Development of an on-board visual display for early knock detection in SI engine

Abstract

The main purpose of this project is to develop an on-board visual display for early knock detection in SI car engines. The system consists of a low-cost piezoelectric accelerometer and two signal processing boards with wireless data transmission capability. One board is placed on the engine side and other board is used to visualise engine vibration on the user end. This kind of visualization is useful for a maintenance person to detect knock in early stages. The signal processing board contains dsPIC microcontroller that processes the vibration data acquired by a low-cost ADXL accelerometer. The board is programmed with Fast Fourier Transform (FFT) algorithm to perform the frequency calculations in order to detect knock in the car engine. Once the knock calculation is completed by the dsPIC microcontroller, it transmits the data to the main board on the user’s end through X-Bee wireless protocol. Finally, the FFT spectrum is displayed on a Graphic Liquid Crystal Display (GLCD) and hence the possible frequency of interest on which knock occurs. This kind of device helps the car user and maintenance person to be aware of the early knock symptoms.