阅读说明：本技术 一种双压缩机的电动汽车热管理系统 (Electric automobile thermal management system with double compressors ) 是由 陈海涛 吴靖 于吉乐 任亚超 于 2021-05-12 设计创作，主要内容包括：本发明提供了一种双压缩机的电动汽车热管理系统,包括：二氧化碳热管理模块和第二工质热管理模块,所述二氧化碳热管理模块用于驾驶舱制热和动力电池冷却,所述第二工质热管理模块用于驾驶舱制冷。本发明采用的双压缩机的设计彻底解决了二氧化碳制冷剂夏季驾驶舱制冷效率低下的问题,因为在驾驶舱制冷循环中主要使用了传统的制冷工质。(The invention provides a double-compressor electric automobile thermal management system, which comprises: the device comprises a carbon dioxide heat management module and a second working medium heat management module, wherein the carbon dioxide heat management module is used for heating a cockpit and cooling a power battery, and the second working medium heat management module is used for refrigerating the cockpit. The design of the double compressors adopted by the invention thoroughly solves the problem that the refrigerating efficiency of the carbon dioxide refrigerant in the cockpit is low in summer, because the traditional refrigerating working medium is mainly used in the refrigerating cycle of the cockpit.)

1. A dual-compressor electric vehicle thermal management system, comprising: the device comprises a carbon dioxide heat management module and a second working medium heat management module, wherein the carbon dioxide heat management module is used for heating a cockpit and cooling a power battery, and the second working medium heat management module is used for refrigerating the cockpit.

2. The dual-compressor electric vehicle thermal management system of claim 1, wherein: the carbon dioxide heat management module comprises a carbon dioxide compressor, a carbon dioxide loop water-cooled gas cooler, a carbon dioxide loop heat regenerator, a carbon dioxide loop electronic expansion valve, a carbon dioxide loop water-cooled evaporator and a carbon dioxide gas-liquid separator;

the outlet of the carbon dioxide compressor is communicated with the inlet of the carbon dioxide compressor after being sequentially connected with the carbon dioxide loop water-cooling gas cooler, the carbon dioxide loop heat regenerator, the carbon dioxide loop electronic expansion valve, the carbon dioxide loop water-cooling evaporator, the carbon dioxide gas-liquid separator and the carbon dioxide loop heat regenerator through pipelines.

3. The dual-compressor electric vehicle thermal management system of claim 2, wherein: the carbon dioxide cooling water heat dissipation module comprises an air water heater, a stop valve, a first three-way water valve, a first air radiator, a first water pump, a fourth three-way water valve and a second water pump; and a cooling water outlet of the carbon dioxide loop water-cooling gas cooler is communicated with a cooling water inlet of the carbon dioxide loop water-cooling gas cooler after being sequentially connected with the air water heater, the stop valve, the first three-way water valve, the first air radiator, the second water pump, the fourth three-way water valve and the first water pump through pipelines.

4. The dual-compressor electric vehicle thermal management system of claim 2, wherein: still include battery heat dissipation module, battery heat dissipation module includes third water pump, third tee bend water valve, power battery heat pipe and the three-way water valve of second, the cooling water export of carbon dioxide return circuit water-cooled evaporator communicates with the cooling water entry of carbon dioxide return circuit water-cooled evaporator behind second tee bend water valve, power battery heat pipe, the three-way water valve of third, the third water pump in proper order through the pipeline and is linked together.

5. The dual-compressor electric vehicle thermal management system of claim 4, wherein: the solar water heater further comprises a charging unit and an inverter radiator, a motor and control radiator and a second air radiator, wherein the charging unit and the inverter radiator are sequentially connected with the motor and control radiator, a third water pump, a carbon dioxide loop water-cooling evaporator, a second three-way water valve and the second air radiator through pipelines to form a heat dissipation loop.

6. The dual-compressor electric vehicle thermal management system of claim 2, wherein: the second working medium heat management module comprises a second working medium compressor, a second working medium water-cooling condenser, a second working medium thermal expansion valve and a second working medium evaporator, wherein the outlet of the second working medium compressor is communicated with the inlet of the second working medium compressor after being sequentially connected with the second working medium water-cooling condenser, the second working medium thermal expansion valve and the second working medium evaporator through pipelines.

7. The dual-compressor electric vehicle thermal management system of claim 6, wherein: and a condensed water inlet of the second working medium water-cooled condenser is communicated with a second water pump, and a condensed water outlet of the second working medium water-cooled condenser is communicated with a first three-way water valve.

8. The dual-compressor electric vehicle thermal management system of claim 3, wherein: and a pipeline between the first three-way water valve and the stop valve is communicated with a fourth three-way water valve.

9. The dual-compressor electric vehicle thermal management system of claim 8, wherein: and a one-way water valve is communicated between the power battery heat pipe and the second three-way water valve, and the other end of the one-way water valve is connected with a pipeline between the fourth three-way water valve and the stop valve.

10. The dual-compressor electric vehicle thermal management system of claim 6, wherein: the second working medium compressor and the carbon dioxide compressor are driven by the same rotary driving part, and the rotary driving part controls one compressor or two compressors to work simultaneously through the clutch.

Technical Field

The invention relates to the field of electric automobile thermal management, in particular to a dual-compressor electric automobile thermal management system.

Background

Since carbon dioxide refrigerant has an extremely low GWP (global warming potential) value, it has received much attention from the automobile thermal system industry in recent years, and a part of vehicle models using carbon dioxide refrigerant have been mass-produced. For electric vehicles, carbon dioxide refrigerant is very suitable for application as a heat pump refrigerant because of its extremely high low-temperature heating capacity. However, since the carbon dioxide refrigerant is in a supercritical state in a high-pressure section, heat loss is large during the throttle expansion of the vapor compression cycle, and thus the refrigerating capacity and efficiency of the carbon dioxide refrigerant are significantly reduced compared to the conventional R134a or R1234yf refrigerant at a high ambient temperature. At present, an intermediate heat exchanger or a jet refrigeration mode is generally adopted to improve the refrigeration performance. However, the two methods can only improve the refrigeration performance to a certain degree, and cannot completely achieve the effect of the traditional refrigerant.

In the chinese patent application publication No. CN109515115A, an automotive air conditioning system and a control method using carbon dioxide as a working medium are disclosed, which relate to the technical field of automotive air conditioners. The invention comprises an HVAC air conditioning box, a refrigerant circulation path and a control system, wherein the refrigerant is carbon dioxide, the air conditioning system is configured to switch among the refrigerant circulation path in a heating mode, the refrigerant circulation path in a dehumidification heating mode, the refrigerant circulation path in a conventional cooling mode and the refrigerant circulation path in an injection cooling mode, and can improve the cooling energy efficiency of the carbon dioxide automobile air conditioner, realize the best energy efficiency of the carbon dioxide system, improve the suction superheat degree and the operation reliability of a compressor, avoid slow cooling caused by using an injector and avoid the reduction of cooling or heating performance when the flow of the refrigerant is reduced. Ejector technology, however, presents design optimization and control difficulties and is currently not mature in the field of automotive air conditioning.

In the US patent publication No. US2003000235a1, an air conditioning system for a vehicle operating with carbon dioxide is disclosed, which has a high pressure part connected to the output of a compressor and including a gas cooler, and a low pressure part connected to the suction side of the compressor and including an evaporator, and an expansion member connecting the high pressure part and the low pressure part. The expansion member has a fixed flow restrictor with an orifice of predetermined length and diameter connected between the inlet of the high pressure section and the outlet of the low pressure section so that the pressure in the refrigerant is at a value limited to less than 14MPa in the high pressure portion of the system under all operating conditions of the system. The flow restrictor may be connected in parallel with the pressure limiting valve and may include two or more different orifices that may be selectively connected for refrigerant flow. However, the use of the intermediate heat exchanger cannot fundamentally solve the problem of insufficient refrigeration performance of carbon dioxide, and simultaneously, the exhaust temperature of the compressor can be increased, which is not favorable for the overall performance of the system.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a dual-compressor electric automobile thermal management system.

The invention provides a double-compressor electric automobile thermal management system, which comprises: the device comprises a carbon dioxide heat management module and a second working medium heat management module, wherein the carbon dioxide heat management module is used for heating a cockpit and cooling a power battery, and the second working medium heat management module is used for refrigerating the cockpit.

Preferably, the carbon dioxide heat management module comprises a carbon dioxide compressor, a carbon dioxide loop water-cooling gas cooler, a carbon dioxide loop heat regenerator, a carbon dioxide loop electronic expansion valve, a carbon dioxide loop water-cooling evaporator and a carbon dioxide gas-liquid separator;

the outlet of the carbon dioxide compressor is communicated with the inlet of the carbon dioxide compressor after being sequentially connected with the carbon dioxide loop water-cooling gas cooler, the carbon dioxide loop heat regenerator, the carbon dioxide loop electronic expansion valve, the carbon dioxide loop water-cooling evaporator, the carbon dioxide gas-liquid separator and the carbon dioxide loop heat regenerator through pipelines.

Preferably, the system also comprises a carbon dioxide cooling water heat dissipation module, wherein the carbon dioxide cooling water heat dissipation module comprises an air water heater, a stop valve, a first three-way water valve, a first air radiator, a first water pump, a fourth three-way water valve and a second water pump; and a cooling water outlet of the carbon dioxide loop water-cooling gas cooler is communicated with a cooling water inlet of the carbon dioxide loop water-cooling gas cooler after being sequentially connected with the air water heater, the stop valve, the first three-way water valve, the first air radiator, the second water pump, the fourth three-way water valve and the first water pump through pipelines.

Preferably, still include battery heat dissipation module, battery heat dissipation module includes third water pump, third tee bend water valve, power battery heat pipe and the three-way water valve of second, the cooling water export of carbon dioxide return circuit water-cooled evaporator communicates with the cooling water entry of carbon dioxide return circuit water-cooled evaporator behind second tee bend water valve, power battery heat pipe, the three-way water valve of third, the third water pump in proper order through the pipeline and is linked together.

Preferably, the system also comprises a charging unit, an inverter radiator, a motor and control radiator and a second air radiator, wherein the charging unit and the inverter radiator are sequentially connected with the motor and control radiator, a third water pump, a carbon dioxide loop water-cooling evaporator, a second three-way water valve and the second air radiator through pipelines and then are connected with the charging unit and the inverter radiator to form a heat radiation loop.

Preferably, the second working medium heat management module comprises a second working medium compressor, a second working medium water-cooled condenser, a second working medium thermal expansion valve and a second working medium evaporator, and an outlet of the second working medium compressor is communicated with an inlet of the second working medium compressor after being sequentially connected with the second working medium water-cooled condenser, the second working medium thermal expansion valve and the second working medium evaporator through pipelines.

Preferably, a condensed water inlet of the second working medium water-cooled condenser is communicated with a second water pump, and a condensed water outlet of the second working medium water-cooled condenser is communicated with the first three-way water valve.

Preferably, a pipeline between the first three-way water valve and the stop valve is communicated with a fourth three-way water valve.

Preferably, a one-way water valve is communicated between the power battery heat pipe and the second three-way water valve, and the other end of the one-way water valve is connected with a pipeline between the fourth three-way water valve and the stop valve.

Preferably, the second working medium compressor and the carbon dioxide compressor are driven by the same rotary driving part, and the rotary driving part controls one compressor or two compressors to work simultaneously through a clutch.

Compared with the prior art, the invention has the following beneficial effects:

1. the design of the dual compressor thoroughly solves the problem of low refrigeration efficiency of the carbon dioxide refrigerant in the cockpit in summer, because the traditional refrigerant cycle is mainly used in the refrigeration cycle of the cockpit.

2. The system comprises a cooling liquid loop, and can realize cooling and heating of the power battery and cooling and waste heat recovery of the motor electric control system. The battery heating is realized through heat pump circulation, an electric heater is not needed, energy is saved, efficiency is high, and cost of the electric heater is saved.

3. The system refrigerant circuit uses a dual compressor design. One of the compressors uses carbon dioxide refrigerant and is mainly used for heating circulation of a cockpit and cooling of a power battery of an automobile; the other compressor uses a conventional refrigerant and is primarily used in the cockpit refrigeration cycle. The two compressors are driven by the same motor, and the operation of one compressor or the simultaneous operation of the two compressors is controlled by a clutch. Because 2 compressor systems can work independently and each plays its own role, each system can be made simply, and the reliability of the system is improved.

4. Since 2 compressors are used, the displacement of each compressor need not be excessive.

5. The design scheme of the double-compressor system solves the problem that the cost of the conventional electric compressor is high.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural diagram of a dual-compressor electric vehicle thermal management system according to an embodiment of the present application;

FIG. 2 is a schematic view illustrating the operation of a dual-compressor thermal management system of an electric vehicle in a cockpit cooling mode according to an embodiment of the present application;

FIG. 3 is a schematic diagram illustrating operation of a dual-compressor thermal management system of an electric vehicle in a cockpit and power cell simultaneous cooling mode according to an embodiment of the present disclosure;

FIG. 4 is a schematic view illustrating the operation of a thermal management system of an electric vehicle with two compressors in a heating mode of a cockpit according to an embodiment of the present application;

FIG. 5 is a schematic diagram illustrating operation of a dual-compressor thermal management system of an electric vehicle in a heating mode required by both a cockpit and a power battery according to an embodiment of the present application;

fig. 6 is a schematic diagram illustrating the operation of the thermal management system of the electric vehicle with two compressors according to the embodiment of the present application in the cabin dehumidification and heating mode.

Reference numerals:

1. a carbon dioxide compressor; 2. a carbon dioxide loop water-cooled gas cooler; 3. a carbon dioxide loop regenerator; 4. a carbon dioxide loop electronic expansion valve; 5. a carbon dioxide loop water-cooled evaporator; 6. a carbon dioxide gas-liquid separator; 7. a second working medium compressor; 8. a second working medium water-cooling condenser; 9. a second working medium thermal expansion valve; 10. a second working medium evaporator; 11. an air-water heater; 12. a third three-way water valve; 13. a third water pump; 14. a stop valve; 15. a power battery heat pipe; 16. a one-way water valve; 17. a second three-way water valve; 18. a first three-way water valve; 19. a first air radiator; 20. a second air radiator; 21. a second water pump; 22. a fourth three-way water valve; 23. a first water pump; 24. a charging unit and an inverter radiator; 25. driving motor and control module radiator.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

The invention provides an electric automobile heat management system, which comprises a carbon dioxide heat management module and a second working medium heat management module, and as shown in figure 1, the system mainly comprises a carbon dioxide compressor 1, a carbon dioxide loop water-cooled gas cooler 2, a carbon dioxide loop heat regenerator 3, a carbon dioxide loop electronic expansion valve 4, a carbon dioxide loop water-cooled evaporator 5, a carbon dioxide gas-liquid separator 6, a second working medium compressor 7, a second working medium water-cooled condenser 8, a second working medium thermal expansion valve 9, a second working medium evaporator 10, an air water heater 11, a third three-way water valve 12, a third water pump 13, a stop valve 14, a power battery heat pipe 15, a one-way water valve 16, a second three-way water valve 17, a first three-way water valve 18, a first air radiator 19, a second air radiator 20, a second water pump 21, a fourth three-way water valve 22, a first water pump 23, a second water pump 23, a third water pump and a third water pump, A charging unit and inverter radiator 24, a drive motor and its control module radiator 25.

The carbon dioxide heat management module comprises a carbon dioxide compressor 1, a carbon dioxide loop water-cooling gas cooler 2, a carbon dioxide loop heat regenerator 3, a carbon dioxide loop electronic expansion valve 4, a carbon dioxide loop water-cooling evaporator 5 and a carbon dioxide gas-liquid separator 6. The outlet of the carbon dioxide compressor 1 is connected with the carbon dioxide loop water-cooling gas cooler 2, the carbon dioxide loop heat regenerator 3, the carbon dioxide loop electronic expansion valve 4, the carbon dioxide loop water-cooling evaporator 5, the carbon dioxide gas-liquid separator 6 and the carbon dioxide loop heat regenerator 3 in sequence through pipelines and then is communicated with the inlet of the carbon dioxide compressor 1.

The cooling water outlet of the carbon dioxide loop water-cooling gas cooler 2 is connected with an air-water heater 11, a stop valve 14, a first three-way water valve 18, a first air radiator 19, a second water pump 21, a fourth three-way water valve 22 and a first water pump 23 in sequence through pipelines and then is communicated with the cooling water inlet of the carbon dioxide loop water-cooling gas cooler 2.

The electric automobile heat management system further comprises a battery heat dissipation module, the battery heat dissipation module comprises a third water pump 13, a third three-way water valve 12, a power battery heat pipe 15 and a second three-way water valve 17, and a cooling water outlet of the carbon dioxide loop water-cooled evaporator 5 is communicated with the second three-way water valve 17, the power battery heat pipe 15, the third three-way water valve 12 and the third water pump 13 in sequence through pipelines and then communicated with a cooling water inlet of the carbon dioxide loop water-cooled evaporator 5.

The charging unit and the inverter radiator 24 are sequentially connected with the motor and control radiator 25, the third water pump 13, the carbon dioxide loop water-cooling evaporator 5, the second three-way water valve 17 and the second air radiator 20 through pipelines and then are connected with the charging unit and the inverter radiator 24 to form a radiating loop.

The second working medium heat management module comprises a second working medium compressor 7, a second working medium water-cooled condenser 8, a second working medium thermal expansion valve 9 and a second working medium evaporator 10, wherein an outlet of the second working medium compressor 7 is communicated with an inlet of the second working medium compressor 7 after being sequentially connected with the second working medium water-cooled condenser 8, the second working medium thermal expansion valve 9 and the second working medium evaporator 10 through pipelines. The condensed water inlet of the second working medium water-cooled condenser 8 is communicated with a second water pump 21, and the condensed water outlet of the second working medium water-cooled condenser 8 is communicated with a first three-way water valve 18.

A fourth three-way water valve 22 is connected between the second water pump 21 and the first water pump 23, and a pipeline between the first three-way water valve 18 and the stop valve 14 is communicated with the fourth three-way water valve 22. A one-way water valve 16 is communicated between the power battery heat pipe 15 and the second three-way water valve 17, the other end of the one-way water valve 16 is connected with a pipeline between the fourth three-way water valve 22 and the stop valve 14, and in the one-way water valve 16, the cooling liquid can only flow in the direction far away from the power battery heat pipe 15.

The second working medium is a refrigerant with better refrigeration efficiency than carbon dioxide, and the second working medium in the embodiment is R134a or R1234 yf. The carbon dioxide compressor 1 and the second working medium compressor 7 are both mechanical compressors driven by belt pulleys, and one of the compressors or both the compressors are controlled to operate by a motor through a clutch respectively.

With reference to fig. 2, in the cabin cooling mode, only the second working medium compressor 7 is operated by clutch control. After flowing out from the second working medium compressor 7, the high-temperature and high-pressure gaseous refrigerant transfers heat to the cooling liquid loop through the second working medium water-cooled condenser 8, and is finally driven by the second water pump 21 and released into ambient air through the first air radiator 19. The refrigerant which releases heat in the second working medium water-cooled condenser 8 and becomes liquid is throttled and decompressed by the second working medium thermal expansion valve 9 and becomes a low-temperature and low-pressure gas-liquid mixed state, and then enters the second working medium evaporator 10 to exchange heat with air in the vehicle, so that the refrigeration of the cockpit is realized. The refrigerant from the second working medium evaporator 10 returns to the inlet of the second working medium compressor 7 to realize circulation. The cooling of the charging unit and inverter radiator 24 and the drive motor and its control module radiator 25 is achieved by the third water pump 13 driving the coolant through the cooling circuit to dissipate heat through the second air radiator 20.

Referring to fig. 3, in a mode requiring both cabin refrigeration and power battery cooling, the carbon dioxide compressor 1 and the second working fluid compressor 7 work simultaneously, wherein the second working fluid is circulated for cabin refrigeration, the same as the operation mode in fig. 2. The carbon dioxide refrigerant is circulated for battery cooling, and the specific implementation is as follows. The high-temperature and high-pressure carbon dioxide refrigerant flows out of the carbon dioxide compressor 1, and releases heat to the cooling liquid circuit in the carbon dioxide circuit water-cooled gas cooler 2. The carbon dioxide refrigerant flowing out of the carbon dioxide loop water-cooled gas cooler 2 is further cooled by the carbon dioxide loop heat regenerator 3, throttled and decompressed by the carbon dioxide loop electronic expansion valve 4, and then changed into a low-temperature low-pressure gas-liquid mixed state to enter the carbon dioxide loop water-cooled evaporator 5. After absorbing the heat of the battery cooling loop, the carbon dioxide refrigerant flowing out of the carbon dioxide loop water-cooling evaporator 5 returns to the inlet of the carbon dioxide compressor 1 through the carbon dioxide gas-liquid separator 6 and the carbon dioxide loop heat regenerator 3 in sequence, thereby completing the circulation of the carbon dioxide refrigerant. In this mode, the third water pump 13, the second water pump 21, and the first water pump 23 are all turned on. Wherein a third water pump 13 is used to drive the battery cooling circuit. The second water pump 21 and the first water pump 23 are used for driving the cooling circuit to bring the heat absorbed from the second working medium water-cooled condenser 8 and the carbon dioxide circuit water-cooled gas cooler 2 into the first air radiator 19 through the cooling liquid and release the heat into the ambient air, and the first three-way water valve 18 has a flow distribution function.

Referring to fig. 4, when the system is in the cabin heating mode, the system operates only the carbon dioxide compressor 1 through clutch control. The high-temperature and high-pressure carbon dioxide refrigerant flows out of the carbon dioxide compressor 1, and releases heat to the cooling liquid circuit in the carbon dioxide circuit water-cooled gas cooler 2. The carbon dioxide refrigerant flowing out of the carbon dioxide loop water-cooling gas cooler 2 is further cooled by the carbon dioxide loop heat regenerator 3, then is throttled and depressurized by the carbon dioxide loop electronic expansion valve 4 to become a low-temperature and low-pressure gas-liquid mixed state, enters the carbon dioxide loop water-cooling evaporator 5, absorbs the heat of the cooling liquid loop by the carbon dioxide loop water-cooling evaporator 5, and returns to the inlet of the carbon dioxide compressor 1 through the carbon dioxide gas-liquid separator 6 and the carbon dioxide loop heat regenerator 3 in sequence, so that the circulation of the carbon dioxide refrigerant is completed. In this mode, the heat absorbed from the carbon dioxide loop water-cooled gas cooler 2 is driven by the first water pump 23 to heat the cabin by the heat exchange of the coolant with the air in the vehicle through the air water heater 11. The heat of the cooling liquid loop absorbed by the carbon dioxide refrigerant circulating in the carbon dioxide loop water-cooled evaporator 5 is partly from the ambient environment, the heat is realized by the second air radiator 20, the heat is generated by the charger inverter and the electric control of the motor, and the heat is realized by driving the cooling liquid to pass through the cooling loop by the third water pump 13.

In low temperature environments, the thermal management system needs to heat the power cells to improve the efficiency of the cells. Referring to fig. 5, when both the cabin and the power battery need to be heated in a low temperature environment, the operation mode of the refrigerant circuit is the same as that of fig. 4, and only the carbon dioxide compressor 1 is operated. The coolant circuit differs from that of figure 4 in that the coolant from the air water heater 11 does not return directly to the first water pump 23 but first continues through the power cell heat pipe 15 to heat the battery. At which time the shut-off valve 14 is closed.

Referring to fig. 6, the heating and dehumidifying mode of the system is shown. At this time, the carbon dioxide compressor 1 and the second working medium compressor 7 work simultaneously. The operation mode of the refrigerant cycle is the same as that of fig. 3. The wet air outside the vehicle is cooled and dehumidified by the second working medium evaporator 10, then flows through the air water heater 11 to be heated, and finally enters the cockpit. The heat absorbed by the cooling liquid loop from the second working medium water-cooled condenser 8 is driven by the second water pump 21 to release the cooling liquid to the ambient air through the first air radiator 19. The heat absorbed from the carbon dioxide circuit water cooled gas cooler 2 is transferred to the cabin by the first water pump 23 driving the coolant through the air water heater 11.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.