US 5,960,777 A · Combustion engine air supply system

Abstract

A novel method of operating an internal combustion engine employs a selectively gas permeable membrane to provide either oxygen or nitrogen enriched air feed to beneficially affect engine performance. By feeding enriched air from a membrane unit such performance parameters as reduced NOx emissions, lean burn limit, engine power, and reduced cold start emissions can be enhanced relative to feeding ambient air. The selectively gas permeable membrane unit further includes a nonporous membrane (i) having an oxygen/nitrogen selectivity of at least 1.4 and a permeability to oxygen of at least 50 barrers; (ii) formed from an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole; and (iii) being at a temperature below the glass transition temperature of the amorphous copolymer. A cylindrical module having many substantially parallel aligned small diameter hollow fiber membrane structures is ideally suited for carrying out the novel method. The apparatus can be configured to furnish only one of permeate fraction, oxygen enriched air or retentate fraction, nitrogen enriched air. Additionally, the apparatus can be configured to switch between oxygen and nitrogen enrichment modes.

Claims29

Dependent claims

A method of operating an engine energized by internal combustion of a mixture of fuel and combustion air that comprises the steps of:

(A) separating air into an oxygen enriched fraction and nitrogen enriched fraction with a selectively gas permeable membrane unit;
and
(B) feeding enriched air selected from the group consisting of the oxygen enriched fraction and the nitrogen enriched fraction to the engine,
wherein said mixture is free of ambient atmospheric air, and;
wherein the selectively gas permeable membrane unit includes a nonporous membrane (i) having an oxygen/nitrogen selectivity of at least 1.4 and a permeability to oxygen of at least 50 barrers;
(ii) formed from an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole;
and (iii) being at a temperature below the glass transition temperature of the amorphous copolymer.

4 more elements

An apparatus to feed enriched air to an engine energized by internal combustion of a mixture of fuel and combustion air, the apparatus comprising:

(a) a selectively gas permeable membrane unit including
a casing;
and
a nonporous membrane within the casing, wherein the membrane (i) has an oxygen/nitrogen selectivity of at least 1.4, and a permeability to oxygen of at least 50 barrers;
(ii) is formed from an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole;
and iii) is at a temperature below the glass transition temperature of the amorphous copolymer;
a retentate cavity within the casing on one side of the membrane, the retentate cavity being a source of a retentate stream flow of nitrogen enriched air produced by selective permeation through the membrane of oxygen from a feed stream flow of ambient air into the retentate cavity;
and
a permeate cavity within the casing on the opposite side of the membrane, the permeate cavity being a source of a permeate stream flow of oxygen enriched air;
wherein the ratio of the permeate stream flow to the feed stream flow defines a stage cut;
and
(b) pressure modification means for creating a negative pressure gradient across the membrane from a retentate cavity pressure to a permeate cavity pressure;
and
(c) a feed selection valve adapted to direct either said oxygen enriched air or said nitrogen enriched air to the engine,
the apparatus being operative to provide said mixture free of ambient atmospheric air.

12 more elements

Dependencies are inferred from the claim text.

Combustion engine air supply system

Life of this patent

Combustion engine air supply system

Life of this patent

Abstract

Claims29