HEATER CONTROL DEVICE OF GAS CONCENTRATION SENSOR

PROBLEM TO BE SOLVED: To control suitably current application to a heater, and to thereby protect a sensor element. SOLUTION: An A/F sensor 21 is disposed on an exhaust pipe 11 of an engine 10. The heater for changing the element into the activated state is attached to the sensor element constituting the A/F sensor 21. An ECU 30 controls a supply power to the heater by a prescribed power at the temperature rising time in a temperature rising process of the sensor element. A change of an exhaust gas flow rate flowing in the exhaust pipe is estimated, and when the exhaust gas flow rate is estimated to be increased, the heater supply power is temporarily suppressed on the assumption that a sensor cooling condition is established. COPYRIGHT: (C)2005,JPO&NCIPI