Diesel Emission Control in Review

Johnson, Timothy V.

doi:10.4271/2006-01-0030

Cited by 92 publications

(17 citation statements)

References 28 publications

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“…As one of the key pollutants of the lower atmosphere, NO X plays a significant role in the atmospheric chemical reactions that create harmful acid rain, photochemical smog, and particulate matter . The impacts caused by NO X emissions have cost society billions of dollars annually from illnesses and deaths; consequently, greater emphasis is needed on controlling NO X emissions.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation on the urea injection and mixing module for improving the performance of urea‐SCR in diesel engines

Liu

2017

Can J Chem Eng

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In a urea selective catalytic reduction (urea‐SCR) system for diesel engines, the atomization, evaporation, and mixing conditions of urea water solution (UWS) play a crucial role for NOX conversion and ammonia slip in the SCR process. In this paper, a series of novel mixing modules were proposed to improve UWS evaporation, mixing, and distribution for NOX reduction in the SCR system. Experimental investigations were conducted on the performances of the existing and developed mixing modules under various engine test conditions, including particle size test, NOX conversion efficiency, flow bench tests, etc. To determine ammonia slip, the urea and ammonia distribution patterns were constructed and the non‐uniformity index was then calculated. Compared with the baseline (without mixing module) and existing mixing module, the NOX conversion efficiency of the SCR system with a developed mixing module is improved by 37.7 and 14.1 % at maximum, respectively. Furthermore, ammonia slip and distribution are ameliorated significantly with low‐pressure drops simultaneously. Among the mixing modules, Concept 3 design exhibits superior performance under the engine test conditions.

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Section: Introductionmentioning

confidence: 99%

“…Among the more stringent exhaust emission regulations of vehicles, the emission regulation of NO X becomes the most challenging task to be achieved; therefore, engine raw emission and after‐treatment requirements are focused on NO X . Scholars and professionals have investigated NO X emissions‐reducing technologies for many years.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the urea injection and mixing module for improving the performance of urea‐SCR in diesel engines

Liu

2017

Can J Chem Eng

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“…NO 2 in turn is used to help remove carbon particles from the filter to prevent it from plugging. With a passive filter NO 2 emissions are dependent on the NO x flux and exhaust temperature (7). Other approaches and many variations on the above examples exist; emissions vary based on the oxidative capacity of the filter and other factors (8).…”

Section: Introductionmentioning

confidence: 99%

“…Other approaches include lean NO x traps (LNT) that periodically regenerate by reducing NO x with fuel, and lean NO x catalysts that adsorb NO x under lean conditions and can also use fuel to reduce the NO x to N 2 . Conversion efficiencies of lean NO x traps and catalysts have not matched SCR, however, development is ongoing (7).…”

Section: Introductionmentioning

confidence: 99%

Effects of Retrofitting Emission Control Systems on In-Use Heavy Diesel Vehicles

Millstein

Harley

2010

Environ. Sci. Technol.

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Diesel engines are now the largest source of nitrogen oxides (NO x ) and fine particulate black carbon (soot) emissions in California. The California Air Resources Board recently adopted a rule requiring that by 2014 all in-use heavy trucks and buses meet current (2007) exhaust particulate matter (PM) emission standards. Also by 2023 all in-use heavy-duty vehicles will have to meet current NO x emission standards, with significant progress in achieving the requirements for NO x control expected by 2014. This will require retrofit or replacement of older in-use engines. Diesel particle filters (DPF) reduce PM emissions but may increase the NO 2 /NO x emission ratio to ∼35%, compared to ∼5% typical of diesel engines without particle filters. Additionally, DPF with high oxidative capacity reduce CO and hydrocarbon emissions. We evaluate the effects of retrofitting trucks with DPF on air quality in southern California, using an Eulerian photochemical air quality model. Compared to a 2014 reference scenario without the retrofit program, black carbon concentrations decreased by 12 ( 2% and 14 ( 2% during summer and fall, respectively, with corresponding increases in ambient ozone concentrations of 3 ( 2% and 7 ( 3%. NO 2 concentrations decreased by 2-4% overall despite the increase in primary NO 2 emissions because total NO x emissions were reduced as part of the program to retrofit NO x control systems on in-use engines. However, in some cases NO 2 concentrations may increase at locations with high diesel truck traffic.

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“…In the oxidation method, inorganic oxide materials are added into the diesel fuel as additives admixture to remove the accumulated PM. On the other hand, the physical removal method is hardly used because of its ineffectiveness [3,7]. Ash materials of sulfates, phosphates, or other oxides of calcium and zinc are formed from the burned additives of the engine lubricant in the engine's combustion chamber.…”

Section: Introductionmentioning

confidence: 99%