Methodand apparatus for determining the influence of different control quantities on the measured values of the rotational speed of an internal combustion engine

摘要

The invention is directed to a method and an apparatus of determining whether the rotational speed of an internal combustion engine is attributable to a corresponding correcting quantity signal from an idle air charge control or whether an overrun condition exists. For this purpose, a variable supplementary signal is superposed on the correcting quantity signal of the idle air charge control. The mean value of this supplementary signal may be preferably zero. Taking the dead time of the internal combustion engine into account, the measured rotational speeds are correlated with the changes in the previously issued correcting quantity signals, and it is determined whether the engine is in the overrun mode of operation or idling. If an overrun condition is detected, an overrun recognition signal may be issued to initiate measures aimed at preventing the internal combustion engine from stalling, for example.