• 대한기계학회논문집B
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• 제29권12호
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• pp.1335-1343
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• 2005

The calibration technique of Time Resolved Laser Induced Incandescence was investigated both experimentally and numerically by using standard-sized carbon black particles for the instantaneous soot measurement at exhaust tail pipe in engine. The carbon black particles (19nm, 25nm, 45nm and 58nm) used in this study are similar, though not identical, to soot particle generated from flame not only in morphology but also in micro-structure. The amount of soot loading in flow was controled by a diluted gas (nitrogen) and was measured by the gravimetric method at exhaust pipe in calibrator. The successful calibrations of primary particle size and soot mass fraction were carried out at the range from 19nm to 58nm and from $0.25mg/m^3$ to $37mg/m^3$ respectively. And based on these results the numerical simulation of LII signal was tuned and the effect of an exhaust temperature variation on the decay rate of LII signal was corrected.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.78-85
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• 2007

Recently, diesel vehicles have been increased and their emission standards have been getting strict. The emission of diesel vehicles contains numerous dangerous compounds, especially particulate matters cause a serious environmental pollutant and affect to human health seriously. Thousands of studies have already reported that particulate matters are associated with respiratory and cardiovascular diseases, and death. Due to these, it is necessary to measure the soot concentration and soot particle size in laboratory flames or practical engines to recognize the soot formation, and develop the control strategies for soot emission. In this study, the characteristics of exhausted soot particle size and volume fraction from 2.0L CRDI diesel engine have been investigated as varying engine speed and load. Laser induced incandescence has been used to measure soot concentration. Time-resolved laser induced incandescence has been used to determine soot particle size in the engine. The soot volume fraction is increased as increasing engine load but soot volume fraction is decreased as increasing engine speed. The primary particle size is distributed about $35nm{\sim}60nm$ at each experimental conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2002년도 제22회 학술발표회 초록집
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• pp.202-202
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• 2002

• 한국분무공학회지
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• 제5권1호
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• pp.23-29
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• 2000

Recently the laser sheet technique has been developed to improve our limited understanding of the in-cylinder diesel combustion. The technique is capable of high temporal and spatial resolution, so that it is proved to be an adequate combustion diagnostics to find out exhaust emission formation. The optical signals of LIS(Laser Induced Scattering) and LII(Laser Induced Incandescence) images show informations for soot concentration within the optically accessible diesel engine. The LIS and LII signal images of soot concentration provide new insight into where and when soot occurs in a diesel engine.

• Journal of Mechanical Science and Technology
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• 제15권9호
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• pp.1311-1318
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• 2001

It is necessary to diagnose accurately the characteristics of soot formation and oxidation in a diesel engine. Whereas past measurement techniques for soot concentration give limited information for soot, laser-based two-dimensional imaging diagnostics have a potential to provide temporally and spatially superior resolved measurements of the soot distribution. The technique using laser sheet beam has been applied to an optically accessible diesel engine for the quantitative measurement of soot. The results provided the information for reduction of soot from the diesel engine. Both LIS (Laser Induced Scattering) and LII (Laser Induced Incandescence) techniques were used simultaneously in this study. The images of LIS and LII showed the quantitative distribution of the soot concentration in the diesel engine. In this study, several results were obtained by the simultaneous measurements of LIS and LII technique. The diameter and number density of soot in combustion chamber of the test engine were obtained from ATDC 20 degree to 110 degree. The soot diameter increased about 37% between ATDC 20 degree and 110 degree. The number density of soot, however, decreased significantly between ATDC 40 degree and 70 degree.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.157-163
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• 2006

A new technique utilizing LII signal for the measurement of flow velocities of laminar diffusion flames has been investigated. Soot particles in ethylene diffusion flames are heated by a modulated Ar-ion laser beam. LII signals and their phase angles are measured using a lock-in amplifier at the different flame heights and the axial flow velocity are obtained from the measured phase angle delay. The measured velocities are similar to those from LDV measurements under the same operating conditions. The effects of laser power, LII signal wavelength, and modulation frequency are not sensitive to the velocity measurement. However, the choice of an optical chopper blade type could affect the measurement result. The use of a 6/5 chopper blade showed the better result that is possibly due to the square shape of modulated laser beam. This study successfully demonstrated that axial flow velocities of laminar diffusion flames can be measured by a new technique utilizing LII signal, which does not need particle seeding unlikely to LDV or PIV techniques.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.60-61
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• 2002

Laser-induced incandescence (LII) 측정법은 조사된 레이저에 의하여 입자가 가열됨에 따라서, 그 온도에 상응하는 흑체복사의 시간적 감소추이가 입자의 크기에 따라서 달리 나타나는 것을 이용하여 입자의 크기를 측정하는 방법이다. LII 감쇄법은 레이저에 의하여 가열된 입자의 에너지 균형 상관식에서 입자의 크기가 클수록 신호의 감쇄속도가 느리고, LII 신호의 감쇄비가 실험적으로 입자의 크기에 비례한다는 사실을 이용하여 연소진단에 응용되어 왔다. (중략)

• 한국분무공학회지
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• 제6권2호
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• pp.22-28
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• 2001

Recently, many researches have been performed to improve the combustion and emission in a D.I.Diesel engine. Especially reduction of the soot formation in the combustion chamber is the essential to acquire the improvement of the emission performance. This emission of the diesel combustion is effected by the characteristics of air-fuel mixing. Therefore, the optical measurement technique such as LII and LIS were established in order to visualize the distribution of the soot and analyze the particle including spray in the combustion chamber. In this study, we developed the algorithm for calculating relative diameter and density of particle and applied this method to measure stimultaneously the distribution of soot and spray in a D.I. diesel engine. From this experiment we found that the soot is existed in the rich region of spray and generated caused by incapable air fuel mixture.

• 한국가시화정보학회지
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• 제2권1호
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• pp.12-17
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• 2004

The physical characteristics of soot near the soot inception point were investigated with various measurements. In-situ measurements of particle size and volume fraction were introduced based on time resolved laser-induced incandescence (TIRE-LII) and laser-induced ion mobility (LIIM). The one has more convenience and accuracy than conventional LII technique and the other works best for particle sizes of a few nanometers at high concentrations in a uniform concentration field. A complementary ex-situ measurement of particle size is nano differential mobility analyzer (Nano-DMA), which recently developed for measuring particle sizes between 2nm and 100nm and provides high-resolution size information for early soot. Particles will be also collected on transmission electron microscope (TEM) grids using rapid thermophoretic sampling and analyzed for morphology. These measurements will allow fresh and original insight into the characterizing soot inception process. The measured physical properties of incipient soot will clarify the controlling growth mechanism combined with chemical ones, and the dominant mechanism for soot modeling can be deduced from the information.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.95-102
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• 2006

Recently particulate matter(PM) emission regulations are becoming more strict for diesel engines. There is increasing interest for measuring not only concentration but also size of the particles. Laser-induced incandescence (LII) has emerged as a promising technique for measuring particle volume fraction and size. In this study, the Simple Time Resolved-LII method was applied to exhaust of Ethylene diffusion flame and diesel engine exhaust for measuring soot and PM size. The particle size data from LII technique were calibrated using Field Emission Scanning Electron Microscope(FE-SEM) and Transmission Electron Microscope(TEM) photographs. In diesel engine experiments for particle size measurement, results from LII measurement are in a good agreement with those from TEM photograph, and difference between two measurements was less than 16%.