Design Of Automotive Engine Sensor Signal Acquisition And Analog Output System

The improvement of automobile electronization improves the performance of electronic-controlled engine,but also increases the difficulty of troubleshooting electronic-controlled engine,and puts forward higher requirements for the quality of maintenance personnel.In order to train maintenance talents,colleges and universities use the existing electronically controlled engine test bench or teaching board to carry out engine fault reappearance teaching.By controlling the on-off and on-off sensor faults of the switch,this method has the shortage of single types and quantities of fault Settings,and cannot fully demonstrate other faults of the electronically controlled engine.For this reason,this paper designs a set of engine sensor signal acquisition and simulation output system which can improve the sampling flexibility and has the function of arbitrary waveform output.The collected fault signals are input into the Electronic Concrol Unit(ECU)instead of the original sensor signals.In the engine fault reproduction teaching,it is of great significance for students to understand the sensor signal characteristics,to master the engine fault mechanism and fault phenomena,and to improve the ability of students and maintenance personnel to fault judgment and troubleshooting.This paper first introduces the performance requirements and classification methods of the engine sensors,analyzes the working principle of the main sensors,output signal characteristics,fault types and the impact on the engine operation,and then designs the signal acquisition and analog output system of the sensors of the automobile engine.The overall scheme is composed of the upper computer and the lower computer,and the communication between the upper and lower computer USES the USB interface to ensure the reliable data transmission and the transmission of control commands.The lower computer includes a sensor signal acquisition board card and a sensor signal generation board card,both of which are based on the "FPGA+ARM+USB interface" architecture.The sensor signal acquisition board card designs the sensor signal attenuation circuit,the sensor signal ADC conversion circuit and the sensor signal acquisition and data reading and writing control logic circuit.The sensor signal generator board card designs the sensor signal DAC conversion circuit,the sensor signal output conditioning circuit,the PWM pulse width modulation output circuit based on ARM and the sensor signal generation and data read and write control logic circuit.The upper computer software is written by MATLAB software,which is used for the acquisition channel and sampling rate setting of the sensor signal acquisition board card,the reception,display,processing and storage of the sampled data,as well as the output control of the normal signal and fault signal of the sensor when the sensor signal occurs.After experimental verification,the system can collect,display,store and output AC signals of 0V ? 5V,-10 V ? + 10 V,and frequency of DC ? 1MHz.Through PWM pulse width modulation,the frequency range is 1Hz ? 10 k Hz.,The duty cycle is 0.1% ? 99.9% of the PWM wave signal output,to achieve the normal and fault signals of the engine's main sensor collection and analog output.