Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration

Parks, James E.; Prikhodko, Vitaly Y.; Partridge, William P.; Choi, Jae‐Soon; Norman, Kevin; Huff, Shean; Chambon, Paul

doi:10.4271/2010-01-2267

Cited by 30 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This may generate relatively high levels of CO, H 2 and HC slippage to the SCR catalyst [11,12]. A recently-commercialized SCR on-filter (SCRF) technology comprises a diesel particulate filter (DPF) that is coated with SCR catalyst and is positioned in close proximity to the engine to enable fast SCR light-off.…”

Section: Generation By the Lntmentioning

confidence: 99%

Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

2016

View full text Add to dashboard Cite

We investigated the steady-state and transient effects of reductants (CO, H 2 and C 3 H 6 ) on NO 2 reduction, NH 3 -SCR (selective catalytic reduction), NH 3 adsorption and oxidation, and N 2 O production on a Cu-SSZ-13 monolithic catalyst. The three reductants affect to different extents the standard SCR (NO + NH 3 + O 2 ), fast SCR (NO + NH 3 + NO 2 ), and slow SCR (NH 3 + NO 2 ). This study underscores the importance of accounting for the impact of reducing agents on conventional NH 3 -SCR reaction mechanism when SCR catalyst is subjected to either rich regeneration of integrated systems (LNT + SCR, SCR on DPF) or cold-start. Propylene is most effective in promoting NO 2 reduction to NO by formation of organic intermediates. CO effectively reduces nitrates to nitrites that then react with NO 2 , releasing NO. H 2 can follow a similar pathway as CO but is less effective. In addition, H 2 can also enable a H 2 -based SCR pathway through the reduction of Cu cations to Cu 0 which then catalyze the NOx reduction. This pathway is particularly evident at high temperatures and low O 2 levels. As for NH 3 -SCR reactions, propylene competes with NH 3 for adsorbed NO 2 , which generates NO and thus increases the NO/NOx ratio. This leads to the dominance of either fast or standard SCR for a slow SCR (NH 3 + NO 2 ) feed condition when C 3 H 6 is present. CO has only a minor effect on both standard and fast SCR but a promoting effect on slow SCR. The ineffective reduction of NO 2 to NO by H 2 at low temperature (T < 250 o C) results in a negligible effect on slow SCR. In contrast to steady-state operation, lean/rich cycling enhances cycle-averaged NOx conversion for each of the NH 3 -SCR reactions when adding either C 3 H 6 or a CO + H 2 mixture in the rich phase. A decreased N 2 O generation rate from the slow SCR reaction is observed when any of the three reductants are present due in part to their reaction with ammonium nitrates.

show abstract

Section: Generation By the Lntmentioning

confidence: 99%

Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

2016

View full text Add to dashboard Cite

show abstract

“…In emerging economies, the implementation of LP seems to be difficult due to the limited resources and behavioral or cultural impacts of the workforce in accordance with the perception of top management in the manufacturing sectors. In order to meet the challenging competition globally, the tendency to use lean techniques in emerging economies has been increasing with the realization that developing countries cannot keep up with the rapidly changing world without the implementation of lean philosophy (Parks et al , 2010). Currently, manufacturing firms in developing countries are encouraged to adopt LP to obtain a competitive advantage (Taj and Morosan, 2011).…”

Section: Discussionmentioning

confidence: 99%

The effect of supply chain agility and lean practices on operational performance: a resource-based view and dynamic capabilities perspective

Manzoor

Baig

Hashim

et al. 2021

TQM

View full text Add to dashboard Cite

PurposeIn today's global economy, developing supply chain agility (SCA) and lean practices (LP) as resource-based view and dynamic capabilities are essential for firms to sustain their competitive advantage (CA) and enhance their operational performance (OP). The purpose of this paper is to develop and empirically test a framework to investigate how CA is achieved through SCA and LP and how these, in turn, can enhance a firm's OP.Design/methodology/approachFor data collection, the authors adopted the survey method using self-administered questionnaires. Two-source survey data were collected in two rounds (separated by a two-month lag time) from supply chain managers, operational managers and general managers. The purpose of collecting data in two rounds was to reduce common-method bias. Likert scale (1–5) was used in the questionnaire. Smart PLS 3 and SPSS 23 were used for the data analysis purpose.FindingsSCA was found to directly and positively affect OP. LP also positively affected OP. In addition, CA fully mediated the relationship between SCA, LP and OP.Practical implicationsThis study encourages the managers of manufacturing firms to adapt LP and their supply chains (SCs) to become agile and leverage the advantages of their implementation to improve their OP and succeed in the market.Originality/valueThis study is one of the first to investigate the effect of SCA and LP on OP. Furthermore, the first study examines CA's mediating impact on the relationship between SCA, LP and OP.

show abstract

“…Stoichiometric exhaust conditions are suitable for a three-way catalyst (TWC) to effectively control NO X , CO, and HC emissions to regulated levels. Lean operation can increase fuel economy of a gasoline engine by as much as 10-20% over stoichiometric [2], [3]. While TWCs can effectively oxidize CO and HCs under lean conditions, they are unable to reduce NO X in the presence of excess oxygen; thus, a different emissions control technology is required for the abatement of NO X emissions from lean-burn gasoline engines.…”

Section: Introductionmentioning

confidence: 99%

“…The controller mimics the original equipment manufacturer (OEM) combustion strategies and, furthermore, enables full control of all engine parameters, including fuel injection quantity and timing, spark timing, λ , and EGR rate which allows full control of the different modes of combustion. Additional information on the engine setup, performance and emissions can be found in [2], [3], [6].…”

mentioning

confidence: 99%

Passive SCR for lean gasoline NOX control: Engine-based strategies to minimize fuel penalty associated with catalytic NH3 generation

et al. 2016

Self Cite

View full text Add to dashboard Cite

Lean gasoline engines offer greater fuel economy than common stoichiometric gasoline engines. However, excess oxygen prevents the use of the current three-way catalyst (TWC) to control nitrogen oxide (NO X) emissions in lean exhaust. A passive SCR concept, introduced by General Motors Global R&D, makes use of a TWC that is already onboard to generate NH 3 under slightly rich conditions, which is stored on the downstream SCR. The stored NH 3 is then used to reduce NO X emissions when the engine switches to lean operation. In this work, the effect of engine parameters, such as air-fuel equivalence ratio and spark timing, on NH 3 generation over a commercial Pd-only TWC with no dedicated oxygen storage component was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine. NO X reduction, NH 3 formation, and reductant utilization processes were evaluated, and fuel efficiency was assessed and compared to the stoichiometric engine operation case. Air-fuel equivalence ratio was found to be one of the most important parameters in controlling the NH 3 production; however, the rich operation necessary for NH 3 production results in a fuel consumption penalty. The fuel penalty can be minimized by adjusting spark timing to increase rich-phase engine out NO X emissions and, thereby, NH 3 levels. Additionally, higher engine out NO X during engine load increase to simulate acceleration resulted in additional fuel savings. A 10% fuel consumption benefit was achieved with the passive SCR approach by optimizing rich air-fuel equivalence ratio and spark timing while also utilizing acceleration load conditions.

show abstract

Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration

Cited by 30 publications

References 6 publications

Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

Effects of CO, H2 and C3H6 on Cu-SSZ-13 catalyzed NH3-SCR

The effect of supply chain agility and lean practices on operational performance: a resource-based view and dynamic capabilities perspective

Passive SCR for lean gasoline NOX control: Engine-based strategies to minimize fuel penalty associated with catalytic NH3 generation

Contact Info

Product

Resources

About