Temperature actuated zeolite in-line adsorber system

Claim 1

An in-line engine exhaust system for a hydrocarbon-containing engine exhaust stream comprising a light-off catalyst, a housing downstream of the light-off catalyst, and a burn-off catalyst downstream of the housing, the burn-off catalyst having a light-off temperature and being capable of converting hydrocarbons to carbon dioxide and water, the housing having an inlet or upstream end, a flow control device located in the upstream end, an outlet or downstream end, and a honeycomb structure having a first and a second region located therein, the first region having disposed therein a molecular sieve structure for adsorbing the hydrocarbons, the molecular sieve structure having a first temperature, the second region located within the first region and comprising an open or free-flow region, the flow control device occupying a first position when the temperature of the molecular sieve is less than a predetermined level and operating to direct substantially all of the exhaust stream to the molecular sieve structure to thereby adsorb the hydrocarbons and thence to the burnoff catalyst, and the flow control device occupying a second position when the molecular sieve temperature is at or above the predetermined level operating to direct a major portion of the exhaust stream to the second region, and a minor portion through the first region and thence to the burn-off catalyst.