Device and method for gas analysis

摘要

The emission gases from an engine exhaust are collected through an inlet of a dilution tunnel constituted by an elongated hollow pipe. The inlet is separated from the exhaust pipe in such a way that atmospheric air is also taken in. The atmospheric air and the emissions are thoroughly mixed in the tunnel by means of a screen in the tunnel. A probe in the tunnel guides a part of the mixture to gas analysers. Before analysis, the mixture can be condensed, filtered or otherwise treated. The analysis determines a CO/CO2 ratio which is used to determine the air/fuel ratio in the engine on the basis of the characteristics of the fuel. The air/fuel mixture of the engine is then set so as to obtain the desired power.