| abstract |
Carbon powder or PM can be mixed continuously and quantitatively in a model gas, and the PM oxidation activity of a catalyst in the model gas can be evaluated with high accuracy. SOLUTION: Powder supply means for continuously supplying carbon powder or PM into a standard gas so as to have a predetermined concentration to form a carbon mixture, and an evaluation gas by mixing the carbon mixture into a model gas And mixing means. Since carbon powder or PM is diluted in two stages, an evaluation gas containing a small amount of carbon powder or PM can be stably prepared with high accuracy. Moreover, compared with the case where it dilutes suddenly to low concentration, aggregation of carbon powder or PM is suppressed, and uniform evaluation gas can be prepared. [Selection] Figure 1 |