Criteria

Display:

Results

Viewing 31 to 60 of 22470
2014-10-13
Technical Paper
2014-01-2674
Gerardo Valentino, Stefano Iannuzzi
The use of biodiesel or oxygenated fuels from renewable sources in diesel engines is of particular interest because of the low environmental impact that can be achieved. The present paper reports results of an experimental investigation performed on a light duty diesel engine fuelled with biodiesel, gasoline and butanol mixed, at different volume fractions, with mineral diesel. The investigation was performed on a turbocharged DI four cylinder diesel engine for automotive applications equipped with a common rail injection system. Engine tests were carried out at 2500 rpm, 0.8 MPa of brake mean effective pressure selecting a single injection strategy and performing a parametric analysis on the effect of combustion phasing and oxygen concentration at intake on engine performance and exhaust emissions. The experiments demonstrated that the fuel properties have a strong impact on soot emissions. Blends composed of diesel-gasoline or diesel-butanol determined the maximum reduction in smoke emissions compared to the diesel fuel.
2014-10-13
Technical Paper
2014-01-2671
Wuqiang Long, Qiang Zhang, Jiangping Tian, Yicong Wang, Xiangyu Meng
Abstract To directly control the premixed combustion phasing, a novel method called Jet Controlled Compression Ignition (JCCI) is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine at 3000 r/min without EGR. Numerical model was validated by pressure and heat release rate curves at a fixed spark timing. The simulation results showed that the reacting active radical species with high temperature issued from ignition chamber played an important role on the onset of combustion in JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from ignition chamber. Consequently, the experiments of spark timing sweep were conducted to verify the above deduction. The results showed a good linear relationship between spark timing and CA10 and CA50, which validated the ability for direct combustion phasing control in diesel premixed combustion. The NOx and Soot emissions gradually changed with decrease of spark advance angle.
2014-10-13
Technical Paper
2014-01-2678
Buyu Wang, Shi-Jin Shuai, Hong-Qiang Yang, Zhi Wang, Jian-Xin Wang, Hongming Xu
Abstract A study of Multiple Premixed Compression Ignition (MPCI) with heavy naphtha is performed on a light-duty single cylinder diesel engine. The engine is operated at a speed of 1600rpm with the net indicated mean effective pressure (IMEP) from 0.5MPa to 0.9MPa. Commercial diesel is also tested with the single injection for reference. The combustion and emissions characteristics of the heavy naphtha are investigated by sweeping the first (−200 ∼ −20 deg ATDC) and the second injection timing (−5 ∼ 15 deg ATDC) with an injection split ratio of 50/50. The results show that compared with diesel combustion, the naphtha MPCI can reduce NOx, soot emissions and particle number simultaneously while maintaining or achieving even higher indicated thermal efficiency. A low pressure rise rate can be achieved due to the two-stage combustion character of the MPCI mode but with the penalty of high HC and CO emissions, especially at 0.5MPa IMEP. Attributed to the “spray- combustion- spray- combustion” process, the emissions can be controlled by adjusting the first and second injection timing, respectively.
2014-10-13
Technical Paper
2014-01-2675
Xiaobei Cheng, Shuai LI, Jin Yang, Shijun Dong, Zufeng Bao
PPCI in diesel engine is a combustion mode between conventional diesel combustion and homogeneous charge compression ignition (HCCI) combustion, which has the potential to simultaneously reduce NOX and soot emissions and improve thermal efficiency. N-butanol as a kind of clean and renewable biofuel can effectively prolong ignition delay and enhance fuel/air mixing because of their low cetane number, high volatility fuel characteristics, which make it a better alternative fuel to achieve PPCI. In this paper, PPCI combustion in a boosted four-cylinder diesel engine fueled with n-butanol-diesel blends is realized by adjusting injection timing and EGR rate based on single injection. The results show that both early and late injection have long premixed duration, which is helpful to form more homogeneous mixture, and no diffusion combustion is found in heat release rate curve. Premixed combustion and low temperature combustion are the key factors to reduce PM and NOX. With the increase of blending ratio, soot emission can maximumly be reduced by 70%, while NOX shows a slight increase at low load rate.
2014-10-13
Technical Paper
2014-01-2681
Zufeng Bao, Xiaobei Cheng, Liang Qiu, Xingcun Luan
The performance of Partially Premixed Combustion (PPC) relies heavily on the proper mixing between the injected fuel and the in-cylinder gas mixture. This pre-mixing aims to eliminate over-rich regions where the mixture forms soot, and at the same time to avoid the NOX formation region by lowering the combustion temperature by introduction of a large amount of EGR The main effort of this paper focuses on investigating the characteristic of PPC combustion and a suitable injection strategy for achieving the PPC combustion mode. Two injection strategies (i.e. double and single injection) were investigated on a four-cylinder heavy-duty diesel engine operating at low, medium and high load conditions. Injection timing, injection pressure, the pilot-main interval, the pilot injected fuel mass, the ratio between the two pilot injection pulses for the double pilot injection as well as the comparison of single injection mode and multi-injection mode in acquiring PPC was swept to study the combustion behavior in terms of combustion heat release, combustion phase, emissions and different efficiencies.
2014-10-13
Technical Paper
2014-01-2668
Maobin Liu, Bang-Quan He, Hua Zhao
Biobutanol, i.e. n-butanol, as a second generation bio-derived alternative fuel of internal combustion engines, can facilitate the energy diversification in transportation and reduce carbon dioxide (CO2) emissions from engines and vehicles. However, the majority of research was conducted on spark-ignition engines fuelled with n-butanol and its blend with gasoline. A few investigations were focused on the combustion and exhaust emission characteristics of homogeneous charge compression ignition (HCCI) engines fuelled with n-butanol-gasoline blends. In this study, experiments were conducted in a single cylinder four stroke port fuel injection HCCI engine with fully variable valve lift and timing mechanisms on both the intake and exhaust valves. HCCI combustion was achieved by employing the negative valve overlap (NVO) strategy while being fueled with gasoline (Bu0), n-butanol (Bu100) and their blends containing 30% n-butanol by volume (Bu30). The results indicate that, with the increase of n-butanol volume fraction in the blend, the autoignition timing advances and the combustion duration shortens, but indicated mean effective pressure (IMEP) decreases at the same conditions.
2014-10-13
Technical Paper
2014-01-2709
Xianjing Li, Liguang Li
Abstract Gasoline Direct Injection (GDI) engines have attracted interest as automotive power-plants because of their potential advantages in down-sizing, fuel efficiency and in emissions reduction. However, GDI engines suffer from elevated unburned hydrocarbon (HC) emissions during start up process, which are sometimes worsened by misfires and partial burns. Moreover, as the engine is cranked to idle speed quickly in HEVs (Hybrid Electric Vehicle), the transients of quick starts are more dramatically than that in traditional vehicle, which challenge the optimization of combustion and emissions. In this study, test bench had been set up to investigate the GDI engine performances for ISG (Integrated Starter and Generator) HEVs during start up process. Based on the test system, cycle-controlled of the fuel injection mass, fuel injection timing and ignition timing can be obtained, as well as the cycle-resolved measurement of the HC concentrations and NO emissions. This paper focus on the detailed effects of coolant temperature, fuel temperature, cranking speed, injection timing and total equivalence ratio on the combustion and emission characteristics of the GDI engine under stratified combustion condition during the engine quick start process cycle by cycle.
2014-10-13
Technical Paper
2014-01-2712
Dai Liu, Hongming Xu, Ramadhas Arumugam Sakunthalai, Jianyi Tian
Abstract Cold start is a critical operating condition for diesel engines because of the pollutant emissions produced by the unstable combustion and non-performance of after-treatment at lower temperatures. In this research investigation, a light-duty turbocharged diesel engine equipped with a common rail injection system was tested on a transient engine testing bed to study the starting process in terms of engine performance and emissions. The engine (including engine coolant, engine oil and fuel) was soaked in a cold cell at −7°C for at least 8 hours before starting the test. The engine operating parameters such as engine speed, air/fuel ratio, and EGR rate were recorded during the tests. Pollutant emissions (Hydrocarbon (HC), NOx, and particles both in mode of nucleation and accumulation) were measured before and after the Diesel Oxidation Catalyst (DOC). The results show that conversion efficiency of NOx was higher during acceleration period at −7°C start than the case of 20°C start.
2014-10-13
Technical Paper
2014-01-2714
Cheng Tan, Hongming Xu, He Ma, Jianyi Tian, Akbar Ghafourian
Abstract Automotive engines especially turbocharged diesel engines produce higher level of emissions during transient operation than in steady state. In order to improve understanding of the engine transients and develop advanced technologies to reduce the transient emissions, the engine researchers require accurate data acquisition and appropriate post-processing techniques which are capable of dealing with noise and synchronization issues. Four alternative automated methods namely FFT (Fast Fourier Transform), low-pass, linear and zero-phase filters were implemented on in-cylinder pressure. The data of each individual cycle was compared and analyzed for the suitability of combustion diagnostic. FFT filtering was the best suited method since it eliminated most pressure fluctuation and provided smooth rate of heat release profiles for each cycle. The outputs from the linear and zero-phase filters were close, but zero-phase filter had no phase distortion and eliminated the unwanted fluctuations more effectively.
2014-10-13
Technical Paper
2014-01-2727
Hu Li, Laura Campbell, Seyed Hadavi, Job Gava
Abstract Direct use of straight vegetable oil based biofuels in diesel engines without trans-esterification can deliver more carbon reductions compared to its counterpart biodiesel. However, the use of high blends of straight vegetable oils especially used cooking oil based fuels in diesel engines needs to ensure compatible fuel economy with PD (Petroleum Diesel) and satisfactory operational performance. There are two ways to use high blends of SVO (Straight Vegetable Oil) in diesel engines: fixed blending ratio feeding to the engine and variable blending ratio feeding to the engine. This paper employed the latter using an on-board blending system-Bioltec system, which is capable of heating the vegetable oils and feeding the engine with neat PD or different blends of vegetable oils depending on engine load and temperature. A used cooking oil derived SVO type of biofuel, the C2G Ultra Biofuel (C2G: Convert to Green), which is a fully renewable fuel made as a diesel replacement from processed used cooking oil, used directly in diesel engines specifically modified for this purpose, has been investigated in this research.
2014-10-13
Technical Paper
2014-01-2724
Pramod S. Mehta, Thangaraja Jeyaseelan
Abstract Biodiesel is an emerging alternative to fossil diesel for use in compression ignition engines. From environmental standpoint, an increase in nitric oxide (NO) emission from biodiesel fueled engine has been a major concern. Several investigations suggest the role of unsaturated methyl ester as a contributor to biodiesel-NO penalty. The chemical simplicity of biodiesel compared to fossil diesel makes their composition effects amenable to a systematic analysis. In this study, the effects of saturated palm and unsaturated karanja (Pongamia pinnata) biodiesels and their blends (Bio-mix) on compression ignition engine performance, combustion and NO emission are investigated. The combustion and emission characteristics of these fuels are compared with fossil diesel that the neat biodiesel fuels result in improved exhaust emissions except NO with a penalty in fuel economy. However, the use of biodiesel blends of palm and karanja resulted in reduction of the total unsaturated content to an extent of 40% relative to neat karanja.
2014-10-13
Technical Paper
2014-01-2689
Mohand Said Lounici, Khaled Loubar, Mohand Tazerout, Mourad Balistrou, Lyes Tarabet
Abstract The crude oil depletion, as well as aspects related to environmental pollution and global warming has caused researchers to seek alternative fuels. Biogas is one of the most attractive available fuels. It is of great interest both economically and ecologically. However, it faces problems that may compromise its industrial use. The dual-fuel engines have been investigated as a technique for the recovery of these gases and finding solutions to these problems. In the present work, performance and emissions of a direct injection diesel engine were first evaluated in conventional mode and dual fuel mode. The effect of biogas composition, based on methane content, is then examined. Also, dual fuel operation with regard to knock is investigated. The results show that, up to 95% of engine full load, the brake thermal efficiency (BTE) is lower in dual fuel mode. In terms of the specific consumption, although at high load the gap is much less, it is more significant in case of dual fuel mode.
2014-10-13
Technical Paper
2014-01-2693
Weifeng Li, Zhongchang Liu, Zhongshu Wang, Chao Li, Lianchao Duan, Hongbin Zuo
Abstract In recent years, strict emission regulations, the environmental awareness, and the high price of conventional fuels have led to the creation of incentive to promote alternative fuels. Among the alternative fuels, natural gas is very promising and highly attractive for its abundant resources, clean nature of combustion and low encouraging prices. But nitrogen oxides (NOx) emissions are still a problem in natural gas engines. In order to reduce NOx emissions, carbon dioxide (CO2), nitrogen (N2) and argon (Ar) were respectively introduced to dilute fuel-air mixtures in the cylinder. To this aim a 6.62 L, 6-cylinder, turbocharged, electronic controlled large-powered NG engine was subjected to a basic performance test to observe the effects of CO2, N2 and Ar on fuel economy and NOx emissions. During the test, the engine speed and torque were separately kept at 1450 r/min and 350 Nm. The results showed that the engine using Ar as dilution gas produced the highest thermal efficiency followed by N2 and then CO2 when NOx emissions were reduced to the same levels.
2014-10-13
Technical Paper
2014-01-2769
Paul Schaberg, Mark Wattrus
Abstract A study was performed to quantify the impact of blending Fatty Acid Methyl Ester (FAME) with Gas-to-Liquids (GTL) diesel fuel on engine exhaust emissions. Fuels that were considered in the study included blends of GTL and EN590 diesel containing 0, 7, and 20 volume % of Soy and Rapeseed Methyl Ester (SME and RME). Part of the study focused on European engine technology, and tests were performed on a Euro 3 passenger car engine and a Euro V heavy-duty engine. A limited study was performed using a heavy-duty engine meeting the US 2004 emission standards, in which case comparisons between the GTL diesel and FAME blends were made with US 2D and California Air Resources Board (CARB) reference fuels. The results showed particulate mass (PM) reductions to varying degrees with all of the GTL/FAME blends. The European heavy-duty engine showed a nominally neutral nitrogen oxides (NOx) emission response with the addition of FAME to either the EN590 or GTL diesel fuels, while an increase in NOx emissions was found with the US heavy-duty engine.
2014-10-13
Technical Paper
2014-01-2766
Gian Marques, Lian Izquierdo, Camila Coutinho
Abstract Bioethanol and plant oil-derived biodiesel are generally considered first generation biofuels. More sustainable and cost effective new biofuels are being designed and produced using modern tools of metabolic engineering and synthetic biology. These new microbial fuels have great potential to become viable alternatives and supplements for petroleum-derived liquid transportation fuels. MAN Latin America has worked in cooperation with REG Life Sciences, a North American industrial biotechnological company, to help in the development of high quality fuels for automotive purposes. The aim of this paper is to present the test engine results of a novel microbially produced fatty acid methyl ester (FAME), under the banner of UltraClean™ Diesel, in a Proconve P7 (Euro V) MAN D0834, diesel engine. Described are a comprehensive performance and emissions evaluation as well as an interpretation of the primary fuel properties. The test engine was operated with 100% standard Brazilian diesel (S50), blend of 20% of UltraClean™ Diesel with 80% of S50 and 100% UltraClean™ Diesel.
2014-10-13
Technical Paper
2014-01-2763
Somnuek Jaroonjitsathian, Peerawat Saisirirat, Komkrit Sivara, Manida Tongroon, Nuwong Chollacoop
Abstract Formerly, the Hydro-treated Vegetable Oil (HVO) blended fuels has been studied by running the New European Driving Cycle (NEDC) and found that the higher HVO blended fuel can suppress NOX, lowering the particulate matter (PM) while improving the vehicle fuel economy. The result also shown that the 20% HVO + 5%FAME blended with diesel fuel has been proven to compatible with the advance diesel engine technology via the severe engine durability tests and fuel injection system tests. Therefore, the effects of two paraffinic diesel fuels, which are Gas-to-Liquid (GTL) and Hydro-treated Vegetable Oil (HVO), on a common-rail DI diesel engine have been mainly focused in this work. The main objective of this work was to study the relationships between fuel properties and theirs combustion characteristics by analyzing cylinder pressure data and exhaust emissions intensively. Subsequently, the research team needs to quantify the effectiveness of using GTL and HVO as a blending component for superior diesel fuel.
2014-10-13
Technical Paper
2014-01-2762
Pradip Lingfa, Pranab Das, Lalit Das, Satya Naik
Abstract In the present experimental investigations the influence of injector opening pressures and injection timings on the engine performance and exhaust emissions of a naturally aspirated single cylinder diesel engine has been investigated. The test were conducted with four different fuels, namely diesel and Tung biodiesel blends (TB10, TB15, TB20 and TB50) at three different injector opening pressures (150 bar, 200 bar and 250 bar) respectively. Fuel injection opening pressures were varied by changing the spring tension of the needle valve of injector nozzle. The three different injection timings (Standard timing at 23° BTDC, Retarded Timing of 21° BTDC and Advanced Timing of 25° BTDC) were used. The injection timings were varied by changing the thickness of the shim. The entire tests were conducted at the constant engine speed of 1500 rpm under various load conditions. The experimental results showed that brake thermal efficiency (BTE) of Tung biodiesel improved at higher injector opening pressure.
2014-10-13
Technical Paper
2014-01-2730
Lei Zhu, Wugao zhang, Zhen Huang, Junhua Fang
Abstract Because of its cleanness and renewability, biodiesel has a great potential as the alternative of diesel fuel to confront with the increasing energy crisis and environment pollution. In this study, diesel oxidation catalyst (DOC) was used to reduce the typical regulated emission and particulate emission. The combined method of fuel design concept with diesel oxidation catalyst was applied in this study. DOC with Pt catalyst was equipped in the engine test bench in this study. The effects of DOC on diesel engine particulate emission fueled with Euro V diesel fuel, biodiesel and ethanol-biodiesel blends were investigated in this study. It was found that DOC seemed have no effects on NOx emission, while it could improve the oxidation reaction from NO to NO2. In the section of particulate emission, DOC could reduce the particulate mass and number concentration, especially in the range of smaller diameter particles. The SOF could be reduced effectively with DOC. With the increase of ethanol, the smaller particles (d<50nm) of ethanol-biodiesel blend fuels were more likely to be oxidized with diesel oxidation catalyst.
2014-10-13
Technical Paper
2014-01-2729
Paul Hellier, Nicos Ladommatos, Tom Headen, Stephen Bennington
Abstract Improvements in the efficiency of internal combustion engines and the development of renewable liquid fuels have both been deployed to reduce exhaust emissions of CO2. An additional approach is to scrub CO2 from the combustion gases, and one potential means by which this might be achieved is the reaction of combustions gases with sodium borohydride to form sodium carbonate. This paper presents experimental studies carried out on a modern direct injection diesel engine supplied with a solution of dissolved sodium borohydride so as to investigate the effects of sodium borohydride on combustion and emissions. Sodium borohydride was dissolved in the ether diglyme at concentrations of 0.1 and 2 % (wt/wt), and tested alongside pure diglyme and a reference fossil diesel. The sodium borohydride solutions and pure diglyme were supplied to the fuel injector under an inert atmosphere and tested at a constant injection timing and constant engine indicated mean effective pressure (IMEP). The 0.1 % sodium borohydride diglyme solution and pure diglyme exhibited durations of ignition delay shorter than that of the reference fossil diesel, while testing of the 2 % sodium borohydride solution resulted in failure of the fuel injector.
2014-10-13
Technical Paper
2014-01-2805
Benjamin Kingsbury, Jonathan Stewart, Zhentao Wu, Roy Douglas, Kang Li
Abstract This study describes an innovative monolith structure designed for applications in automotive catalysis using an advanced manufacturing approach developed at Imperial College London. The production process combines extrusion with phase inversion of a ceramic-polymer-solvent mixture in order to design highly ordered substrate micro-structures that offer improvements in performance, including reduced PGM loading, reduced catalyst ageing and reduced backpressure. This study compares the performance of the novel substrate for CO oxidation against commercially available 400 cpsi and 900 cpsi catalysts using gas concentrations and a flow rate equivalent to those experienced by a full catalyst brick when attached to a vehicle. Due to the novel micro-structure, no washcoat was required for the initial testing and 13 g/ft3 of Pd was deposited directly throughout the substrate structure in the absence of a washcoat. Initial results for CO oxidation indicate that the advanced micro-structure leads to enhanced conversion efficiency.
2014-10-13
Technical Paper
2014-01-2803
Aayush Mehrotra, Simhachalam Juttu, Siva Subramanian Ravishankar, Ghodke Pundlik Rambhaji, J G Suryawanshi
In this paper, Authors tried to investigate the influence of Low Temperature EGR (LtEGR) on NOx, PM emissions and fuel efficiency in NEDC 120 cycle. Sports Utility Vehicle (SUV) less than 3.5T vehicle selected for investigation of LtEGR. The existing water cooling circuit modified to suitable to handle the LtEGR concept without changing the existing EGR cooler. Cooled EGR technology has two benefits in terms of handling high EGR ratios and more fresh air within the engine displacement. Under this assumption separate LtEGR layout was prepared for the evolution of superior EGR cooling technologies and low pressure EGR. For the same volume of exhaust gas, higher mass of LtEGR is possible without change in fresh air mass as well LtEGR has advantage to occupy the less volume space for the same EGR mass fraction and thereby it is possible for higher fresh air; and engine to digest high amount of EGR or air depending upon the trade off and substantially improve the heat carrying capacity of exhaust gas.
2014-10-13
Technical Paper
2014-01-2770
Satoshi Kato, Yoshimitsu Kobashi, Yasumitsu Suzuki, Koji Tosa, Katsuyoshi Asaka, Alberto Macamo
Abstract Jatropha biofuel is promising renewal oil to produce biodiesel fuel through transesterification method which is shown in many papers. The ideal diesel alternative fuel obtained considering Jatropha as materials is Fatty Acid Methyl Ester (FAME). It is more desirable than the viewpoint of economical efficiency and CO2 control to operate a diesel engine with Jatropha crude (JC) oil. It is the purpose of this research to examine a possibility of using advantageous JC oil direct use as diesel engine fuel, in consideration of the sustainable production of the Jatropha biofuel in Mozambique. The adaptability to the diesel engine of diesel oil and the mixed fuel of JC was examined. Jatropha crude oil contains phorbol ester (PEs) which is a promoter of cancer. Measurement of the concentration of PEs in an exhaust gas was performed using High Performance Liquid Chromatography (HPLC). Skip cycle operation was performed for diesel engine with an electronically-controlled fuel injection system, and it was checked that the PEs concentration in the exhaust gas in low load operation which imitated cold starting condition.
2014-10-13
Technical Paper
2014-01-2782
Junya Iwasaki, Yasunori Shimizu, Hiroshi Fujita, Moritsugu Kasai
Abstract Automobile exhaust gas contains various harmful substances other than carbon dioxide, so exhaust gas post-processing devices have been developed to reduce their environmental load. Engine oil has contributed to the improvement of automobiles' environmental performance due to its excellent fuel-saving and long-drain properties. Recently, the lifetime of an exhaust gas post-processing device has been reported to decrease due to ash and phosphorus in engine oil. We have developed non-phosphorus and non-ash engine oil (NPNA), in which metal-based detergents and zinc dialkyldithiophosphate (ZnDTP) were not contained. We have performed a verification test for NPNA using an actual engine. In a performance test for a diesel particulate filter (DPF), the amount of soot and ash deposited onto a DPF was smaller when NPNA was used than when commercially available engine oil was used. In a performance test for catalysts, the exhaust gas purifying ratio was higher when NPNA was used than when commercially available engine oil was used.
2014-10-13
Technical Paper
2014-01-2823
Norifumi Mizushima, Daisuke Kawano, Hajime Ishii, Yutaka Takada, Susumu Sato
Abstract Widespread use of biofuels for automobiles would greatly reduce CO2 emissions and increase resource recycling, contributing to global environmental conservation. In fact, activities for expanding the production and utilization of biofuels are already proceeding throughout the world. For diesel vehicles, generally, fatty acid methyl ester (FAME) made from vegetable oils is used as a biodiesel. In recent years, hydrotreated vegetable oil (HVO) has also become increasingly popular. In addition, biomass to liquid (BTL) fuel, which can be made from any kinds of biomass by gasification and Fischer-Tropsch process, is expected to be commercialized in the future. On the other hand, emission regulations in each country have been tightened year by year. In accordance with this, diesel engines have complied with the regulations with advanced technologies such as common-rail fuel injection system, high pressure turbocharger, EGR and aftertreatment system. Unfortunately, the engine control system with these advanced technologies is adapted to conventional diesel fuels.
2014-10-13
Technical Paper
2014-01-2818
Mohammad Reza Hamedi, Athanasios Tsolakis, Jose Martin Herreros
Abstract Recent developments in diesel engines lead to increased fuel efficiency and reduced exhaust gas temperature. Therefore more energy efficient aftertreatment systems are required to comply with tight emission regulations. In this study, a computational fluid dynamics package was used to investigate the thermal behaviour of a diesel aftertreatment system. A parametric study was carried out to identify the most influential pipework material and insulation characteristics in terms of thermal performance. In the case of the aftertreatment pipework and canning material effect, an array of different potential materials was selected and their effects on the emission conversion efficiency of a Diesel Oxidation Catalyst (DOC) were numerically investigated over a driving cycle. Results indicate that although the pipework material's volumetric heat capacity was decreased by a factor of four, the total emission reduction was only considerable during the cold start. Different insulation strategies (e.g. double layer pipe with air gap and vacuum) were simulated using CFD and the improvement in the DOC emission conversion was monitored over the New European Driving Cycle (NEDC).
2014-10-13
Technical Paper
2014-01-2821
Jonathan Stewart, Roy Douglas, Alexandre Goguet, Cristina Elena Stere, Luke Blades
Abstract One of the most critical aspects in the development of a kinetic model for automotive applications is the method used to control the switch between limiting factors over the period of the chemical reaction, namely mass transfer and reaction kinetics. This balance becomes increasingly more critical with the automotive application with the gas composition and gas flow varying throughout the automotive cycles resulting in a large number of competing reactions, with a constantly changing space velocity. A methodology is presented that successfully switches the limitation between mass transfer and reaction kinetics. This method originally developed for the global kinetics model using the Langmuir Hinshelwood approach for kinetics is presented. The methodology presented is further expanded to the much more complex micro-kinetics approach taking into account various kinetic steps such as adsorption/desorption and surface reactions. The dual kinetic model is then tested against experimental data from two lab reactors one using spatially resolved data and one using the conventional end pipe analysis.
2014-10-13
Technical Paper
2014-01-2820
Rong Ma, Chao He, Jiaqiang Li
A simulation model of catalyzed diesel particulate filter (CDPF) is established based on the CFD software FIRE and has been validated through a series of experimental comparison. This model simulates the CDPF continuous regeneration process, and the factors that influence the exhaust NO2 concentration from CDPF including oxygen concentration, exhaust temperature, space velocity, proportion of NO2/NOX and soot mass fraction are studied. The results show that the higher oxygen concentration causes an increase in NO2/NOX. The NO2/NOX is significantly increased when the exhaust temperature is about 350 °C based on the simulation conditions when the inlet oxygen concentration is at 5.79% and the space velocity is 7s−1. The space velocity in a certain degree leads to higher NO2/NOX. For the soot mass, there is no significant influence of increasing proportion of the NO2/NOX.
2014-10-13
Technical Paper
2014-01-2809
Kohei Yoshida, Yusuke Nozaki, Toshihiro Mori, Yuki Bisaiji, Yuki Haba, Kazuhiro Umemoto, Takao Fukuma
Abstract In this paper, a control strategy to switch NSR (NOx storage and reduction) function from standard DeNOx by rich combustion to DiAir (Diesel NOx After-treatment by Adsorbed Intermediate Reductants) and additional advantages to use HCI (Hydrocarbon Injector) during desulfation were introduced. Investigations under a transient cycle suggest that NOx conversion with DiAir is strongly affected by preliminary NOx storage condition in the NSR catalyst. To avoid NOx breakthrough just after starting HC dosing for DiAir, a rich operation to reduce stored NOx was shown to be important and high NOx conversion could be maintained using this control strategy under a transient cycle. Furthermore, by combining HCI and in-cylinder post injection, usage of rich condition for NSR DeSOx can be expand to wider engine speed and load area. Thanks to a high NOx conversion efficiency in high temperature, including DPF(diesel particulate filter) regeneration, with DiAir, a NOx storage function in low load driving and the advantage of HCI during DeSOx, promising potential to reduce NOx emission in real driving condition was shown.
2014-10-13
Technical Paper
2014-01-2808
Tao Tang, Jun Zhang, Shi-jin Shuai, Dongxiao Cao
Abstract Selective catalytic reduction (SCR) has been demonstrated as one of the most promising technologies to reduce NOx emissions from heavy-duty diesel engines. To meet the Euro VI regulations, the SCR system should achieve high NOx reduction efficiency even at low temperature. In the SCR system, NH3 is usually supplied by the injection of urea water solution (UWS), therefore it is important to improve the evaporation and decomposition efficiency of UWS at low temperature and minimize urea deposits. In this study, the UWS spray, urea decomposition, and the UWS impingement on pipe wall at low temperature were investigated based on an engine test bench and computational fluid dynamics (CFD) code. The decomposition of urea and deposits was analyzed using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR). The TGA experiment shows that urea decomposition started at about 150°C, and exhibited two stages of rapid mass loss.
2014-10-13
Technical Paper
2014-01-2814
Andrew Pedlow, Geoffrey McCullough, Alexandre Goguet, Ken Hansen
Abstract Mathematical modelling has become an essential tool in the design of modern catalytic systems. Emissions legislation is becoming increasingly stringent, and so mathematical models of aftertreatment systems must become more accurate in order to provide confidence that a catalyst will convert pollutants over the required range of conditions. Automotive catalytic converter models contain several sub-models that represent processes such as mass and heat transfer, and the rates at which the reactions proceed on the surface of the precious metal. Of these sub-models, the prediction of the surface reaction rates is by far the most challenging due to the complexity of the reaction system and the large number of gas species involved. The reaction rate sub-model uses global reaction kinetics to describe the surface reaction rate of the gas species and is based on the Langmuir Hinshelwood equation further developed by Voltz et al. [1] The reactions can be modelled using the pre-exponential and activation energies of the Arrhenius equations and the inhibition terms.
Viewing 31 to 60 of 22470

Filter

  • Article
    1065
  • Book
    75
  • Collection
    38
  • Magazine
    499
  • Technical Paper
    20183
  • Standard
    610