B-like Oxygen Sensor
Oxygen sensors are require due to the increasingly tough exhaust emissions and go hand-in-hand with the catalytic converters. One oxygen sensor is used in the exhaust branch right before the catalytic converter. Sometimes a second oxygen sensor is placed in the exhaust system after the catalytic converter of a spark-ignition engine to permit opti- mum performance of the three-way catalytic converters.
The information obtained from the sensors indicates how complete the combustion process is in the combustion cham-ber. The optimum readings are obtained when the air to fuel ratio is 14.7 to one. The stoichiometric air/fuel ratio is the mass of 14.7 kg of air to 1 kg of gasoline theoretically necessary for complete combustion. The excess air factor or air ratio indicates the deviation of the actual air/fuel ratio from the theoretically required ratio.