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Automatic control method used for defrosting a heat pump for a vehicle

  • US 10,639,965 B2
  • Filed: 08/21/2018
  • Issued: 05/05/2020
  • Est. Priority Date: 03/08/2012
  • Status: Active Grant
First Claim
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1. A control method for a heat pump system for a motor vehicle, the system including a compressor for heating and compressing a refrigerant fluid, an internal heat exchanger forming a condenser in a heating mode for heating internal air by exchange with the refrigerant fluid flowing from the compressor, an expansion valve for cooling the refrigerant fluid, an external heat exchanger forming an evaporator in the heating mode for heating the refrigerant liquid flowing from the expansion valve by exchange with external air, and an accumulator interposed between the external heat exchanger and the compressor for storing the refrigerant fluid before compression, the method comprising:

  • a) in the heating mode, detecting frosting of the external heat exchanger;

    b) determining a data element representing a duration of the frosting of the heat exchanger;

    c) if the duration of the frosting of the external heat exchanger is greater than or equal to a first predetermined maximum duration, sending a command for defrosting the external heat exchanger; and

    d) if a command for defrosting the external heat exchanger is sent, starting an operation of defrosting the external heat exchanger and, according to a predefined criterion, starting an operation of defrosting the accumulator by circulating a fluid compressed by the compressor in the external heat exchanger and the accumulator,wherein, in operation a), frosting of the external heat exchanger is detected if the external air temperature is below a second predetermined temperature value and the temperature difference between the external air temperature and the temperature of the refrigerant fluid at an outlet of the external heat exchanger is above a third predetermined temperature value.

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