Displacement control apparatus for variable displacement compressor, displacement control method and compressor module

• US 6,484,520 B2
• Filed: 02/27/2001
• Issued: 11/26/2002
• Est. Priority Date: 02/28/2000
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
• Original Assignee: Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
• Inventors: Kawaguchi, Masahiro, Suitou, Ken, Sonobe, Masanori
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US09/794,807
• Publication Number:
  US 20010017036A1
• Time in Patent Office: 637 Days
• Field of Search: 621/33, 622/284, 622/285, 622/281, 622/30, 622/43, 623/231, 622/283
• 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 2001/3266 related to the operation of the vehicle
• CPC Class Codes: B60H 2001/3275 to control the volume of a compressor
• CPC Class Codes: F04B 2027/1854 External parameters
• CPC Class Codes: F04B 2201/1202 Torque on the axis
• CPC Class Codes: F04B 27/1804 Controlled by crankcase pressure
• CPC Class Codes: F25B 27/00 Machines, plants or systems, using particular sources of energy F25B30/06 takes precedence
• CPC Class Codes: F25B 49/022 Compressor control arrangements

Abstract

A displacement control apparatus controls the displacement of a variable displacement controller. A drive shaft of the compressor is driven by an engine. Torque acting on the drive shaft represents the displacement. The apparatus includes a control valve, an air conditioner controller and a compressor controller. The control valve changes the compressor displacement. The air conditioner controller produces a torque setting signal, which represents a target torque, to the compressor controller. The compressor controller changes the valve opening based on the torque setting signal such that the actual load torque matches the target torque value. Accordingly, the compressor is controlled according to the torque. The air conditioner controller may send the torque setting signal to an engine controller, which eliminates the need for load torque maps.

Claims

1. A displacement control apparatus for controlling the discharge displacement of a variable displacement compressor, wherein the compressor is incorporated in a refrigerant circuit of a vehicle air conditioner and includes a drive shaft, wherein a load torque is imposed on the drive shaft by driving the drive shaft with an external drive source, and a change in the load torque reflects the control of the discharge displacement, the displacement control apparatus comprising:

a control valve for changing the displacement of the compressor by changing the valve opening degree;

a first controller, which is provided outside the compressor, for sending a torque setting signal, which indicates a set torque for controlling the discharge displacement of the compressor; and

a second controller for receiving the torque setting signal sent from the first controller, wherein the controller computes an index for changing the opening degree of the control valve based on the torque setting signal so that the load torque of the compressor is changed to the set torque, wherein the index indicates the pressure difference between the pressures at two pressure monitoring points in the refrigerant circuit, wherein the opening degree is changed by changing the pressure difference to a target pressure difference which corresponds to the set torque, and as a result, the control valve opening degree is controlled to change the displacement of the compressor.

2. The displacement control apparatus according to claim 1, wherein the second controller is a compressor controller mounted on the compressor.

3. The displacement control apparatus according to claim 1 further comprising an air conditioner controller for controlling the air conditioner, and a detection device, which is connected to the air conditioner controller, for detecting information concerning the refrigerant performance required of the refrigerant circuit of the air conditioner, wherein the air conditioner controller determines the set torque based on the information.

4. The displacement control apparatus according to claim 2 further comprising an air conditioner controller for controlling the air conditioner, and a detection device, which is connected to the air conditioner controller, for detecting information concerning the refrigerant performance required of the refrigerant circuit of the air conditioner, wherein the air conditioner controller determines the set torque based on the information.

5. The displacement control apparatus according to claim 2, wherein the external drive source is an engine, wherein the apparatus further comprises an engine controller for controlling the engine, wherein the first controller also sends the torque setting signal to the engine controller.

6. The displacement control apparatus according to claim 3, wherein the external drive source is an engine, wherein the apparatus further comprises an engine controller for controlling the engine, wherein the first controller also sends the torque setting signal to the engine controller.

7. The displacement control apparatus according to claim 6, wherein the first controller is the air conditioner controller or the engine controller.

8. The displacement control apparatus according to claim 2, wherein the external drive source is an engine, wherein the apparatus further comprises:

an air conditioner controller for controlling the air conditioner;

a first detecting device, which is connected to the air conditioner controller, for detecting the information concerning the refrigerant performance required of the refrigerant circuit of the air conditioner, wherein a first set torque is calculated by the air conditioner controller based on the information detected by the first detecting device;

an engine controller for controlling the engine; and

a second detecting device, which is connected to the engine controller, for detecting the information concerning a load imposed on the engine, wherein a second set torque is determined by the engine controller based on the information detected by the second detecting device, wherein the first controller determines the torque setting signal based on one of the first set torque and second set torque.

9. A displacement control method for controlling the discharge displacement of a variable displacement compressor, wherein the compressor is incorporated in a refrigerant circuit of a vehicle air conditioner and includes a drive shaft, wherein a load torque is imposed on the drive shaft by driving the drive shaft with an external drive source, and a change in the load torque reflects the control of the discharge displacement, the method comprising:

determining a set torque for controlling the displacement of the compressor outside the compressor;

transmitting a torque setting signal indicating the set torque to the compressor; and

changing the load torque to the set torque by controlling the discharge displacement of the compressor based on the torque setting signal, wherein the step of changing the load torque to the set torque comprises;

detecting a pressure difference between the pressures at two pressure monitoring points in the refrigerant circuit, wherein the pressure difference reflects the load torque; and

changing the pressure difference between the two pressure monitoring points to a target pressure difference, wherein the target pressure difference corresponds to the set torque.

10. The method according to claim 9, wherein the set torque is determined based on information concerning the cooling performance required of the air conditioner or information reflecting the load imposed on the external drive source.

11. The method according to claim 9 further comprising computing the load imposed on the external drive source by the compressor using the set torque.

12. The method according to claim 10 further comprising computing the load imposed on the external drive source by the compressor using the set torque.

13. A displacement control method for controlling the discharge displacement of a variable displacement compressor, wherein the compressor is incorporated in a refrigerant circuit of a vehicle air conditioner and includes a drive shaft, wherein a load torque is imposed on the drive shaft by driving the drive shaft with an external drive source, and a change in the load torque reflects the control of the discharge displacement, the method comprising:

determining a set torque for controlling the displacement of the compressor outside the compressor;

transmitting a torque setting signal indicating the set torque to the compressor; and

changing the load torque to the set torque by controlling the discharge displacement of the compressor based on the torque setting signal, wherein the step of changing the load torque to the set torque comprises;

detecting a first pressure difference between the pressures at two pressure monitoring points in the refrigerant circuit;

detecting a second pressure difference, which is different from the first pressure difference, between the two pressure monitoring points, wherein the first and second pressure differences reflect the load torque; and

changing the first and second pressure differences to target pressure differences, wherein the target pressure differences correspond to the set torque.

14. A compressor module comprising:

a compressor, which forms part of a refrigerant circuit in a vehicle air conditioner, wherein the compressor includes a drive shaft on which a load torque is imposed by an external drive source;

a control valve located in the compressor for changing the discharge displacement of the compressor by controlling the valve opening degree; and

a compressor controller mounted on the compressor, wherein the compressor controller receives a torque setting signal indicating a set torque from outside the compressor, wherein the compressor controller computes an index for changing the control valve opening degree based on the torque setting signal so that the load torque is changed to the set torque, wherein the index indicates the pressure difference between the pressures at two pressure monitoring points in the refrigerant circuit, wherein the opening degree is changed by changing the pressure difference to a target pressure difference which corresponds to the set torque, wherein the compressor controller sends an instruction to the control valve according to the index, and as a result, the control valve opening degree is controlled to control the displacement of the compressor.

15. The compressor module according to claim 14 further comprising:

a crank chamber through which the drive shaft passes;

a cam plate that inclines with respect to the drive shaft and rotates integrally with the drive shaft in the crank chamber; and

a piston, which is cooperatively coupled with the cam plate, wherein the piston reciprocates in a compressing chamber, wherein the stroke of the piston reflects a compressor displacement and is changed by a change in the inclination of the cam plate in accordance with the pressure of the crank chamber,

wherein the control valve controls the pressure in the crank chamber by adjusting the valve opening degree and the compressor controller uses an equation representing the relationship between a plurality of variables and a set torque to compute an index of the valve opening degree for a set torque, and the variables include the discharge pressure of the compressor, the rotational speed of the drive shaft and the discharge gas flow rate.

16. The compressor module according to claim 15 further comprising an information detector for determining values of the variables.

17. The compressor module according to claim 15, wherein the variables include the suction pressure.

18. The compressor module according to claim 15, wherein the refrigerant circuit has a condenser connected to the compressor through a high pressure pipe, and the compressor discharges refrigerant gas through the compressing chamber in accordance with the stroke of the piston, and the compressor has a discharge chamber connected to the high pressure pipe, the high pressure pipe being located between the discharge chamber and the condenser, wherein a restrictor is located in the high pressure pipe, and the control valve includes a pressure difference detector for mechanically detecting the pressure difference between the pressures across the restrictor, the valve opening degree being adjusted based on the pressure difference detected by the pressure difference detector.

19. A compressor module comprising:

a compressor, which forms part of a refrigerant circuit in a vehicle air conditioner, wherein the compressor includes a drive shaft on which a load torque is imposed by an external drive source;

a control valve located in the compressor for changing the discharge displacement of the compressor by controlling the valve opening degree, wherein the control valve includes a first pressure difference detector and a second pressure difference detector for mechanically detecting a first pressure difference and a second pressure difference which is different from the first pressure difference, respectively, wherein the first and second pressure differences are the pressure differences between the pressures at two pressure monitoring points in the refrigerant circuit, wherein the second pressure difference is based on the discharge pressure of the compressor; and

a compressor controller mounted on the compressor, wherein the compressor controller receives a torque setting signal indicating a set torque from outside the compressor, wherein the compressor controller computes an index for changing the control valve opening degree based on the torque setting signal so that the load torque is changed to the set torque, wherein the opening degree is adjusted based on the index by a fixed relationship between the first pressure difference and the second pressure difference, wherein the compressor controller sends an instruction to the control valve according to the index, and as a result, the control valve opening degree is controlled to control the displacement of the compressor.