Research On Transient Temperature Measurement Technology Of Diesel Engine Piston

With the continuous development of science and technology and the increasing improvement of people's living standard,higher requirements are put forward for the diesel engines used in various kinds of machinery.Therefore,engine manufacturers in various countries begin to design and produce high-power and lightweight diesel engines.The piston of diesel engine is always subjected to the scouring of high temperature and high pressure gas and has the characteristics of high-speed reciprocating movement,which is easy to cause the damage and fracture of the piston.At present,the piston temperature measurement method is unable to realize the real-time,rapid and accurate measurement of piston temperature under the working condition of diesel engine.Therefore,this paper has done the following work for this difficulty:The heat transfer mode,finite element method of thermal analysis and boundary conditions of thermal analysis are studied.The 3d solid model of piston is built using Creo Parametric software,which is imported into ABQUS software for mesh division.The heat transfer coefficient of the third kind of boundary condition is calculated according to the empirical formula.A kind of thin film sensor which can be used to measure the surface temperature of diesel piston in real time is developed.Through the study of the characteristics of thin film sensor calibration results show that the sensor of the seebeck coefficient is 41.1 uV/?,close to the standard wire type K thermocouple sensor,the sensor response time of 36.7 us,proved that the sensor response of thin film developed rapidly.Analyzed the MAX31855 temperature conversion and cold end compensation principle,designed the hardware circuit of ZigBee core module,data acquisition module and coordinator module,wired the circuit board and added and welded the electronic components to complete the package.Based on the client-server architecture,the monitoring system software for wireless temperature test of diesel piston is designed in C#language in Microsoft Visual Studio software development platform.The performance of the developed thin film sensor and the wireless temperature measuring system is tested,and the voltage signals of different waveforms are sent by the analog signal generator.Through the processing and analysis of the experimental results,it is found that the wireless temperature measuring system can reproduce the voltage signals sent by the transmitting source in real time and accurately,and has good stability and reliability.Using high temperature heating furnace as heat source of the system test,the heat source temperature is set in the range of 100? to 400?,the experiment result,thin film sensors can quickly response to the change of temperature and then sends the voltage signal in real time accurately to the wireless temperature measuring system.