Characterizing the Influence of EGR and Fuel Pressure on the Emissions in Low Temperature Diesel Combustion Texas A&M University

Format:

Conference/Event

Author/Creator:

Knight, Knight, author.

Contributor:

Bittle, Joshua A.

Jacobs, Timothy J.

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

In the wake of global focus shifting towards the health andconservation of the planet, greater importance is placed upon thehazardous emissions of our fossil fuels, as well as their finitesupply. These two areas remain intense topics of research in orderto reduce greenhouse gas emissions and increase the fuel efficiencyof vehicles, a sector which is a major contributor to society'sglobal CO₂ emissions and consumer of fossil-fuel resources. Aparticular solution to this problem is the diesel engine, with itsinherently fuel-lean combustion, which gives rise to low CO₂production and higher efficiencies than other potential powertrainsolutions.Diesel engines, however, typically exhibit higher nitrogenoxides (NOx) and soot engine-out emissions than theirgasoline counterparts. NOx is an ingredient toground-level ozone production and smoke is a possible carcinogen,both of which are facing stricter emissions regulations. Thetypical diesel engine exhibits a NOx - soot tradeoffwhere a reduction in NOx results in an increase in soot,and vice versa. There exists the possibility to simultaneouslyreduce both emissions with the application of low temperaturediesel combustion, or LTC. LTC allows for low flame temperatureswithin the combustion, in order to prohibit both soot andNOx formation, while at the same time allowing forpremixed combustion to eliminate fuel-rich combustion zones whichfurther reduces soot formation. While exhibiting greatcharacteristics in simultaneous reductions in nitrogen oxides andsoot, LTC faces challenges with carbon monoxide (CO) emissions,hydrocarbon (HC) emissions, penalties in fuel efficiency, anddifficulty in attainment during high loads.The following study examines the characteristics of LTC whichcontribute to the differences in emissions and efficiency comparedto typical conventional diesel combustion. More specifically, keyengine parameters which are used to enable LTC, such as EGR andfuel pressure are swept through a full range to determine theireffects on each combustion regime. Analysis will focus on comparingboth combustion regimes to determine how EGR and fuel pressurerelate to lowering NOx and smoke concentrations, and howthese relate to penalties in CO and HC concentrations.This study identifies that with the application of LTC on aconventional combustion diesel engine, a 99% reduction in NOemissions and a 15% simultaneous reduction in smoke can berealized. The typical soot - NO tradeoff is reduced withapplication of EGR, relative to conventional combustion operation.Further, increasing fuel pressure shows typical increases in NO anddecreases in smoke for both LTC and conventional combustion, thussuggesting that LTC may not necessarily defeat the soot-NOtradeoff, but shift its behavior to lower NO/soot concentrationregimes

Notes:

Vendor supplied data

Publisher Number:

2011-01-1354

Access Restriction:

Restricted for use by site license