. Condenser; 121. Condenser shell; 122. Condenser core; 123. Condenser fan; 13. Throttling and pressure reduction device; 14. Evaporator; 141. Evaporator shell; 142. Evaporator core; 143. Electric heating element; 144. Fresh air module; 1440. Fresh air duct; 1441. Blower; 1442. Air filter; 145. Evaporator fan; 15. Low-pressure switch; 16. First control valve; 17. Second control valve; 18. Dryer; 19. Third control valve; 110. Night vision goggles; 111. Liquid receiver;

[0026] 2. Bypass branch; 21. First bypass control valve; 22. Second bypass control valve. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0028] This disclosure provides an air conditioning system for engineering machinery equipment, such as... Figure 1 As shown, the air conditioning system includes a cooling circuit 1 and a bypass branch 2. The cooling circuit 1 includes a compressor 11, a condenser 12, a throttling and pressure reducing device 13 and an evaporator 14 that are connected in sequence to form a circuit.

[0029] The bypass branch 2 includes a first bypass control valve 21 and a second bypass control valve 22. One end of the first bypass control valve 21 is connected between the exhaust port of the compressor 11 and the condenser 12. The other end of the first bypass control valve 21 is connected to one end of the second bypass control valve 22. The other end of the second bypass control valve 22 is connected to the inlet of the evaporator 14.

[0030] The first bypass control valve 21 is a normally closed solenoid valve, and the second bypass control valve 22 is a hot gas bypass valve.

[0031] When the air conditioning system provided in this embodiment is used in construction machinery, such as an electric shovel, since the air conditioning system includes a cooling circuit 1 and a bypass branch 2, when the cab of the construction machinery is cooled through the cooling circuit 1, the refrigerant is compressed by the compressor 11 and becomes a high-temperature, high-pressure gaseous state, which enters the condenser 12. The vaporized refrigerant exchanges heat with the ambient air and undergoes a phase change under the action of the condenser 12, becoming a high-pressure liquid. The high-pressure liquid refrigerant flows through the throttling and pressure-reducing device 13 and enters the evaporator 14. Under the action of the evaporator 14, it exchanges heat and absorbs a large amount of heat to cool the cab. At the same time, it becomes a low-temperature, low-pressure gaseous state, and the low-temperature, low-pressure gaseous refrigerant returns to the compressor 11 to form a cycle.

[0032] Meanwhile, since the air conditioning system also includes a bypass branch 2, which is equipped with a first bypass control valve 21 and a second bypass control valve 22, the first and second bypass control valves 21 and 22 can be opened when the cooling circuit 1 is cooling. A portion of the refrigerant compressed by the compressor 11 enters the evaporator 14 through the first bypass control valve 21, achieving hot gas bypass function, regulating the system's cooling capacity, avoiding frequent start-stop of the compressor 11 under low load, and improving system reliability. For example, in actual use, when the first and second bypass control valves 21 and 22 are closed, all the refrigerant flows through the cooling circuit 1 for a normal cooling cycle (condensation → expansion → evaporation), maximizing the cooling capacity. When the first bypass control valve 21 is opened, a portion of the refrigerant, after high-temperature and high-pressure vaporization, enters the evaporator 14, reducing the effective cooling capacity. Simultaneously, the temperature of the evaporator 14 rises, preventing over-cooling or icing.

[0033] Furthermore, by cooperating with the first bypass control valve 21 and the second bypass control valve 22, the flow rate of refrigerant entering the inlet of the evaporator 14 can be adjusted. Therefore, the flow rate of hot gas from the discharge port of the compressor 11 to the inlet of the evaporator 14 can be dynamically controlled according to system requirements (such as evaporator temperature and pressure), thereby avoiding frequent start-stop of the compressor 11 under low load, improving system reliability, reducing wear of internal components of the compressor 11, and improving energy efficiency.

[0034] Furthermore, the first bypass control valve 21 is configured as a normally closed solenoid valve. This allows the first bypass control valve 21 to function as a switch, cutting off or opening the bypass branch based on signals (such as temperature and pressure). Moreover, in conjunction with the hot gas bypass valve, it enables more flexible flow control. For example, if a door is suddenly opened, causing hot air to rush into the cab, the first bypass control valve 21 can instantly open the bypass to prevent the compressor 11 from being overloaded.

[0035] In this embodiment, the opening and closing of the first bypass control valve 21 is controlled based on the feedback signal from the icing temperature sensor and the air conditioning set temperature. When the heat load of the evaporator 14 is low, the evaporation pressure drops. When the outlet air temperature is lower than the temperature set by the icing temperature sensor, the controller sends a signal to open the first bypass control valve 21. The hot gas bypass valve bypasses a certain amount of gaseous high-temperature refrigerant to the evaporator core, increasing the evaporation pressure and preventing the evaporator 14 from icing. This design uses the signal from the icing temperature sensor to control the opening and closing of the first bypass control valve 21 to adjust the system pressure, instead of using the compressor shutdown for system protection. This avoids the possibility that the large-displacement compressor cannot start frequently, leading to poor compressor oil return. Moreover, according to the different air conditioning set temperatures, the icing sensor connection temperature is compensated accordingly to achieve the temperature regulation effect.

[0036] By setting the second bypass control valve 22 as a hot gas bypass valve, the flow rate of hot gas from the compressor 11 exhaust port to the evaporator 14 inlet can be dynamically controlled according to system requirements (such as compressor discharge pressure, evaporator temperature, etc.), thereby avoiding frequent start-stop of compressor 11 under low load and improving system reliability.

[0037] Optionally, the second bypass control valve 22 may be a mechanical pressure type or an electric control type.

[0038] In this embodiment, the second bypass control valve 22 is a mechanical pressure type. The second bypass control valve 22 may include a temperature sensing bulb, valve body, bellows, valve core, valve seat, and spring, etc. The temperature sensing bulb is installed on the suction pipe of the compressor 11 and is filled with a temperature-sensing medium (such as refrigerant or inert gas) that matches the system refrigerant. The temperature sensing bulb can generate corresponding pressure or volume changes with the suction pressure of the compressor 11.

[0039] Both the bellows and the valve core are located within the valve body. One end of the bellows is fixed inside the valve body, and the other end is fixedly connected to the valve core. The expansion and contraction displacement of the bellows can be precisely transmitted to the valve core. A spring is fitted around the valve core, with its two ends abutting against the outer wall of the valve core and the inner wall of the valve body, respectively. The valve seat is an annular component located on the side of the valve core furthest from the bellows, and is fixedly connected to the valve body. When the valve core leaves the valve seat, the gap between them forms a bypass channel, the size of which determines the bypass flow rate; when the valve core is in contact with the valve seat, the valve is closed, blocking the flow.

[0040] The bellows is a telescopic tubular structure, with one end bearing the suction pressure from the temperature sensing bulb and the other end bearing the elastic force of the adjusting spring. Pressure changes cause deformation, which in turn moves the valve core.

[0041] When the compressor suction pressure is lower than the set value, the pressure of the temperature sensing bulb decreases. The "suction-side pressure" on the bellows is less than the elastic force of the adjusting spring. The spring pushes the bellows to contract, and the valve core moves in the opening direction (the valve core leaves the valve seat). High-pressure hot gas enters the low-pressure side through the bypass channel. When the suction pressure rises back to the set value, the pressure of the temperature sensing bulb increases. The bellows extends under pressure, overcoming the spring force and driving the valve core to move in the closing direction (the valve core contacts the valve seat), reducing or cutting off the bypass flow.

[0042] In other examples, the second bypass control valve 22 can also be electrically controlled. In this case, the controller in the air conditioning system can input the compressor suction side pressure seen by the pressure sensor and the evaporator temperature detected by the temperature sensor to the second bypass control valve 22. The second bypass control valve 22 automatically controls the opening size according to the received temperature and pressure. For example, when the temperature in the driver's cab is detected to be lower than the set temperature, it indicates that the cooling demand in the driver's cab is low and the cab is already cold enough. At this time, the second bypass control valve 22 can automatically adjust its opening size according to the monitored temperature, increasing it so that more high-temperature and high-pressure gas directly enters the evaporator 14, reducing the effective cooling capacity. The temperature of the evaporator 14 rises, preventing over-cooling or icing. When the temperature in the driver's cab is detected to be higher than the set temperature, the cooling demand in the driver's cab is high. The second bypass control valve 22 closes or decreases its opening size, and all or most of the refrigerant goes through the normal cycle (condensation → expansion → evaporation), maximizing the cooling capacity.

[0043] In this embodiment, the controller can also be electrically connected to the first bypass control valve 21. This facilitates intelligent control.

[0044] Optionally, the cooling circuit 1 also includes a high-pressure switch 10 and / or a low-pressure switch 15, with the high-pressure switch 10 connected to the exhaust port of the compressor 11 and the low-pressure switch 15 connected to the suction port of the compressor 11. The low-pressure switch 15 is connected in the passage between the evaporator 14 and the compressor 11. The controller is electrically connected to the high-pressure switch 10 and / or the low-pressure switch 15 respectively.

[0045] In the above implementation, the high-pressure switch 10 can monitor the system pressure. When the system pressure is too high, the high-pressure switch 10 activates, and the controller opens the first bypass control valve 21 to bypass the hot gas, ensuring that the system operates within a reasonable pressure range. For example, if the condenser 12 has poor heat dissipation (such as blockage or fan failure), the high-pressure switch 10 detects a sudden increase in the discharge pressure of the compressor 11. The high-pressure switch 10 activates, and the controller controls the first bypass control valve 21 to release some of the high-pressure gas, reducing the system pressure and preventing damage to the compressor 11.

[0046] The low-pressure switch 15 activates when the pressure at the compressor 11's suction port is too low. For example, when the cab temperature is close to the set value, the evaporator 14's heat load decreases, and the evaporation pressure drops. The low-pressure switch 15 detects that the low pressure is below the set threshold. After activation, the controller controls the first bypass control valve 21 to open, allowing some high-temperature, high-pressure gas (hot gas) to be directly introduced from the compressor 11's exhaust port into the evaporator 14's inlet. This increases the pressure inside the evaporator 14, preventing icing (increasing the evaporation temperature). Simultaneously, the cooling capacity decreases, preventing excessive cooling, while the compressor 11 continues to run (reducing start-stop losses). When the cab temperature is high and rapid cooling is needed, the evaporator 14's heat load is high, and the evaporation pressure (low-pressure side) is normal or slightly high. The low-pressure switch 15 detects that the low pressure is within a reasonable range. The controller controls the first bypass control valve 21 to close, allowing the refrigerant to circulate normally (condensation → throttling → evaporation). This maximizes cooling capacity and achieves rapid cooling.

[0047] For example, the throttling and pressure-reducing device 13 is an expansion valve. This reduces cost and space while allowing for direct control of flow and pressure by adjusting the valve needle opening, with a fast response time.

[0048] Optionally, the cooling circuit 1 further includes a first control valve 16, which is connected between the condenser 12 and the throttling and pressure-reducing device 13, with its two ends connected to the condenser 12 and the throttling and pressure-reducing device 13 respectively. When the compressor 11 starts, the first control valve 16 is in the open state, and when the compressor 11 stops, the first control valve 16 is in the closed state.

[0049] In the above implementation, a first control valve 16 is provided at the front end of the throttling and pressure reducing device 13. The first control valve 16 works synchronously with the compressor 11. In this way, when the compressor 11 is engaged, the first control valve 16 is turned on, becoming a refrigerant passage. After the compressor 11 stops, the first control valve 16 is de-energized, cutting off the refrigerant passage and preventing a large amount of liquid refrigerant from rushing into the evaporator 14. This avoids the compressor 11 from sucking in liquid refrigerant and damaging the compressor 11 if a large amount of refrigerant rushes into the evaporator 14 and is restarted.

[0050] In this embodiment, the first control valve 16 is a solenoid valve and is electrically connected to the controller. After the compressor 11 starts, the controller controls the first control valve 16 to be energized and opened. After the compressor 11 stops, the controller controls the first control valve 16 to be de-energized and closed.

[0051] Optionally, the cooling circuit 1 further includes a second control valve 17, a dryer 18, and a third control valve 19. The second control valve 17, the dryer 18, and the third control valve 19 are connected in series between the first control valve 16 and the condenser 12. The two ends of the second control valve 17 are respectively connected to the outlet of the condenser 12 and one end of the dryer 18, and the third control valve 19 is respectively connected to one end of the first control valve 16 and the other end of the dryer 18.

[0052] In the above implementation, the arrangement of the second control valve 17 and the third control valve 19 facilitates the replacement of the dryer 18 or the maintenance of the dryer. For example, after the dryer 18 has been maintained, the second control valve 17 on one side can be opened, and the air can be vented through the vent valve of the third control valve 19 on the other side, so that the dryer can be maintained without welding or releasing the refrigerant.

[0053] The dryer 18 is used to dry the refrigerant to prevent moisture from freezing and clogging the throttling and pressure-reducing device or corroding the pipeline.

[0054] For example, both the second control valve 17 and the third control valve 19 are shut-off valves. The dryer 18 is a replaceable core dryer for easy replacement and maintenance.

[0055] Optionally, the cooling circuit 1 also includes a night vision goggle 110, which is connected between the third control valve 19 and the dryer 18. The night vision goggle 110 is connected to the third control valve 19 and the dryer 18 respectively.

[0056] In the above implementation, the night vision goggles 110 are used to determine the refrigerant flow rate, bubbles, humidity, and oil contamination through their own observation window.

[0057] Optionally, the cooling circuit 1 also includes a liquid reservoir 111, which is connected between the second control valve 17 and the dryer 18, with its two ends connected to the second control valve 17 and the dryer 18, respectively.

[0058] When the cooling demand in the cab is low (such as at idle speed), the receiver 111 stores excess liquid refrigerant to prevent liquid slugging into the compressor 11. When the cooling demand is high (such as during high-temperature exposure), the stored refrigerant is released to ensure a continuous supply of liquid.

[0059] Figure 2 This is a schematic diagram of the evaporator structure. Figure 3 for Figure 2 The exploded view, combined with Figure 2 and Figure 3 Optionally, the evaporator 14 includes an evaporator shell 141, an evaporator core 142, an electric heating element 143, a fresh air module 144, and an evaporator fan 145. The evaporator core 142, the electric heating element 143, and the evaporator fan 145 are all located in the evaporator shell 141.

[0060] The fresh air module 144 is located outside the evaporator housing 141 and is connected to the evaporator housing 141. The fresh air module 144 has a fresh air duct 1440 inside, which is connected to both the inside and outside of the evaporator housing 141.

[0061] In the above implementation, the evaporator housing 141 provides a mounting base for the evaporator core 142, electric heating element 143, fresh air module 144, and evaporator fan 145. The evaporator core 142 facilitates heat exchange with the liquefied refrigerant. The liquefied refrigerant evaporates and absorbs heat within the evaporator core 142, cooling the air flowing through it. Specifically, hot air or fresh air from the cab is blown towards the evaporator core 142 by the evaporator fan 145. The low-temperature, low-pressure refrigerant evaporates within the evaporator core 142, carrying away heat from the air. The cooled, dry air is then introduced into the cab for cooling. Simultaneously, moisture in the air condenses on the surface of the evaporator core 142 and is discharged outside the vehicle through a drain pipe.

[0062] The electric heating element 143 is used for auxiliary heating, supplementing heat in low-temperature environments to quickly melt frost on the surface of the evaporator core 142 and maintain air conditioning efficiency. Furthermore, the electric heating element 143 can also supplement heat when the cab needs rapid warming, serving as a crucial compensation in low-temperature conditions, especially indispensable for electric trucks. The fresh air duct 1440 is used to filter fresh air.

[0063] Optionally, the fresh air module 144 includes a blower 1441 and an air filter 1442. The air filter 1442 is located at the inlet of the blower 1441 and connected to the blower 1441. The outlet of the blower 1441 communicates with the interior of the evaporator housing 141. The internal flow channel of the blower 1441 and the flow channel of the air filter 1442 together form the fresh air channel 1440.

[0064] In the above implementation, the fresh air module 144 is configured such that the blower 1441 and the air filter 1442 are connected in series through a sealed air duct and integrated into the front end of the mixing chamber of the evaporator shell 141, forming a complete airflow path of "filtration-pressurization-mixing-temperature regulation". The blower 1441 is the core of the airflow power. External air passes through the air filter 1442 and is pressurized by the blower 1441 before being sent into the evaporator shell 141. The blower 1441 continuously delivers air, making the air pressure in the cab slightly higher than that outside, allowing exhaust gas inside the cab to be automatically discharged, ensuring unidirectional airflow and preventing dust and toxic substances.

[0065] Figure 4 This is a schematic diagram of the condenser. Figure 5 for Figure 4 The exploded view, combined with Figure 4 and Figure 5Optionally, the condenser 12 includes a condenser housing 121, a condenser core 122, and a condenser fan 123. The condenser core 122 is embedded in one side wall of the condenser housing 121 and connected to the condenser housing 121. The condenser fan 123 is located in the condenser housing 121 and connected to the condenser housing 121.

[0066] The first bypass control valve 21, the second bypass control valve 22, the high-pressure switch 10, the compressor 11, the low-pressure switch 15, the first control valve 16, the second control valve 17, the dryer 18, and the third control valve 19 are all located in the condenser housing 121 and are connected to the condenser housing 121 respectively.

[0067] In the above implementation, the condenser housing 121 provides a mounting base for the above components. The condenser core 122 is used to condense the refrigerant. The condenser fan 123 is used for heat dissipation. This configuration allows for convenient system layout and is not limited by electrical specifications. Alternatively, the above equipment can be directly mounted on a rigid vehicle frame via the condenser housing 121.

[0068] Optionally, the refrigerant in compressor 11 is R410a refrigerant.

[0069] R410A (hydrofluorocarbon (HFC) mixture) is a mixed refrigerant widely used in air conditioning and heat pump systems. It consists of 50% R32 and 50% R125 and is a near-azeotropic mixture (temperature glide of only 0.1°C). R410A, as the refrigerant selected in the embodiments of this disclosure, can improve refrigeration efficiency.

[0070] The air conditioning system provided in this embodiment is powered by 380V AC power supplied by the vehicle, while the low-voltage control and sensor power supplies are provided by the inverter integrated into the panel. The air conditioning system is a top-mounted split-type structure, with the condenser 12 and evaporator 14 connected by pipes.

[0071] The working process of the air conditioning system provided in this embodiment is briefly described below:

[0072] When cooling is required, compressor 11 is started. The refrigerant is compressed by compressor 11, becoming a high-temperature, high-pressure gaseous state that enters condenser 12. The vaporized refrigerant exchanges heat with ambient air and undergoes a phase change in condenser 12, becoming a high-pressure liquid. This high-pressure liquid refrigerant then flows through throttling and pressure-reducing device 13 before entering evaporator 14. In evaporator 14, it exchanges heat, absorbing a large amount of heat to cool the cab, and simultaneously becomes a low-temperature, low-pressure gaseous state. This low-temperature, low-pressure gaseous refrigerant returns to compressor 11, forming a cycle. Simultaneously, the first bypass control valve 21 is opened, allowing a portion of the refrigerant compressed by compressor 11 to enter evaporator 14, achieving hot gas bypass function, regulating the system's cooling capacity, preventing frequent start-stop of compressor 11 under low load, and improving system reliability.

[0073] The above are merely optional embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. An air conditioning system for engineering machinery, characterized in that, The air conditioning system includes a cooling circuit (1) and a bypass branch (2). The cooling circuit (1) includes a compressor (11), a condenser (12), a throttling and pressure reducing device (13), and an evaporator (14) that are connected in sequence to form a circuit. The bypass branch (2) includes a first bypass control valve (21) and a second bypass control valve (22). One end of the first bypass control valve (21) is connected between the exhaust port of the compressor (11) and the condenser (12). The other end of the first bypass control valve (21) is connected to one end of the second bypass control valve (22). The other end of the second bypass control valve (22) is connected to the inlet of the evaporator (14). The first bypass control valve (21) is a normally closed solenoid valve, and the second bypass control valve (22) is a hot gas bypass valve.

2. The air conditioning system according to claim 1, characterized in that, The second bypass control valve (22) is a mechanical pressure valve.

3. The air conditioning system according to claim 2, characterized in that, The cooling circuit (1) also includes a high-voltage switch (10) and / or a low-voltage switch (15). The high-pressure switch (10) is connected to the exhaust port of the compressor (11); The low-pressure switch (15) is connected in the passage between the evaporator (14) and the compressor (11).

4. The air conditioning system according to claim 3, characterized in that, The air conditioning system also includes a controller, which is electrically connected to the high-pressure switch (10), the first bypass control valve (21) and the low-pressure switch (15), respectively.

5. The air conditioning system according to any one of claims 1-4, characterized in that, The evaporator (14) includes an evaporation shell (141), an evaporation core (142), an electric heating element (143), a fresh air module (144), and an evaporation fan (145). The evaporation core (142), the electric heating element (143), and the evaporation fan (145) are all located in the evaporation shell (141). The fresh air module (144) is located outside the evaporator shell (141) and connected to the evaporator shell (141). The fresh air module (144) has a fresh air channel (1440) for filtration inside. The fresh air channel (1440) is connected to the inside and outside of the evaporator shell (141) respectively.

6. The air conditioning system according to claim 5, characterized in that, The fresh air module (144) includes a blower (1441) and an air filter (1442). The air filter (1442) is located at the air inlet of the blower (1441) and is connected to the blower (1441). The outlet of the blower (1441) is connected to the interior of the evaporator shell (141).

7. The air conditioning system according to claim 4, characterized in that, The cooling circuit (1) further includes a first control valve (16), the two ends of which are connected to the condenser (12) and the throttling and pressure reducing device (13), respectively. When the compressor (11) is started, the first control valve (16) is in the open state, and when the compressor (11) is stopped, the first control valve (16) is in the closed state.

8. The air conditioning system according to claim 7, characterized in that, The cooling circuit (1) also includes a second control valve (17), a dryer (18) and a third control valve (19), which are connected in series between the first control valve (16) and the condenser (12).

9. The air conditioning system according to claim 8, characterized in that, The condenser (12) includes a condenser shell (121), a condenser core (122), and a condenser fan (123). The condenser core (122) is embedded in one side wall of the condenser shell (121) and connected to the condenser shell (121). The condenser fan (123) is located in the condenser housing (121) and connected to the condenser housing (121); The first bypass control valve (21), the second bypass control valve (22), the high-pressure switch (10), the compressor (11), the low-pressure switch (15), the first control valve (16), the second control valve (17), the dryer (18), and the third control valve (19) are all located in the condenser housing (121) and are respectively connected to the condenser housing (121).

10. The air conditioning system according to any one of claims 1-4 and 6-9, characterized in that, The refrigerant in the compressor (11) is R410a refrigerant.

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