嵌入式发动机活塞温度测试系统设计

Design of Embedded Piston-temperature Test System for Engine

摘要:

针对发动机活塞温度缺乏有效的测试手段,设计了一种嵌入式活塞温度测试系统。选用K型热电偶作为温度传感器,利用AD590配合2.5V基准电压源输出补偿电势对热电偶冷端温度进行了补偿,通过调节AD8495设定点电压在预设温度下输出上升沿实现了可调触发温度功能。系统在PIC单片机控制下通过内置模数转换器(ADC)采集活塞顶部三个测点的温度数据后,通过CC2530将测试结果发送至上位机接收平台。测试前在高温箱内对系统进行了标定,将实测值与标定值进行了对比并在发动机台架上进行了试验。实测结果表明：系统测量误差为±1℃,在130℃的高温环境下仍能正常工作,具有良好的稳定性和可靠性。

Abstract:

In view of the fact that there is no effective means to measure engine piston temperature, this paper designed one feasible embedded piston-temperature testing system. By selecting K–type thermocouple as temperature sensor and combining AD590 with output compensation voltage of one 2.5V reference voltage source, it further compensated thermocouple cold-end temperature accordingly. In addition, it adjusted AD8495 set-point voltage under present temperature to output rising edge for achieving function of adjustable trigger temperature. After collecting temperature data upon 3 test points on top of piston via embedded Analog-to-digital converter (ADC) under control of PIC single chip, it turns out this system can send all test results to receiving platform of upper computer via CC2530. Before test, the entire system was also calibrated within high-temperature cabinet. After completing a series of comparisons between actually-tested values and calibrated ones, subsequent tests upon engine bench would be conducted. And these actually-tested results show that test accuracy of the system can reach ±1℃. It can normally operate even in high temperature environment up to 130℃, demonstrating better stability and reliability.