US20010003903A1 - Method for checking the state of a closed loop air-conditioning system comprising a variable-throughput compressor - Google Patents

Method for checking the state of a closed loop air-conditioning system comprising a variable-throughput compressor Download PDF

Info

Publication number
US20010003903A1
US20010003903A1 US09/736,399 US73639900A US2001003903A1 US 20010003903 A1 US20010003903 A1 US 20010003903A1 US 73639900 A US73639900 A US 73639900A US 2001003903 A1 US2001003903 A1 US 2001003903A1
Authority
US
United States
Prior art keywords
temperature
compressor
airflow
evaporator
throughput
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.)
Granted
Application number
US09/736,399
Other versions
US6378316B2 (en
Inventor
Jin Liu
Bruno Hamery
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.)
Valeo Climatisation SA
Original Assignee
Valeo Climatisation SA
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 Valeo Climatisation SA filed Critical Valeo Climatisation SA
Assigned to VALEO CLIMATISATION reassignment VALEO CLIMATISATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HAMERY, BRUNO, LIU, JIN MING
Publication of US20010003903A1 publication Critical patent/US20010003903A1/en
Application granted granted Critical
Publication of US6378316B2 publication Critical patent/US6378316B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/005—Arrangement or mounting of control or safety devices of safety devices
    • 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
    • B60H1/3211—Control means therefor for increasing the efficiency of a vehicle refrigeration cycle
    • 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
    • B60H1/3225—Cooling devices using compression characterised by safety arrangements, e.g. compressor anti-seizure means or by signalling devices
    • 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
    • F25B49/022—Compressor control 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
    • B60H2001/3236—Cooling devices information from a variable is obtained
    • B60H2001/3248—Cooling devices information from a variable is obtained related to pressure
    • B60H2001/325—Cooling devices information from a variable is obtained related to pressure of the refrigerant at a compressing 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
    • B60H2001/3236—Cooling devices information from a variable is obtained
    • B60H2001/3255—Cooling devices information from a variable is obtained related to temperature
    • B60H2001/3261—Cooling devices information from a variable is obtained related to temperature of the air at an evaporating 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
    • B60H2001/3236—Cooling devices information from a variable is obtained
    • B60H2001/3255—Cooling devices information from a variable is obtained related to temperature
    • B60H2001/3263—Cooling devices information from a variable is obtained related to temperature of the refrigerant at an evaporating 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
    • B60H2001/3269—Cooling devices output of a control signal
    • B60H2001/328—Cooling devices output of a control signal related to an evaporating unit
    • B60H2001/3283—Cooling devices output of a control signal related to an evaporating unit to control the refrigerant flow
    • 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

Definitions

  • the invention relates to the air conditioning of the passenger compartment of motor vehicles.
  • a closed loop air-conditioning system having a loop of refrigerant fluid and including a compressor, a condenser, a pressure-reduction valve and an evaporator, the latter being in contact with an airflow to be cooled.
  • the compressor was continuously driven by the engine of the vehicle so as to produce a throughput of refrigerant fluid determined by the speed of the engine.
  • the airflow greatly cooled by the evaporator, then passed through the radiator for heating the passenger compartment so as to be adjusted to the desired temperature.
  • variable-displacement compressors called internal-control compressors, the throughput of which could be set independently of their speed of rotation within the range of regulation of the displacement, by virtue of a valve the position of which was such that the entry pressure of the fluid was a function of the exit pressure.
  • variable-displacement compressors have a solenoid valve, preferably a chopper-type valve, the power-supply current of which determines the entry pressure of the fluid into the compressor.
  • the object of the invention is to make it possible to detect operating anomalies in a closed loop air-conditioning system comprising a variable-throughput compressor, and especially insufficient refrigerant-fluid level or a blockage of the control valve of the compressor.
  • the invention envisages, in particular, a method for checking the state of a closed loop system for air conditioning the passenger compartment of a motor vehicle, especially a system comprising an evaporator suitable for cooling an airflow to be sent into the passenger compartment, and a variable-throughput compressor controlled by an electrical control signal, in which method the temperature of the said airflow is determined by means of a sensor, a corresponding theoretical value of the said temperature is defined, for at least one value of the said control signal, the actual value of the temperature is compared with the theoretical value and the result of this comparison is used as an indicator of the normal or abnormal state of the loop.
  • the result of the comparison may especially indicate a low level of refrigerant fluid in the loop.
  • blockage of the valve of the compressor may also be revealed by the result of the comparison.
  • any low level of the refrigerant fluid is indicated by the fact that the actual temperature of the airflow exceeds a predetermined threshold with respect to the theoretical temperature.
  • the comparison is carried out after having applied a control current for sufficient time to produce a high throughput of the fluid.
  • any blockage of the valve of the compressor is indicated by the fact that the actual temperature of the airflow remains constant when the control current, and consequently the theoretical temperature, is varied.
  • the compressor is driven electrically.
  • the theoretical value or the threshold is defined by using parameters, in combination with the control signal, which link the temperature of the airflow to the pressure at the entry to the compressor.
  • the parameters comprise at least one of the following parameters: state of a blower producing the said airflow, position of a flap for recycling the air of the passenger compartment, speed of the vehicle, temperature of the air outside and inside the passenger compartment, relative humidity and temperature of the incident airflow and throughput of refrigerant fluid in the loop.
  • the sensor may be placed in the vicinity either of the superheated area, or of the coldest point of the evaporator, or else at a point of the evaporator taken to an intermediate temperature.
  • FIG. 1 is a diagrammatic side view of an evaporator of a vehicle air-conditioning system, equipped with an air-temperature probe with a view to implementing the method according to the invention.
  • FIG. 2 is a diagrammatic rear view of the evaporator.
  • FIG. 3 is a graph showing the variation in the temperature of the airflow as a function of the power-supply current of the control valve of the compressor.
  • the evaporator illustrated, designated by the reference 1 exhibits a front face, or entry face, 2 and a rear face, or exit face, 3 , and is traversed, from the front face 2 to the rear face 3 , by an airflow to be cooled represented by the arrow F.
  • a temperature probe 4 is embedded in the evaporator or downstream thereof, in the vicinity of its rear face 3 , so as to measure the temperature of the air cooled by the evaporator.
  • FIG. 2 shows the evaporator seen on its rear face.
  • a rectangle has been used to represent, diagrammatically, a region 5 of the evaporator, close to the outlet pipework, not represented, for the refrigerant fluid, in which the latter is superheated, after vaporization, when the air-conditioning system is operating normally.
  • the probe 4 is situated outside this region and at a short distance from it. It is therefore been swept by the air that has traversed the remaining area of the evaporator, where the refrigerant fluid is in liquid/gas equilibrium. This air is at a temperature theoretically related to the pressure of the fluid at the entry to the compressor and consequently to the power-supply current of the control valve thereof, as set out above.
  • the superheated fluid occupies a region 6 of the evaporator larger than the region 5 and encompassing the probe 4 .
  • the temperature measured by the probe is therefore higher than the theoretical temperature defined by the control current of the compressor.
  • FIG. 3 shows a typical curve representative of the variation in the theoretical temperature T 0 of the airflow having passed through the evaporator, as a function of the power-supply current I of the control valve of the compressor, which can vary between 0 and a maximum value Imax.
  • FIG. 3 also shows a curve B that associates with each value of I a temperature value T 1 higher than the corresponding value of the theoretical temperature To.
  • T 1 can be used as a threshold for detecting an insufficient fill level of refrigerant fluid in the air-conditioning loop.
  • the pressure of the fluid at the entry to the compressor which is determined directly by the current I, within the limits of the displacement of the compressor.
  • the temperature of the airflow having passed through the evaporator it is a function of the evaporation temperature in the evaporator and of various parameters such as the throughput of the airflow, its relative humidity and its temperature upstream of the evaporator, and the effectiveness of the evaporator.
  • the throughput of the airflow may depend, in its turn, on the state of a fan that produces it, on the position of a flap for recycling the air from the passenger compartment and on the speed of the vehicle.
  • the relationship between the evaporation temperature in the evaporator and the pressure of the refrigerant fluid at the entry to the compressor depends on the throughput of refrigerant fluid in the system. All these parameters, which are chosen in the context of the running of the air-conditioning installation, or which can be determined directly or indirectly by existing means, can be taken into account for calculating the theoretical temperature T 0 , the curve A of FIG. 3 depending on the instantaneous value of these parameters. In a variant, a fixed curve A can be used, and the curve B can be chosen in such a way that the temperature T 1 is always significantly higher than the theoretical temperature, corrected by the application of the parameters, whatever the values thereof.
  • the checking of the level of refrigerant fluid is performed with the vehicle in operation and/or during maintenance operations, by carrying out the comparison of temperatures after a defined period, for example, between 2 and 3 minutes, of operation of the compressor at a relatively high displacement.
  • a temperature probe for the cooled air in the vicinity of the coldest point of the evaporator, which is generally close to the entry pipework for the refrigerant fluid.
  • Such a probe is used for regulating the temperature of the airflow and/or for detecting a risk of the evaporator icing up.
  • the known probe can be used to implement the present invention, the detection of the low level then being later since an abnormally high temperature is measured only when the evaporator contains practically no fluid in the liquid state.
  • the probe used in the invention may also be arranged at any intermediate position.

Abstract

The temperature of an airflow cooled by an evaporator of a closed loop air-conditioning system, determined by means of a sensor, is compared with a theoretical value corresponding to the control current of an external-control, variable-displacement compressor, in order to detect a low level of refrigerant fluid in the system or any blocking of a compressor valve.

Description

    FIELD OF THE INVENTION
  • The invention relates to the air conditioning of the passenger compartment of motor vehicles. [0001]
    • BACKGROUND OF THE INVENTION
  • For this function, recourse is usually made to a closed loop air-conditioning system having a loop of refrigerant fluid and including a compressor, a condenser, a pressure-reduction valve and an evaporator, the latter being in contact with an airflow to be cooled. [0002]
  • In early systems, the compressor was continuously driven by the engine of the vehicle so as to produce a throughput of refrigerant fluid determined by the speed of the engine. The airflow, greatly cooled by the evaporator, then passed through the radiator for heating the passenger compartment so as to be adjusted to the desired temperature. [0003]
  • The cooling of the air, followed by reheating, was hardly satisfactory in terms of energy economy. To remedy that, recourse was made to variable-displacement compressors, called internal-control compressors, the throughput of which could be set independently of their speed of rotation within the range of regulation of the displacement, by virtue of a valve the position of which was such that the entry pressure of the fluid was a function of the exit pressure. As the settings obtained were still not sufficiently fine, externally controlled, variable-displacement compressors were developed. These compressors have a solenoid valve, preferably a chopper-type valve, the power-supply current of which determines the entry pressure of the fluid into the compressor. With this pressure being equal, to within a loss of pressure head, to that prevailing in the evaporator, which determines the operating temperature of the evaporator, it is thus possible to set the effectiveness of the air-conditioning loop with precision. An example of an external-control, variable-displacement compressor is described in EP-A-0 353 764. [0004]
  • In the event of leakage in the loop, the quantity of refrigerant fluid contained within the system will diminish. Below a refrigerant-fluid level threshold, the compressor risks being damaged in operation. [0005]
  • Moreover, it can happen that the control valve of the compressor becomes blocked and no longer allows the cooling power produced to be adjusted, whatever the power-supply current which is applied to it. [0006]
  • The object of the invention is to make it possible to detect operating anomalies in a closed loop air-conditioning system comprising a variable-throughput compressor, and especially insufficient refrigerant-fluid level or a blockage of the control valve of the compressor. [0007]
    • SUMMARY OF THE INVENTION
  • The invention envisages, in particular, a method for checking the state of a closed loop system for air conditioning the passenger compartment of a motor vehicle, especially a system comprising an evaporator suitable for cooling an airflow to be sent into the passenger compartment, and a variable-throughput compressor controlled by an electrical control signal, in which method the temperature of the said airflow is determined by means of a sensor, a corresponding theoretical value of the said temperature is defined, for at least one value of the said control signal, the actual value of the temperature is compared with the theoretical value and the result of this comparison is used as an indicator of the normal or abnormal state of the loop. [0008]
  • The result of the comparison may especially indicate a low level of refrigerant fluid in the loop. [0009]
  • This is because, in normal operation, the major part of the volume of the evaporator is full of refrigerant fluid in liquid/gas equilibrium, the temperature of which is determined by the pressure at the entry to the compressor, as indicated above. If the quantity of refrigerant fluid in the closed loop system is insufficient, then the evaporator contains only a small quantity of fluid in the liquid state, or even none at all, and on the contrary is filled entirely, or almost entirely, with fluid in the superheated gaseous state, that is to say at a temperature higher than the liquid/gas equilibrium temperature. A temperature sensor in contact with the evaporator for detecting the temperature of the airflow, or in contact with the air immediately downstream thereof, placed facing an area of the evaporator where the fluid is normally in liquid/gas equilibrium, will then be facing a superheated area and will detect a temperature higher than the theoretical temperature. [0010]
  • In the case of an external-control variable-displacement compressor as set out above, blockage of the valve of the compressor may also be revealed by the result of the comparison. [0011]
  • The choice of the power-supply current for the valve then no longer has any effect on the pressure at the entry to the compressor and consequently on the temperature of the airflow, the latter being just as likely to be above as below the theoretical value. [0012]
  • Optional characteristics of the invention, which are complementary or alternative, are set out below: [0013]
  • any low level of the refrigerant fluid is indicated by the fact that the actual temperature of the airflow exceeds a predetermined threshold with respect to the theoretical temperature. [0014]
  • in order to check the level of refrigerant fluid, the comparison is carried out after having applied a control current for sufficient time to produce a high throughput of the fluid. [0015]
  • any blockage of the valve of the compressor is indicated by the fact that the actual temperature of the airflow remains constant when the control current, and consequently the theoretical temperature, is varied. [0016]
  • the compressor is driven electrically. [0017]
  • the theoretical value or the threshold is defined by using parameters, in combination with the control signal, which link the temperature of the airflow to the pressure at the entry to the compressor. [0018]
  • the parameters comprise at least one of the following parameters: state of a blower producing the said airflow, position of a flap for recycling the air of the passenger compartment, speed of the vehicle, temperature of the air outside and inside the passenger compartment, relative humidity and temperature of the incident airflow and throughput of refrigerant fluid in the loop. [0019]
  • The sensor may be placed in the vicinity either of the superheated area, or of the coldest point of the evaporator, or else at a point of the evaporator taken to an intermediate temperature. [0020]
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The characteristics and advantages of the invention will be set out in more detail in the description below, by referring to the attached drawings. [0021]
  • FIG. 1 is a diagrammatic side view of an evaporator of a vehicle air-conditioning system, equipped with an air-temperature probe with a view to implementing the method according to the invention. [0022]
  • FIG. 2 is a diagrammatic rear view of the evaporator. [0023]
  • FIG. 3 is a graph showing the variation in the temperature of the airflow as a function of the power-supply current of the control valve of the compressor. [0024]
    • DETAILED DESCRIPTION OF THE INVENTION
  • The evaporator illustrated, designated by the reference [0025] 1, exhibits a front face, or entry face, 2 and a rear face, or exit face, 3, and is traversed, from the front face 2 to the rear face 3, by an airflow to be cooled represented by the arrow F. A temperature probe 4 is embedded in the evaporator or downstream thereof, in the vicinity of its rear face 3, so as to measure the temperature of the air cooled by the evaporator.
  • FIG. 2 shows the evaporator seen on its rear face. A rectangle has been used to represent, diagrammatically, a [0026] region 5 of the evaporator, close to the outlet pipework, not represented, for the refrigerant fluid, in which the latter is superheated, after vaporization, when the air-conditioning system is operating normally. The probe 4 is situated outside this region and at a short distance from it. It is therefore been swept by the air that has traversed the remaining area of the evaporator, where the refrigerant fluid is in liquid/gas equilibrium. This air is at a temperature theoretically related to the pressure of the fluid at the entry to the compressor and consequently to the power-supply current of the control valve thereof, as set out above.
  • In the event of a deficiency of refrigerant fluid, the superheated fluid occupies a [0027] region 6 of the evaporator larger than the region 5 and encompassing the probe 4. The temperature measured by the probe is therefore higher than the theoretical temperature defined by the control current of the compressor.
  • FIG. 3, at A, shows a typical curve representative of the variation in the theoretical temperature T[0028] 0 of the airflow having passed through the evaporator, as a function of the power-supply current I of the control valve of the compressor, which can vary between 0 and a maximum value Imax. FIG. 3 also shows a curve B that associates with each value of I a temperature value T1 higher than the corresponding value of the theoretical temperature To. Such a value T1 can be used as a threshold for detecting an insufficient fill level of refrigerant fluid in the air-conditioning loop.
  • In reality, it is the pressure of the fluid at the entry to the compressor which is determined directly by the current I, within the limits of the displacement of the compressor. As for the temperature of the airflow having passed through the evaporator, it is a function of the evaporation temperature in the evaporator and of various parameters such as the throughput of the airflow, its relative humidity and its temperature upstream of the evaporator, and the effectiveness of the evaporator. The throughput of the airflow may depend, in its turn, on the state of a fan that produces it, on the position of a flap for recycling the air from the passenger compartment and on the speed of the vehicle. Finally, as indicated above, the relationship between the evaporation temperature in the evaporator and the pressure of the refrigerant fluid at the entry to the compressor depends on the throughput of refrigerant fluid in the system. All these parameters, which are chosen in the context of the running of the air-conditioning installation, or which can be determined directly or indirectly by existing means, can be taken into account for calculating the theoretical temperature T[0029] 0, the curve A of FIG. 3 depending on the instantaneous value of these parameters. In a variant, a fixed curve A can be used, and the curve B can be chosen in such a way that the temperature T1 is always significantly higher than the theoretical temperature, corrected by the application of the parameters, whatever the values thereof.
  • The checking of the level of refrigerant fluid is performed with the vehicle in operation and/or during maintenance operations, by carrying out the comparison of temperatures after a defined period, for example, between 2 and 3 minutes, of operation of the compressor at a relatively high displacement. [0030]
  • It will be noted that it is known how to arrange a temperature probe for the cooled air in the vicinity of the coldest point of the evaporator, which is generally close to the entry pipework for the refrigerant fluid. Such a probe is used for regulating the temperature of the airflow and/or for detecting a risk of the evaporator icing up. By adapting the level for detecting the icing of the probe [0031] 4 described above, it is then possible to use it for detecting the icing. Likewise, it can be used for regulating the temperature of the airflow. The known probe can be used to implement the present invention, the detection of the low level then being later since an abnormally high temperature is measured only when the evaporator contains practically no fluid in the liquid state. The probe used in the invention may also be arranged at any intermediate position.

Claims (13)

1. A method for checking the state of a closed loop air conditioning system for air conditioning the passenger compartment of a motor vehicle, the system including an evaporator suitable for cooling an airflow to be sent into the passenger compartment, and a variable-throughput compressor controlled by an electrical control signal, in which method the temperature of the said airflow is determined by means of a sensor, a corresponding theoretical value of said temperature is defined, for at least one value of the said control signal, the actual value of the temperature is compared with the theoretical value and the result of this comparison is used as an indicator of the normal or abnormal state of the system.
2. A method according to
claim 1
, wherein the result of said comparison is used as an indicator of a low level of refrigerant fluid in the system.
3. A method according to
claim 2
, wherein a low level of the refrigerant fluid is indicated by the fact that the actual temperature of the airflow exceeds a predetermined threshold with respect to the theoretical temperature.
4. A method according to
claim 2
, wherein to check the level of refrigerant fluid, said comparison is carried out after having applied a control current for a sufficient time to produce a high throughput of said fluid.
5. A method according to
claim 1
, wherein the compressor is of the external-control, variable-displacement type, the said control signal being a control current supplying a valve incorporated in the compressor, the compressor being able to establish a pressure, at the entry thereto, which is determined by the said control current.
6. A method according to
claim 5
, wherein the result of said comparison is used as an indicator of any blockage of the valve of the compressor.
7. A method according to
claim 6
, wherein any blockage of the valve of the compressor is indicated by the fact that the actual temperature of the airflow remains constant when the said control current, and consequently the theoretical temperature, is varied.
8. A method according to
claim 1
, wherein the compressor is driven electrically.
9. A method according to
claim 1
, wherein said theoretical value or said threshold is defined by using parameters, in combination with said control signal, which link the temperature of the airflow to said pressure at the entry to the compressor.
10. A method according to
claim 9
, wherein the said parameters comprise at least one of the following parameters: state of a blower producing the said airflow, position of a flap for recycling the air of the passenger compartment, speed of the vehicle, temperature of the air outside and inside the passenger compartment, relative humidity and temperature of the incident airflow, throughput of refrigerant fluid in the loop.
11. A method according to
claim 1
, wherein said sensor is placed in the vicinity of a superheating area of the evaporator.
12. A method according to
claim 1
, wherein said sensor is placed in the vicinity of the coldest point of the evaporator.
13. A method according to
claim 1
, wherein said sensor is placed in the vicinity of a point of the evaporator at an intermediate temperature.
US09/736,399 1999-12-17 2000-12-15 Method for checking the state of a closed loop air-conditioning system comprising a variable-throughput compressor Expired - Lifetime US6378316B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9916008A FR2802472B1 (en) 1999-12-17 1999-12-17 METHOD FOR MONITORING THE CONDITION OF A MOTOR VEHICLE AIR CONDITIONING LOOP COMPRISING A VARIABLE FLOW COMPRESSOR
FR9916008 1999-12-17

Publications (2)

Publication Number Publication Date
US20010003903A1 true US20010003903A1 (en) 2001-06-21
US6378316B2 US6378316B2 (en) 2002-04-30

Family

ID=9553434

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/736,399 Expired - Lifetime US6378316B2 (en) 1999-12-17 2000-12-15 Method for checking the state of a closed loop air-conditioning system comprising a variable-throughput compressor

Country Status (5)

Country Link
US (1) US6378316B2 (en)
EP (1) EP1108577B1 (en)
DE (1) DE60034534T2 (en)
ES (1) ES2285990T3 (en)
FR (1) FR2802472B1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040018096A1 (en) * 2002-07-25 2004-01-29 Alexander Lifson Compressor degradation detection vapor compression system
US20050262855A1 (en) * 2004-05-25 2005-12-01 Ford Motor Company Method and system for assessing a refrigerant charge level in a vehicle air conditioning system
GB2564845A (en) * 2017-07-17 2019-01-30 Jaguar Land Rover Ltd A method for removing contamination from within a valve

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6463747B1 (en) * 2001-09-25 2002-10-15 Lennox Manufacturing Inc. Method of determining acceptability of a selected condition in a space temperature conditioning system
CN112060860B (en) * 2020-09-28 2021-11-19 恒大恒驰新能源汽车研究院(上海)有限公司 Temperature control method and device for vehicle air conditioning system and computer readable storage medium

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4102150A (en) * 1976-11-01 1978-07-25 Borg-Warner Corporation Control system for refrigeration apparatus
US4667480A (en) * 1986-09-22 1987-05-26 General Electric Company Method and apparatus for controlling an electrically driven automotive air conditioner
DE3706152A1 (en) * 1987-02-26 1988-09-08 Sueddeutsche Kuehler Behr METHOD FOR CONTROLLING A VEHICLE AIR CONDITIONER AND VEHICLE AIR CONDITIONER FOR IMPLEMENTING THE METHOD
US4790143A (en) * 1987-10-23 1988-12-13 Thermo King Corporation Method and apparatus for monitoring a transport refrigeration system and its conditioned load
JPH0667686B2 (en) * 1987-10-26 1994-08-31 株式会社ゼクセル Vehicle air conditioning controller
JP2661166B2 (en) 1988-08-05 1997-10-08 日産自動車株式会社 Vehicle air conditioner
US5251453A (en) * 1992-09-18 1993-10-12 General Motors Corporation Low refrigerant charge detection especially for automotive air conditioning systems
US5301514A (en) * 1992-12-02 1994-04-12 General Electric Company Low refrigerant charge detection by monitoring thermal expansion valve oscillation
JPH09178306A (en) * 1995-12-22 1997-07-11 Denso Corp Refrigerating cycle unit
JPH10122711A (en) * 1996-10-18 1998-05-15 Matsushita Electric Ind Co Ltd Refrigerating cycle control device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040018096A1 (en) * 2002-07-25 2004-01-29 Alexander Lifson Compressor degradation detection vapor compression system
US6799951B2 (en) * 2002-07-25 2004-10-05 Carrier Corporation Compressor degradation detection system
US20050262855A1 (en) * 2004-05-25 2005-12-01 Ford Motor Company Method and system for assessing a refrigerant charge level in a vehicle air conditioning system
US7337619B2 (en) 2004-05-25 2008-03-04 Ford Motor Company Method and system for assessing a refrigerant charge level in a vehicle air conditioning system
GB2564845A (en) * 2017-07-17 2019-01-30 Jaguar Land Rover Ltd A method for removing contamination from within a valve
GB2564845B (en) * 2017-07-17 2020-07-15 Jaguar Land Rover Ltd A method for removing contamination from within a valve

Also Published As

Publication number Publication date
EP1108577A1 (en) 2001-06-20
FR2802472A1 (en) 2001-06-22
DE60034534D1 (en) 2007-06-06
ES2285990T3 (en) 2007-12-01
DE60034534T2 (en) 2008-01-03
US6378316B2 (en) 2002-04-30
EP1108577B1 (en) 2007-04-25
FR2802472B1 (en) 2002-08-09

Similar Documents

Publication Publication Date Title
EP0677000B1 (en) Climate control system for electric vehicle
US5072597A (en) Control systems for automotive air conditioning systems
US7121103B2 (en) Vehicle air conditioning system
CN105987550B (en) Refrigeration system condenser fan control
US4646535A (en) Temperature and pressure monitored refrigeration system
US7275378B2 (en) Speed and system pressure control for cooling fan
EP2588819B1 (en) Evaporator refrigerant saturation demand defrost
KR101151095B1 (en) The Control Method of Electronic Control Valve for Variable Capacity Compressor of Air Conditioner
US5560217A (en) Air conditioning system of heat pump type
US20070151287A1 (en) Pressure-reducing module for dual evaporator air conditioning system
EP1293367B1 (en) Vehicle air conditioner having refrigerant cycle with heating function
US20040206098A1 (en) Air conditioner
US7841197B2 (en) Torque calculation apparatus and torque calculation method of variable capacitance compressor
JPH10147137A (en) Interior air conditioner for automobile
US7165411B2 (en) Control logic for HVAC heat management
EP0681933B1 (en) Air conditioning system of heat pump type
US6378316B2 (en) Method for checking the state of a closed loop air-conditioning system comprising a variable-throughput compressor
US6725676B2 (en) Refrigerant cycle system with hot gas heating function
US20020095942A1 (en) Ambient humidity compensation method for a vehicle climate control system
US6691523B1 (en) Air conditioning capacity control method for reducing motor vehicle engine exhaust emissions
US6260363B1 (en) Control strategy for operating an on-board vehicle refrigeration system
CN110843760A (en) Vehicle compressor control system and method thereof
US20070220908A1 (en) Vehicular air conditioner
US6508067B2 (en) Method for checking the refrigerant-fluid level of a closed loop vehicle air-conditioning system
EP0556641B1 (en) Method of controlling refrigerant flow in a refrigeration system

Legal Events

Date Code Title Description
AS Assignment

Owner name: VALEO CLIMATISATION, FRANCE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LIU, JIN MING;HAMERY, BRUNO;REEL/FRAME:011371/0251

Effective date: 20001211

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12