Vehicle speed detector

Abstract

Abstract PURPOSE:To enable the prevention of malfunctioning by interrupt the vehicle speed signal below the set vehicle speed while the high speed signal continuing no longer than the set time will not be judged to be normal to eliminate the transmission of any abnormal high speed signal generated at the very low speed. CONSTITUTION:As the vehicle speed drops below the set value and the voltage C of a vehicle speed detection capacitor 18 exceeds the set value V1, the output D of a comparator 17 moves to the level L causing a timer capacitor 19 to discharge to the initial value. As the voltage E will not reach the set value V2, the output F of the comparator 21 maintains the level L to close a gate, blocking the passage of the vehicle speed signal. Below the set vehicle speed, when the vehicle speed signal contains a high frequency signal corresponding to a high speed due to abnormal operation of a lead switch 6 or the like, the output D will not reset the capacitor 19 at each cycle as the cycle during the period is too short for the voltage C to reach the voltage V1. Thus, the capacitor 19 fails to reach the voltage V2 up to the set time from the start of charging and thus, the signal equivalent to a high speed can be interrupted during the period.

Inventors

• 👤 Shigeaki Hirano
• 👤 平野　重明

Bibliographic Details