Cooling System with Isolated Cooling Circuits

Abstract

A cooling system for an internal combustion engine, comprising a first, high temperature, cooling circuit coupled to an engine for cooling the engine, where a first coolant circulates in the first circuit; and a second, low temperature, cooling circuit coupled to a plurality of devices for cooling the plurality of devices, where a second coolant circulates in the second circuit, the second cooling circuit includes a plurality of radiator segments, the coolant circulating in the second cooling circuit may exit at different radiator segments of the plurality of radiator segments producing coolant streams of different cooling temperatures for cooling different devices of the plurality of devices.

1 . A cooling system for an internal combustion engine, comprising
 a first, high temperature, cooling circuit coupled to an engine for cooling the engine, where a first coolant circulates in the first circuit; and   a second, low temperature, cooling circuit coupled to a plurality of devices for cooling the plurality of devices, where a second coolant circulates in the second circuit, and where the second cooling circuit includes a plurality of radiator segments, the coolant circulating in the second cooling circuit exiting at different radiator segments of the plurality of radiator segments producing coolant streams of different cooling temperatures for cooling different devices of the plurality of devices.   
   
   
       2 . The cooling system of  claim 1 , wherein the plurality of radiator segments are positioned in a path of a common stream of air flow. 
   
   
       3 . The cooling system for an internal combustion engine of  claim 1 , wherein the coolant of the first cooling circuit does not mix with the coolant of the second cooling circuit. 
   
   
       4 . The cooling system according to  claim 1 , wherein the first cooling circuit includes at least a radiator for cooling the coolant circulating in the first cooling circuit. 
   
   
       5 . The cooling system of  claim 3 , wherein the radiator of the first cooling circuit is positioned in the path of an air flow downstream from the plurality of radiator segments of the second cooling circuit. 
   
   
       6 . The cooling system of  claim 1 , wherein the plurality of radiator segments of the second cooling circuit include at least two radiator segments, where the coolant circulating in the second cooling circuit exits at each of the two radiator segments to produce coolant streams of two different temperatures. 
   
   
       7 . The cooling system of  claim 1 , wherein the plurality of radiator segments of the second cooling circuit includes at least three radiator segments, where the coolant circulating in the second cooling circuit exits at each of the three radiator segments to produce coolant streams of three different temperatures. 
   
   
       8 . The cooling system of  claim 1 , wherein the first cooling circuit includes at least a coolant pump for circulating the coolant in the first cooling circuit, and where the second cooling circuit includes at least a coolant pump for circulating the coolant in the second cooling circuit. 
   
   
       9 . The cooling system of  claim 8 , wherein the coolant pump of the second cooling circuit is positioned downstream of the devices and upstream of the radiator segments, the coolant exiting the coolant pump first traveling to the radiator segments and then to the plurality of devices of the second cooling circuit. 
   
   
       10 . The cooling system of  claim 1 , wherein the second cooling circuit includes a bypass for allowing the coolant circulating in the second cooling circuit to bypass the plurality of radiator segments. 
   
   
       11 . The cooling system of  claim 1 , wherein the first cooling circuit cools a high temperature EGR cooler, and the second cooling circuit cools a low temperature EGR cooler. 
   
   
       12 . The cooling system of  claim 1 , wherein the second cooling circuit includes a condenser positioned in a path of air flow. 
   
   
       13 . The cooling system of  claim 1 , wherein the cooling system includes a condenser positioned away from a path of air flow. 
   
   
       14 . The cooling system of  claim 1 , wherein rates of coolant flow passing through each of the plurality of devices of the second cooling circuit are less than or equal to 15 grams per minute. 
   
   
       15 . The cooling system of  claim 1 , wherein coolant flow rates of the second cooling circuit are less than or equal to 6 grams per minute. 
   
   
       16 . A cooling system for an internal combustion engine, comprising
 a first, high temperature, cooling circuit coupled to an engine and an high temperature EGR cooler for cooling the engine and the high temperature EGR cooler, where a first coolant circulates in the first cooling circuit, the first cooling circuit includes a main coolant pump for circulating the coolant in the first cooling circuit and a main radiator for cooling the coolant circulating in the first cooling circuit, the main coolant pump is positioned downstream of the main radiator and upstream of the engine and the high temperature EGR cooler in the path of the circulating coolant, the engine and the high temperature EGR are arranged in parallel in the path of the coolant circulating in the first cooling circuit with respect to each other;   a second, low temperature, cooling circuit coupled to a plurality of devices for cooling the plurality of devices, where a second coolant circulates in the second cooling circuit, where the second cooling circuit includes an auxiliary coolant pump and a condenser, where the second cooling circuit includes three radiator segments: a warm temperature radiator, a intermediate temperature radiator, and a low temperature radiator, arranged successively in the path of the coolant circulating in the second cooling circuit, where the low temperature radiator is downstream of the intermediate temperature radiator, and the intermediate temperature radiator is downstream of the warm temperature radiator, where the circulating coolant of the second cooling circuit exits the warm temperature radiator to form a first a coolant stream with a first coolant temperature, exits the intermediate temperature radiator to form a second coolant stream with a second coolant temperature, exits the low temperature radiator to form a third coolant stream with a third coolant temperature, where the temperature of the first coolant stream is higher than the temperature of the second coolant stream, and the temperature of second coolant stream is higher than the temperature of the third coolant stream, where the first coolant stream further circulates to a transmission cooler to cool the transmission cooler, the second coolant stream further circulates to a low temperature EGR cooler to cool the low temperature EGR cooler, the third coolant stream further circulates to a fuel cooler and a charged air cooler to cool the fuel cooler and the charged air cooler, where coolant exiting each of the plurality of devices of the second cooling circuit circulates to the auxiliary coolant pump before circulates further to the plurality of radiator segments, and where the second cooling circuit includes a bypass for the coolant circulating in the second coolant circuit to bypass the plurality of radiator segments; where a common stream of air flow flows pass the first condenser, the plurality of radiators of the second cooling circuit, and the radiator of the first cooling circuit, where the first condenser is upstream of the low temperature radiator, the low temperature radiator is upstream of the intermediate temperature radiator, the intermediate temperature radiator is upstream of the warm temperature radiator, the warm temperature radiator is upstream of the main radiator of the first cooling circuit.   
   
   
       17 . A method for cooling an internal combustion engine of a vehicle, comprising:
 circulating coolant through a first cooling circuit thermally coupled to combustion chambers of the engine, the first cooling circuit including at least a radiator;   circulating coolant through a second cooling circuit thermally coupled to a plurality of devices, the second cooling circuit including a plurality of radiator segments, where the coolant is pumped via a pump coupled upstream of a radiator and downstream of the devices, where the coolant of the first cooling circuit does not mix with coolant of the second cooling circuit;   distributing coolant in the second circuit to the plurality of devices at different temperatures via the plurality of radiators in the second circuit; and   flowing a common stream of cooling air over at least the radiator in the first cooling circuit and at least one of the plurality of radiator segments in the second cooling circuit.   
   
   
       18 . The method of  claim 17  wherein the radiator of the first cooling circuit and the plurality of radiator segments of the second cooling circuit are positioned in a common stream of cooling air, with the said radiator of the radiator of the first cooling circuit downstream of the plurality of radiators; and the said plurality of radiator segments positioned successively in the path of the common stream of cooling air.