Method for Increasing Catalyst Temperature Using Ethanol-Blended Diesel Fuels

Abstract

A method for managing the temperature of an E-diesel catalyst by distilling out a portion of the ethanol, injecting the distilled ethanol into exhaust gasses upstream of the catalyst, reacting the distilled ethanol with excess oxygen in the exhaust gasses to produce heat, and controlling the ethanol injection using various engine parameters.

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

The invention provides a method for reducing NOx in diesel exhaust by using a single fuel for both power and NOx control. This is achieved by separating components of the fuel to maximize fuel economy, emissions control, and catalyst temperature control. The method involves stripping ethanol from E-diesel and injecting it into the exhaust stream using engine heat and manifold vacuum. The ethanol reacts with excess oxygen in the exhaust gases to produce heat, which is controlled using engine parameters such as intake air flow, fuel mixture richness, engine operating temperature, catalyst temperature, and NOx sensor output.

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.

Images