Method for cooling an internal combustion engine having exhaust gas recirculation and charge air cooling

Abstract

A system for cooling charge air from a turbo- or supercharger and exhaust gas recirculated from an exhaust gas recirculation valve in an internal combustion engine. The system includes a radiator and parallel charge air and exhaust gas heat exchanger units, the charge air heat exchanger unit having aluminum tubes and fins for air cooling the charge air, and the exhaust gas heat exchanger unit having stainless steel tubes and fins. The charge air heat exchanger and the exhaust gas heat exchanger units are each disposed adjacent the radiator, on the same or opposite sides. Alternatively, there is provided a pair of combined charge air cooler and exhaust gas cooler heat exchanger units, with a first heat exchanger unit having stainless steel tubes and fins, and a second heat exchanger unit having aluminum tubes and fins. The heat exchanger units are disposed on opposites sides of the radiator.

1 . A method of cooling charge air from a turbo- or supercharger and exhaust gas recirculated from an exhaust gas recirculation valve in an internal combustion engine comprising:
 providing a radiator for air cooling of liquid engine coolant from the internal combustion engine;   providing charge air and exhaust gas heat exchanger units disposed in parallel with respect to ambient air flow, the charge air heat exchanger unit having aluminum tubes and fins for air cooling the charge air, and the exhaust gas heat exchanger unit having tubes and fins made of a material resistant to higher operating temperatures than aluminum for air cooling the exhaust gas, the charge air heat exchanger and the exhaust gas heat exchanger units each being disposed adjacent a face of the radiator downstream of the radiator with respect to ambient air flow to permit ambient air to flow in series first through the radiator and subsequently through the charge air and exhaust gas heat exchanger units;   flowing ambient air in series first through the radiator and subsequently through the charge air heat exchanger unit without flowing such air through the exhaust gas heat exchanger unit and flowing ambient air in series first through the radiator and subsequently through the exhaust gas heat exchanger unit without flowing such air through the charge air heat exchanger unit;   passing the charge air from the turbo- or supercharger through the charge air heat exchanger unit to cool the charge air;   passing the exhaust gas from the exhaust gas recirculation valve through the exhaust gas heat exchanger unit to cool the exhaust gas; and   combining the cooled charge air and cooled exhaust gas for passage into an intake manifold on the engine.   
     
     
         2 . The method of  claim 1  wherein the exhaust gas heat exchanger unit has tubes and fins made of stainless steel. 
     
     
         3 . The method of  claim 1  wherein the radiator comprises two units, the charge air heat exchanger unit being disposed adjacent a face of one radiator unit and the exhaust gas heat exchanger unit being disposed adjacent a face of the other radiator unit. 
     
     
         4 . The method of  claim 3  wherein the charge air heat exchanger unit and the exhaust gas heat exchanger unit have different core styles selected from the group consisting of core depth, type of fins, fin spacing, fin count, tube spacing and tube count. 
     
     
         5 - 9 . (canceled) 
     
     
         10 . The method of  claim 3  wherein each radiator unit has a different core style selected from the group consisting of core depth, type of fins, fin spacing, fin count, tube spacing and tube count. 
     
     
         11 . The method of  claim 1  wherein the charge air and exhaust gas heat exchanger units are a first set disposed downstream of the radiator with respect to ambient air flow to permit ambient air to flow in series first through the radiator and subsequently through the first set of charge air and exhaust gas heat exchanger units, and further providing a second set of charge air and exhaust gas heat exchanger units, both heat exchanger units in the second set having aluminum tubes and fins for air cooling the charge air and the exhaust gas, the second set of charge air and exhaust gas heat exchanger units being disposed upstream of the radiator to permit ambient air to flow in series first through the second set of charge air and exhaust gas heat exchanger units and subsequently through the radiator, and wherein the partially cooled charge air from the charge air heat exchanger unit downstream of the radiator is passed through the second charge air heat exchanger unit upstream of the radiator to further cool the charge air and the partially cooled exhaust gas from the exhaust gas heat exchanger unit downstream of the radiator is passed through the second exhaust gas heat exchanger unit upstream of the radiator to further cool the exhaust gas before combining the cooled charge air and cooled exhaust gas for passage to the intake manifold of the engine. 
     
     
         12 . (canceled) 
     
     
         13 . The method of  claim 11  wherein the radiator comprises two units, the first set of charge air and exhaust gas heat exchanger units downstream of the radiator being disposed adjacent one radiator unit and the second set of charge air and exhaust gas heat exchanger units upstream of the radiator being disposed adjacent the other radiator unit. 
     
     
         14 . The method of  claim 13  wherein at least one of the charge air heat exchanger units or exhaust gas heat exchanger units has a different core style selected from the group consisting of core depth, type of fins, fin spacing, fin count, tube spacing and tube count. 
     
     
         15 . The method of  claim 13  wherein each radiator unit has a different core style selected from the group consisting of core depth, type of fins, fin spacing, fin count, tube spacing and tube count. 
     
     
         16 - 28 . (canceled) 
     
     
         29 . A system for cooling charge air from a turbo- or supercharger and exhaust gas recirculated from an exhaust gas recirculation valve in an internal combustion engine comprising:
 a radiator for air cooling of liquid engine coolant from the internal combustion engine;   charge air and exhaust gas heat exchanger units disposed in parallel with respect to ambient air flow, the charge air heat exchanger unit having aluminum tubes and fins for air cooling the charge air, and the exhaust gas heat exchanger unit having tubes and fins made of a material resistant to higher operating temperatures than aluminum for air cooling the exhaust gas, the charge air heat exchanger and the exhaust gas heat exchanger units each being disposed adjacent a face of the radiator downstream of the radiator with respect to ambient air flow to permit ambient air to flow in series first through the radiator and subsequently through the charge air heat exchanger unit without such flowing through the exhaust gas heat exchanger unit and to permit ambient air to flow in series first through the radiator and subsequently through the exhaust gas heat exchanger unit without such air flowing through the charge air heat exchanger unit;   a line for carrying charge air from the turbo- or supercharger to the charge air heat exchanger unit to cool the charge air;   a line for carrying the exhaust gas from the exhaust gas recirculation valve to the exhaust gas heat exchanger unit to cool the exhaust gas; and   a line for combining the cooled charge air and cooled exhaust gas for passage into an intake manifold on the engine.   
     
     
         30 - 32 . (canceled) 
     
     
         33 . The system of  claim 29  wherein the radiator comprises two units, the charge air heat exchanger unit being disposed adjacent a face of one radiator unit and the exhaust gas heat exchanger unit being disposed adjacent a face of the other radiator unit. 
     
     
         34 . The system of  claim 29  wherein the charge air and exhaust gas heat exchanger units are a first set disposed downstream of the radiator with respect to ambient air flow to permit ambient air to flow in series first through the radiator and subsequently through the first set of charge air and exhaust gas heat exchanger units, and further including a second set of charge air and exhaust gas heat exchanger units, both heat exchanger units in the second set having aluminum tubes and fins for air cooling the charge air and the exhaust gas, the second set of charge air and exhaust gas heat exchanger units being disposed upstream of the radiator to permit ambient air to flow in series first through the second set of charge air and exhaust gas heat exchanger units and subsequently through the radiator, and including a line for carrying partially cooled charge air from the charge air heat exchanger unit downstream of the radiator to the second charge air heat exchanger unit upstream of the radiator to further cool the charge air and a line for carrying partially cooled exhaust gas from the exhaust gas heat exchanger unit downstream of the radiator to the second exhaust gas heat exchanger unit upstream of the radiator to further cool the exhaust gas before combining the cooled charge air and cooled exhaust gas for passage to the intake manifold of the engine. 
     
     
         35 . The system of  claim 34  wherein the radiator comprises two units, the first set of charge air and exhaust gas heat exchanger units downstream of the radiator being disposed adjacent one radiator unit and the second set of charge air and exhaust gas heat exchanger units upstream of the radiator being disposed adjacent the other radiator unit.