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Viewing 181 to 210 of 22386
Technical Paper
2014-04-01
Ryan Foley, Jeffrey Naber, John H. Johnson, Leigh Rogoski
Abstract Optimizing the performance of the aftertreatment system used on heavy duty diesel engines requires a thorough understanding of the operational characteristics of the individual components. Within this, understanding the performance of the catalyzed particulate filter (CPF), and the development of an accurate CPF model, requires knowledge of the particulate matter (PM) distribution throughout the substrate. Experimental measurements of the PM distribution provide the detailed interactions of PM loading, passive oxidation, and active regeneration. Recently, a terahertz wave scanner has been developed that can non-destructively measure the three dimensional (3D) PM distribution. To enable quantitative comparisons of the PM distributions collected under different operational conditions, it is beneficial if the results can be discussed in terms of the axial, radial, and angular directions. This paper focuses on the development of an analysis method and metrics that quantitatively describe the PM distribution in the aforementioned directions.
Technical Paper
2014-04-01
Susanna Paz, Rosa Delgado, David Riba
Abstract Currently, regulations on vehicle evaporative emissions only focus on the sum of Total Hydrocarbons (THC) without taking into account either the detailed hydrocarbon composition nor other chemicals besides hydrocarbons emitted from gasoline evaporation. As a consequence, this composition, also known as speciation, is not always noted and is even more unknown when biofuels such as ethanol are introduced in the market. Furthermore, these regulations do not differentiate the source of these emissions in the vehicle. The programme described in this paper is designed to investigate the influence of the addition of ethanol to gasoline on evaporative emissions. It has tried to go one step ahead of these directives obtaining more detailed characterization of these evaporative emissions. The programme has enabled a list of compounds (methanol, ethanol, aldehydes, ketones and hydrocarbons) to be determined in evaporative emissions among different ethanol-gasoline fuels (E0, E5-S, E10 and E85), applied to Euro 4 and Flexifuel vehicles by three chromatographic methods based on California Air Resources Board (CARB).
Technical Paper
2014-04-01
Nehemiah Sabinus Alozie, David Peirce, Lionel Ganippa
Abstract When assessing particulate emissions, diesel engine exhausts are usually diluted to suit the design limitations of the measurement devices. Particle number concentrations (PNC) are known to be sensitive to dilution conditions and must be considered when evaluating results. Laboratories employ various experimental techniques to dilute exhaust samples before measurements. The majority of measurement systems use air as dilution a gas, some employ filtered exhaust gas in a closed loop, while others employ nitrogen, where prevention of oxidation reaction is required. In this work, the effect of using air and nitrogen as dilution gases on the PNCs from diesel engine exhausts has been investigated. Our approach explored the use of carbon dioxide (CO2) concentration ratios in diluted and raw exhaust samples, evaluated by non-dispersive infrared (NDIR) analysers to determine dilution conditions of the measured sample. The comparative effect of using nitrogen and air as dilution gases was then assessed.
Technical Paper
2014-04-01
Jan Czerwinski, Yan Zimmerli, Andreas Mayer, Norbert Heeb, Jacques Lemaire, Giovanni D'Urbano
Abstract The combined exhaust gas aftertreatment systems (DPF+SCR) are the most efficient way and the best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NOx). SCR (selective catalytic reduction) is regarded as the most efficient deNOx-system, diesel particle filters are most efficient for soot abatement. Today, several suppliers offer combined systems for retrofitting of HD vehicles. Quality standards for those quite complex systems and especially for retrofit systems are needed to enable decisions of several authorities and to estimate the potentials of improvements of the air quality in highly populated agglomerations. The present paper informs about the VERTdePN *) quality test procedures, which were developed in an international network project with the same name 2007-2011 (VERT … Verification of Emission Reduction Technologies; dePN … decontamination, disposal of PM / NP and of NOx). Some interesting results of research on the engine dynamometer from the last test period 2011-2013 are given as a complement of the already published results.
Technical Paper
2014-04-01
Michael Robinson, Z. Gerald Liu, Michael Olson, James Schauer
Light absorbing components of aerosols, often called black carbon (BC), are emitted from combustion sources and are believed to play a considerable role in direct atmospheric radiative forcing by a number of climate scientists. In addition, it has been shown that BC is associated with adverse health effects in a number of epidemiological studies. Although the optical properties (both absorbing and scattering) of combustion aerosols are needed in order to accurately assess the impact of emissions on radiative forcing, many models use radiative properties of diesel particulate matter that were determined over two decades ago. In response to concerns of the human health impacts of particulate matter (PM), regulatory bodies around the world have significantly tightened PM emission limits for diesel engines. These requirements have resulted in considerable changes in engine technology requiring updated BC measurements from modern engines equipped with aftertreatment systems. In this study, a variety of common ambient monitoring techniques were used to characterize the light absorbing properties of diesel aerosol.
Technical Paper
2014-04-01
Shaohua Hu, Suiyun Zhang, Satya Sardar, Shiyan Chen, Inna Dzhema, Shiou-Mei Huang, David Quiros, Huaiwei Sun, Christopher Laroo, L. James Sanchez, James Watson, M.-C. Oliver Chang, Tao Huai, Alberto Ayala
Abstract The California Air Resources Board (CARB) adopted the Low Emission Vehicle (LEV) III regulations in January 2012, which lowered the particulate matter (PM) emissions standards for light-duty vehicles (LDVs) from 10 milligrams per mile (10 mg/mile) to 3 mg/mile beginning with model year (MY) 2017 and 1 mg/mile beginning with MY 2025. To confirm the ability to measure PM emissions below 1 mg/mile, a total of 23 LDVs (MY pre-2004 to 2009) were tested at CARB's Haagen-Smit Laboratory (HSL) (10 LDVs) and the United States Environmental Protection Agency's (US EPA) National Vehicle and Fuel Emissions Laboratory (NVEFL) (13 LDVs) using the federal test procedure (FTP) drive schedule. One LDV with PM emissions ranging from 0.6 - 0.8 mg/mile was tested at three CARB HSL test cells to investigate intra-lab and inter-lab variability. Reference, trip, and tunnel filter blanks were collected as part of routine quality control (QC) procedures. Reference and trip blanks showed the well-documented filter weighing and handling process had negligible impact on final test values.
Technical Paper
2014-04-01
Teresa Donateo, Fabio Ingrosso, Daniele Bruno, Domenico Laforgia
Abstract This investigation describes the results of an experimental and numerical research project aimed at comparing mileage and CO2 emissions from two different commercial versions of Daimler AG Smart ForTwo car: conventional (gasoline) and electric (ED). The investigation includes numerical simulations with the AVL CRUISE software package and on-board acquisitions. A data acquisition system has been designed for this purpose and assembled on board of the Smart ED. The system is composed by a GPS antenna with USB interface, two current transducers, a NI-DAQ device and a netbook computer with a LabView-VI. This system provided on-board information about driving cycle and current flows, gathered simultaneously by GPS, transducers and NI-DAQ. The system was also used to evaluate the losses of energy during the recharge of the electric car. The two cars have been tested over a wide range of driving conditions related to different routes, traffic conditions and use of on-board accessories (i.e.
Technical Paper
2014-04-01
Fernando Ortenzi, Giovanni Pede, Ennio Rossi
Abstract The adoption of composed (hybrid) lead acid battery-supercapacitor (SC) storage systems is able to improve performances (availability, durability, range) of an electric microcar. As a matter of fact, the supercapacitors extend the operation time not only by improving the energy efficiency (thanks to a higher contribution of regenerative braking), but also by reducing the power down caused by voltage drop at higher discharge rates. The integration of battery with supercapacitors requires careful analysis and calculation of the relationship between battery peak power and size of the SC bank, needed to have a balanced composition of the hybrid storage system. For this purpose, the optimization process, summarized here, is based on the combination of a conventional lead-acid battery and a commercial SC, with the vehicle running the ECE15 driving cycle. A Matlab/Simulink model has been developed in order to characterize the benefits of the adoption of such hybrid storage system and experimental tests have been used to calibrate it.
Technical Paper
2014-04-01
Anne Marie Lewis, Gregory Keoleian, Jarod Kelly
Abstract As lightweight materials and advanced combustion engines are being used in both conventional and electrified vehicles with diverse fuels, it is necessary to evaluate the individual and combined impact of these technologies to reduce energy and greenhouse gas (GHG) emissions. This work uses life cycle assessment (LCA) to evaluate the total energy and GHG emissions for baseline and lightweight internal combustion vehicles (ICVs), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) when they are operated with baseline and advanced gasoline and ethanol engines. Lightweight vehicle models are evaluated with primary body-in-white (BIW) mass reductions using aluminum and advanced/high strength steel (A/HSS) and secondary mass reductions that include powertrain re-sizing. Advanced engine/fuel strategies are included in the vehicle models with fuel economy maps developed from single cylinder engine models. Results show that while the ethanol engine has the highest efficiency and therefore, highest MPGe, the increased energy required to produce ethanol outweighs this benefit.
Technical Paper
2014-04-01
Tingting Zhang, Xiaomin Xie, Zhen Huang
Abstract The aim of this study is to evaluate the land requirement, energy consumption and GHG (greenhouse gases) emissions of microalgal biodiesel (M-BD) and Jatropha curcas seeds (J-BD) based biodiesel from the perspective of life cycle assessment (LCA). Mass and energy balance was used through the whole LCA calculation for each process. Two types of biodiesel (100% biodiesel: BD100, and 20% blends of biodiesel: BD20) were assumed to be combusted in the suitable diesel engine. Displacement method was adopted to measure the co-products credits. The results showed that the land requirement of producing 1 kg biodiesel from microalgae was about 1/31 of that from Jatropha curcas seeds. The well to pump (WTP) stage for microalgal biodiesel had higher fossil energy requirement but lower petroleum energy consumption and GHG emissions compared to Jatropha curcas and conventional diesel (CD). The WTP energy efficiency for J-BD100 and M-BD 100 were 26% and 17.4%, respectively. The feedstock growing stage of microalgae and Jatropha curcas was found to be the most fossil energy-intensive stage.
Technical Paper
2014-04-01
Atsushi Mizutani
Abstract This paper describes the development of high efficiency and compact bumper recycling equipment for facilitating bumper recycling globally. Various equipment to remove paint coat from bumper has been developed since 90s', using mechanical, physical or chemical method. However, it is difficult to promote bumper recycling without realizing cost effective overall system from paint coat removal to pelletizing. Our company jointly developed method of mechanically removing paint coat and has committed to bumper recycling in the form of outsourcing since 2000. In 2010, a dedicated plant for recycling bumpers was launched on the premises of our Oppama Assembly Plant in Japan. In the future, promoting bumper recycling at other overseas assembly plants is necessary as vehicle production will expand globally. Having more compact and cost effective recycling system compared to the one at the Oppama plant is required since the scale of the system including bumper crushing, paint coat removal, and pelletizing has to match processing capacity at these plants rather than equipping large one like Oppama's.
Technical Paper
2014-04-01
Alessandro Libriani
Abstract Synthetic rubber is used in automobiles for various applications. Tires, seals, gaskets, engine mounts, wiring cables and under the hood hoses are just a few examples. Synthetic rubber is a man-made material that uses several components as polymers, resins, carbon black, fillers, vulcanizing agents, reinforcement agents. It is a material that heavily depends on oil for its constituency, therefore it has a large carbon footprint. This study proposes the use of natural filler for automotive seals using synthetic rubber in order to reduce the impact on the environment. Calcium carbonate is the most preponderant choice as material filler because it is abundant in nature and is mined extensively. Calcium carbonate is also present in several structures in nature. Oyster shells have a great amount of it as well as egg shells. Egg shells also constitute an environmental bio-hazard when discarded in a landfill due to the organic inner membrane. The use of discarded egg shells is limited to few applications, mainly pharmaceutical.
Technical Paper
2014-04-01
Claire Boland, Robb DeKleine, Aditi Moorthy, Gregory Keoleian, Hyung Chul Kim, Ellen Lee, Timothy J. Wallington
Abstract Automakers have the opportunity to utilize bio-based composite materials to lightweight cars while replacing conventional, nonrenewable resource materials. In this study, Life Cycle Assessment (LCA) is used to understand the potential benefits and tradeoffs associated with the implementation of bio-based composite materials in automotive component production. This cradle-to-grave approach quantifies the fiber and resin production as well as material processing, use, and end of life for both a conventional glass-reinforced polypropylene component as well as a cellulose-reinforced polypropylene component. The comparison is calculated for an exterior component on a high performance vehicle. The life cycle primary energy consumption and global warming potential (GWP) are evaluated. Reduced GWP associated with the alternative component are due to the use of biomass as process energy and carbon sequestration, in addition to the alternative material component's lightweighting effect.
Technical Paper
2014-04-01
Tae-il Yoo, Hanhee Park, Gubae Kang, Seongyeop Lim
Abstract Development of eco-friendly vehicles have risen in importance due to fossil fuel depletion and the strengthened globalized emission control regulatory requirements. A lot of automotive companies have already developed and launched various types of eco-friendly vehicles which include hybrid vehicles (HEVs) or electric vehicles (EVs) to reduce fuel consumption. To maximize fuel economy Hyundai-Kia Motor Company has introduced eco-friendly vehicles which have downsized or eliminated vibration damping components such as a torque converter. Comparing with Internal Combustion Engine(ICE) powered vehicles, one issue of the electric motor propulsion system with minimized vibration damping components is NVH (Noise, Vibration and Harshness). The NVH problem is caused by output torque fluctuation of the motor system, resulting in the degradation of ride comfort and drivability. Therefore, accomplishing both fuel economy and good NVH performance has become a significantly challenging task in eco-friendly vehicles.
Technical Paper
2014-04-01
Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco, Francesco Catapano
Abstract The use of methane as supplement to liquid fuel is one of the solution proposed for the reduction of the internal combustion engine pollutant emissions. Its intrinsic properties as the high knocking resistance and the low carbon content makes methane the most promising clean fuel. The dual fuel combustion mode allows improving the methane combustion acting mainly on the methane slow burning velocity and allowing lean burn combustion mode. An experimental investigation was carried out to study the methane-gasoline dual fuel combustion. Methane was injected in combustion chamber (DI fuel) while gasoline was injected in the intake manifold (PFI fuel). The measurements were carried out in an optically accessible small single-cylinder four-stroke engine. It was equipped with the cylinder head of a commercial 250 cc motorcycles engine representative of the most popular two-wheel vehicles in Europe. UV-visible spectroscopy measurements were performed to analyze the combustion process with high spatial and temporal resolution.
Technical Paper
2014-04-01
Valentin Soloiu, Alejandro Rivero-Castillo, Martin Muinos, Marvin Duggan, Spencer Harp, Wallace Peavy, Sven Wolter, Brian Vlcek
Abstract This study presents the combustion and emissions characteristics of Reactivity Controlled Combustion Ignition (RCCI) produced by early port fuel injection (PFI) of low reactivity n-butanol (normal butanol) coupled with in cylinder direct injection (DI) of cottonseed biodiesel in a diesel engine. The combustion and emissions characteristics were investigated at 5.5 bars IMEP at 1400 RPM. The baseline was taken from the combustion and emissions of ULSD #2 which had an ignition delay of 13° CAD or 1.5ms. The PFI of n-butanol and DI of cottonseed biodiesel strategy showed a shorter ignition delay of 12° CAD or 1.45ms, because of the higher CN of biodiesel. The combustion proceeded first by the ignition of the pilot (cottonseed biodiesel) BTDC that produced a premixed combustion phase, followed by the ignition of n-butanol that produced a second spike in heat release at 2° CAD ATDC. The addition of n-butanol into the cycle reduced the compression and peak temperature by 100K and resulted in 35% NOx and 90% soot reduction.
Technical Paper
2014-04-01
Hassan Ali Khairallah, Umit Koylu
Abstract During the past decade, considerable efforts have been made to introduce alternative fuels for use in conventional diesel and gasoline engines. There is significant interest in adding hydrogen to a diesel engine to reduce emissions and improve efficiency. With the rapid increase in computational capabilities, computational fluid dynamics (CFD) codes have become essential tools for the design, control, and optimization of dual fuel engines. In the present study, a reduced chemical kinetics mechanism, consisting of 52 reactions and 29 chemical species for n-heptane fuel combustion, was incorporated with detailed chemical kinetics consisting of 29 reactions for hydrogen including additional nitrogen oxidation. This reaction mechanism was coupled with a 3D CFD model based on AVL FIRE software to investigate the performance and emission characteristics of a diesel engine with low amounts of hydrogen addition. The model was validated by the experimental results and then employed to examine important parameters that have significant effects on the engine performance.
Technical Paper
2014-04-01
Debabrata Barik, Murugan Sivalingam
Abstract The present study was aimed to run the diesel engine only with two renewable fuels in a dual fuel mode. The karanja methyl ester (KME) derived from karanja oil was used as an injected fuel, and the biogas obtained from the anaerobic digestion of pongamia pinnata (Karanja) de-oiled cakes, was used as a secondary fuel in a single cylinder, four stroke, air cooled, direct injection (DI) diesel engine. Four different flow rates of biogas, viz., 0.3 kg/h, 0.6 kg/h, 0.9 kg/h and 1.2 kg/h were inducted along with the air in the suction of the engine. The results of the experiment were compared with those of diesel and KME operations. Biogas inducted at a flow rate of 0.9 kg/h was found to be the best among all the flow rates, in terms of the performance and emission of the engine. The dual fuel operation showed a higher BSEC than that of diesel operation at full load. In dual fuel operation, about 22% of KME replacement was possible with the biogas flow rate of 0.9 kg/h at full load.
Technical Paper
2014-04-01
Nicolas Dronniou, Julian Kashdan, Bertrand Lecointe, Kyle Sauve, Dominique Soleri
Abstract Dual-fuel combustion strategies combining a premixed charge of natural gas and a pilot injection of diesel fuel offer the potential to reduce CO2 emissions as a result of the high Hydrogen/Carbon (H/C) ratio of methane gas. Moreover, the high octane number of methane means that dual-fuel combustion strategies can be employed on compression ignition engines without the need to vary the engine compression ratio, thereby significantly reducing the cost of engine hardware modifications. The aim of this investigation is to explore the fundamental combustion phenomena occurring when methane is ignited with a pilot injection of diesel fuel. Experiments were performed on a single-cylinder optical research engine which is typical of modern, light-duty diesel engines. A high-speed digital camera recorded time-resolved combustion luminosity and an intensified CCD camera was used for single-cycle OH*chemiluminescence imaging. Experiments were performed for a wide range of equivalence ratios of the premixed charge.
Technical Paper
2014-04-01
Jongik Jeon, Hyongman Seo, Kangwon Lee, Soonhyung Kwon, Kisong Bae
Abstract This paper describes how to meet LEVII ULEV70 emission standards and minimize fuel consumption with the combined NOx after-treatment (LNT+SCR) system for diesel vehicles. Through analysis of LNT's functionality and characteristics in a LNT+SCR combined after-treatment system, allowed a new control strategy to be established, different from the existing LNT-only system. In the 200°C or higher condition where SCR can provide the most stable NOx conversion efficiency, rich regeneration of LNT was optimized to minimize LNT deterioration and fuel consumption. Optimized mapping between rapid heat up strategy and raw NOx reduction maximized LNT's NOx conversion efficiency during the intervals when it is not possible for SCR to purify NOx This study used bench aged catalysts which were equivalent to 150K full useful life. During the Highway (HFET) driving cycle when the SCR conversion rate is generally high, fuel economy was improved by minimization DeNOx in LNT and improvement of the engine combustion efficiency.
Technical Paper
2014-04-01
S. Hirose, H. Yamamoto, H. Suenobu, H. Sakamoto, F. Katsube, P. Busch, A. Martin, R. Kai, C. D. Vogt
Today the Ammonia Selective Catalytic Reduction (SCR) system with good NOx conversion is the emission technology of choice for diesel engines globally. High NOx conversion SCR systems combined with optimized engine calibration not only address the stringent NOx emission limits which have been introduced or are being considered for later this decade, but also reduce CO2 emissions required by government regulations and the increase in fuel economy required by end-users. Reducing the packaging envelope of today's SCR systems, while retaining or improving NOx conversion and pressure drop, is a key customer demand. High SCR loadings ensure high NOx conversion at very low temperatures. To meet this performance requirement, a High Porosity Substrate which minimizes the pressure drop impact, was introduced in SAE Paper 2012-01-1079 [1], [2], [3]. The High Porosity Substrate with an equivalent catalyst amount demonstrated a pressure drop reduction in SCR substrate against the baseline conventional substrate.
Technical Paper
2014-04-01
Xiangyu Feng, Yunshan Ge, Jianwei Tan, Jiaqiang Li, Yao Zhang, Chenglei Yu
Abstract The NOx conversion efficiency of vanadium-based SCR catalyst is lower under low temperature. Utilizing an exhaust analyzer, the effects of electrically heated catalyst on the performance of vanadium-based SCR catalyst under low temperature was studied on the engine test bench. The inlet temperature of SCR catalyst without the electrically heated catalyst were in the range of 150°C∼270°C under various steady engine modes, and the NSR (Normalized Stoichiometric Ratio) was set as 0.4,0.6,0.8,1.0. The results showed that under the space velocity of 20000h−1, with the application of the electrically heated catalyst, the inlet temperature of SCR increased about 19.9°C on average and the NOx conversion efficiency improved about 8.0%. The NOx conversion efficiency increased 1.7%∼8.6% at the temperatures of 150°C∼174°C, and 1.0%∼15.9% at the temperatures of 186°C∼270°C. The experiment space velocity properties indicated that with the electrically heated catalyst, the inlet temperature increase and the increasing rate of the NOx conversion efficiency both decreased with the increasing space velocity.
Technical Paper
2014-04-01
Takahiro Umeno, Masaya Hanzawa, Yoshiyuki Hayashi, Masao Hori
Abstract In this study several NOx storage materials have been investigated to see their NOx storage properties. And sulfur release properties of these materials have been also investigated. Based on these findings, new LNT catalyst was developed. In this new LNT catalyst Barium is supported on one basic material, and Strontium is coated in the whole catalyst with high dispersion. And it shows higher NOx storage performance against conventional LNT one even though 10g/L of sulfur was introduced to the catalysts. According to analysis results of new LNT catalyst after sulfur poisoning, it was found that sulfur was mainly adsorbed on Strontium selectively, and then it formed sulfate compound as SrSO4. On the other hand, another sulfate compounds could be hardly observed. And regarding Barium on basic material some analysis measurement said that it has not only better NOx storage function, but also better sulfur release function. The assumption why new LNT catalyst has high sulfur resistance is that Strontium works like scavenger effect against sulfur, therefore it enables to keep higher NOx storage performance by Barium even if it contains much sulfur amount in the catalyst.
Technical Paper
2014-04-01
Mojghan Naseri, Raymond Conway, Howard Hess, Ceren Aydin, Sougato Chatterjee
Abstract Selective Catalytic Reduction (SCR) systems have been demonstrated as effective solutions for controlling NOx emissions from Heavy Duty diesel engines. Future HD diesel engines are being designed for higher engine out NOx to improve fuel economy, which will require increasingly higher NOx conversion to meet emission regulations. For future aftertreatment designs, advanced technologies such as SCR coated on filter (SCRF®) and SCR coated on high porous flow through substrates can be utilized to achieve high NOx conversion. In this work, different options were evaluated for achieving high NOx conversion. First, high performance NOx control catalysts were designed by using SCRF unit followed by additional SCR on high porosity substrates. Second, different control strategies were evaluated to understand the effect of reductant dosing strategy and thermal management on NOx conversion. Tests were carried out on a HD engine under transient test cycles. The results indicated that NOx conversion can be significantly improved using the proposed design of SCRF component along with SCR on high porosity substrates.
Technical Paper
2014-04-01
Matthieu Lecompte, Stephane Raux, Arnaud Frobert
Abstract The selective catalytic reduction (SCR) based on urea water solution (UWS) is an effective way to reduce nitrogen oxides (NOx) emitted by engines. The high potential offered by this solution makes it a promising way to meet the future stringent exhaust gas standards (Euro6 and Tier2 Bin5). UWS is injected into the exhaust upstream of an SCR catalyst. The catalyst works efficiently and durably if the spray is completely vaporized and thoroughly mixed with the exhaust gases before entering. Ensuring complete vaporization and optimum mixture distribution in the exhaust line is challenging, especially for compact exhaust lines. Numerous parameters affect the degree of mixing: urea injection pressure and spray angle, internal flow field (fluid dynamics), injector location …. In order to quantify the mixture quality (vaporization, homogeneity) upstream of the SCR catalyst, it is proposed to employ non intrusive optical diagnostics techniques such as laser induced fluorescence (LIF).
Technical Paper
2014-04-01
Keld Johansen, Henrik Bentzer, Arkady Kustov, Kenneth Larsen, Ton V.W. Janssens, Rasmus G. Barfod
Abstract Today, the DPF and SCR catalysts are combined sequentially in diesel exhaust systems. However, such sequential system configuration has several drawbacks: 1) large volume; 2) insufficient temperature for the SCR catalyst during cold start when DPF is placed in front of SCR; and 3) unfavorable conditions for passive soot regeneration if SCR is placed upstream of the DPF. The problems can potentially be solved by integrating the SCR catalyst into the particulate filter as one multifunctional unit. The study indicates that SCRonDPF based on Cu-zeolite type as SCR material can achieve the NOx conversion levels close to flow-through SCR catalysts for LDV (Light Duty Vehicles) using forced regenerations. Forced soot regeneration solves potential sulfur poisoning. For HDV (Heavy Duty Vehicles) applications with full managed passive soot regenerations, integration of V-based SCR formulations on DPF represents an attractive solution due to high sulfur resistance accompanied by low-temperature fuel economy.
Technical Paper
2014-04-01
Jean Balland, Michael Parmentier, Julien Schmitt
Similar to single-brick SCR architectures, the multi-brick SCR systems described in this paper require urea injection control software that meets the NOx conversion performance target while maintaining the tailpipe NH3 slip below a given threshold, under all driving conditions. The SCR architectures containing a close-coupled SCRoF and underfloor SCR are temperature-wise more favorable than the under-floor location and lead to significant improvement of the global NOx conversion, compared to a single-brick system. But in order to maximize the benefit of close-coupling, the urea injection control must maximize the NH3 stored in the SCRoF. The under-floor SCR catalyst can be used as an NH3 slip buffer, lowering the risk of NH3 slip at the tailpipe with some benefit on the global NOx conversion of the system. With this approach, the urea injection strategy has a limited control on the NH3 coverage of the under-floor SCR catalyst. To take more advantage of the under-floor SCR catalyst for improving the NOx conversion, the NH3 coverage of the under-floor SCR must be taken into account, and therefore a combined control of both catalysts is required.
Technical Paper
2014-04-01
Jason D. Pless, Mojghan Naseri, Wassim Klink, Glen Spreitzer, Sougato Chatterjee, Penelope Markatou
Selective Catalytic Reduction (SCR) catalysts have been demonstrated as an effective solution for controlling NOx emissions from diesel engines. There is a drive to reduce the overall packaging volume of the aftertreatment system for these applications. In addition, more active SCR catalysts will be needed as the applications become more challenging: e.g. lower temperatures and higher engine out NOx, for fuel consumption improvements. One approach to meet the challenges of reduced volume and/or higher NOx reduction is to increase the active site density of the SCR catalyst by coating higher amount of SCR catalyst on high porosity substrates (HPS). This approach could enable the reduction of the overall packaging volume while maintaining similar NOx conversion as compared to 2010/2013 systems, or improve the NOx reduction performance for equivalent volume and NH3 slip. In this work, systems consisting of SCR coated on high porosity substrates were evaluated in comparison to standard substrate based SCR systems used in typical 2010 applications.
Technical Paper
2014-04-01
Douglas Lee Ummel, Kenneth Price
Non-road Tier 4 Final emissions standards offer opportunities for engines to be certified with DOC + SCR aftertreatment systems (ATS), where particulate matter (PM) emissions will be controlled by engine measures. These non-filter systems will not experience high thermal conditions common for filter regeneration and, therefore, will not have the secondary benefit of thermal events removing sulfur from the DOC and SCR aftertreatment. An experimental program was conducted on DOC + SCR systems in which the DOC was selected for the anticipated NO2 and sulfur management requirements of a fixed volume of 3 SCR types (vanadia, copper and iron). Each system was optimized to NOx conversion levels of 90%+ on NRTC cycles then exposed to accelerated sulfur poisoning and various cycles of increasing temperature after each poisoning to observe the performance recovery of the system. Specific sulfur management strategies are defined, depending on technology. Though each system has its own unique sensitivity to sulfur and conditions where it recovers, all SCR systems are capable of sustaining 90%+ NOx conversion levels.
Technical Paper
2014-04-01
Homayoun Ahari, Michael Zammit, Luis Cattani, Jason Jacques, Thomas Pauly
Abstract To meet TierII/LEVII emissions standards, light duty diesel (LDD) vehicles require high conversion efficiencies from the Aftertreatment Systems (ATS) for the removal of both Hydrocarbon (HC) and Nitrogen Oxide (NOx) species. The most populous configuration for LDD ATS have the Selective Catalytic Reduction (SCR) catalyst positioned on the vehicle behind the close coupled Diesel Oxidation Catalyst (DOC) and Catalyzed Diesel Particulate Filter (CDPF). This SCR position may require active heating measures which rely on the DOC/CDPF to provide heat through the combustion of HC and CO in the exhaust. Although DOCs are always impacted by their aging conditions, some aging conditions are shown to be both reversible and irreversible. Under continuous, high speed and high mileage conditions such as experienced in a modified Standard Road Cycle (SRC) or as it is better known, the High Speed Cycle (HSC), it is shown that the DOC's activity can deteriorate initially but significantly recover over repeated FTP-75 test cycles on fully aged catalysts.
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