Exhaust contents affect on sensor voltage
Zirconia signal
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Signal
The signal refers to the voltage relayed to the ECU (Electronic Control Unit) from the oxygen sensor. Different kinds of sensors relay different signals.
A titania style sensor does not generate its own signal or voltage, it receives 5 volt from the ECU and sends back a signal from 1000 ohms resistance (on a rich mixture) to 20,000 ohms resistance, (on a lean mixture) depending on the current air fuel mix.
A zirconia sensor generates its own signal (voltage) and will deliver 0.45 volts when the air fuel ratio is stoichiometric. If the air/fuel ratio is lean (say 18 to 1) the sensor will deliver less than .045 volts (as low as 0.0 volts for straight air) and the ECU will allow more fuel through the fuel injector. If the air fuel ratio is rich (say 12 to 1), the sensor will deliver more than .045 volts (up to 1.1 volts) and the ECU will decrease the fuel through the fuel injectors.
Newer model cars are now coming with Air/Fuel sensors and Wide Band Oxygen Sensors. A Planar air fuel sensor operates like a zirconia sensor and generates its own signal, while the wide band oxygen sensor is similar to a titania style in that it is dependent on a controller or ECU to generate a signal.
The speed at which the sensor can switch between reporting a rich to lean (or lean to rich) signal back to the ECU is called the cross count. The higher the quality of the sensor, the higher or faster the cross count. Bosch sensors have one of the highest cross count in the industry which means your engine will perform at its best. |
