Electronic expansion valve control system
AssigneeCarrier Corporation
InventorsJohn Robert Reason, Mead Robert Rusert, Douglas Herbert Morse, Thomas Edward Brendel
Life of this patent
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Abstract
A process and method for monitoring and selectively controlling the capacity and operating conditions of a refrigeration unit is disclosed. Specifically, the present invention includes the adjustment of the electronic expansion valve, and the compressor cylinder banks through the adjustment of desired superheat levels in order to bring a transport refrigeration unit within desired operating conditions.
Claims9
A process for optimizing capacity in a refrigeration unit under controlled, power limitation conditions, said process comprising the steps of:
- i monitoring the compressor discharge pressure and ambient air temperature of the refrigeration unit;
- ii determining a desired compressor discharge pressure limit;
- iii comparing said compressor discharge pressure to said desired compressor discharge pressure limit;
- and
- iv selectively increasing a desired superheat setting when said compressor discharge pressure exceeds said compressor pressure discharge limit, thereby restricting an electronic expansion valve so as to decrease a refrigerant mass flow within the refrigeration unit and to decrease power consumption of said refrigeration unit.
A process for preventing unnecessary shutdowns in a transport refrigeration unit having an engine load, said process comprising the steps of:
- i monitoring the engine coolant temperature of the transport refrigeration unit;
- ii comparing said engine coolant temperature to a preselected, desired engine coolant temperature limit;
- and
- iii selectively increasing a desired superheat setting when said engine coolant temperature exceeds said engine coolant temperature limit, thereby restricting an electronic expansion valve so as to decrease a refrigerant mass flow within the refrigeration unit and to decrease the engine load of said refrigeration unit.
A process for preventing unnecessary shutdowns in a transport refrigeration unit, said process comprising the steps of:
- i monitoring the compressor discharge temperature of the transport refrigeration unit;
- ii comparing said compressor discharge temperature to a desired, preselected compressor discharge temperature limit;
- and
- iii selectively actuating a compressor unloader when said compressor discharge temperature exceeds said compressor discharge temperature limit, thereby restricting a refrigerant mass flow of the refrigeration unit and decreasing said compressor discharge temperature of said transport refrigeration unit.
A process for preventing unnecessary shutdowns in a transport refrigeration unit, said process comprising the steps of:
- i monitoring the compressor discharge pressure of the transport refrigeration unit;
- ii comparing said compressor discharge pressure to a desired, preselected compressor discharge pressure limit;
- and
- iii selectively actuating a compressor unloader when said compressor discharge pressure exceeds said compressor discharge pressure limit, thereby restricting a refrigerant mass flow within the refrigeration unit and decreasing the compressor discharge pressure of said transport refrigeration unit.
A process for avoiding top freezing conditions in a transport refrigeration unit, said process comprising the steps of:
- i monitoring the supply air temperature of the transport refrigeration unit;
- ii comparing said supply air temperature to a desired supply air temperature limit;
- and
- iii selectively increasing a desired superheat setting when said supply air temperature falls below said supply air temperature limit, thereby restricting an electronic expansion valve so as to decrease a refrigerant mass flow of the refrigeration unit and to decrease capacity of said transport refrigeration unit.
Dependencies are inferred from the claim text.