| 摘要 |
An engine air/fuel ratio sensing device for measuring the oxygen partial pressure or concentration in the exhaust gas of an engine. The device has a sensor and a control circuit coupled to each other. The sensor consists of an electrolyte oxygen pump cell and an electrolyte oxygen sensor cell, both cells having a gap portion therebetween. The control circuit provides a pumping current through a current limiting resistor to the pump cell and measures two terminal voltages across the current limiting resistor to derive the actual pump current and the internal resistance of the pump cell, the latter being converted into the actual temperature to which the sensor is exposed. The actual pump current and the actual temperature are used to correct the actual pump current to a proper pump current dependent on the temperature, in accordance with a predetermined equation. |
