| 摘要 |
PURPOSE:To prevent erroneous decision of failure in operation of an acceleration sensor owing to overlap of a fluctuation component based on oscillation of a car body and the generation of noise with an output component based on a diagnosis pulse signal. CONSTITUTION:A collision detecting device 14 comprises a piezoelectric type acceleration sensor 10, and a collision deciding device 12 to decide that collision of a vehicle occurs when an output from an acceleration sensor exceeds a reference value. The failure detecting device 24 of the collision detecting device comprises a diagnosis pulse signal generating device 16 to input a diagnosis pulse to an acceleration sensor, a failure deciding device 18 to decide that the acceleration sensor is failed in operation when the output of the acceleration sensor when a diagnosis pulse is inputted is below a set value, a computing device 20 to compute the magnitude of a fluctuation or the coefficient of a fluctuation in the output of the acceleration sensor in a given time before a diagnosis pulse is inputted or the magnitude of the coefficient of a fluctuation, and a correction device 22 to reduce a set value for correction when the magnitude of a computed fluctuation or that of the computed coefficient of a fluctuation exceeds a given value. |
