Internal combustion engine coolant flow control

A method for controlling an internal combustion engine including an engine block, a combustion cylinder including a cylinder wall, engine oil and engine coolant, comprising:

• modeling the internal combustion engine as a plurality of heat transfers;
• defining a plurality of temperature state equations based upon the plurality of heat transfers;
• measuring a plurality of temperature state variables;
• implementing, within a controller, a thermal state model comprising the plurality of temperature state equations including receiving the plurality of temperature state variables and providing an estimated cylinder wall temperature;
• and
• controlling engine coolant flow in the internal combustion engine based upon the estimated cylinder wall temperature.

An apparatus for controlling an internal combustion engine including an engine block, a combustion cylinder including a cylinder wall, engine oil and engine coolant, comprising:

• an engine coolant pump;
• an engine block temperature sensor for measuring an engine block temperature;
• an engine coolant out temperature sensor for measuring an engine coolant out temperature;
• an engine oil temperature sensor for measuring an engine oil temperature;
• and
• a control module executing a thermal state model comprising the engine block temperature, the engine coolant out temperature and the engine oil temperature as state variable inputs, the thermal state model comprising a plurality of temperature state equations including a cylinder wall temperature state equation comprising a combustion gas to a cylinder wall heat transfer term based upon a combustion adiabatic efficiency, the thermal state model providing an estimated cylinder wall temperature, the control module controlling the engine coolant pump based upon the estimated cylinder wall temperature.