A technique for determining the charge air temperature within an intake manifold of an internal combustion engine of a vehicle without using a dedicated temperature sensor. The technique includes identifying a non-linear dynamic model based on the physical concepts of thermal transfer and system identification technique. The charge air temperature model uses several available physical measurements from the vehicle, including inlet air temperature, engine coolant temperature, vehicle speed, manifold pressure, engine speed, exhaust gas recirculation condition, and the engine fan on/off state. The model parameters are determined based on specific vehicle characteristics, and collected data from the vehicle. The charge air temperature is predicted by the model at regular predetermined intervals from the physical measurements, the vehicle parameters and the charge air temperature from the previous time. An estimation of an initial charge air temperature when the vehicle is turned on can be obtained based on the available temperature sensor readings when vehicle is turned on and stored data of the charge temperature, and all the measured temperature readings just before the engine was turned off.