A method for controlling the temperature of a cooling fluid in a cooling system and a cooling system

Abstract

Provided is a method for controlling the temperature of a cooling fluid in a cooling system comprising a cooling circuit connected to a condenser of a waste heat recovery system, a cooling pump arranged to circulate a cooling fluid through the cooling circuit and a radiator arranged for cooling the cooling fluid, a bypass circuit, a first and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid through the radiator and the bypass circuit, and the second valve unit controls the flow of cooling fluid passing through the condenser. A condenser-in temperature of the cooling fluid is determined by a first temperature sensor and an engine-in temperature of the cooling fluid is determined by a second temperature sensor. The flow of the cooling fluid is controlled by the first valve unit and/or the second valve unit based on the determined condenser-in and engine-in fluid temperatures.

1 . A method for controlling the temperature of a cooling fluid in a cooling system arranged in fluid connection with an internal combustion engine of a vehicle, the cooling system comprising a cooling circuit connected to a condenser of a waste heat recovery system, a cooling pump arranged to circulate a cooling fluid through the cooling circuit and a radiator arranged for cooling the cooling fluid, a bypass circuit, a first valve unit and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid through the radiator and the bypass circuit respectively, and the second valve unit is arranged to control the flow of cooling fluid passing through the condenser,
 wherein said method comprises:
 determining a condenser-in cooling fluid temperature by means of a first temperature sensor arranged upstream of the condenser and downstream of a first mixing point, where the cooling fluid from the radiator and bypass circuit are mixed, and an engine-in cooling fluid temperature by means of a second temperature sensor arranged upstream of the internal combustion engine and downstream of a second mixing point, where the cooling fluid from the condenser and bypass circuit are mixed; and 
 controlling the flow of the cooling fluid in the cooling system by means of the first valve unit and/or the second valve unit based on the determined condenser-in and engine-in fluid temperatures. 
   
     
     
         2 . The method according to  claim 1 , wherein the controlling step comprises comparing the determined cooling fluid temperatures with pre-defined reference cooling fluid temperatures. 
     
     
         3 . The method according to  claim 2 , wherein the controlling step comprises increasing the flow of cooling fluid through the radiator by means of the first valve unit if the engine-in cooling fluid temperature is higher than the predefined engine-in cooling fluid temperature. 
     
     
         4 . The method according to  claim 2 , wherein the controlling step comprises decreasing the flow of cooling fluid from the bypass circuit via a second return pipe to the first mixing point by means of the second valve unit, if the condenser-in cooling fluid temperature is higher than the pre-defined condenser-in cooling fluid temperature, or by increasing the flow of cooling fluid from the bypass circuit via a second return pipe to the first mixing point by means of the second valve unit, if the condenser-in cooling fluid temperature is lower than the pre-defined condenser-in cooling fluid temperature. 
     
     
         5 . The method according to  claim 1 , wherein the controlling step comprises arranging the second valve unit to adapt to a position of the first valve unit to thereby control the condenser-in and/or the engine-in fluid temperature. 
     
     
         6 . The method according to  claim 1 , wherein the determining step further comprises determining at least one further cooling fluid temperature which is selected from an engine-out, a radiator-out or a condenser-out cooling fluid temperature, or a condenser-in or a condenser-out working fluid temperature, the fluid temperatures being determined by means of a respective third temperature sensor, fourth temperature sensor, fifth temperature sensor, sixth temperature sensor and/or seventh temperature sensor. 
     
     
         7 . The method according to  claim 6 , wherein the controlling step comprises lowering the pre-defined condenser-in and engine-in cooling fluid temperatures, if at least one of the engine-out, radiator-out or condenser-out cooling fluid temperatures or the condenser-in or condenser-out working fluid temperatures exceeds a predefined value for the engine-out, a radiator-out or a condenser-out cooling fluid temperature. 
     
     
         8 . The method according to  claim 1 , wherein the controlling step further comprises predicting coming driving conditions by means of look-ahead active prediction function and controlling the condenser-in and the engine-in cooling fluid temperatures further based on the predicted coming driving conditions. 
     
     
         9 . A cooling system associated with an internal combustion engine of a vehicle, the cooling system comprising:
 a cooling circuit connected to a condenser of a waste heat recovery system;   a cooling pump arranged to circulate a cooling fluid through the cooling circuit;   a radiator arranged for cooling the cooling fluid;   a bypass circuit;   a first valve unit and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid CF through the radiator and the bypass circuit respectively, and the second valve unit is arranged to control the flow of cooling fluid passing through the condenser of the waste heat recovery system;   a first temperature sensor arranged upstream of the condenser and downstream of a first mixing point, where the cooling fluid from the radiator and bypass circuit are mixed;   a second temperature sensor arranged upstream of the internal combustion engine and downstream of a second mixing point, where the cooling fluid from the condenser and bypass circuit are mixed; and   a control unit adapted to control the first valve unit and the second valve unit so that the flow of the cooling fluid in the cooling system is controlled based on temperature values determined by the first and second temperature sensors.   
     
     
         10 . The cooling system according to  claim 9 , wherein the cooling circuit comprises at least one additional temperature sensor selected from a third temperature sensor arranged between the internal combustion engine and the first valve unit, a fourth temperature sensor arranged between the radiator and the first mixing point, a fifth temperature sensor arranged between the condenser and the second mixing point, a sixth temperature sensor arranged in the waste heat recovery system upstream of the condenser to measure the condenser-in temperature of the working fluid, or a seventh temperature sensor arranged in the waste heat recovery system downstream of the condenser to measure the condenser-out temperature of the working fluid, wherein the at least one additional temperature sensor is connected to the control unit. 
     
     
         11 . The cooling system according to  claim 9 , wherein the control unit is adapted to control the engine-in temperature of the cooling fluid in the cooling circuit by means of the first valve unit to increase the flow of cooling fluid through the radiator and/or to reduce the flow of cooling fluid passing through the bypass circuit by means of the second valve unit. 
     
     
         12 . The cooling system according to  claim 9 , wherein the cooling circuit is arranged with one cooling pump to circulate the cooling fluid through the cooling circuit. 
     
     
         13 . A system associated with an internal combustion engine of a vehicle, said system comprising:
 a cooling system comprising:
 a cooling circuit connected to a condenser of a waste heat recovery system; 
 a cooling pump arranged to circulate a cooling fluid through the cooling circuit; 
 a radiator arranged for cooling the cooling fluid; 
 a bypass circuit; 
 a first valve unit and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid CF through the radiator and the bypass circuit respectively, and the second valve unit is arranged to control the flow of cooling fluid passing through the condenser of the waste heat recovery system; 
 a first temperature sensor arranged upstream of the condenser and downstream of a first mixing point, where the cooling fluid from the radiator and bypass circuit are mixed; 
 a second temperature sensor arranged upstream of the internal combustion engine and downstream of a second mixing point, where the cooling fluid from the condenser and bypass circuit are mixed; and 
 a control unit adapted to control the first valve unit and the second valve unit so that the flow of the cooling fluid in the cooling system is controlled based on temperature values determined by the first and second temperature sensors; 
   a waste heat recovery system; and   a condenser connecting the cooling system and the waste heat recovery system.   
     
     
         14 . A vehicle comprising a cooling system, which, in turn, comprises:
 a cooling circuit connected to a condenser of a waste heat recovery system;   a cooling pump arranged to circulate a cooling fluid through the cooling circuit;   a radiator arranged for cooling the cooling fluid;   a bypass circuit;   a first valve unit and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid CF through the radiator and the bypass circuit respectively, and the second valve unit is arranged to control the flow of cooling fluid passing through the condenser of the waste heat recovery system;   a first temperature sensor arranged upstream of the condenser and downstream of a first mixing point, where the cooling fluid from the radiator and bypass circuit are mixed;   a second temperature sensor arranged upstream of the internal combustion engine and downstream of a second mixing point, where the cooling fluid from the condenser and bypass circuit are mixed; and   a control unit adapted to control the first valve unit and the second valve unit so that the flow of the cooling fluid in the cooling system is controlled based on temperature values determined by the first and second temperature sensors;   a waste heat recovery system.   
     
     
         15 . (canceled) 
     
     
         16 . A computer program product comprising a program code stored on a non-transitory computer-readable medium for controlling the temperature of a cooling fluid in a cooling system arranged in fluid connection with an internal combustion engine of a vehicle, the cooling system comprising a cooling circuit connected to a condenser of a waste heat recovery system, a cooling pump arranged to circulate a cooling fluid through the cooling circuit and a radiator arranged for cooling the cooling fluid, a bypass circuit, a first valve unit and a second valve unit, wherein the first valve unit is arranged to control the flow of cooling fluid through the radiator and the bypass circuit respectively, and the second valve unit is arranged to control the flow of cooling fluid passing through the condenser, said computer program product comprising computer instructions to cause one or more electronic control units or computers to perform the following operations:
 determining a condenser-in cooling fluid temperature by means of a first temperature sensor arranged upstream of the condenser and downstream of a first mixing point, where the cooling fluid from the radiator and bypass circuit are mixed, and an engine-in cooling fluid temperature by means of a second temperature sensor arranged upstream of the internal combustion engine and downstream of a second mixing point, where the cooling fluid from the condenser and bypass circuit are mixed; and   controlling the flow of the cooling fluid in the cooling system by means of the first valve unit and/or the second valve unit based on the determined condenser-in and engine-in fluid temperatures.   
     
     
         17 . The method according to  claim 3 , wherein the controlling step comprises decreasing the flow of cooling fluid from the bypass circuit via a second return pipe to the first mixing point by means of the second valve unit, if the condenser-in cooling fluid temperature is higher than the pre-defined condenser-in cooling fluid temperature, or by increasing the flow of cooling fluid from the bypass circuit via a second return pipe to the first mixing point by means of the second valve unit, if the condenser-in cooling fluid temperature is lower than the pre-defined condenser-in cooling fluid temperature. 
     
     
         18 . The cooling system according to  claim 10 , wherein the control unit is adapted to control the engine-in temperature of the cooling fluid in the cooling circuit by means of the first valve unit to increase the flow of cooling fluid through the radiator and/or to reduce the flow of cooling fluid passing through the bypass circuit by means of the second valve unit.