Infrared absorption device for analysis of exhaust gases from moving vehicles.

An infrared absorption system for real-time measurement of pollutants in exhaust gases From moving vehicles is proposed. The system consists of an infrared source at one side of the road, and a wheel with specific IR filters and a detector at the other side. We have, firstly, simulated the expected exhaust gases concentrations at different inspection conditions. The well-known HITRAN database has been used in order to estimate intensities, signal-to-noise ratio and threshold concentration levels. These results have then been verified by open-path Fourier Transform Infrared (FTIR) spectroradiometry of the exhaust gases from both gasoline and Diesel vehicles. This confirms the feasibility of such a device by using some conventional filters -those of CO, CO2 and NO2 for example- and some ultra-narrow solid state Fabry-Perot filters -that of NO for example-. As the proposed system monitors all kind of oxides and hydrocarbons in exhaust gases the stoichiometry of the combustion or "lambda coefficient" may be also deduced and it is fully appliable for "Ministry Of Transport" Test of Vehicles (MOT or "Technical Inspection of Vehicles" ITV).