Abstract: A control system and method for controlling an engine (10) of an automotive vehicle having a catalyst (34) and controller (40) is set forth herein. The controller (40) is configured to determine a first exhaust flow rate and a second exhaust flow rate based on a flow rate of the exhaust gases. The controller is further configured to determine a first temperature (T1) of exhaust gases associated with the first exhaust flow rate based on a steady state temperature and an amount of heat transferred from the exhaust gases associated with the first exhaust flow rate to an exhaust system. The controller is further configured to determine a second temperature of exhaust gases associated with the second exhaust flow rate based on the steady state temperature. The controller is further configured to determine the catalytic converter temperature based on the first temperature and the second temperature.