GF07.61-P-3025BK O2 Sensor Heater - Function

GF07.61-P-3025BK O2 Sensor Heater - Function







The purpose of the O2 sensor heater is to rapidly heat up the O2 sensors to their operating temperature while preventing damage to the sensor ceramic through heat control.

The O2 sensor heater is actuated and pulsed by the ME control unit by means of a ground signal. Each sensor heater has its own, short circuit proof output stage in the engine control unit with diagnosis. As a protection for the ceramic, the sensor temperature upstream of TWC is limited to approx. 350 °C in the condensation phase after cold start. The temperature is then controlled to approx. 700 °C after this. The internal resistance of the Nernst cells (which generate the lambda sensor signal) is evaluated.

Different values apply to the O2 sensor heaters downstream of TWC.

Voltage supply to the O2 sensor heater is fused over the engine circuit 87 relay.

The power absorption capacity of the O2 sensor heater as of an exhaust gas temperature of 350 °C is less than 7 W. The current in the cold state is increased by the factor 4.