| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine breakage of a heater wiring, without requiring additional parts. SOLUTION: There are provided: a detected temperature loading part 43 for loading detected temperatures Ta, Tb and Tc of a sensor element 23, at the start time of the current application and at a predetermined time, after the start of the current application to the heater 24; a calculation part 44 for calculating the temperature gradient, before the current application Tk1 (=Tb-Ta) and a temperature gradient, after the current application Tk2 (Tc-Ta); and a comparison part 45 for comparing both the temperature gradients Tk1, Tk2 to determine the presence of the wire breakage, when the temperature gradient, after the current application Tk2, does not exceed the predetermined value with respect to the temperature gradient, prior to the current application Tk1. A buzzer 32 is provided as a warning means; and the buzzer 32 is sounded, when it is determined that there is wire breakage. COPYRIGHT: (C)2009,JPO&INPIT
|
