Cooling system for a vehicle driven by a combustion engine

Abstract

A cooling system in a vehicle ( 1 ) powered by a combustion engine ( 2 ). A first line circuit ( 4 ) for cooling the combustion engine ( 2 ) and a second line circuit ( 5 ) which receives coolant from the first line circuit ( 4 ) for cooling at least one medium in a heat exchanger ( 14 a , 14 b ). The second line circuit ( 5 ) includes a line ( 5 b ) with an extra radiator ( 9 ) and a bypass line ( 5 c ) with a valve ( 12 ) by which it is possible to distribute the coolant flow between the parallel lines ( 5 b , 5 c ). A control unit ( 13 ) controls the valve ( 12 ) so that it leads at least a major part of the coolant through the line ( 5 b ) with the extra radiator ( 9 ) when there is need for extra cooling of the medium in the heat exchanger ( 14 a , 14 b ) and so that it leads at least a major part of the coolant through the bypass line ( 5 c ) when there is no need for extra cooling of the medium in the heat exchanger ( 14 a , 14 b ).

1 - 10 . (canceled) 
     
     
         11 . A cooling system for a vehicle which is powered by a combustion engine, the cooling system comprising:
 a first line circuit for circulating a circulating coolant intended to cool the combustion engine, a coolant pump at the first line circuit for circulating the coolant in the first line circuit, a first radiator for the first line circuit for cooling the coolant in the first line circuit;   a second line circuit connected to the first line circuit at a receiving location for the second line circuit receiving the circulating coolant from the first line circuit, the second line circuit being connected to the first line circuit at a returning location spaced from the receiving location for returning the coolant to the first line circuit;   the second line circuit comprising a radiator line provided with a second radiator for cooling the coolant in the radiator line, a bypass line in a parallel with the radiator line in the second line circuit;   a valve which distributes the coolant flow in the second line circuit between the parallel radiator and bypass lines; the valve being situated in the bypass line, and the bypass line is configured such that the coolant is led with a lower flow resistance through the bypass line than through the radiator line with the extra radiator when the valve is placed in an open position thereof;   at least one heat exchanger downstream of the parallel radiator and bypass lines in the flow of coolant and in which the coolant cools a medium and the heat exchanger is upstream of the returning location;   and a control unit controlling the valve to lead at least a major part of the coolant flow through the radiator line with the second radiator when the control unit determines need for extra cooling of the medium in the heat exchanger or to lead at least a major part of the coolant flow through the bypass line when the control unit determines no need for extra cooling of the medium in the heat exchanger.   
     
     
         12 . A cooling system according to  claim 11 , wherein the second line circuit comprises a temperature sensor for detecting the temperature of the medium; the control unit is operable to receive information from the sensor and to control the valve so that at least a major part of the coolant flow is led through the radiator line with the second radiator when the medium is at a temperature above a highest acceptable temperature. 
     
     
         13 . A cooling system according to  claim 11 , wherein the second line circuit comprises a temperature sensor for detecting the temperature of the coolant; the control unit is operable to receive information from the sensor and to control the valve so that at least a major part of the coolant flow is led through the radiator line with the second radiator when the coolant is at a temperature above a highest acceptable temperature. 
     
     
         14 . A cooling system according to  claim 11 , wherein the second line circuit comprises at least two of the heat exchangers, each for cooling a respective medium. 
     
     
         15 . A cooling system according to  claim 14 , wherein the heat exchangers are arranged in parallel in the second line circuit. 
     
     
         16 . A cooling system according to  claim 14 , wherein the heat exchangers are arranged in series in the second line circuit. 
     
     
         17 . A cooling system according to  claim 11 , wherein the second line circuit receives coolant from the first line circuit at the receiving location and returns the coolant to the first line circuit at the returning location, the second line circuit is configured such that the coolant is at a higher pressure at the receiving location than at the returning location. 
     
     
         18 . A cooling system according to  claim 11 , wherein the second line circuit comprises a fan positioned for blowing air over the second radiator and the control unit activates the fan to provide a cooling air flow through the second radiator when the control unit determines there is need for extra cooling of the medium in the heat exchanger.