Method and apparatus for control of propulsion system warmup based on engine wall temperature

A vehicle system, comprising:

• an internal combustion engine including an engine wall, wherein the engine wall has a wall temperature;
• a cooling system in thermal communication with the internal combustion engine;
• a controller in electronic communication with the cooling system, wherein the controller is programmed to:
• determine an engine speed of an internal combustion engine, wherein the internal combustion engine has an engine wall, and the engine wall has a wall temperature;
• determine an engine load of the internal combustion engine;
• determine a wall-reference temperature as a function of the engine load and the engine speed of the internal combustion engine;
• command the cooling system to adjust a volumetric flow rate of a coolant flowing through the internal combustion engine to maintain the wall temperature at the wall-reference temperature;
• determine that oil warming is needed;
• and
• in response to determining that oil warming is needed, apply an oil warming offset to the wall-reference temperature by subtracting an oil-warming-predetermined value from the wall-reference temperature.