Comparative studies of photo-acoustic gas analyzers based on tunable CO2 lasers with external and intracavity detector arrangement

Sherstov, I. V.; Vasiliev, V. A.; Karapuzikov, A. I.; Zenov, K. G.

doi:10.1016/j.infrared.2019.103170

Cited by 11 publications

(2 citation statements)

References 39 publications

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“…The pollutants exhausted from motor vehicles encompass harmful gases such as carbon dioxide (CO 2 ), nitrogen oxides (NO x ), carbon monoxide (CO), and volatile organic compounds, as well as particulate matter [7,8]. Currently, the detection technologies for gaseous pollutants are relatively mature and include laser gas analyzers for measuring CO 2 and NO x concentrations [9,10], as well as opacity meters for assessing smoke opacity [11]. However, as the awareness of the hazards associated with particulate emissions has grown, governments and environmental agencies have introduced stricter regulations and standards for motor vehicle emissions, along with heightened testing requirements.…”

Section: Introductionmentioning

confidence: 99%

Calibration and Experimental Study of a Self-Developed Particle-Number Measurement Instrument

Li,

Luo,

Zhang

et al. 2023

Processes

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To accurately evaluate the size and distribution characteristics of the emission particles exhausted from in-use motor vehicle engines, we independently developed a condensation particle counter (CPC) known as BHCPC. It was calibrated by conducting the calibration procedures stated in the International Standard ISO 27981. After calibration, we conducted on-site measurements and offline sampling analysis of soot particles exhausted from different engines at a motor vehicle inspection center. The calibration results show that the detection efficiency is 90% when the particle diameter is 20.6 nm and the startup response time of the instrument is 3.53 s. The experiment results show that the self-developed BHCPC demonstrates good consistency in measuring particle-number concentration (PNC) in motor vehicle exhaust, with significant count fluctuations only occurring when PNC is higher than 25,000 P/cc. Under idle conditions, motor vehicles compliant with China VI emission regulations exhibit markedly lower exhaust emission PNC compared to those adhering to China IV emission regulations. Moreover, the results obtained from the offline electron microscope analysis show that fuel content in particle samples significantly decreases as engine speed increases, and a similar variation was also found in particle size. The micro-characteristics of the particle can give potential support to the combustion diagnostics.

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Section: Introductionmentioning

confidence: 99%

Calibration and Experimental Study of a Self-Developed Particle-Number Measurement Instrument

Li,

Luo,

Zhang

et al. 2023

Processes

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“…Because of the high absorption coefficient of NO 2 and the high optical power of LD, the saturated absorption of NO 2 should be considered . Therefore, the detection of NO 2 is usually accompanied by gas flow. ,, To realize dynamic measurement, differential PA cells (DPACs) are used to reduce the gas flow noise. − …”

mentioning

confidence: 99%

Rapid Photoacoustic Exhaust Gas Analyzer for Simultaneous Measurement of Nitrogen Dioxide and Sulfur Dioxide

Qi,

Zhao,

et al. 2024

Anal. Chem.

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A rapid photoacoustic (PA) exhaust gas analyzer is presented for simultaneous measurements of nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ). A laser diode (LD) emitting at 450 nm and a light-emitting diode (LED) with a peak wavelength of 275 nm operated simultaneously, producing PA signals of NO 2 and SO 2 , respectively. The LD and LED were modulated at different frequencies of 2568 and 2570 Hz, and their emission light beams were transmitted through two resonant tubes in a differential PA cell (DPAC), respectively. A self-made dual-channel digital lock-in amplifier was used to realize the simultaneous detection of dual-frequency PA signals.Cross interference between the PA signals at the two different frequencies was reduced to 0.02% by using a lock-in amplifier. In order to achieve a rapid dynamic measurement, gas sampling was accelerated by an air pump. The use of mufflers and the differential PA detection technique significantly reduced the gas sampling noise. When the gas flow rate was 1000 sccm, the response time of the PA dual-gas analyzer was 8 and 17 s for NO 2 and SO 2 , respectively. The minimum detection limits of NO 2 and SO 2 were 1.7 and 26.1 ppb when the averaging time of the system was 10 s, respectively. Due to the wide spectral bandwidth of the LED, NO 2 produced an interference to the detection of SO 2 . The interference was reduced by the precise detection of NO 2 . Since the radiations of the LD and LED passed through two different PA tubes, the impact of NO 2 photochemical dissociation caused by UV LED luminescence on NO 2 gas detection was negligible. The sharing of the PA cell, the gas lines, and the signal processing modules significantly reduced the size and cost of the PA dual-gas analyzer.

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An Approach to the Development of an Atmospheric Air Monitoring System

Dovgal

Gura

Stepanenko

et al. 2023

Lecture Notes in Networks and Systems

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Comparative studies of photo-acoustic gas analyzers based on tunable CO2 lasers with external and intracavity detector arrangement

Cited by 11 publications

References 39 publications

Calibration and Experimental Study of a Self-Developed Particle-Number Measurement Instrument

Calibration and Experimental Study of a Self-Developed Particle-Number Measurement Instrument

Rapid Photoacoustic Exhaust Gas Analyzer for Simultaneous Measurement of Nitrogen Dioxide and Sulfur Dioxide

An Approach to the Development of an Atmospheric Air Monitoring System

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