- Model VEM-100M - UVDOAS Vehicle Exhaust NOx Optical Bench


Vehicle Exhaust Optical Bench is a gas analysis module based on Ultraviolet Differential Optical Absorption Spectroscopy(UV-DOAS), which is able to directly measure NO and NO2 in vehicle/steamship exhust and calculate NOx, without converters.

Vehicle emission NOX analysis bench is a new developed product based on UV-DOAS platform, which is able to simultaneously measure two gas components (NO and NO2)  in vehicle exhaust. It can be widely applied in fields of vehicle exhaust emission detection, road check & spot check of Environment Ministry and Transport Ministry, quick test on exhaust purification device, education & research unit, vehicle exhaust research, automobile manufacture industry, vehicle maintenance industry and etc.

Compared with other detection methods (electrochemistry and NDIR), the adopted technology can realize simultaneous and direct measurement of NO and NO2 with advantages of fast response time, high accuracy, small volume, simple structure and no interference of  background gas  (like moisture). It supports MODBUS protocol and customization.

Based on UV gas analysis technology bench with years of research experience; self-developed core technology and algorithm; strong market competitiveness

Fast response speed, solve NO2 absorption problem, T90≤ 3.5s (NO2 index),T95≤ 4.5s

Without interference of substances like H2O, dust, HC and CO2

Measure NO and NO2 simultaneously and directly, solve the problem that conversion efficiency of conventional converter will gradually decrease over time

Adopting UV-DOAS technology, the optical bench is composed by light source, gas chamber, optical fiber and spectrograph (including diaphragm,  holographic grating and linear array detector) and etc.

The UV light emitted by light source enters gas chamber via optical window and will be absorbed by measured gas; it gathers by lens and couples into optical fiber; enters spectrograph for light splitting and photovoltaic conversion to obtain gas absorption spectrum. The related gas component concentration can be calculated by analyzing the spectrum.

Range: NO 0-4000ppm, NO2 0-1000 ppm

Relative linearity error:≤ ±4%/≤±25ppm

Repeatability: ≤2%


Zero drift:≤ ±2%F.S/24h

Span drift:≤ ±2%F.S/24h

Response time:T90≤3.5s, T10≤3.5s

Anti-interference requirement:NO NO2≤±1%

Gas flow:2±0.1L/min

Supply voltage:220VAC,55W

Interface:RS232, adopt Modbus protocol