Abstract: System, methods, and strategies for regulating charge air temperature in an intake manifold of an internal combustion engine (50) by controlling the flow rate and temperature of liquid engine coolant flowing through a liquid flow path of a charge air cooler (72) that is in heat exchange relationship with charge air entering the intake manifold over a range that provides for the charge air to be selectively heated and cooled by liquid engine coolant. The invention provides flexible control that is useful in controlling exhaust gas temperature for regeneration and/or efficiency restoration of exhaust after-treatment devices (66) as well as improved engine performance.