Variable capacity compressor

• US 6,863,503 B2
• Filed: 09/03/2002
• Issued: 03/08/2005
• Est. Priority Date: 09/06/2001
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Original Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Inventors: Ueda, Motohiko, Matsuda, Mikio
• Primary Examiner(s): Yu, Justine R.
• Assistant Examiner(s): Rodriguez, William H.
• Application Number:
  US10/232,306
• Publication Number:
  US 20030044289A1
• Time in Patent Office: 917 Days
• Field of Search: 417/222.1, 417/222.2, 417/223, 417/230
• US Class Current: 417/222.1
• 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

Abstract

A variable capacity compressor like a swash plate type where a pressurized fluid is fed to a control pressure chamber such as a swash plate chamber to apply a backpressure to a piston etc. and the backpressure is changed by the capacity control valve, wherein the valve is streamlined and reduced in cost by providing a simple valve such as a two-way solenoid valve as a capacity control valve in a feed path to or discharge path from the control pressure chamber. By controlling the duty ratio of the valve, it is possible to smoothly change the capacity of the compressor. Further, a torque sensor is provided at a drive shaft, and the valve is controlled by a control unit to change the discharge capacity of the compressor in accordance with that detection value.

Claims

1. A variable capacity compressor changed in discharge capacity by changing a pressure of a fluid acting in a control pressure chamber, wherein:

a valve for just opening and closing a passage is provided as a capacity control valve at one of a feed path for feeding a high-pressure fluid to said control pressure chamber and a discharge path for discharging the fluid from said control pressure chamber to a low-pressure side;

a constricted passage is formed at the other of the feed path and the discharge path;

a torque sensor is attached to a drive shaft and its detection value is input to a control unit, and the valve is operated by said control unit in accordance with the detection value of the torque sensor;

said fluid is a refrigerant in an air-conditioning system;

said air-conditioning system is installed in a vehicle;

said control unit is linked with a control unit of said vehicle or an engine mounted in the same, and the discharge capacity of said compressor is changed in accordance with an allowable value of torque for driving said compressor determined in accordance with at least an operating state of said vehicle or engine;

a control program to be executed by said control unit includes;

a step of starting control and setting a duty ratio of said valve to a predetermined value, for substantially minimizing the discharge capacity of the compressor at the time of engine startup;

a step of judging if said air-conditioning system is in an operating state;

a step of reading a detection value of said torque sensor when said air-conditioning system is in an operating state;

a step of reading an allowable value of torque from said vehicle or engine control unit;

a step of judging if an absolute value of the difference between a detection value of said torque and said allowable value is smaller than a predetermined value;

a step of maintaining a duty ratio of a drive signal supplied to said valve when said absolute value of the difference is smaller than a predetermined value;

a step of judging if said allowable value of the torque is smaller than said detection value when said absolute value of the difference is larger than a predetermined value;

a step of increasing said duty ratio of the valve by exactly a predetermined amount when said allowable value of the torque is smaller than said detection value; and

a step of reducing said duty ratio of the valve by exactly a predetermined amount when said allowable value of the torque is larger than said detection value.

2. A variable capacity compressor as set forth in claim 1, wherein said high-pressure fluid is pressurized fluid in a discharge chamber.

3. A variable capacity compressor as set forth in claim 1, wherein a two-way solenoid valve is used as said valve.

4. A variable capacity compressor as set forth in claim 1, wherein said control unit is configured to control a duty ratio of said valve.

5. A variable capacity compressor as set forth in claim 1, wherein said control pressure chamber is a swash plate chamber.

6. A variable capacity compressor changed in discharge capacity by changing a pressure of a fluid acting in a control pressure chamber, wherein:

a valve for just opening and closing a passage is provided as a capacity control valve at one of a feed path for feeding a high-pressure fluid to the control pressure chamber and a discharge path for discharging the fluid from the control pressure chamber to a low-pressure region of the compressor;

a constricted passage is formed at the other path;

a torque sensor is attached to a drive shaft, and its detection value is input to a control unit, and the valve is operated by the control unit in accordance with the detection value of the torque sensor;

the fluid is a refrigerant in an air-conditioning system;

the air-conditioning system is installed in a vehicle, and the control unit is linked with a controller of the vehicle or a controller of an engine mounted in the vehicle;

the discharge capacity of the compressor is changed in accordance with an allowable value of torque for driving the compressor, and the allowable value of torque is determined in accordance with at least an operating state of the vehicle or engine; and

a control program to be executed by the control unit includes;

controlling the valve to substantially minimize the discharge capacity of the compressor at the time of engine startup;

judging whether the air-conditioning system is in an operating state;

reading the detection value of the torque sensor when the air-conditioning system is in an operating state;

reading the allowable value of torque from the vehicle or engine controller;

judging whether an absolute value of the difference between the detection value of the torque and the allowable value is smaller than a predetermined value;

maintaining the state of the valve when the absolute value of the difference is smaller than a predetermined value;

judging whether the allowable value of the torque is smaller than the detection value when the absolute value of the difference is larger than a predetermined value;

increasing the discharge capacity of the compressor by a predetermined amount when the allowable value of the torque is smaller than the detection value; and

reducing the discharge capacity of the compressor by a predetermined amount when the allowable value of the torque is larger than the detection value.