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Viewing 1 to 30 of 14431
2010-10-25
Journal Article
2010-01-2223
Alessandro di Gaeta, Umberto Montanaro, Silvio Massimino, Carlos Ildefonso Hoyos Velasco
Nowadays, developing of effective camless engine systems, allowing Variable Valve Actuation (VVA), is one of the fundamental automotive challenge to increase engine power, reduce fuel consumption and pollutant emissions, as well as improve the engine efficiency significantly. Electromechanical devices based on double electromagnets have shown to be a promising solution to actuate engine valves during normal engine cycle due to their efficient working principle. Conversely, this solution requires special care at the key-on engine for the first valve lift, when the valve must be shifted from the middle equilibrium position to the closing one with limited coil currents and power requirements as well. Despite the central role of the first catching problem, few attempts have been done into the existing literature to tackle it systematically.
2010-10-25
Technical Paper
2010-01-2225
Alberto Boretti
Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies.
2010-09-28
Technical Paper
2010-32-0046
P. Shanmugam, T. Kathiresan, N. Senthilnathan, AS. Anbukarasu, R. Vinoth Balaram, K. Prabu, MG. Naveenkumar
Pollutants are harmful to human and other living beings on the earth. Thus emission reduction plays a very important role in the survival of living beings. Hydrocarbons (HC), Carbon monoxide (CO), Nitrogen oxides (NOx) are the emission constituents which results in smog, respiratory problems in human beings, acid rain respectively. Hence, Indian government has taken necessary steps to reduce these emissions and imposed various level of norms like BSI, BSII and BSIII on 2/3 wheeler industries in the year 2000, 2005 and 2010 respectively. Presently in India, BSII is in force and from October 2010 BSIII will be introduced. BSIII 3 wheeler norm, the CO emission level is reduced by 44.4% and HC+NOx is reduced by 37.5%. The main objective of this work is to reduce the emissions like HC, which is due to unburnt fuels, NOx, which is due to high engine pressures and temperatures and CO, which is a byproduct of incomplete combustion.
2010-09-28
Technical Paper
2010-32-0060
Rainer Aufischer
Environmental regulations all over the globe and the demand on fuel efficient engines have increased bearing loads dramatically over the last 20 years, especially in small and high speed Diesel engines. Lead containing Bronze bearings, often with a Lead based overlay have become a standard in the automotive industry and are used over decades. Due to the harmful and poisonous effect of lead on the environment the European Union has set up the Vehicle end-of-life Regulation to reduce use of lead, also in tribological products. In order to fulfill the high load capability and the necessary tribological behavior of engine bearings new approaches in fatigue, temperature stability and Tribology has to be taken. Basic investigation of the tribological working principles in bearings combining short term failure mechanism and long term behavior were carried out to understand the interaction of materials, layers and lubrication.
2010-09-28
Technical Paper
2010-32-0059
Silvio Barbarelli, Sergio Bova, Rocco Piccione
Variable-displacement lubricating pumps are an attractive solution for reducing fuel consumption and emissions in motorcycle engines. In this prospective, modeling and experimental analysis are very useful means for a deeper understanding of pump operation and for effectively implementing pump control. Zero-dimensional simulation results of a 7-vane pump were compared with the experimental data of dynamic piezo-resistive pressure transducers fitted into the casing of a pump prototype, which was operated under steady-state conditions at different rotational speeds and eccentricity values. The experimental data exhibit oscillations which were explained by taking into account the pressure transducers dynamics, as a result of the transducer location in the pump casing, of the air dissolved in the hydraulic fluid and of the geometry of the tubing/transducer system.
2010-10-05
Technical Paper
2010-01-2054
Cenk Dinc, Ozgur Arslan, Tolga Akgun, Roger Almenar
The purpose of this study is to present the effects of several design actions on engine cooling performance of a heavy duty construction truck, with the aid of numerical and experimental investigations. The design actions involve the modifications of the front end geometry and implementation of different heat exchangers and fans. The sensitivity of engine cooling performance related to the concerned design changes is monitored with the variation in the engine coolant temperature. Numerical investigations are carried out with the Reynolds averaged Navier Stokes Equations based CFD solver, UH3D, and the results are validated with the experiments conducted at Behr wind tunnel facilities in Stuttgart. It is seen that the experimental results show good correlation with the CFD simulations.
2010-10-25
Technical Paper
2010-01-2154
Alberto Boretti
Current flexi fuel gasoline and ethanol engines have brake efficiencies generally lower than a dedicated gasoline engines because of the constraints to accommodate a variable mixture of the two fuels. Considering ethanol has a few advantages with reference to gasoline, namely the higher octane number and the larger heat of vaporization, the paper explores the potentials of dedicated pure ethanol engines using the most advanced techniques available for gasoline engines, specifically direct injection, turbo charging and variable valve actuation. Computations are performed with state-of-the-art, well validated, engine and vehicle performance simulations packages, generally accepted to produce accurate results targeting major trends in engine developments. The higher compression ratio and the higher boost permitted by ethanol allows larger top brake efficiencies than gasoline, while variable valve actuation produces small penalties in efficiency changing the load.
2010-10-25
Technical Paper
2010-01-2155
Stefan de Goede, Tiaan Rabe, Riaan Bekker, Sibusiso Mtongana, John Edwards
Direct Injection Spark Ignition (DISI) engine technology is becoming increasingly common in the South African and global vehicle parcs. South Africa is in a unique position because a significant portion of all liquid fuels consumed are synthetically produced from coal and gas. These fuels are mainly supplied into the inland regions, particularly the Gauteng province, the economic heartland of South Africa and the most densely populated area in the country. It is important to understand the performance of synthetic fuels in the latest generation engines, in order to ensure that these fuels are fit for use in these new applications. The latest generation DISI gasoline engines (also known as Gasoline Direct Injection™ and Fuel Stratified Injection™) differ significantly in operation to older Port-Fuel-Injected (PFI) engines.
2010-10-25
Journal Article
2010-01-2152
Heechang Oh, Choongsik Bae, Kyoungdoug Min
An experimental study was performed to evaluate the effects of ethanol blending on to gasoline spray and combustion characteristics in a spray-guided direct-injection spark-ignition engine under lean stratified operation. The spray characteristics, including local homogeneity and phase distribution, were investigated by the planar laser-induced fluorescence and the planar Mie scattering method in a constant volume chamber. Therefore, the single cylinder engine was operated with pure gasoline, 85 %vol, 50 %vol and 25vol % ethanol blended with gasoline (E85, E50, E25) to investigate the combustion and exhaust emission characteristics. Ethanol was identified to have the potential of generating a more appropriate spray for internal combustion due to a higher vapor pressure at high temperature conditions. The planar laser-induced fluorescence image demonstrated that ethanol spray has a faster diffusion velocity and an enhanced local homogeneity.
2010-10-25
Technical Paper
2010-01-2153
Mayank Mittal, David L.S. Hung, Guoming Zhu, Harold Schock
An experimental study is performed to investigate the fuel impingement on cylinder walls and piston top inside a direct-injection spark-ignition engine with optical access to the cylinder. Three different fuels, namely, E85, E50 and gasoline are used in this work. E85 represents a blend of 85 percent ethanol and 15 percent gasoline by volume. Experiments are performed at different load conditions with the engine speeds of 1500 and 2000 rpm. Two types of fuel injectors are used; (i) High-pressure production injector with fuel pressures of 5 and 10 MPa, and (ii) Low-pressure production-intent injector with fuel pressure of 3 MPa. In addition, the effects of split injection are also presented and compared with the similar cases of single injection by maintaining the same amount of fuel for the stoichiometric condition. Novel image processing algorithms are developed to analyze the fuel impingement quantitatively on cylinder walls and piston top inside the engine cylinder.
2010-10-25
Technical Paper
2010-01-2149
Zhao Zhenfeng, Ying Huang, Fujun Zhang, Changlu Zhao, Kai Han
In this paper the experiments of hydraulic free piston diesel engine is described. The experimental data were obtained from measurement instruments on the free piston diesel engine that has been developed by Beijing Institute of Technology [ 1 ]. This article discusses the influences of compression pressure, injection timing, and combustion process to the free piston diesel engine principle. The compression process experiment shows that the piston velocity, the compression ratio can be controlled by adjusting the compression pressure. With the increasing of the compression pressure, there is a growing a compression ratio and piston velocity. The study on injection timing shows that the injection timing impacts the cylinder pressure peak value and the pressure peak arrival time. The combustion process is quite different from the crankshaft engine because of the unique piston movement characteristics of the hydraulic free piston engine.
2010-10-25
Technical Paper
2010-01-2146
Massimo Rundo
Scope of this work is the analysis of the energy consumed by lubricating gear pumps for automotive applications during a driving cycle. This paper presents the lumped parameter simulation model of gerotor lubricating pumps and the comparison between numerical outcomes and experimental results. The model evaluates the power required to drive the pump and the cumulative energy consumed in the driving cycle. The influence of temperature variations on leakage flows, viscous friction torque and lubricating circuit permeability is taken into account. The simulation model has been validated by means of a test rig for hydraulic pumps able to reproduce the typical speed, temperature and load profiles during a NEDC driving cycle. Experimental tests, performed on a crankshaft mounted pump for diesel engines, have confirmed a good matching with the simulation model predictions in terms of instantaneous quantities and overall energy consumption.
2010-10-25
Technical Paper
2010-01-2143
Prasad Shingne, Dennis N. Assanis, Aristotelis Babajimopoulos, Philip Keller, David Roth, Michael Becker
Naturally aspirated HCCI operation is typically limited to medium load operation (∼ 5 bar net IMEP) by excessive pressure rise rate. Boosting can provide the means to extend the HCCI range to higher loads. Recently, it has been shown that HCCI can achieve loads of up to 16.3 bar of gross IMEP by boosting the intake pressure to more than 3 bar, using externally driven compressors. However, investigating HCCI performance over the entire speed-load range with real turbocharger systems still remains an open topic for research. A 1 - D simulation of a 4 - cylinder 2.0 liter engine model operated in HCCI mode was used to match it with off-the-shelf turbocharger systems. The engine and turbocharger system was simulated to identify maximum load limits over a range of engine speeds. Low exhaust enthalpy due to the low temperatures that are characteristic of HCCI combustion caused increased back-pressure and high pumping losses and demanded the use of a small and more efficient turbocharger.
2010-10-25
Journal Article
2010-01-2142
Rick Dehner, Ahmet Selamet, Philip Keller, Michael Becker
The behavior of the compression system in turbochargers is studied with a one-dimensional engine simulation code. The system consists of an upstream compressor duct open to ambient, a centrifugal compressor, a downstream compressor duct, a plenum, and a throttle valve exhausting to ambient. The compression system is designed such that surge is the low mass flow rate instability mode, as opposed to stall. The compressor performance is represented through an extrapolated steady-state map. Instead of incorporating a turbine into the model, a drive torque is applied to the turbocharger shaft for simplification. Unsteady compression system mild surge physics is then examined computationally by reducing the throttle valve diameter from a stable operating point. Such an increasing resistance decreases the mass flow rate through the compression system and promotes surge.
2010-10-25
Journal Article
2010-01-2245
Michele Battistoni, Carlo Nazareno Grimaldi
The aim of the paper is the comparison of the injection process with different fuels, i.e. a standard diesel fuel and a pure biodiesel. Multiphase cavitating flows inside diesel nozzles are analyzed by means of unsteady CFD simulations using a two-fluid approach with consideration of bubble dynamics, on moving grids from needle opening to closure. Two five-hole nozzles with cylindrical and conical holes are studied and their behaviors are discussed taking into account the different properties of the two fuels. Extent of cavitation regions is not much affected by the fuel type. Biodiesel leads to significantly higher mass flow only if the nozzle design induces significant cavitation which extends up to the outlet section and if the injector needle is at high lift. If the internal hole shaping is able to suppress cavitation, the stabilized mass flows are very similar with both fuels.
2010-10-25
Technical Paper
2010-01-2244
Lucio Postrioti, Michele Battistoni
In the present paper, a detailed numerical and experimental analysis of a spray momentum flux measurement device capability is presented. Particular attention is devoted to transient, engine-like injection events in terms of spray momentum flux measurement. The measurement of spray momentum flux in steady flow conditions, coupled with knowledge of the injection rate, is steadily used to estimate the flow mean velocity at the nozzle exit and the extent of flow cavitation inside the nozzle in terms of a velocity reduction coefficient and a flow section reduction coefficient. In the present study, the problem of analyzing spray evolution in short injection events by means of jet momentum flux measurement was approached. The present research was based on CFD-3D analysis of the spray-target interaction in a momentum measurement device.
2010-10-25
Technical Paper
2010-01-2240
Maria Cárdenas, Diana Martin, Reinhold Kneer
An experimental study on the interaction of sprays from clustered orifices is presented. Droplet size and velocity information has been gained by means of Phase Doppler Anemometry for different nozzle configurations varying the diverging opening angle between clustered sprays from 0° to 15°. These nozzles were investigated under high-pressure (50 bar) and high-temperature (800 K) conditions in a pressure chamber and the results are compared to two standard nozzles with flow rates corresponding either to the flow rate of the cluster nozzle configuration or half of the flow rate of this configuration. Two injection pressures, 600 bar and 1100 bar, were used to investigate all nozzles. This investigation completes the characterization of sprays from the cluster nozzles presented in an earlier work. Findings obtained therein were used to choose the measurement procedure for the present investigation and also to determine the spray width in order to obtain the spray angle.
2010-10-25
Technical Paper
2010-01-2247
Cyril Crua, Tenzin Shoba, Morgan Heikal, Martin Gold, Cassandra Higham
The formation and breakup of diesel sprays was investigated experimentally on a common rail diesel injector using a long range microscope. The objectives were to further the fundamental understanding of the processes involved in the initial stage of diesel spray formation. Tests were conducted at atmospheric conditions and on a rapid compression machine with motored in-cylinder peak pressures up to 8 MPa, and injection pressures up to 160 MPa. The light source and long range imaging optics were optimized to produce blur-free shadowgraphic images of sprays with a resolution of 0.6 μm per pixel, and a viewing region of 768x614 μm. Such fine spatial and temporal resolutions allowed the observation of previously unreported shearing instabilities and stagnation point on the tip of diesel jets.
2010-10-25
Technical Paper
2010-01-2271
Stephen Busch, Christian Disch, Heiko Kubach, Ulrich Spicher
Investigations of the fuel injection processes in a spark ignition direct injection engine have been performed for two different fuels. The goal of this research was to determine the differences between isooctane, which is often used as an alternative to gasoline for optical engine investigations, and a special, non-fluorescing, full boiling range multicomponent fuel. The apparent vaporization characteristics of isooctane and the multicomponent fuel were examined in homogeneous operating mode with direct injection during the intake stroke. To this end, simultaneous Mie scattering and planar laser induced fluorescence imaging experiments were performed in a transparent research engine. Both fuels were mixed with 3-Pentanone as a fluorescence tracer. A frequency-quadrupled Nd:YAG laser was used as both the fluorescent excitation source and the light scattering source.
2010-10-25
Technical Paper
2010-01-2268
Jun Deng, Chunwang Li, Zongjie Hu, Zhijun Wu, Liguang Li
Biodiesel has been paid more and more attention as a renewable fuel due to some excellent properties such as renewable, high cetane number, ultralow sulfur content, no aromatic hydrocarbon, high flash point, low CO2 emission when compared with diesel. While others physical properties like high viscosity, high surface tension, big density and bad volatility would spoil the spray characteristics of biodiesel fuel, which will affect the thermal efficiency when running in diesel engine. Accompanied with constant volume vessel and high speed video camera system, a high pressure common rail system, which could provide an injection pressure of 180 MPa, is used to investigate the characteristics of jatropha curcas biodiesel, palm oil biodiesel and diesel fuel. The effects of injection pressures and ambient densities on spray characteristics of these fuels are studied.
2010-10-25
Technical Paper
2010-01-2274
Hajime Fujimoto
The premixed charge compression ignition (PCCI) combustion in a compression ignition (Cl) engine is one of countermeasures against the very much severe regulation for exhaust gas of engine out. The authors have been proposed to use the fuel mixed with high volatility component and low volatility component to actualize PCCI combustion. This kind of fuel injected forms a fine and lean spray by the flash boiling phenomena which depends on the pressure and the temperature. The role of the former fuel is to decrease in the generation of particulate matters (PM) and that of the latter one is to break out the ignition. Thus, it is very much significant to find the distribution of vapor concentration of both fuels in a spray. This paper describes both distributions in a single diesel spray by use of the technique of laser induced fluorescence (LIF) in a constant volume chamber with high temperature at high pressure as the fundamental research.
2010-10-25
Technical Paper
2010-01-2163
Kaname Naganuma, Yasuo Takagi, Atsuhiro Kawamura, Yoshio Sato
Hydrogen engines are required to provide high thermal efficiency and low nitrogen oxide (NOX) emissions. There are many possible combinations of injection timing, ignition timing, lambda and EGR rate that can be used in a direct-injection system for achieving such performance. In this study, NOX emissions of natural aspirated 4 cylinders engine with management strategies involving the injection timing, ignition timing, lambda and the EGR rate were evaluated under a Japanese JE05 emissions test cycle. Finally, the paper projects the potential of direct injection hydrogen engine for obtaining high output power and attaining low NOX emissions of 0.7 g/kWh under the emission test cycle.
2010-10-25
Journal Article
2010-01-2164
Yi Yang, John E. Dec, Nicolas Dronniou, Blake Simmons
Long chain alcohols possess major advantages over the currently used ethanol as bio-components for gasoline, including higher energy content, better engine compatibility, and less water solubility. The rapid developments in biofuel technology have made it possible to produce C 4 -C 5 alcohols cost effectively. These higher alcohols could significantly expand the biofuel content and potentially substitute ethanol in future gasoline mixtures. This study characterizes some fundamental properties of a C 5 alcohol, isopentanol, as a fuel for HCCI engines. Wide ranges of engine speed, intake temperature, intake pressure, and equivalence ratio are investigated. Results are presented in comparison with gasoline or ethanol data previously reported. For a given combustion phasing, isopentanol requires lower intake temperatures than gasoline or ethanol at all tested speeds, indicating a higher HCCI reactivity.
2010-04-12
Technical Paper
2010-01-0568
Riccardo Ceccarelli, Philippe Moulin, Carlos Canudas de Wit
In nowadays diesel engine, the turbocharger system plays a very important role in the engine functioning and any loss of the turbine efficiency can lead to driveability problems and the increment of emissions. In this paper, a VGT turbocharger fault detection system is proposed. The method is based on a physical model of the turbocharger and includes an estimation of the turbine efficiency by a nonlinear adaptive observer. A sensitivity analysis is provided in order to evaluate the impact of different sensors fault, (drift and bias), used to feed the observer, on the estimation of turbine efficiency error. By the means of this analysis a robust variable threshold is provided in order to reduce false detection alarm. Simulation results, based on co-simulation professional platform (AMEsim© and Simulink©), are provided to validate the strategy.
2010-04-12
Technical Paper
2010-01-0595
Qianwang Fan, Zongjie Hu, Jun Deng, Liguang Li, Yi You, Jingyan Hu
This paper presents the simulation of in-cylinder stratified mixture formation, spray motion, combustion and emissions in a four-stroke and four valves direct injection spark ignition (DISI) engine with a pent-roof combustion chamber by the computational fluid dynamics (CFD) code. The Extended Coherent Flame Combustion Model (ECFM), implemented in the AVL-Fire codes, was employed. The key parameters of spray characteristics related to computing settings, such as skew angle, cone angle and flow per pulse width with experimental measurements were compared. The numerical analysis is mainly focused on how the tumble flow ratio and geometry of piston bowls affect the motion of charge/spray in-cylinder, the formation of stratified mixture and the combustion and emissions (NO and CO₂) for the wall-guided stratified-charge spark-ignition DISI engine.
2010-04-12
Journal Article
2010-01-0598
Walter F. Piock, Peter Weyand, Edgard Wolf, Volker Heise
The success of stratified combustion is strongly determined by the injection and ignition system used. A large temporal and spatial variation of the main parameters - mixture composition and charge motion - in the vicinity of the spark location are driving the demands for significantly improved ignition systems. Besides the requirements for conventional homogeneous combustion systems higher ignition energy and breakdown voltage capability is needed. The spark location or spark plug gap itself has to be open and well accessible for the mixture to allow a successful flame kernel formation and growth into the stratified mixture regime, while being insensitive to potential interaction with liquid fuel droplets or even fuel film. For this purpose several different ignition concepts are currently being developed. The present article will give an ignition system overview for stratified combustion within Delphi Powertrain Systems.
2010-04-12
Technical Paper
2010-01-0580
Richard Stone, Huayong Zhao, Lei Zhou
A single-cylinder Gasoline Direct Injection Engine (GDI) engine with a centrally mounted spray-guided injection system (150 bar fuel pressure) has been operated with stoichiometric and rich mixtures. The base fuel was 65% iso-octane and 35% toluene; hydrogen was aspirated into a plenum in the induction system, and its equivalence ratios were set to 0, 0.02, 0.05 and 0.1. Ignition timing sweeps were conducted for each operating point. Combustion was speeded up by adding hydrogen as expected. In consequence the MBT ignition advance was reduced, as were cycle-by-cycle variations in combustion. Adding hydrogen led to the expected reduction in IMEP as the engine was operated at a fixed manifold absolute pressure (MAP). An engine model has also been set up using WAVE. Particulate Matter (PM) emissions were measured with a Cambustion DMS500 particle sizer.
2010-04-12
Journal Article
2010-01-0585
Paul Whitaker, Yuan Shen, Christian Spanner, Heribert Fuchs, Apoorv Agarwal, Kevin Byrd
Gasoline turbocharged direct injection (GTDI) engines, such as EcoBoost™ from Ford, are becoming established as a high value technology solution to improve passenger car and light truck fuel economy. Due to their high specific performance and excellent low-speed torque, improved fuel economy can be realized due to downsizing and downspeeding without sacrificing performance and driveability while meeting the most stringent future emissions standards with an inexpensive three-way catalyst. A logical and synergistic extension of the EcoBoost™ strategy is the use of E85 (approximately 85% ethanol and 15% gasoline) for knock mitigation. Direct injection of E85 is very effective in suppressing knock due to ethanol's high heat of vaporization - which increases the charge cooling benefit of direct injection - and inherently high octane rating. As a result, higher boost levels can be achieved while maintaining optimal combustion phasing giving high thermal efficiency.
2010-04-12
Journal Article
2010-01-0590
John E. Kirwan, Mark Shost, Gregory Roth, James Zizelman
Today turbo-diesel powertrains offering low fuel consumption and good low-end torque comprise a significant fraction of the light-duty vehicle market in Europe. Global CO₂ regulation and customer fuel prices are expected to continue providing pressure for powertrain fuel efficiency. However, regulated emissions for NO and particulate matter have the potential to further expand the incremental cost of diesel powertrain applications. Vehicle segments with the most cost sensitivity like compacts under 1400 kg weight look for alternatives to meet the CO₂ challenge but maintain an attractive customer offering. In this paper the concepts of downsizing and downspeeding gasoline engines are explored while meeting performance needs through increased BMEP to maintain good driveability and vehicle launch dynamics. A critical enabler for the solution is adoption of gasoline direct injection (GDi) fuel systems.
2010-04-12
Technical Paper
2010-01-0588
David B. Roth, Philip Keller, Michael Becker
It has been clearly demonstrated separately, that the application of both Dual Cam Phasers (DCP) and External Cooled EGR systems are highly beneficial to improving the efficiency of highly-boosted GDI engines. DCP systems can optimize the volumetric efficiency at WOT conditions, improve boost and transient response at low engine speeds, and provide internal EGR at low RPM part-load conditions. External cooled EGR has been demonstrated to dramatically improve the fuel consumption, lower turbine inlet temperature, and improve emissions at high power conditions. In previous investigations by the BorgWarner Engine Systems Group, we showed that full engine speed/load range EGR coverage can be obtained by combining High Pressure Loop and Low Pressure Loop external EGR systems with a DCP strategy.
Viewing 1 to 30 of 14431

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