| 摘要 |
A device suitable for use in engine exhaust gas to detect actual air/fuel ratio of air-fuel mixture supplied to the engine. The probe of the device has three electrodes. An oxygen ion conductive solid electrolyte occupies a space between the first and second electrodes, and a porous layer of similar solid electrolyte occupies a space between the second and third electrodes such that exhaust gas directly contacts the first and third electrodes and also contacts the second electrode through the porous solid electrolyte layer. At least one of the first and second electrodes, particularly the second, is made of a catalytic material, and the first and second electrodes serve as output terminals of the probe. Preferably the second and third electrodes are connected to a DC power supply to force a current to flow through the porous solid electrolyte layer to control oxygen partial pressure at the second electrode surface. By selectively determining catalysis of the first and second electrodes and/or the direction or intensity of the current, air/fuel ratios above, below and equal to a stoichiometric ratio can be detected. |
