Temperature control for turbocharged engine

This invention relates generally to the field of internal combustion engines, and more particularly to turbocharged internal combustion engines, and specifically to a method and apparatus for cooling a turbocharged locomotive engine. A cooling apparatus () and method for a turbocharged internal combustion engine (). The combustion air () exiting a turbocharger () is passed over an air-to-water intercooler () then over an air-to-air intercooler () for heat exchange with liquid coolant and with ambient air () respectively. During periods of low ambient air temperature, the combustion air may be directed through a bypass duct () around the air-to-air intercooler, and further, may be heated by the coolant in the air-to-water intercooler. A multi-speed fan () and/or shutters () may be used to control the flow of ambient air across the air-to-air intercooler. A cooling duct () provides a flow of ambient air to the fan motor () 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 () has the lowest temperature in the system and is directed to a lube oil cooler () for engine lubricant cooling.