US20020112492A1 - Air conditioners suitable for vehicles and methods for operating such air conditioners - Google Patents

Air conditioners suitable for vehicles and methods for operating such air conditioners Download PDF

Info

Publication number
US20020112492A1
US20020112492A1 US10/078,201 US7820102A US2002112492A1 US 20020112492 A1 US20020112492 A1 US 20020112492A1 US 7820102 A US7820102 A US 7820102A US 2002112492 A1 US2002112492 A1 US 2002112492A1
Authority
US
United States
Prior art keywords
cooling medium
compressor
evaporator
refrigerant
air conditioner
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/078,201
Other languages
English (en)
Inventor
Ken Suitou
Kazuya Kimura
Masahiro Kawaguchi
Kazuhiro Kuroki
Hiroyuki Gennami
Ryo Matsubara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Industries Corp
Original Assignee
Toyota Industries Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Industries Corp filed Critical Toyota Industries Corp
Assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI reassignment KABUSHIKI KAISHA TOYOTA JIDOSHOKKI ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GENNAMI, HIROYUKI, MATSUBARA, RYO, KIMURA, KAZUYA, KUROKI, KAZUHIRO, SUITOU, KEN, KAWAGUCHI, MASAHIRO
Publication of US20020112492A1 publication Critical patent/US20020112492A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/002—Lubrication
    • F25B31/004—Lubrication oil recirculating arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H1/3204—Cooling devices using compression
    • B60H1/3205—Control means therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H1/3204—Cooling devices using compression
    • B60H1/3205—Control means therefor
    • B60H1/3214—Control means therefor for improving the lubrication of a refrigerant compressor in a vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H1/3204—Cooling devices using compression
    • B60H1/3222—Cooling devices using compression characterised by the compressor driving arrangements, e.g. clutches, transmissions or multiple drives
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/33—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant
    • F25B41/335—Expansion valves with the valve member being actuated by the fluid pressure, e.g. by the pressure of the refrigerant via diaphragms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H2001/3236—Cooling devices information from a variable is obtained
    • B60H2001/3248—Cooling devices information from a variable is obtained related to pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H2001/3236—Cooling devices information from a variable is obtained
    • B60H2001/3255—Cooling devices information from a variable is obtained related to temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H2001/3269—Cooling devices output of a control signal
    • B60H2001/3285—Cooling devices output of a control signal related to an expansion unit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/32—Cooling devices
    • B60H2001/3286—Constructional features
    • B60H2001/3292—Compressor drive is electric only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B27/00—Machines, plants or systems, using particular sources of energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/025—Motor control arrangements

Definitions

  • the present invention relates to air conditioners for vehicles and methods for operating such air conditioners.
  • the present invention relates to air controlling techniques in such air conditioners that have an air control circuit and a compressor, preferably an electrically driven compressor, for circulating a cooling medium or refrigerant within the air control circuit.
  • lubrication oil is typically utilized in order to lubricate sliding parts within the compressor.
  • lubrication oil recovering devices are usually disposed within the compressor in order to recover the lubrication oil and prevent the lubrication oil from flowing out of the compressor housing into the air conditioning circuit (e.g., into the condenser and evaporator).
  • incorporation of such lubrication oil recovering devices increases the manufacturing costs and size of such compressors and thus, elimination of such lubrication oil recovering devices would be advantageous.
  • air conditioners include an air conditioning circuit in which a cooling medium circulates.
  • a compressor may be disposed within the air conditioning circuit and preferably serves to compress the cooling medium and discharge the cooling medium under higher pressure.
  • the compressed cooling medium can then be expanded, e.g., in an evaporator, in order to cool a flow of air that will be supplied to the vehicle interior.
  • the compressor may comprise an electrically driven motor that drives the compressor.
  • a refrigerant superheat feedback device may preferably vary the degree of superheat or the superheat condition of the cooling medium that is returned to the compressor.
  • a superheat monitoring device may be disposed downstream of an evaporator in order to monitor the superheat condition of the cooling medium that is being returned to the compressor for compression. Based upon the detected superheat condition of the cooling medium downstream of the evaporator, the flow of cooling medium into the evaporator can be appropriately adjusted, as will be discussed further below.
  • the term “superheat” or “degree of superheat” is intended to mean the difference (usually, measured in degrees of Celsius or Fahrenheit) between the actual temperature of the cooling medium (refrigerant), which actual temperature is measured at a certain pressure, and the saturation temperature of the cooling medium (refrigerant) at that same pressure.
  • the degree of superheat of the cooling medium (refrigerant) may be expressed as the difference between the vapor point of the cooling medium at a certain pressure (i.e., the temperature at which the cooling medium evaporates at a given pressure) and the actual temperature of the cooling medium exiting the evaporator.
  • the cooling medium (refrigerant) is at a higher temperature when exiting the condenser than the vapor saturation temperature for the pressure at which the cooling medium is exiting the condenser, the difference is called the degree of superheat or the superheat condition of the cooling medium (refrigerant).
  • the refrigerant superheat feedback device may effectively control the superheat condition of the cooling medium that is being supplied to the compressor.
  • the cooling medium is substantially in a gaseous state.
  • the cooling medium is substantially in a liquid state.
  • the cooling medium may be in a substantially dual-phase gas-liquid state.
  • the refrigerant superheat feedback device can adjust the superheat condition of the cooling medium, so that the cooling medium exiting the evaporator is in a dual-phase state.
  • the liquid phase of the cooling medium can effectively convey lubrication oil into the compressor and reliably lubricate sliding parts within the compressor.
  • the air conditioner will not require a costly lubrication oil recovering device.
  • the air conditioner may have a relatively simple construction as compared to known air conditioning systems.
  • the inventors have found that the lubrication oil that flows out from the compressor can still be used to lubricating part within the compressor without incorporating lubrication oil recovering devices, if the lubrication oil adequately circulates within the air conditioning circuit and returns to the compressor.
  • the cooling medium may serve as a carrier for the lubrication oil.
  • the ability of the cooling medium to serve as a carrier for the lubrication oil may be improved by controlling the degree of superheat of the cooling medium. For example, saturated cooling medium having a liquid phase of the cooling medium may effectively convey the lubrication oil even if the flow rate of the cooling medium is relatively small, which may occur in a low load operation for the air conditioning system.
  • the flow rate of the lubrication oil through the air conditioning system will be relatively high. In that case, an adequate amount of lubricating oil will be returned to the compressor, even if the cooling medium is substantially in a gaseous state (i.e., the cooling medium returning to the compressor contains little or no liquid cooling medium).
  • methods for operating air conditioners include adjusting the superheat condition of the cooling medium that is supplied to the compressor in response to the load that is applied to the air conditioner. Therefore, if the superheat condition of the cooling medium, which is supplied to the compressor, is adjusted in response to the load that is applied to the air conditioner, the cooling medium may be brought into a dual-phase state, which includes a liquid phase of the cooling medium, in order to more effectively convey the lubrication oil within the air conditioning system.
  • FIG. 1 is a schematic diagram of a representative air conditioner
  • FIG. 2 shows a representative cross-charge expansion valve and associated parts
  • FIG. 3 shows the relationship between valve lift and the flow rate of cooling medium (refrigerant) compared to the enthalpy of the cooling medium (refrigerant);
  • FIG. 4 is a graph showing the relationship between temperature T( 12 ) and pressure P( 12 ) at an outlet of an evaporator of the air conditioner when a representative expansion valve is incorporated;
  • FIG. 5 is a Mollier chart for a cooling medium circulation process of the air controlling circuit.
  • the refrigerant superheat feedback device may vary the state (e.g., dual-phase state or substantially gaseous state) of the cooling medium that returns to the compressor during the circulating process in response to the load applied to the air conditioner (e.g., the compressor) during the air conditioning operation.
  • the refrigerant superheat feedback device preferably performs two functions: (1) monitoring the superheat condition (e.g., the enthalpy) of the cooling medium that is exhausted from an evaporator and which cooling medium will be supplied to the compressor and (2) adjusting the flow of cooling medium into the evaporator in order to maintain an appropriate state of the cooling medium that is exhausted from the evaporator.
  • the cooling medium that is being exhausted from the evaporator may be maintained in a substantially gaseous state, thereby transferring the maximum amount of cooling energy to a flow of air that will be supplied to the vehicle interior.
  • the flow rate of the cooling medium within the air conditioning system is relatively high, sufficient lubricating oil will be circulated to the compressor in order to reliably lubricate the compressor parts, even though the cooling medium is substantially in a gaseous state.
  • the flow rate of the cooling medium within the air conditioning systems also may be relatively low. Because gaseous cooling medium is less effective for conveying lubricating oil than liquid cooling medium, the compressor may not be adequately lubricated if only gaseous cooling medium is being supplied to the compressor in a low load operation. Therefore, the superheat state of the cooling medium exiting the evaporator can be adjusted by changing the flow of cooling medium into the evaporator in order to ensure that dual-phase cooling medium is exhausted from the evaporator and is conveyed to the compressor during a low load operation.
  • the dual-phase cooling medium includes a liquid phase that can effectively convey the lubricating oil, adequate lubrication of the compressor can be ensured, even in low load operations. Consequently, it is not necessary to utilize a lubricating oil recovery device within the air conditioning system, because an adequate supply of lubricating oil to the compressor is ensured during all types of workload on the air conditioning system (i.e., the compressor).
  • the refrigerant superheat feedback device may include a control valve disposed within the air control circuit, or any other type of controller, that is coupled to the air conditioning circuit but is physically isolated from the cooling medium within the air conditioning circuit.
  • a control valve disposed within the air control circuit, or any other type of controller, that is coupled to the air conditioning circuit but is physically isolated from the cooling medium within the air conditioning circuit.
  • an expansion valve may be utilized to control the flow rate of the cooling medium in response to changes in the load applied to the air conditioning system.
  • the refrigerant superheat feedback device may be a separate control valve. Also, the combination of these valves may be used.
  • the refrigerant superheat feedback device may include a device that monitors the superheat condition of the cooling medium exiting the evaporator and adjusts the flow rate of cooling medium into the evaporator.
  • a cross-charge type expansion valve may be utilized for this purpose.
  • such a device includes two features.
  • a means for monitoring the temperature of the cooling medium is provided.
  • a substantially sealed volume of gas which gas preferably has a composition that differs from the cooling medium, may be disposed substantially adjacent to the portion of the air conditioning circuit containing the cooling medium that has been exhausted from the evaporator.
  • this gas is physically isolated from the cooling medium, but is disposed in a manner so as to have substantially the same temperature as the cooling medium, the gas will expand and contract as the temperature of the cooling medium respectively increases and decreases.
  • a means for monitoring the pressure of the cooling medium also is preferably provided.
  • a movable diaphragm may separate the cooling medium within the air conditioning system and the gas within means for monitoring the temperature of the cooling medium.
  • the diaphragm will change position. If the diaphragm is coupled to the expansion valve, the change in position of the diaphragm will change the opening degree of the expansion valve. Therefore, the superheat condition of the cooling medium that is being exhausted by the evaporator is reflected by the position of the diaphragm. Further, the position of the diaphragm determines the flow rate of the cooling medium into evaporator.
  • the superheat condition of the cooling medium that is exiting the evaporator can be effectively “fed back” to the expansion valve in order to control the opening degree of the expansion valve.
  • the flow rate of the cooling medium into the evaporator also can be effectively controlled in order to maintain the state of the cooling medium that is exiting the evaporator in a condition that will effectively convey sufficient lubricating oil to the compressor and ensure adequate lubrication of the compressor.
  • the refrigerant superheat feedback device may decrease the superheat condition (e.g., enthalpy) of the cooling medium that is supplied to the compressor.
  • the gaseous cooling medium may be brought into a dual-phase state that includes a liquid phase. Therefore, the lubrication oil may be conveyed by the liquid phase of the cooling medium so as to reliably circulate and return to the compressor. As a result, the lubrication of parts within the compressor may be reliably maintained, and the durability of the compressor may be improved.
  • the lubrication oil can be effectively circulated in a cost-effective and simple manner by incorporating such a refrigerant superheat feedback device and the air conditioner will not require a costly lubrication oil recovering device.
  • the refrigerant superheat feedback device which may include an expansion valve, may serve to cause the cooling medium that is being returned to the compressor to be substantially a vapor (i.e., substantially gaseous state) when the load applied to the air conditioner is high and the flow rate of circulating cooling medium is relatively large.
  • the expansion valve may serve to cause the cooling medium that is being returned to the compressor to be dual-phase (i.e., gas-liquid).
  • the lubrication oil can be effectively circulated in a cost-effective and simple manner by incorporating a refrigerant superheat feedback device having the above features and the air conditioner does not require a costly lubrication oil recovering device. Furthermore, the compressor can be effectively operated regardless of the workload on the air conditioning system.
  • methods for operating an air conditioner may include adjusting the superheat condition of the cooling medium in response to a load that is applied to the air conditioner. For example, if the load applied to the air conditioner is low and the flow rate of circulating cooling medium is relatively small, the superheat condition of the cooling medium, which is being returned to the compressor, may be controlled such that the cooling medium is brought to a dual-phase state.
  • the vapor of the cooling medium will partially liquefied.
  • the lubrication oil within the compressor flows into the air control circuit when the load applied to the air conditioner is low and the flow rate of circulating cooling medium is small, the lubrication oil may flow together with the liquefied phase of the vapor and then may return to the compressor. Consequently, the lubrication oil can be effective circulated in a cost-effective and simple manner.
  • the air conditioner 1 may include an air controlling circuit 2 that serves to circulate cooling medium or refrigerant.
  • An electrically driven compressor C, a condenser 10 , an evaporator 12 , a receiver 14 and an expansion valve 20 may be disposed within the air controlling circuit 2 .
  • the compressor C preferably serves to compress a gaseous, or substantially gaseous, cooling medium and discharge pressurized cooling medium.
  • An inverter I may be included to selectively power an electric motor M that drives the compressor C.
  • the compressor C may be a scroll-type compressor.
  • a vehicle engine E may serve as the drive source of a vehicle and may be mechanically connected to an alternator O, e.g., by a belt or another transmission means.
  • the alternator O may be electrically connected to a battery B and also to the inverter I. Therefore, electric current generated by the alternator O may be utilized to drive the motor M or may charge the battery B.
  • the expansion valve 20 preferably serves as a pressure reducer or regulator by rapidly expanding the relatively high temperature, high-pressure liquid refrigerant supplied by the condenser 10 .
  • the liquid refrigerant e.g., through a small opening (not shown) in the expansion valve 20 , a relatively low temperature, low-pressure gas-liquid two-phased atomized refrigerant may be generated.
  • thermosensitive cylinder or element 22 may be utilized to essentially “feedback” the superheat condition of the cooling medium at the exhaust port of the evaporator 12 to the evaporation valve 20 in order to control the supply of refrigerant to evaporator 12 .
  • the thermosensitive cylinder 22 preferably contains a gaseous composition that is different from the cooling medium or refrigerant that is disposed within the air conditioning circuit 2 .
  • the gas within the thermosensitive cylinder 22 is preferably isolated from the refrigerant within the air conditioning circuit 2 .
  • the thermosensitive cylinder 22 is disposed so as to adjoin or substantially contact the portion of the air conditioning circuit 2 containing the refrigerant that has been exhausted from the evaporator 12 .
  • thermosensitive cylinder 22 may serve as a refrigerant temperature detector that detects the temperature of the gaseous refrigerant that is being fed into the compressor C after having been exhausted from the evaporator 12 .
  • the gas within the thermosensitive cylinder 22 preferably assumes the same temperature as the cooling medium exiting the evaporator 12 , due to the proximal relationship of the thermosensitive cylinder 22 and the air conditioning circuit 2 .
  • the expansion valve 20 may be a cross-charge expansion valve and may include a throttle valve 21 that is disposed at the inlet of the expansion valve 20 .
  • a spring 23 may bias the throttle valve 21 .
  • the throttle valve 21 may connected to a diaphragm 25 that is disposed within a diaphragm chamber 27 .
  • a first side of the diaphragm chamber 27 may communicate with the thermosensitive cylinder 22 via a first tube 29 (i.e., the gas within the thermosensitive cylinder 22 applies pressure to the first side of the diaphragm 25 ).
  • a second side of the diaphragm chamber 27 may communicate with the outlet side of the evaporator 12 via a second tube 31 (i.e., the cooling medium within the air conditioning circuit 2 applies pressure to the second side of the diaphragm 25 ).
  • the position of the throttle valve 21 i.e., the degree of opening
  • the second tube 31 is disposed in a way that it circumvents the evaporator 12 and forms a pressure guiding passage which connects the interior of the thermosensitive cylinder 22 with the interior of a pressure chamber provided at one side of the diaphragm 25 .
  • the first tube 29 serves as pressure communication unit for communicating pressure changes within the thermosensitive cylinder 22 to the pressure chamber provided at the other side of the diaphragm 25 .
  • activated carbon CA may be contained within the thermosensitive cylinder 22 .
  • the gas disposed within the thermosensitive cylinder 22 is different in kind or composition from the refrigerant flowing through the air controlling circuit 2 .
  • this different gas is sealed within a channel that connects the diaphragm chamber 27 and the thermosensitive cylinder 22 , as discussed above.
  • the gas within this channel is chosen such that at least some of the gas is absorbed by the activated carbon CA in order to provide a reservoir of gas for expansion, when the temperature of the cooling medium that is being discharged from the evaporator 12 increases.
  • the thermosensitive cylinder 22 may be attached to the outlet of the evaporator 12 , so that the pressure within the thermosensitive cylinder 22 , as well as the pressure within the first tube 29 , varies in response to the superheat condition of the refrigerant at the outlet of the evaporator 12 .
  • the amount of absorption of the gas by the activated carbon may increase as the temperature at the outlet of the evaporator 12 decreases. Therefore, the pressure within the thermosensitive cylinder 22 may vary with changes in the temperature at the outlet of the evaporator 12 .
  • the opening degree of the throttle valve 21 of the expansion valve 20 may be controlled in response to the difference between the pressure of the gas within the thermosensitive cylinder 22 and the pressure of the refrigerant at the outlet of the evaporator 12 .
  • the degree of opening of the throttle valve 21 may be increased in order to increase the flow rate of the refrigerant into the evaporator. As a result, the refrigerant is prevented from reaching an excessive superheat condition.
  • FIG. 3 shows a schematic graph showing the relationship between the lift of the throttle valve 21 and the pressure difference ( ⁇ P) between the pressure within the first tube 29 (or the pressure within the upper side of the diaphragm chamber 22 ) and the pressure at the outlet of the evaporator 12 (or the pressure within the lower side of the diaphragm chamber 22 ).
  • P 0 is a predetermined value at which the valve 21 starts to open. Because cross-charge type expansion valves are well known in the art, further details concerning the construction of the expansion valve 20 are not necessary.
  • FIG. 4 An explanatory graph showing the characteristics of a cross charge type expansion valve is shown in FIG. 4.
  • FIG. 5 A Mollier chart for a cooling medium circulation process of the air controlling circuit is shown in FIG. 5.
  • the relationship between pressure P and enthalpy h for a phase change during the cooling medium circulation process generally may be represented by the Mollier chart shown in FIG. 5.
  • the change in enthalpy of the system is the latent heat of vaporization.
  • saturated refrigerant vapor A 1 ′ within the air conditioning circuit may be drawn into and adiabatically compressed by the compressor C and then may be discharged into the air conditioning circuit 2 as a superheated refrigerant vapor A 2 ′ that has a relatively high temperature and high pressure.
  • the superheated refrigerant vapor A 2 ′ discharged from the compressor C may be isobarically cooled (Q ( 10 )) and be liquefied within the condenser 10 and the receiver 14 so as to become a liquid cooling medium A 3 . That is, the vapor A 2 ′ is cooled without changing pressure.
  • the liquid cooling medium A 3 may then be expanded by the expansion valve 20 and the evaporator 12 in order to generate a gas-liquid refrigerant vapor A 4 .
  • the gas-liquid vapor A 4 may subsequently flow into the evaporator 12 and cool the air passing across the evaporator 12 (which cooled air will be supplied to the vehicle interior) through heat exchange between the gas-liquid vapor A 4 and the air.
  • the gas-liquid vapor A 4 absorbs energy from the air (Q ( 12 )), which causes the liquid content of the gas-liquid vapor A 4 to isobarically vaporize. As a result, the gas-liquid vapor A 4 may become a substantially saturated vapor A 1 ′, which is again suctioned into and pressurized by the compressor C.
  • the gas/liquid state of the cooling medium at the outlet of the evaporator 12 may vary in response to the degree of valve opening of the expansion valve 20 .
  • the compressor C may compress the saturated refrigerant vapor A 1 ′ into the superheated refrigerant vapor A 2 ′
  • the compressor also may compress superheated refrigerant vapor AI into superheated refrigerant vapor A 2 . That is, the degree of valve opening of expansion valve 20 will determine the enthalpy h of the refrigerant exhausted from the evaporator 12 , and thus the state of the refrigerant that is supplied to the compressor C.
  • the superheat condition SH 1 of the cooling medium may vary in response to the temperature T( 12 ) at the outlet of the evaporator 12 .
  • the superheat condition SH 2 of the cooling medium may be a fixed value irrespective of changes in the temperature T( 12 ).
  • the amount of energy Q( 12 ) to be exchanged between the cooling medium and the conditioning air becomes greater (i.e., the air controlling load is increased) during the circulation of cooling medium in the air controlling circuit 2 , the relative amount of vaporized cooling medium within the evaporator 12 may increase. Therefore, the temperature T( 12 ) at the outlet of the evaporator 12 may increase. According to the representative embodiment, the superheat condition SH 1 of the cooling medium may increase as the temperature T( 12 ) increases. As a result, the superheated cooling medium may return to the compressor C.
  • the amount of energy Q( 12 ) to be exchanged between the cooling medium and the conditioning air becomes less (i.e., the air controlling load is decreased) during the circulation of cooling medium
  • the amount of heat that may be absorbed by the conditioning air from the cooling medium flowing through the evaporator 12 may decrease. Therefore, the temperature T( 12 ) at the outlet of the evaporator 12 may decrease.
  • the superheat condition SH 1 of the cooling medium may decrease as the temperature T( 12 ) decreases.
  • the cooling medium at the outlet of the evaporator 12 may not be completely vaporized (i.e., the cooling medium will be in a dual gas-liquid state).
  • lubrication oil is disposed within the cooling medium in order to reliably lubricate sliding parts within the housing of the compressor C.
  • Known compressors generally utilize a lubrication oil recovering device for preventing the lubrication oil from leaking out into the air conditioning circuit along with the cooling medium that is discharged from the compressor housing.
  • the cooling medium that returns to the compressor is always in the state of a heated vapor.
  • the lubrication oil may not properly circulate with the relatively low flow of the gaseous cooling medium.
  • the compressor C may not be properly lubricated.
  • the electrically powered compressor C does not require a lubrication oil recovery device.
  • the cross-type expansion valve 20 may be incorporated to reliably circulate the lubrication oil during all workloads on the compressor C.
  • the cross-type expansion valve 20 ensures that the cooling medium is always at a proper condition (i.e., dual-phase or substantially gaseous) in order to reliably supply lubrication oil to the moving parts within the compressor C while also sufficiently cooling the air that will be supplied to the vehicle interior.
  • the expansion valve 20 may serve to vary the superheat condition of the cooling medium in response to the operation load applied to the air conditioner 1 .
  • the expansion valve 20 may serve to provide a partially liquefied refrigerant vapor (i.e., a dual phase gas-liquid) at the outlet of the expansion valve.
  • a dual phase refrigerant may be returned to the compressor C.
  • the lubrication oil may reliably return to the compressor C along with the flow of the liquefied cooling medium.
  • the circulation properties of the lubrication oil may be improved with respect to known air conditioners incorporating SH-type expansion valves, in particular during a low load operation of the air conditioner 1 .
  • the temperature of the cooling medium at the outlet of the expansion valve 20 may increase during the high load operation, this may not cause any problem, because the lubrication oil may flow along with the gaseous cooling medium that flows at a higher rate. Consequently, the circulation properties of the lubrication oil in the air conditioning circuit 2 may be improved.
  • the cross-charge expansion valve 20 may decrease the degree of superheat of the cooling medium that returns to the compressor C.
  • the cooling medium may be brought into a saturated state or a partly liquefied state, which state may improve the circulating properties of the cooling medium and the lubrication oil. Therefore, air conditioners having improved circulating properties can be easily attained at a lower cost by incorporating the representative expansion valve 20 in place of a known lubrication oil recovery device.
  • the present teachings should not be limited to the representative embodiment, but instead, may be used for different applications and may be modified in various ways.
  • the cross-charge type expansion valve 20 may be replaced with another device or devices that are capable of causing the superheat condition of the cooling medium that returns to the compressor C to appropriately change in order to supply adequate lubrication oil to the compressor.
  • expansion valves of different types or control valves can be advantageously utilized to vary the cross-sectional area of the flow line in the air conditioning circuit to control the refrigerant temperature.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid Mechanics (AREA)
  • Air-Conditioning For Vehicles (AREA)
  • Air Conditioning Control Device (AREA)
US10/078,201 2001-02-20 2002-02-19 Air conditioners suitable for vehicles and methods for operating such air conditioners Abandoned US20020112492A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001-043975 2001-02-20
JP2001043975A JP2002240545A (ja) 2001-02-20 2001-02-20 車両用空調装置およびその運転方法

Publications (1)

Publication Number Publication Date
US20020112492A1 true US20020112492A1 (en) 2002-08-22

Family

ID=18906049

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/078,201 Abandoned US20020112492A1 (en) 2001-02-20 2002-02-19 Air conditioners suitable for vehicles and methods for operating such air conditioners

Country Status (3)

Country Link
US (1) US20020112492A1 (de)
JP (1) JP2002240545A (de)
DE (1) DE10207113A1 (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6622505B2 (en) * 2001-06-08 2003-09-23 Thermo King Corporation Alternator/invertor refrigeration unit
US20040159111A1 (en) * 2002-04-08 2004-08-19 Masaaki Takegami Refrigerator
US20110110791A1 (en) * 2008-07-25 2011-05-12 Carrier Corporation Continuous compressor envelope protection
EP2436543A1 (de) * 2009-05-25 2012-04-04 Daikin Industries, Ltd. Kühlvorrichtung für einen anhänger
US20120117993A1 (en) * 2010-04-23 2012-05-17 Panasonic Corporation Vehicle air conditioning device
US20130248165A1 (en) * 2012-03-21 2013-09-26 Thermo King Corporation Power regulation system for a mobile environment-controlled unit and method of controlling the same
DE102013212009A1 (de) * 2013-06-25 2015-01-08 Bayerische Motoren Werke Aktiengesellschaft Kältekreislauf-Anlage zur Klimatisierung eines Fahrzeugs, insbesondere eines Elektro- oder Hybridfahrzeuges sowie Verfahren und Verdichter zum Betrieb einer solchen Kältekreislauf-Anlage
CN107631519A (zh) * 2017-08-18 2018-01-26 珠海格力电器股份有限公司 空调机组自动回油控制方法、装置、存储介质及空调机组
US10436488B2 (en) * 2002-12-09 2019-10-08 Hudson Technologies Inc. Method and apparatus for optimizing refrigeration systems

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011080736A (ja) * 2009-10-09 2011-04-21 Itsuwa Kogyo Kk 熱交換装置

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6622505B2 (en) * 2001-06-08 2003-09-23 Thermo King Corporation Alternator/invertor refrigeration unit
US20040159111A1 (en) * 2002-04-08 2004-08-19 Masaaki Takegami Refrigerator
US6986259B2 (en) * 2002-04-08 2006-01-17 Daikin Industries, Ltd. Refrigerator
US10436488B2 (en) * 2002-12-09 2019-10-08 Hudson Technologies Inc. Method and apparatus for optimizing refrigeration systems
US20110110791A1 (en) * 2008-07-25 2011-05-12 Carrier Corporation Continuous compressor envelope protection
EP2436543A4 (de) * 2009-05-25 2017-05-03 Daikin Industries, Ltd. Kühlvorrichtung für einen anhänger
EP2436543A1 (de) * 2009-05-25 2012-04-04 Daikin Industries, Ltd. Kühlvorrichtung für einen anhänger
US20120117993A1 (en) * 2010-04-23 2012-05-17 Panasonic Corporation Vehicle air conditioning device
US9211778B2 (en) * 2010-04-23 2015-12-15 Panasonic Intellectual Property Management Co., Ltd. Vehicle air conditioning device
US20130248165A1 (en) * 2012-03-21 2013-09-26 Thermo King Corporation Power regulation system for a mobile environment-controlled unit and method of controlling the same
US9562715B2 (en) * 2012-03-21 2017-02-07 Thermo King Corporation Power regulation system for a mobile environment-controlled unit and method of controlling the same
DE102013212009B4 (de) 2013-06-25 2019-05-23 Bayerische Motoren Werke Aktiengesellschaft Kältekreislauf-Anlage zur Klimatisierung eines Fahrzeugs, insbesondere eines Elektro- oder Hybridfahrzeuges sowie Verfahren und Verdichter zum Betrieb einer solchen Kältekreislauf-Anlage
DE102013212009A1 (de) * 2013-06-25 2015-01-08 Bayerische Motoren Werke Aktiengesellschaft Kältekreislauf-Anlage zur Klimatisierung eines Fahrzeugs, insbesondere eines Elektro- oder Hybridfahrzeuges sowie Verfahren und Verdichter zum Betrieb einer solchen Kältekreislauf-Anlage
CN107631519A (zh) * 2017-08-18 2018-01-26 珠海格力电器股份有限公司 空调机组自动回油控制方法、装置、存储介质及空调机组

Also Published As

Publication number Publication date
JP2002240545A (ja) 2002-08-28
DE10207113A1 (de) 2002-10-10

Similar Documents

Publication Publication Date Title
US5685160A (en) Method for operating an air conditioning cooling system for vehicles and a cooling system for carrying out the method
US6823691B2 (en) Vapor compression refrigerant cycle
US6341496B1 (en) Electrically driven compression-type refrigeration system with supercritical process
US6343486B1 (en) Supercritical vapor compression cycle
US9170038B2 (en) Air conditioning unit for vehicles and method of operating the same
US11180000B2 (en) Vehicle-mounted temperature controller
EP2326841B1 (de) Kompressorentladungssteuerung in einem transportkühlsystem
US20020050143A1 (en) Cooling cycle and control method thereof
JP3365273B2 (ja) 冷凍サイクル
EP2739494B1 (de) Kühlsystem
JP2002168532A (ja) 超臨界蒸気圧縮システム、および超臨界蒸気圧縮システム内部を循環する冷媒の高圧成分における圧力を調整する装置
KR20060022275A (ko) 증기 압축 시스템의 초임계 압력 조절
JP4115017B2 (ja) 冷凍空調装置
US20060242976A1 (en) Air conditioner and control system therefor
US20140223925A1 (en) Heat exchange apparatus and method for controlling heat exchange apparatus
US20020112492A1 (en) Air conditioners suitable for vehicles and methods for operating such air conditioners
US20080250812A1 (en) Multi-Circuit Refrigerant System Utilizing Pulse Width Modulation Techniques
CA1071420A (en) Automotive heat pump
JP2000205670A (ja) 蒸気圧縮式冷凍サイクル
US9139066B2 (en) Combined operation and control of suction modulation and pulse width modulation valves
JP4338539B2 (ja) 車両用空調装置
JP2004101143A (ja) 蒸気圧縮式冷凍機
AU2361899A (en) Controlling refrigerant in a closed loop recirculating system
KR20070033215A (ko) 공조장치용 초임계 냉매 시스템의 제어구조 및 방법
JP2008121913A (ja) 蒸気圧縮式冷凍サイクル

Legal Events

Date Code Title Description
AS Assignment

Owner name: KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SUITOU, KEN;KIMURA, KAZUYA;KAWAGUCHI, MASAHIRO;AND OTHERS;REEL/FRAME:012625/0982;SIGNING DATES FROM 20020205 TO 20020208

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION