Patent ID: 6156176
Filing Date: 2000-12-05
Classification: G01N

Abstract:
An air fuel ratio sensor for detecting an air fuel ratio of measurement gas using reference gas introduced into a reference gas chamber formed therein, the air fuel ratio sensor comprising:a first solid electrolyte body portion having oxygen ion conductivity, the first solid electrolyte body portion having a first surface exposed to the measurement gas and a second surface exposed to the reference gas in the reference gas chamber;a second solid electrolyte body portion having oxygen ion conductivity, the second solid electrolyte body portion having a first surface exposed to a gas outside the reference gas chamber and a second surface exposed to the reference gas in the reference gas chamber;a measurement cell provided on the first solid electrolyte body portion for detecting the air fuel ratio in the measurement gas, the measurement cell having a measurement electrode disposed on the first surface of the first solid electrolyte body portion and a reference electrode disposed on the second surface of the first solid electrolyte body portion, the measurement electrode and the reference electrode facing one another with the first solid electrolyte body portion interposed therebetween;an oxygen pump cell provided on the second solid electrolyte body portion and having a first pump electrode disposed on the first surface of the second solid electrolyte body portion and a second pump electrode disposed on the second surface of the second solid electrolyte body portion, the first and second pump electrodes facing one another with the second solid electrolyte body portion interposed therebetween for introducing oxygen gas from said gas outside the reference gas chamber into the reference gas chamber when a voltage is applied between the first and second pump electrodes; anda heating member having first and second lead portions respectively electrically connected to the first and second pump electrodes.