Patent ID: 6131438
Filing Date: 2000-10-17
Classification: G01N

Abstract:
A method of operating a calorimetric gas sensor by modulating its operating temperature, said method consisting of the steps of:providing a calorimetric gas sensor having a sensing element and a reference element;allowing diffusion of a gas including combustibles to react with the sensing element;heating the sensing element and the reference element of the calorimetric gas sensor to a first temperature between a predetermined minimum temperature and a light-off temperature of the sensing element defined as the temperature at which the conversion rate of combustibles reacting with oxygen on the calorimetric gas sensor is half of the maximum value;modulating the heating of the sensing element and reference element to vary the temperature of the calorimetric gas sensor continuously between a second temperature above the light-off temperature and the first temperature to produce an alternating current (AC) sensor output; andmeasuring the AC sensor output at the frequency of modulation.