Compressor operating envelope management

• US 6,301,911 B1
• Filed: 03/26/1999
• Issued: 10/16/2001
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Reason, John Robert, Navarro de Andrade, Joao Eduardo
• Primary Examiner(s): WAYNER, WILLIAM E
• Application Number:
  US09/277,473
• Time in Patent Office: 935 Days
• Field of Search: 622/17, 622/285, 622/07, 621/962, 622/283
• US Class Current: 62/196.2
• CPC Class Codes: B60H 1/3205 Control means therefor
• 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 2001/325 of the refrigerant at a compressing unit
• CPC Class Codes: B60H 2001/3252 of the refrigerant at an evaporating unit
• CPC Class Codes: B60H 2001/3257 of the refrigerant at a compressing unit
• CPC Class Codes: B60H 2001/3263 of the refrigerant at an evaporating unit
• CPC Class Codes: B60H 2001/3266 related to the operation of the vehicle
• CPC Class Codes: B60H 2001/3285 related to an expansion unit
• CPC Class Codes: F25B 41/22 between evaporator and compressor
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25B 49/025 Motor control arrangements
• CPC Class Codes: F25D 29/003 for movable devices

Abstract

An process and method for monitoring and selectively controlling the discharge and suction pressures of a compressor within a transport unit is disclosed. Specifically, the present invention teaches the adjustment of the suction modulation valve, the compressor cylinder banks, and the engine speed solenoid in order to bring the operating compressor discharge and suction pressures within the design operating envelope.

Claims

1. A process for improving the operation of a compressor through controlling the compressor discharge pressure, said process comprising the steps of:

i monitoring the compressor discharge pressure;

ii comparing said compressor discharge pressure to a predetermined limit stored in a controller memory; and

iii selectively closing the suction modulation valve in response to a compressor discharge pressure in excess of said predetermined limit; and

iv further monitoring the compressor discharge pressure;

v selectively energizing an unloader in response to a discharge pressure above said predetermined limit.

2. A process for improving the operation of a compressor through controlling the ratio of the compressor discharge pressure to the compressor suction pressure, said process comprising the steps of:

i monitoring the compressor discharge pressure;

ii comparing said compressor discharge pressure to a predetermined limit stored in a controller memory;

iii selectively closing the suction modulation valve in response to a compressor discharge pressure in excess of said predetermined limit;

iv further monitoring the compressor discharge pressure;

v monitoring the compressor suction pressure;

vi comparing said suction pressure to a predetermined limit stored in a controller memory

vii selectively energizing an unloader in response to a suction pressure below a predetermined limit.

3. A process for improving the operation of a compressor through controlling the ratio of the compressor discharge pressure to the compressor suction pressure, said process comprising the steps of:

i monitoring the compressor discharge pressure;

ii comparing said compressor discharge pressure to a predetermined limit generated by a first algorithm stored in a controller memory;

iii selectively closing the suction modulation valve in response to a compressor discharge pressure in excess of said predetermined limit;

iv further monitoring the discharge pressure;

v further comparing said discharge pressure to a second predetermined limit generated by a second algorithm stored in a controller memory

vi selectively energizing an unloader in response to a discharge pressure above said second predetermined limit.

4. A process for improving the operation of a compressor through controlling the minimum compressor suction pressure, said process comprising the steps of:

i monitoring the compressor suction pressure;

ii comparing said compressor suction pressure to a predetermined limit stored in a controller memory;

iii selectively energizing an unloader in response to a suction pressure below said predetermined limit;

iv further monitoring the compressor suction pressure;

v comparing said compressor suction pressure to a second predetermined limit stored in a controller memory; and

vi selectively de-energizing an unloader in response to a suction pressure above said second predetermined limit.

5. A process for improving the operation of a compressor for a transport refrigeration unit through controlling the minimum compressor suction pressure, said process comprising the steps of

i monitoring the compressor suction pressure;

ii comparing said compressor suction pressure to a predetermined limit stored in a controller memory;

iii selectively energizing an unloader in response to a suction pressure below said predetermined limit;

iv further monitoring the compressor suction pressure;

v further comparing said compressor suction pressure to said predetermined limit stored in a controller memory;

vi selectively limiting the engine speed of said transport refrigeration unit in response to a suction pressure remaining below said predetermined limit.

6. The process of claim 5, comprising the further steps of:

vii further comparing said compressor suction pressure to said predetermined limit stored in a controller memory;

viii selectively opening a suction modulation valve in response to a suction pressure remaining below said predetermined limit.

7. The process of claim 6, wherein said suction modulation valve is selectively opened by a proportional-integral controller, said proportional integral controller selectively operating based upon an algorithm using the difference between the suction pressure being monitored and the predetermined limit.

8. The process of claim 7 comprising the further steps of selectively overriding the proportional-integral controller when the system current draw is greater than the maximum allowable current draw.

9. A process for improving the operation of a compressor through controlling the maximum compressor suction pressure, said process comprising the steps of:

i monitoring the compressor suction pressure;

ii comparing said compressor suction pressure to a predetermined limit stored in a controller memory;

iii selectively closing a suction modulation valve in response to a suction pressure above said predetermined limit;

iv further monitoring the compressor suction pressure;

v comparing said compressor suction pressure to a second predetermined limit stored in a controller memory; and

vi selectively opening said suction modulation valve in response to a suction pressure below said second predetermined limit.