Patent ID: 8280647

Claim:
A method of monitoring at least one process state of an internal combustion engine having a combustion chamber, the method comprising: measuring compositions of educts (m a , m f ) entering a combustion chamber; determining, based on the compositions of the educts (m a , m f ), a composition of a product produced by the combustion chamber; determining mechanical power (P mech ) generated by the internal combustion engine; determining a value of at least one process state based on the mechanical power (P mech ), the composition of the educts (m a , m f ) and product, and stoichiometric relationships of educts and product; and measuring temperatures of the educts and product, and determining enthalpies for the educts and product using enthalpy functions associated with their respective compositions, wherein determining the enthalpies for educts and product is based on their respective temperatures, and wherein determining the value of the at least one process state is based on the enthalpies.