Method for Reducing NOx Emissions from Ethanol-Blended Diesel Fuels

Abstract

A method to reduce NOx, emissions from diesel fuel alcohol microemulsions (E-diesel) is taught. Ethanol is stripped from the microemulsion and entered into the exhaust gasses upstream of the reducing catalyst. The method allows diesel engines to meet new, lower emission standards without having to carry separate fuel and reductant tanks.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 10 / 361,432 filed Feb. 10, 2003.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH [0002] This invention was made with United States Government support under Contract No. DE-AC05-00OR 22725 between the United States Department of Energy and UT-Battelle, LLC, and the United States Government has certain rights in this invention.FIELD OF THE INVENTION [0003] This invention relates to control of pollution from diesel engines and particularly to methods for enhancing the catalytic reduction of oxides of nitrogen by extracting ethanol from E-diesel for injection into the engine exhaust. BACKGROUND AND PRIOR ART [0004] Diesel-cycle engines have displaced Otto-cycle internal combustion engines in medium and heavy truck use and are becoming increasingly popular for passenger vehicles. The diesel is inherently more efficient but its lack of responsiveness, its noise and its distinctive o...

AI Technical Summary

Benefits of technology

This approach allows for efficient NOx reduction using a single fuel, maximizing fuel economy and emissions control by optimizing ethanol injection and catalyst performance, achieving the required NOx emission standards without the need for separate reductant storage or complex fueling systems.

Problems solved by technology

The diesel is inherently more efficient but its lack of responsiveness, its noise and its distinctive odor historically limited its appeal to commercial trucks and business traveling salesmen and taxicab fleets.

The advent of laws and regulations addressing emissions from “mobile sources” also limited the appeal of diesel cars and light tracks because they were perceived as dirty and regional regulations relating to emissions, especially soot, limited their availability.

Recent advances in fuel injection management in combination with electronic systems have closed the gap but the strategies applied to Otto-cycle engines do not always work with diesels.

Ethanol is readily blended into gasoline, but is difficultly blended into diesel fuel which has a blend of thousands of paraffinic, naphthalenic and aromatic hydrocarbons ranging in carbon numbers between 10 and 22.

A persistent problem for diesel engines has been production of oxides of nitrogen, typically a mixture of NO and NO2 most frequently referred to as NOx.

While oxides of sulphur can be reduced by using ULSADO, the primary source of NOx is nitrogen in the air and the higher temperatures of lean burn engines exacerbates an already known problem.

Ammonia is a viable and affordable method for controlling NOx at fixed sources but is impractical for mobile sources, especially mid-sized and compact cars.

The disadvantage of such a system is that fuel economy is impacted and the fuel must be carefully metered to avoid hydrocarbon emissions.

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