De-icing control in a vehicle heat pump system

Abstract

Methods and systems are provided for operating a dual loop heat pump system in a de-icing mode which enables the heat pump system to maintain a target rate of heat delivery to a cabin while de-icing an outside heat exchanger by leveraging waste-heat available at one or more waste-heat sources. In one example, responsive to an outside heat exchanger de-icing request and a cabin heating request, selecting a first waste-heat heat exchanger based on a temperature of the first waste-heat heat exchanger exceeding a first temperature threshold, flowing coolant to the first waste-heat heat exchanger, flowing a first portion of the coolant exiting the first waste-heat heat exchanger to a cabin heat exchanger, and flowing a second portion of the coolant exiting the first waste-heat heat exchanger to an outside heat exchanger.

1 . A method comprising:
 selecting a first waste-heat heat exchanger based on a temperature of the first waste-heat heat exchanger exceeding a first temperature threshold;   flowing coolant in a first coolant loop through the first waste-heat heat exchanger;   flowing the coolant in the first coolant loop through an evaporator heat exchanger, wherein the evaporator heat exchanger is thermally coupled to a gas cooler heat exchanger by a refrigerant loop;   flowing a first portion of the coolant in a second coolant loop exiting the gas cooler heat exchanger through a cabin heat exchanger; and   flowing a second portion of the coolant in the second coolant loop exiting the gas cooler heat exchanger through an outside heat exchanger.   
     
     
         2 . The method of  claim 1 , wherein a ratio of the first portion to the second portion is based on a cabin heating request and an outside heat exchanger de-icing request. 
     
     
         3 . The method of  claim 2 , wherein the cabin heating request comprises a target rate of cabin heat delivery, and wherein the outside heat exchanger de-icing request comprises a target rate of outside heat exchanger heat delivery. 
     
     
         4 . The method of  claim 3 , wherein the ratio of the first portion to the second portion is proportional to a ratio between the target rate of cabin heat delivery and the target rate of outside heat exchanger heat delivery. 
     
     
         5 . The method of  claim 2 , wherein the outside heat exchanger de-icing request is generated in response to an indication that the outside heat exchanger is fouled with ice. 
     
     
         6 . The method of  claim 5 , wherein the indication that the outside heat exchanger is fouled with ice comprises a determination that a rate of heat transfer between ambient air and the outside heat exchanger is below a threshold rate of heat transfer. 
     
     
         7 . The method of  claim 5 , wherein the indication that the outside heat exchanger is fouled with ice is in response to a determination that a temperature of the outside heat exchanger is below a second threshold temperature. 
     
     
         8 . The method of  claim 1 , the method further comprising:
 flowing coolant in the first coolant loop through a second waste-heat heat exchanger based on a temperature of the second waste-heat heat exchanger exceeding a second threshold temperature.   
     
     
         9 . The method of  claim 1 , the method further comprising:
 ceasing flowing coolant through the first waste-heat heat exchanger based on the temperature of the first waste-heat heat exchanger decreasing below a first threshold temperature.   
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . A vehicle heat exchange system comprising:
 a first coolant loop comprising:
 a first pump; and 
 a plurality of waste-heat heat exchangers; 
   a second coolant loop comprising:
 a second pump; 
 a cabin heat exchanger; and 
 an outside heat exchanger; 
   a refrigerant loop thermally coupling the first coolant loop with the second coolant loop; and   a controller configured with instructions stored in non-transitory memory that when executed causes the controller to:
 generate an outside heat exchanger de-icing request; 
 generate a cabin heating request; 
 responsive to the outside heat exchanger de-icing request and the cabin heating request: 
 pump coolant in the first coolant loop through one or more of the plurality of waste-heat heat exchangers via the first pump; 
 transfer heat from the first coolant loop to the second coolant loop via the refrigerant loop; and 
 pump in parallel a first fraction of coolant in the second coolant loop to the cabin heat exchanger and a second fraction of coolant in the second coolant loop to the outside heat exchanger via the second pump. 
   
     
     
         17 . The system of  claim 16 , wherein the outside heat exchanger de-icing request is generated responsive to an indication that the outside heat exchanger is fouled by ice. 
     
     
         18 . The system of  claim 16 , wherein a ratio of the first fraction of coolant to the second fraction of coolant is based on an outside heat exchanger temperature and a cabin temperature. 
     
     
         19 . The system of  claim 16 , wherein the cabin heating request is generated based on an operator climate control selection. 
     
     
         20 . The system of  claim 16 , wherein a three-way valve splits a flow of coolant in the second coolant loop into the first fraction of coolant and the second fraction of coolant. 
     
     
         21 . The method of  claim 1 , wherein routing the first portion of the second coolant in the second coolant loop to a vehicle cabin and routing the second portion of the second coolant in the second coolant loop to the outside heat exchanger comprises splitting a flow of the second coolant into the first portion and the second portion via a three-way valve. 
     
     
         22 . The method of  claim 1 , wherein the first coolant loop and the second coolant loop are not fluidically coupled.