Electrochemical sensor structure to determine oxygen content in combustion exhaust gases

Abstract

To measure partial oxygen pressure in gases, particularly exhaust gases of automotive-type combustion engines, a solid electrolyte plate of elongated rectangular configuration has at least one electrode pair applied to a single surface thereof, which is exposed to the measuring gas. Preferably, the gap between electrodes is elongated, by forming the electrodes in comb-interdigited form. A thermocouple - temperature sensor can be applied between connecting tracks for the electrodes which extend longitudinally of the electrolyte plate towards the other end thereof, through a sealing mass holding the plate within a housing, the other end forming, simultaneously, a connection terminal for connection to an electric connector or plug. A heating element can be placed on the obverse side of the plate, preferably in the position in the gap between the electrodes. More than one such sensor element may be secured in the same housing, and, for example, two such plates, back to back, with the heating element therebetween, spaced from each other, or as a common block. The sensor may be used for potentiometric and/or polarographic measurement, depending upon cover coatings on the electrodes which control exposure thereof to the gases, catalytic or non-catalytic action of the electrodes (for example being of platinum or gold, respectively) and whether a voltage is applied across the electrode terminals, or the sensor is to operate as an electrochemical cell. Such sensor can be inexpensively made, are suitable for mass production, and flexible with respect to their mode of operation.

Dependencies are inferred from the claim text.