Author: B. Ashok Publisher: Elsevier ISBN: 0128242280 Category : Technology & Engineering Languages : en Pages : 488
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: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Internal combustion engines, both spark ignition and Diesel, are dominant types of vehicle power sources and also provide power for other important stationary applications. Overall, these engines are a central part of power generation in modern society. However, these engines, burning hydrocarbon fuels from natural gas to gasoline and Diesel fuel, are also responsible for a great deal of pollutant emissions to the environment, especially oxides of nitrogen (NO[sub x]) and unburned hydrocarbons (UHC). In recent years, pollutant species emissions from internal combustion engines have been the object of steadily more stringent limitations from various governmental agencies. Engine designers have responded by developing engines that reduce emissions to accommodate these tighter limitations. However, as these limits become ever more stringent, the ability of engine design modifications to meet those limits must be questioned. Production of NO[sub x] in internal combustion engines is primarily due to the high temperature extended Zeldovich reaction mechanism: (1) O + N[sub 2] = NO + N; (2) N + O[sub 2] = NO + O; and (3) N + OH = NO + H. The rates of these reactions become significant when combustion temperatures reach or exceed about 2000K. This large temperature dependence, characterized by large activation energies for the rates of the reactions listed here, is a direct result of the need to break apart the tightly bonded oxygen and nitrogen molecules. The strongest bond is the triple bond in the N [triple-bond] N molecule, resulting in an activation energy of about 75 kcal/mole for Reaction (1), which is the principal cause for the large temperature dependence of the extended Zeldovich NO[sub x] mechanism. In most engines, NO[sub x] is therefore produced primarily in the high temperature combustion product gases. Using a reliable kinetic model for NO[sub x] production such as the GRI Mechanism [1] or the Miller-Bowman model [2] with hydrocarbon products at temperatures from 1500K through 2500K, the amounts of NO[sub x] produced at a given residence time in an engine can easily be computed, as shown in Figure 1. Figure 1 depicts how temperatures such as those existing in the combustion zones of heavy-duty engines would produce NO[sub x] emissions. This figure was created assuming that a fuel/air equivalence ratio [phi] of 0.65 was used to heat the combustion air. This equivalence ratio would be similar to that of a heavy-duty lean-burn spark-ignition or diesel engine. At temperatures in the neighborhood of 2000K and residence times between 1-5 milliseconds, which are typical of residence times at these temperatures in engines, the production of NO[sub x] increases dramatically. It is evident from Fig. 1 that product temperatures must remain below approximately 2100K to achieve extremely low NO[sub x] production levels in engines. This conclusion led to a combined experimental and modeling study of product gas temperatures in engine combustion and their influence on emission levels.
Author: Dragoş-George Astanei Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Faced with the current and future more and more drastic standards for pollutant emissions, the car manufacturers are permanently trying to improve the efficiency of spark ignition engines. One of the most effective applicable solutions for reducing the quantity of pollutant emissions (HC, CO, NOx) from the exhaust gases and also to reduce the fuel consumption is to operate with very lean mixture (equivalent ratio lower than 0.6). However, this operation concept is limited by the actual ignition systems that cannot assure an air/fuel mixture ignition in good conditions, in order to assure a complete, fast and repeatable combustion. The subject of this thesis consists into developing of a new ignition system based on a double spark plug, which can produce two quasi-simultaneous spark discharges with cumulated length few times higher than the sparks produced by a conventional spark plug. For ignition system validation, three different types of analysis have been considered: the analysis of the discharges electrical parameters, the plasma diagnosis using optical emission spectroscopy methods and the tests of the ignition system on two internal combustion engines with the exhaust gases analysis and engine performances determination. The tests revealed that the utilization of the double spark ignition system can assure a better stability in engine operation (especially in difficult ignition conditions such using very lean mixtures), increased engine performances for the same amount of consumed fuel and it can provide a diminution of the unburned hydrocarbons and carbon monoxide quantities from the exhaust gases, but with an increased quantity of nitrogen oxides, compared with a conventional ignition system.
Author: Anamol Pundle Publisher: ISBN: Category : Atmospheric nitrous oxide Languages : en Pages : 95
Book Description
Emissions from large-bore, spark ignition engines running on natural gas pose a serious problem, especially in non-attainment areas. These engines emit substantial amounts of oxides of nitrogen, unburned hydrocarbons and carbon monoxide. The pathways of formation of oxides of nitrogen (NOx) and formaldehyde (HCHO) have been explored in this study. This is done by using UWSI, a computer model of gas phase combustion in spark-ignition engines previously developed at the University of Washington, and through chemical reactor modeling using CHEMKIN. The UWSI model is set up and calibrated using data from a single test case. Further matching of NOx emissions for varying fuel-air equivalence ratios is also performed and the model is then used to predict NOx emission for three leanest cases beyond the range of test data. The HCHO emission from the model for each test case is examined. Several scenarios which may lead to HCHO formation in the engine are also modeled. NOx formation pathways at lean conditions in these engines are studied through chemical reactor modeling. A simplified NOx model based on the results of the chemical reactor modeling is developed and validated by comparing its results against those obtained from the UWSI code. Results obtained indicate that incomplete propagation of the flame across the cylinder is the most likely pathway to HCHO formation in these engines. Engines experiencing borderline auto-ignition may also contribute to HCHO emission, while unburned charge trapped in cracks and crevices and released late in the cycle is not indicated to have a significant effect. The Zeldovich and nitrous oxide pathways are shown to be the predominant contributors to NOx formation at lean conditions in these engines. A simplified NOx predictor based on these pathways is developed and validated against data obtained from the UWSI model.
Author: Eran Sher Publisher: Academic Press ISBN: 0080532756 Category : Technology & Engineering Languages : en Pages : 689
Book Description
This handbook is an important and valuable source for engineers and researchers in the area of internal combustion engines pollution control. It provides an excellent updated review of available knowledge in this field and furnishes essential and useful information on air pollution constituents, mechanisms of formation, control technologies, effects of engine design, effects of operation conditions, and effects of fuel formulation and additives. The text is rich in explanatory diagrams, figures and tables, and includes a considerable number of references. An important resource for engineers and researchers in the area of internal combustion engines and pollution control Presents and excellent updated review of the available knowledge in this area Written by 23 experts Provides over 700 references and more than 500 explanatory diagrams, figures and tables
Author: Richard Stone Publisher: Bloomsbury Publishing ISBN: 1137028297 Category : Technology & Engineering Languages : en Pages : 516
Book Description
Now in its fourth edition, this textbook remains the indispensable text to guide readers through automotive or mechanical engineering, both at university and beyond. Thoroughly updated, clear, comprehensive and well-illustrated, with a wealth of worked examples and problems, its combination of theory and applied practice aids in the understanding of internal combustion engines, from thermodynamics and combustion to fluid mechanics and materials science. This textbook is aimed at third year undergraduate or postgraduate students on mechanical or automotive engineering degrees. New to this Edition: - Fully updated for changes in technology in this fast-moving area - New material on direct injection spark engines, supercharging and renewable fuels - Solutions manual online for lecturers
Author: B. Ashok
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Author: Ralph David Fleming
Author: Dragoş-George Astanei
Author: Anamol Pundle
Author: Eran Sher
Author: Patia Jean McGrath
Author: Richard Stone
Author: Timothy W. Rudolph