Direct sampling of engine emissions for instantaneous analysis.

摘要

A method and associated apparatus for on-line gas analysis of a multicomponent gas emission flow, and comprising: continuously withdrawing and regulating the pressure of a first sample flow from the emission flow, continuously withdrawing a second sample flow from the first sample flow by means (10), the second flow sample being diluted with mass controlled amounts of diluent (N2 or air) to lower the dew point of the gas sample to below room temperature; controlling the absolute pressure of the diluted sample to the range of 920-950 mbar by pressure controlling means (15) ; frequently periodically analyzing the diluted sample flow, controlled as to pressure, by fourier-transform infrared spectrometric device (16) to render a concentration measurement for each desired gas species; and correcting each concentration measurement for dilution to derive an undiluted concentration measurement representative of the actual exhaust gas, said correction being accomplished means (17) by measuring the actual air/fuel ratio of the gas emission flow to provide a theoretical carbon concentration in the undiluted exhaust gas and thereafter ratioing the theoretical total carbon concentration to the measured carbon concentration in the sample to provide the needed correction factor.