Abstract: A locomotive includes an engine (12), an intercooler (16), and an oil cooler (28), each having respective cooling passages formed therein. The locomotive also includes a cooling system (10) in selective communication with the respective cooling passages for selectively providing a first coolant (56) and a second coolant (52) at a higher temperature than the first coolant to the cooling passages. A method of operating the cooling system includes providing, in a first mode, a first coolant flow (26) to the intercooler and a second coolant flow (30) to the oil cooler at a first temperature different than the first coolant flow to achieve preferential cooling of the intercooler. The method also includes providing, in a second mode, the first coolant flow to the intercooler and the second coolant flow to the oil cooler at a second temperature different than the first coolant flow to achieve preferential cooling of the oil cooler.

Abstract: A cooling apparatus (10) and method for a turbocharged internal combustion engine (12). The combustion air (16) exiting a turbocharger (18) is passed over an air-to-water intercooler (40) then over an air-to-air intercooler (42) for heat exchange with liquid coolant and with ambient air (32) respectively. During periods of low ambient air temperature, the combustion air may be directed through a bypass duct (80) around the air-to-air intercooler, and further, may be heated by the coolant in the air-to-water intercooler. A multi-speed fan (44) and/or shutters (48) may be used to control the flow of ambient air across the air-to-air intercooler. A cooling duct (68) provides a flow of ambient air to the fan motor (46) during periods of operation when the flow of ambient air over the air-to-air heat exchanger is restricted by the shutters. Coolant exiting a subcooler (28) has the lowest temperature in the system and is directed to a lube oil cooler (34) for engine lubricant cooling.

Abstract: A cooling apparatus (10) and method for a turbocharged internal combustion engine (12). The combustion air (16) exiting a turbocharger (18) is passed over an air-to-water intercooler (40) then over an air-to-air intercooler (42) for heat exchange with liquid coolant and with ambient air (32) respectively. During periods of low ambient air temperature, the combustion air may be directed through a bypass duct (80) around the air-to-air intercooler, and further, may be heated by the coolant in the air-to-water intercooler. A multi-speed fan (44) and/or shutters (48) may be used to control the flow of ambient air across the air-to-air intercooler. A cooling duct (68) provides a flow of ambient air to the fan motor (46) during periods of operation when the flow of ambient air over the air-to-air heat exchanger is restricted by the shutters. Coolant exiting a subcooler (28) has the lowest temperature in the system and is directed to a lube oil cooler (34) for engine lubricant cooling.