Research Of The Transient Temperature Measurement Technology For The Top Surface Of The Internal Combustion Engine Piston Based On Zigbee

The biggest difficulty for the measurement of piston surface transient temperature in high speed engine is how to transimisson signal to the outside of the cylinder.This paper designed the transient temperature acquation system that was based on Zigbee technology to solve the difficulty.Based on the successful experience of Bluetooth Telemetry,Infrared Telemetry and Storage Measurement,this paper analyzed the advantages and disadvantages of the three measurement methods,and finally determined the Zigbee as the wireless communication mode of the measurement scheme.In this scheme,the thermocouple signal was processed by the cold junction compensation circuit and the signal conditioning circuit and then converted into digital signals by the built-in high-speed AD converter of the microcomputer and stored in the F-RAM memory.Then the temperature data was transmitted by the Zigbee wireless transmission module to the outside of the cylinder.The sampling frequency was increased to 98 kHz by optimizing the hardware circuit and software strategy.The communication protocol between the upper and lower computer was defined to realize the two-way communication between the two,so as to realize the real-time monitoring the working state of the collecting system and controlling it.In addition the new system in the work of stability and reliability,micro-power,etc.have improved.The system had be carried on real machine test on the YUNNEI 4100QB-2 diesel engine.The results showed that under the same torque,the amplitude of temperature fluctuation will decrease with the increase of rotational speed.At the same speed,with the increase of torque,the average temperature outside the duration of combustion and the temperature fluctuation amplitude in the duration of combustion will increase.The experimental data was consistent with the theoretical analysis and the surface transient temperature data measured by the linkage system.It was verified that the system had good reliability and high measurement accuracy.At the same time,the paper also analyzed the problems exposed during the experiment,and put forward some suggestions for improvement.