Gas sensing apparatus and method

A gas sensing method for sensing gases using a gas sensing device having a sensing layer that has a voltage supplied thereto in which the sensing layer is self-heated by the supplied voltage and that reacts with particular gases of interest and a current detection circuit for detecting the current level flowing through the sensing layer, the method comprising the steps of:

• storing current-voltage reference data corresponding to measured values of current flowing through the sensing layer for a plurality of voltages for each of a plurality of gases at different densities for the plurality of gases in an ambient atmosphere;
• applying a variable voltage to the self-heated sensing layer and detecting the resultant currents flowing through the sensing layer;
• referencing the stored current-voltage reference data in accordance with the measured voltage supplied to the sensing layer and the corresponding detected current level flowing through the sensing layer for the supplied voltage;
• and
• identifying the kind and density of the particular gases of interest by identifying the kind and density of gas corresponding to the current/voltage reference data that most closely matches the applied voltage and resultant current levels.