| Popis: |
Twenty-three hydrocarbons were measured in the exhaust gases from a Volvo passenger car fitted with a 2.3 litre gasoline engine. Measurements were made in the absence of a catalyst, and in the presence of a fresh and an aged three-way catalyst, with particular attention being paid to the emission of benzene and other light aromatic compounds. Loss of catalytic activity through ageing led to an increase in hydrocarbons of 200% from 0.22 to 0.62 g/mille. Loss of activity was most evident for certain compounds notably alkanes (paraffins) although large increases in aromatic emissions were also apparent; catalytic control of ethyne (acetylene) was, however, completely maintained by the aged catalyst. Thus the work reported here demonstrates the selective manner in which a catalyst operates depending upon the chemical structure of hydrocarbons, and how this influences catalyst performance loss via ageing. (A) For the covering abstract of the conference see IRRD 852385. |
