| The number of vehicle is increasing rapidly with the development of the car industry. It has caused not only serious energy consumption, but also caused serious air pollution. In order to solve energy crisis and environmental pollution problems, it is not enough to limit the number of cars, but the reduction of engine energy consumption and emission are popular research direction in today’s world. The burning question is the key part of the engine study and we need measure and analysis combustion process in the engine.Traditional combustion diagnosis need go through into the cylinder. Due to the closed structure of the engine, the precision of traditional internal combustion engine measurement is not enough so that the internal combustion engine testing technology based on the laser appears. The laser goes through the cylinder of internal combustion engine and the material in cylinder is stimulated by laser. Spectrometer accepts the spectra of the material in cylinder and we can get corresponding physical quantities of material in cylinder through the analysis of spectrum. Laser measurement technology is advance technology whether in the field of internal combustion engine or in other areas and it is important in combustion engine cylinder visualization.We have studied the application of laser spontaneous Raman scattering in the field of internal combustion engine. Gas concentration has been tested using by laser spontaneous Raman scattering technique and the calibration of main material O2, CO2 and N2 in engine cylinder has been completed. To study the gas calibration of laser spontaneous Raman scattering, calibration pool has been designed and Raman scattering optical measurement system has been established. The internal size and optical quartz window of pool are same with the optical engine so that the pool can simulate the internal environment of engine cylinder. Heating system and distribution system of the pool have also been established. Raman scattering optical measurement system is composed of Nd: YAG laser, the laser beam expander device, laser pulse stretcher, laser shrink beam splitter, 45°mirror, the light collector, full mirror, 532 nm filter, spectrometer, ICCD, computer, signal generator, etc.In this paper, we study the spontaneous Raman scattering experiment of pure gas O2, CO2 and N2 in 21℃ and 100℃ under different pressure. We got the Raman spectroscopy of O2, CO2 and N2 and analysis the change of Raman spectrum peak area with the change of gas pressure and concentration. The concentration calibration of O2, CO2, N2 have been completed and its calibration curves have been drawn. Meanwhile, the response factors of O2 and CO2 relative to N2 have been calculated and we have verified the accuracy of calibration results in the mixed gas. In order to reduce the error of the laser spontaneous Raman scattering experiment, the error sources, which are composed of the wastage of Nd: YAG laser and the spectrometer, the cleanliness and technological level of quartz window, ICCD noise, etc, have been analyzed.We can get experimental parameters and preliminary experience for the Raman scattering experiment on the optical engine by Raman scattering gas calibration test in the calibration pool. Therefore, we have developed the optical engine system which consist of optical engine, optical engine electronic control system and the data acquisition system to provide hardware equipment foundation for later Raman scattering experiment on optical engine. |
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