Device for controlling the air/fuel ratio of an air/fuel mixture fed to an internal combustion engine with catalytic convertor

摘要

A device for controlling the air/fuel ratio of an air/fuel mixture which is fed to an internal combustion engine with catalytic convertor is disclosed, a comparison decision signal of a comparator (20) which compares the air/fuel ratio parameter with a reference level from a reference voltage source (21) being fed to a proportional amplifier (23A). The output of the proportional amplifier (23A) leads to the first input of an adder (25) whose second input is connected to the output of an oscillation signal transmitter (24A). An operating state detector (70) determines the operating state of the internal combustion engine and identifies an output signal on the basis of which the frequency of the oscillation signal generator (24A) is changed. The period of the oscillation signal is shorter here than an inversion half period of the comparison decision signal and the level of the oscillation signal oscillates upwards and downwards around a central level of a signal provided by an integrator (22). A control signal for adjusting the air/fuel mixture is available at the output of the previously mentioned adder (25). <IMAGE>