Method of predicting nitrogen dioxide emission from engine

A method of predicting nitrogen dioxide emission from an engine, for predicting an amount of nitrogen dioxide among nitrogen oxides (NOx) emitted from the engine, the method comprising:

• an initial nitrogen dioxide formation prediction operation of predicting an amount of nitrogen dioxide which is originally formed in the engine using a nitrogen dioxide formation model by an electronic control unit (ECU) while engine combustion is underway,
• a nitrogen dioxide reduction prediction operation of determining an amount of nitrogen dioxide which is reduced to nitrogen monoxide using a reverse reaction of the nitrogen dioxide formation model by the ECU based on the amount of formed nitrogen dioxide in the initial nitrogen dioxide formation prediction operation, and
• a final nitrogen dioxide emission determination operation of determining an amount of nitrogen dioxide which is generated by the engine by the ECU based on a difference between the amount of formed nitrogen dioxide and the amount of reduced nitrogen dioxide,
• wherein, in the initial nitrogen dioxide formation prediction operation, an engine operating parameter related to formation of nitrogen dioxide is applied to a radical in the nitrogen dioxide formation model by the ECU.

A method of predicting nitrogen dioxide emission from an engine, for predicting an amount of nitrogen dioxide among nitrogen oxides (NOx) emitted from the engine, the method comprising:

• an initial nitrogen dioxide formation prediction operation of predicting an amount of nitrogen dioxide which is originally formed in the engine using a nitrogen dioxide formation model while engine combustion is underway,
• a nitrogen dioxide reduction prediction operation of determining an amount of nitrogen dioxide which is reduced to nitrogen monoxide using a reverse reaction of the nitrogen dioxide formation model based on the amount of formed nitrogen dioxide in the initial nitrogen dioxide formation prediction operation, and
• a final nitrogen dioxide emission determination operation of determining an amount of nitrogen dioxide which is generated by the engine based on a difference between the amount of the formed nitrogen dioxide and the amount of reduced nitrogen dioxide,
• wherein, in the nitrogen dioxide reduction prediction operation, an engine operating parameter related to reduction of nitrogen dioxide and an ambient dilution state of a combustion product in a cylinder of the engine are applied to a radical in the reverse reaction of the nitrogen dioxide formation model.