| 摘要 |
PURPOSE:To prevent the overheating of a heater and to prevent the wire breakdown of the heater, by controlling power to the heater with the temperature of the heater for oxygen concentration sensor being computed. CONSTITUTION:The resistance value of a heater (a) that is enclosed in an oxygen concentration sensor (b), which detects the oxygen concentration in exhaust gas, the number of rotation of an internal combustion engine, and exhaust gas temperature are detected by respective detecting means M1-M3. When the exhaust gas and the heater reach a thermal equilibrium, the initial resistance value of the heater at the absolute zero degree is computed from the exhaust gas temperature, the resistance of the heater and the temperature coefficient of the heater, which is memorized beforehand. The temperature of the heater is computed from the resistance value of the heater, the initial resistance value of the heater and the temperature coefficient. Based on the heater temperature, power supply to the heater is controlled by an operation control means M4. |
