Physical characteristic i.e. concentration, determination method for oxygen in exhaust gas from e.g. petrol engine, in motor vehicle, involves determining physical characteristic of gas when change of voltage is detected

摘要

The method involves loading a pump cell (154) in a sensor element (110) with a pump voltage at a time point and operating in a pumping operation. The pumping electricity flowing through the cell is measured. The determination is made whether a characteristic change arises in a Nernst counter voltage applied between an inner electrode (136) i.e. pure oxygen electrode, and an outer electrode (138) i.e. oxygen electrode, in the cell. The physical characteristic of gas is determined from the time period of occurrence of the characteristic change after the time, when change of voltage is detected. An independent claim is also included for a gas physical characteristic determining device comprising a sensor element.