Method and system for coolant temperature control in a vehicle propulsion system

A vehicle propulsion system, the system comprising:

• a prime mover having a coolant inlet and a coolant outlet;
• a coolant control valve having a valve inlet in communication with the prime mover coolant outlet, a first valve outlet, and a second valve outlet;
• a bypass flow path in communication with first valve outlet and the prime mover coolant inlet;
• a heat exchange flow path in communication with the second valve outlet and the prime mover inlet;
• a heat exchanger in the heat exchange flow path;
• a first temperature sensor in the bypass flow path for generating a first temperature signal;
• a second temperature sensor in the heat exchange flow path for generating a second temperature signal;
• a third temperature sensor at the prime mover coolant inlet for generating a third temperature signal;
• and
• a controller in communication with the first temperature sensor for receiving the first temperature signal, the second temperature sensor for receiving the second temperature signal, the third temperature sensor for receiving the third temperature signal, and the coolant control valve for providing a coolant control valve command signal to the coolant control valve, wherein the controller comprises a closed loop controller with a gain coefficient, and wherein the controller normalizes the gain coefficient, and wherein the controller is further in communication with the coolant control valve and controls the coolant control valve based upon the normalized gain coefficient.