AIR FUEL RATIO (A/F) SENSOR CONSTRUCTION/OPERATION


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•  Installed on the exhaust manifold.
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A/F sensor

•  The wide-range air/fuel ratio sensor is a pump cell type sensor, using both the oxygen concentration cell action and oxygen pump cell action, and can detect the oxygen concentration (air/fuel ratio of the air-fuel mixture) in the exhaust gas in all ranges, from lean to rich.
•  A heater is built into the sensor to facilitate the activation of the A/F sensor at engine startup (when the exhaust gas temperature is low).
Operation
•  The wide-range air/fuel ratio sensor converts the oxygen concentration in the exhaust gas into a current value, and sends the value to the PCM.
•  The PCM calculates the λ (lambda) value of the air-fuel mixture based on the received current value.
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Current (mA)
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λ (lambda)
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A/F

•  ( λ (lambda)) = (actual air/fuel ratio)/(stoichiometric air/fuel ratio)