A Laboratory Method for the Simulation of Automobile Exhaust and Studies of Catalyst Poisoning

Abstract

The expected use of catalytic converters on automobiles to meet the legislated automotive emission standards makes desirable a laboratory method that permits realistic testing of these catalysts. Such a method should be versatile enough to simulate a wide range of conditions which are applicable for catalysts designed to oxidize hydrocarbons and carbon monoxide, or to reduce nitric oxide, as the case may be. For this purpose, we have modified a pulse-flame combustor, based on a design by Meguerian. The output of this simulator very closely resembles engine exhaust with respect to composition, space velocity, and contaminants. The durability of a monolithic or pelleted catalyst can be evaluated by long term exposure to the simulated exhaust and by periodic measurement of the catalyst activity as a function of temperature. The apparatus and the range of conditions that can be achieved are described in detail. Poisoning of a Pt catalyst by fuels containing low concentrations of lead was studied with this exhaust simulator and compared with results obtained in engine dynamometer tests; a satisfactory correlation of catalyst deterioration was established.