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Viewing 1 to 30 of 35
2017-03-28
Journal Article
2017-01-0153
Dipankar Sahoo, Adam Kotrba, Tom Steiner, Greg Swift
Abstract Nearly a third of the fuel energy is wasted through the exhaust of a vehicle. An efficient waste heat recovery process will undoubtedly lead to improved fuel efficiency and reduced greenhouse gas (GHG) emissions. Currently, there are multiple waste heat recovery technologies that are being investigated in the auto industry. One innovative waste heat recovery approach uses Thermoacoustic Converter (TAC) technology. Thermoacoustics is the field of physics related to the interaction of acoustic waves (sonic power) with heat flows. As in a heat engine, the TAC produces electric power where a temperature differential exists, which can be generated with engine exhaust (hot side) and coolant (cold side). Essentially, the TAC converts exhaust waste heat into electricity in two steps: 1) the exhaust waste heat is converted to acoustic energy (mechanical) and 2) the acoustic energy is converted to electrical energy.
2017-03-28
Journal Article
2017-01-0947
Athanasios G. Konstandopoulos, Dimitrios Zarvalis, Leonidas Chasapidis, Danis Deloglou, Nickolas Vlachos, Adam Kotrba, Ginette Anderson
Abstract Evolving marine diesel emission regulations drive significant reductions of nitrogen oxide (NOx) emissions. There is, therefore, considerable interest to develop and validate Selective Catalytic Reduction (SCR) converters for marine diesel NOx emission control. Substrates in marine applications need to be robust to survive the high sulfur content of marine fuels and must offer cost and pressure drop benefits. In principle, extruded honeycomb substrates of higher cell density offer benefits on system volume and provide increased catalyst area (in direct trade-off with increased pressure drop). However higher cell densities may become more easily plugged by deposition of soot and/or sulfate particulates, on the inlet face of the monolithic converter, as well as on the channel walls and catalyst coating, eventually leading to unacceptable flow restriction or suppression of catalytic function.
2015-04-14
Technical Paper
2015-01-1026
Padmanabha Reddy Ettireddy, Adam Kotrba, Thirupathi Boningari, Panagiotis Smirniotis
Abstract The main objective of this work is to develop a low-temperature SCR catalyst for the reduction of nitrogen oxides at cold start, low-idle and low-load conditions. A series of metal oxide- incorporated beta zeolite catalysts were prepared by adopting incipient wetness technique, cation-exchange, deposition-precipitation and other synthesis techniques. The resulting catalysts were characterized and tested for reduction of NOx in a fixed bed continuous flow quartz micro-reactor using ammonia as the reductant gas. Initial catalyst formulations have been exhibited good NOx reduction activity at low-temperatures. These catalyst formulations showed a maximum NOx conversion in the temperature range of 100 - 350°C. Besides, more experiments were performed with the aim of optimizing these formulations with respect to the metal atomic ratio, preparation method, active components and supported metal type.
2014-04-01
Journal Article
2014-01-1494
Eric Hein, Adam Kotrba, Tobias Inclan, Andrew Bright
Secondary fuel injection is applied to facilitate active soot management of the particulate filter within diesel aftertreatment systems, avoiding concerns with fuel delivery via in-cylinder post-injection. System performance is dependent on the thermo-fluid interactions of the injected fuel with the exhaust stream, with the intent of having more fully vaporized fuel and a well-mixed air-fuel mixture at the inlet of the oxidation catalyst for uniform thermal distribution as it exothermically reacts. Pre-heating the fuel with a diesel vaporizer prior to its delivery into the exhaust enables improved system performance, reducing droplet sizes and mixing demands. A diesel vaporizer is applied within the exhaust of a medium duty truck application, and the response of the catalyst is characterized across a variety of conditions.
2014-04-01
Technical Paper
2014-01-1520
Padmanabha Reddy Ettireddy, Adam Kotrba, Thomas Spinks, Thirupathi Boningari, Panagiotis Smirniotis
Abstract A series of novel metal-oxide (TiO2, TiO2-SiO2)-supported Mn, Fe, Co, V, Cu and Ce catalysts were prepared by incipient wetness technique and investigated for the low-temperature selective catalytic reduction (SCR) of NOx with ammonia at industrial relevantly conditions. Among all the prepared catalysts, Cu/TiO2 showed superior de-NOx performance in the temperature range of 150-200 °C followed by Mn/TiO2 in the temperature range of 200-250 °C. The Ce/TiO2 catalyst exhibited a broad temperature window with notable de-NOx performance in the temperature regime of 250-350 °C. The phyico-chemical characterization results revealed that the activity enhancement was correlated with the properties of the support material. All the anatasetitania-supported catalysts (M/TiO2 (Hombikat)) demonstrated significantly high de-NOx performance above 150 °C.
2013-09-24
Journal Article
2013-01-2465
Adam Kotrba, Alan Brockman, Scott Martin, Alan Mikovits, Gary L. Butzke, Zack Richey, Matthew Leudeke
Catalysts and filters continue to be applied widely to meet particulate matter regulations across new and retrofit diesel engines. Soot management of the filter continues to be enhanced, including regeneration methodologies. Concerns regarding in-cylinder post-injection of fuel for active regeneration increases interests in directly injecting this fuel into the exhaust. Performance of secondary fuel injection layouts is discussed, and sensitivities on thermal uniformity are measured and analyzed, providing insight to packaging challenges and methods to characterize and improve application designs. Influences of end cone geometries, mixers, and injector mounting positions are quantified via thermal distribution at each substrate's outlet. A flow laboratory is applied for steady state characterization, repeated on an engine dynamometer, which also provides transient results across the NRTC.
2013-04-08
Technical Paper
2013-01-0520
Adam Kotrba, Timothy P. Gardner, Ling Bai, Argun Yetkin
This study investigates the passive regeneration behavior of diesel particulate filters (DPFS) with various PGM loadings under different engine operating conditions. Four wall-flow DPFs are used; one uncoated and three wash-coated with low, medium, and high PGM loadings, with and without an upstream diesel oxidation catalyst (DOC). DPFs with variable pre-soot loads are evaluated at two steady state temperatures (300°C and 400°C), as well as across three levels of transients based on the 13-mode ESC cycle. Passive regeneration rates are calculated based on pre and post soot gravimetric measurements along with accumulated soot mass rates for specified exhaust mass flow rates and temperatures. Results illustrate the effect of temperature, NO₂ content, and soot loading on passive regeneration without upstream DOCs or DPF wash coatings.
2013-04-08
Technical Paper
2013-01-1074
Guanyu Zheng, Manoj Kumar Sampath, William Alcini, Gabriel Salanta, Adam Kotrba, Bryan Axe
To meet the 2010 diesel engine emission regulations, an aftertreatment system was developed to reduce HC, CO, NOx and soot. In NOx reduction, a baseline SCR module was designed to include urea injector, mixing decomposition tube and SCR catalysts. However, it was found that the baseline decomposition tube had unacceptable urea mixing performance and severe deposit issues largely because of poor hardware design. The purpose of this article is to describe necessary development work to improve the baseline system to achieve desired mixing targets. To this end, an emissions Flow Lab and computational fluid dynamics were used as the main tools to evaluate urea mixing solutions. Given the complicated urea spray transport and limited packaging space, intensive efforts were taken to develop pre-injector pipe geometry, post-injector cone geometry, single mixer design modifications, and dual mixer design options.
2012-09-24
Technical Paper
2012-01-1960
Guanyu Zheng, Adam Kotrba, Michael Golin, Timothy Gardner, Andy Wang
The introduction of stringent EPA 2015 regulations for locomotive / marine engines and IMO 2016 Tier III marine engines initiates the need to develop large diesel engine aftertreatment systems to drastically reduce emissions such as SOx, PM, NOx, unburned HC and CO. In essence, the aftertreatment systems must satisfy a comprehensive set of performance criteria with respect to back pressure, emission reduction efficiency, mixing, urea deposits, packaging, durability, cost and others. Given multiple development objectives, a systematic approach must be adopted with top-down structure that addresses top-level technical directions, mid-level subsystem layouts, and bottom-level component designs and implementations. This paper sets the objective to provide an overview of system development philosophy, and at the same time touch specific development scenarios as illustrations.
2012-09-24
Technical Paper
2012-01-1949
Zhiguo Zhao, Guanyu Zheng, Xiaofen Shan, Adam J. Kotrba
With introductions of stringent diesel engine emission regulations, the DOC and DPF systems have become the mainstream technology to eliminate soot particles through diesel combustion under various operation conditions. Urea-based SCR has been the mainstream technical direction to reduce NOx emissions. For both technologies, low-temperature conditions or cold start conditions pose challenges to activate DOC or SCR emission-reduction performance. To address this issue, mini or full flow burner systems may be used to increase exhaust temperature to reach DOC light-off or SCR initiation temperature by combustion of diesel fuel. In essence, the burner systems incorporate a fuel injector, spray atomization, proper fuel / air mixing mechanisms, and combustion control as independent heat sources.
2012-09-24
Technical Paper
2012-01-1957
Bradley Gough, Adam Kotrba, Gabriel Salanta, Jeremy Popovich, Travis Anderson, Jason Reed, Yinyan Huang
As emissions regulations around the world become more stringent, emerging markets are seeking alternative strategies that align with local infrastructures and conditions. A Lean NOx Catalyst (LNC) is developed that achieves up to 60% NOx reduction with ULSD as its reductant and ≻95% with ethanol-based fuel reductants. Opportunities exist in countries that already have an ethanol-based fuel infrastructure, such as Brazil, improving emissions reduction penetration rates without costs and complexities of establishing urea infrastructures. The LNC performance competes with urea SCR NOx reduction, catalyst volume, reductant consumption, and cost, plus it is proven to be durable, passing stationary test cycles and adequately recovering from sulfur poisoning. Controls are developed and applied on a 7.2L engine, an inline 6-cylinder non-EGR turbo diesel.
2012-09-24
Journal Article
2012-01-1961
Guanyu Zheng, Dana Kregling, Adam Kotrba, Alan Brockman, Michael Golin
EPA 2015 Tier IV emission requirements pose significant challenges to large diesel engine aftertreatment system (EAS) development aimed at reducing exhaust emissions such as NOx and PM. An EAS has three primary subsystems, Aftertreatment hardware, controls and fluid delivery. Fluid delivery is the subsystem which supplies urea into exhaust stream to allow SCR catalytic reaction and/or periodic DOC diesel dosing to elevate exhaust temperatures for diesel particulate filter (DPF) soot regeneration. The purpose of this paper is to discuss various aspects of fluid delivery system development from flow and pressure perspective. It starts by giving an overview of the system requirements and outlining theoretical background; then discusses overall design considerations, injector and pump selection criteria, and three main injector layouts. Steady state system performance was studied for manifold layout.
2011-09-13
Technical Paper
2011-01-2198
Joshua T. Hicks, William E. Hill, Adam J. Kotrba
The Diesel Particulate Filter (DPF) is used on today's diesel vehicles to reduce the amount of soot being released into the atmosphere from diesel exhaust. The DPFs are typically wall-flow filtration devices of various extruded porous ceramic materials with more than 95% efficiency. Once the filter has loaded with soot, the DPF undergoes regeneration where the exhaust temperature is raised to burn off the soot. With the DPF being relatively new aftertreatment technology, the exhaust industry must investigate the acoustic and performance effects of the DPF when added to an exhaust system. In many applications the DPF replaces the exhaust muffler because of limited packaging space. The acoustic performance of the DPF changes with increasing soot density and exhaust backpressure. The acoustic response is measured with physical testing at multiple soot load densities. This study is part of a graduation thesis project for Kettering University[1].
2011-09-13
Technical Paper
2011-01-2200
Adam Kotrba, Ling Bai, Argun Yetkin, Robert Shotwell, Timothy Gardner
Diesel Particulate Filters (DPFs) have been successfully applied for several years to reduce Particulate Matter (PM) emissions from on-highway applications, and similar products are now also applied in off-highway markets and retrofit solutions. Most solutions are catalytically-based, necessitating minimum operating temperatures and demanding engine support strategies to reduce risks [1, 2, 3, 4, 5, 6, 7, 8]. An ignition-based thermal combustion device is applied with Cordierite and SiC filters, evaluating various DPF conditions, including effects of soot load, exhaust flow rates, catalytic coatings, and regeneration temperatures. System designs are described, including flow and temperature uniformity, as well as soot load distribution and thermal gradient response.
2011-09-13
Technical Paper
2011-01-2204
Guanyu Zheng, Timothy Gardner, Adam Kotrba, Michael Golin, Paul Majewski
EPA 2015 Tier IV emission requirements pose significant challenges to large diesel engine after treatment system development with respect to reducing exhaust emissions including HC, CO, NOx and Particulate Matter (PM). For a typical locomotive, marine or stationary generator engine with 8 to 20 cylinders and 2500 to 4500 BHP, the PM reduction target could be over 90% and NOx reduction target over 75% for a wide range of running conditions. Generally, HC, CO and PM reductions can be achieved by combining DOC, cDPF and active regeneration systems. NOx reduction can be achieved by injecting urea as an active reagent into the exhaust stream to allow NOx to react with ammonia per SCR catalysts, as the mainstream approach for on-highway truck applications.
2011-09-13
Technical Paper
2011-01-2207
Figen Lacin, Adam Kotrba, Granville Hayworth, Henry Sullivan, Marek Tatur, Jason Jacques, Dean Tomazic, Hoon Cho
Stringent global emissions legislation demands effective NOx reduction strategies, particularly for the aftertreatment, and current typical liquid urea SCR systems achieve efficiencies greater than 90% [1]. However, with such high-performing systems comes the trade-off of requiring a tank of reductant (urea water solution) to be filled regularly, usually as soon as the fuel fillings or as far as oil changes. Advantages of solid reductants, particularly ammonium carbamate, include greater ammonia densities, enabling the reductant refill interval to be extended several multiples versus a given reductant volume of urea, or diesel exhaust fluid (DEF) [2]. An additional advantage is direct gaseous ammonia dosing, enabling reductant injection at lower exhaust temperatures to widen its operational coverage achieving greater emissions reduction potential [3], as well as eliminating deposits, reducing mixing lengths, and avoiding freeze/thaw risks and investments.
2011-09-13
Technical Paper
2011-01-2199
Manoj Kumar Sampath, Guanyu Zheng, Yanping Zhang, Adam Kotrba, Michael Golin, Figen Lacin
To meet EPA Tier IV large diesel engine emission targets, intensive development efforts are necessary to achieve NOx reduction and Particulate Matter (PM) reduction targets [1]. With respect to NOx reduction, liquid urea is typically used as the reagent to react with NOx via SCR catalyst [2]. Regarding to PM reduction, additional heat is required to raise exhaust temperature to reach DPF active / passive regeneration performance window [3]. Typically the heat can be generated by external diesel burners which allow diesel liquid droplets to react directly with oxygen in the exhaust gas [4]. Alternatively the heat can be generated by catalytic burners which enable diesel vapor to react with oxygen via DOC catalyst mostly through surface reactions [5].
2011-09-13
Technical Paper
2011-01-2203
Gabriel Salanta, Adam Kotrba, John Nunan, Jason Jacques, Dan Hancu, Benjamin Winkler, Daniel Norton, Larry Lewis, Ashish Mhadeshwar
Stringent global emissions legislations demand effective NOx reduction strategies for both the engine as well as the aftertreatment. Diesel applications have previously applied Lean NOx Catalysts (LNCs) [1, 2], but their reduction efficiency and longevity have been far less than that of the competing ammonia-based SCR systems, such as urea [3]. A catalyst has been developed to significantly reduce NOx emissions, approaching 60% with ULSD and exceeding 95% with E85. Both thermal and sulfur aging are applied, as well as on-engine aging, illustrating resilient performance to accommodate necessary life requirements. A robust system is developed to introduce both ULSD from the vehicle's tank as well as E85 (up to 85% ethanol with the balance being gasoline) from a moderately sized supplemental tank, enabling extended mileage service intervals to replenish the reductant, as compared with urea, particularly when coupled with an engine-out based NOx reduction technology, such as EGR.
2011-09-13
Technical Paper
2011-01-2208
Adam J. Kotrba, Argun Yetkin, Bradley Gough, Arda Gundogan, Dan Mastbergen, Clark Paterson
Diesel Particulate Filters have been successfully applied for several years to reduce Particulate Matter (PM) emissions from on-highway applications, and similar products are now also applied in off-highway markets and retrofit solutions. As soot accumulates on the filter, backpressure increases, and eventually exhaust temperatures are elevated to burn off the soot, actively or passively. Unfortunately, in many real-world instances, some duty cycles never achieve necessary temperatures, and the ability of the engine and/or catalyst to elevate exhaust temperatures can be problematic, resulting in overloaded filters that have become clogged, necessitating service attention. An autonomous heat source is developed to eliminate such risks, applying an ignition-based combustor that leverages the current diesel fuel supply, providing necessary temperatures when needed, regardless of engine operating conditions.
2010-10-05
Technical Paper
2010-01-1938
Gabriel Salanta, Guanyu Zheng, Adam Kotrba, Rafael Rampazzo, Leonardo Bergantim
In order to satisfy tightening global emissions regulations, diesel truck manufacturers are striving to meet increasingly stringent Oxides of Nitrogen (NOx) reduction standards. The majority of heavy duty diesel trucks have integrated urea SCR NOx abatement strategies. To this end, aftertreatment systems need to be properly engineered to achieve high conversion efficiencies. A EuroV intent urea SCR system is evaluated and failed to meet NOx conversion targets with severe urea deposit formation. Systematic enhancements of the design have been performed to enable it to meet targets, including emission reduction efficiency via improved reagent mixing, evaporation, distribution, back pressure, and removing of urea deposits. Multiple urea mixers, injector mounting positions and various system layouts are developed and evaluated, including both CFD analysis and full scale laboratory tests.
2010-10-05
Technical Paper
2010-01-1946
Manoj Kumar Sampath, Guanyu Zheng, Adam Kotrba
Diesel burners recently have been used in Diesel Particulate Filter (DPF) regeneration process, in which the exhaust gas temperature is raised through the combustion process to burn off the soot particles. The feasibility of such process using the burner in large diesel applications is investigated along with a mixer and DPF. For such applications, only partial flow of the exhaust stream is fed into the burner and the resulting hot flow from combustion process is then mixed with the rest of the main stream. The amount of flow into the burner plays a vital role in overall system performance as it determines the amount of hot gas needed for Diesel Oxidation Catalyst (DOC) light-off (to facilitate DPF regeneration) and also oxygen amount needed for secondary combustion. A passive valve plate design is proposed for such flow split applications for the burner.
2010-10-05
Technical Paper
2010-01-1943
Timothy Gardner, Manoj Kumar Sampath, Guanyu Zheng, Adam Kotrba, Michael Golin
The presented work evaluates several mixer designs being considered for use in large Diesel exhaust aftertreatment systems. The mixers are placed upstream of a diesel oxidation catalyst (DOC) in the exhaust system, where a liquid hydrocarbon fuel is injected. DOC exothermic behaviour resulting from each mixer at different operating conditions is evaluated. A gas flow bench equipped with a XY-Table measurement system is used to determine gas velocity, temperature, and hydrocarbon species uniformity, as well as, pressure drop. Experimental mixer data obtained from a flow bench and an engine dynamometer are compared and discussed. The experimental methodology used in this study can be used to evaluate mixers via comprehensive testing.
2010-10-05
Technical Paper
2010-01-1941
Guanyu Zheng, Adam Fila, Adam Kotrba, Ryan Floyd
With increasing applications of urea SCR for NOx emission reduction, improving the system performance and durability has become a high priority. A typical urea SCR system includes a urea injector, injector housing, mixer, and appropriate pipe configurations to allow continuous urea injection into the exhaust stream and evaporation of urea solution into gaseous products. Continuous operation at various conditions with high NOx reduction is possible, but one problem that threatens the life and performance of these systems is urea deposit. When urea or its byproducts become deposited on the inner surfaces of the system including walls, mixers, injector housings and substrates it can create concerns of backpressure and material deteriorations. In addition, deposits as a waste of reagents can negatively affect engine operation, emissions performance and DEF economy. Urea deposit behavior is explored in terms of heat transfer, pipe geometry, injector layout and mixing mechanisms.
2009-10-06
Technical Paper
2009-01-2878
Guanyu Zheng, Manoj Sampath, Adam Kotrba
Diesel burners introduce combustion of diesel fuel to raise exhaust gas temperature to Diesel Oxidization Catalyst (DOC) light-off or Diesel Particulate Filter (DPF) regeneration conditions, thereby eliminating the need of engine measures such as post-injections. Such diesel combustion requirement nevertheless poses challenges to burner development especially in combustion control and risk mitigation of DPF material failure. In particular, burner design must satisfy good soot distribution and heat distribution at DPF front face after meeting minimum requirements of ignition, heat release, and backpressure. In burner development, Computational Fluid Dynamics (CFD) models have been developed based on commercial codes for burner thermal and flow management with capability of predicting comprehensive physical and chemical phenomena including turbulence induced mixing, fuel injection, fuel droplet transport, diesel combustion, radiation, conjugate heat transfer and etc.
2009-10-06
Technical Paper
2009-01-2879
Guanyu Zheng, Guenter Palmer, Gabriel Salanta, Adam Kotrba
2010 and future EPA regulations introduce stringent Oxides of Nitrogen (NOx) reduction targets for diesel engines. Selective Catalytic Reduction (SCR) of NOx by Urea over catalyst has become one of the main solutions to achieve these aggressive reductions. As such, urea solution is injected into the exhaust gas, evaporated and decomposed to ammonia via mixing with the hot exhaust gas before passing through an SCR catalyst. Urea mixers, in this regard, are crucial to ensure successful evaporation and mixing since its liquid state poses significant barriers, especially at low temperature conditions that incur undesired deposits. Intensive efforts have been taken toward developing such urea mixers, and multiple criteria have been derived for them, mainly including NOx reduction efficiency and uniformity. In addition, mixers must also satisfy other requirements such as low pressure drop penalty, mechanical strength, material integrity, low cost, and manufacturability.
2009-10-06
Technical Paper
2009-01-2883
Ryan Floyd, Adam Kotrba, Scott Martin, Keith Prodin
New emissions standards for oxides of nitrogen (NOx) in on-road diesel vehicles are effective in 2010, and a common approach applies urea selective catalytic reduction (SCR). Urea is injected into the exhaust and decomposes to form ammonia, which chemically reacts with NOx as it passes through an SCR catalyst. Ammonia is corrosive and negatively affects typical stainless steels used in exhaust applications, but these corrosive impacts have not yet been quantified in an exhaust system. Two unique corrosion tests are performed on a number of various stainless steel samples, illustrating such performance concerns with 409, while offering alternatives with much better performance, including cost-effective options. The method applied is described, yielding performance criteria through appearance, weight loss, and corrosion pit depth.
2009-10-06
Technical Paper
2009-01-2884
Timothy Gardner, Argun Yetkin, Robert Shotwell, Adam Kotrba, Henry Gysling, Zaki Mustafa, Joseph Holroyd
An active diesel particulate filter (DPF) regeneration system is evaluated, which applies secondary fuel injection (SFI) directly within the exhaust system upstream of a diesel oxidation catalyst (DOC). Diesel fuel is oxidized in the presence of a proprietary catalyst system, increasing exhaust gas temperatures in an efficient and controlled manner, even during low engine-out gas temperatures. The exotherms produced by secondary fuel injection (SFI) have been evaluated using two different DOC volumes and platinum catalyst loadings. DOC light-off temperatures were measured using SFI under steady-state conditions on an engine dynamometer. A ΔT method was used for the light-off temperature measurements – i.e., the minimum DOC inlet gas temperature at which the exothermic reaction increases the outlet gas temperature 20°C or greater than the inlet temperature.
2009-10-06
Journal Article
2009-01-2904
Nishit Nagar, Xiaolai He, Vikram Iyengar, Nirav Acharya, Arkadiusz Kalinowski, Adam Kotrba, Timothy Gardner, Argun Yetkin
This paper describes the joint development by Tenneco and Pi Shurlok of a complete diesel engine aftertreatment system for controlling particulate matter emissions. The system consists of a DOC, DPF, sensors, controller and an exhaust fuel injection system to allow active DPF regeneration. The mechanical components were designed for flow uniformity, low backpressure and component durability. The overall package is intended as a complete PM control system solution for OEMs, which does not require any significant additions to the OEM's engine control strategies and minimizes integration complexity. Thus, to make it easier to adapt to different engine platforms, ranging from small off-road vehicle engines to large locomotive engines, model-based control algorithms were developed in preference to map-based controls.
2009-04-20
Technical Paper
2009-01-0978
Ruth Latham, Steven Freis, Keith Olivier, Adam Kotrba, Benedikt Merker
Monolithic emission control devices typically use a support mat material to provide mechanical support, mechanical isolation, and thermal insulation for ceramic monoliths. This material is similar to a felt, but made from ceramic fibers. Non-intumescent support mat materials contain only ceramic fibers and binder compounds, while intumescent support mats also contain vermiculite; a material that expands with the application of heat. The durability of the support mat is critical to the durability of the overall emission control components. In addition to many component validation methods that evaluate the durability of the entire system methods to evaluate the response and predict the durability of the support mat itself help provide important design information. This paper summarizes challenges and artifacts in support mat testing.
2006-10-31
Technical Paper
2006-01-3567
Lawrence J. Dalimonte, Adam Kotrba, Keith Olivier, Ruth Latham
A unique validation method is proposed for mount designs of Lean NOx Traps (LNT's), in which characteristic curves of failure points as functions of thermal cycles and vibration amplitudes are generated. LNT's are one of the several new types of emissions control devices applied to Diesel Exhaust Systems, and they reduce the amount of NOx through chemical adsorption. Desulfation must occur nearly every hour, which involves raising the inlet gas temperature of the LNT to around 700°C to “burn off” sulfur from the catalyst, which otherwise would decrease its catalytic activity. This temperature is held for several minutes, and its cyclic occurrence has a negative effect on the long-term performance of the support mat, a major component of its mount design. As substrate temperatures increase, shell temperatures do as well, and thermal growth differences between the ceramic substrate and metallic shell cause the gap between them, which is filled by the support mat, to increase.
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