DEVICE FOR SELF-DETECTING SPEED OF VEHICLE USING PIEZOELECTRIC ELEMENT AND DETECTION METHOD THEREFOR

摘要

The present invention relates to a device for self-detecting the speed of a vehicle, which self-detects the speed of a vehicle using a piezoelectric element, and analyzes and processes a detected signal so as to measure the speed of the vehicle, and a detection method therefor, the device comprising: a bracket which is fixedly mounted on the surface of a vehicle body so as to transmit vibration generated when a vehicle engine is driven; a piezoelectric element which is fixedly coupled to the bracket to convert the vibration transmitted through the bracket into a voltage signal so as to output the voltage signal; a low-pass frequency filter for removing a high frequency and noise from the voltage signal of the piezoelectric element and allowing a low frequency to pass therethrough; a gear shift ratio input unit for inputting a gear shift ratio for comparing the number of revolutions (RPM) of the wheel with the number of revolutions according to a gear shift of the vehicle; and a speed measuring CPU for converting the number of revolutions input by the gear shift ratio input unit and the low frequency input by the low-pass frequency filter into the speed of the vehicle according to the gear shift, so as to output the same. The present invention enables a device for self-detecting the speed of a vehicle to be installed at a desired position on a vehicle body without deforming or disassembling the vehicle, can lower the manufacturing cost of designing and manufacturing a circuit comprising a bracket, a piezoelectric element, a low-pass frequency filter, and a speed measuring CPU, can be easily applied to various devices using speed information of the vehicle, and improves the accuracy and reliability of a detection device.