Piston temperature model using a physics-based split multi-model approach

An engine, comprising:

• a plurality of pistons configured to be actuated by combustion reactions within the engine;
• a plurality of cylinders, each cylinder being configured to house a corresponding piston of the plurality of pistons and form a containment boundary for a corresponding combustion reaction of the combustion reactions;
• at least one fuel injector configured to inject fuel into the plurality of cylinders, where the fuel is mixed with air disposed in the plurality of cylinders to form an air-fuel mixture;
• a plurality of spark plugs, each spark plug being configured to ignite the air-fuel mixture in a corresponding cylinder to initiate the combustion reactions;
• a plurality of piston cooling jets configured to spray engine oil;
• and
• an Electronic Control Unit (ECU) configured to:
• receive an engine oil temperature;
• receive a current coolant temperature;
• receive a current spark value and a calibrated spark value for each spark plug of the plurality of spark plugs;
• receive a current engine speed and a current engine torque during an associated combustion reaction of the combustion reactions;
• determine a non-firing piston temperature for each piston from the engine oil temperature;
• determine a coolant temperature modifier from the current coolant temperature;
• determine a combustion phase modifier for each piston from the current spark value and the calibrated spark value;
• determine a firing piston temperature for each piston from the current engine speed and the current engine torque
• output a predicted piston temperature for each piston based on the non-firing piston temperature, the firing piston temperature, the coolant temperature modifier, and the combustion phase modifier;
• coordinate operations of the spark plugs and the at least one fuel injector based on the predicted piston temperature.