| 摘要 |
<p>Two identical pick-ups (1, 2) are positioned in the flow of exhaust gas and the ambient air respectively, both at the same temp. The sum (13) of the currents detected at the two pick-ups is compared both with a voltage proportional to the high tension supplied, and with a constant voltage (16) as well as with a constant current (16a). The high tension supply to these pickups is controlled as a function of the difference between these comparisons. The currents provided by the pick-ups are compared (10) and the result of comparison is used to determine the percentage of oxygen in the gas. The two pick-ups are arranged for one to carry the exhaust gas from an internal combustion engine, and the other to carry air at the same temperature. The processing circuitry determines the concentration of oxygen in the exhaust gas by comparison with the ambient air.</p> |
