HEATED OXYGEN SENSOR CONSTRUCTION/OPERATION [AJ (3.0L Duratec)]
BUE014018860N04
• Installed in front of the catalytic converter.
• The built-in heater promotes activation of the heated oxygen sensor at engine start (when exhaust gas is at low temperature).
• A zirconium element is used on the sensor. When there is a difference between the oxygen concentration on either side of the element, electromotive force is generated by the movement of oxygen ions (atmospheric air on the inner side of the zirconium element, exhaust gas on the outer side). The electromotive force changes significantly at the boundary of the stoichiometric air/fuel ratio (A/ F=14.7). The PCM inputs the voltage generated from the HO2S directly, and increases or decreases the fuel injection amount by the fuel injection control so that it is close to the stoichiometric air/fuel ratio.
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1
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High
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2
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Output voltage
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3
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Low
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4
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Rich
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5
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Air/fuel ratio
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6
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Lean
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• When the temperature of the zirconium element is low, electromotive force is not generated so the element is heated by a built-in heater, promoting the oxygen sensor activation. Due to this, the sensor is efficiently activated even immediately after cold-engine start, and a stable sensor output can be obtained.
