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Viewing 151 to 180 of 22389
Technical Paper
2014-04-01
Glenn Lucachick, Aaron Avenido, Winthrop Watts, David Kittelson, William Northrop
Abstract Diesel particulate filter (DPF) technology has proven performance and reliability. However, the addition of a DPF adds significant cost and packaging constraints leading some manufacturers to design engines that reduce particulate matter in-cylinder. Such engines utilize high fuel injection pressure, moderate exhaust gas recirculation and modified injection timing to mitigate soot formation. This study examines such an engine designed to meet US EPA Interim Tier 4 standards for off-highway applications without a DPF. The engine was operated at four steady state modes and aerosol measurements were made using a two-stage, ejector dilution system with a scanning mobility particle sizer (SMPS) equipped with a catalytic stripper (CS) to differentiate semi-volatile versus solid components in the exhaust. Gaseous emissions were measured using an FTIR analyzer and particulate matter mass emissions were estimated using SMPS data and an assumed particle density function. Though the tested engine is predicted to largely meet current US particle mass standards it has significantly higher particle number emissions compared to the Euro 6 solid particle number emissions standard.
Technical Paper
2014-04-01
Adam Dempsey, Scott Curran, John Storey, Mary Eibl, Josh Pihl, Vitaly Prikhodko, Robert Wagner, James Parks
Abstract Low temperature combustion (LTC) has been shown to yield higher brake thermal efficiencies with lower NOx and soot emissions, relative to conventional diesel combustion (CDC). However, while demonstrating low soot carbon emissions it has been shown that LTC operation does produce particulate matter whose composition appears to be much different than CDC. The particulate matter emissions from dual-fuel reactivity controlled compression ignition (RCCI) using gasoline and diesel fuel were investigated in this study. A four cylinder General Motors 1.9L ZDTH engine was modified with a port-fuel injection system while maintaining the stock direct injection fuel system. The pistons were modified for highly premixed operation and feature an open shallow bowl design. RCCI operation was carried out using a certification grade 97 research octane gasoline and a certification grade diesel fuel. To study the particulate matter emissions from RCCI operation, particle size distributions were measured with a Scanning Mobility Particle Sizer (SMPS) and total particulate concentration in the exhaust was determined using membrane filters.
Technical Paper
2014-04-01
Yang Li, Jian Xue, Kent Johnson, Thomas Durbin, Mark Villela, Liem Pham, Seyedehsan Hosseini, Zhongqing Zheng, Daniel Short, George Karavalakis, Akua Asa-Awuku, Heejung Jung, Xiaoliang Wang, David Quiros, Shaohua Hu, Tao Huai, Alberto Ayala
Abstract This study provides one of the first evaluations of the integrated particle size distribution (IPSD) method in comparison with the current gravimetric method for measuring particulate matter (PM) emissions from light-duty vehicles. The IPSD method combines particle size distributions with size dependent particle effective density to determine mass concentrations of suspended particles. The method allows for simultaneous determination of particle mass, particle surface area, and particle number concentrations. It will provide a greater understanding of PM mass emissions at low levels, and therefore has the potential to complement the current gravimetric method at low PM emission levels. Six vehicles, including three gasoline direct injected (GDI) vehicles, two port fuel injected (PFI) vehicles, and one diesel vehicle, were tested over the Federal Test Procedure (FTP) driving cycle on a light-duty chassis dynamometer. PM mass emissions were determined by the gravimetric (MGravimetric) and IPSD (MIPSD) methods.
Technical Paper
2014-04-01
Chowdhury G. Moniruzzaman, Fangqun Yu
Abstract Diesel engine emits soot which causes harm to human health, air quality and climate. It is important to understand the formation and time evolution of soot and its size distribution evolution inside engines to design strategies for emission reduction. We have developed a 0D multi-zone model for diesel fuel spray and coupled it with detailed surrogate diesel fuel chemistry and a sectional aerosol dynamics model for soot nucleation, surface growth and coagulation. Variable equivalence ratios in different zones are created by fixed fuel injection rates and variable air entrainment rates by a normal distribution function in different zones which ensures the existences of different pollutant forming zones having different equivalence ratios. Engine exit measured data of total soot mass and NOx for one operating condition are used to optimize the three model parameters. Model simulation of soot size distribution is consistent with typical measured data. Other than soot, the model also calculates the concentration of a wide range of combustion products (NOx, CO, SO2, SO3, NO, NO2, N2O, OH, HO2 etc.) which may help to study engine exhaust chemistry of pollutant reduction.
Technical Paper
2014-04-01
Yoshinori Otsuki, Kenji Takeda, Kazuhiko Haruta, Nobuhisa Mori
Abstract The particle number (PN) emission regulation has been implemented since 2011 in Europe. PN measurement procedure defined in ECE regulation No. 83 requires detecting only solid particles by eliminating volatile particles, the concentrations of which are highly influenced by dilution conditions, using a volatile particle remover (VPR). To measure PN concentration after the VPR, a particle number counter (PNC) which has detection threshold at a particle size of 23 nm is used, because most solid particles generated by automotive engines are considered to be larger than 23 nm. On the other hand, several studies have reported the existence of solid and volatile particles smaller than 23 nm in engine exhaust. This paper describes investigation into a measurement method for ultrafine PNCs with thresholds of below 23 nm and evaluation of the VPR performance for the particles in this size range. The detection efficiency of an ultrafine PNC was verified by following the ECE regulation procedure.
Technical Paper
2014-04-01
Keith Vertin, Aaron Reek
The U.S. EPA has proposed a Tier 3 rule to lower average NMOG+NOx emissions from new light duty vehicles by approximately 80% from 2017 to 2025. Early in this time period, gasoline-fueled vehicles are expected to use technologies similar to California SULEV-II/PZEV certified models currently in limited production. These late model vehicles feature engine control systems that promote rapid catalyst light-off and are designed for ultra-high catalyst conversion efficiency. To enable the use of advanced catalyst coatings and materials, the EPA is also proposing to limit the sulfur content of gasoline to an annual average of 10 ppm while optionally maintaining the current maximum cap of 80 ppm. Fuel sulfur is known to poison precious metal-based catalysts, and the impact on emissions is well understood for older technology vehicles. However, there is a lack of test data on the sensitivity and reversibility of late model vehicle emissions to sulfur. This study evaluated six late model vehicles to determine if the exhaust emissions effects caused by exposure to 80 ppm high sulfur fuel were reversible, after the vehicles were refueled with 10 ppm sulfur fuel.
Technical Paper
2014-04-01
Robert Anthony Giannelli, Ryan Stubleski, Anthony Saunders
Automobile time-resolved emissions of CO, CO2, HC, and NOx during engine and catalyst warm-up have been analyzed by fitting the emissions to the product of vehicle tractive power and a series of gaussian functions whose relative magnitudes were allowed to vary in time. From this analysis the emissions were discerned into four components : (1.) the emissions due to vehicle power demand, (2.) key-on emissions, (3.) a catalyst warm-up emissions function, and (4.) a fast idle emissions function. Both the emissions associated with the engine and the catalyst warm-up decline exponentially with time. Two additional characteristics (a.) emissions occurring during idling and (b.) emissions due to catalyst cooling during idle were observed, but not quantified. Also, a semi-empirical formula to approximate cold start emissions for light duty cars which includes the vehicle tractive power, time constants which define the emissions decrease in time, and the power demand characteristics has been developed.
Technical Paper
2014-04-01
Hu Li, Ahmad Khalfan, Gordon Andrews
A SI probe car, defined here as a normal commercial car equipped with GPS, in-vehicle FTIR tailpipe emission measurement and real time fuel consumption measurement systems, and temperature measurements, was used for measuring greenhouse gas emissions including CO2, N2O and CH4 under real world urban driving conditions. The vehicle used was a EURO4 emission compliant SI car. Two real world driving cycles/routes were designed and employed for the tests, which were located in a densely populated area and a busy major road representing a typical urban road network. Eight trips were conducted at morning rush hours, day time non-peak traffic periods and evening off peak time respectively. The aim is to investigate the impacts of traffic conditions such as road congestion, grade and turnings on fuel consumption, engine thermal efficiency and emissions. The time aligned vehicle moving parameters with fuel consumption and emission data enabled the micro-analysis of the correlations between these parameters.
Technical Paper
2014-04-01
Benjamin Reuter, Daniel Gleyzes, Markus Lienkamp
Abstract In this analysis we assess the life cycle greenhouse gas (GHG) emissions of four types of vehicles which might play a role in achieving future emission reductions: vehicles using compressed natural gas (CNG), battery electric vehicles (BEVs), mild hybrid CNG vehicles and range extended BEVs. Our analysis covers the manufacturing processes of these vehicles and their use as a city taxi in Singapore. We also consider upstream emissions from fuel and electricity production. All necessary parameters are derived from an intensive literature review and the model for calculating the life cycle emissions is presented. The influence of data uncertainties is analyzed by parameter variations within different scenarios. The calculation results are found to be quite robust: The BEV and the mild hybrid CNG vehicle similarly show very low GHG emissions within all scenarios whereas the pure CNG vehicle always ranks the worst. In an additional scenario we also assessed the influence of an improved electricity generation with lower emissions in the future.
Technical Paper
2014-04-01
Timothy H. DeFries, Michael Sabisch, Sandeep Kishan, Francisco Posada, John German, Anup Bandivadekar
Fuel economy (FE) and greenhouse gas (GHG) emissions measured via chassis testing under laboratory conditions were never intended to represent the wide range of real-world driving conditions that are experienced during a vehicle's lifetime. Comprehensive real-world information is needed to better assess US FE label adjustments, determine off-cycle credits for FE standards, and forecast real-world driving behavior, fuel consumption, and CO2 emissions. This paper explores a cost effective method to collect in-use fuel consumption data using the on-board diagnostics (OBD) data stream in light-duty vehicles (LDVs). The accuracy of fuel consumption calculated from the OBD data was analyzed in two ways. First, fuel rates calculated from standard OBD Parameter IDs (PIDs) were compared with fuel rate estimates based on enhanced PID (OEM fuel injector fuel rate) data in two different vehicles. The cumulative fuel rate derived from standard PIDs was lower than the fuel rate values obtained from injector-based data (Enhanced PID) for the tested vehicles by approximately 3% and 13%.
Technical Paper
2014-04-01
Ivan Arsie, Andrea Cricchio, Cesare Pianese, Matteo De Cesare, Walter Nesci
Abstract In the last years the automotive industry has been involved in the development and implementation of CO2 reducing concepts such as the engines downsizing, stop/start systems as well as more costly full hybrid solutions and, more recently, waste heat recovery technologies. These latter include ThermoElectric Generator (TEG), Rankine cycle and Electric Turbo Compound (ETC) that have been practically implemented on few heavy-duty application but have not been proved yet as effective and affordable solutions for the automotive industry. The paper deals with the analysis of opportunities and challenges of the Electric Turbo Compound for automotive light-duty engines. In the ETC concept the turbine-compressor shaft is connected to an electric machine, which can work either as generator or motor. In the former case the power can satisfy the vehicle electrical demand to drive the auxiliaries or stored in the batteries. In the latter case the electric motor can assist the turbine and speed up the compressor when requested.
Technical Paper
2014-04-01
Henrik Smith, Thomas Lauer, Mattias Mayer, Steven Pierson
Long-term reliability is one of the major requirements for the operation of automotive exhaust aftertreatment systems based on selective catalytic reduction (SCR). For an efficient reduction of nitrogen oxides in the SCR catalyst it is desirable that the thermolysis of the injected urea water solution (UWS) is completed within the mixing section of the exhaust system. Urea might undergo a number of secondary reactions leading to the formation of solid deposits on system walls. A deeper understanding of the mechanisms and influence factors is a basic requirement to prevent and predict undesired decomposition products. This paper outlines the mechanisms of UWS transport and deposition on a typical mixing element geometry. The conditions leading to deposit formation were investigated based on optical and temperature measurements in a box with optical access. A good correlation with the deposit location observed at the close-to-series exhaust system was found. A chemical analysis complemented the investigations.
Technical Paper
2014-04-01
Nehemiah Sabinus Alozie, David Peirce, Andreas Lindner, Wolfgang Winklmayr, Lionel Ganippa
Abstract The influence of dilution condition is known to affect the particle number size measurements of engine exhaust samples. However, it is preferable to understand how the dynamics of mixing and cooling controls the dilution scheme, rather than the dilution ratio alone as is commonly used. In this study, the effect of mixing and temperature of dilution gas on exhaust samples in a mixing-tube diluter was explored for two engine load conditions. The observed global trends of the particle number concentrations (PNC) using the mixing-tube diluter (MTD) are consistent with the findings published with different dilution systems. Relative to the two operating conditions, it was observed that, the PNC in the sub 30nm diameter were greater during the lower load operation compared to the higher load at all dilution ratios and dilution gas temperatures. Particles from the lower engine load operation were viewed to have more volatile fractions, compared to those measured under the higher load operation.
Technical Paper
2014-04-01
Stephan Stadlbauer, Harald Waschl, Luigi del Re
Abstract The emissions of modern Diesel engines, which are known to have various health effects, are beside the drivers torque demands and low fuel consumptions one of the most challenging issues for combustion and after treatment control. To comply with legal requirements, emission control for heavy duty engines is not feasible without additional hardware, usually consisting of a Diesel oxidation catalyst (DOC), a Diesel particulate filter (DPF) and a selective catalytic reduction (SCR) system. In contrast to other NOx reduction systems, e.g. lean NOx traps, the SCR system requires an additional ingredient, namely ammonia (NH3), to reduce the NOx emissions to non harmful components. Consequently, the correct amount of NH3 dosing in the SCR catalyst is one of the critical components to reach high conversion rates and avoid ammonia slip. Against this background and in contrast to existing proposals in which the NH3 dosing is often calculated based on a NOx emission sensor, this work presents a strategy to adopt the set point estimation of the NH3 dosing, based on a virtual NOx sensor extended by a virtual DOC model.
Technical Paper
2014-04-01
Yi Liu, Wei Chen, Matthew Henrichsen, Arvind Harinath
Abstract Diesel emission aftertreatment system is usually designed to meet stringent packaging constraints, rendering a difficult situation to achieve perfect flow distribution inside the catalytic unit. The non-uniform flow pattern leads to a mal-distribution of flow velocity, temperature, and gas species in catalyst unit. Some catalysts are exposed to harsh working environment, while the rest catalysts are underutilized. This lowers the efficiency of overall catalyst unit and thus requires an oversized system to meet emission requirements. The flow mal-distribution also accelerates the uneven catalyst degradation, lowering the system durability. Hence, a quantitative description of packaging impact on catalyst performance is critical to assess the system efficiency and durability. In the present work, a mapping method is developed to combine catalyst performance with computational fluid dynamics (CFD) simulation. This method is used to analyze the performance and robustness of a SCR aftertreatment system using a series of packaging designs.
Technical Paper
2014-04-01
Zhiming Gao, Tim J. LaClair, C. Stuart Daw, David E. Smith, Oscar Franzese
We present simulated fuel economy and emissions of city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but tailpipe (post-aftertreatment) emissions are affected by complex interactions between engine load and the transient catalyst temperatures, and the emissions results were found to depend significantly on motor size and details of each drive cycle.
Technical Paper
2014-04-01
Mengting Yu, Vemuri Balakotaiah, Dan Luss
Abstract The particulate matter (PM) emitted by a diesel engine is collected and then combusted in a diesel particulate filter (DPF). A sudden decrease of the engine load of DPF undergoing regeneration, referred to as a drop to idle (DTI), may create a transient temperature peak much higher than under stationary feed conditions. This transient temperature rise may cause local melting or cracking of the filter. We report here the dependence of the maximum temperature following a DTI on the DPF properties and its dependence on the operating conditions. The simulated impact of changes in DPF properties on peak regeneration temperature following a DTI is qualitatively similar to their impact under stationary operation. (1) The maximum DTI temperature and temperature gradient can be decreased by preheating the DPF before igniting the PM. (2) A decrease of the inlet gas temperature and/or a two-step regeneration can decrease the maximum DTI regeneration temperature. (3) The peak DTI regeneration temperature decreases upon an increase of either the filter wall thickness or the solid volumetric heat capacity. (4) When the DPF heat transfer is under axial heat Peclet number (Eqn. (4)) control, the peak temperature decreases upon an increase of the solid conductivity and/or a decrease of the filter aspect ratio (L/D). (5) The peak DTI temperature is a nonlinear function of the cell density. (6) The dependence of the maximum temperature gradient on the maximum regeneration temperature is not always monotonic.
Technical Paper
2014-04-01
Stephan Adelberg, Friedemann Schrade, Peter Eckert, Lutz Kraemer
Abstract The development and calibration of exhaust aftertreatment (EAT) systems for the most diverse applications of diesel powertrain concepts requires EAT models, capable of performing concept analysis as well as control and OBD system development and calibration. On the concept side, the choice of an application-specific EAT layout from a wide technology selection is driven by a number of requirements and constraints. These include statutory requirements regarding emissions of criteria pollutants and greenhouse gases (GHG), technical constraints such as engine-out emissions and packaging, as well as economic parameters such as fuel consumption, and EAT system and system development costs. Fast and efficient execution of the analysis and multi-criteria system optimization can be done by integrating the detailed EAT models into a total system simulation. On the control / OBD side, the software design, testing and calibration, of both EAT and engine, is efficiently supported by the integrated simulation approach.
Technical Paper
2014-04-01
Wanyu Sun, Shufen Wang, Shanheng Yan, Lei Guo, Yuanjing Hou
Abstract Selective catalytic reduction (SCR) has become one of the primary technologies to reduce internal combustion engine (ICE) emission. The installation angle of urea injector plays an important role during the SCR process. The urea injector is often vertically mounted to the exhaust pipe for on road heavy duty truck because of its good performance and general packaging convenience, and this type of installation has been the focus of previous research. However, due to certain packaging constraints or responsiveness considerations, the injector is installed with an inclined acute angle to the exhaust pipe under some circumstance. To evaluate the underlying benefits and risks of this type of installation angle, a computational fluid dynamic (CFD) model based on the Renolds averaged Navier-Stokes (RANS) solver from AVL Fire is used to simulate the injection process of urea for an acute-angled 3-hole injector, through which, the urea spray's formation and motion, wallfilm accumulation and NH3 distribution uniformity characteristics are studied.
Technical Paper
2014-04-01
Sandeep Viswanathan, Stephen Sakai, David Rothamer
Abstract The Diesel Exhaust Filtration Analysis System (DEFA) developed at the University of Wisconsin Madison was modified to perform fundamental filtration experiments using particulate matter (PM) generated by a spark-ignition direct-injection (SIDI) engine fueled with gasoline. The newly modified system, termed the Exhaust Filtration Analysis (EFA) system, enables small-scale fundamental studies of wall-flow filtration processes. A scanning mobility particle sizer (SMPS) was used to characterize running conditions with unique particle size distributions (PSDs). The SMPS and an engine exhaust particle sizer (EEPS) were used to simultaneously measure the PSD downstream of the EFA and the real-time particulate emissions from the SIDI engine, to determine the evolution of filtration efficiency during filter loading. Corrections were developed for each running condition to compare measured PSDs between the EEPS and the SMPS in the raw, as well as, filtered exhaust stream. Background losses in the EFA system (without a filter sample) were quantified for each operating condition.
Technical Paper
2014-04-01
Xiaobo Song, Jeffrey Naber, John H. Johnson
Abstract Selective catalytic reduction (SCR) systems are in use on heavy duty diesel engines for NOx control. An SCR NOx reduction efficiency of higher than 95% is required to meet the proposed increasingly stringent NOx emission standards and the 2014-2018 fuel consumption regulations. The complex engine exhaust conditions including the nonuniformity of temperature, flow, and maldistribution of NH3 present at the catalyst inlet need to be considered for improved performance of the SCR system. These factors cause the SCR to underperform negatively impacting the NOx reduction efficiency as well as the NH3 slip. In this study, the effects of the nonuniformity of temperature, flow velocity and maldistribution of NH3 on the SCR performance were investigated using 1-dimensional (1D) model simulations for a Cu-zeolite SCR. The model was previously calibrated and validated to reactor and steady-state and transient engine experimental data. The SCR engine experimental measurements collected from a transient cycle were used as the baseline for the simulations.
Technical Paper
2014-04-01
Kiran C. Premchand, Harsha Surenahalli, John H. Johnson
Abstract A numerical model to simulate the filtration and oxidation of PM as well as the oxidation of NO, CO and HC in a CPF was developed in reference [1]. The model consists of parameters related to filtration and oxidation of PM and oxidation of NO, CO and HC. One of the goals of this paper is to use the model to determine the PM and gaseous species kinetics for ULSD, B10 and B20 fuels using data from passive oxidation and active regeneration engine experimental studies. A calibration procedure to identify the PM cake and wall filtration parameters and kinetic parameters for the PM oxidation and NO, CO and HC oxidation was developed. The procedure was then used with the passive oxidation [2] and active regeneration [3] engine data. The tests were conducted on a 2007 Cummins ISL engine with a DOC and CPF aftertreatment system. The simulation results show good agreement with the experimental CPF pressure drop, PM mass retained measurements and the outlet NO, NO2, CO and HC concentrations.
Technical Paper
2014-04-01
Peter Bonsack, Ross Ryskamp, Marc Besch, Daniel Carder, Mridul Gautam, John Nuszkowski
Abstract Due to tightening emission legislations, both within the US and Europe, including concerns regarding greenhouse gases, next-generation combustion strategies for internal combustion diesel engines that simultaneously reduce exhaust emissions while improving thermal efficiency have drawn increasing attention during recent years. In-cylinder combustion temperature plays a critical role in the formation of pollutants as well as in thermal efficiency of the propulsion system. One way to minimize both soot and NOx emissions is to limit the in-cylinder temperature during the combustion process by means of high levels of dilution via exhaust gas recirculation (EGR) combined with flexible fuel injection strategies. However, fuel chemistry plays a significant role in the ignition delay; hence, influencing the overall combustion characteristics and the resulting emissions. Therefore, the Fuels for Advanced Combustion Engines (FACE) Working Group of the Coordinating Research Council (CRC) specified and formulated a matrix of nine test fuels for advanced combustion engines based on the variation of three properties: cetane number, aromatic content, and 90 percent distillation temperature.
Technical Paper
2014-04-01
Gary D. Neely, Darius Mehta, Jayant Sarlashkar
The diesel engine can be an effective solution to meet future greenhouse gas and fuel economy standards, especially for larger segment vehicles. However, a key challenge facing the diesel is the upcoming LEV III and Tier 3 emission standards which will require significant reductions in hydrocarbon (HC) and oxides of nitrogen (NOx) emissions. The challenge stems from the fact that diesel exhaust temperatures are much lower than gasoline engines, so the time required to achieve effective emissions control after a cold-start with typical aftertreatment devices is considerably longer. To address this challenge, a novel diesel cold-start emission control strategy was investigated on a 2L class diesel engine. This strategy combines several technologies to reduce tailpipe HC and NOx emissions before the start of the second hill of the FTP75. The technologies include both engine tuning and aftertreatment changes. The benefits of the engine tuning changes were presented in detail in a previous publication.
Technical Paper
2014-04-01
Damien Aubagnac-Karkar, Jean-Baptiste Michel, Olivier Colin, Ludovic Noël, Nasser Darabiha
Abstract In this paper, a sectional soot model coupled to a tabulated combustion model is compared with measurements from an experimental engine database. The sectional soot model, based on the work of Vervisch-Klakjic (Ph.D. thesis, Ecole Centrale Paris, Paris, 2011) and Netzell et al. (P. Combust. Inst., 31(1):667-674, 2007), has been implemented into IFPC3D (Bohbot et al., Oil Gas Sci Technol, 64(3):309-335, 2009), a 3D RANS solver. It enables a complex modeling of soot particles evolution, in a 3D Diesel simulation. Five distinct source terms are applied to each soot section at any time and any location of the flow. The inputs of the soot model are provided by a tabulated combustion model derived from the Engine Approximated Diffusion Flame (EADF) one (Michel and Colin, Int. J. Engine Res., 2013) and specifically modified to include the minor species required by the soot model. An experimental database has been built, using both commercial Diesel fuel and the computed surrogate (30% alpha-methylnaphthalene and 70% decane in volume) to compare result between the Diesel fuel and the surrogate and to validate the models against the experiment.
Technical Paper
2014-04-01
Xu Chen, Ashok Kumar, David Klippstein, Randy Stafford, Changsheng Su, Ying Yuan, James Zokoe, Paul McGinn
Abstract Experimental evaluation of soot trapping and oxidation behaviors of various diesel particulate filters (DPF) has been traditionally hampered by several experimental difficulties, such as the deposition of soot particles with well-characterized and consistent properties, and the tracking of the soot oxidation rate in real time. In the present study, an integrated bench flow-reactor system with a soot generator has been developed and its capabilities were demonstrated with regards to: Consistently and controllably loading soot on DPF samples; Monitoring the exhaust gas composition by FTIR, including quantification of the soot oxidation rate using CO and CO2; Measuring soot oxidation characteristics of various DPF samples. Soot particles were produced from a laminar propane co-flow diffusion flame. The production rate of particulate matter (PM) of the soot generator, which is tunable by adjusting the air to fuel ratio of the propane flame, can be set within a range from tens of mg to 400 mg per hour.
Technical Paper
2014-04-01
Hidemasa Iwata, Athanasios Konstandopoulos, Kazuki Nakamura, Kazutake Ogyu, Kazushige Ohno
Abstract Exhaust Gas Recirculation (EGR) is an effective method to reduce Nitrogen Oxide emissions. In recent years the trend of increasing EGR rate in-cylinders is an integral part of most improvements in combustion technology developments. The object of this work is to study the influence of EGR rate on the physical and chemical properties of soot particles. Soot from several operating points of a diesel engine run were collected on a high temperature filters. The pressure drop behavior during the soot loading was monitored then the soot permeability was calculated. Afterwards, the soot primary size was calculated from the obtained data and it showed good correspondence to the actual measurement. It is confirmed that all the soot primary sizes were around 22 nm in diameter. In contrast, the soot aggregate sizes and the soot concentrations were found to increase with increasing EGR rate. Subsequently, Oxidation tests were conducted to evaluate the reactivity of the soot. It is observed that soot oxidation temperatures varied in the range of 500 to 600 degree Celsius (C).
Technical Paper
2014-04-01
Tomohiro Minagawa, Daiji Nagaoka, Hiroyuki Yuza, Teruo Nakada, Takeyuki Kamimoto
Abstract The filtration efficiency of a DPF drops when it suffers a failure such as melting and cracks during regeneration. And then, on-board diagnostics (OBD) device has become needed worldwide to detect a DPF failure. In the development of an OBD soot sensor, evaluation of the sensor demands a portable instrument which can measure the soot concentration for on-board and in-field use. Some of the emission regulations require the in-field emission measurements under normal in-use operation of a vehicle. This study is intended to develop a high sensitivity and high response portable smoke meter for on-board soot measurements and a reference to OBD soot sensors under development. The smoke meter accommodates a 650 nm laser diode, and its principle is based on light extinction in high soot concentration range and backward light scattering for low soot concentration measurement. Raw exhaust sample flows through a thermo-controlled optical tube at a flow rate of 3 liter/min, and the total system unit weighs only 16 kg.
Technical Paper
2014-04-01
John May, Dirk Bosteels, Cecile Favre
From 1 September 2014 new car types in the EU must meet ‘Euro 6’ emissions requirements. The ‘New European Driving Cycle’ (NEDC) is currently the main test for this, but the European Commission intends to also introduce PEMS (Portable Emissions Measurement Systems)-based procedures to ensure that emissions are well controlled in real use. ‘Random Cycles’ have also been considered and remain a possible option for ‘real world’ particle number measurement. At the same time, the UN Working Party on Pollution and Energy (GRPE) has developed the new Worldwide harmonized Light vehicles Test Procedure (WLTP) that is expected to be adopted in the EU in the near future. To identify and understand the differences in emissions that may arise between these various methodologies, AECC has conducted some initial tests on two modern light-duty vehicles. Chassis dynamometer emissions tests were conducted over the NEDC, the Common Artemis suite of test cycles (CADC), the new Worldwide Light-duty Test Cycle (WLTC - the test cycle for WLTP) and a set of cycles produced by a Random Cycle Generator based on ‘short trip’ segments from the EU database used to construct WLTC.
Technical Paper
2014-04-01
Lokanath Mohanta, Suresh Iyer, Partha Mishra, David Klinikowski
Abstract This paper illustrates a method to determine the experimental uncertainties in the measurement of tailpipe emissions of carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons, and particulates of medium-, and heavy-duty vehicles when tested on a heavy-duty chassis dynamometer and full-scale dilution tunnel. Tests are performed for different chassis dynamometer driving cycles intended to simulate a wide range of operating conditions. Vehicle exhaust is diluted in the dilution tunnel by mixing with conditioned air. Samples are drawn through probes for raw exhaust, diluted exhaust and particulates and measured using laboratory grade emission analyzers and a microbalance. At the end of a driving cycle, results are reported for the above emissions in grams/mile for raw continuous, dilute continuous, dilute bag, and particulate measurements. An analytical method is developed in the present study to estimate the measurement uncertainties in emissions for a test cycle, due to the buildup of measurement uncertainties as they propagate through the system.
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