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Gas Sensors for Automotive Applications
Published June 29, 1995 by Associazione Tecnica Dell'Automobile in Italy
Event: Advanced Measurement Techniques and Sensory Systems for Automotive Applications: Accuracy and Reliability
In the framework of this paper, we propose to develop devices for the selective detection of carbon monoxide and oxides of nitrogen. The applications most immediately envisaged relate to air quality in the passenger compartment of motor vehicles and measurement of gas emissions upstream and downstream of the catalytic converter.
Semi-conductor type gas sensors, used at present for this kind of application, have the disadvantage that they react to CO and NOx in such a way that the combined effects of these two gases cancel each other out and render any control system totally ineffective.
In contrast to those sensors which exploit the variations in electrical conductance induced by a gas, the devices developed in the framework of this study function on the basis of an original electrochemical principle. These sensors are constructed using a solid electrolyte: beta alumina.
The electric cell effect observed in the presence of CO and NOx, which are the gases chiefly responsible for pollution by motor vehicles (both petrol and diesel driven), are sufficiently different and unusual to be able to provide selective information about these two component gases.