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Viewing 271 to 300 of 22533
2014-04-01
Technical Paper
2014-01-1382
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco
Abstract The objective of this paper is the evaluation of the effect of the fuel properties and the comparison of a PFI and GDI injection system on the performances and on particle emission in a Spark Ignition engine. Experimental investigation was carried out in a small single cylinder engine for two wheel vehicles. The engine displacement was 250 cc. It was equipped with a prototype GDI head and also with an injector in the intake manifold. This makes it possible to run the engine both in GDI and PFI configurations. The engine was fuelled with neat gasoline and ethanol, and ethanol/gasoline blends at 10% v/v, 50% v/v and 85% v/v. The engine was equipped of a quartz pressure transducer that was flush-mounted in the region between intake and exhaust valves. Tests were carried out at 3000 rpm and 4000 rpm full load and two different lambda conditions. These engine points were chosen as representative of urban driving conditions.
2014-04-01
Technical Paper
2014-01-1400
Nicholas Gysel, George Karavalakis, Thomas Durbin, Debra Schmitz, Arthur Cho
Abstract The primary objective of this study was to evaluate the impact of three different biodiesel feedstocks on emissions compared to a baseline CARB ULSD with two heavy-duty trucks equipped with and without aftertreatment technologies. The biodiesels included a soybean oil methyl ester (SME), a waste cooking oil methyl ester (WCO), and a methyl ester obtained from animal fat (AFME), blended at a 50% level by volume with the CARB diesel. The vehicles were equipped with a 2010 Cummins ISX-15 engine with a selective catalytic reduction (SCR), diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) and with a 2002 Cummins ISX-450 engine. Both vehicles were tested over the Urban Dynamometer Driving Schedule (UDDS) on a heavy-duty chassis dynamometer. For this study, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), total hydrocarbons (THC), methane (CH4), non-methane hydrocarbons (NMHC), and particulate matter (PM) were measured.
2014-04-01
Technical Paper
2014-01-1396
Harveer Singh Pali, Naveen Kumar, Chinmaya Mishra
Abstract In the present study, ethanol was added in lower proportions to non-edible vegetable oil “Schleichera oleosa” or “Kusum”, to evaluate various performance and emission characteristics of a single cylinder; diesel engine. For engine's trial, four samples were prepared with 5%, 10%, 15% and 20% ethanol in kusum oil (v/v) and the blends were named as E5K95, E10K90, E15K85 and E20K80 respectively. Neat Kusum oil was named as K100. The results indicated that brake thermal efficiency (BTE) was found to increase with increase in volume fraction of ethanol in the kusum oil. E5K95, E10K90, E15K85 and E20K80 test fuels exhibited maximum BTE of 25.4%, 26.4%, 27.4% and 27.7% respectively as compared to 23.6% exhibited by the neat Kusum oil. Similarly, full load brake specific energy consumption (BSEC) decreased from 16.3MJ/kWh in case of neat Kusum oil to 15.1MJ/kWh for E20K80 with an almost linear reduction pattern with increased ethanol composition in the test fuel.
2014-04-01
Journal Article
2014-01-1397
S.M. Remmert, R.F. Cracknell, R. Head, A. Schuetze, A.G.J. Lewis, S. Akehurst, J.W.G. Turner, A. Popplewell
Increasingly strict government emissions regulations in combination with consumer demand for high performance vehicles is driving gasoline engine development towards highly downsized, boosted direct injection technologies. In these engines, fuel consumption is improved by reducing pumping, friction and heat losses, yet performance is maintained by operating at higher brake mean effective pressure. However, the in-cylinder conditions of these engines continue to diverge from traditional naturally aspirated technologies, and especially from the Cooperative Fuels Research engine used to define the octane rating scales. Engine concepts are thus key platforms with which to screen the influence of fundamental fuel properties on future engine performance.
2014-04-01
Technical Paper
2014-01-1394
Dai Liu, Hongming Xu, Ramadhas Arumugam Sakunthalai
Abstract Biodiesel is an oxygenated alternative fuel made from vegetable oils and animal fats via transesterification and the feedstock of biodiesel is diverse and varies between the local agriculture and market scenarios. Use of various feedstock for biodiesel production result in variations in the fuel properties of biodiesel. In this study, biodiesels produced from a variety of real world feedstock was examined to assess the performance and emissions in a light-duty engine. The objective was to understand the impact of biodiesel properties on engine performances and emissions. A group of six biodiesels produced from the most common feedstock blended with zero-sulphur diesel in 10%, 30% and 60% by volume are selected for the study. All the biodiesel blends were tested on a light-duty, twin-turbocharged common rail V6 engine. Their gaseous emissions (NOx, THC, CO and CO2) and smoke number were measured for the study.
2014-04-01
Technical Paper
2014-01-1393
Mohammed Moore Ojapah, Hua Zhao, Yan Zhang
Abstract In recent years, in order to develop more efficient and cleaner gasoline engines, a number of new engine operating strategies have been proposed and many have been studied on different engines but there is a lack of comparison between various operating strategies and alternative fuels at different SI modes. In this research, a single cylinder direct injection gasoline engine equipped with an electro-hydraulic valve train system has been commissioned and used to study and compare different engine operation modes. In this work, the fuel consumption, gaseous and particulate emissions of gasoline and its mixture with ethanol (E15 and E85) were measured and analysed when the engine was operated at the same load but with different load control methods by an intake throttle, reduced intake valve duration, and positive overlap.
2014-04-01
Technical Paper
2014-01-1370
Cheng Tan, Hongming Xu, He Ma, Akbar Ghafourian
Abstract Transient operation is frequently used by vehicle engines and the exhaust emissions from the engine are mostly higher than those under the steady station. An experimental study has been conducted to investigate the effect of various valve timings and spark timings on combustion characteristics and particle emissions from a modern 3.0-liter Gasoline Direct Injection (GDI) passenger car engine. The transient condition was simulated by load increase from 5% to 15% at a constant engine speed with different settings of valve timings and spark timings. The transient particle emission measurement was carried out by a Cambustion DMS500 particulate analyser. The combustion characteristics of the engine during transient operation including cycle-by-cycle combustion variations were analyzed. The time-resolved particle number, particulate mass and particle size distribution were compared and analyzed between different engine settings.
2014-04-01
Journal Article
2014-01-1373
Xi Luo, Xin Yu, Kan Zha, Marcis Jansons, Valentin Soloiu
Emissions of Unburned Hydrocarbons (UHC) from diesel engines are a particular concern during the starting process, when after-treatment devices are typically below optimal operating temperatures. Drivability in the subsequent warm-up phase is also impaired by large cyclic fluctuations in mean effective pressure (MEP). This paper discusses in-cylinder wall temperature influence on unburned hydrocarbon emissions and combustion stability during the starting and warm-up process in an optical engine. A laser-induced phosphorescence technique is used for quantitative measurements of in-cylinder wall temperatures just prior to start of injection (SOI), which are correlated to engine out UHC emission mole fractions and combustion phasing during starting sequences over a range of charge densities, at a fixed fueling rate. Squish zone cylinder wall temperature shows significant influence on engine out UHC emissions during the warm-up process.
2014-04-01
Journal Article
2014-01-1366
Kevin Cedrone, Wai K. Cheng
The engine and its exhaust flow behaviors are investigated in a turbo-charged gasoline direct injection engine under simulated cold-fast-idle condition. The metrics of interest are the exhaust sensible and chemical enthalpy flows, and the exhaust temperature, all of which affect catalyst light off time. The exhaust sensible enthalpy flow is mainly a function of combustion phasing; the exhaust chemical enthalpy flow is mainly a function of equivalence ratio. High sensible and chemical enthalpy flow with acceptable engine stability could be obtained with retarded combustion and enrichment. When split injection is employed with one early and one later and smaller fuel pulse, combustion retards with early secondary injection in the compression stroke but advances with late secondary injection. Comparing gasoline to E85, the latter produces a lower exhaust temperature because of charge cooling effect and because of a faster combustion.
2014-04-01
Journal Article
2014-01-1367
David Heuwetter, William Glewen, David E. Foster, Roger Krieger, Michael Andrie
The transient response of an engine with both High Pressure (HP) and Low Pressure (LP) EGR loops was compared by conducting step changes in EGR fraction at a constant engine speed and load. The HP EGR loop performance was shown to be closely linked to turbocharger performance, whereas the LP EGR loop was relatively independent of turbocharger performance and vice versa. The same experiment was repeated with the variable geometry turbine vanes completely open to reduce turbocharger action and achieve similar EGR rate changes with the HP and LP EGR loops. Under these conditions, the increased loop volume of the LP EGR loop prolonged the response of intake O2 concentration following the change in air-fuel ratio. The prolonged change of intake O2 concentration caused emissions to require more time to reach steady state as well. Strong coupling between the HP EGR loop and turbochargers was again observed using a hybrid EGR strategy.
2014-04-01
Journal Article
2014-01-1368
Justin E. Ketterer, Wai K. Cheng
Abstract Particulate emissions from a production gasoline direct injection spark ignition engine were studied under a typical cold-fast-idle condition (1200 rpm, 2 bar NIMEP). The particle number (PN) density in the 22 to 365 nm range was measured as a function of the injection timing with single pulse injection and with split injection. Very low PN emissions were observed when injection took place in the mid intake stroke because of the fast fuel evaporation and mixing processes which were facilitated by the high turbulent kinetic energy created by the intake charge motion. Under these conditions, substantial liquid fuel film formation on the combustion chamber surfaces was avoided. PN emissions increased when injection took place in the compression stroke, and increased substantially when the fuel spray hit the piston.
2014-04-01
Technical Paper
2014-01-1380
Christian Lohfink, Dennis Wiese, Wolfgang Reiser
Abstract Although in the European Union in general no metal containing additives are used, in 2009 a limitation of manganese in gasoline fuel up to 6 mg manganese per liter was introduced in the revised Fuels Quality Directive. In this paper the influences and risks of metal-based additives on the aging of exhaust system components were detected, using the example of the currently allowed manganese content of 6 mg per liter. The legislative endurance test, the Standard Road Cycle (SRC) over the useful life period of 160,000 km conforming to EC Regulation 692/2008 was used. Investigations were carried out with two endurance tests with metal-free-fueled and metal-containing-fueled (reference fuel plus metallic additive) vehicles on a certified chassis dynamometer. The two identical vehicles were both equipped with a typical state of the art downsized DISI engine with Euro 5 application. Euro 5 reference fuel was used as base gasoline.
2014-04-01
Technical Paper
2014-01-1362
Zhiqiang Zhang, Fuquan Zhao, Liguang Li, Zhijun Wu, Jun Deng, Zongjie Hu
Abstract Based on high EGR rate, the low temperature combustion (LTC) has been studied widely, of which the application range is more extensive than the homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI). As the high EGR rate would influence the condition of intake charge, it would also affect the combustion process and the HC emissions, thus the combustion stability of LTC would be lower than tradition diesel combustion. In this study, an ion current detecting technology was employed to explore the ion current at different EGR rates. Meanwhile, the combustion parameters were also investigated, which included the in-cylinder pressure and heat release rate. The CA50 and CAI50 were adopted as the phases of combustion and ion current, which respectively represented the crank angle of mid-point for the integrated heat release and integrated ion current. Then the correlation between CA50 and CAI50 was analysed.
2014-04-01
Journal Article
2014-01-1355
Peter Fussey, David Limebeer
Setting up engines to meet emissions limits often involves extensive steady-state calibration activities combined with ad-hoc strategies to compensate for transient operation. As engines become more complex and acceptable emissions levels ever lower, this task is becoming increasingly time consuming and expensive. The inclusion of models in the engine control units offers a way to reduce some of this calibration effort. Model-based control is an active area of research with advanced approaches now being proposed. One example is the use of real-time models to regulate the burn angle during transient manœuvres. This paper describes the application of a control-orientated combustion model to control directly emissions during transients. The model is used to optimize and constrain the NOx emissions directly, rather than controlling an inferred variable such as the burn angle. This has the benefit that calibration engineers will be able to set the emissions trade-off directly.
2014-04-01
Technical Paper
2014-01-1356
Matteo De Cesare, Federico Stola, Cosimo Senni, Alfredo Di Monte, Stefano Sgatti
Abstract The Selective Catalytic Reduction (SCR) system, installed on the exhaust line, is currently widely used on Diesel heavy-duty trucks and it is considered a promising technique for Euro 6 compliancy for light and medium duty trucks and bigger passenger cars. Moreover, new more stringent emission regulations and homologation cycles are being proposed for Euro 6c stage and they are scheduled to be applied by the end of 2017. In this context, the interest for SCR technology and its application on light-duty trucks is growing, with a special focus on its potential benefit in term of fuel consumption reduction, thanks to combustion optimization. Nevertheless, the need to warm up the exhaust gas line, to meet the required NOx conversion efficiency, remains an issue for such kind of applications.
2014-04-01
Technical Paper
2014-01-1322
Valentin Soloiu, Alejandro Rivero-Castillo, Martin Muinos, Marvin Duggan, Spencer Harp, Wallace Peavy, Sven Wolter, Brian Vlcek
Abstract This study presents the combustion and emissions characteristics of Reactivity Controlled Combustion Ignition (RCCI) produced by early port fuel injection (PFI) of low reactivity n-butanol (normal butanol) coupled with in cylinder direct injection (DI) of cottonseed biodiesel in a diesel engine. The combustion and emissions characteristics were investigated at 5.5 bars IMEP at 1400 RPM. The baseline was taken from the combustion and emissions of ULSD #2 which had an ignition delay of 13° CAD or 1.5ms. The PFI of n-butanol and DI of cottonseed biodiesel strategy showed a shorter ignition delay of 12° CAD or 1.45ms, because of the higher CN of biodiesel. The combustion proceeded first by the ignition of the pilot (cottonseed biodiesel) BTDC that produced a premixed combustion phase, followed by the ignition of n-butanol that produced a second spike in heat release at 2° CAD ATDC.
2014-04-01
Technical Paper
2014-01-1329
Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco, Francesco Catapano
Abstract The use of methane as supplement to liquid fuel is one of the solution proposed for the reduction of the internal combustion engine pollutant emissions. Its intrinsic properties as the high knocking resistance and the low carbon content makes methane the most promising clean fuel. The dual fuel combustion mode allows improving the methane combustion acting mainly on the methane slow burning velocity and allowing lean burn combustion mode. An experimental investigation was carried out to study the methane-gasoline dual fuel combustion. Methane was injected in combustion chamber (DI fuel) while gasoline was injected in the intake manifold (PFI fuel). The measurements were carried out in an optically accessible small single-cylinder four-stroke engine. It was equipped with the cylinder head of a commercial 250 cc motorcycles engine representative of the most popular two-wheel vehicles in Europe.
2014-04-01
Technical Paper
2014-01-1342
Huayu Tian, Baigang Sun, Haichun Yao, Hongyang Tang, Qinghe Luo
Abstract Nowadays, the world is facing severe energy crisis and environment problems. Development of hydrogen fuel vehicles is one of the best ways to solve these problems. Due to the difficulties of infrastructures, such as the hydrogen transport and storage, hydrogen fuel vehicles have not been widely used yet. As a result, Hydrogen-gasoline dual-fuel vehicle is a solution as a compromise. In this paper, three way catalytic converter (TWC) was used to reduce emissions of hydrogen-gasoline dual-fuel vehicles. On wide open throttle and load characteristics, the conversion efficiency of TWC in gasoline engine was measured. Then the TWC was connected to a hydrogen internal combustion engine. After switching the hydrogen and gasoline working mode, emission data was measured. Experiment results show that the efficiency of a traditional TWC can be maintained above 85%., while it works in a hydrogen-gasoline dual-fuel alternative working mode.
2014-04-01
Technical Paper
2014-01-1308
Mufaddel Dahodwala, Satyum Joshi, Erik W. Koehler, Michael Franke
Abstract The advantages of applying Compressed Natural Gas (CNG) as a fuel for internal combustion engines are well known. In addition to a significant operating cost savings due to a lower fuel price relative to diesel, there is an opportunity to reduce the engine's emissions. With CNG combustion, some emissions, such as Particulate Matter (PM) and Carbon Dioxide (CO2), are inherently reduced relative to diesel fueled engines due to the nature of the combustion and the molecular makeup of the fuel. However, it is important to consider the impact on all emissions, including Total Hydrocarbons (THC) and Carbon Monoxide (CO), which can increase with the use of CNG. Nitrogen Oxides (NOx) emission is often reported to decrease with the use of CNG, but the ability to realize this benefit is significantly impacted by the control strategy and calibration applied. FEV has investigated the emissions and performance impact of operating a heavy-duty diesel engine with CNG in a dual fuel mode.
2014-04-01
Journal Article
2014-01-1306
Glenn Lucachick, Aaron Avenido, David Kittelson, William Northrop
Diesel low temperature combustion (LTC) is an operational strategy that is effective at reducing soot and oxides of Nitrogen (NOx) emissions at low engine loads in-cylinder. A downside to LTC in diesel engines is increased hydrocarbon (HC) emissions. This study shows that semi-volatile species from LTC form the bulk of particulate matter (PM) upon dilution in the atmosphere. The nature of gas-to-particle conversion from high HC operating modes like LTC has not been well characterized. In this work, we explore engine-out PM and HC emissions from LTC and conventional diffusion combustion (CC) operation for two different engine load and speed modes using a modern light-duty diesel engine. An experimental method to investigate PM volatility was implemented. Raw exhaust was diluted under two dilution conditions. A tandem differential mobility analyzer (TDMA) was used to identify differences in volatility between particle sizes.
2014-04-01
Technical Paper
2014-01-1307
Xiao Ma, Yunliang Qi, Zhi Wang, Hongming Xu, Jian-Xin Wang
Abstract Using EGR instead of throttle to control the load of a stoichiometric dual-fuel dieseline (diesel and gasoline) compression ignition (SDCI) engine with three-way catalyst (TWC) aftertreatment is considered a promising technology to address the challenges of fuel consumption and emissions in future internal combustion engines. High-speed imaging is used to record the flame signal in a single-cylinder optical engine with a PFI+DI dual injection system. The premixed blue flame is identified and separated using green and blue channels in RGB images. The effects of injection timing on SDCI combustion are studied. An earlier injection strategy is found to be ideal for soot reduction; however, the ignition-injection decoupling problem results in difficulties in combustion control. It is also found that a split injection strategy has advantages in soot reduction and thermal efficiency.
2014-04-01
Journal Article
2014-01-1313
Nicolas Dronniou, Julian Kashdan, Bertrand Lecointe, Kyle Sauve, Dominique Soleri
Abstract Dual-fuel combustion strategies combining a premixed charge of natural gas and a pilot injection of diesel fuel offer the potential to reduce CO2 emissions as a result of the high Hydrogen/Carbon (H/C) ratio of methane gas. Moreover, the high octane number of methane means that dual-fuel combustion strategies can be employed on compression ignition engines without the need to vary the engine compression ratio, thereby significantly reducing the cost of engine hardware modifications. The aim of this investigation is to explore the fundamental combustion phenomena occurring when methane is ignited with a pilot injection of diesel fuel. Experiments were performed on a single-cylinder optical research engine which is typical of modern, light-duty diesel engines. A high-speed digital camera recorded time-resolved combustion luminosity and an intensified CCD camera was used for single-cycle OH*chemiluminescence imaging.
2014-04-01
Technical Paper
2014-01-1311
Debabrata Barik, Murugan Sivalingam
Abstract The present study was aimed to run the diesel engine only with two renewable fuels in a dual fuel mode. The karanja methyl ester (KME) derived from karanja oil was used as an injected fuel, and the biogas obtained from the anaerobic digestion of pongamia pinnata (Karanja) de-oiled cakes, was used as a secondary fuel in a single cylinder, four stroke, air cooled, direct injection (DI) diesel engine. Four different flow rates of biogas, viz., 0.3 kg/h, 0.6 kg/h, 0.9 kg/h and 1.2 kg/h were inducted along with the air in the suction of the engine. The results of the experiment were compared with those of diesel and KME operations. Biogas inducted at a flow rate of 0.9 kg/h was found to be the best among all the flow rates, in terms of the performance and emission of the engine. The dual fuel operation showed a higher BSEC than that of diesel operation at full load.
2014-04-01
Technical Paper
2014-01-1317
Hassan Ali Khairallah, Umit Koylu
Abstract During the past decade, considerable efforts have been made to introduce alternative fuels for use in conventional diesel and gasoline engines. There is significant interest in adding hydrogen to a diesel engine to reduce emissions and improve efficiency. With the rapid increase in computational capabilities, computational fluid dynamics (CFD) codes have become essential tools for the design, control, and optimization of dual fuel engines. In the present study, a reduced chemical kinetics mechanism, consisting of 52 reactions and 29 chemical species for n-heptane fuel combustion, was incorporated with detailed chemical kinetics consisting of 29 reactions for hydrogen including additional nitrogen oxidation. This reaction mechanism was coupled with a 3D CFD model based on AVL FIRE software to investigate the performance and emission characteristics of a diesel engine with low amounts of hydrogen addition.
2014-04-01
Technical Paper
2014-01-1292
Yuwei Zhao, Ying Wang, Shenghua Liu
Abstract Premixed charge compression ignition (PCCI) combustion has been shown to be a promising combustion technique to improve the combustion process and simultaneously reduce both Nitrogen oxides (NOx) and particulate matter (PM) emissions. The combination of port dimethyl ether (DME) induction and in-cylinder diesel direct-injection compression ignition (DICI) combustion was studied in a YTR 2105 engine. The main purposes of this paper were to investigate the effects of DME introduction on the combustion and emission characteristics of a diesel engine. Results obtained revealed that PCCI combustion process was composed of the homogeneous charge compression ignition (HCCI) combustion and conventional diffusion combustion. As the DME quantity was increased, the start of combustion (SOC) was advanced. The peak values of in-cylinder pressure and mass averaged temperature increased as well as the maximum heat release rate of DME HCCI combustion.
2014-04-01
Journal Article
2014-01-1296
Yizhou Zhang, Jaal Ghandhi, David Rothamer
Abstract Comparison of particulate size distribution measurements from different combustion strategies was conducted with a four-stroke single-cylinder diesel engine. Measurements were performed at four different load-speed points with matched combustion phasing. Particle size distributions were measured using a scanning mobility particle sizer (SMPS). To study the influence of volatile particles, measurements were performed with and without a volatile particle remover (thermodenuder) at low and high dilution ratios. The use of a single testing platform enables quantitative comparison between combustion strategies since background sources of particulate are held constant. A large number of volatile particles were present under low dilution ratio sample conditions for most of the operating conditions. To avoid the impact of volatile particles, comparisons were made based on the high dilution ratio measurements with the thermodenuder.
2014-04-01
Technical Paper
2014-01-1298
Tadanori Yanai, Xiaoye Han, Meiping Wang, Graham T. Reader, Ming Zheng, Jimi Tjong
Abstract The study investigated the characteristics of the combustion, the emissions and the thermal efficiency of a direct injection diesel engine fuelled with neat n-butanol. Engine tests were conducted on a single cylinder four-stroke direct injection diesel engine. The engine ran at 6.5 bar IMEP and 1500 rpm engine speed. The intake pressure was boosted to 1.0 bar (gauge), and the injection pressure was controlled at 60 or 90 MPa. The injection timing and the exhaust gas recirculation (EGR) rate were adjusted to investigate the engine performance. The effect of the engine load on the engine performance was also investigated. The test results showed that the n-butanol fuel had significantly longer ignition delay than that of diesel fuel. n-Butanol generally led to a rapid heat release pattern in a short period, which resulted in an excessively high pressure rise rate. The pressure rise rate could be moderated by retarding the injection timing and lowering the injection pressure.
2014-04-01
Journal Article
2014-01-1101
Arnon Poran, Moris Artoul, Moshe Sheintuch, Leonid Tartakovsky
This paper describes a model for the simulation of the joint operation of internal combustion engine (ICE) with methanol reformer when the ICE is fed by the methanol steam reforming (SRM) products and the energy of the exhaust gases is utilized to sustain endothermic SRM reactions. This approach enables ICE feeding by a gaseous fuel with very favorable properties, thus leading to increase in the overall energy efficiency of the vehicle and emissions reduction. Previous modeling attempts were focused either on the performance of ICE fueled with SRM products or on the reforming process simulation and reactor design. It is clear that the engine performance is affected by the composition of the reforming products and the reforming products are affected by the exhaust gas temperature, composition and flow rate.
2014-04-01
Technical Paper
2014-01-1124
Raouf Mobasheri, Seyed Alireza Khabbaz
Abstract Exhaust Gas Recirculation (EGR) is an effective pre-treatment technique, which has been widely used to decrease the amount of the oxides of nitrogen (NOx) emission from diesel engines. However, the use of high EGR rates leads to the reduction in oxygen availability in the burning regions of the combustion chamber which impairs the soot oxidation process. Consequently, higher soot generated by EGR leads to long-term usage problems inside the engines such as higher carbon deposits, lubricating oil degradation and enhanced engine wear. In this study, CFD modeling has been carried out to analyze the effects of high EGR rates in conjunction with optimum multiple injection strategies. A heavy-duty DI Diesel engine has been modeled to study the engine performance and emissions with various EGR rates (from 0% to 40%). The selected operating points have been achieved with the same injection profile including a main and post injection for all considered cases.
2014-04-01
Technical Paper
2014-01-1071
Haichun Yao, Baigang Sun, Huayu Tian, Qinghe Luo, Hongyang Tang
Abstract NOx are the only harmful emissions of hydrogen internal combustion engine. EGR is one of the effective methods to reduce NOx. The traditional EGR is not suitable for hydrogen internal combustion engine. Therefore, the study of influence of hot EGR on hydrogen internal combustion engine is important. A 2.0L hydrogen internal combustion engine with hot EGR system model is employed to optimize the diameter and position of hot EGR based on a simulation analysis. The result shows that both of the combustion temperature and NOx increase as EGR increases due to the rise of intake temperature for low load condition, for heavy load, with the increase of EGR rate, NOx emissions decreases slightly before the mixture equivalence ratio comes to 1and then dropped significantly after the mixture equivalence ratio greater than 1. Unburned hydrogen in TWC has the effect of reducing NOx after catalysts decrease largely.
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