"Method for estimating the filling of a cylinder in an internal combustion engine"

Method for estimating the filling of a cylinder (2) in an internal combustion engine (1) provided with cam stroke variation system (10). A theoretical induction efficiency ( eta thr) which the cylinder (2) would have if it operated with an optimal induction/exhaust timing value (VVT) is estimated; said theoretical induction efficiency ( eta thr) is derated by a correction factor (KVVT) depending on the induction/exhaust timing value (VVT) actually used to estimate the induction efficiency ( eta asp), which is a standardised measurement of the filling of the cylinder (2).