Mehrstoffmaschinensteuerung mit Verriegelung eines Treibstoffsteuerparameters

摘要

A fuel control for an engine using a liquid mixture of two fuels such as gasoline and methanol derives a fuel control parameter such as a desired fuel/air ratio from the output of a fuel composition sensor in a first mode of engine operation. The value of the fuel control parameter at the end of the first mode of engine operation is locked for use throughout a second mode of engine operation including closed loop control in response to an air/fuel ratio sensor, as long as the fuel composition does not change more than a predetermined amount during the second mode. The stable operation of the fuel control in the second mode is thus protected from instabilities introduced by small insignificant fluctuations in the fuel composition signal. In an engine with adaptive learning control the adaptive learning control mode is reserved for particularly stable modes of engine operation including closed loop stoichiometric control and thus serves well as the second mode of engine operation.