Engine exhaust system for reduction of hydrocarbon emissions
AssigneeCorning Incorporated
InventorsJ. Paul Day, Louis S. Socha, Jr.
Life of this patent
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Abstract
An engine exhaust system disclosed which is designed to reduce hydrocarbon emissions caused by the evaporation of fuel from the fuel tank and by the inefficiency of combustion and catalytic conversion during cold engine start-up. This system utilizes molecular sieves, such as high-silica zeolites, which adsorb hydrocarbons evaporating from the fuel tank or emitted during engine start-up, before the catalytic converter has attained an effective operating temperature. This system is designed so that hydrocarbons that would otherwise be emitted to the atmosphere from the fuel tank or by passing through the converter unconverted are held within the system either for combustion in the engine or passage through the converter once it is operating efficiently.
Claims23
An engine exhaust system for reducing evaporative emissions of a hydrocarbon fuel comprising
- an engine;
- a fuel tank, including a vapor space, for storing hydrocarbon fuel for said engine;
- molecular sieve means for adsorbing hydrocarbons evaporating from said fuel, said molecular sieve means being capable of having hydrocarbons desorbed therefrom upon heating to a desorption temperature;
- vapor-conveyance means for providing communication between said molecular sieve means and the vapor space of said fuel tank;
- and
- purge means for conveying a heated purge stream through said molecular sieve means and then conveying at least part of said purge stream back to the engine.
Dependencies are inferred from the claim text.