In this article is shown a path to define constants as well as input and output variables when elaborating a parametric model of an internal combustion engine by triggered ignition. There are discussed the different critical factors that should be considered when determining the constants and variables, this includes the engine operating conditions, the properties of the fuel and the emissions generated. In addition, there is also described the methods used to measure and validate these constants, variables, graphic methods and the different type of model founded. It concludes with the revision of the practical applications of the parametric model including its performance and concentration of the CO2 emissions to the environment.
