AIR/FUEL RATIO DETECTOR

摘要

An A/F ratio detector capable of accurately and unambiguously detecting the operating A/F ratio of a burner such as an internal combustion engine whether the engine is operating in the fuel-rich region, fuel-lean region or at the theoretical A/F ratio. The detector includes a solid-electrolyte oxygen pump element having a porous electrode formed on both sides of an oxygen-ion-conductive solid electrolyte, and a solid-electrolyte oxygen-concentration-difference-actuated electrochemical cell sensor element disposed to face the pump element with a small gap therebetween and which has two porous electrodes formed on opposite sides of an oxygen-ion-conductive solid electrolyte. An air compartment open to the atmosphere is formed on a side of the electrochemical cell sensor element opposite the small gap. The electromotive force generated by one pair of the porous electrodes on the electrochemical cell sensor element, the pump current flowing through the other pair of porous electrodes on the sensor element, or the pump current flowing through the porous electrodes on the pump element provides an output signal for A/F ratio detection.