Vehicle air conditioning system

• US 6,553,775 B2
• Filed: 06/07/2001
• Issued: 04/29/2003
• Est. Priority Date: 06/07/2000
• Status: Active Grant

• Current Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Inventors: Asada, Hiroyuki, Togaru, Kazuhiro
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US09/875,102
• Publication Number:
  US 20020184899A1
• Time in Patent Office: 691 Days
• Field of Search: 621/33, 623/231, 622/30, 622/43, 622/44, 622/03, 622/281, 622/283, 622/284, 622/285, 623/234, 123/339.17, 123/339.23
• US Class Current: 62/133
• CPC Class Codes: B60H 1/3208 Vehicle drive related control of the compressor drive means, e.g. for fuel saving purposes
• CPC Class Codes: B60H 1/3216 for improving a change in operation duty of a compressor in a vehicle
• CPC Class Codes: B60H 2001/3248 related to pressure
• CPC Class Codes: B60H 2001/3255 related to temperature
• CPC Class Codes: B60H 2001/3266 related to the operation of the vehicle
• CPC Class Codes: B60H 2001/3273 related to the operation of the vehicle, e.g. the compressor driving torque

Abstract

A vehicle air conditioning system controls an engine and an air conditioner according to an air-conditioner load to thereby improve fuel economy and drivability of the vehicle. A higher compressor torque between a first estimated compressor torque, which is estimated according to the outside air temperature and the vehicle speed, and a second estimated compressor torque, which is estimated according to the refrigerant pressure, is adopted as an estimated compressor torque. When an air conditioner control switch is ON, an operational status of an engine and a compressor are controlled according to the adopted estimated compressor torque.

Claims

1. A vehicle air conditioning system, comprising:

a compressor driven by an engine, said compressor circulating a refrigerant for an air conditioner;

an outside air temperature sensing device that senses an outside air temperature;

a vehicle speed sensing device that senses a vehicle running speed;

a compressor torque estimating device that estimates a compressor torque required by said compressor of said air conditioner, said compressor torque estimating device estimating a first compressor torque according to the sensed outside air temperature and the sensed vehicle running speed; and

a control device for controlling an operational status of said engine according to said first compressor torque.

2. A vehicle air conditioning system according to claim 1, further comprising:

a high-pressure refrigerant pressure sensing device for sensing a high pressure refrigerant pressure in a refrigerant circuit provided in said air conditioner,

wherein said compressor torque estimating device estimates a second compressor torque according to the high pressure refrigerant pressure sensed by said high-pressure refrigerant pressure sensing device, and

said control device controls the operational status of said engine according to said first compressor torque or said second compressor torque.

3. A vehicle air conditioning system according to claim 2, wherein

said control device controls the operational status of said engine according to a higher compressor torque between said first compressor torque or said second compressor torque.

4. A vehicle air conditioning system according to claim 1, wherein

said control device controls said compressor after controlling the operational status of said engine.

5. A vehicle air conditioning system according to claim 2, further comprising:

an air conditioner control switch for turning on and off said air conditioner,

wherein said control device controls the operational status of said engine according to said first compressor torque until a predetermined period of time elapses after said air conditioner control switch is turned on.

6. A vehicle air conditioning system according to claim 2, wherein

said control device controls the operational status of said engine according to said first compressor torque when the high-pressure refrigerant pressure detected by said high-pressure refrigerant pressure sensing device is lower than a predetermined value.

7. A vehicle air conditioning system according to claim 1, further comprising:

an air conditioner control switch for turning on and off said air conditioner,

wherein said compressor torque estimating device estimates the first compressor torque before the compressor is turned on but after said air conditioner control switch is turned on.

8. A vehicle air conditioning system according to claim 1, further comprising:

an air conditioner control switch for turning on and off the air conditioner,

wherein said control device controls the operational status of the engine before the compressor is turned on but after said air conditioner control switch is turned on.

12. The method of controlling an engine according to claim 7, further comprising:

estimating a second compressor torque required by said compressor according to the sensed high-pressure refrigerant pressure;

selecting a higher compressor torque between said first compressor torque and said second compressor torque,

wherein said controlling step includes the step of,

controlling the operational status of said engine according to the selected one of said first compressor torque and said second compressor torque.

9. A vehicle air conditioning system, comprising:

a compressor for circulating air-conditioning refrigerant, said compressor being driven by an engine;

a compressor torque estimating device for estimating a compressor torque required by said compressor according to variations in an external load; and

a control device for controlling an operational status of said engine according to the compressor torque estimated by said compressor torque estimating device.

10. A method for controlling an engine in a vehicle air conditioning system having a compressor for circulating an air-conditioning refrigerant, the compressor being driven by an engine, a high-pressure refrigerant pressure sensing device for sensing a high-pressure refrigerant pressure, an outside air temperature sensing device for sensing an outside air temperature, and a vehicle speed sensing device for sensing a vehicle running speed, the method comprising:

estimating a first compressor torque according to the sensed outside air temperature and the sensed vehicle running speed; and

controlling an operational status of said engine according to said first compressor torque.

11. The method of controlling an engine according to claim 10, said vehicle air conditioning system further having an air conditioner control switch for turning on and off said air conditioner, the method further comprising:

sensing an ON state of said air conditioner control switch; and

controlling the operational status of said engine according to said first compressor torque until a predetermined period of time elapses after said air conditioner control switch is turned on.

13. A method for controlling an engine according to claim 10, the method further comprising:

sensing an ON state of said air conditioner control switch; and

controlling the operational status of said engine according to said first compressor torque before the compressor is turned on but after said air conditioner control switch is turned on.