Vehicle cooling system

Abstract

The disclosure relates to a cooling system and a method for operating the cooling system for cooling a battery of a vehicle using a coolant circuit. The cooling circuit includes a pump device, a heat exchanger for transferring heat between a coolant and the battery, a heat exchanger for transferring heat between the coolant and the surroundings, and a heat exchanger for transferring heat between the coolant and a refrigerant circulating in a refrigerant circuit. The refrigerant circuit is designed with a heat exchanger and an associated expansion element. The refrigerant circuit includes two additional expansion elements. The first expansion element is arranged upstream of the heat exchanger and the second expansion element is arranged downstream of the heat exchanger, with regard to the direction of the refrigerant flow. The heat exchangers designed as evaporators on the refrigerant side can be operated with different pressure and temperature levels.

1 - 10 . (canceled) 
     
     
         11 . A cooling system for cooling a battery of a vehicle comprising:
 a cooling circuit for receiving a coolant therein;   a pump disposed in the cooling circuit;   a first heat exchanger in fluid communication with the pump for transferring heat between the coolant and the battery;   a second heat exchanger in fluid communication with the pump and the first heat exchanger for transferring heat between the coolant and the atmosphere; and   a third heat exchanger in fluid communication with the pump, the first heat exchanger and the second heat exchanger in the cooling circuit for transferring heat between the coolant and a refrigerant circulating through a refrigerant circuit, the refrigerant circuit in fluid communication with the third heat exchanger and including a fourth heat exchanger, a first expansion element, and a second expansion element;   wherein the first expansion element is positioned upstream of the third heat exchanger, and the second expansion element is arranged downstream of the third heat exchanger in respect of a direction of flow of the refrigerant so the third heat exchanger and the fourth heat exchanger can be operated at different pressures and temperatures.   
     
     
         12 . The cooling system according to  claim 11 , wherein the refrigerant circuit is a component of an air-conditioning system of the vehicle and the fourth heat exchanger conditions incoming air in a vehicle interior. 
     
     
         13 . The cooling system according to  claim 11 , wherein the third heat exchanger is connected in parallel with the fourth heat exchanger. 
     
     
         14 . The cooling system according to  claim 11 , wherein the third heat exchanger is connected in series with the fourth heat exchanger. 
     
     
         15 . The cooling system according to  claim 11 , wherein each of the first expansion element and the second expansion element is an adjustable expansion valve allowing the refrigerant circuit to be operated using a two-stage expansion at the third heat exchanger so a temperature at which heat transfers between the coolant and the refrigerant can be controlled independent of a temperature at which heat transfers within the fourth heat exchanger. 
     
     
         16 . The cooling system according to  claim 11 , wherein the second heat exchanger includes a fan allowing heat to be transferred from the coolant to the atmosphere. 
     
     
         17 . The cooling system according to  claim 16 , wherein the fan delivers a flow of air across a surface of the second heat exchanger. 
     
     
         18 . The cooling system of  claim 16 , wherein the fan is an adjustable speed fan allowing a variable volume of air to flow across the surface of the second heat exchanger and wherein at least the volume of air controls an amount of heat transfer in the second heat exchanger. 
     
     
         19 . The cooling system of  claim 11 , wherein at least a flow rate of the coolant controls an amount of heat transfer in the first heat exchanger and the second heat exchanger. 
     
     
         20 . The cooling system of  claim 11 , wherein a junction disposed between the second heat exchanger and the third exchanger selectively directs the coolant to the third heat exchanger or to bypass the third heat exchanger. 
     
     
         21 . A method for operating a cooling system for cooling a battery of a vehicle comprising the steps of:
 circulating a coolant through a first heat exchanger of a cooling circuit for transferring heat between the coolant and the battery;   circulating the coolant through a second heat exchanger of the cooling circuit in fluid communication with the pump and the first heat exchanger for transferring heat between the coolant and the atmosphere; and   circulating the coolant through a third heat exchanger of the cooling circuit in fluid communication with the first heat exchanger and the second heat exchanger;   wherein the third heat exchanger transfers heat between the coolant and a refrigerant circulating through a refrigerant circuit, the refrigerant circuit in fluid communication with the third heat exchanger and including a fourth heat exchanger, a first expansion element, and a second expansion element; and   wherein the first expansion element is positioned upstream of the third heat exchanger, and the second expansion element is arranged downstream of the third heat exchanger in respect of a direction of flow of the refrigerant so the third heat exchanger and the fourth heat exchanger can be operated at different pressures and temperatures.   
     
     
         22 . The method according to  claim 21 , wherein the third heat exchanger is connected in parallel to the fourth heat exchanger. 
     
     
         23 . The method according to  claim 21 , wherein each of the first expansion element and the second expansion element is an adjustable expansion valve. 
     
     
         24 . The method according to  claim 21 , wherein the refrigerant is decompressed before and after flowing into the third heat exchanger so the refrigerant undergoes a two-stage expansion across the third heat exchanger. 
     
     
         25 . The method according to  claim 21 , wherein the second heat exchanger includes a fan allowing heat to be transferred from the coolant to the atmosphere. 
     
     
         26 . The method according to  claim 25 , wherein the fan rotates at an adjustable speed allowing a variable volume of air to flow across a surface of the second heat exchanger and wherein at least the volume of air controls an amount of heat transfer in the second heat exchanger. 
     
     
         27 . The method according to  claim 26 , wherein a junction disposed between the second heat exchanger and the third exchanger selectively directs the coolant to one of the third heat exchanger and a bypass of the third heat exchanger. 
     
     
         28 . The method according to  claim 27 , wherein at ambient temperatures below about 30 degrees Celsius, a temperature of the coolant entering the battery is controlled by the speed of the fan, and the coolant, after passing through the second heat exchanger, flows through one of the bypass and the third heat exchanger after the third heat exchanger has been deactivated. 
     
     
         29 . The method according to  claim 21 , wherein at ambient temperatures between about 30 degrees Celsius and 40 degrees Celsius, an evaporation temperature of the refrigerant and a refrigerating capacity of the third heat exchanger are controlled by adjusting a cross-section of the first expansion valve and a cross section of the second expansion valve, and wherein the third heat exchanger is activated. 
     
     
         30 . The method according to  claim 21 , wherein at ambient temperatures above about 40 degrees Celsius, a temperature of the coolant entering the battery is controlled by at least one of varying an evaporation temperature of the refrigerant and varying a refrigerating capacity of the third heat exchanger, and wherein the second heat exchanger is deactivated.