Storage battery driven low-power-consumption air conditioner for vehicle

Abstract

The present invention relates to a battery-driven low-power air conditioner for a vehicle, and more particularly, to a battery-driven low-power air conditioner for a vehicle, which can minimize power consumption and improve refrigeration performance. A battery-driven low-power air conditioner for a vehicle according to the present invention comprises: a compressor for compressing and discharging a refrigerant; an electric actuator for supplying rotational force to the compressor; a battery for supplying power to the electric device; the speed reducer enables the electric device and the compressor to be connected according to the speed reduction ratio of 3: 1; a condenser for condensing the high-pressure refrigerant discharged from the compressor; a capillary through which the refrigerant liquefied by the condenser passes under reduced pressure; an evaporator for vaporizing the refrigerant passing through the capillary tube by heat exchange with steam heat; and a cooling unit that cools the electric device by means of a refrigerant received from the evaporator and then conveys the refrigerant to the compressor, the refrigerant being circulated through the compressor, the condenser, the capillary tube, the evaporator, and the cooling unit in this order, the capillary tube having a length of 30 cm and an outer diameter of 2.5-2.7 mm, and the compressor having a number of revolutions per minute of less than 700 rpm.

Description

Technical Field

[0001] The present invention relates to a battery-driven low-power air conditioner for vehicles, and more particularly, to a battery-driven low-power air conditioner for vehicles that can minimize power consumption and improve refrigeration performance. Background Art

[0002] As the refrigerant flows through the condenser, expansion valve, evaporator, compressor, etc., the air conditioner can absorb heat from the indoor air using the latent heat of evaporation of the refrigerant.

[0003] In the case of a general vehicle air conditioner, the compressor varies in proportion to the engine speed, so the range of change in the rotational speed (RPM) of the compressor is very large.

[0004] Therefore, in order to achieve optimal air conditioner performance according to the speed change, it is not preferable to use a fixed expansion valve. For this, in order to ensure that the evaporator has an appropriate superheat degree without being affected by the speed change, that is, in order to obtain the best evaporator performance, a superheat control type expansion valve (TXV) is adopted.

[0005] The above-mentioned superheat control type expansion valve (TXV) is characterized in that in the low speed range, an appropriate superheat degree can be maintained by making the refrigerant flow rate smaller than the fixed type, and in the high speed range, an appropriate superheat degree can be continuously maintained by making the refrigerant flow rate larger than the fixed type.

[0006] However, since the existing general vehicle air conditioner needs to drive the engine, there are problems of increased fuel consumption and air pollution.

[0007] In order to solve the above problems, currently, a non-start air conditioner for vehicles that can be driven by a vehicle battery without driving the vehicle engine has been developed. Figure 1 The diagram of the existing non-start air conditioner for vehicles.

[0008] As Figure 1 shown, the existing non-start air conditioner for vehicles consists of two independently driven refrigerant cycles. This is because the method of increasing the refrigerant amount in a single refrigerant cycle to improve the refrigeration performance not only has a limited degree problem, but also, as the refrigerant amount increases, it burdens the air conditioner and may cause the cooling performance to decrease instead.

[0009] Therefore, the existing non-start air conditioner for vehicles needs to be equipped with two compressors that can improve the refrigeration performance without increasing the refrigerant amount and can operate the refrigerant cycles independently. Thus, two condensers, capillary tubes, and evaporators need to be included respectively.

[0010] However, although the refrigeration performance has been improved, with the increase in power consumption, the existing non-actuated vehicle air conditioner composed of two refrigerant cycles has the risk of reduced air conditioner usage time and battery discharge.

[0011] Prior art documents

[0012] Patent Document 1: Korean Patent Publication No. 10-0882518 (February 9, 2009)

[0013] Patent Document 2: Korean Patent Publication No. 10-1251206 (April 8, 2013) Summary of the Invention

[0014] Technical Problem

[0015] In order to solve the above problems, an object of the present invention is to provide a battery-driven low-power air conditioner for vehicles under optimal conditions, that is, it can minimize power consumption and maximize refrigeration performance.

[0016] Technical Solution

[0017] In order to achieve the above object, the battery-driven low-power air conditioner for vehicles of the present invention includes: a compressor for compressing and discharging a refrigerant; an electric motor for providing a rotational force to the compressor; a battery for supplying power to the electric motor; a speed reducer for connecting the electric motor and the compressor with a reduction ratio of 3:1; a condenser for condensing the high-pressure refrigerant discharged from the compressor; a capillary tube for depressurizing the refrigerant liquefied by the condenser to pass through; an evaporator for vaporizing the refrigerant passing through the capillary tube through heat exchange with steam heat; and a cooling unit for cooling the electric motor with the refrigerant received from the evaporator and then delivering the refrigerant to the compressor. The refrigerant circulates in the compressor, condenser, capillary tube, evaporator, and cooling unit in sequence. The length of the capillary tube is 30 cm, the outer diameter is 2.5 mm to 2.7 mm, and the number of revolutions per minute of the compressor is less than 700 rpm.

[0018] The power of the electric motor is 270 W to 330 W, the number of revolutions per minute of the compressor is 400 rpm to 450 rpm, and when the voltage of the battery is 48 V, the current consumption of the electric motor is 10 A or less.

[0019] The refrigerant is R134a, the total amount of the refrigerant is 250 g, the compressor is a vane compressor, and the size of the compression chamber for accommodating the refrigerant to compress the refrigerant is 108 cc.

[0020] The above cooling unit is composed of a cooling plate and a refrigerant delivery pipe. The cooling plate is bent to surround the side surface of the electric device and at least contact four surfaces of the electric device. The refrigerant delivery pipe is attached to the cooling plate and has an inlet end and an outlet end that cross - contact each other. The inlet end is for the refrigerant to flow in from the evaporator, and the outlet end is for the refrigerant to flow out to the compressor. The refrigerant passing through the refrigerant delivery pipe exchanges heat with the electric device via the cooling plate, and the heat exchange is completed at the cross - section of the inlet end and the outlet end.

[0021] Effects of the Invention

[0022] The battery - powered low - power consumption air conditioner for vehicles of the present invention can not only minimize power consumption to the greatest extent, but also improve the refrigeration performance by enhancing the refrigeration efficiency. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of an existing non - starting air - conditioning system for vehicles.

[0024] Figure 2 It is a schematic diagram of the battery - powered low - power consumption air - conditioning system for vehicles according to the first embodiment of the present invention.

[0025] Figure 3 It is a structural diagram of the vane compressor according to the first embodiment of the present invention.

[0026] Figure 4 It is a perspective view of the cooling unit according to the first embodiment of the present invention.

[0027] Figure 5 It is a diagram showing the capillary tube in the battery - powered low - power consumption air - conditioning system for vehicles according to the first embodiment of the present invention connected in an exposed state.

[0028] Figure 6 It is a schematic diagram of the capillary tube self - sub - cooling protection device and its connection method in the battery - powered low - power consumption air - conditioning system for vehicles according to the second embodiment of the present invention. Detailed Description of the Invention

[0029] The following describes the first embodiment of the present invention.

[0030] As Figures 2 to 5 shown, the battery - powered low - power consumption air conditioner for vehicles in the first embodiment is composed of a compressor 10, an electric device 20, a speed reducer (not shown), a battery (not shown), a condenser 30, a capillary tube 40, an evaporator 50, and a cooling unit 60. In this case, the refrigerant circulates in the compressor 10, the condenser 30, the capillary tube 40, the evaporator 50, and the cooling unit 60 in sequence.

[0031] The compressor 10 compresses and discharges the refrigerant by the rotational force of the electric motor 20. The electric motor 20 provides the rotational force to the compressor 10, and the battery supplies power to the electric motor 20. In this case, the reduction gear connects the electric motor 20 and the compressor 10 at a reduction ratio of 3:1. The high rotational speed of 1200 rpm generated from the electric motor 20 is reduced by the reduction gear to maintain the torque force required for the compressor 10. The condenser 30 condenses the high-pressure refrigerant discharged from the compressor 10. The capillary tube 40 is located between the condenser 30 and the evaporator 50, and the refrigerant liquefied by the condenser 30 is depressurized through the capillary tube 40. The evaporator 50 vaporizes the refrigerant passing through the capillary tube 40 through heat exchange with the steam heat. The cooling unit 60 receives the refrigerant from the evaporator 50, cools the electric motor 20, and then delivers the refrigerant to the compressor 10.

[0032] Hereinafter, the vehicle-mounted battery-driven low-power air conditioner according to the present embodiment will be described in further detail.

[0033] As Figure 3 shown, the compressor 10 of the embodiment of the present invention is a vane 16 type compressor 10. The compressor 10 is composed of a housing 13, a rotor 14, a shaft 15, and a plurality of vanes 16. An intake port 11 for sucking the refrigerant and a discharge port 12 for discharging the refrigerant are formed in the housing 13. The rotor 14 rotates inside the housing 13. The shaft 15 connects the rotor 14 to the electric motor 20 and transmits the rotational force of the electric motor 20 to the rotor 14. The plurality of vanes 16 are combined with the rotor 14 in a floating manner and are in close contact with the inner wall of the housing 13. A compression chamber 17 into which the refrigerant flows and is compressed is formed between the vanes 16. The refrigerant capacity accommodated in one compression chamber 17 is 108 cc. Moreover, the refrigerant is R134a, and the total amount of the refrigerant circulating in the refrigeration system of the present invention is 250 g. In the case where the refrigerant amount reaches the critical value, although the refrigeration performance can be improved, however, as the power consumption increases, since the improvement efficiency of the refrigeration performance is lower than the increase amount of the refrigerant, it is not preferable. On the contrary, in the case where the refrigerant amount is small, it will be difficult to sufficiently maintain the refrigeration performance.

[0034] The electric device 20 is a brushless direct current motor that uses direct current. The electric device 20 is connected to the shaft 15 through a speed reducer and rotates the rotor 14, and its power is 1 / 3 of the appropriate power required by the compressor 10. In the embodiment of the present invention, if the appropriate power required by the compressor 10 is 900W, the power of the electric device 20 used to drive the compressor 10 is 300W. That is, the present invention can minimize power consumption by using an electric device 20 with a lower power than the appropriate power required by the compressor 10. Such an electric device 20 can operate within a power range of 270W to 330W. However, in this case, since the electric device 20 with a power lower than the appropriate power required by the compressor 10 is used, there is a possibility of overload in the electric device 20. To prevent such overload, the present invention includes a cooling unit 60 for cooling the electric device 20 in the refrigeration system without adding a cooling device externally.

[0035] Under normal circumstances, in order to achieve sufficient refrigeration performance in a vehicle, the rotational speed of the compressor 10 needs to reach 700 rpm or more. When the number of revolutions per minute of the compressor 10 is relatively high, although the refrigeration performance can be improved, there is a problem of increased power consumption due to the need for a higher-power electric device 20. Since improving the performance of the electric device 20 and the compressor 10 and increasing power consumption do not conform to the purpose of the present invention, the number of revolutions per minute of the 48V electric device 20 is maintained at 1200 rpm. If a 3:1 speed reducer is used, it becomes 666 rpm, which is close to the rotational force for the compressor 10. Among them, as the electric energy lost due to the heat of the motor is reduced by the cooling unit 60 for cooling the electric device 20, the number of revolutions per minute of the compressor 10 connected to the electric device 20 drops to 60% of the level from 400 rpm to 666 rpm. That is, the compressor 10 rotates at 400 rpm through the electric device 20 and the speed reducer. According to the deviation during actual operation, the compressor 10 rotates within the range of 400 rpm to 450 rpm. The top priority objective of the present invention is to provide the best air-conditioning structure that can minimize power consumption and maximize refrigeration performance and disclose the shape limitation matters of the capillary tube 40. In the present invention, when the voltage of the storage battery is 48V, the current consumption of the electric device 20 can be maintained below 10A.

[0036] In the present invention, in order to minimize power consumption and stably maintain high refrigeration performance, the outer diameter of the capillary tube 40 is determined to be 2.6 mm, and the length is determined to be 30 cm. As described above, when the length of the capillary tube 40 is increased based on the determined capillary tube 40, although the refrigeration performance is improved, the low power consumption condition cannot be satisfied due to the increase in power consumption. Moreover, when the length of the capillary tube 40 is shortened based on the determined capillary tube 40, although the power consumption can be reduced, the refrigeration performance will also decrease accordingly.

[0037] On the other hand, if a variable expansion valve for a general vehicle air conditioner is used instead of the capillary tube 40, the hydraulic pressure of the refrigerant changes with the temperature, resulting in a change in the discharge amount of the refrigerant. Therefore, for a vehicle air conditioner using a variable expansion valve, there is also a risk that the current consumption increases with the temperature rise, the air conditioner usage time decreases, and the battery discharges.

[0038] As Figure 4 shown, the cooling unit 60 is composed of a cooling plate 61 and a refrigerant delivery pipe 62. The cooling plate 61 is bent to surround the side surface of the electric actuator 20 and contacts at least four surfaces of the electric actuator 20. The refrigerant delivery pipe 62 is attached to the cooling plate 61, and is formed with an inflow end 63 for the refrigerant to flow in from the evaporator 50 and an outflow end 64 for the refrigerant to flow out to the compressor 10. The inflow end 63 and the outflow end 64 are in cross contact with each other. The above-mentioned cooling unit 60 enables the refrigerant passing through the refrigerant delivery pipe 62 to exchange heat with the electric actuator 20 via the cooling plate 61, and the above-mentioned heat exchange is completed at the cross portion of the inflow end 63 and the outflow end 64. With the realization of the heat exchange between the refrigerant passing through the refrigerant delivery pipe 62 and the electric actuator 20, the electric actuator 20 can be prevented from being overloaded and a low-power electric actuator 20 can be used. Moreover, when the refrigerant is delivered to the compressor 10 through the outflow end 64, with the outflow end 64 contacting the inflow end 63, the heat exchange of the refrigerant can be realized again. That is, heat exchange is realized between the refrigerant at the outflow end 64 that is relatively heated due to heat exchange with the electric actuator 20 and the refrigerant at the inflow end 63 before heat exchange with the electric actuator 20, thereby reducing the temperature of the refrigerant delivered to the compressor 10. As the temperature of the refrigerant delivered to the compressor 10 is reduced, the pressure at which the compressor 10 sucks in the refrigerant will also be reduced accordingly. Generally, in a refrigeration system, the lower the pressure sucked in through the suction port 11 of the compressor 10, the more advantageous it is.

[0039] Table 1 is a table comparing the suction pressure and discharge pressure of the compressor 10 according to the outer diameter of the capillary tube 40 under the structure and conditions of the above-mentioned vehicle air conditioner.

[0040] Table 1

[0041]

[0042] In the compressor 10, the lower the suction pressure, the more beneficial it is to the refrigeration performance. Moreover, the higher the discharge pressure, the greater the burden on the compressor 10. As shown in Table 1, it can be seen that the smaller the outer diameter of the capillary 40, the lower the suction pressure and the discharge pressure. Table 2 is a table comparing the indoor and outdoor temperatures according to the outer diameter of the capillary 40 under the above-mentioned structure and conditions of the vehicle air conditioner.

[0043] Table 2

[0044]

[0045] The indoor temperature refers to the temperature of the refrigerated air supplied to the room through the evaporator 50. As shown in Table 2, it can be seen that under the same outdoor temperature conditions, the smaller the outer diameter of the capillary 40, the lower the indoor temperature and the better the refrigeration performance. However, when the outer diameter of the capillary 40 is 2.4 mm, the refrigeration performance decreases instead as the indoor temperature increases. In summary, according to the experimental examples in Table 1 and Table 2, it can be confirmed that the best refrigeration performance is exhibited when the length of the capillary 40 is 30 cm and the outer diameter of the capillary 40 is 2.6 mm. If the outer diameter of the capillary 40 is reduced to 2.4 mm or increased to 2.8 mm, the refrigeration performance will be reduced. Finally, when the above-mentioned limiting conditions are satisfied simultaneously, the vehicle battery-driven low-power air conditioner of the present invention can minimize power consumption and maximize refrigeration performance.

[0046] The following describes the second embodiment of the present invention.

[0047] Figure 5 FIG. for showing the exposed connection state of the capillary in the first embodiment, Figure 6 FIG. for showing the capillary subcooling protection device in the second embodiment connected using a rubber hose.

[0048] As Figure 6 shown, the capillary self-subcooling protection device of the vehicle battery-driven low-power air conditioner according to the second embodiment of the present invention includes: an outlet-side pipe contact portion 32 of the condenser 30; a subcooling protection hose 42 composed of the capillary 40 and a rubber hose surrounding the capillary; and an inlet-side pipe contact portion 52 of the evaporator 50. In this case, the refrigerant flows from the pipe of the condenser 30 through the capillary 40 into the evaporator 50, and at the same time fills and flows through the capillary subcooling protection hose 42.

[0049] The inherent feature of the connection is that:

[0050] (1) On the condenser 30 side, after sealing and connecting the piping of the condenser 30 and the capillary tube 40 by welding, the capillary tube 40 is covered with a subcooling protection hose 42 to prevent refrigerant leakage. Therefore, the refrigerant only moves through the capillary tube 40. In this case, the inlet end of the 60 mm capillary tube 40 is inserted into the piping on the condenser 30 side for welding.

[0051] (2) On the evaporator 50 side, the subcooling protection hose 42 is connected in such a way that only the piping connection mechanism of the evaporator 50 is sealed, so that the internal space of the subcooling protection hose 42 is in communication with the internal space of the evaporator 50. Thus, the refrigerant flowing out of the outlet of the capillary tube 40 fills and flows through the inside of the subcooling protection hose 42 and flows into the evaporator 50. In this case, the outlet end of the 20 mm capillary tube 40 is inserted into the connection port on the evaporator 50 side.

[0052] At this time, the subcooled refrigerant flowing out of the condenser 30 fills and flows through the inside of the subcooling protection hose 42 of the capillary tube 40. Thus, the refrigerant inside the capillary tube 40 is subcooled and protected from the heat source of the external air. Therefore, the subcooling of the refrigerant flowing in from the condenser can be ensured.

[0053] Table 1 is a table comparing the suction pressure and discharge pressure of the compressor according to the outer diameter of the capillary tube of the vehicle battery-driven low-power air conditioner according to the first embodiment. Among them, according to the first embodiment, when the outer diameter of the capillary tube 40 is 2.6 mm, the capillary tube exhibits the best refrigeration performance. Therefore, as the capillary tube self-subcooling protection device of the present invention, a capillary tube with an outer diameter of 2.6 mm is also used for performance comparison.

[0054] Table 3 shows the pressure of the compressor 10 when using the capillary tube self-subcooling protection device of the second embodiment. As shown in Table 3, when using the capillary tube self-subcooling protection device, although the discharge pressure slightly increases, the suction pressure decreases.

[0055] Table 3

[0056]

[0057] Table 2 is a table comparing the indoor and outdoor temperatures according to the outer diameter of the capillary 40 of the battery-driven low-power air conditioner for vehicles according to the first embodiment. Among them, according to the first embodiment, when the outer diameter of the capillary 40 is 2.6 mm, the capillary 40 exhibits the best refrigeration performance. Therefore, as the capillary self-subcooling protection device of the present invention, the capillary 40 with an outer diameter of 2.6 mm is also used for performance comparison. Table 4 shows the indoor and outdoor temperatures when the capillary self-subcooling protection device of the second embodiment is used for the capillary 40 with an outer diameter of 2.6 mm. As shown in Table 4, in the case of the first embodiment, when the outdoor temperature is 28.5 degrees, the indoor temperature reaches 8.9 degrees. However, when the capillary self-subcooling protection device is used, it can be seen that the indoor temperature significantly drops to 5.5 degrees at which the refrigeration effect can be determined.

[0058] Table 4

[0059]

[0060] In summary, according to the experimental examples in Table 3 and Table 4, in the air conditioner that exhibits the best refrigeration performance when the length of the capillary 40 is 30 cm and the outer diameter of the capillary 40 is 2.6 mm, when a subcooling protection device with an outer diameter of 16 mm, an inner diameter of 9.5 mm, and a length of 220 mm is used, the refrigeration performance can be further improved. As a result, as the subcooled refrigerant flowing out from the condenser 30 fills and flows through the inside of the subcooling protection hose 42 of the capillary 40, the refrigerant inside the capillary 40 is subcooled and protected from the heat source of the external air, so that the subcooling of the refrigerant flowing into the condenser 30 can be effectively ensured.

[0061] The battery-driven low-power air conditioner for vehicles of the present invention is not limited to the above two embodiments, and various modifications can be implemented within the scope allowed by the technical idea of the present invention.

Claims

1. A battery-driven low-power air conditioner for vehicles, Characterized in that, Comprising: A compressor for compressing and discharging a refrigerant; An electric motor for providing a rotational force to the above-mentioned compressor; A battery for supplying power to the above-mentioned electric motor; A speed reducer for connecting the above-mentioned electric motor and the compressor with a reduction ratio of 3:1; A condenser for condensing the high-pressure refrigerant discharged from the above-mentioned compressor; A capillary tube through which the refrigerant liquefied by the above-mentioned condenser passes under reduced pressure; An evaporator for vaporizing the refrigerant passing through the above-mentioned capillary tube through heat exchange with steam heat; and A cooling section for cooling the above-mentioned electric motor with the refrigerant received from the above-mentioned evaporator and then delivering the refrigerant to the above-mentioned compressor, The above-mentioned refrigerant circulates successively in the above-mentioned compressor, condenser, capillary tube, evaporator, and cooling section. The length of the above-mentioned capillary tube is 30 cm, and the outer diameter is 2.5 mm to 2.7 mm. The power of the above-mentioned electric motor is 270 W to 330 W, and the number of revolutions per minute of the above-mentioned compressor is 400 rpm to 450 rpm. When the voltage of the above-mentioned battery is 48 V, the current consumption of the above-mentioned electric motor is 10 A or less. The above-mentioned compressor is a vane compressor, which consists of a housing, a rotor, a shaft, and a plurality of vanes. An intake port for sucking the refrigerant and a discharge port for discharging the refrigerant are formed in the above-mentioned housing. The above-mentioned rotor rotates inside the above-mentioned housing. The above-mentioned shaft connects the above-mentioned rotor to the electric motor and transmits the rotational force of the above-mentioned electric motor to the above-mentioned rotor. The above-mentioned plurality of vanes are connected to the above-mentioned rotor in a floating manner and are in close contact with the inner wall of the above-mentioned housing. A compression chamber into which the refrigerant flows and is compressed is formed between the above-mentioned vanes. The total amount of the above-mentioned refrigerant is 250 g, and the size of the compression chamber for accommodating the refrigerant for compressing the refrigerant is 108 cc. The above-mentioned electric motor is connected to the above-mentioned shaft through the above-mentioned speed reducer and rotates the above-mentioned rotor. The above-mentioned cooling section consists of a cooling plate and a refrigerant delivery pipe. The above-mentioned cooling plate is bent to surround the side surface of the above-mentioned electric motor and contacts at least four surfaces of the above-mentioned electric motor. The above-mentioned refrigerant delivery pipe is attached to the above-mentioned cooling plate and is formed with an inlet end and an outlet end that cross and contact each other. The above-mentioned inlet end is used for the refrigerant to flow in from the above-mentioned evaporator, and the above-mentioned outlet end is used for the refrigerant to flow out to the above-mentioned compressor. The refrigerant passing through the above-mentioned refrigerant delivery pipe exchanges heat with the above-mentioned electric motor through the above-mentioned cooling plate, and the heat exchange is completed at the cross-section of the above-mentioned inlet end and the above-mentioned outlet end.

2. The battery-driven low-power air conditioner for vehicles according to claim 1, Characterized in that, Comprising: The outlet side pipe contact part of the above-mentioned condenser; A subcooling protection hose composed of the above-mentioned capillary tube and a rubber hose surrounding the above-mentioned capillary tube; and The inlet side pipe contact part of the above-mentioned evaporator, The above-mentioned refrigerant flows from the condenser pipe through the above-mentioned capillary tube into the above-mentioned evaporator, and also fills and flows through the above-mentioned subcooling protection hose.

3. The battery-driven low-power air conditioner for vehicles according to claim 2, Characterized in that, On the condenser side, after sealing and connecting the pipe of the condenser in parallel and the capillary tube by welding, the capillary tube is covered with the subcooling protection hose to prevent refrigerant leakage. Among them, the inlet end of the capillary tube of 60 mm is inserted into the pipe on the condenser side for welding. On the evaporator side, the subcooling protection hose is connected in such a way that only the pipe connection mechanism of the evaporator is sealed, so that the internal space of the subcooling protection hose is in communication with the internal space of the evaporator. The refrigerant flowing out from the outlet of the capillary tube fills and flows through the inside of the subcooling protection hose and then flows into the evaporator. Among them, the outlet end of the capillary tube of 20 mm is inserted into the connection port of the evaporator.

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