2.1. Internal Combustion Engine. The mean-value model of an engine describes the engine behavior in a cycle averaged sense. Though it does not contain individual cylinder transient dynamics, the average of engine dynamics over several cycles provides adequate low-frequency dynamic information and it is suitable for many control problems.
Figure 2 depicts a schematic of the mean-value engine model including throttle airflow dynamics, intake manifold
dynamics, fuel film dynamics, engine torque production, and crankshaft dynamics. The time domain mean-value engine model, introduced in the next section, assumes that exhaust gas recirculation (EGR) depends internally on variable valve timing (VVT) and spark advance (SA) remains constant in certain operating conditions. Air fuel ratio (AFR) is also well maintained at stoichiometric.Therefore, this engine model is broken down into four subsystems: electronically controlled throttle body, intake manifold, combustion, and crank shaft Dynamics neglecting fuel dynamics [1]. Intake Manifold. The intake manifold is the plenumbetween the ETB and the engine cylinders. Equation describes a mean-value filling and emptying intake model based on the continuity principle and the ideal gas law[2].The total air that
goes into the cylinders is expressed in an empirical equation