Air-Fuel Ratio Sensor for Rich, Stoichiometric and Lean Ranges

Abstract

<div class="htmlview paragraph">This paper describes the sensing principle of a new air-fuel ratio sensor, which has the ability to detect air-fuel ratios in rich, stoichiometric and lean ranges. The sensing part is composed of a gas diffusion layer and a zirconia solid electrolyte with a pair of electrodes which function as an anode and a cathode. The anode and the cathode electrodes are exposed to the atmosphere and the exhaust gas, respectively.</div> <div class="htmlview paragraph">To obtain the bidirectional pumping current between the two electrodes, the potential of the cathode is held to a constant value higher than the electronic circuit ground. The electromotive force induced between the two electrodes is forcibly controlled to a constant value by the electronic circuit. In this composition, three ranges of air-fuel ratio can be detected by the amount of pumping current.</div>