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Viewing 91 to 120 of 22756
2015-04-14
Technical Paper
2015-01-1075
Muhammad Ahmar Zuber, Wan Mohd Faizal Wan Mahmood, Zambri Harun, Zulkhairi Zainol Abidin, Antonino La Rocca, Paul Shayler, Fabrizio Bonatesta
In-cylinder soot particle size and its distribution are of interest to engine designers and researchers as they influence the soot emitted from exhaust tailpipes as well as the soot in oil.  The focus of this present study is to analyse changes in soot particle size along predicted pathlines as they pass through different in-cylinder combustion histories.  The prediction of a soot particle pathline, size and how it is transported in the cylinder of a direct injection diesel engine was performed using post-processed in-cylinder combustion data from Kiva-3v CFD simulations with a series of Matlab routines.  Soot particles were assumed massless and only soot surface growth and oxidation processes were considered in calculating the sizes.  3500 locations at 8° Crank Angle (CA) ATDC were selected inside the engine cylinder at the beginning of the pathline and size calculation.  
2015-04-14
Technical Paper
2015-01-1070
Hanzhengnan Yu, Yong Guo, Donghai Li, Xingyu Liang, Ge-Qun Shu, Yuesen Wang, Xiangxiang Wang, Lihui Dong
Impingement of injected fuel spray against the cylinder liner (wall wetting) is one of the main obstacles that must be overcome in order for early injection Homogeneous Charge Compression Ignition (EI HCCI) combustion to become an advanced alternative to conventional engine combustion systems. In the strategies to reduce or prevent wall wetting explored in the past, limiting the spray cone angle was proved to be a useful approach. This paper is presented to study the effect of the spray cone angle on the mixture formation, particularly the region near the cylinder wall, and CO/Soot emissions of an early injection HCCI diesel engine. Three-dimensional modeling was performed in AVL FIRE code, which includes the spray/wall impingement model and film vaporization model for both gas- and liquid-phase transport processes. The calculation grid was divided into three regions which were defined as the combustion chamber region, the wall wetting region, and other regions.
2015-04-14
Technical Paper
2015-01-1079
Jan Czerwinski, Pierre Comte, Adrian Wichser, Andreas Mayer, Jacques Lemaire
The invisible nanoparticles (NP)*) from combustion processes penetrate easily into the human body through the respiratory and olfactory ways and cary numerous harmful health effects potentials. NP count concentrations are limited in EU for Diesel passenger cars since 2013 and for gasoline cars with direct injection (GDI) since 2014. The limit for GDI was temporary extended to 6 x 1012 #/km. Nuclei of metals as well as organics are suspected to significantly contribute especially to the ultrafine particle size fractions, and thus to the particle number concentration. In the project GasOMeP (Gasoline Organic & Metal Particulates) metal-nanoparticles (including sub 20nm) from gasoline cars are investigated for different engine technologies. In the present paper some results of investigations of nanoparticles from four gasoline cars - an older one with MPI and three never with DI - are represented. The measurements were performed at vehicle tailpipe and in CVS-tunnel.
2015-04-14
Technical Paper
2015-01-1080
Eduardo J. Barrientos, Matti M. Maricq, Andre L. Boehman, James E. Anderson
Biodiesel has been proven to have a strong impact on the oxidative reactivity of diesel soot. The fatty acid methyl esters, of which biodiesel is comprised, exhibit a more complex ignition chemistry than normal alkanes of equivalent carbon number. Studies have shown a clear dependence of soot reactivity on fuel oxygenate molecular structure, suggesting that the unique oxidation behavior of esters may be a governing factor of the enhanced soot oxidation behavior presented by biodiesel. A study and analysis of the relation of biodiesel chemical structures to the resulting soot characteristics and soot oxidative reactivity was conducted. Soot samples generated from the combustion of various methyl esters, alkanes, biodiesel and diesel fuels in laminar co-flow diffusion flames were analyzed to evaluate the impact of fuel-bound oxygen in fatty acid esters on soot oxidation behavior.
2015-04-14
Technical Paper
2015-01-0827
Yan Zhang, Macklini Dalla Nora, Hua Zhao
Controlled Auto Ignition (CAI), also known as Homogeneous Charge Compression Ignition (HCCI), is one of the most promising combustion technologies to reduce the fuel consumption and NOx emissions. In order to extend its currently limited operational range and meet the demand of whole vehicle driving cycles, the authors have transplanted it back in a 2-stroke engine with poppet valve train, where the output torque is doubled compared to that of 4-stroke engines. Due to the air short-circuiting issue on 2-stroke engines, the lean boost operation has been implemented with CAI combustion under a speed range from 800rpm to 3000rpm and an IMEP range from 1.1bar to 7.8bar. In this work, to further extend the operational range, ethanol-gasoline blends, E85 were tested with 2-stroke lean boost operation. The results show that CAI high load knocking limit is extended because of the charge cooling effect and slower burning rate of ethanol.
2015-04-14
Technical Paper
2015-01-1009
Cameron W. Tanner, Kenneth Twiggs, Tinghong Tao, David Bronfenbrenner, Yoshiaki Matsuzono, Shinichiro Otsuka, Yukio Suehiro, Hiroshi Koyama
The EPA Tier 3 standard set in 2014 calls for a 65% reduction in combined NOx and NMOG pollutants from 86 to 30 mg/mile between 2017 and 2025 to improve air quality. In 2012, the EPA set a target to double fleet average fuel economy by 2025 as compared to 2010. The European Union has enacted and is in the process of phasing in regulations with similar objectives. For gasoline-powered cars and trucks, approximately 75% of emissions over a standard regulatory test like FTP-75 are released in the first 40 s after cold-start. Reductions in cold-start emissions will be part of the strategy to meet these challenging new regulations. The techniques that are proven to speed catalyst light-off to lower cold-start emissions are to move the converter upstream (close-coupling), to reduce the heat capacity of the converter, and to utilize catalysts that are active at low temperatures.
2015-04-14
Technical Paper
2015-01-1008
Vitaly Y. Prikhodko, Josh A. Pihl, Todd J. Toops, John F. Thomas, James E. Parks, Brian H. West
Ethanol is a very effective reductant for nitrogen oxides (NOX) over silver/alumina (Ag/Al2O3) catalysts in lean exhaust environments. With the widespread availability of ethanol/gasoline-blended fuel in the U.S., lean gasoline engines equipped with Ag/Al2O3 catalysts have the potential to deliver higher fuel economy than stoichiometric gasoline engines and to increase biofuel utilization while meeting exhaust emissions regulations. In this work a pre-commercial 2 wt% Ag/Al2O3 catalyst was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine for the selective catalytic reduction (SCR) of NOX with ethanol/gasoline blends. The ethanol/gasoline blends were delivered via in-pipe injection upstream of the Ag/Al2O3 catalyst with the engine operating under lean conditions. A number of engine conditions were chosen to provide a range of temperatures and space velocities for evaluation of catalyst performance.
2015-04-14
Technical Paper
2015-01-1076
Tak W. Chan
Octane number is an indication of the antiknocking strength of gasoline and it is strongly linked to engine performance which has direct influence on vehicle black carbon (BC) and ultrafine particle emissions. In the past, additives such as tetra-ethyl lead (TEL) were used as antiknocking fuel additives, but were phased out due to environmental and human health issues. More recently, other options such as butane, aromatics, and different oxygenates (i.e., alcohols and ethers) have been used to increase the knock resistance of gasoline. Ethanol is one of the most commonly used alcohols to increase the antiknocking resistance of gasoline. When used in internal combustion engines, ethanol-gasoline fuel provides a number of direct advantages such as antiknocking, reduced CO emissions, high Reid vapor pressure, and charge air cooling.
2015-04-14
Technical Paper
2015-01-1074
Michael A. Robinson, Chris Cremeens, Z. Gerald Liu
Diesel engines have been identified as contributing to more than half of the transport sectors black carbon (BC) emissions in the US. This large contribution to atmospheric BC concentrations has raised concern about source specific emission rates. The European Union has recently implemented more stringent particulate regulations in the form of particle number via the Particle Measurement Programme (PMP) methodology. The PMP method counts the non-volatile fraction of particulate matter (PM) above 23 nm and below 2.5 µm via a condensation particle counter. This study evaluates a surrogate black carbon method which uses the PMP particle count method with a correlation factor of 2x1012 #/mg. The transient capable Magee Scientific Aethalometer (AE-33) 880 nm wavelength channel was used to determine the BC fraction. PMP particle count displayed linear correlation with the cycle averaged AE-33 BC measurement (R2 = 0.96), agreeing with previously published BC-PN correlation factors.
2015-04-14
Technical Paper
2015-01-1072
Aron D. Butler, Rafal A. Sobotowski, George J. Hoffman, Paul Machiele
The EPAct/V2/E-89 fuel effects program collected emissions data for 27 test fuels using a fleet of 15 high-sales cars and light trucks from the 2008 model year (all with port fuel injection). The fuel matrix design covered a range of T50, T90, ethanol, vapor pressure, and total aromatics based on market gasoline survey data. Emission measurements were made over the LA92 cycle at 75°F. The resulting emissions database of 956 tests includes particulate matter (PM) mass for each test in addition to regulated and unregulated gaseous pollutants. PM Index was calculated for the test fuels using the method described by Aikawa, et al, in SAE paper number 2010-01-2115. Good correlation of PM mass emissions with PM Index was found for most vehicles in the EPAct/V2/E-89 database. When test fuels were grouped by ethanol level (E0, E10, E15, E20), a reinforcing interaction of ethanol on PM Index was observed.
2015-04-14
Technical Paper
2015-01-1078
Zhigang Chai, Fujun Zhang, Bolan Liu, Ying Huang, Xiaowei Ai
It was found that biodiesel has a great potential to reduce the nitrogen oxides (NOx) and soot simultaneously in low-temperature combustion (LTC) mode. The objective of this study was to investigate the combustion and emission characteristics of 20% biodiesel blend diesel fuel (B20) under several EGR for LTC application. An experimental investigation of B20 was conducted on a four-stroke direct injection diesel engine at 2000rpm and 25% load condition. The EGR rate was adjusted from 10% to 65%, and the injection pressure was tuned from 100MPa to 140MPa. The result showed that soot increased with the promotion of EGR rate under 50%, while between 50% and 65% EGR rate region the soot decreased dramatically and NOx emission performed at almost zero level, meanwhile the ignition delay was prolonged by more than 40%. Compare to the conventional diesel, the soot emission of B20 emerged decrease tendency at the same EGR rate condition.
2015-04-14
Journal Article
2015-01-0810
Hao-ye Liu, Zhi Wang, Jian-Xin Wang
Wide Distillation Fuel (WDF) refers to the fuels with a distillation range from initial boiling point (IBP) of gasoline to final boiling point (FBP) of diesel. Polyoxymethylene dimethyl ethers (PODEn) have high oxygen content and cetane number, are promising green additive to diesel fuel. In this paper, WDF was prepared by blending diesel and gasoline at ratio of 50/50, by volume; the mass distribution of oligomers in the PODEn product was 0.27% of n=1, 2.553% of n=2, 88.9% of n=3 and 8.46% of n=4, by volume. Neat diesel fuel (D), WDF, WDF (90%)-PODEn (10%) (P10), WDF (80%)-PODEn (20%) (P20) and WDF (70%)-PODEn (30%) (P30) were tested in a light-duty single-cylinder diesel engine, combustion characteristic, fuel consumption and exhaust emissions were measured. The results showed that: adding PODEn into WDF reduces the ignition delay of blend fuels, so fuel-air mixing is not sufficient compared neat WDF.
2015-04-14
Journal Article
2015-01-0809
Joonsik Hwang, Yongjin Jung, Choongsik Bae
The effect of biodiesel produced from waste cooking oil (WCO) on the soot particles of a compression ignition diesel engine was experimentally investigated and compared with conventional diesel fuel. The indicated mean effective pressure of approximately 0.75 MPa was tested under an engine speed of 1200 revolutions per minute. The fuels were injected at an injection timing of -5 crank angle degree after top dead center with injection pressures of 80 MPa. Detailed characteristics of particulate matters were analyzed in terms of transmission electron microscopy (TEM), thermogravimetric analysis and elemental analysis. For the work, soot aggregates were collected with a thermophoretic sampling device installed in the exhaust pipe of the engine. High-resolution TEM images revealed that the WCO biodiesel soot was composed of smaller primary particle than diesel soot. The mean primary particle diameter was measured as 19.9 nm for WCO biodiesel and 23.7 nm for diesel, respectively.
2015-04-14
Journal Article
2015-01-0957
George Karavalakis, Daniel Short, Diep Vu, Robert Russell, Akua Asa-Awuku, Thomas Durbin
Biofuels have been the subject of significant political and scientific attention, owing to concerns about climate change, global energy security, and the decline of world oil resources that is aggravated by the continuous increase of the demand for fossil fuels. Among the different oxygenated biofuels being used globally today, ethanol is the most widely employed, although geographically its usage is somewhat restricted to U.S., Brazil, and Canada. An alternative bio-alcohol for use in spark ignition (SI) engines without modification is butanol or butyl alcohol (C4H9OH). Butanol offers a number of advantages over ethanol for transportation use. Butanol is less corrosive than ethanol, has a higher energy content than ethanol, and more closely resembles gasoline. This study evaluated the potential emissions impacts of different alcohol blends on a fleet of modern gasoline vehicles. Testing was conducted on a fleet of 9 vehicles over different combinations of 10 fuel blends.
2015-04-14
Technical Paper
2015-01-0914
Ehsan Tootoonchi, Gerald Micklow
Abstract Understanding the physics and chemistry involved in diesel combustion, with its transient effects and the inhomogeneity of spray combustion is quite challenging. Great insight into the physics of the problem can be obtained when an in-cylinder computational analysis is used in conjunction with either an experimental program or through published experimental data. The main area to be investigated to obtain good combustion begins with the fuel injection process and the mean diameter of the fuel particle, injection pressure, drag coefficient, rate shaping etc. must be defined correctly. The increased NOx production and reduced power output found in engines running biodiesel in comparison to petrodiesel is believed to be related to the different fuel characteristics in comparison to petroleum based diesel. The fuel spray for biodiesel penetrates farther into the cylinder with a smaller cone angle. Also the fuel properties between biodiesel and petrodiesel are markedly different.
2015-04-14
Technical Paper
2015-01-1020
Joel Michelin, Philippe Nappez, Frederic Guilbaud, Christof Hinterberger, Eric Ottaviani, Catherine Gauthier, Philippe Maire, Thierry Couturier
Abstract Future Diesel emission standards for passenger cars, light and medium duty vehicles, require the combination of a more efficient NOx reduction performance, a significant reduction of fuel consumption along with the opportunity to reduce the complexity and the package requirements to facilitate it. Recent activities on catalytic products allows for the SCR active compounds to move from the ceramic substrate located in the underbody to the DPF substrate already located in a close coupled position to achieve the benefit of the highest temperature. This newly developed SCR-coated DPF has massively improved the potential of NOX reduction. As published in the SAE-2014-0132 “advanced compact mixer: BlueBox” [1] it is crucial to inject Adblue®/DEF with a very high mixing performance level.
2015-04-14
Technical Paper
2015-01-1030
Ashok Kumar, Krishna Kamasamudram, Neal Currier, Aleksey Yezerets
Abstract The high global warming potential of nitrous oxide (N2O) led to its inclusion in the list of regulated greenhouse gas (GHG) pollutants [1, 2]. The mitigation of N2O on aftertreatment catalysts was shown to be ineffective as its formation and decomposition temperatures do not overlap. Therefore, the root causes for N2O formation were investigated to enable the catalyst architectures and controls development for minimizing its formation. In a typical heavy-duty diesel exhaust aftertreatment system based on selective catalytic reduction of NOx by ammonia derived from urea (SCR), the main contributors to tailpipe N2O are expected to be the undesired reaction between NOx and NH3 over SCR catalyst and NH3 slip in to ammonia slip catalyst (ASC), part of which gets oxidized to N2O.
2015-04-14
Technical Paper
2015-01-1024
Hisao Haga, Hiroyuki Kojima, Naoko Fukushi, Naoki Ohya, Takuya Mito
Abstract A diesel engine is possible solution for carbon dioxide (CO2) reduction from automobiles. However, it is necessary for a diesel engine vehicle to reduce nitrogen oxide (NOx) emission. Therefore, this research focused on a Urea-selective catalytic reduction (urea-SCR) system as an after-treatment system to convert NOx and proposes the control method of the urea-SCR system based on the output of an ammonia (NH3) sensor. By maximizing NH3 storage rate of the SCR, conversion performance is maximized. To maximize the NH3 storage rate, an NH3 sensor is installed downstream of the SCR. The amount of urea-solution is controlled to keep NH3 slip detected by the sensor. Thus, the NH3 storage amount in the SCR or the SCRF (SCR on filter) can be maximized. The estimation and the control of NH3 storage amount is also used to cause NH3 slip immediately. NH3 storage capacity changes with catalyst temperature. In a transient state, temperature distribution occurs in the SCR catalyst.
2015-04-14
Technical Paper
2015-01-1038
Jinbiao Ning, Fengjun Yan
Abstract Using urea-based Selected Catalytic Reduction (SCR) systems is an effective way in diesel engine after-treatment systems to meet increasingly stringent emission regulations. The amount of urea injection is critical to achieve high NOx reduction efficiency and low ammonia slip and overdosing or under-dosing of urea injection need to be avoided. One of the difficulties in urea injection amount control lies in the accurate measurement/estimation of the urea injection mass. To effectively address this issue, this paper defined a correction factor for under-dosing or overdosing detection and correction and proposed two methods to identify the correction factor. The first method is based on urea pump model and line pressure. Through frequency analysis, the relation between the urea pump speed and power spectrum characteristics of the line pressure by using FFT method was revealed.
2015-04-14
Technical Paper
2015-01-1045
Stephan Stadlbauer, Harald Waschl, Luigi del Re
Abstract The focus in the development of modern exhaust after treatment systems, like the Diesel Oxidation Catalyst (DOC), the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR), is to increase on one hand the oxidation rates of Carbon monoxide (CO), HC (Hydro Carbons) and NO (Nitrogen Oxide) and on the other hand the reduction rates of Particulate Matter (PM) and the NOx emissions to fulfill the more and more restricting requirements of the exhaust emission legislation. The simplest, practical most relevant way to obtain such a dosing strategy of a SCR system is the use of a nonlinear map, which has to be determined by extensive calibration efforts. This feedforward action has the advantage of not requiring a downstream NOx sensor and can achieve high conversion efficiency under steady-state operating conditions for nominal systems.
2015-04-14
Technical Paper
2015-01-1060
Yangdongfang Yang, Gyubaek Cho, Christopher Rutland
Abstract The SCR Filter simultaneously reduces NOx and Particle Matter (PM) in the exhaust and is considered an effective way to meet emission regulations. By combining the function of a Diesel Particulate Filtration (DPF) and a Selective Catalytic Reduction (SCR), the SCR Filter reduces the complexity and cost of aftertreatment systems in diesel vehicles. Moreover, it provides an effective reaction surface and potentially reduces backpressure by combining two devices into one. However, unlike traditional flow through type SCR, the deNOx reactions in the SCR Filter can be affected by the particulate filtration and regeneration process. Additionally, soot oxidation can be affected by the deNOx process. A 1-D kinetic model for integrated DPF and NH3-SCR system over Cu-zeolite catalysts was developed and validated with experimental data in previous work[1].
2015-04-14
Technical Paper
2015-01-1059
Harsha Shankar Surenahalli, Gordon Parker, John H. Johnson
Abstract Diesel Oxidation Catalysts (DOC) are used on heavy duty diesel engine applications and experience large internal temperature variations from 150 to 600°C. The DOC oxidizes the CO and HC in the exhaust to CO2 and H2O and oxidizes NO to NO2. The oxidation reactions are functions of its internal temperatures. Hence, accurate estimation of internal temperatures is important both for onboard diagnostic and aftertreatment closed loop control strategies. This paper focuses on the development of a reduced order model and an Extended Kalman Filter (EKF) state estimator for a DOC. The reduced order model simulation results are compared to experimental data. This is important since the reduced order model is used in the EKF estimator to predict the CO, NO, NO2 and HC concentrations in the DOC and at the outlet. The estimator was exercised using transient drive cycle engine data. The closed loop EKF improves the temperature estimate inside the DOC compared to the open loop estimator.
2015-04-14
Technical Paper
2015-01-1058
Osami Yamamoto, Tatsuya Okayama, Zhiwei Zhang, John Tolsma
Abstract Catalyst simulation, which can analyze the complicated reaction pathway of exhaust gas purifications and identify the rate-determining step, is an essential tool in the development of catalyst materials. This requires an elementary reaction model which describes the detailed processes, i.e. adsorption, decomposition, and others. In our previous work, the elementary reaction model on Pt/CeO2 catalyst was constructed. In this study, we focused on extending the Zeolite catalyst and including the gas diffusivity through the catalyst layer. The reaction rate of a Zeolite catalyst was expressed by an Arrhenius equation, and the elementary reaction model was composed of 17 reactions. Each Arrhenius parameter was optimized by the catalytic activity measurements. The constructed model was validated with NOx conversion in cyclic experiments which were repeated with Lean phase (NOx adsorption) and Rich phase (NOx reduction).
2015-04-14
Technical Paper
2015-01-1068
Rong Yang, Diming Lou, Piqiang Tan, Zhiyuan Hu, Hongjuan Ren
Under real road driving situation, automotive diesel engines are operating in transient mode, deviating from the desired optimal working condition as in the steady operation. Research for emission characteristics of the diesel engine and its control methods under transient operating conditions is gaining more concerns, because more stringent emission legislation continues to come into force, and transient process is responsible for a majority of diesel engine’s emission deterioration. In order to investigate diesel engines’ transient emission characteristics and develop effective methods to improve transient process for better organized combustion and engine performance, a lot of studies on engine transient process test, simulation and controlling are reported in nowadays literature. And slow acceleration has been proved to have the potential to reduce emissions of diesel engine. In parallel hybrid electric vehicles, engine and electric motor could work together when loading up.
2015-04-14
Journal Article
2015-01-0744
Terrence Alger, Raphael Gukelberger, Jess Gingrich, Barrett Mangold
The use of cooled EGR as a knock suppression tool is gaining more acceptance worldwide. As cooled EGR become more prevelant, some challenges are presented for engine designers. In this study, the impact of cooled EGR on peak cylinder pressure was evaluated. A 1.6 L, 4-cylinder engine was operated with and without cooled EGR at several operating conditions. The impact of adding cooled EGR to the engine on peak cylinder pressure was then evaluated with an attempt to separate the effect due to advanced combustion phasing from the effect of increased manifold pressure. The results show that cooled EGR's impact on peak cylinder pressure is solely due to the knock suppression effect, with the result that an EGR rate of 25% leads to an almost 50% increase in peak cylinder pressure at a mid-load condition. When combustion phasing was held constant, increasing the EGR rate had no effect on PCP.
2015-04-14
Technical Paper
2015-01-0742
Apostolos Karvountzis-Kontakiotis, Leonidas Ntziachristos, Zissis Samaras, Athanasios Dimaratos, Mark Peckham
Cyclic combustion variability is an undesirable characteristic of spark ignition engines that negatively affects engine performance and has a significant impact on fuel efficiency and pollutant emissions. The origins of cyclic combustion variability include variations in gas mixture motion and the turbulence at the beginning and during combustion, differences in the composition and homogeneity of the mixture and variations in spark plug discharge. The experimental investigation of combustion variability is usually focused on parameters that influence the evolution of combustion from cycle to cycle. However, combustion variability has also a significant effect on emissions, the study of which can be realized using fast response analyzers. In this work, the impact of cycle to cycle variability on performance and emissions is experimentally investigated. To this aim, a four-cylinder, high-speed port fuel injected, spark ignition engine was implemented.
2015-04-14
Technical Paper
2015-01-0772
Ashish J. Chaudhari, Vinayak Kulkarni, Niranjan Sahoo
Most undesirable emissions are exhausted by the spark ignition (SI) engines affect the environment and cause various problems such as ozone depletion, acid precipitation, global warming, respiratory hazards etc. The primary pollutants from the engine (such as NOx) which when mixed in the atmosphere react with ozone and create the secondary pollutant that are more harmful to human health. So, it is important to use alternative fuels having good performance and lower emissions as compared to petrol fuel. But, when the alternative fuels are considered, the important properties like octane number may or may not be same as that of conventional petroleum fuels (Morganti et. al., 2013). In such situation, the optimum compression ratio which gives best performance needs to be evaluated by variable compression ratio (VCR) study.
2015-04-14
Journal Article
2015-01-0902
Koichi Ashida, Hirofumi Maeda, Takashi Araki, Maki Hoshino, Koji Hiraya, Takao Izumi, Masayuki Yasuoka
To improve the fuel economy via high EGR, combustion stability is enhanced through the addition of H2, with its high flame-speed in air-fuel mixture. So, in order to realize on-board H2 production we developed fuel reformer which produces H2 rich gas from fuel by using heat and water vapor in the exhaust gas. One of the main issues to realize the fuel reformer was the catalyst deterioration under the actual exhaust gas condition. Catalyst reforming and exposure test were carried out to clear the influence of actual exhaust gas on the catalyst performance. “Fresh catalyst” showed good performance in generating hydrogen with concentration over 6% at 873K, but an Aged catalyst generated only half the concentration of hydrogen compared with Fresh catalyst. So we considered 2 measures to improve catalyst performance as follows: increased the rare earth components as a co-catalyst and silica as a binder, to improve water activation and inhibit sulfur absorption.
2015-04-14
Journal Article
2015-01-0892
Alastair Smith, Rod Williams
The formation of deposits within injector nozzle holes of common-rail injection fuel systems fitted to modern diesel cars can reduce and disrupt the flow of fuel into the combustion chamber. This can lead to a reduction in power output because of reduced or less efficient combustion; hence there is a great deal of interest in studying these deposits with the ultimate aim of controlling them. Through previous experimentation [1], a chassis dynamometer test method was developed which combined high fouling operating conditions with zinc doped fuels to give measureable and repeatable fouling rates within a 36 hour test, whilst remaining representative of real world driving by incorporating >50% of the test drive cycle at typical motorway road loads.
2015-04-14
Journal Article
2015-01-0890
Barbara Graziano, Florian Kremer, Stefan Pischinger, Karl Alexander Heufer, Hans Rohs
Nowadays restrictions on pollutant emissions produced by Internal Combustion Engines (ICEs) require a holistic investigation on alternative fuels able to optimize the combustion process and ensure a cleaner combustion. The Tailor-made Fuel from Biomass (TMFB) Cluster at RWTH Aachen University aims at designing optimal production processes for biofuels as well as ideal surrogate fuels for ICE applications. The TMFB Cluster’s scientific approach considers the fuel’s molecular structure as further degree of freedom for the optimization of both the biofuels’ production pathways and their combustion process. Thus, model-based specification of target parameters is of primary importance to improve the engine combustion performances and give feedback information to the production area. In particular a 3D CFD tool is used herein to underline the role played by the thermo-physical properties on the soot emissions in ICEs.
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