To rapidly warm a solid electrolytic material up to a temperature at which admittance denoting the temperature condition thereof reaches a target admittance and to smoothly maintain the target admittance, in the case of a gas sensor equipped with a heater for warming the solid electrolytic material of a cell up to an activation temperature.
Power feed control for a heater 13 by a microcomputer 28 is performed so that heating is made at one dash with a fixed duty such as 100% up to a prescribed value lower than the target admittance, and PI control is put into execution when the target admittance is approached. As for the PI control, high gain is employed until reaching the target admittance to avoid a drop in admittance. When the target admittance is reached, low gain is employed to enhance convergence to the target admittance.
KUROKAWA HIDEKAZU
HANEDA SATOSHI
