Development of Test Methods for Lean-NOx Catalyst Evaluation

Litorell, Martin; Allansson, Ronny; Andreasson, Anders; Fredholm, S.; Hawker, Pelham; Johansson, Börje; Lööf, Peter; Smedler, Gudmund

doi:10.4271/952489

Cited by 3 publications

(2 citation statements)

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“…Lean NO x catalysts provide a catalytic reduction of NO x emissions in a fuel-lean environment. It is envisioned that lean NO x catalysts will not be incorporated as part of the aftertreatment by the year 2004 (Litorell, 1995 and that the systems were very sensitive to poisoning by SO 2 , and inhibition by water (Browning, 1997). Platinum-based catalysts are quite active in reducing NO x emissions in the 200°C to 300°C range and need lower amounts of HC to reduce NO x (2 to 1).…”

Section: Lean No X Catalystsmentioning

confidence: 99%

“…The most significant problem with lean NO x catalysts is the need for a large amount of a reductant (hydrocarbons). Current lean NO x catalysts also prefer lower molecular weight hydrocarbons such as propane (Litorell, 1995). However, it is clear for such a system to be realistic on diesel engines, it must use diesel fuel as the source of hydrocarbons.…”

Section: Lean No X Catalystsmentioning

confidence: 99%

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Influence of fuel sulfur content on emissions from diesel engines equipped with oxidation catalysts

Evans¹

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Diesel oxidation catalysts (DOCs) are a viable exhaust aftertreatment alternative for alleviating regulated exhaust emissions of hydrocarbon (HC), carbon monoxide (CO), and particulate matter (PM) from diesel-fueled heavy-duty engines. This study was a part of the Diesel Emissions Control-Sulfur Effects (DECSE) program that was aimed at determining the impact of diesel fuel sulfur levels on diesel oxidation catalysts that were designed to lower brake-specific PM, HC, and CO emissions from on-highway trucks and buses in the 2002-2004 model years. The research focused on high-temperature DOCs installed on a Cummins ISM370 ESP engine, and low-temperature DOCs installed on a Navistar T444E engine to determine how the DOCs affect the various emissions, how fuel sulfur affects emissions, and how fuel sulfur poisons the catalysts over time. The DOCs were found to affect the brake-specific PM, HC, and CO emissions. The PM emissions were not significantly affected by the DOCs when lower sulfur fuels (3 ppm and 30 ppm) were used. Brake-specific PM emissions were dramatically increased with the higher sulfur fuel (350 ppm) due to the formation of sulfates and the associated sulfate bound water. Hence, fuel sulfur affected the brake-specific PM, HC, and CO emissions from DOC equipped heavy-duty diesel engines. Brake-specific HC emissions were eliminated by nearly 100% by the use of the DOCs. The DOCs had various reduction efficiencies ranging from 90% to 100% for CO emissions from the Navistar engine and 24% to 79% for the Cummins engine. The DOCs were only evaluated for only 250 aging hours, which is a relatively short duration. Over this short amount of time, there was no significant evidence of the fuel sulfur poisoning the diesel oxidation catalysts. iii ACKNOWLEGDEMENTS After six years of college education, a part of my life has finally ended. However, there is another part about to begin. Through the past two years of graduate school I have encountered some rough times, but it seemed that the better always won. As I look back on these past two years, I know I could not have accomplished everything on my own. I would like to take this time to express my thanks to the ones that helped see me through this challenging and rewarding time. The first and foremost who needs to be recognized is God. I would never be here if were not for Him. Even though He is unseen, I know His presence is always with me. He needs to be recognized due to the fact that too often He does go unacknowledged. Now to my parents, where I believe there is not enough time and words to show my appreciation and gratitude. Mom and Dad, without your love, encouragement, understanding, and support, I know none of this could have been possible. You have been there for me all the way, and I know you will always be there for me in the future. I can't express how much I love the two of you for this. You need to be recognized for one huge accomplishment, financially supporting three boys through engineering school. Dad, I know it was a lot of hard work for you, a...

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Section: Lean No X Catalystsmentioning

confidence: 99%

Section: Lean No X Catalystsmentioning

confidence: 99%