Air conditioning system provided with an electronic expansion valve

Patent metadata

Field	Value
Publication number	US-9341398-B2
Application number	US-3884808-A
Country	US
Kind code	B2
Filing date	Feb 28, 2008
Priority date	Feb 28, 2007
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

An air conditioning device is used in a motor vehicle. The air conditioning device includes air conditioning circuit, which includes a compressor ( 14 ), a condenser ( 11 ), and/or an internal exchanger, an electric expansion valve ( 12 ) which opening ratio is changed according to a control signal, and an evaporator ( 13 ), which are traversed in this order by a refrigerant fluid and a control unit ( 40 ) capable of controlling a control signal of the expansion valve so as to regulate a control variable relating to the superheating of the evaporator or to the sub-cooling of the condenser ( 11 ) according to a chosen regulation rule.

First claim

The invention claimed is:

1. An air conditioning system for a motor vehicle, the air conditioning system comprising;
a compressor ( 14 ) including a control valve, for which a passage section varies as a function of a compressor control signal,
a condenser or a gas cooler ( 11 ),
an electronic expansion valve ( 12 ), for which a degree of opening varies as a function of a control signal with the degree of opening having a predetermined opening threshold,
an evaporator ( 13 ),
a refrigerant fluid for circulating though the compressor ( 14 ), the condenser or gas cooler ( 11 ), the electronic expansion valve ( 12 ), and the evaporator ( 13 ),
an internal exchanger ( 9 ) allowing the refrigerant fluid circulating from the condenser or gas cooler ( 11 ) towards the expansion valve ( 12 ) to exchange heat with the refrigerant fluid circulating from the evaporator ( 13 ) toward the compressor ( 14 ),
a pressure and temperature sensor ( 20 ) positioned at an outlet of the compressor ( 14 ) with the pressure and temperature sensor ( 20 ) configured to measure temperature and pressure of the refrigerant fluid at the outlet of the compressor,
a temperature probe ( 29 ) positioned at an inlet of expansion valve ( 12 ) and placed into contact with the refrigerant fluid upon entry of the refrigerant fluid into the expansion valve ( 12 ) with the temperature probe ( 29 ) configured to measure a sub-cooling temperature of the refrigerant fluid; and
a control unit ( 40 ) in communication with the compressor ( 14 ), the expansion valve ( 12 ), the temperature and pressure sensor ( 20 ), and the temperature probe ( 29 ),
wherein the control unit ( 40 ) generates the control signal for varying the degree of opening of the expansion valve and generates the compressor control signal for adjusting a capacity of the compressor ( 14 ) based on the temperature and the pressure measured by the pressure and temperature sensor ( 20 ) and on the sub-cooling temperature of the refrigerant fluid measured by the temperature probe ( 29 ) for regulating a control variable relating to superheating of the evaporator or to sub-cooling of the condenser ( 11 ) according to a chosen regulation rule and so as to regulate an efficiency of the internal exchanger ( 9 ), and
wherein the control signal for varying the degree of opening of the expansion valve is based on a comparison of the temperature and the pressure of the refrigerant fluid carried out by the pressure and temperature sensor ( 20 ) with threshold values and is based on a comparison of the sub-cooling temperature of the refrigerant fluid carrier out by the temperature sensor ( 29 ) with a reference value.

2. A system according to claim 1 , wherein the control unit ( 40 ) is capable of determining the reference value of a desired temperature of the refrigerant fluid at the inlet of the expansion valve ( 12 ) based on a relationship between a sub-cooling and an optimal coefficient of performance of the system.

3. A system according to claim 2 , wherein the control variable relating to the sub-cooling of the condenser ( 11 ) corresponds to the sub-cooling temperature of the refrigerant fluid.

4. A system according to claim 1 , wherein the compressor ( 14 ) is an externally controlled compressor and the control unit ( 40 ) is further capable of controlling the expansion valve and the compressor so as to maintain a temperature and an expulsion pressure at an outlet of the compressor ( 14 ) below respective predetermined thresholds.

5. A system according to claim 1 , wherein the control unit is capable of comparing an efficiency of the internal exchanger with a predefined threshold to regulate the efficiency of the internal exchanger ( 9 ).

6. A system according to claim 1 , wherein the control unit is capable of determining an efficiency value of the internal exchanger ( 9 ) from a mass output of the fluid estimated as a function of measurements of a high pressure and a sub-cooling temperature of the refrigerant fluid.

7. A system according to claim 1 , wherein the regulation of the control variable is a closed-loop regulation.

8. A system according to claim 1 , wherein the control unit generates the compressor control signal for the compressor to limit a temperature of discharge and/or suction of the compressor.

9. A system according to claim 1 , wherein the control unit ( 40 ) generates the compressor control signal for adjusting a capacity of the compressor ( 14 ) once the degree of opening of the expansion valve ( 12 ) required by the control signal is greater than the predetermined opening threshold of the expansion valve ( 12 ).

Assignees

• Liu Jin Ming
• Valeo Systemes Thermiques

Inventors

• Liu Jin Ming

Classifications

• F25B2700/21172

  at the inlet · CPC title

• F25B2700/21173

  at the outlet · CPC title

• F25B2600/17

  by controlling the pressure of the condenser · CPC title

• F25B2341/063

  Feed forward expansion valves · CPC title

• Y02B30/72

  Cross-Sectional Technologies · mapped topic