| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect failure of a car-speed sensor without an additional sensor by determining that the car-speed sensor fails when a predetermined frequency band component of a steering torque signal is more than a predetermined value and a car-speed signal is 0. SOLUTION: In a control means 15, a steering torque signal 'T' detected by a steering torque sensor 12 is passed through a filter by a filter means 18 so as to eliminate a signal only of a steering torque made of a low-frequency component, and only a frequency band component corresponding to a vibration from the road surface generated during running of a vehicle is sampled. Moreover, a predetermined processing is given so that a frequency sampling signal TE is put out to a determining means 19. The determining means 19 amplifies a car-speed signal 'V' from a car-speed sensor 17 and a frequency sampling signal TE from the filter means 18 to an equal potential, rectifies them and compares the car-speed signal 'V' with the frequency sampling signal TE as potential. It is determined as normal when there are both the input signals at the same time or there are none at the same time, while determined as failure when only one of the input signals exists. |
