Browse Topic: Dimethyl ether (DME)

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Optimization of the Numerical Spray Modeling for Polyoxymethylene Dimethyl Ethers for Combustion Prediction in CONVERGE2025-01-502604/03/2025
Different approaches are undertaken to mitigate the impact of the transport sector on climate change. Alongside electrifying powertrains, sustainable e-fuels such as polyoxymethylene dimethyl ethers (OME) are considered a promising bridging technology for different applications. However, this requires that the engines are optimized for the new fuels. Accordingly, this study aims to optimize the numerical spray modeling of OME in CONVERGE. Based on the KH–RT break-up model, the spray simulations of three different commercial injectors for heavy-duty applications are analyzed regarding the predictability of the liquid and gaseous penetration lengths and the total simulation time. A sensitivity analysis is conducted for the turbulence model, mesh size, and spray parameters prior to optimizing the spray model and validating it with experimental results. While each parameter individually influences the different phases of the injection event, the sensitivity analysis reveals that the break
Zepf, Andreas, Härtl, Martin, Jaensch, Malte
Combustion Characterization of DME-Fueled Dual Fuel Combustion with Premixed Ethanol 2022-01-056203/29/2022
The heterogeneous nature of direct injection (DI) combustion yields high combustion efficiencies but harmful emissions through the formation of high nitrogen oxide (NOx) and/or smoke emissions. In response, extensive empirical and computational research has focused on balancing the NOx-smoke trade-off to limit diesel DI combustion emissions. The use of dimethyl ether (DME) fuel in DI compression ignition engines is capable of releasing near-smoke-free emissions. Moreover, the addition of a premixed fuel can minimize DI fuel energy requirements and limit extended injection durations and thus improve overall homogeneity. For this technique, a low reactivity fuel such as Ethanol is essential to avoid the early onset of autoignition. In this work, empirical experiments of dual fuel operation have been conducted using premixed ethanol with direct injected DME. The engine performance was characterized with DI diesel fuel as a baseline, and the matching operation of DME was compared
Leblanc, Simon, Yu, Xiao, Sandhu, Navjot S., Zheng, Ming
A Study of Combustion Inefficiencies in SI Engines Powered by Alcohol and Ether Fuels Using Detailed Emission Speciation2022-01-061703/29/2022
Advanced combustion engines, as power sources, dominate all aspects of the transportation sector. Stringent emission and fuel efficiency standards have promoted the research interest in advanced combustion strategies and alternative fuels. Owing to the comparable energy density to the existing fossil fuels and renewable production, alcohol and ether fuels may be a suitable replacement, or an additive to the gasoline/diesel fuels to meet the future emission standards with minimal modification to current engine geometry. Furthermore, lean and diluted combustion are well-researched pathways for efficiency improvement and reduction of engine-out emissions of modern engines. However, lean-burn or EGR dilution can introduce combustion inefficiencies in the form of excessive hydrocarbon, carbon monoxide, and hydrogen emissions. In this study, the total energy loss to the exhaust in the form of emission species due to incomplete/inefficient combustion of alcohol (butanol and ethanol) and ether
Sandhu, Navjot Singh, Yu, Xiao, Leblanc, Simon
Laminar flame speed measurements of propane/DME/air mixtures2022-01-062403/29/2022
An experimental study on the laminar flame speeds (LFS) of premixed propane/dimethyl-ether (DME)/air flames was conducted inside a constant-volume chamber at UCF. Mixtures of propane and DME were selected for this study as they show promise as a fuel source that can be utilized in the automotive diesel industry as a low emission alternative fuel. The LFS of a fuel mixture is a key characteristic of combustion for its application in the design process of engines, as it can be used as a metric for fuel performance. Further underscoring the importance of gathering LFS data for these mixtures is its use in validating chemical kinetic mechanisms that can be utilized for further research in the field. LFS is dependent on fuel/oxidant mixture temperature, pressure, and equivalence ratio. While some studies exist examining other characteristics of combustion with regards to propane/DME fuel mixtures, there is minimal information pertaining to the laminar flame speed of the mixtures. This study
Weiner, Joshua, kim, Gihun, Ghorpade, Ritesh
E-Fuel applications in Non Road Mobile Machinery2022-32-007401/09/2022
Professional users in particular will continue to rely on internal combustion engine drives in the future due to high power requirements and high daily energy consumption. Especially if they have to work in rural areas without the possibility of recharging batteries, such as in forestry or maintenance of road verges or railway lines. For these applications, it must be possible to run sustainable fuels for defossilization and drastically reduced CO2 emissions. This paper provides insights into a possible future fuel market and describes its evolution towards a more sustainable future from the perspective of a handheld equipment manufacturer. As developments in the fuel market are currently difficult to predict, manufacturers of hand-held power tools with combustion engines need to be prepared for changes in the composition of fuels that might become available on the market. This paper presents the engine performance results of both a 2-stroke engine and a 4-stroke engine, each with
von Gaertringen, Christoph Hiller, Schwerin, René, Schweiger, Stefan, Kölmel, Armin, Lochmann, Holger, Schmidt, Stephan, Zinner, Christian, Kirchberger, Roland, Gschanes, Dominik
Chemical Reactivity Control of DME/Ethanol Dual Fuel Combustion2021-01-117609/21/2021
The use of renewable fuels in place of conventional hydrocarbon fuels can minimize the carbon footprint of internal combustion engines. DME has been treated as a suitable surrogate to diesel fuel because of its high reactivity and soot-less combustion characteristics. The lower energy density of DME fuel demands a higher fuel supply rate to match the engine loads compared to diesel, which was achieved through prolonged injection duration and larger nozzle holes. When used as a pilot fuel to control the combustion behavior in a dual-fuel application, the fuel energy delivery rate becomes less critical allowing the use of a standard diesel common-rail injector for DME direct injection. In this work, the combustion of DME-Ethanol dual-fuel reactivity-controlled compression ignition was experimentally investigated. Compare with diesel, the high volatility of neat DME fuel can enhance its mixing with port injected fuel even under very early fuel injection timing, which is critical for
Leblanc, Simon, Sandhu, Navjot Singh, Yu, Xiao, Zheng, Ming, Tjong, Jimi
Fuel Dosing on a Diesel Oxidation Catalyst for After-Treatment System Heating on a Heavy-Duty Engine Powered by Polyoxymethylene Dimethyl Ethers2020-01-215709/15/2020
Polyoxymethylene dimethyl ethers (OME) are synthetic fuels, which offer the property of sustainability because the reactants of production base on hydrogen and carbon dioxide on the one hand, and the air pollution control in consequence of a soot-free combustion in a diesel engine on the other hand. High exhaust gas recirculation (EGR) rates are a promising measure for nitrogen oxide (NOx) reduction without increasing particle emissions because of the resolved soot-NOx trade-off. However, EGR rates towards stoichiometric combustion in OME operation reveals other trade-offs such as methane and formaldehyde emissions. To avoid these, a lean mixture with a combination of EGR and exhaust after-treatment with selective catalytic reduction (SCR) is useful. The limitation of urea dosing due to the light-off temperature of SCR systems requires heating measures. Besides electrical heating, fuel injection into the diesel oxidation catalyst (DOC) for an exothermic reaction is an effective method
Gelner, Alexander D., Pastoetter, Christian, Beck, Harald A., Härtl, Martin, Wachtmeister, Georg
Exhaust Emissions from a City Bus Fuelled by Oxygenated Diesel Fuel2020-01-209509/15/2020
The benefits associated with the use of oxygen-containing diesel fuels in passenger cars are quite well described in the literature. This work describes the results of an 18-meter EEV city bus fueled with diesel fuel with the addition of 10% v/v of triethylene glycol dimethyl ether. This compound was chosen because it was effective in reducing exhaust emissions from light duty diesel vehicles. Emission tests (CO, HC, NOx and PM) of the city bus were performed over SORT (Standardized On-Road Tests) cycles using portable exhaust gas analyzers - PEMS. Significant differences in the emission of exhaust components were observed in individual SORT cycles. The level of road emissions reduced as the traffic smoothness increased, i.e. from the SORT 1 to SORT 3 cycle. The largest reduction in bus emissions associated with the use of the oxygenated additive (triethylene glycol dimethyl ether) applies to carbon monoxide and ranges from 50% for the SORT 3 cycle up to 90% for the SORT 1. For the
Kozak, Miloslaw, Lijewski, Piotr, Fuc, Pawel
A Study of a Lean Homogeneous Combustion Engine System with a Fuel Reformer Cylinder2019-01-217712/19/2019
The Dual-Fuel (DF) combustion is a promising technology for efficient, low NOx and low exhaust particulate matter (PM) engine operation. To achieve equivalent performance to a DF engine with only the use of conventional liquid fuel, this study proposes the implementation of an on-board fuel reformation process by piston compression. For concept verification, DF combustion tests with representative reformed gas components were conducted. Based on the results, the controllability of the reformed gas composition by variations in the operating conditions of the reformer cylinder were discussed.
Asai, Go, Tokuoka, Yuki, Bayer, Thomas, Ishiguro, Shuntaro, Shibata, Gen, Ogawa, Hideyuki, Kobashi, Yoshimitsu, Watanabe, Yusuke
Development of an iso-Octane Skeletal Combustion Mechanism based on Primary Sensitive Reactions2019-01-235012/19/2019
In this study, an iso-octane skeletal combustion mechanism was constructed based on the sensitivity and reaction path analysis of the most recent published detailed iso-octane combustion mechanism. The major reactions relevant to the fuel consumption were determined based on sensitivity analysis at 650, 750 and 850 K under pressure of 20 bar for stoichiometric iso-octane/air mixture. Additional reactions were added to balance the reaction species. In particular, two lumped octyl radicals were used to describe the H atom abstraction products of iso-octane due to their distinctly opposite sensitivities on the fuel reactivity. In addition, major reaction equations for the description of fuel molecule consumption were kept as the same as those in the detailed mechanism for the purpose of traceability. The reaction rate constants of most reactions were taken from the detailed mechanism, and were kept unchanged except for a few reactions, of which the reaction rate constants were slightly
MENG, Xiangzan, MENG, Yi
Etching of Fluoropolymer InsulationsARP6167 (Current)06/11/2019
This SAE Aerospace Recommended Practice (ARP) describes the etching of fluoropolymer electrical wire insulations to ensure that all facets of the process from the chemistry to the processing, to the storage and handling are well defined.
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
A Computational Study on Laminar Flame Propagation in Mixtures with Non-Zero Reaction Progress2019-01-094604/02/2019
Flame speed data reported in most literature are acquired in conventional apparatus such as the spherical combustion bomb and counterflow burner, and are limited to atmospheric pressure and ambient or slightly elevated unburnt temperatures. As such, these data bear little relevance to internal combustion engines and gas turbines, which operate under typical pressures of 10-50 bar and unburnt temperature up to 900K or higher. These elevated temperatures and pressures not only modify dominant flame chemistry, but more importantly, they inevitably facilitate pre-ignition reactions and hence can change the upstream thermodynamic and chemical conditions of a regular hot flame leading to modified flame properties. This study focuses on how auto-ignition chemistry affects flame propagation, especially in the negative-temperature coefficient (NTC) regime, where dimethyl ether (DME), n-heptane and iso-octane are chosen for study as typical fuels exhibiting low temperature chemistry (LTC). The
Lin, Han, Zhao, Peng, Ge, Haiwen
An Optical Study on the Combustion of Gasoline/PODEn Blends in a Constant Volume Vessel2018-01-174809/10/2018
Polyoxymethylene dimethyl ethers (PODEn) have high cetane number, high oxygen content and high volatility, therefore can be added to gasoline to optimize the performance and soot emission of Gasoline Compression Ignition (GCI) combustion. High speed imaging was used to investigate the spray and combustion process of gasoline/PODEn blends (PODEn volume fraction 0%-30%) under various ambient conditions and injection strategies in a constant volume vessel. Results showed that with an increase of PODEn proportion from 10% to 30%, liquid-phase penetration of the spray increased slightly, ignition delay decreased from 3.8 ms to 2.0 ms and flame lift off length decreased 29.4%, causing a significant increase of the flame luminance. For blends with 20% PODEn, when ambient temperature decreased from 893 K to 823 K, the ignition delay increased 1.3 ms and the flame luminance got lower. When increasing the injection pressure, the liquid phase length and the ignition delay got a little longer and
Ma, Yue, Cui, Longxi, Ma, Xiao, Wang, Zhi, Shuai, Shi-Jin
A Computational Study of Lean Limit Extension of Alcohol HCCI Engines2018-01-167909/10/2018
The purpose of present numerical study was to extend the operating range of alcohol (methanol and ethanol) fueled Homogeneous Charge Compression Ignition (HCCI) engine under low load conditions. Ignition of pure methanol and ethanol under HCCI mode of operation requires high intake temperatures and misfires at low loads are common in HCCI engines. Three methods have been adapted to optimize the use of methanol and ethanol for HCCI operation without increasing the intake temperature. First, blending methanol and ethanol with ignition improver, namely di-methyl ether (DME) and di-ethyl ether (DEE), was used to increase the cetane number and ignitability of premixed charge. Second, based on the blended fuels, the spark assistance was used to reduce required intake temperature for auto-ignition. Third, DME and DEE were directly injected to methanol and ethanol operated HCCI engine, in the form of Reactivity Controlled Compression Ignition (RCCI) combustion. Negligible improvement in
Zhou, Qiyan, Mubarak Ali, Mohammed Jaasim, Mohan, Balaji, Lu, Xing-Cai, Im, Hong
Intermediate Combustion Modes between Conventional Diesel and RCCI2018-01-024904/03/2018
In recent years, several unconventional fueling modes have been developed for dual-fuel compression ignition (CI) engines. One such mode is reactivity controlled compression ignition (RCCI), which utilizes both a low-reactivity fuel (LRF) and a high-reactivity fuel (HRF) via separate injection systems. RCCI has been tested with many fuels, but there have been relatively few tests on the intermediate modes that exist in between RCCI and conventional diesel combustion (CDC). For this purpose, a quantitative classification system of fueling modes was created and used to test incremental changes in the fueling mode of a 1.9L General Motors (GM) turbodiesel engine, shifting between CDC and RCCI at a single speed/load point. This engine used a 5:2 mass ratio blend of propane and dimethyl ether (DME) as its LRF and ultra-low-sulfur diesel (ULSD) as its HRF. The results confirm previous findings that RCCI can achieve improvements in thermal efficiency, nitrogen oxide (NOx) emissions, and soot
Martin, Jonathan, Boehman, Andre, Topkar, Rutvik, Chopra, Sumit, Subramaniam, Uday, Chen, Heng
The Direct Transition of Fuel Sprays to theDense-Fluid Mixing Regime in the Contextof Modern Compression Ignition Engines2018-01-029804/03/2018
Fuel supercriticality has recently received significant attention due to the elevated pressures and temperatures that directly-injected (DI) fuel sprays encounter in modern internal combustion (IC) engines. This paper presents a theoretical examination of conventional and alternative DI fuels at conditions relevant to the operation of compression ignition (CI) engines. The focus is to identify the conditions under which the injected liquid fuel can bypass the atomization process and directly transition to a diffusional mixing regime with the chamber gas. Evaluating the microscopic length-scales of the phase boundary associated with the injection of liquid nitrogen into its own vapor, it is found that the conventional threshold based on the interfacial Knudsen number (i.e. Kn = 0.1) does not adequately quantify the direct transition between sub- and supercriticality. Instead, a threshold that is an order of magnitude smaller is more appropriate for this purpose. Extending the analysis
Poursadegh, Farzad, Lacey, Joshua, Brear, Michael, Gordon, Robert
Experimental Investigation of Combustion and Emission Characteristics of the Direct Injection Dimethyl Ether Enabled Micro-Flame Ignited (MFI) Hybrid Combustion in a 4-Stroke Gasoline Engine2018-01-124704/03/2018
Controlled Auto-Ignition (CAI), also known as Homogeneous Charge Compression Ignition (HCCI), has the potential to improve gasoline engines’ efficiency and simultaneously achieve ultra-low NOx emissions. Two of the primary obstacles for applying CAI combustion are the control of combustion phasing and the maximum heat release rate. To solve these problems, dimethyl ether (DME) was directly injected into the cylinder to generate multi-point micro-flame through compression in order to manage the entire heat release of gasoline in the cylinder through port fuel injection, which is known as micro-flame ignited (MFI) hybrid combustion. The combustion and emissions characteristics of MFI mode were investigated in a single-cylinder 4-stroke gasoline engine by the use of negative valve overlap (NVO) strategy at part loads when direct injection timing of DME was altered from -60 °CA to -40 °CA after top dead center, and the replacement ratio of DME for gasoline was no more than 20% at a fixed
Fu, Xue-Qing, He, Bang-Quan, Xu, Sipeng, Li, Hongtao, Chen, Tao, Zhao, Hua
Numerical Optimization of the Combustion System of a HD Compression Ignition Engine Fueled with DME Considering Current and Future Emission Standards2018-01-024704/03/2018
A genetic algorithm (GA) optimization methodology is applied to the design of the combustion system of a heavy-duty (HD) Diesel engine fueled with dimethyl ether (DME). The study has two objectives, the optimization of a conventional diffusion-controlled combustion system aiming to achieve US2010 targets and the optimization of a stoichiometric combustion system coupled with a three way catalyst (TWC) to further control NOx emissions and achieve US2030 emission standards. These optimizations include the key combustion system related hardware, bowl geometry and injection nozzle design as input factors, together with the most relevant air management and injection settings. The GA was linked to the KIVA CFD code and an automated grid generation tool to perform a single-objective optimization. The target of the optimizations is to improve net indicated efficiency (NIE) while keeping NOx emissions, peak pressure and pressure rise rate under their corresponding target levels. Compared to the
Benajes, Jesus, Novella, Ricardo, Hernández-López, Alberto, Kokjohn, Sage
Development of Surrogate Model for Oxygenated Wide-Distillation Fuel with Polyoxymethylene Dimethyl Ether2017-01-233610/08/2017
Polyoxymethylene Dimethyl Ether (PODEn) is a promising green additive to diesel fuel, owing to the unique chemical structure (CH3O[CH2O]nCH3, n≥2) and high cetane number. Together with the general wide-distillation fuel (WDF), which has an attractive potential to reduce the cost of production of vehicle fuel, the oxygenated WDF with PODEn can help achieve a high efficiency and low emissions of soot, NOx, HC, and CO simultaneously. In this paper, the first detailed reaction mechanism (225 species, 1082 reactions) which can describe the ignition characteristics of PODE1 and PODE3 at low temperature was developed. To validate this mechanism, rapid compression machine (RCM) was used to conduct the quasi-homogeneous experiments to measure the ignition delay time at various effective temperatures (600 K - 1000 K) for four different PODE1/O2/N2/Ar mixture (ϕ=0.25, O2:Ar=1:5; ϕ=0.5, O2:Ar:N2 = 1:2.5:2.5; ϕ=1.0, O2:Ar:N2 = 1:2.5:2.5; ϕ=1.0, O2:Ar:N2 = 1:5:5) and two different effective
He, Tanjin, Liu, Hao-ye, Wang, Yingdi, Wang, Boyuan, Liu, Hui, Wang, Zhi
Development of a Reduced Chemical Mechanism for Dimethyl Ether (DME) Using a Decoupling Methodology2017-01-219110/08/2017
Dimethyl ether (DME) attracts increasing attentions in recent years, because it can reduce the carbon monoxide (CO), unburned hydrocarbon (HC), and soot emissions for engines as the transportation fuel or the fuel additive. In this paper, a reduced DME oxidation mechanism is developed using the decoupling methodology. The rate constants of the fuel-related reactions are optimized using the non-dominated sorting genetic algorithm II (NSGA-II) to reproduce the ignition delay times in shock tubes and major species concentrations in jet-stirred reactors (JSR) over low-to-high temperatures. In NSGA-II, the range of the rate constants was considered to ensure the reliability of the optimized mechanism. Moreover, an improved objective function was proposed to maintain the faithfulness of the optimized mechanism to the original reaction mechanism, and a new method was presented to determine the optimal solution from the Pareto front. The final reduced mechanism includes 42 species and 171
Chang, Yachao, Jia, Ming, Zhang, Yanzhi, Li, Yaopeng, Fan, Weiwei, Xie, MaoZhao
PLII-LEM and OH* Chemiluminescence Study on Soot Formation in Spray Combustion of PODEn-Diesel Blend Fuels in a Constant Volume Vessel2017-01-232910/08/2017
Polyoxymethylene dimethyl ethers (PODEn) are promising alternative fuel candidates for diesel engines because they present advantages in soot reduction. This study uses a PODEn mixture (contains PODE3-6) from mass production to provide oxygen component in blend fuels. The spray combustion of PODEn-diesel bend fuels in a constant volume vessel was studied using high speed imaging, PLII-LEM and OH* chemiluminescence. Fuels of several blend ratios are compared with pure diesel. Flame luminance data show a near linear decrease tendency with the blend ratio increasing. The OH* images reveal that the ignition positions of all the cases have small differences, which indicates that using a low PODEn blend ratio of no more than 30% does not need significant adjustment in engine combustion control strategies. It is found that 30% PODEn blended with diesel (P30) can effectively reduce the total soot by approximately 68% in comparison with pure diesel. The profile of the soot distribution of the
Ma, Xiao, Ma, Yue, Sun, Shuaishuai, Shuai, Shi-Jin, Wang, Zhi, Wang, Jian-Xin
Experimental Study on High-Load Extension of Gasoline/PODE Dual-Fuel RCCI Operation Using Late Intake Valve Closing2017-01-075403/28/2017
The dual-fuel Reactivity Controlled Compression Ignition (RCCI) combustion could achieve high efficiency and low emissions over a wide range of operating conditions. However, further high load extension is limited by the excessive pressure rise rate and soot emission. Polyoxymethylene dimethyl ethers (PODE), a novel diesel alternative fuel, has the capability to achieve stoichiometric smoke-free RCCI combustion due to its high oxygen content and unique molecule structure. In this study, experimental investigations on high load extension of gasoline/PODE RCCI operation were conducted using late intake valve closing (LIVC) strategy and intake boosting in a single-cylinder, heavy-duty diesel engine. The experimental results show that the upper load can be effectively extended through boosting and LIVC with gasoline/PODE stoichiometric operation. With the retarding of LIVC timing and increase of cyclic fuel quantity, higher boosting pressure and lower Exhaust Gas Recirculation (EGR) ratio
Wang, Hu, Tong, Laihui, Zheng, Zunqing, Yao, Mingfa
Reforming Controlled Homogenous Charge Compression Ignition -Simulation Results2016-32-001411/08/2016
A computer model was built and a theoretical analysis was performed to predict the behavior of a system containing Homogenous charge compression ignition (HCCI) engine and a methanol reformer. The reformer utilizes the waste heat of the exhaust gases to sustain the two subsequent processes: dehydration of methanol to dimethyl ether (DME) and water, and methanol steam reforming (SRM) where methanol and water react to mainly hydrogen, CO and CO2. Eventually, a gaseous mixture of DME, H2, CO, CO2, water (reused) and some other species is created in these processes. This mixture is used for the engine feeding. By adding water to the methanol and fixing the vaporized fuel's temperature, it is possible to manage the kinetics of chemical processes, and thus to control the products’ composition. This allows controlling the HCCI combustion. By a magnification of H2/DME ratio the ignition delay is increased and so it is possible to synchronize the ignition timing and also to control combustion
Eyal, Amnon, Tartakovsky, Leonid
Influence of Supercharging and EGR on Multi-stage Heat Release in an HCCI Engine2016-32-000911/08/2016
Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest as a combustion system that offers the advantages of high efficiency and low exhaust emissions. However, it is difficult to control the ignition timing in an HCCI combustion system owing to the lack of a physical means of initiating ignition like the spark plug in a gasoline engine or fuel injection in a diesel engine. Moreover, because the mixture ignites simultaneously at multiple locations in the cylinder, it produces an enormous amount of heat in a short period of time, which causes greater engine noise, abnormal combustion and other problems in the high load region. The purpose of this study was to expand the region of stable HCCI engine operation by finding a solution to these issues of HCCI combustion. The results of previous studies have shown that the application of supercharging when using a fuel blend of dimethyl ether and methane moderates the rapid rate of combustion, resulting in
Takamura, Yuki, Shima, Takahiro, Suzuki, Hirotaka, Agui, Keito, Iijima, Akira, Shoji, Hideo
A Study of HCCI Operating Range Expansion by Applying Reaction Characteristics of Low-Carbon Alternative Fuels2016-32-001111/08/2016
Issues that must be addressed to make Homogeneous Charge Compression Ignition (HCCI) engines a practical reality include the difficulty of controlling the ignition timing and suppression of rapid combustion under high load conditions. Overcoming these issues to make HCCI engines viable for practical application is indispensable to the further advancement of internal combustion engines. Previous studies have reported that the operating region of HCCI combustion can be expanded by using DME and Methane blended fuels.(1), (2), (3), (4), (5) The reason is that the reaction characteristics of these two low-carbon fuels, which have different ignition properties, have the effect of inducing heat release in two stages during main combustion, thus avoiding excessively rapid combustion. However, further moderation of rapid combustion in high-load region is needed to expand the operation region. This study focused on supercharging and use of blended fuels. For the purpose of promoting the
Agui, Keito, Suzuki, Hirotaka, Takamura, Yuki, Iijima, Akira, Shoji, Hideo
Well-to-Wheels Emissions of Greenhouse Gases and Air Pollutants of Dimethyl Ether from Natural Gas and Renewable Feedstocks in Comparison with Petroleum Gasoline and Diesel in the United States and Europe2016-01-220910/17/2016
Dimethyl ether (DME) is an alternative to diesel fuel for use in compression-ignition engines with modified fuel systems and offers potential advantages of efficiency improvements and emission reductions. DME can be produced from natural gas (NG) or from renewable feedstocks such as landfill gas (LFG) or renewable natural gas from manure waste streams (MANR) or any other biomass. This study investigates the well-to-wheels (WTW) energy use and emissions of five DME production pathways as compared with those of petroleum gasoline and diesel using the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model developed at Argonne National Laboratory (ANL). The five DME pathways include 1) fossil NG with large-scale DME plants, 2) methanol from fossil NG with large-scale plants for both methanol and DME (separately), 3) LFG with small-scale DME plants, 4) manure-based biogas with small-scale DME plants, and 5) methanol from black liquor gasification with small
Lee, Uisung, Han, Jeongwoo, Wang, Michael, Ward, Jacob, Hicks, Elliot, Goodwin, Dan, Boudreaux, Rebecca, Hanarp, Per, Salsing, Henrik, Desai, Parthav, Varenne, Emmanuel, Klintbom, Patrik, Willems, Werner, Winkler, Sandra L., Maas, Heiko, De Kleine, Robert, Hansen, John, Shim, Tine, Furusjö, Erik
Evaluation of Hydrous Ethanol Fuel Lubricity by HFRR2016-01-226010/17/2016
Improvement of thermal efficiency is an important problem for internal combustion engines. Fuel reforming with dehydrogenation reaction by exhaust heat is one of the measures to increase thermal efficiency using hydrogen mixed SI combustion. For this kind engine system, hydrous ethanol has a good potential. Furthermore, when the hydrous ethanol inject to combustion chamber directory, high compression combustion can be achieved by its large amount of latent heat. Therefore, fuel lubricity is an important check point for the hydrous ethanol reforming engine systems. In this study, effect of water concentrations within ethanol on the hydrous ethanol fuel lubricity has been evaluated using HFRR (High-Frequency Reciprocating Rig) test method. Wear scar diameter on 100 % of ethanol was around 700 μm which was a little better than gasoline lubricity. When the water concentration within ethanol was increased, the wear scar diameters were decreasing around 330 μm. Considering this phenomenon by
Oguma, Mitsuharu, Matsuno, Mayumi, Kaitsuka, Masayoshi, Higurashi, Kazuaki
Measurement of Sound Speed in DME in a Wide Range of Pressure and Temperature Including the Critical Point2016-01-225810/17/2016
Dimethyl ether (DME) is a promising alternative fuel for compression ignition (CI) engines. DME features good auto ignition characteristics and soot-free combustion. In order to develop an injection system suitable for DME, it is necessary to understand its fuel properties. Sound speed is an important fuel property that affects the injection characteristics. However, the measurement data under high-pressures corresponding to those in fuel injection systems are lacking. The critical temperature of DME is lower than that of diesel fuel, and is close to the injection condition. It is important to understand the behavior of the sound speed around the critical point, since the sound speed at critical point is extremely low. In this study, sound speed in DME in a wide pressure and temperature range of 1 MPa to 80 MPa, 298.15 K to 413.15 K, including the vicinity of the critical point, was measured. The sound speed in DME decreases as either the pressure falls or the temperature rises. It is
Okoshi, Yoshihiro, Kikuchi, Shinsuke, Mitsugi, Yuta, Tanaka, Kotaro, Kato, Masaaki, Tsuji, Tomoya, Konno, Mitsuru
Investigation of Fuel Effects on In-Cylinder Reforming Chemistry Using Gas Chromatography2016-01-075304/05/2016
Negative Valve Overlap (NVO) is a potential control strategy for enabling Low-Temperature Gasoline Combustion (LTGC) at low loads. While the thermal effects of NVO fueling on main combustion are well-understood, the chemical effects of NVO in-cylinder fuel reforming have not been extensively studied. The objective of this work is to examine the effects of fuel molecular structure on NVO fuel reforming using gas sampling and detailed speciation by gas chromatography. Engine gas samples were collected from a single-cylinder research engine at the end of the NVO period using a custom dump-valve apparatus. Six fuel components were studied at two injection timings: (1) iso-octane, (2) n-heptane, (3) ethanol, (4) 1-hexene, (5) cyclohexane, and (6) toluene. All fuel components were studied neat except for toluene - toluene was blended with 18.9% nheptane by liquid volume to increase the fuel reactivity. Additionally, a gasoline surrogate matching the broad molecular composition of RD587
Wolk, Benjamin, Ekoto, Isaac, Northrop, William
Compatibility of Dimethyl Ether (DME) and Diesel Blends with Fuel System Polymers: A Hansen Solubility Analysis Approach2016-01-083504/05/2016
The compatibility of notable infrastructure elastomers and plastics with DME and its blends with diesel fuel were examined using solubility analysis. The elastomer materials were fluorocarbon, acrylonitrile butadiene rubber (NBR), styrene butadiene (SBR), neoprene, polyurethane and silicone. Plastic materials included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyoxymethylene (POM), polybutylene terephthalate (PBT), polypropylene (PP), high density polyethylene (HDPE), along with several nylon grades and thermosetting resins. These materials have been rigorously studied with other fuel types, and their volume change results were found to correspond well with their predicted solubility levels. A Hansen solubility analysis was performed for each material with DME, diesel, and blends of both fuel components. The results for the elastomers indicate that DME and its blends with diesel fuel will offer
Kass, Michael D., Daw, Charles
Characteristics of Formaldehyde (CH 2 O) Formation in Dimethyl Ether (DME) Spray Combustion Using PLIF Imaging2016-01-086404/05/2016
Recognition of Dimethyl Ether (DME) as an alternative fuel has been growing recently due to its fast evaporation and ignition in application of compression-ignition engine. Most importantly, combustion of DME produces almost no particulate matter (PM). The current study provides a further understanding of the combustion process in DME reacting spray via experiment done in a constant volume combustion chamber. Formaldehyde (CH2O), an important intermediate species in hydrocarbon combustion, has received much attention in research due to its unique contribution in chemical pathway that leads to the combustion and emission of fuels. Studies in other literature considered CH2O as a marker for UHC species since it is formed prior to diffusion flame. In this study, the formation of CH2O was highlighted both temporally and spatially through planar laser induced fluorescence (PLIF) imaging at wavelength of 355-nm of an Nd:YAG laser at various time after start of injection (ASOI). The injection
Cung, Khanh, Zhu, Xiucheng, Moiz, Ahmed Abdul, Lee, Seong-Young, De Ojeda, William
Investigation of the Combustion Front Structure during Homogeneous Charge Compression Ignition Combustion via Laser Rayleigh Scattering Thermometry2016-01-074604/05/2016
The combustion propagation mechanism of homogeneous charge compression ignition combustion was investigated using planar laser Rayleigh scattering thermometry, and was compared to that of spark-ignition combustion. Ethylene and dimethyl ether were chosen as the fuels for SI and HCCI experiments and have nearly constant Rayleigh scattering cross-sections through the combustion process. Beam steering at the entrance window limited the load range for HCCI conditions and confined the quantitative interpretation of the results to local regions over which an effective beam steering correction could be applied. The SI conditions showed a clear bimodal temperature behavior with a well-defined interface between reactants and products. The HCCI results showed large regions that were partially combusted, i.e., at a temperature above the reactants but below the adiabatic flame temperature. Dual-imaging experiments confirm that the burned region was progressing towards the fully burned state. This
Blessinger, Matthew, Ghandhi, Jaal
HEUI Injector Modeling and ROI Experiments for High Injection Pressure of Diesel and Dimethyl Ether (DME)2016-01-085504/05/2016
Dimethyl Ether (DME) is considered a clean alternative fuel to diesel due to its soot-free combustion characteristics and its capability to be produced from renewable energy sources rather than fossil fuels such as coal or petroleum. To mitigate the effect of strong wave dynamics on fuel supply lines caused due to the high compressibility of DME and to overcome its low lubricity, a hydraulically actuated electronic unit injector (HEUI) with pressure intensification was used. The study focuses on high pressure operation, up to 2000 bar, significantly higher than pressure ranges reported previously with DME. A one-dimensional HEUI injector model is built in MATLAB/SIMULINK graphical software environment, to predict the rate of injection (ROI) profile critical to spray and combustion characterization. The outputs of model are compared with experimental ROI and injection duration data of both diesel and DME at injection pressures ranging from 750 to 2000 bar for single-hole and multi-hole
Zhu, Xiucheng, Limbu, Sanjeet, Cung, Khanh, De Ojeda, William, Lee, Seong-Young
Modelling Ignition Processes of Palm Oil Biodiesel and Diesel Fuels Using a Two Stage Lagrangian Approach2015-01-186109/01/2015
Designing advanced combustion engines requires a better understanding of the physical and chemical processes occurring during spray combustion. In this study, the ignition characteristics of conventional diesel and palm biodiesel fuels were simulated using the two-stage Lagrangian (TSL) simulation, a zero dimensional (0-D) modeling technique. For the diesel fuel surrogate, a detailed chemical kinetic model for n-heptane from LLNL (Lawrence Livermore National Laboratory), with 550 chemical species and 2450 elementary reactions was utilized. For the palm biodiesel, detailed mechanism (4800 species and 2450 elementary reactions) for the 5 basic biodiesel components; methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate was used. Also, simulations were performed using a reduced mechanism (115 species and 460 reactions) for surrogates of palm oil biodiesel comprising mixtures of methyl decanoate, methyl decenoate and n-heptane. The simulated data were
Alfazazi, Adamu, Sarathy, Mani, Kuti, Olawole Abiola
Novel Ignition Property Measurements for Various Fuels using a Micro Flow Reactor with a Controlled Temperature Profile2015-01-181709/01/2015
This paper presents new methodology of ignition property measurements using a micro flow reactor with a controlled temperature profile, which is a spin-off methodology developed through microcombustion studies during the last decade. Stable multi-stage reaction zones were observed in low flow velocity regime for hydrocarbons and it was found that unsteady multi-stage oxidations of hydrocarbons were examined by stable multi-stage reaction zones termed as weak flames. This methodology has been further applied to various fuels. Effects of research octane number of primary reference fuels on weak flames were examined and it was shown that stabilized temperature levels and appearances of weak flames have apparent correlations with RON. Recent works using the micro flow reactor were also introduced.
Nakamura, Hisashi, Tezuka, Takuya, Hasegawa, Susumu, Maruta, Kaoru
Experimental and Kinetic Study on Ignition Delay Times of Diethyl Ether2015-01-089704/14/2015
Ignition delay times of Diethyl Ether (DEE) were measured behind reflected shock waves for the temperatures from 1050 to 1600 K, pressures of 1.2, 4 and 16 atm and equivalence ratios of 0.5 and 1.0. Result shows that the ignition delay times increase with the increase of the equivalence ratio and the decrease of the pressure. The only literature DEE mechanism (Yasunaga et al. model) was employed to simulate the experimental data and result shows that the model gives reasonable prediction on lean mixtures, while the prediction on stoichiometric mixtures is slightly higher. Sensitivity analysis was conducted to pick out the key reactions in the process of DEE ignition at high and low pressures, respectively. Reaction pathway analysis shows that the consumption of DEE is dominated by the H-abstraction reactions. Through linear analysis, a correlation for the DEE ignition data was obtained. Using this correlation, the measured DEE data were compared to the literature correlations of DME
Zhang, Zihang, Hu, Erjiang, Peng, Cheng, Huang, Zuohua
An Experimental Study of Injection and Combustion with Dimethyl Ether2015-01-093204/14/2015
DiMethyl Ether (DME) has been known to be an outstanding fuel for combustion in diesel cycle engines for nearly twenty years. DME has a vapour pressure of approximately 0.5MPa at ambient temperature (293K), thus it requires pressurized fuel systems to keep it in liquid state which are similar to those for Liquefied Petroleum Gas (mixtures of propane and butane). The high vapour pressure of DME permits the possibility to optimize the fuel injection characteristic of direct injection diesel engines in order to achieve a fast evaporation and mixing with the charged gas in the combustion chamber, even at moderate fuel injection pressures. To understand the interrelation between the fuel flow inside the nozzle spray holes tests were carried out using 2D optically accessed nozzles coupled with modelling approaches for the fuel flow, cavitation, evaporation and the gas dynamics of 2-phase (liquid and gas) flows. And to understand the spray characteristics tests were carried out using constant
Sasaki, Satoru, Kato, Masaaki, Yokota, Takamasa, Konno, Mitsuru, Gill, Denis
A Study of Supercharged HCCI Combustion Using Blended Fuels of Propane and DME2014-32-000511/11/2014
Homogeneous Charge Compression Ignition (HCCI) has attracted a great deal of interest as a combustion system for internal combustion engines because it achieves high efficiency and clean exhaust emissions. However, HCCI combustion has several issues that remain to be solved. For example, it is difficult to control engine operation because there is no physical means of inducing ignition. Another issue is the rapid rate of heat release because ignition of the mixture occurs simultaneously at multiple places in the cylinder. The results of previous investigations have shown that the use of a blended fuel of DME and propane was observed that the overall combustion process was delayed, with that combustion became steep when injected propane much. This study focused on expanding the region of stable engine operation and improving thermal efficiency by using supercharging and blended fuels. The purpose of using supercharging were in order to moderated combustion. In addition, the purpose of
Mochizuki, Keisuke, Shima, Takahiro, Suzuki, Hirotaka, Ishikawa, Yoshihiro, Iijima, Akira, Yoshida, Koji, Shoji, Hideo
Composition Effects on Thermo-Physical Properties and Evaporation of Suspended Droplets of Biodiesel Fuels2014-01-276010/13/2014
From the energy security and environment standpoint, the biodiesel fuels derived from vegetable oils or animal fats appear to be promising alternative to fossil diesel. Although the engine experiments prove their viability, the scientific data base for characterizing biodiesel combustion is limited. Detailed studies on the characterization of biodiesel fuels and their effects on fundamental engine processes like droplet evaporation and combustion are essential. The present study evaluates the useful thermo-physical properties and droplet evaporation characteristics of biodiesel fuels. The droplet evaporation measurements are carried out using suspended droplet experiments on five biodiesel fuels of Indian origin viz. jatropha, pongamia (karanja), neem, mahua and palm. The droplet evaporation rates of these fuels are related to properties such as binary diffusivity and molecular weight, which in turn depend on their fatty acid composition. It is observed that palm methyl ester has the
Manjunath, More, Prakash, Pratheesh, Raghavan, Vasudevan, Mehta, Pramod S.
An Investigation into the Effect of Fuel Injection System Improvements on the Injection and Combustion of DiMethyl Ether in a Diesel Cycle Engine2014-01-265810/13/2014
For nearly twenty years, DiMethyl Ether has been known to be an outstanding fuel for combustion in diesel cycle engines. Not only does it have a high Cetane number, it burns absolutely soot free and produces lower NOx exhaust emissions than the equivalent diesel. However, the physical properties of DME such as its low viscosity, lubricity and bulk modulus have negative effects for the fuel injection system, which have both limited the achievable injection pressures to about 500 bar and DME's introduction into the market. To overcome some of these effects, a common rail fuel injection system was adapted to operate with DME and produce injection pressures of up to 1000 bar. To understand the effect of the high injection pressure, tests were carried out using 2D optically accessed nozzles. This allowed the impact of the high vapour pressure of DME on the onset of cavitation in the nozzle hole to be assessed and improve the flow characteristics. CFD simulation was also used to assist in
Gill, Denis W., Ofner, Herwig, Stoewe, Carsten, Wieser, Karl, Winklhofer, Ernst, Kato, Masaaki, Yokota, Takamasa, Weber, Jost
The Analysis of Energy Conversion Efficiency in SI Engines for Selected Gaseous Fuels2014-01-269210/13/2014
The analysis of the overall performance of the engine powered by selected gaseous fuels has been presented in this paper. Primary objective of the research was to determine the influence of fuel type on efficiency of energy conversion in the tested engine. The scope of the research featured: application low-carbon fuels, use of DME as a renewable fuel in blends with LPG. The use of low-carbon gaseous fuels gives the opportunity to reduce exhaust gases emissions. The basic assumption in the presented research was the use of gaseous fuels, for which the main component is methane. The main problem taken into consideration was excessive duration of the combustion process, which is one of the causes of the engine overall efficiency reduction when running on gaseous fuels. This issue becomes even more important due to the lower heating value of natural gas (methane) when compared to conventional fuels. One of possible solutions is the use of fuel blends, e.g. methane-enriched hydrogen as an
Flekiewicz, Marek, Kubica, Grzegorz, Flekiewicz, Bartosz
Experimental Investigation on the Performance and Exhaust Emission of Biogas-Diesel Dual-Fuel Combustion in a CI Engine2014-01-268910/13/2014
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
Lounici, Mohand Said, Loubar, Khaled, Tazerout, Mohand, Balistrou, Mourad, Tarabet, Lyes
Effects of a Blend of Eethanol and Ethylene Glycol Dimethyl Ether on Fuel Properties and Engine Performances When Used as Clean Diesel Fuel Additive2014-01-277110/13/2014
In the present study, ethanol and EGDE were mixed in 1:1 proportion by volume to make a new oxygenate blend as a clean diesel fuel additive. Results showed that the oxygenate blend is miscible with diesel fuel within a wide proportion range above 0°C. With the increase in the content level of the oxygenate blend in diesel fuel, viscosity decreases near linearly, smoke point increases, closed flash point decreases rapidly below 5% of the oxygenate blend by volume in diesel fuel and then maintains unchanged with the oxygenate blend content increasing, and solidifying point of 0# diesel fuel decreases. When a engine was fueled with a diesel fuel added with 20% (v) of the oxygenate blend operating under partial load at 1800rpm and 2300rpm respectively, smoke emissions can be lessened by about 50% to 80%, and CO can be reduced by up to about 70%. NOx emissions generally increase slightly. Power output drops by 0.5%-1.5%, fuel consumption increases, while energy economy is enhanced by 1.8
Guo, Hejun, Zheng, Li
A Computational Study of the Effects of EGR and Intake-Pressure Boost on DME Autoignition Characteristics over Wide Ranges of Engine Speed2014-01-146104/01/2014
This study has been computationally investigated how the DME autoignition reactivity is affected by EGR and intake-pressure boost over various engine speed. CHEMKIN-PRO was used as a solver and chemical-kinetics mechanism for DME was utilized from Curran's model. We examined first the influence of EGR addition on autoignition reactivity using contribution matrix. Investigations concentrate on the HCCI combustion of DME at wide ranges of engine speeds and intake-pressure boost with EGR rates and their effects on variations of autoignition timings, combustion durations in two-stage combustion process in-detail including reaction rates of dominant reactions involved in autoignition process. The results show that EGR addition increases the combustion duration by lowering reaction rates. It was also found that autoignition timings were very sensitive to boost pressure due to boost pressure enhances the reactivity of intermediate species but combustion durations dominantly depend on the EGR
Jamsran, Narankhuu, Lim, Ocktaeck, Iida, Norimasa
Economics of Transportation Hydrocarbon Fuels and Environmental Regulations with Conceptual Solutions - Carbon-Neutral and Carbon-Negative Synfuels2014-01-194304/01/2014
Of all current proposals for sustainable transportation, the assumption is energy scarcity when there are economically favorable alternatives using existing technology. This paper explores the economics of a sustainable transportation energy pathway that provides carbon-neutral and carbon-negative synthetic fuel derived from seawater as the feedstock and power via Ocean Thermal Energy Cycle (OTEC). Seawater-based synthetic fuel is naturally carbon-neutral - different synthesis processes can yield hydrogen, methane, methanol and ethanol as well as gasoline, diesel or jet fuel - and is carbon-negative when combined with aquaculture. Methanol is favored as a fuel as it requires relatively lower capital investment; can be easily transported and stored; can be used as a feedstock to many chemical processes that currently rely on petrochemicals; and can be coproduced with or converted to dimethyl ether. This paper proposes a new process that for the first time marries OTEC-power and seawater
Bucknell, John R.
Effect of POMDME Blend on PAH Emissions and Particulate Size Distribution from an In-Use Light-Duty Diesel Engine2014-01-195104/01/2014
Polyoxymethylene dimethyl ether (POMDME) is a synthetic fuel from alternative energy sources, which can be blended in any ratio with petroleum diesel fuel. The regulated and non-regulated emissions, especially polyaromatic hydrocarbons (PAH) and particle number size distribution (PNSD), from an old Euro-3 diesel engine fueled with a 7,5% blend of POMDME in commercial diesel fuel were measured and compared to the base diesel fuel, after adjusting exhaust gas ratio (EGR) in order to match the level of NOx emission. The experimental results show a significant reduction in soot and particulate matter (PM) emissions. The number of particles smaller than 30 nm is slightly increased at low speed and low load operating conditions, while at high speed the number concentration of particles larger than 30 nm is reduced. The PAH emissions were found higher for the oxygenated fuel blend than for the base fuel. This result is consistent with the exhaust gas temperature profiles during the PAH
Pellegrini, Leonardo, Patrini, Renata, Marchionna, Mario
Novel Renewable Additive for Diesel Engines2014-01-126204/01/2014
A novel oxygenate, 5-methyl furoate ethyl ester (EF), was made by a chemical process from biomass and ethanol. This compound was then used as a renewable diesel additive at concentrations up to 10 percent by volume. This unique ester, which is similar in composition to a know food additive, was studied for engine performance in comparison with two other oxygenated alternatives (i.e. ethanol - EtOH and ethyl levulinate - EL) and with B20 (20 percent biodiesel). Tests were performed with a 2012 6.7 L Ford diesel engine using the heavy-duty Federal Test Procedure. The emission results indicated that a blend of the ester with diesel was comparable to the base fuel. In addition, the results also indicated that EF reduces the formation of particulate matter (PM) and carbon monoxide. Other properties of EF seem to improve the physical properties of the blended fuel such as lubricity and viscosity when compared to the base fuel.
Fanick, Robert E., Cahana, Aviad
Experimental and Modeling Study on Auto-Ignition of DME/n-Butane Blends under Engine Relevant Pressure2014-01-147004/01/2014
In this study, the ignition delay times of DME/n-C4H10 fuel blends (neat DME, 50/50 and neat n-C4H10) diluted with argon were measured behind reflected shock waves. The experiments were performed in the temperature range of 1250 - 1600 K, at pressure of 2.0 MPa and equivalence ratios from 0.5 to 2.0. A latest kinetic mechanism NUIG Aramco Mech 1.3 was validated against the present ignition data and used to conducted chemical kinetic analysis. Different equivalence-ratio-dependent was exhibited at different temperature regimes for DME, n-C4H10, and their blend. Fuel flux analysis, sensitive analysis and mole fraction analysis were carried out for understanding the interaction between the ignition chemistries of DME and n-C4H10.
Jiang, Xue, Zhang, YingJia, Pan, Lun, Man, XingJia, Huang, Zuohua
Numerical characterization of two alternative-to-diesel fuels using a moments spray model2014-01-142204/01/2014
The need to evaluate other fuel types for use in internal combustion engines has increased with the concerns related to the limited availability of fossil fuels and the need to reduce emissions. In this assessment, two alternative-to-diesel fuels, dimethyl ether and biodiesel, are characterized by their spray tip penetration at different axial distances from the nozzle tip and at different ambient pressure values. The sauter mean diameter values at various axial distances from the injector tip are also evaluated. A novel diesel spray model that presents the hydrodynamics features of sprays from the moments derived from a Gamma size distribution and the droplet-size distribution function, rather than from droplet-size classes, is used for the numerical predictions. The results indicate that the spray tip penetration for both fuels increases rapidly initially but the rate of increase slows at the later stages of the fuel injection. However, with increases in the ambient pressure values
Emekwuru, Nwabueze
Life Cycle Land Requirement, Energy Consumption and GHG Emissions of Biodiesel Derived from Microalgae and Jatropha curcas Seeds in China2014-01-196404/01/2014
The aim of this study is to evaluate the land requirement, energy consumption and GHG (greenhouse gases) emissions of microalgal biodiesel (M-BD) and Jatropha curcas seeds (J-BD) based biodiesel from the perspective of life cycle assessment (LCA). Mass and energy balance was used through the whole LCA calculation for each process. Two types of biodiesel (100% biodiesel: BD100, and 20% blends of biodiesel: BD20) were assumed to be combusted in the suitable diesel engine. Displacement method was adopted to measure the co-products credits. The results showed that the land requirement of producing 1 kg biodiesel from microalgae was about 1/31 of that from Jatropha curcas seeds. The well to pump (WTP) stage for microalgal biodiesel had higher fossil energy requirement but lower petroleum energy consumption and GHG emissions compared to Jatropha curcas and conventional diesel (CD). The WTP energy efficiency for J-BD100 and M-BD 100 were 26% and 17.4%, respectively. The feedstock growing
Zhang, Tingting, Xie, Xiaomin, Huang, Zhen
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