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Reactivity Analysis and Modeling of NOx purification Considering Reactions on Cu active sites and Brønsted acid sites in a Cu-chabazite SCR catalyst

Waseda Univ-TAKAO FUKUMA, Jin Kusaka
Waseda Univ.-Yoshihisa Tsukamoto
  • Technical Paper
  • 2019-24-0150
To be published on 2019-08-15 by SAE International in United States
In this study, the NOx purification reactivity of a Cu-chabazite SCR catalyst was analyzed over a wide temperature range based on the NH3-SCR mechanism considering Cu redox reactions and reactions on a Brønsted acid site. It was revealed that the De-NOx reactions on the active site of Cu proceeded in different paths at lower and higher temperatures. This means that the rate-limiting step of SCR reactions was changed as each temperature. The reaction rate of NOx purification on a Cu site less than 200 °C was determined by the reaction rate of oxidation of Cu sites. On the other hand, the NH3 adsorption on Cu sites played a dominant role in NOx purification at temperature range higher than 300°C. Moreover, it was also observed that the Cu reaction site took different states at low and high temperatures during the NOx purification and was estimated that the valence state of a Cu site was changed as the temperature increased. In order to analyze the reaction on a Brønsted acid site of chabazite structure, analysis using an…
 

Analysis of TWC operation characteristics in a Euro6 gasoline light duty vehicle

Aristotle University Thessaloniki-Grigorios Koltsakis
Empa-Viola Papetti, Panayotis Dimopoulos Eggenschwiler
  • Technical Paper
  • 2019-24-0162
To be published on 2019-08-15 by SAE International in United States
A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during the WLTP cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (Direct oxidation and reduction, selective catalytic re-ductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk Ceria as well as surface Ce-ria reactions). The reactions have been parametrized in order to best approximate the measurements. Based on the reactions taken into account, the real vehicle emissions can be predicted with good accu-racy. The simulations show that the cycle emissions are comprising mainly by the cold start contribution as well as discrete emission break-through events during transients. During cold start no reactions are evident in the catalyst before the temperature of the gas entering the catalyst reaches 270°C. Following the light-off, prevailing reactions are direct oxidation for CO and direct oxidation as well as surface ceria reactions for THC. NO reduction during cold…
 

Effects of In-cylinder flow structures on soot formation and oxidation in a swirl-supported light-duty diesel engine

Lund University-Hesameddin Fatehi, Oivind Andersson
Volvo Cars Corporation-Håkan Persson, Mattias Ljungqvist
  • Technical Paper
  • 2019-24-0009
To be published on 2019-08-15 by SAE International in United States
In this paper, computation fluid dynamics (CFD) simulations are performed to describe the effect of in-cylinder flow structures on the formation and oxidation of soot in a swirl-supported light-duty diesel engine. The focus of the paper is on the effect of swirl motion and injection pressure on late cycle soot oxidation. The structure of the flow at different swirl numbers is studied to investigate the effect that varying swirl number imposes on the coherent flow structures. These coherent flow structures are studied to understand the mechanism that leads to efficient soot oxidation in late cycle. Effect of varying injection pressure at different swirl numbers and the interaction between spray and swirl motions are discussed. The complexity of diesel combustion, especially when soot and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution. In this work, Representative Interactive Flamelets (RIF) method is employed to describe the chemical reactions, ignition, flame propagation and emissions in the engine. The CFD simulations are validated using experimental measurement…
 
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Fault Feature Extraction of Elliptically Shaped Bearing Raceway

South China University of Technology-Yingying Guo, Xuezhi Zhao
Published 2019-06-05 by SAE International in United States
The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the fault features of ESB such as fatigue spalling and pitting are apt to be concealed by the excitation of impulses caused by alternating between major axis and minor axis. In order to diagnose the fault on raceway surfaces of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature. First, the formulas of feature frequency is deduced based on the geometry and kinematics characteristics of ESB; then the CMWT method is employed to decompose the fault signal of ESB; finally, the FH spectrum analysis is performed to extract the feature frequency of faulty ESB from the decomposition signal with the maximum kurtosis in the first several layers. Compared with the traditional FH method, the feature…
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Cleaner for Exterior Aircraft Surfaces Thickened or Gel-Type, Water-Base

AMS J Aircraft Maintenance Chemicals and Materials Committee
  • Aerospace Material Specification
  • AMS1523B
  • Current
Published 2019-06-03 by SAE International in United States
This specification covers a thickened, water-base, type cleaner in the form of a gel.
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COMPOUND, ALKALINE RUST REMOVER Aircraft Turbine Engine Components

AMS J Aircraft Maintenance Chemicals and Materials Committee
  • Aerospace Material Specification
  • AMS1379A
  • Current
Published 2019-06-03 by SAE International in United States
This specification covers an alkaline rust remover compound in the form of a liquid concentrate or a water-soluble powder for dilution with water.
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Bolt, Machine-Hexagon Drilled, 6 Holes, Full Shank, Corrosion and Heat Resistant Steel, UNS S66286, 130 KSI Min, .3750-24 UNJF-3A

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • AS9586C
  • Current
Published 2019-06-03 by SAE International in United States

Scope is unavailable.

 
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Eliminating Corrosion Extends Life of Lightweight Batteries

  • Magazine Article
  • TBMG-34618
Published 2019-06-01 by Tech Briefs Media Group in United States

Metal-air batteries are one of the lightest and most compact types of batteries but when not in use, they degrade quickly, as corrosion eats away at their metal electrodes. While typical rechargeable lithium-ion batteries only lose about 5 percent of their charge after a month of storage, they are too costly, bulky, or heavy for many applications. Primary (non-rechargeable) aluminum-air batteries are much less expensive and more compact and lightweight, but they can lose 80 percent of their charge a month.

 
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Nickel-Iron Alloy, Magnetic, Sheet and Strip 50Ni - 50Fe Stamping Quality, Half-Hard Temper

AMS E Carbon and Low Alloy Steels Committee
  • Aerospace Material Specification
  • AMS7719E
  • Current
Published 2019-05-29 by SAE International in United States
This specification covers a magnetic nickel-iron alloy in the form of sheet and strip.
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Nickel-Iron Alloy, Magnetic, Bars, Rods, Tubing, and Forgings 50Ni - 50Fe

AMS E Carbon and Low Alloy Steels Committee
  • Aerospace Material Specification
  • AMS7718H
  • Current
Published 2019-05-29 by SAE International in United States
This specification covers a magnetically soft nickel-iron alloy in the form of bars, rods, forgings, mechanical tubing, and forging stock.
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