Controlling an exhaust gas temperature of an engine. An electronic control unit receives a parameter setpoint command, monitors parameters of an engine using a plurality of sensors, receives measured engine states based on the monitored engine parameters from the plurality of sensors, generates measured engine state estimates and controlled engine state estimates using an engine observer model, determines an observer error based on a difference between the measured engine states and the measured engine state estimates, generates model corrections based on the observer error, generates a desired exhaust throttle valve position using an inverse engine model based on the parameter setpoint command, the controlled engine state estimates, and the model corrections, and adjusts a position of the exhaust throttle valve based on the desired exhaust throttle position.