In accordance with an embodiment of the present invention, a method of
controlling an internal combustion engine system having an internal
combustion engine is disclosed. The internal combustion engine includes
an engine block defining a plurality of combustion chambers, an intake
air system in fluid communication with the combustion chambers and
providing intake air thereto, an exhaust gas system in fluid
communication with the combustion chambers and carrying exhaust gas
therefrom, a cooling system having a cooling fluid circulated therein and
a recirculated gas system in fluid communication with the exhaust gas
system and intake air system wherein a portion of the exhaust gas is
routed from the exhaust gas system to the intake air system. The method
includes sensing at least two internal combustion engine system operating
parameters, inputting sensed operating parameters into a controller,
storing at least one predetermined constant in the controller,
determining a cooling fluid heat threshold using predetermined logic with
the controller in response to the at least two internal combustion engine
operating parameters and the at least one predetermined constant, and
controlling the internal combustion engine system in a predetermined
manner in response to reaching the cooling fluid heat threshold.