Abstract: A method and apparatus in accordance with the invention is described which comprises treating an engine exhaust gas stream containing hydrocarbons and other pollutants. The method of this invention comprises the steps of flowing the exhaust gas stream through a catalytic member comprising a monolith body having a first catalyst zone and a second catalyst zone therein to contact a catalyst in a first catalyst zone to convert at least some of the pollutants in the exhaust gas stream into innocuous products. The exhaust gas stream is then discharged from the catalytic member and flowed through an adsorbent zone to adsorb at least some of the hydrocarbon pollutants with an adsorbent composition. The exhaust gas stream is then discharged from the adsorbent zone and flowed to the second catalyst zone to convert at least some of the pollutants into innocuous products. The exhaust gas stream, so treated, is then discharged to the atmosphere through suitable discharge means.

Abstract: A method and engine control strategy is described that enables improved catalyst performance after having been exposed to severe operating environments. More specifically, rhodium-containing catalysts are reactivated by being subjected to fuel-rich spikes after being exposed to high temperature, excess oxygen conditions which typically arise during programmed fuel-cut engine control strategies. Thus the present invention represents a departure from current control strategies by providing fuel-rich spikes during engine control modes when conventional practice is not to provide rich-fuel spikes.