Oxygen Control For Models With Catalytic Converter

To maintain the optimum degree of efficiency of the catalytic converter, this system aims at achieving the ideal air-fuel mixture (oxygen ratio = 1) for combustion. The heated oxygen sensor is used for this purpose measuring the remaining oxygen in the exhaust gas and transferring this value in the form of signals to the control unit. Here, the mixture composition is correspondingly corrected, if necessary, by changing the injection timing. In the case of failure of an oxygen sensor, control is provided by the DME control unit with a fixed programmed substitute value (0.45 volt). Since a temperature of approximately 300°C is necessary for efficient operation of the oxygen sensor, power is supplied to the two heating resistors in the oxygen sensors via one relay. The relay is activated by the DME control unit I. In models without a catalytic convener, the CO setting can be corrected with a potentiometer (on the HLM).