Development of Highly Efficient Lean NOx Catalyst System in Low Exhaust Gas Temperature

Matsuo, Yuichi; Ishimaru, Shin; Amano, Masato; Komatsu, Noriyuki; Aoyagi, Satoshi; Dan, Hiroyuki; Endo, Tetsuo; Matsuzono, Yoshiaki; Ito, Tomoaki; Nagata, Makoto

doi:10.4271/2013-01-0536

Cited by 13 publications

(3 citation statements)

References 11 publications

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“…The reduction of vehicle emissions, particularly the emissions of nitrogen oxides (NOx) and particulate matter (PM), remains an important engineering challenge and the enforcement of progressively more stringent emission regulations has compelled lean-burn engine manufacturers to research and develop advanced in-cylinder and after-treatment emission reduction technologies [1][2][3][4]. In-cylinder technologies, such as exhaust gas recirculation (EGR) and advanced fuel injection strategies, can reduce the formation of NOx and PM emissions from lean-burn engines but they can also lead to an increase in the unburned hydrocarbon emissions and a reduction in the fuel economy [5,6].…”

Section: Introductionmentioning

confidence: 99%

A study of the effect of post injection on combustion and emissions with premixing enhanced fueling strategies

Jeftić

Zheng

2015

Applied Energy

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Section: Introductionmentioning

confidence: 99%

A study of the effect of post injection on combustion and emissions with premixing enhanced fueling strategies

Jeftić

Zheng

2015

Applied Energy

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“…Intermittent in-cylinder rich combustion or injection of fuel into the exhaust produce an exhaust containing a stoichiometric surplus of CO, H 2 and hydrocarbons (HC) [5,6]. The operation temperature window for LNT catalysts is relatively narrow (250-400 °C ) [7]. The low-temperature LNT performance is limited by an incomplete regeneration, as well as by low rates of NO oxidation.…”

Section: Commercial Lean Nox Abatement Technologies Include Selectivementioning

confidence: 99%

Rapid propylene pulsing for enhanced low temperature NO conversion on combined LNT-SCR catalysts

Zheng

Wang

et al. 2016

Catalysis Today

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Lean reduction of NOx (NO + NO 2) was conducted over combined LNT-SCR dual-layer and zoned monolithic catalysts using rapid propylene periodic pulsing into a lean feed. We investigated the effects of cycling frequency, reaction exotherm, hydrocarbon (HC) intermediates, top-layer material, LNT ceria content and catalyst configuration on the performance of dual-layer catalysts under fast propylene pulsing. High frequency propylene injection expands the operating temperature window of a conventional NOx storage and reduction (NSR) system in both low and high-temperature regions. The combination of rapid propylene pulsing and the dual-layer catalyst architecture achieves a low-temperature NOx conversion of up to 80% at a feed temperature of ca. 200 °C and relevant space velocities (~ 70k h −1). The working mechanisms of rapid propylene pulsing on both LNT and LNT-SCR catalysts are discussed. Fast cycling facilitates the generation of partially oxidized hydrocarbon intermediates over the LNT that can then either directly react with NOx or act as oxygen scavenger to maintain Pt in a reduced state for direct NO decomposition. The SCR top-layer traps partially oxygenated species that desorb from the LNT layer, enabling further production of N 2 through a LNT-assisted HC-SCR pathway. Optimization of ceria content, top-layer material and catalyst configuration like SCR and PGM zoning can improve system performance at lower cost.

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“…2,3 To overcome harmful emissions from vehicles, stringent regulations are implemented by regulatory authorities 4 which is still one of the biggest challenges for vehicle manufacturers to meet these emissions norms. 5,6 Many emissions reduction technologies are adopted and researchers are still trying to improve the after-treatment and in-cylinder emission reduction technologies 7,8 to minimize these emissions by using advanced systems 9 like exhaust gas recirculation (EGR) 10 and multiple injections technologies. [11][12][13] Diesel Oxidation Catalyst (DOC), 14 Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), 15 and Lean NOx Trap (LNT) 16 have been implemented to control harmful emissions but these technologies are very complex and require multiple devices.…”

Section: Introductionmentioning

confidence: 99%

Effect of post-injection strategies on regulated and unregulated harmful emissions from a heavy-duty diesel engine

Farhan

Wang

et al. 2020

International Journal of Engine Research

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An experimental study was carried out to analyze the influence of different post-injection strategies on the regulated and unregulated emissions from a heavy-duty compression ignition (CI) diesel engine. FTIR (Fourier transform infrared spectroscopy) was used to measure and analyze the exhaust emissions which include regulated such as NOx, soot, and unregulated emissions including acetaldehyde, formaldehyde, methane, ethane, propane, ethylene, propylene, and ethyne. Experimental results manifested that the post-injection technique can notably minimize the regulated and unregulated emissions as compared to a single main injection. Under different post-injection conditions, a trade-off relation was also found between soot and NOx emissions. In soot mitigation, the start of injection (SOI) at 40° crank angle (CA) incorporate with 5–15 mg post-injection fuel mass was proved very effective and about 26% lower soot emissions were recorded than single main injection. At SOI 20°CA, with 15 mg post-injection fuel mass, a reduction in the NOx emissions was observed up to 20% and in THC up to 60%. Unregulated emissions (other than formaldehyde and acetaldehyde) were found lower with 5, 10, and 15 mg post-injection fuel mass at 20, 40, 100, and 120°CA but increased at SOI of 60°CA than single main injection. In addition, light HCs, and THC emissions at SOI 60°CA were found to increase which could be beneficial for after-treatment devices.

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Development of Highly Efficient Lean NOx Catalyst System in Low Exhaust Gas Temperature

Cited by 13 publications

References 11 publications

A study of the effect of post injection on combustion and emissions with premixing enhanced fueling strategies

A study of the effect of post injection on combustion and emissions with premixing enhanced fueling strategies

Rapid propylene pulsing for enhanced low temperature NO conversion on combined LNT-SCR catalysts

Effect of post-injection strategies on regulated and unregulated harmful emissions from a heavy-duty diesel engine

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