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Languages : en
Pages :
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Core samples cut from full size commercial Fe-and Cu-zeolite SCR catalysts were exposed to a slipstream of raw engine exhaust from a 1.9-liter 4-cylinder diesel engine operating in conventional and PCCI combustion modes. Subsequently, the NOx reduction performance of the exposed catalysts was evaluated on a laboratory bench- reactor fed with simulated exhaust. The Fe-zeolite NOx conversion efficiency was significantly degraded, especially at low temperatures (
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Languages : en
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A light-duty diesel engine has been operated in advanced combustion modes known generally as premixed charge compression ignition (PCCI). The emissions have been characterized for several load and speed combinations. Fewer NOx and particulate matter (PM) emissions are produced by PCCI, but higher CO and hydrocarbon (HC) emissions result. In addition, the nature of the PM differs from conventional combustion; the PM is smaller and has a much higher soluble organic fraction (SOF) content (68% vs. 30% for conventional combustion). Three catalyst technologies were studied to determine the affects of HECC on catalyst performance; the technologies were a lean NOx trap (LNT), diesel oxidation catalyst (DOC), and diesel particulate filter (DPF). The LNT benefited greatly from the reduced NOx emissions associated with PCCI. NOx capacity requirements are reduced as well as overall tailpipe NOx levels particularly at low load and temperature conditions where regeneration of the LNT is difficult. The DOC performance requirements for PCCI are more stringent due to the higher CO and HC emissions; however, the DOC was effective at controlling the higher CO and HC emissions at conditions above the light-off temperature. Below light-off, CO and HC emissions are problematic. The study of DPF technology focused on the fuel penalties associated with DPF regeneration or 'desoot' due to the different PM loading rates from PCCI vs. conventional combustion. Less frequent desoot events were required from the lower PM from PCCI and, when used in conjunction with an LNT, the lower PM from less frequent LNT regeneration. The lower desoot frequency leads a ≈3% fuel penalty for a mixture of PCCI and conventional loads vs. ≈4% for conventional only combustion.
Author: B. Ashok
Publisher: Elsevier
ISBN: 0128242280
Category : Technology & Engineering
Languages : en
Pages : 488
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Book Description
NOx Emission Control Technologies in Stationary and Automotive Internal Combustion Engines: Approaches Toward NOx Free Automobiles presents the fundamental theory of emission formation, particularly the oxides of nitrogen (NOx) and its chemical reactions and control techniques. The book provides a simplified framework for technical literature on NOx reduction strategies in IC engines, highlighting thermodynamics, combustion science, automotive emissions and environmental pollution control. Sections cover the toxicity and roots of emissions for both SI and CI engines and the formation of various emissions such as CO, SO2, HC, NOx, soot, and PM from internal combustion engines, along with various methods of NOx formation. Topics cover the combustion process, engine design parameters, and the application of exhaust gas recirculation for NOx reduction, making this book ideal for researchers and students in automotive, mechanical, mechatronics and chemical engineering students working in the field of emission control techniques. Covers advanced and recent technologies and emerging new trends in NOx reduction for emission control Highlights the effects of exhaust gas recirculation (EGR) on engine performance parameters Discusses emission norms such as EURO VI and Bharat stage VI in reducing global air pollution due to engine emissions
Author: Elmer Herman Haux
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 16
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Book Description
Author: Ronald M. Heck
Publisher: Van Nostrand Reinhold Company
ISBN:
Category : Science
Languages : en
Pages : 232
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Book Description
Description of the catalytic challenges for five different fuel cell technologies and hydrogen generation for fuel cell applicationsAmbient air cleanup from mobile and stationary sourcesThis book also contains an extensive bibliography with simplified descriptions of key parameters for compliance with worldwide regulations. The Second Edition of Catalytic Air Pollution Control promises to be an essential professional companion for all scientists and engineers including air pollution engineers, automotive engineers, chemists, chemical engineers working on emission control, and regulators.
Author: N. Kruse
Publisher: Elsevier
ISBN: 0080528619
Category : Technology & Engineering
Languages : en
Pages : 719
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Book Description
In spite of the energy crises and the recession, there has been a global, explosive growth in the amount of motor vehicles. In the past 50 years, the amount has increased from 50 to 700 million vehicles. For economical reasons they will probably continue to be used for a considerable number of years, despite the poor yield of internal combustion engines resulting in the inevitable production of some gaseous pollutants. The subsequent increase of gaseous pollutants in our atmosphere caused by exhaust gas from automobiles has enhanced the problem of the elimination of these pollutants produced by internal combustion engines. Catalysis has proven to be the best solution to lower the content of exhaust gas in pollutants.As its predecessors, CAPoC4 proved to be a suitable platform for discussing technological improvements and developments along with future perspectives and challenges. In the light of new results and further legislative regulations, the following topics were intensely discussed: *low light-off behaviour based on improved catalysts and substrate formulations *efficient adsorber systems for storage of hydrocarbon emissions *electrically heated catalyst systems ahead the main catalyst or, alternatively, close coupled catalysts (at the manifold of the engine) • lean DeNOx catalysts allowing for decomposition of NOx in the oxygen-rich exhaust of direct injection gasoline engines and high speed injection diesel engines or, alternatively, NOx trapping/reduction in a hybrid approach * collection and destruction of dry particulates or soot.There is no doubt that clean vehicle technology is a vital part of improving air quality. Challenges remain and call for technological answers. Catalytic air pollution control is still an area providing a considerable incentive for innovative work.
Author: Juan Miralles Munita
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In Research & Development, the simulation of the aftertreatment systems has become a fundamental part in the development process for the automobile industry. It is normal then to study individually every aftertreatment technology in order to create simulation models for these technologies such as Selective Catalytic Reduction (SCR), Diesel Oxidation Catalyst (DOC) or Diesel Particle Filter (DPF). For helping the creation of these models, dedicated experiments are carried out. These kinetic experiments must be designed and well-defined such that they provide the necessary information in a reproducible way at minimal time and costs. In the first part of the work and in order to facilitate measurements with long SDPF specimens, a reactor with a new oven design has been characterized. Its thermal behaviour and the absence of unwanted reactions of the bare reactor (without catalyst) have been checked. In a previous work, dedicated kinetic measurement procedures for the SCR calibration process were determined and optimized on a synthetic gas test rig. The optimal settings and procedures were programed in the test rig control software. In the second part of this work, several measurements based on these optimal procedures have been carried out on the test rig with a state-of-the-art Cu-Ze SCR to investigate the influence of several types of HCs on the SCR behaviour. The alternative of the NO2/NOx ratio step concept was used for the NOx conversion study of the SCR catalyst. It has been seen that the presence during the experiment of different HC species such as C3H6 and C2H2 had an negative effect in the NOx reduction, and for other HC species as C3H8 the effect was practically inexistent. The results of this work will help to better understand the behaviour of SCR catalysts and SDPF filters for future investigations.
Author: M. Sideris
Publisher: Elsevier
ISBN: 0080536492
Category : Technology & Engineering
Languages : en
Pages : 465
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Book Description
The dramatic evolution of catalytic converters in the last thirty years was a result of a need worldwide to reduce pollution created by the exhaust gases of internal combustion engines. Environmental concerns have led American, Japanese and European Union (EU) legislation to pose continuously stricter emission limits for petrol engines in the last decades. The catalytic converter has become the most important means of exhaust treatment to achieve the desired emission limits. The international legislation has also created a need for a regular assessment of the efficiency of the catalytic converter in order to detect a deterioration of its conversion efficiency as soon as this deterioration takes place. The assessment of conversion efficiency of a catalytic converter can take place during normal driving of a vehicle (on-board diagnosis or OBD) or in a workshop by specialized technicians. The most important methods nowadays are the OBD methods. The evolution of methods concerned with OBD and non-OBD monitoring and diagnosing of efficiency of catalytic converters of internal combustion engines is described based on patents and published patent applications. Non-patent references are also used. The basic principles of modern catalytic converters are described in an extensive Introduction, where the importance of monitoring and diagnosing the efficiency of catalytic converters is demonstrated. The book is divided into four parts. The first part describes methods involving the use of oxygen or air/fuel exhaust gas sensors to determine the oxygen storage capacity of a catalytic converter. The second part describes methods involving the use of temperature sensors to determine the exothermic reaction capacity of a catalytic converter. The third part describes all other methods existing in patent literature that monitor and diagnose the efficiency of catalytic converters. The great majority of the methods of the third part involves exhaust gas concentration measurements. The fourth part comprises a general discussion of all methods described. In the beginning of each part, a short introduction is given to explain the problem that the methods attempt to solve. The methods in each part are presented in chronological order per patent applicant. This helps to evaluate how the patent applicant has improved his methods over time. A patent number index with information about the patent applicants, inventors, priorities and patent-families, an inventor index, a company index and a subject index can be found at the end of the book.
Author: Kathleen C. Taylor
Publisher: Springer Science & Business Media
ISBN: 3642694861
Category : Science
Languages : en
Pages : 61
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Book Description
The use of catalytic converters for the purification of automotive exhaust gases is a relatively new technology which was brought into existence by social pressures for the preservation of acceptable environmental conditions. The majority of catalytic practitioners have been able to watch the growth of this technology from its inception to its current state of sophistication. Automotive catalytic converter technology is now in a mature state, and this chapter from Vol. 5 Catalysis: Science and Technology by Dr. K. C. Taylor provides a review which covers both the process chemistry and the most important converter design factors. Contents 1. Introduction. . . . . . . . . . . . . . 2. Emission Regulations in the United States. 3. Exhaust Emission Characteristics. . 3 4. 1981 Emission Control Technology. 5 A. Converters. . . 5 B. Control System. 7 8 ~. Catalyst Screening . 6. Laboratory Testing. .10 7. The Chemical Reactions 13 8. Composition of Three-Way Catalysts. 16 A. Rhodium 17 21 B. Platinum. C. Palladium 22 D. Iridium . 22 23 E. Ruthenium and Nickel. F. Cerium Oxide ..... 23 G. Search for Alternatives to Nohle Metals 24 9. Catalyst Supports . 25 A. Pellets .... 26 B. Monoliths . . 26 10. The Transient Behavior of Three-Way Catalysts 27 II. Deterioration of Three-Way Catalysts. 35 A. Thermal Effects. . . . 35 B. Phosphorus Poisoning. . . 37 C. Lead Poisoning. . . . . . · 38 D. Catalyst Poisoning by Sulfur · 40 12. The 0.4 NO,; Research Objective. · 41 13. Control of Diesel Particulate Emissions.
Author: Yiquan Xie
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Due to global lean exhaust gas and new emission regulations, exhaust after-treatment systems of diesel engines are getting more and more sophisticated and comprise a series of catalytic units. In the present work, two of these catalytic systems were studied, Diesel Oxidation Catalysts (DOC) and Selective Catalytic Reduction (SCR) catalysts. Particular attention is paid to their performance in the presence of alkali compounds when bio-diesel is utilized as the alternative fuel.Firstly, this thesis focuses on the catalytic behavior of the Diesel Oxidation Catalyst using different aging characteristics of road mileage in order to improve the efficiency of an ammonia SCR system on an after-treatment line composed by a DOC + DPF + SCR. The studied catalyst is a commercial diesel oxidation catalyst (Pt/Pd/Al2O3) provided by Continental. Hydrothermal aging under different conditions on carrots of monolith were performed. Also studied in the monolith form over the commercial DOC, the influence of the addition of different alkali metal species (K and Na) on the commercial DOC through catalytic tests performed on this structured catalyst under multicomponent (C3H6 / CO / NO / NO2) co-feeding conditions was explored. Aiming at investigating the effects of the presence of different alkali metal species on the DOC at the level of active phase, homemade bimetallic DOC is prepared and then different alkali metal species incorporated. Finally, encouraged by the evident influence of alkali compounds on DOCs, their impacts on the downstream SCR catalysts are also studied in this thesis. The studied SCR catalyst is a commercial V2O5-based catalyst provided by UMICORE company.
