Air conditioning system, work machine, and control method

Abstract

The present invention relates to the technical field of air conditioning equipment for new energy vehicles, and provides an air conditioning system for a working machine, an electric working machine, and a control method. The refrigeration system includes: a heating device, an internal heat exchanger, a three-way valve, a plate heat exchanger, and a flow control valve; the heating device, the internal heat exchanger, and the three-way valve form a first coolant circuit, the plate heat exchanger and the flow control valve form a second coolant circuit, and the plate heat exchanger, the internal heat exchanger, and the three-way valve form a third coolant circuit; the plate heat exchanger is also thermally coupled to the refrigerant circuit, and the three-way valve can switch the connection ends and cooperate with the flow control valve to enable the coolant to enter the first coolant circuit or the third coolant circuit to cool or heat the cab; the flow control valve can adjust the opening degree to control the flow rate of the coolant entering the second coolant circuit to cool or heat the power battery; multiple cooling and heating modes can be combined to expand the air conditioning temperature adjustment range.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning equipment for new energy vehicles, and particularly relates to an air conditioning system for working machinery, an electric working machinery, and a control method. Background Art

[0002] Currently, in the refrigeration and heating management system of new energy vehicles, the air conditioning and the cooling of the power battery adopt a cooling system equipped with 2 evaporators to provide a cold source. An HVAC air conditioning box is arranged on the air conditioning side, which includes an evaporator for refrigeration and a heater core for heating. A plate heat exchanger is arranged on the power battery cooling system side, and low-temperature refrigerant is introduced to cool the coolant on the battery side to achieve battery temperature reduction.

[0003] In the existing new energy vehicles, the coolant circuit has a refrigeration function for the power battery, but does not have a heating function. The air conditioning temperature adjustment range is narrow, and its control only involves the control of the hot water valve on the coolant circuit. The refrigeration capacity adjustment range is small and does not meet the refined adjustment requirements. Summary of the Invention

[0004] The present invention provides an air conditioning system for working machinery, an electric working machinery, and a control method to solve the defect that the air conditioning temperature adjustment range of the air conditioning system in existing new energy vehicles is narrow.

[0005] The present invention provides an air conditioning system for working machinery, including: a heating device, an internal heat exchanger, a three-way valve, a plate heat exchanger, and a flow control valve; wherein,

[0006] The heating device, the internal heat exchanger, and the three-way valve are sequentially connected to form a first coolant circuit, the plate heat exchanger and the flow control valve are sequentially connected to form a second coolant circuit for cooling or heating the power battery, and the plate heat exchanger, the internal heat exchanger, and the three-way valve are sequentially connected to form a third coolant circuit;

[0007] Wherein, the plate heat exchanger is also thermally coupled with the refrigerant circuit, the three-way valve can switch the connection end and cooperate with the flow control valve to enable the coolant to enter the first coolant circuit or the third coolant circuit, and the flow control valve can adjust the opening degree to control the flow rate of the coolant entering the second coolant circuit.

[0008] According to an air conditioning system for working machinery provided by the present invention, the refrigerant circuit includes a compressor, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, an external heat exchanger, an expansion valve, and a gas-liquid separator; wherein,

[0009] The compressor, the first solenoid valve, the plate heat exchanger, the expansion valve, the external heat exchanger, the second solenoid valve, and the gas-liquid separator are sequentially connected to form a heating circuit;

[0010] The compressor, the third solenoid valve, the external heat exchanger, the expansion valve, the plate heat exchanger, the fourth solenoid valve, and the gas-liquid separator are connected in sequence to form a refrigeration circuit.

[0011] An operating machinery air conditioning system according to the present invention further includes a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a pressure temperature sensor. The first temperature sensor is disposed on the external heat exchanger, the second temperature sensor is disposed between the external heat exchanger and the expansion valve, the third temperature sensor is disposed between the first solenoid valve and the plate heat exchanger, the fourth temperature sensor is disposed between the gas-liquid separator and the compressor, and the pressure temperature sensor is disposed at the exhaust port of the compressor.

[0012] An operating machinery air conditioning system according to the present invention further includes a first expansion tank and a second expansion tank. The first expansion tank is connected between the heating device and the three-way valve, and the second expansion tank is connected between the three-way valve and the plate heat exchanger.

[0013] In an operating machinery air conditioning system according to the present invention, the three-way valve includes a first connection end, a second connection end, and a third connection end. The first connection end is connected to the second coolant circuit, and the second connection end and the third connection end are respectively connected to the first coolant circuit.

[0014] An operating machinery air conditioning system according to the present invention further includes a fifth temperature sensor, a sixth temperature sensor, and a seventh temperature sensor. The fifth temperature sensor is disposed at the inlet of the plate heat exchanger on the side of the second coolant circuit, the sixth temperature sensor is disposed at the outlet of the plate heat exchanger on the side of the second coolant circuit, and the seventh temperature sensor is disposed at the water outlet of the power battery.

[0015] An operating machinery air conditioning system according to the present invention further includes a first check valve and a second check valve. The first check valve is disposed in the first coolant circuit, and the second check valve is disposed in the second coolant circuit.

[0016] The present invention also provides an electric operating machinery, including: the operating machinery air conditioning system of the embodiment of the present invention.

[0017] The present invention also provides a control method for an operating machinery air conditioning system, including:

[0018] In response to the switching of the connection end of the three-way valve, the coolant enters the first coolant circuit and circulates among the heating device, the internal heat exchanger, and the three-way valve, or enters the third coolant circuit and circulates among the plate heat exchanger, the internal heat exchanger, and the three-way valve;

[0019] In response to the adjustment of the opening degree of the flow control valve, the coolant enters the second coolant circuit and circulates between the plate heat exchanger and the flow control valve.

[0020] A control method for an air-conditioning system of a working machine provided by the present invention further includes:

[0021] The refrigerant circuit generates cooling capacity. The flow control valve is closed, and the three-way valve is adjusted to make the coolant enter the third coolant circuit. The temperature of the coolant is reduced through heat exchange by the plate heat exchanger, and the internal heat exchanger is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide cooling capacity in the cab cooling mode.

[0022] A control method for an air-conditioning system of a working machine provided by the present invention further includes:

[0023] The refrigerant circuit generates cooling capacity. The three-way valve is adjusted to make the coolant enter the third coolant circuit. The temperature of the coolant is reduced through heat exchange by the plate heat exchanger, and the internal heat exchanger is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank; meanwhile, by adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to cool the power battery, and the coolant returns to the plate heat exchanger through the second expansion tank to provide cooling capacity in the cab cooling and battery cooling modes.

[0024] A control method for an air-conditioning system of a working machine provided by the present invention further includes:

[0025] The refrigerant circuit generates heat. The flow control valve is closed, and the three-way valve is adjusted to make the coolant enter the third coolant circuit. The temperature of the coolant is increased through heat exchange by the plate heat exchanger, and the internal heat exchanger is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat in the cab heating mode.

[0026] A control method for an air-conditioning system of a working machine provided by the present invention further includes:

[0027] The refrigerant circuit generates heat during heating. The temperature of the coolant is reduced through heat exchange in the plate heat exchanger. By adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to cool the power battery. The coolant returns to the plate heat exchanger through the second expansion tank. At the same time, by adjusting the three-way valve, the coolant enters the first coolant circuit, the coolant in the first coolant circuit is heated by the heating device, and heat is provided to the cab interior using the internal heat exchanger. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat for the cab and cold for the power battery respectively in the cab heating and battery cooling modes.

[0028] A control method for an air conditioning system of a work machine according to the present invention further includes:

[0029] The refrigerant circuit generates heat during heating. The temperature of the coolant is increased through heat exchange in the plate heat exchanger. By adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to heat the power battery. The coolant returns to the plate heat exchanger through the second expansion tank. At the same time, by adjusting the three-way valve, the coolant enters the first coolant circuit, and heat is provided to the cab interior using the internal heat exchanger. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat in the cab heating and battery heating modes.

[0030] A control method for an air conditioning system of a work machine according to the present invention further includes:

[0031] Open the third solenoid valve and the fourth solenoid valve, close the first solenoid valve and the second solenoid valve. The refrigerant discharged from the compressor enters the external heat exchanger through the third solenoid valve, is throttled by the expansion valve and then enters the plate heat exchanger, exchanges heat with the coolant, and then enters the compressor cycle through the fourth solenoid valve and the gas-liquid separator to refrigerate in the refrigeration circuit.

[0032] A control method for an air conditioning system of a work machine according to the present invention further includes:

[0033] Open the first solenoid valve and the second solenoid valve, close the third solenoid valve and the fourth solenoid valve. The refrigerant discharged from the compressor enters the plate heat exchanger through the first solenoid valve, exchanges heat with the coolant, the refrigerant condenses and then is throttled by the expansion valve and enters the external heat exchanger, and then enters the compressor cycle through the second solenoid valve and the gas-liquid separator to heat in the heating circuit.

[0034] An air conditioning system for a work machine provided by the present invention controls the coolant to enter the corresponding branch by setting three different coolant circuits and using a three-way valve and a flow control valve, thereby cooling or heating the cab and cooling or heating the power battery to improve the battery life; by the coolant entering different branches, multiple cooling and heating modes can be combined to expand the air conditioning temperature adjustment range; in addition, the present invention adopts a water-cooled refrigeration system form, reduces the number of heat exchangers in the HVAC air conditioning box, and reduces costs; reduces refrigerant and coolant pipelines, reduces pipeline pressure loss, and improves system performance.

[0035] Furthermore, the present invention also provides an electric work machine, which has the same advantages as above because it includes the air conditioning system for a work machine in the above embodiment.

[0036] Even further, the present invention also provides a control method for an air conditioning system for a work machine. By adjusting the connection ends of the three-way valve, the coolant enters different cooling branches, thereby realizing the cooling or heating of the cab, and by adjusting the flow control valve, the cooling and heating of the power battery are realized; multiple temperature adjustment methods are provided to expand the air conditioning temperature adjustment range; in addition, the present invention adopts a water-cooled refrigeration system form, reduces the number of heat exchangers in the HVAC air conditioning box, and reduces costs; reduces refrigerant and coolant pipelines, reduces pipeline pressure loss, and improves system performance. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic diagram of the principle of the air conditioning system for a work machine provided by the present invention;

[0039] Figure 2 It is a schematic diagram of the process for adjusting the opening degree of the regulating valve, the rotational speed of the water pump, and the rotational speed of the compressor in the control method of the air conditioning system for a work machine provided by the present invention;

[0040] Reference Signs:

[0041] 1: Heating device; 2: Internal heat exchanger; 3, Three-way valve; 31: First connection end; 32: Second connection end; 33: Third connection end; 4: First expansion tank; 5: Plate heat exchanger; 6: Flow control valve; 7: Second expansion tank; 9: Power battery; 10: Compressor; 11: First solenoid valve; 12: Expansion valve; 13: External heat exchanger; 14: Second solenoid valve; 15: Gas-liquid separator; 16: Third solenoid valve; 17: Fourth solenoid valve; 18: First temperature sensor; 19: Second temperature sensor; 20: Third temperature sensor; 21: Fourth temperature sensor; 22: Pressure and temperature sensor; 23: Fifth temperature sensor; 24: Sixth temperature sensor; 25: Seventh temperature sensor; 26: First check valve; 27: Second check valve; 28: First water pump; 29: Second water pump. Detailed implementation manners

[0042] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0043] The following Figure 1 describes an air conditioning system for a working machine of the present invention. The air conditioning system for the working machine includes a heating device 1, an internal heat exchanger 2, a three-way valve 3, a plate heat exchanger 5 and a flow control valve 6; wherein,

[0044] The heating device 1, the internal heat exchanger 2 and the three-way valve 3 are sequentially connected to form a first coolant circuit, the plate heat exchanger 5 and the flow control valve 6 are sequentially connected to form a second coolant circuit for cooling or heating the power battery 9, and the plate heat exchanger 5, the internal heat exchanger 2 and the three-way valve 3 are sequentially connected to form a third coolant circuit;

[0045] Wherein, the plate heat exchanger 5 is also thermally coupled to the refrigerant circuit, the three-way valve 3 can switch the connection end to enable the coolant to enter the first coolant circuit or the third coolant circuit, and the flow control valve 6 can adjust the opening degree to control the flow rate of the coolant entering the second coolant circuit.

[0046] Specifically, in the refrigerant circuit, by exhausting and sucking air by the compressor 10 and adjusting the corresponding solenoid valves, the refrigerant provides cold or heat, and exchanges heat with the coolant in the coolant circuit through the plate heat exchanger 5.

[0047] The first coolant circuit consists of a heating device 1, an internal heat exchanger 2, and a three-way valve 3 connected in sequence by pipelines. The coolant in the first coolant circuit exchanges heat with the refrigerant in the refrigerant circuit through a plate heat exchanger 5. This branch is mainly used for the heating mode in the cab. The coolant in this branch is heated by the heating device 1, and then heat is provided to the cab through the internal heat exchanger 2. Of course, if the refrigerant provides heat and can meet the temperature requirements in the cab, the heating device 1 can be turned off and only allow the coolant to pass through. Preferably, the heating device 1 in the first coolant circuit uses a water PTC heater. Of course, according to the actual situation, other waterproof heaters can also be used for replacement.

[0048] The second coolant circuit consists of a plate heat exchanger 5 and a flow control valve 6 connected in sequence by pipelines. The second coolant circuit is used to provide heat or cold to the power battery 9. The coolant in the second coolant circuit exchanges heat with the refrigerant in the refrigerant circuit through the plate heat exchanger 5. This branch is mainly used for the cooling and heating modes of the power battery 9. If the refrigerant provides cold, the coolant exchanges heat through the plate heat exchanger 5 to cool the power battery 9. If the refrigerant provides heat, the coolant exchanges heat through the plate heat exchanger 5 to heat the power battery 9. Specifically, in the second coolant circuit, the flow control valve 6 can be used to control the flow rate of the coolant entering the power battery 9, thereby controlling the cooling and heating effects of the power battery 9. If the flow control valve 6 is closed, the power battery 9 is not cooled or heated.

[0049] The third coolant circuit includes a plate heat exchanger 5, an internal heat exchanger 2, and a three-way valve 3 connected in sequence. The coolant in the third coolant circuit exchanges heat with the refrigerant in the refrigerant circuit through the plate heat exchanger 5. This branch is mainly used for the cooling or heating mode in the cab. If the refrigerant provides cold, the coolant is cooled through the plate heat exchanger 5, and the cold provided by the coolant is transferred to the cab through the internal heat exchanger 2. If the refrigerant provides heat, the coolant is heated through the plate heat exchanger 5, and the heat provided by the coolant is transferred to the cab through the internal heat exchanger 2.

[0050] Among them, the coolant is switched in the first cooling branch, the second coolant circuit, and the third cooling branch through the three-way valve 3 and the flow control valve 6, so that it is heat-exchanged and connected to the refrigerant circuit through the plate heat exchanger 5. Specifically, the first connection end 31, the second connection end 32, and the third connection end 33 of the three-way valve 3 and the opening degree of the flow control valve 6 are used to switch the coolant to enter different branches, such as Figure 1As shown, when the first connection end 31 and the second connection end 32 of the three-way valve 3 are connected, the coolant moves along the third cooling branch; when the second connection end 32 and the third connection end 33 of the three-way valve 3 are connected, the coolant moves along the first coolant circuit; the flow rate of the coolant entering the second coolant circuit is controlled by controlling the opening degree of the flow control valve 6. The actions of the flow control valve 6 and the three-way valve 3 do not conflict, and the cab and the power battery can be cooled or heated simultaneously.

[0051] An operating machinery air conditioning system provided by the present invention controls the coolant to enter the corresponding branch by setting three different coolant circuits and using the three-way valve 3 and the flow control valve 6, so as to cool or heat the cab and cool or heat the power battery 9, improving the battery life; by the coolant entering different branches, multiple cooling and heating modes can be combined to expand the air conditioning temperature adjustment range. In addition, the present invention adopts a water-cooled refrigeration system form, reducing the number of heat exchangers in the HVAC air conditioning box and reducing costs; reducing refrigerant and coolant pipelines, reducing pipeline pressure loss, and improving system performance.

[0052] In one embodiment of the present invention, the refrigerant circuit includes a compressor 10, a first solenoid valve 11, a second solenoid valve 14, a third solenoid valve 16, a fourth solenoid valve 17, an external heat exchanger 13, an expansion valve 12 and a gas-liquid separator 15; wherein, the compressor 10, the first solenoid valve 11, the plate heat exchanger 5, the expansion valve 12, the external heat exchanger 13, the second solenoid valve 14 and the gas-liquid separator 15 are connected in sequence to form a heating circuit; the compressor 10, the third solenoid valve 16, the external heat exchanger 13, the expansion valve 12, the plate heat exchanger 5, the fourth solenoid valve 17 and the gas-liquid separator 15 are connected in sequence to form a refrigeration circuit. Specifically, when the refrigeration circuit works, the third solenoid valve 16 and the fourth solenoid valve 17 are opened, the first solenoid valve 11 and the second solenoid valve 14 are closed, the refrigerant discharged from the compressor 10 enters the external heat exchanger 13 through the third solenoid valve 16, is throttled by the expansion valve 12 and then enters the plate heat exchanger 5 to exchange heat with the coolant, and then enters the compressor 10 through the fourth solenoid valve 17 and the gas-liquid separator 15 for circulation. In this mode, the refrigerant exchanges heat with the coolant through the plate heat exchanger 5 to reduce the coolant temperature; when the heating circuit works, the first solenoid valve 11 and the second solenoid valve 14 are opened, the third solenoid valve 16 and the fourth solenoid valve 17 are closed, the refrigerant discharged from the compressor 10 enters the plate heat exchanger 5 through the first solenoid valve 11 to exchange heat with the coolant, the refrigerant condenses and then is throttled by the expansion valve 12 and enters the external heat exchanger 13, and then enters the compressor 10 through the second solenoid valve 14 and the gas-liquid separator 15 for circulation. In this mode, the refrigerant exchanges heat with the coolant through the plate heat exchanger 5 to increase the coolant temperature.

[0053] In one embodiment of the present invention, the construction machinery air conditioning system further includes a first temperature sensor 18, a second temperature sensor 19, a third temperature sensor 20, a fourth temperature sensor 21, and a pressure temperature sensor 22. The first temperature sensor 18 is disposed on the external heat exchanger 13, the second temperature sensor 19 is disposed between the external heat exchanger 13 and the expansion valve 12, the third temperature sensor 20 is disposed between the first solenoid valve 11 and the plate heat exchanger 5, the fourth temperature sensor 21 is disposed between the gas-liquid separator 15 and the compressor 10, and the pressure temperature sensor 22 is disposed at the exhaust port of the compressor 10. In this embodiment, temperature sensors are arranged at different positions to monitor the temperature changes of the refrigerant when passing through different positions, and the pressure temperature sensor 22 is arranged to monitor the pressure and temperature changes of the coolant, so as to adjust the exhaust volume and suction volume of the compressor 10.

[0054] In one embodiment of the present invention, the construction machinery air conditioning system further includes a first expansion tank 4 and a second expansion tank 7. The first expansion tank 4 is connected between the heating device 1 and the three-way valve 3, and the second expansion tank 7 is connected between the three-way valve 3 and the plate heat exchanger 5. Specifically, the first expansion tank 4 is connected in the first coolant circuit, and the second expansion tank 7 is connected in the second coolant circuit and the third coolant circuit.

[0055] In one embodiment of the present invention, the construction machinery air conditioning system further includes a first water pump 28 and a second water pump 29. The first water pump 28 is disposed between the first expansion tank 4 and the heating device 1, and the second water pump 29 is disposed between the second expansion tank 7 and the plate heat exchanger 5. In this embodiment, the first water pump 28 provides a driving force for the directional movement of the coolant in the first coolant circuit to form a coolant circulation circuit, and the second water pump 29 provides a driving force for the directional movement of the coolant in the second coolant circuit and the third coolant circuit to form a coolant circulation circuit.

[0056] In one embodiment of the present invention, the three-way valve 3 includes a first connection end 31, a second connection end 32, and a third connection end 33. The first connection end 31 is connected to the second coolant circuit, and the second connection end 32 and the third connection end 33 are respectively connected to the first coolant circuit. Specifically, the first connection end 31 is connected between the second expansion tank 7 and the power battery 9, and the second connection end 32 and the third connection end 33 are respectively connected to the first coolant circuit. By switching the connection mode of the three-way valve 3, the coolant can enter the first coolant circuit or the third coolant circuit accordingly. When the first connection end 31 and the second connection end 32 of the three-way valve 3 are connected, the coolant moves along the third cooling branch; when the second connection end 32 and the third connection end 33 of the three-way valve 3 are connected, the coolant moves along the first coolant circuit.

[0057] In one embodiment of the present invention, the construction machinery air conditioning system further includes a fifth temperature sensor 23, a sixth temperature sensor 24, and a seventh temperature sensor 25. The fifth temperature sensor 23 is disposed at the inlet of the plate heat exchanger 5 on the side of the second coolant circuit, the sixth temperature sensor 24 is disposed at the outlet of the plate heat exchanger 5 on the side of the second coolant circuit, and the seventh temperature sensor 25 is disposed at the water outlet of the power battery 9. In this embodiment, by arranging temperature sensors at the inlet and outlet of the plate heat exchanger 5 and the water outlet of the power battery 9, the temperature changes of the coolant at different positions can be monitored.

[0058] In one embodiment of the present invention, the construction machinery air conditioning system further includes a first check valve 26 and a second check valve 27. The first check valve 26 is disposed in the first coolant circuit, and the second check valve 27 is disposed in the second coolant circuit. In this embodiment, the first check valve 26 is used to make the coolant move directionally in the first coolant circuit, and the second check valve 27 is used to make the coolant move directionally in the second coolant circuit.

[0059] The present invention also provides an electric construction machinery. The electric construction machinery can be an electric vehicle, an electric excavator, an electric crane, an electric fire truck, etc., and includes the construction machinery air conditioning system of the above embodiment. Since the electric construction machinery includes the construction machinery air conditioning system of the above embodiment, it has the same advantages as above.

[0060] The present invention also provides a control method for a construction machinery air conditioning system. The control method includes: in response to the switching of the connection end of the three-way valve, making the coolant enter the first coolant circuit and circulate between the heating device 1, the internal heat exchanger, and the three-way valve, or enter the third coolant circuit and circulate between the plate heat exchanger, the internal heat exchanger, and the three-way valve; in response to the adjustment of the opening degree of the flow control valve, making the coolant enter the second coolant circuit and circulate between the plate heat exchanger and the flow control valve.

[0061] The control method for a construction machinery air conditioning system provided by the present invention realizes the refrigeration or heating of the cab by adjusting the connection end of the three-way valve to make the coolant enter different cooling branches, and realizes the cooling and heating of the power battery by adjusting the flow control valve; provides a variety of temperature adjustment methods, and improves the air conditioning temperature adjustment range.

[0062] Further, the adjustment by the control method of the construction machinery air conditioning system includes the following five modes: cab refrigeration mode, cab refrigeration and battery cooling mode, cab heating mode, cab heating and battery cooling mode, and cab heating and battery heating mode.

[0063] In the cab refrigeration mode, the refrigerant circuit refrigerates to generate cooling capacity. The flow control valve 6 is closed, and the coolant is made to enter the third coolant circuit by adjusting the three-way valve 3 (connecting the first connection end 31 and the second connection end 32). The temperature of the coolant is reduced through heat exchange in the plate heat exchanger 5, and the internal heat exchanger 2 is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7 to provide cooling capacity in the cab refrigeration mode.

[0064] In the cab refrigeration and battery cooling modes, the refrigerant circuit refrigerates to generate cooling capacity. The coolant is made to enter the third coolant circuit by adjusting the three-way valve 3 (connecting the first connection end 31 and the second connection end 32). The temperature of the coolant is reduced through heat exchange in the plate heat exchanger 5, and the internal heat exchanger 2 is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7. At the same time, by adjusting the opening degree of the flow control valve 6, the flow rate of the coolant flowing into the power battery 9 is adjusted to cool the power battery 9. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7 to provide cooling capacity in the cab refrigeration and battery cooling modes.

[0065] In the cab heating mode, the refrigerant circuit heats to generate heat. The flow control valve 6 is closed, and the coolant is made to enter the third coolant circuit by adjusting the three-way valve 3 (connecting the first connection end 31 and the second connection end 32). The temperature of the coolant is increased through heat exchange in the plate heat exchanger 5, and the internal heat exchanger 2 is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7 to provide heat in the cab heating mode.

[0066] In the cab heating and battery cooling modes, the refrigerant circuit refrigerates to generate cooling capacity. The temperature of the coolant is reduced through heat exchange in the plate heat exchanger 5. By adjusting the opening degree of the flow control valve 6, the flow rate of the coolant flowing into the power battery 9 is adjusted to cool the power battery 9. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7. At the same time, the coolant is made to enter the first coolant circuit by adjusting the three-way valve 3 (connecting the second connection end 32 and the third connection end 33). The heating device 1 (i.e., the water PTC heater) is used to heat the coolant in the first coolant circuit, and the internal heat exchanger 2 is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7 to provide heat for the cab and cooling capacity for the power battery respectively in the cab heating and battery cooling modes.

[0067] In the cab heating and battery heating modes, the refrigerant circuit generates heat, which is exchanged through the plate heat exchanger 5 to increase the temperature of the coolant. By adjusting the opening degree of the flow control valve 6, the flow rate of the coolant flowing into the power battery 9 is adjusted to heat the power battery 9. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7. At the same time, by adjusting the three-way valve 3 (connected to the second connection end 32 and the third connection end 33), the coolant enters the first coolant circuit, and heat is provided to the cab interior by using the internal heat exchanger 2. The coolant returns to the plate heat exchanger 5 through the second expansion tank 7. Since the coolant provides heat in this mode, the heating device 1 (i.e., the water PTC heater) can be turned on for heating or can be left off for only the coolant to pass through. It is determined whether to turn on the heating device 1 based on the temperature target in the cab and the temperature of the coolant, so as to provide heat for the cab and cold for the power battery respectively in the cab heating and battery cooling modes.

[0068] In one embodiment of the present invention, when the refrigerant circuit performs refrigeration, the third solenoid valve 16 and the fourth solenoid valve 17 are opened, and the first solenoid valve 11 and the second solenoid valve 14 are closed. The refrigerant discharged from the compressor 10 enters the external heat exchanger 13 through the third solenoid valve 16, is throttled by the expansion valve 12, then enters the plate heat exchanger 5, exchanges heat with the coolant, and then enters the compressor 10 through the fourth solenoid valve 17 and the gas-liquid separator 15 for circulation to perform refrigeration in the refrigeration circuit. When the refrigerant circuit performs heating, the first solenoid valve 11 and the second solenoid valve 14 are opened, and the third solenoid valve 16 and the fourth solenoid valve 17 are closed. The refrigerant discharged from the compressor 10 enters the plate heat exchanger 5 through the first solenoid valve 11, exchanges heat with the coolant, the refrigerant condenses and then is throttled by the expansion valve 12 and enters the external heat exchanger 13, and then enters the compressor 10 through the second solenoid valve 14 and the gas-liquid separator 15 for circulation to perform heating in the heating circuit.

[0069] In one embodiment of the present invention, as Figure 2 shown, the opening degree of the flow control valve, the rotational speed of the water pump, and the rotational speed of the compressor 10 are controlled by the following formula:

[0070] When ΔT ≤ ΔT 目标 , at this time, the cooling rate ΔT m is not judged, the opening degree deviation of the flow control valve is u, and the change amount is Δu, the opening degree u1 = u0 + Δu;

[0071] When ΔT ≤ ΔT 目标 , and within 30 minutes after the adjustment of the regulating valve, the battery temperature difference t = T b - T2 > t 目标 , that is, it is determined that the opening degree of the flow control valve cannot meet the requirement of battery temperature adjustment, and it is switched to adjusting the rotational speed of the water pump according to PID until t ≤ t 目标 ;

[0072] When ΔT > ΔT 目标 , and the water temperature change rate ΔT m ≥ΔT m(目标) , adjust the rotation speed of the compressor 10 according to the first PID method

[0073] When ΔT > ΔT 目标 , and the water temperature change rate ΔT m <ΔT m(目标) , adjust the rotation speed of the compressor 10 according to the second PID method Where k s =αk p ', where α is a constant greater than 1;

[0074] Where the air conditioner temperature set by the user is T1, the target water temperature of the battery is T2, the water outlet temperature of the battery is T b , the target water temperature of the air conditioner is T a , the target outlet water temperature of the plate heat exchanger 5 is T 设 , the actual outlet water temperature of the plate heat exchanger 5 is T 出水 , T 出水 -T 设 The set target value of the difference between them is ΔT 目标 , the set target value of ΔT m is ΔT m(目标) , and A is a constant;

[0075] ΔT = T 出水 -T 设 , and the cooling rate of the outlet water temperature of the plate heat exchanger 5 within n minutes According to the actual cooling curve, it can be obtained that T 设 =min(T a , T b ).

[0076] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0077] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for an air conditioning system of a work machine, characterized in that, Comprising: In response to the switching of the connection end of the three-way valve, the coolant enters the first coolant circuit and circulates among the heating device, the internal heat exchanger and the three-way valve, or enters the third coolant circuit and circulates among the plate heat exchanger, the internal heat exchanger and the three-way valve; In response to the adjustment of the opening degree of the flow control valve, the coolant enters the second coolant circuit and circulates between the plate heat exchanger and the flow control valve; The refrigerant circuit generates cooling capacity. The flow control valve is closed, and by adjusting the three-way valve, the coolant enters the third coolant circuit. The temperature of the coolant is reduced through heat exchange in the plate heat exchanger, and the internal heat exchanger is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide cooling capacity in the cab cooling mode; The refrigerant circuit generates cooling capacity. By adjusting the three-way valve, the coolant enters the third coolant circuit. The temperature of the coolant is reduced through heat exchange in the plate heat exchanger, and the internal heat exchanger is used to provide cooling capacity to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank; meanwhile, by adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to cool the power battery. The coolant returns to the plate heat exchanger through the second expansion tank to provide cooling capacity in the cab cooling and battery cooling modes; The refrigerant circuit generates heat. The flow control valve is closed, and by adjusting the three-way valve, the coolant enters the third coolant circuit. The temperature of the coolant is increased through heat exchange in the plate heat exchanger, and the internal heat exchanger is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat in the cab heating mode; The refrigerant circuit generates heat. The temperature of the coolant is reduced through heat exchange in the plate heat exchanger. By adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to cool the power battery. The coolant returns to the plate heat exchanger through the second expansion tank; meanwhile, by adjusting the three-way valve, the coolant enters the first coolant circuit, and the heating device is used to heat the coolant in the first coolant circuit, and the internal heat exchanger is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat for the cab and cooling capacity for the power battery respectively in the cab heating and battery cooling modes; The refrigerant circuit generates heat. The temperature of the coolant is increased through heat exchange in the plate heat exchanger. By adjusting the opening degree of the flow control valve, the flow rate of the coolant flowing into the power battery is adjusted to heat the power battery. The coolant returns to the plate heat exchanger through the second expansion tank; meanwhile, by adjusting the three-way valve, the coolant enters the first coolant circuit, and the internal heat exchanger is used to provide heat to the cab interior. The coolant returns to the plate heat exchanger through the second expansion tank to provide heat in the cab heating and battery heating modes; 2. An operating machinery air conditioning system using the control method of the operating machinery air conditioning system according to claim 1, characterized in that, Comprising: A heating device, an internal heat exchanger, a three-way valve, a plate heat exchanger and a flow control valve; wherein, The heating device, the internal heat exchanger, and the three-way valve are connected in sequence to form a first coolant circuit. The plate heat exchanger and the flow control valve are connected in sequence to form a second coolant circuit for cooling or heating the power battery. The plate heat exchanger, the internal heat exchanger, and the three-way valve are connected in sequence to form a third coolant circuit; Wherein, the plate heat exchanger is also thermally coupled to the refrigerant circuit. The three-way valve can switch the connection ends and cooperate with the flow control valve to enable the coolant to enter the first coolant circuit or the third coolant circuit. The flow control valve can adjust the opening degree to control the flow rate of the coolant entering the second coolant circuit.

3. The work machine air conditioning system according to claim 2, characterized in that, The refrigerant circuit includes a compressor, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, an external heat exchanger, an expansion valve, and a gas-liquid separator; wherein, The compressor, the first solenoid valve, the plate heat exchanger, the expansion valve, the external heat exchanger, the second solenoid valve, and the gas-liquid separator are connected in sequence to form a heating circuit; The compressor, the third solenoid valve, the external heat exchanger, the expansion valve, the plate heat exchanger, the fourth solenoid valve, and the gas-liquid separator are connected in sequence to form a refrigeration circuit.

4. The construction machine air-conditioning system according to claim 3, wherein, It further includes a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, and a pressure temperature sensor. The first temperature sensor is disposed on the external heat exchanger. The second temperature sensor is disposed between the external heat exchanger and the expansion valve. The third temperature sensor is disposed between the first solenoid valve and the plate heat exchanger. The fourth temperature sensor is disposed between the gas-liquid separator and the compressor. The pressure temperature sensor is disposed at the exhaust port of the compressor.

5. The work machine air conditioning system according to claim 2, characterized in that, It further includes a first expansion tank and a second expansion tank. The first expansion tank is connected between the heating device and the three-way valve. The second expansion tank is connected between the three-way valve and the plate heat exchanger.

6. The work machine air conditioning system according to claim 2, characterized in that, The three-way valve includes a first connection end, a second connection end, and a third connection end. The first connection end is connected to the second coolant circuit. The second connection end and the third connection end are respectively connected to the first coolant circuit.

7. The construction machinery air conditioning system according to claim 2, wherein It further includes a fifth temperature sensor, a sixth temperature sensor, and a seventh temperature sensor. The fifth temperature sensor is disposed at the inlet of the plate heat exchanger on the side of the second coolant circuit. The sixth temperature sensor is disposed at the outlet of the plate heat exchanger on the side of the second coolant circuit. The seventh temperature sensor is disposed at the water outlet of the power battery.

8. The construction machine air-conditioning system according to any one of claims 2 to 7, characterized in that It further includes a first check valve and a second check valve. The first check valve is disposed in the first coolant circuit. The second check valve is disposed in the second coolant circuit.

9. An electric working machine, characterized in that, Comprising: The work machine air conditioning system according to any one of claims 2 to 8.

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