| 摘要 |
PROBLEM TO BE SOLVED: To obtain an inexpensive apparatus for controlling power conduction to a heater which can eliminate a separate temperature sensor in relation to temperature control for an oxygen sensor mounted to an exhaust pipe for use in controlling the air-fuel ratio of an internal combustion engine, particularly, in relation to power conduction control of a heating heater of the oxygen sensor when the temperature in the exhaust pipe is low at the time of starting the engine and water drops remain in the exhaust pipe, or when it is feared that water drops are generated in the exhaust pipe. SOLUTION: This apparatus for controlling power conduction to a heater has an internal resistance-detecting means 5 for detecting an internal resistance value of an oxygen sensor 2 and a control means 6 which estimates a surface temperature of the oxygen sensor on the basis of the internal resistance value detected by the internal resistance-detecting means, estimates a temperature in an exhaust pipe in the basis of the surface temperature of the oxygen sensor and controls to start the power conduction to the heating heater 3 integrated with the oxygen sensor when the exhaust pipe temperature reaches a predetermined temperature. |
