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Viewing 91 to 120 of 22466
2014-10-13
Technical Paper
2014-01-2566
Beini Zhou, Akira Kikusato, Kusaka Jin, Yasuhiro Daisho, Kiyotaka Sato, Hidefumi Fujimoto
Abstract This study simulates soot formation processes in diesel combustion using a large eddy simulation (LES) model, based on a one-equation subgrid turbulent kinetic energy model. This approach was implemented in the KIVA4 code, and used to model diesel spray combustion within a constant volume chamber. The combustion model uses a direct integration approach with a fast explicit ordinary differential equation (ODE) solver, and is additionally parallelized using OpenMP. The soot mass production within each computation cell was determined using a phenomenological soot formation model developed by Waseda University. This model was combined with the LES code mentioned above, and included the following important steps: particle inception during which acenaphthylene (A2R5) grows irreversibly to form soot; surface growth with driven by reactions with C2H2; surface oxidation by OH radical and O2 attack; and particle coagulation. The results obtained using our new model are compared to those generated using a RANS (RNG k-epsilon) model, and also to experimental data from the engine combustion network (ECN) of Sandia National Laboratories.
2014-10-13
Technical Paper
2014-01-2605
Cyrille Frottier, Marc Sens, Michael Rieß, Malte Wigger, Andreas Benz, Noriyuki Maekawa, Koji Onishi, Kazuhiro Oryoji, Kenichi Machida
Abstract In the near future, emissions legislation will become more and more restrictive for direct injection SI engines by adopting a stringent limitation of particulate number emissions in late 2017. In order to cope with the combustion system related challenges coming along with the introduction of this new standard, Hitachi Automotive Systems Ltd., Hitachi Europe GmbH and IAV GmbH work collaboratively on demonstrating technology that allows to satisfy EU6c emissions limitations by application of Hitachi components dedicated to high pressure injection (1). This paper sets out to describe both the capabilities of a new high pressure fuel system improving droplet atomization and consequently mixture homogeneity as well as the process of utilizing the technology during the development of a demonstrator vehicle called DemoCar. The Hitachi system consists of a fuel pump and injectors operating under a fuel pressure of 30 MPa. Revised spray patterns have been developed following an IAV process using optical spray vessel investigations as well as CFD simulation for a specific engine (boosted engine with 1.4L engine displacement and direct injection).
2014-10-13
Technical Paper
2014-01-2633
Sushant S. Pandurangi, Nicolò Frapolli, Michele Bolla, Konstantinos Boulouchos, Yuri M. Wright
Abstract Numerical simulations of a heavy-duty diesel engine fuelled with n-heptane have been performed with the conditional moment closure (CMC) combustion model and an embedded two-equation soot model. The influence of exhaust gas recirculation on the interaction between post- and main- injection has been investigated. Four different levels of EGR corresponding to intake ambient oxygen volume fractions of 12.6, 15, 18 and 21% have been considered for a constant intake pressure and temperature and unchanged injection configuration. Simulation results have been compared to the experimental data by means of pressure and apparent heat-release rate (AHRR) traces and in-cylinder high-speed imaging of natural soot luminosity and planar laser-induced incandescence (PLII). The simulation was found to reproduce the effect of EGR on AHRR evolutions very well, for both single- and post-injection cases. Further a direct comparison of the computed and measured temporal evolution of soot luminosity is presented for the 18% initial oxygen volume fraction case.
2014-10-13
Technical Paper
2014-01-2628
Loic Francqueville, Jean-Baptiste Michel
Abstract EGR dilution is a promising way to improve fuel economy of Spark-Ignited (SI) gasoline engines. In particular, at high load, it is very efficient in mitigating knock at low speed and to decrease exhaust temperature at high speed so that fuel enrichment can be avoided. The objective of this paper is to better understand the governing mechanisms implied in EGR-diluted SI combustion at high load. For this purpose, measurements were performed on a modern, single-cylinder GDI engine (high tumble value, multi-hole injector, central position). In addition 0-D and 1-D Chemkin simulations (reactors and flames) were used to complete the engine tests so as to gain a better understanding of the physical mechanisms. EGR benefits were confirmed and characterized at 19 bar IMEP: net ISFC could be reduced by 17% at 1200rpm and by 6% at 5000rpm. At low speed, knock mitigation was the main effect, improving the cycle efficiency by a better combustion phasing. At high speed, stoichiometric operation could be achieved, avoiding fuel-costly enrichment.
2014-10-13
Technical Paper
2014-01-2632
Clemens Brückner, Panagiotis Kyrtatos, Konstantinos Boulouchos
Abstract New emission legislations applicable in the near future to sea-going vessels, off-road and off-highway vehicles require drastic nitric oxides emission reduction. A promising approach to achieve part of this decrease is charge air temperature reduction using Miller timing. However, it has been shown in literature that the reduction potential is limited, achieving a minimum in NOx emissions at a certain end-of-compression temperature. Further temperature reduction has shown to increase NOx emissions again. Some studies have shown that this increase is correlated to an increased amount of premixed combustion. In this work, the effects of pilot injection on engine out NOx emissions for very early intake valve closure (i.e. extreme Miller), high boost pressures and cold end-of-compression in-cylinder conditions are investigated. The experiments are carried out on a 3.96L single cylinder heavy-duty common-rail Diesel engine operating at 1000 rpm and at constant global air-to-fuel ratio.
2014-10-13
Technical Paper
2014-01-2676
Takayuki Fuyuto, Masahiro Taki, Reiko Ueda, Yoshiaki Hattori, Hiroshi Kuzuyama, Tsutomu Umehara
Abstract An author's previous studies addressed a combustion system which reduces emissions, noise, and fuel consumption by using PCCI with the split injection of fuel. This concept relies on the premixed combustion of the first injected fuel and accelerated oxidation by the second injected fuel. Although this combustion system requires the optimization of the timing of the second injection, the details of how noise and emissions are reduced have not been elucidated. In this paper, the authors explain the mechanism whereby emissions and noise are reduced by the second injection. In-cylinder visualizations and numerical simulations both showed an increase in smoke and CO as the second injection timing was advanced, as induced by the inhibited oxidation of the rich flame. When the second injection timing is excessively retarded, the amount of soot forming around the near-nozzle increased. The second fuel injection at the optimum timing can mix with the air in the inner-region of the cavity, such that no soot is formed in the near-nozzle region.
2014-10-13
Technical Paper
2014-01-2806
Isaline Lefort, Jose Herreros, Athanasios Tsolakis
Abstract This study investigates the potential of using a partial flow filter (PFF) to assist a wall flow diesel particulate filter (DPF) and reduce the need for active regeneration phases that increase engine fuel consumption. First, the filtration efficiency of the PFF was studied at several engine operating conditions, varying the filter space velocity (SV), through modification of the exhaust gas flow rate, and engine-out particulate matter (PM) concentration. The effects of these parameters were studied for the filtration of different particle size ranges (10-30 nm, 30-200 nm and 200-400 nm). For the various engine operating conditions, the PFF showed filtration efficiency over 25% in terms of PM number and mass. The PFF filtration behaviour was also investigated at idle engine operation producing a high concentration of nuclei particulates for which the filter was able to maintain 60% filtration efficiency. After a 14 hour soot loading phase, the filter trapping efficiency remained over 20% and showed unexpectedly high small PM filtration efficiency.
2014-10-13
Technical Paper
2014-01-2817
Kenan Muric, Ola Stenlaas, Per Tunestal, Bengt Johansson
In the last couple of decades, countries have enacted new laws concerning environmental pollution caused by heavy-duty commercial and passenger vehicles. This is done mainly in an effort to reduce smog and health impacts caused by the different pollutions. One of the legislated pollutions, among a wide range of regulated pollutions, is nitrogen oxides (commonly abbreviated as NOx). The SCR (Selective Catalytic Reduction) was introduced in the automotive industry to reduce NOx emissions leaving the vehicle. The basic idea is to inject a urea solution (AdBlue™) in the exhaust gas before the gas enters the catalyst. The optimal working temperature for the catalyst is somewhere in the range of 300 to 400 °C. For the reactions to occur without a catalyst, the gas temperature has to be at least 800 °C. These temperatures only occur in the engine cylinder itself, during and after the combustion. In this paper a study is presented where a second injector is installed in a Scania D13 cylinder head for urea injection purposes.
2014-10-13
Technical Paper
2014-01-2822
Achinta Varna, Konstantinos Boulouchos, Alexander Spiteri, Panayotis Dimopoulos Eggenschwiler, Yuri M. Wright
Simulations for a pressure-assisted multi-stream injector designed for urea-dosing in a selective catalytic reduction (SCR) exhaust gas system have been carried out and compared to measurements taken in an optically accessible high-fidelity flow test rig. The experimental data comprises four different combinations of mass flow rate and temperature for the gas stream with unchanged injection parameters for the spray. First, a parametric study is carried out to determine the importance of various spray sub-models, including atomization, spray-wall interaction, buoyancy as well as droplet coalescence. Optimal parameters are determined using experimental data for one reference operating condition. The model is subsequently applied to all operating conditions with unaltered parameters and validated by means of the measured droplet velocity fields, droplet diameter distributions and spray-tip propagations which have been characterized by means of Particle Image Velocimetry (PIV), Phase Doppler Anemometry (PDA) and shadow imaging.
2014-10-13
Technical Paper
2014-01-2728
Romaeo Dallanegra, Rinaldo Caprotti
Abstract Internal Diesel Injector Deposits (IDIDs) have been known for some time. With the latest powertrains becoming ever more sophisticated and reliant on efficient fuel delivery, the necessity for a continued focus on limiting their formation remains. Initial studies probed both carbonaceous based/ashless polymeric and sodium salt based IDIDs. The reported occurrence of the latter variety of IDID has declined in recent years as a result of the removal of certain additives from the diesel distribution system. Conversely, ashless polymeric based deposits remain problematic and a regular occurrence in the field. The body of work presented in this contribution is an extension to that reported in SAE paper 2014-01-1401 which showed how a particular Fuel Borne Catalyst (FBC) additive has the ability to significantly reduce the formation of ashless polymeric deposits formed from the reaction of Poly-isobutylene Succinic Imides (PIBSI) with fatty acid and the ability for the same additive to also be neutral towards the formation of sodium salt based deposits.
2014-10-13
Technical Paper
2014-01-2697
Kiyoshi Kawasaki, Soichiro Kubo, Koji Yamane, Chihiro Kondo
Abstract The main aim of this study is to investigate the effect of NO and NO2 on the combustion characteristics such as pressure development and combustion phasing in natural gas HCCI engine. A secondary aim is to demonstrate a method of obtaining a significant sensitizing effect on methane oxidation reaction from small amounts of NOx. Experiments were conducted using a rapid compression-expansion machine that was constructed from a single-cylinder diesel engine. First, the sensitizing effect of NO and NO2 on the HCCI combustion of natural gas was investigated in a case where NOx was uniformly mixed into a charge. Obtained results show that the auto-ignition timing is significantly advanced and an acute heat release is promoted by adding either NO or NO2. Second, the effect of non-uniform mixing of NOx into an air-fuel mixture was investigated according to our expectation that the existence of local spots with high NOx concentrations can assist auto-ignition more effectively than the same amount of NOx homogeneously distributed.
2014-10-13
Technical Paper
2014-01-2720
Jim Barker, Jacqueline Reid, Colin Snape, David Scurr, William Meredith
Abstract Since 2009, there has been a rise in deposits of various types found in diesel fuel injection systems. They have been identified in the filter, the injector tip and recently inside the injector. The latter internal diesel injector deposits (IDIDs) have been the subject of a number of recent publications, and are the subject of investigations by CRC (Central Research Council Diesel Performance Group-Deposit Panel Bench/ Rig Investigation sub panel) in the US and CEN (Committee European de Normalisation TC19/WG24 Injector Deposit Task Force) and CEC (Coordinating European Council TDFG-110 engine test) in Europe. In the literature one of the internal injector deposit types, amide lacquers, has been associated with a poorly characterised noncommercial low molecular weight polyisobutylene succinimide detergent which also lacked provenance. This work will describe a well characterised non-commercial low molecular weight polyisobutylenesuccinimide, the engine tests associated with it and the spectroscopic analysis of the needle of the resultant stuck injectors.
2014-10-13
Technical Paper
2014-01-2713
Jianyi Tian, Hongming Xu, Ramadhas Arumugam Sakunthalai, Dai Liu, Cheng Tan, Akbar Ghafourian
Abstract Engine transient operation has attracted a lot of attention from researchers due to its high frequency of occurrence during daily vehicle operation. More emissions are expected compared to steady state operating conditions as a result of the turbo-lag problem. Ambient temperature has significant influences on engine transients especially at engine start. The effects of ambient temperature on engine-out emissions under the New European Driving Cycle (NEDC) are investigated in this study. The transient engine scenarios were carried out on a modern 3.0 L, V6 turbocharged common rail diesel engine fuelled with winter diesel in a cold cell within the different ambient temperature ranging between +20 °C and −7 °C. The engine with fuel, coolant, combustion air and lubricating oil were soaked and maintained at the desired test temperatures during the transient scenarios. Instantaneous engine performances including torque and speed, gaseous emissions such as CO, THC and NOx, and particulate emissions for its number and mass are analyzed during each transient scenario under different ambient conditions.
2014-10-13
Technical Paper
2014-01-2719
Alex Harrison, Roger Cracknell, Jens Krueger-Venus, Lev Sarkisov
Abstract Carbonaceous deposits can accumulate on various surfaces of the internal combustion engine and affect its performance. The porous nature of these deposits means that they act like a “sponge”, adsorbing fuel components and changing both the composition and the amount of fuel in the combustion chamber. Here we use a previously developed and validated model of engine deposits to predict adsorption of normal heptane, isooctane, toluene and their mixtures in deposits of different origin within a port fuel injected spark ignition engine (Combustion Chamber Deposits, or CCDs, and Intake Valve Deposits, or IVDs) and under different conditions. We explore the influence of molecular structure of adsorbing species, composition of the bulk mixture and temperature on the uptake and selectivity behaviour of the deposits. While deposits generally show high capacity toward all three components, we observe that selectivity behaviour is a more subtle and complex property.
2014-10-13
Technical Paper
2014-01-2637
Katsufumi Kondo, Junya Takahashi, Tetsuya Aizawa
Abstract Wall-deposition of soot particles occurs due to the interaction between spray flame and cylinder liner wall/piston surface, which can potentially affect soot morphology after the in-flame formation/oxidation processes and before the exit from engine cylinder. In order to investigate these effects, flame wall impingement was simulated in a constant volume combustion vessel and thermophoretic soot sampling was conducted for Transmission Electron Microscopic analysis. A TEM grid for the sampling was exposed to a single-shot diesel spray flame multiple times and the variation of soot morphology (concentration, primary particle diameter and aggregate gyration radius) among the multiple exposures was compared. Furthermore, a newly designed impingement-type sampler vertically exposed the grid to the spray flame and sampled soot particles under different boundary condition from that of conventionally used skim-type sampler. The morphology of soot particles sampled by the impingement- and skim-type samplers were compared.
2014-10-13
Technical Paper
2014-01-2642
Masaki Kuribayashi, Yuta Mizutani, Yutaro Ishizuka, Natsuki Taki, Tetsuya Aizawa
Abstract For better understanding of soot formation and oxidation processes in diesel combustion, effects of ambient oxygen concentration on in-flame diesel soot particle properties including concentration, size, number density and morphology were investigated in a constant volume combustion vessel via simultaneous LII (Laser-Induced Incandescence) / LS (Laser Scattering) imaging techniques and TEM (Transmission Electron Microscopy) analysis. An analysis of LII and LS images yielded 2-dimensional distribution images of concentration, size and number density of soot particles in diesel spray flame, based on a practical assumption that LII and LS signals are proportional to the soot particle size to the power of 3 and 6, respectively. The laser measurements and TEM analysis results of soot particles directly sampled in the diesel spray flame showed a consistent general trend that in the case of 21% ambient O2 concentration soot is formed earlier in the upstream region and disappears earlier due to faster oxidation, while in the case of 15% ambient O2 concentration, soot is formed later in more downstream region and disappears more slowly.
2014-10-13
Technical Paper
2014-01-2658
Denis W. Gill, Herwig Ofner, Carsten Stoewe, Karl Wieser, Ernst Winklhofer, Masaaki Kato, Takamasa Yokota, Jost Weber
Abstract For nearly twenty years, DiMethyl Ether has been known to be an outstanding fuel for combustion in diesel cycle engines. Not only does it have a high Cetane number, it burns absolutely soot free and produces lower NOx exhaust emissions than the equivalent diesel. However, the physical properties of DME such as its low viscosity, lubricity and bulk modulus have negative effects for the fuel injection system, which have both limited the achievable injection pressures to about 500 bar and DME's introduction into the market. To overcome some of these effects, a common rail fuel injection system was adapted to operate with DME and produce injection pressures of up to 1000 bar. To understand the effect of the high injection pressure, tests were carried out using 2D optically accessed nozzles. This allowed the impact of the high vapour pressure of DME on the onset of cavitation in the nozzle hole to be assessed and improve the flow characteristics. CFD simulation was also used to assist in the interpretation of the 2D test results.
2014-10-13
Technical Paper
2014-01-2773
Vasu Kumar, Naveen Kumar, Vishvendra Tomar, Gagneet Kalsi
Abstract The world today is facing the effect of the dependence on fossil fuels. Also, the rate of consumption of Fossil derived fuels is alarming. The use of non-conventional energy sources is to be increased so as to tackle the global climatic changes, environmental pollution and also to lower down the rate of depletion of fossil fuels. The urgent need to replace the petroleum products having harmful emissions has leaded us to the Biodiesel. Biodiesel is a well-known alternative for diesel with an advantage over the later because of its biodegradable, less toxic nature, superior lubricity, better emission characteristics and in a way environment friendly. The present study focuses on the comparative study and analysis of performance and emission characteristics of a light duty diesel engine on blends of Fish oil Biodiesel in Diesel and Calophyllum Inophyllum Oil Biodiesel in Diesel. The blends taken for the study are 5% (V/V), 10% (V/V), 15% (V/V) of fish oil methyl ester in diesel as FOMED05, FOMED10, FOMED15 and 5% (v/v), 10% (v/v), 15% (v/v) of calophyllum inophyllum oil methyl ester in diesel as COMED05, COMED10, COMED15 respectively.
2014-10-13
Technical Paper
2014-01-2826
Jon Andersson, John May, Cecile Favre, Dirk Bosteels, Simon de Vries, Matthew Heaney, Matthew Keenan, Jonathon Mansell
Abstract The exhaust emissions of two Euro 6 diesel cars with different emissions control systems have been evaluated both on the road and over various chassis dynamometer test cycles. European emissions limits are currently set using the New European Driving Cycle (NEDC), but the European Commission is preparing additional test procedures to ensure that emissions are well controlled both in real-world use and over the legislative test cycle. The main focus of this work on ‘Real Driving Emissions’ (RDE) is on measurements using Portable Emissions Measurement Systems (PEMS) in truly representative, on-road, driving. A key focus of the test programme, undertaken as a collaboration between AECC (the Association for Emissions Control by Catalyst) and Ricardo UK, was therefore the use of PEMS systems to measure on-road emissions of both gaseous pollutants and particulate matter. This included measurement of particle number emissions with a new candidate system for this type of measurement. The results from this testing are compared with emissions measured over four different chassis dynamometer test cycles - the current legislative cycle (New European Driving Cycle, NEDC); the Common Artemis suite of test cycles (CADC) that is widely used in emissions modelling; the new Worldwide Light-duty Test Cycle (WLTC) defined by the UN Working Party on Pollution and Energy (GRPE) as part of the development of the Worldwide harmonised Light vehicles Test Procedure (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.
2014-10-13
Technical Paper
2014-01-2815
Anders Widd, Magnus Lewander
Abstract The Selective Catalytic Reduction (SCR) catalyst with ammonia as reducing agent plays a central role in today's exhaust after-treatment systems for heavy-duty vehicles and there is a wide selection of possible catalytic materials to use. In order to facilitate the design of future catalysts, several aspects of the materials must be evaluated both in steady-state and transient operation. To this end, this paper presents a methodology for comparing the dynamic properties of different catalysts using full-size engine testing. The studied characteristics include the ammonia storage capacity, the effect of starting with an empty catalyst, the transient response to temperature gradients and changes in the urea dosing level. The temperature response is of particular importance in transient operation, where temperature increases may lead to substantial ammonia slip. A vanadium catalyst is compared to a Cu-SAPO-34 catalyst, and they show significant differences in their dynamic response.
2014-10-13
Technical Paper
2014-01-2834
Barouch Giechaskiel, Urbano Manfredi, Giorgio Martini
Abstract In the current diesel vehicle exhaust emissions legislation Particle Number (PN) limits for solid particles >23 nm are prescribed. The legislation was extended to include Gasoline Direct Injection (G-DI) vehicles since September 2014. Target of this paper was to investigate whether smaller than 23 nm solid particles are emitted from engines in considerable concentration focusing on G-DI engines. The literature survey and the experimental investigation of >15 vehicles showed that engines emit solid sub-23 nm particles. The average percentage over a test cycle for G-DIs (30-40%) is similar to diesel engines. These percentages are relatively low considering the emission limit levels (6×1011 p/km) and the repeatability (10-20%) of the particle number method. These percentages are slightly higher compared to the percentages expected theoretically not to be counted due to the 23 nm cut-off size (5-15%). Higher fraction can be measured with high ethanol content fuels, at sub-zero ambient temperatures and when additives are added in the fuel or lubricant.
2014-10-13
Technical Paper
2014-01-2832
Barouch Giechaskiel, Giorgio Martini
Abstract In the current heavy-duty engine and light-duty diesel vehicle exhaust emission legislation Particle Number (PN) limits for solid particles >23 nm are prescribed. The legislation was extended to include Gasoline Direct Injection (G-DI) vehicles since September 2014 and will be applied to Non-Road Mobile Machinery engines in the future. However there are concerns transferring the same methodology to other engine technologies, where higher concentration of sub-23 nm particles might exist. This paper focuses on the capabilities of existing PN measurement equipment on measuring solid particles smaller than 23 nm. More specifically, it is investigated: 1) whether it is feasible to easily modify existing systems to measure lower particle sizes, 2) whether all volatile particles can be removed efficiently in the PN measurement systems, 3) whether any artifacts happen in the PN systems (e.g. formation of non-volatile particles due to pyrolysis), and 4) whether by lowering the lower size the measurement uncertainty increases significantly.
2014-10-13
Technical Paper
2014-01-2846
Om Parkash Bhardwaj, Bernhard Lüers, Bastian Holderbaum, Thomas Koerfer, Stefan Pischinger, Markku Honkanen
Abstract The present work is a continuation of the earlier published results by authors on the investigation of Hydrogenated Vegetable Oil (HVO) on a High Efficiency Diesel Combustion System (SAE Int. J. Fuels Lubr. Paper No. 2013-01-1677 and JSAE Paper No. 283-20145128). In order to further validate and interpret the previously published results of soot microstructure and its consequences on oxidation behavior, the test program was extended to analyze the impact of soot composition, optical properties, and physical properties such as size, concentration etc. on the oxidation behavior. The experiments were performed with pure HVO as well as with petroleum based diesel and today's biofuel (i.e. FAME) as baseline fuels. The soot samples for the different analyses were collected under constant engine operating conditions at indicated raw NOx emissions of Euro 6 level using closed loop combustion control methodology. The oxidation behavior results of optimized Thermogravimetric Analysis (TGA) correspond well with the previously published (part-1) results of the kinetics of soot oxidation (i.e. activation energy, reaction rate constant and regen. temperature) conducted on a Laboratory Gas Test Bench using a Temperature Programmed Oxidation (TPO).The results suggest that the soot oxidation temperatures of the HVO decreased by ∼43 °C and 37 °C with O2 and NO2 respectively, as compared to petroleum based diesel.
2014-10-13
Technical Paper
2014-01-2844
Matthias Stark, Richard Mittler
Abstract Understanding tribodynamic effects is crucial when aiming to reduce lube oil consumption and related exhaust gas emissions. This report briefly describes the lubrication concept of large two stroke marine diesel engines and different contributors to the lube oil balance of such an engine. Addressing possible measures to influence the contribution of lubrication system parameters on exhaust gas emissions requires a detailed analysis of possible actions to achieve the expected improvement. Activities to enhance lubrication system performance concentrate on: Modifications of relevant engine components The application of experimentally gained data to support computational simulation models The application of suitable validation approaches This report in particular highlights piston ring pack optimizations on basis of computational simulation. One major step in developing a new piston ring pack dynamic simulation tool was achieved by implementing two stroke engine specific measurement results of general engine performance data, as well as complex information of tribo- and gas-dynamic effects on piston ring motion and lube oil film.
2014-10-13
Technical Paper
2014-01-2848
Matthew McAllister, Stephen Smith, Paul Kapus, Khai Vidmar, Alexander Hochnetz
This paper describes the findings of a design, simulation and test study into how to reduce particulate number (Pn) emissions in order to meet EU6c legislative limits. The objective of the study was to evaluate the Pn potential of a modern 6-cylinder engine with respect to hardware and calibration when fitted to a full size SUV. Having understood this capability, to redesign the combustion system and optimise the calibration in order to meet an engineering target value of 3×1011 Pn #/km using the NEDC drive cycle. The design and simulation tasks were conducted by JLR with support from AVL. The calibration and all of the vehicle testing was conducted by AVL, in Graz. Extensive design and CFD work was conducted to refine the inlet port, piston crown and injector spray pattern in order to reduce surface wetting and improve air to fuel mixing homogeneity. The design and CFD steps are detailed along with the results compared to target. The redesigned high tumble combustion system enabled the engine to meet challenging combustion stability targets at low Pn-levels.
2014-10-13
Technical Paper
2014-01-2768
George Karavalakis, Daniel Short, Vincent Chen, Carlos Espinoza, Tyler Berte, Thomas Durbin, Akua Asa-Awuku, Heejung Jung, Leonidas Ntziachristos, Stavros Amanatidis, Alexander Bergmann
Abstract The relationship between ethanol and iso-butanol fuel concentrations and vehicle particulate matter emissions was investigated. This study utilized a gasoline direct injection (GDI) flexible fuel vehicle (FFV) with wall-guided fueling system tested with four fuels, including E10, E51, E83, and an iso-butanol blend at a proportion of 55% by volume. Emission measurements were conducted over the Federal Test Procedure (FTP) driving cycle on a chassis dynamometer with an emphasis on the physical and chemical characterization of particulate matter (PM) emissions. The results indicated that the addition of higher ethanol blends and the iso-butanol blend resulted in large reductions in PM mass, soot, and total and solid particle number emissions. PM emissions for the baseline E10 fuel were characterized by a higher fraction of elemental carbon (EC), whereas the PM emissions for the higher ethanol blends were more organic carbon (OC) in nature. The higher ethanol blends and the iso-butanol blend showed lower concentrations of accumulation mode particles and size distributions shifted to smaller particle sizes compared to E10.
2014-10-13
Technical Paper
2014-01-2811
Michal Vojtisek-Lom, Martin Pechout, Michael Fenkl
Abstract The paper focuses on portable “on-board” instrumentation and methods for evaluation of exhaust emissions from scooters and various small machinery under real-world driving conditions. Two approaches are investigated here. In one, a miniature on-board system mounted on the equipment itself performs online measurements of the concentrations of the pollutants of interest (HC, CO, CO2, NOx, some property of particulate matter), and measurement or computation of the intake air flow. This approach has been used on a 50 cm3 scooter fitted with a 14-kg on-board system and driven on local routes. Measured concentrations of gaseous compounds, particle mass and total particle length were multiplied with the corresponding intake air flow computed from measured engine rpm, intake air manifold pressure and temperature. In the second approach, a full-flow dilution tunnel, gas analyzers and particle measurement or sampling devices are mounted on an accompanying hand cart or vehicle. This approach has been used with weedeaters, chainsaws, and lawnmowers.
2014-10-13
Technical Paper
2014-01-2812
Ahmad Khalfan, Hu Li, Gordon Andrews
Abstract The tailpipe exhaust emissions were measured using a EURO4 emissions compliant SI car equipped with on-board measurement systems such as a FTIR system for gaseous emission, a differential GPS for velocity, altitude and position, thermal couples for temperatures, and a MAX fuel meter for transient fuel consumption. Various nitrogen species emissions (NO, NO2, NOx, NH3, HCN and N2O) were measured at 0.5 Hz. The tests were designed and employed using two real world driving cycles/routes representing a typical urban road network located in a densely populated area and main crowded road. Journeys at various times of the day were conducted to investigate traffic conditions impacts such as traffic and pedestrian lights, road congestion, grade and turning on emissions, engine thermal efficiency and fuel consumption. The time aligned vehicle moving parameters with Nitrogen pollutant emission data and fuel consumption enabled the micro-analysis of correlations between these parameters. The average data for journeys such as emissions, thermal efficiency and fuel consumption were presented, though this paper is focused on nitrogen compounds.
2014-10-13
Technical Paper
2014-01-2570
Karthik Puduppakkam, Chitralkumar Naik, Ellen Meeks, Christian Krenn, Roswitha Kroiss, Johannes Gelbmann, Guenther Pessl
Abstract An important goal for CFD simulation in engine design is to be able to predict the combustion behavior as operating conditions are varied and as hardware is modified. Such predictive capability allows virtual prototyping and optimization of design parameters. For low-temperature combustion conditions, such as with high rates of exhaust-gas recirculation, reliable and accurate predictions have been elusive. Soot has been particularly difficult to predict, due to the dependence of soot formation on the fuel composition and the kinetics detail of the fuel combustion. Soot evolution in diesel engines is impacted by fuel and chemistry effects, as well as by spray dynamics and turbulence. In this work, we present a systematic approach to accurately simulate combustion and emissions in a high-performance BMW diesel engine. This approach has been tested and validated against experimental data for a wide range of operating conditions. Nine operating conditions have been modeled that span engine loads of 3-21 bar MEP, engine speeds of 1000-4400 rpm and external EGR of 0-38%.
2014-10-13
Technical Paper
2014-01-2795
Wim van Dam, James Booth, Jimmy Pitta, Gary Parsons
Advancement in Heavy Duty Diesel Engine Oils has, for approximately two decades, been driven by the ever more stringent emission legislation for NOx and Particulates. Over the last few years, the focus has shifted to reducing CO2 emissions and reducing operating cost by improving the engine's fuel economy. With fuel economy as an important new technology driver, the industry is exploring and introducing diesel engine oils of viscosity grades that used to be applied solely in passenger car engines, such as SAE 10W-30 and even SAE 5W-30. To avoid misapplication, API has decided that heavy duty diesel engine oils, most of which are formulated close to the maximum 0.12% phosphorus limit in the API C specification, can no longer add the API S gasoline engine claim. The only way to create a lubricant that carries both an API C and S claim for mixed fleet or municipality application, is to formulate at less than 0.08% phosphorus, a limit that was adopted in API S specifications because there are indications that phosphorus may foul three-way catalysts used with gasoline engines to control tailpipe emissions.
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