The Study Of Vehicle Knock Sensor And Its Testing System

As energy issues become increasingly prominent, many engines by increasing fuelcompression ratio to improve fuel efficiency, but it also produces a negative phenomenon,that is engine knock, engine knock is an abnormal combustion which will cause the engineto work rude, increase fuel consumption, so how to reduce knock become a very importantproblem in the engine combustion process. Knock sensor currently widely used to detectengine knock, and then transmit the output signal of the knock sensor to the ECU.This paper begins with knock sensor theoretical analysis, the first analysis atheoretical model of the knock sensor, Using Matlab software to simulate the impact factorof the knock sensor, imitation of each factor how to change the sensitivity of the knocksensor, using theoretical simulation analysis to guide the actual design of the sensor.Secondly, based on the measuring parameter of the knock sensor, we design theknock sensor testing system, the testing system using virtual instrument software Labviewcombined with data acquisition card to achieve real-time acquisition of the knock sensoroutput signal.Finally, combining the knock sensor testing system we designed, verified the Delphistandard sensor、knock sensor we designed and the testing system stability. Do majorparameters changes and compare the different sensitivity of the sensor, ultimately improveour self-designed sensor, in order to reach Delphi standard.The performance of the knock sensor we designed reached the standard of Delphi,and low cost, to some extent, can replace imported knock sensor, the testing system canalso be widely used in the vibration test.