Oxygen Sensor: Description and Operation

This is a self-adjusting engine control system designed to reduce emissions and improve fuel economy. An exhaust gas sensor (oxygen sensor or lambda sond), monitors the oxygen content in the exhaust gases. The exhaust gas measurements are fed into a computerized engine control system, which continuously adjusts the fuel injection system for an optimum air/fuel ratio. This provides the optimum condition for best fuel economy and the elimination of major pollutants by a three-way catalytic converter. Fig. 33.

IMPORTANT!
Small amounts of lead are sufficient to damage the lambda sond. Always use unleaded gasoline.

Fig. 34 LAMBDA SOND (NON HEATED):

LAMBDA SOND (OXYGEN SENSOR)
Measurements are taken by a ceramic sensor in the lambda sond. It produces a small voltage (90 - 100 mV, or 0.9 - 1.0 V) in proportion to the difference between the oxygen content of the exhaust and the oxygen content in the air. The hot exhaust gases heat up the sensor, which begins to operate around 350°C (660°F). The lambda sond is located in the exhaust system upstream of the catalytic converter. Fig. 34.