Air amount measuring system for measuring suction air amount flowing in internal combustion engine

摘要

The system includes a thermal air amount meter (202). A correction unit (206) receives the output signal from the meter (202), to correct the time delay of this signal. A linearising unit (206) receives the output signal of the correction unit, and converts its output signal, based on a previously stored characteristic of the thermal air amount meter in to a signal, the value of which corresponds to an air amount. A digital signal is obtained by A/D conversion of an output signal of the thermal air amount meter, and is subdivided in two circuits. In one circuit a time constant (tau is obtained, and an inverse transformation is carried out, to obtain a fault, in conjunction with an output of the other circuit. The inverse transformed signal is linearised on the basis of the characteristic of the thermal air mount meter, in addition the flow direction is determined.