Study on pollutant emission characteristics of different types of diesel vehicles during actual road cold start

Tang, Gangzhi; Wang, Shuaibin; Du, Baocheng; Cui, Lianbo; Huang, Yaxing; Xiao, Wei

doi:10.1016/j.scitotenv.2022.153598

Cited by 21 publications

(8 citation statements)

References 8 publications

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“…3,4 Besides catalytic activity, excellent hydrothermal stability is also required for SCR catalysts because high temperature and humid conditions are frequently generated during the regeneration of the upstream diesel particulate filter. 5 Additionally, remarkable low-temperature activity is also crucial for SCR catalysts, especially after hydrothermal treatment, as up to 40−90% of NO x is emitted during the cold start process, 6,7 and the exhaust temperature would be further decreased with the development of internal combustion engines. 8,9 Cu-SSZ-13 zeolite (CHA-type) with a Si/Al ratio of ∼10 has been commercialized in NO x removal from diesel vehicles' exhaust for its wide temperature window and high hydrothermal stability.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Nitrogen oxide (NO x ) emissions, mainly originated from diesel engines, have caused a wide range of environmental concerns. , Selective catalytic reduction with ammonia (NH 3 –SCR) has been widely recognized as the dominant technology to remove NO x from diesel vehicles to meet the increasingly stringent emission standard. , Besides catalytic activity, excellent hydrothermal stability is also required for SCR catalysts because high temperature and humid conditions are frequently generated during the regeneration of the upstream diesel particulate filter . Additionally, remarkable low-temperature activity is also crucial for SCR catalysts, especially after hydrothermal treatment, as up to 40–90% of NO x is emitted during the cold start process, , and the exhaust temperature would be further decreased with the development of internal combustion engines. , …”

Section: Introductionmentioning

confidence: 99%

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Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃

Han,

Li,

Zhao

et al. 2024

J. Am. Chem. Soc.

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Cu-SSZ-13 has been commercialized for selective catalytic reduction with ammonia (NH 3 −SCR) to remove NO x from diesel exhaust. As its synthesis usually requires toxic and costly organic templates, the discovery of alternative Cu-based zeolite catalysts with organotemplate-free synthesis and comparable or even superior NH 3 −SCR activity to that of Cu-SSZ-13 is of great academic and industrial significance. Herein, we demonstrated that Cu-T with an intergrowth structure of offretite (OFF) and erionite (ERI) synthesized by an organotemplate-free method showed better catalytic performance than Cu-ERI and Cu-OFF as well as Cu-SSZ-13. Structure characterizations and density functional theory calculations indicated that the intergrowth structure promoted more isolated Cu 2+ located at the 6MR of the intergrowth interface, resulting in a better hydrothermal stability of Cu-T than Cu-ERI and Cu-OFF. Strikingly, the lowtemperature activity of Cu-T significantly increased after hydrothermal aging, while that of Cu-ERI and Cu-OFF substantially decreased. Based on in situ diffuse reflectance infrared Fourier transform spectra analysis and density functional theory calculations, the reason can be attributed to the fact that NH 4 NO 3 formed on the Cu x O y species within ERI polymorph of Cu-T underwent a fast SCR reaction pathway with the assistance of Brønsted acid sites at the intergrowth interfaces under standard SCR reaction conditions. Significantly, Cu-T exhibited a wider temperature window at a catalytic activity of over 90% than Cu-SSZ-13 (175−550 vs 175−500 °C for fresh and 225−500 vs 250−400 °C for hydrothermal treatment). This work provides a new direction for the design of high-performance NH 3 −SCR catalysts in terms of the interplay of the intergrowth structure of zeolites.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃

Han,

Li,

Zhao

et al. 2024

J. Am. Chem. Soc.

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“…The introduction of Real Driving Emissions (RDE) testing and the Worldwide harmonized Light vehicles Test Cycles (WLTC) within the Worldwide harmonized Light vehicles Test Procedure (WLTP) framework aims to narrow the gap between homologation and real-world emissions of Internal Combustion Engines (ICE) [2]. However, research indicates that vehicles meeting current standards still emit significant pollutants under specific conditions, such as cold starts [3], short trips [4], and scenarios involving high altitudes [5] or extreme ambient temperatures [6]. Current RDE tests establish environmental limits to assess vehicle emissions control in real-world driving scenarios [7].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Altitude and Ambient Temperature Effects on the Reactivity of Oxidation Catalysts in the Presence of H2

Serrano,

Piqueras,

Sanchis

et al. 2024

Preprint

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Worldwide emission standards are now required to cover engine operation under extreme ambient conditions, which affect the raw emissions and the efficiency of the exhaust aftertreatment systems. These regulations also target new combustion technologies for decarbonization, such as neat hydrogen (H2) combustion or dual-fuel strategies, which involve a challenge to the analysis of exhaust aftertreatment systems requirements and performance. This work addresses the impact of high altitude and low ambient temperature conditions on the reactivity of an oxidation catalyst in the presence of H2. A reaction mechanism is proposed to cover the main conversion paths of CO, HC, and H2, including the formation and consumption of high-energy surface reaction intermediates. The mechanism has been implemented into a faster-than-real-time reduced-order model for multi-layer washcoat honeycomb catalytic converters. The model was utilized to investigate the effect of H2 concentration on the reactivity of CO and HC within the catalyst under various operating and ambient conditions. By applying the model and examining the selectivity towards different reaction pathways in the presence H2, insights into surface intermediates and reactivity across different cross-sections of the monolith were obtained. This analysis discusses the underlying causes of reactivity changes promoted by H2 and its relative importance as a function of driving boundary conditions.

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“…Pacaud et al [19] found that as ambient temperature increases from −2 • C to 32 • C, the CO and HC emitted by a diesel engine could decrease by 87.5% and 75%, respectively. Tang et al [20] found that the emissions of heavy vehicles were relatively high during cold starts. NO X emissions, in particular, could account for 40% to 90% of the total engine working process during a cold start.…”

Section: Introductionmentioning

confidence: 99%

Strategies to Reduce Emissions from Diesel Engines under Cold Start Conditions: A Review

Zhang

Huang

et al. 2023

Energies

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Reducing diesel engine emissions under cold start conditions has become much more valuable as environmental issues become more important. Regarding diesel engine emissions under cold start conditions, this review summarizes the emission mechanisms and specifically focuses on the research progress of four reduction strategies: biodiesel utilization, intake heating, injection optimization, and aftertreatment technologies. In general, adding biodiesel and Di-Ethyl-Ether (DEE) could provide the benefit of reducing emissions and maintaining engine performance. Intake heating and appropriate injection strategies could also effectively reduce emissions under cold start conditions. Unlike normal operating conditions, lean nitrogen oxide traps (LNT) or electrically heated catalysts (EHC) should be utilized in the aftertreatment of diesel engines to minimize emissions under cold start conditions. By offering the valuable information above, this review could be a helpful reference in reduction strategies for diesel engines under cold start conditions in both academia and industry.

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Study on pollutant emission characteristics of different types of diesel vehicles during actual road cold start

Cited by 21 publications

References 8 publications

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃

Analysis of Altitude and Ambient Temperature Effects on the Reactivity of Oxidation Catalysts in the Presence of H2

Strategies to Reduce Emissions from Diesel Engines under Cold Start Conditions: A Review

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Study on pollutant emission characteristics of different types of diesel vehicles during actual road cold start

Cited by 21 publications

References 8 publications

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NOx with NH3

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NOx with NH3

Analysis of Altitude and Ambient Temperature Effects on the Reactivity of Oxidation Catalysts in the Presence of H2

Strategies to Reduce Emissions from Diesel Engines under Cold Start Conditions: A Review

Contact Info

Product

Resources

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Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃

Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NO_x with NH₃