Browse Topic: Methane

Items (123)

A comparative study of ethanol and methanol blends on performance and emissions on BSIV and BSVI class of vehicles

2024-26-00731/16/2024

The quest for alternate fuels has led many researchers to evaluate various alcohols as an immediate substitute for gasoline. Among the alcohols, ethanol has received a lot of popularity as it can be produced from biomass feeds such as sugarcane and corn. Several countries have made it mandatory to blend at least 10% of ethanol in gasoline. However, the source of feedstock for ethanol production is posing a threat to food security. In order to restrain this problem, a few countries are promoting the use of methanol as an alternative fuel. Methanol can be obtained by processing naturally available biomass resources, much of which is waste material. Methanol-gasoline blends have been found to have a high octane number, good performance and lower carbon emissions, making it an excellent alternative fuel for engines. In the present study, a comparative analysis was carried out to evaluate the performance and emissions from unmodified vehicles using lower concentrations (up to 20%) of

Teja, Ravi, Khandai, Chinmayananda, Muralidharan, M

Design and Computational Investigations of Aerobot for Titan with maneuverability using momentum wheel and propeller equipped with droppable weather stations

2022-26-11915/26/2022

Titan, Saturn’s largest moon and the only celestial body which is found to have a landmass composed of liquid hydrocarbons. Nitrogen – The building block of all life that exists on earth is found to be abundant in Titan’s atmosphere of up to 97%. Aerobots provide a great platform for exploring a celestial body with an atmosphere such as Titan. They have modest power requirements, longer mission duration, and can cover a longer distance in a shorter time. They are powered by Radioisotope Thermoelectric Generator for optimal mission life. Aerobot’s altitude can be altered by varying the temperature of the air inside the balloon and yaw can be controlled using Reaction Wheel and a motor-driven propeller for forwarding thrust. The proposed Aerobot will be equipped with four miniature deployable fixed weather stations that can be dropped from the aerobot to titan’s surface. They can be deployed at diverse locations such as the equator and Polar Regions to deeply explore the Titan’s climate

Raja, Manoj Kumar, Sivasankaran, Abinash Nataraj, Saravana Mohan, Haribalan, Thangavel, Sabari, R, Vijayanandh, Gnanasekaran, Raj Kumar

Dragonfly : Defining Environments for Rotorcraft Flight on Titan

F-0076-2020-16301

10/5/2020

Dragonfly is an X-8 octocopter designed to explore Saturn's moon Titan, and is currently under development for launch in 2026. Titan is a uniquely favorable body for atmospheric flight, in that it has a low gravity (1/7 Earth's) and a dense atmosphere (4x Earth's) which reduce the energetic requirements for heavier-than-air flight. Dragonfly will make multiple (autonomous) flights over several years with ranges of the order of 10km to explore different sites on Titan. The key features of the Titan environment are reviewed. These include the characteristics of the landing site terrain, resembling dune fields in terrestrial deserts. Winds are generally very low, ∼ 1m/s. Stronger winds, and methane rainfall, can occur in rare rainstorms, but these are not expected at the latitude and season of Dragonfly's arrival. Brownout and triboelectric charging due to surface dust lofted by rotor downwash is possible, and these hazards and their mitigations are discussed.

Lorenz, Ralph

Cycle-Resolved Evaluation of Directly Injected Methane Using a High-Speed Laser-Induced Fluorescence Measurement System

2020-01-21069/15/2020

The usage of alternative fuels inside internal combustion engines (ICE), is one promising approach to meet the higher requirements concerning the efficiency and emission of modern combustion systems. The injection and mixture formation of such fuels has a major impact on the subsequent combustion as well as the formation of pollutants. To rate the influence and to gain a better understanding of those new alternatives a basic understanding of these dominant processes is mandatory. The principle of laser-induced fluorescence (LIF) is a well-known method to display and evaluate fuel distributions inside combustion chambers. A suiting online calibration routine allows the visualization of air-fuel equivalence ratio (λ) two-dimensionally during different operation modes. As cyclic variations can become a more critical issue while using alternative fuels, cycle- resolved test series become more and more important. To obtain several crank-angle-resolved measurements during one cycle as well

Geiger, Mirko, Zoellner, Christian, Brueggemann, Dieter

Numerical Investigation of In-Cylinder Tumble/Swirl Flow on Mixing, Turbulence and Combustion of Methane in SI Engine

2020-01-20139/15/2020

In the present work, the in-cylinder tumble/swirl flow and its effect on the homogeneity, turbulence, and combustion of methane are investigated in a canted valve engine using ANSYS. The study is focused on the impact of initial swirl and tumble on the charge preparation, turbulent kinetic energy, and combustion of methane. The flow simulation was performed in ANSYS using hybrid mesh for cold flow simulation to study the tumble/swirl flow variation. For combustion simulation, a 2D axisymmetric model was used with an initial swirl and tumble ratio for studying the effect on premixed combustion. The flow simulation was performed for suction and compression to see the variation in the swirl and tumble with crank position and engine speed. The combustion simulation was performed only for compression and power stroke to save the computation time. The results depict that the flow inside the cylinder plays a significant role in the preparation of a homogeneous charge. Tumble/swirl mainly

Yadav, Neeraj Kumar, Saxena, Mohit Raj, Maurya, Rakesh Kumar

Performance of Bi-Fuel Ethanol-Methane SI-Engine for Stage V Non-Road Applications

2020-01-20439/15/2020

Due to agricultural engines’ high average workload and operation in rural areas, substituting internal combustion engines in non-road sector is still a challenge. Utilizing sustainable solutions are therefore in key position for decarbonizing the non-road sector. To this day, the diesel engines dominate the markets because of their high efficiency. However, the simplicity and cost effectiveness of the spark-ignited engines together with renewable fuels are suggested to bring several advantages compared to the diesel engine. E.g. ethanol and bio methane are relatively simple to produce from agricultural residuals and wastes, and the raw materials are easily available around the world. Additionally, stoichiometric engines would only require a three-way catalyst (TWC) to fulfil Stage V emission regulations. A bi-fuel (BF) and dual-fuel (DF) engine operating on both ethanol and biogas could potentially offer a flexible option for e.g. farmers, as they could produce the fuels locally and

Pettinen, Rasmus, Soderena, Petri, Westerholm, Mårten, Nyyssönen, Sami, Söderström, Christer, Martikainen, Jarno

An Experimental Investigation on Aldehyde and Methane Emissions from Hydrous Ethanol and Gasoline Fueled SI Engine

2020-01-20479/15/2020

Use of ethanol as gasoline replacement can contribute to the reduction of nitrogen oxide (NOx) and carbon oxide (CO) emissions. Depending on ethanol production, significant reduction of greenhouse-gas emissions is possible. Concentration of certain species, such as unburned ethanol and acetaldehyde in the engine-out emissions are known to rise when ratio of ethanol to gasoline increases in the fuel. This research explores on hydrous ethanol fueled port-fuel injection (PFI) spark ignition (SI) engine emissions that contribute to photochemical formation of ozone, or so-called ozone precursors and the precursor of peroxyacetyl nitrates (PANs). The results are compared to engine operation on gasoline. Concentration obtained by FTIR gas analyzer, and mass-specific emissions of formaldehyde (HCHO), acetaldehyde (MeCHO) and methane (CH4) under two engine speed, four load and two spark advance settings are analyzed and presented. Combustion phasing results based on in-cylinder pressure

Gailis, Maris, Pirs, Vilnis, Jansons, Marcis, Birzietis, Gints, Dukulis, Ilmars

Narrow-Throat Pre-Chamber Combustion with Ethanol, a Comparison with Methane

2020-01-20419/15/2020

With increasingly stringent emissions regulations, the use of pre-chamber combustion systems is gaining popularity in Internal Combustion Engines (ICE). The advantages of pre-chambers are well established, such as improving fuel economy by increasing the lean limit and reducing emissions, particularly NOX. In pre-chamber combustion, flame jets shoot out from the pre-chamber orifices into the main chamber, generating several ignition points that promote a rapid burn rate of the lean mixture (excess-air ratio (λ) >1) in the main chamber. This work studies the effects of using two different fuels in the main chamber and assesses the lean limit, the combustion efficiency (ηc), and the emissions of a single-cylinder heavy-duty engine equipped with a narrow-throat active pre-chamber. Ethanol (C2H5OH) was tested in the main chamber while keeping the pre-chamber fueled with methane (CH4), and the results were then compared to using methane as the sole fuel. The engine was operated at a fixed

Almatrafi, Fahad, Hlaing, Ponnya, Echeverri Marquez, Manuel, Ben Houidi, Moez, Johansson, Bengt

Experimental and Numerical Characterization of High-Pressure Methane Jets for Direct Injection in Internal Combustion Engines

2020-01-21249/15/2020

Compressed Natural Gas (CNG) is regarded as a promising fuel for spark-ignited (SI) internal combustion engines (ICE) to improve engine thermal efficiency and reduce both carbon dioxide and pollutant emissions. Significant advantages of CNG are higher-octane number, higher hydrogen to carbon ratio, and lower energy-specific CO2 emissions compared with gasoline. More, it can be produced in renewable ways, and is more widespread and cheaper than conventional liquid fossil fuels. In this regard, the direct injection of CNG engines can be considered a promising technology for highly efficient and low-emission future engines. This work reports an experimental and numerical characterization of high-pressure methane jets from a multi-hole injector for direct injection engines. The tests were performed in a constant volume (CV) combustion chamber under a broad range of operating conditions in terms of injection pressure, in the range 1.0 - 5.0 MPa, and ambient back-pressure in between 0.05 to

Montanaro, Alessandro, Allocca, Luigi, De Vita, Angelo, Ranieri, Stefano, Duronio, Francesco, Meccariello, Giovanni

High-Speed Imaging of Main-Chamber Combustion of a Narrow Throat Pre-Chamber under Lean Conditions

2020-01-20819/15/2020

Pre-chamber combustion (PCC) allows an extension on the lean limit of an internal combustion engine (ICE). This combustion mode provides lower NOx emissions and shorter combustion durations that lead to a higher indicated efficiency. In the present work, a narrow throat pre-chamber was tested, which has a unique nozzle area distribution in two rows of six nozzle holes each. Tests were carried out in a modified heavy-duty engine for optical visualization. Methane was used as fuel for both the pre-chamber and the main chamber. Seven operating points were tested, including passive pre-chamber mode as a limit condition, to study the effect of pre- and main-chamber fuel addition on the pre-chamber jets and the main chamber combustion via chemiluminescence imaging. A typical cycle of one of the tested conditions is explained through the captured images. Observations of the typical cycle reveal a predominant presence of only six jets (from the lower row), with well-defined jet structures. A

Echeverri Marquez, Manuel, Hlaing, Ponnya, Tang, Qinglong, Sampath, Ramgopal, Cenker, Emre, Ben Houidi, Moez, Magnotti, Gaetano, Johansson, Bengt

Simultaneous Negative PLIF and OH* Chemiluminescence Imaging of the Gas Exchange and Flame Jet from a Narrow Throat Pre-Chamber

2020-01-20809/15/2020

Pre-chamber combustion (PCC) is a promising engine combustion concept capable of extending the lean limit at part load. The engine experiments in the literature showed that the PCC could achieve higher engine thermal efficiency and much lower NOx emission than the spark-ignition engine. Improved understanding of the detailed flow and combustion physics of PCC is important for optimizing the PCC combustion. In this study, we investigated the gas exchange and flame jet from a narrow throat pre-chamber (PC) by only fueling the PC with methane in an optical engine. Simultaneous negative acetone planar laser-induced fluorescence (PLIF) imaging and OH* chemiluminescence imaging were applied to visualize the PC jet and flame jet from the PC, respectively. Results indicate a delay of the PC gas exchange relative to the built-up of the pressure difference (△ P) between PC and the main chamber (MC). This should be due to the gas inertia inside the PC and the resistance of the PC nozzle. The PC

Tang, Qinglong, Sampath, Ramgopal, Echeverri Marquez, Manuel, Hlaing, Ponnya, Sharma, Priybrat, Ben Houidi, Moez, Cenker, Emre, Chang, Junseok, Magnotti, Gaetano, Johansson, Bengt

In-Situ Resource Utilization (ISRU): Methylotrophic Microorganisms Expressing Soluble Methane Monooxygenase Proteins

TBMG-358121/1/2020

Long-duration missions to planetary bodies and deep space will require new technological developments that support human habitation in transit and on distant bodies. Microorganisms are unique from the standpoint that they can be employed as self-replicating bio-factories to produce both native and engineered mission-relevant bio-products. Methane (CH4) usage in In-Space Manufacturing (ISM) platforms has been discussed previously for human exploration and has been proposed to be used in physicochemical systems as a propulsion fuel, supply gas, and in fuel cells.

Methane Detector Sniffs Out Leaks

TBMG-351569/1/2019

Methane is everywhere on Earth. It’s the main ingredient in the natural gas that powers heating, cooking, and electricity. It’s also a potent greenhouse gas. The presence of methane is also interesting for a different reason: because the biggest source of the gas on Earth is bacterial life. That means when NASA planetary scientists caught a glimpse of it on Mars, it merited a closer look.

Mobile, Dual-Comb Device for Methane Leak Detection

TBMG-351459/1/2019

Accurately detecting, locating, and quantifying leaks of methane — the main component of natural gas and a major fuel source worldwide — is critically important for both environmental and economic reasons. Unfortunately, traditional methods are slow, labor-intensive, limited to small coverage areas, and expensive to operate over time.

A Study on the Combustion Characteristics of a Methane Jet Flame in a Pressurized Hot Vitiated Co-flow

2019-01-00821/15/2019

This work presents the study of the methane jet flame in a pressurized vitiated co-flow burner (PVCB). The lift-off length and the stabilization of the methane jet flame under different environment pressures, co-flow temperatures, co-flow rates and jet velocities have been studied, and a chemical numerical simulation based on Gri-mech 3.0 was analyzed as well. The results could provide theoretical supports for the research of natural gas engine combustion stabilization control to increase its thermal efficiency. The experimental results show that the lift-off length decreases obviously (104.22mm to76.14mm) with the increase of the environment pressure (1to1.5bar, 1073K) and temperature (119.34mm to 43.74mm from 1058K to 1118K, 1bar), meanwhile, it also increases with the increment of the co-flow rate and jet velocity. The stabilization of the lift-off length tends to be better and the methane jet flame tends to be brighter with the lift-off length decreasing under all operation

Qin, Qiushi, Xie, Wei, Pan, Kaifeng, Deng, Jun, Li, Liguang, Wu, Zhijun

The Use of Ozone in Low Temperature Methane Control for Natural Gas Applications

2018-01-17029/10/2018

Lean operating natural gas heavy duty applications have advantages in terms of lower CO2 and PM compared to Diesel applications. This makes operating heavy duty applications on natural gas attractive and currently, they do not have to implement an exhaust particulate filter. However, the challenge is controlling methane emissions over a range of vehicle operating conditions. Methane is extremely stable and light off occurs at temperatures above 400 °C, with high efficiency occurring >500 °C and requires high precious metal loaded catalysts in the range of 150 - 200 g/ft3. Under stoichiometric conditions, 500 °C can be met in many engine operating points however, for lean operating applications, the exhaust temperature can be significantly lower than 500 °C posing a significant challenge for exhaust catalytic CH4 control. This paper will discuss synthetic gas reactor study results using ozone in the feed gas to perform low temperature methane control. A range of catalysts were

Keenan, Matthew, Nicole, Jacques, Poojary, Damodara

CFD Analysis of the Combustion Process in Dual-Fuel Diesel Engine

2018-01-02574/3/2018

Dual-fuel technology has the potential to offer significant improvements in the emissions of carbon dioxide from light-duty compression ignition engines. The dual-fuel (diesel/natural gas) concept represents a possible solution to reduce emissions from diesel engines by using natural gas (methane) as an alternative fuel. Methane was injected in the intake manifold while the diesel oil was injected directly into the engine. The present work describes the results of a numerical study on combustion process of a common rail diesel engine supplied with natural gas and diesel oil. In particular, the aim is to study the effect of increasing methane concentration at constant injected diesel amount on both pollutant emissions and combustion evolution. The study of dual-fuel engines that is carried out in this paper aims at the evaluation of the CFD potential, by a 3-dimensional code, to predict the main features of this technology. In fact, to better understand the phenomena that take place

Mancaruso, Ezio, Sequino, Luigi, Vaglieco, Bianca Maria, Cameretti, Maria Cristina, De Robbio, Roberta, Tuccillo, Raffaele

An Optical Characterization of Dual-Fuel Combustion in a Heavy-Duty Diesel Engine

2018-01-02524/3/2018

Dual fuel (DF) combustion technology as a feasible approach controlling engine-out emissions facilitates the concept of fuel flexibility in diesel engines. The abundance of natural gas (90-95% methane) and its relatively low-price and the clean-burning characteristic has attracted the interest of engine manufacturers. Moreover, with the low C/H ratio and very low soot producing tendency of methane combined with high engine efficiency makes it a viable primary fuel for diesel engines. However, the fundamental knowledge on in-cylinder combustion phenomena still remains limited and needs to be studied for further advances in the research on DF technology. The objective of this study is to investigate the ignition delay with the effect of, 1) methane equivalence ratio, 2) intake air temperature and 3) pilot ratio on the diesel-methane DF-combustion. Combustion phenomenon was visualized in a single cylinder heavy-duty diesel engine modified for DF operations with an optical access. The high

Ahmad, Zeeshan, Aryal, Janak, Ranta, Olli, Kaario, Ossi, Vuorinen, Ville, Larmi, Martti

Experimental Study on Combustion Characteristics of Methane/Gasoline Dual-Fuel in a SI Engine at Different Load Conditions

2018-01-11404/3/2018

Methane as an attractive alternative fuel offers the most potential in clean combustion and low CO2 emissions. In this work, combustion characteristics of methane/gasoline dual-fuel were investigated in a spark-ignited engine with port-injection of methane and direct-injection of gasoline, allowing for variations in methane addition and excess air coefficient. Engine experimental results showed that under low load conditions, as methane mass rate was raised, there was a promotion in methane/gasoline dual-fuel combustion, and this became more obvious at lean conditions. Similar observations were also obtained when the engine was operated at intermediate load conditions, but a prolonged combustion duration was found with the methane addition. Further analysis showed that the promotion of methane/gasoline dual-fuel combustion with methane addition mainly occurred in the early stage of combustion, especially for lean conditions. Under large load conditions, methane addition showed good

Pan, Jiaying, Wei, Haiqiao, Shu, Ge-Qun, Feng, Dengquan

Study on Auto-Ignition Characteristics of High Pressure Methane Jet for Compression Ignition Engine Application

2018-01-02744/3/2018

Natural gas has been considered as an alternative fuel for a heavy duty diesel engine with its lower pollutant and carbon dioxide emissions than its counterpart. However, due to the high auto-ignition temperature of methane, this alternate fuel has been mainly used in spark-ignited engine with relatively lower compression ratio, losing full potential of achieving high efficiency. To overcome these limitations, high-pressure direct injection of the natural gas in a compression ignition engine has been proposed, and there have been several attempts to understand physical behaviors and ignition of methane jet. In this study, auto-ignition characteristics of high-pressure methane jet were investigated both through the experiment and the multi-zone modeling to suggest the applicability to such engine. In the experiments, constant volume combustion chamber equipped with a single-hole, gasoline-direct-injector was used to understand the jet behavior and the ignition characteristic of the high

Lee, Tae Kyung, Min, Hyungeun, Song, Han Ho

Investigation of Combustion Knock Distribution in a Boosted Methane-Gasoline Blended Fueled SI Engine

2018-01-02154/3/2018

The characteristics of combustion knock metrics over a number of engine cycles can be an essential reference for knock detection and control in internal combustion engines. In a Spark-Ignition (SI) engine, the stochastic nature of combustion knock has been shown to follow a log-normal distribution. However, this has been derived from experiments done with gasoline only and applicability of log-normal distribution to dual-fuel combustion knock has not been explored. To evaluate the effectiveness and accuracy of log-normal distributed knock model for methane-gasoline blended fuel, a sweep of methane-gasoline blend ratio was conducted at two different engine speeds. Experimental investigation was conducted on a single cylinder prototype SI engine equipped with two fuel systems: a direct injection (DI) system for gasoline and a port fuel injection (PFI) system for methane. The experiments were conducted at 1500 rpm and 2000 rpm, 12.0 bar net indicated mean effective pressure wherein the

Yang, Zhuyong, Rao, Sandesh, Wang, Yanyu, Harsulkar, Jaideep, Ansari, Ehsan, Miganakallu Narasimhamurthy, Niranjan, Dice, Paul, Naber, Jeffrey, Lonari, Yashodeep, Szwaja, Stanislaw

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

2018-01-0258

4/3/2018

The sooting propensity of dual-fuel combustion with n-dodecane pilot injection in a lean-premixed methane-air charge has been investigated using an optically accessible Rapid Compression-Expansion Machine (RCEM) to achieve engine-relevant pressure and temperature conditions at the start of pilot injection. A Diesel injector with a 100 μm single-hole coaxial nozzle, mounted at the cylinder periphery, has been employed to admit the pilot fuel. The aim of this study was to enhance the fundamental understanding of soot formation and oxidation processes of n-dodecane in the presence of methane in the air charge by parametric variation of methane equivalence ratio, charge temperature, and pilot fuel injection duration. The influence of methane on ignition delay and flame extent of the pilot fuel jet has been determined by simultaneous excited-state hydroxyl radical (OH*) chemiluminescence and Schlieren imaging. The sooting behavior of the flame has been characterized using the 2D-DBI imaging

Srna, Aleš, Bruneaux, Gilles, von Rotz, Beat, Bombach, Rolf, Herrmann, Kai, Boulouchos, Konstantinos

Experimental and Kinetic Analyses of Thermochemical Fuel Reforming (TFR) with Alcohol Enrichment in Plug Flow Reactor: a Verification of In-Cylinder TFR

2017-01-227810/8/2017

In-cylinder thermochemical fuel reforming (TFR) in spark ignition natural gas engine was developed to reveal that thermochemical fuel reforming could increase H2 and CO concentration in reformed gas, leading to an increase of thermal efficiency and engine performance. Moreover, ethanol enrichment has been proved to have great potential to optimize TFR performance. In order to explain TFR phenomenon chemically, methane oxidation experiments were conducted in a laminar flow reactor with addition of ethanol and methanol at equivalent ratios of 1.5, 1.7, 1.9 and 2.1 from 948K to 1098K at atmospheric pressure. Experimental results showed that methanol have great ability to facilitate the oxidation of methane than that of ethanol. Meanwhile, the degree of methane conversion became more significantly as the equivalent ratio increased. Kinetic analysis of oxidation of methane with alcohol enrichment in a plug flow model was also conducted in this study. There was good agreement between

Deng, Zhiwei, Li, Ang, Zhu, Lei, Huang, Zhen

A Numerical Study on the Effects of the Orifice Geometry between Pre- and Main Chamber for a Natural Gas Engine

2017-01-219510/8/2017

The spark-ignited pre-chamber stratified combustion system is one of the most effective ways of expanding lean-burn ability and improving the performance of a natural gas engine. For these pre-chamber engines, the geometrical structure of orifices between the pre- and main chamber plays a significant role on the gas flow and flame propagation behaviors. The present study aims to investigate the effects of orifice number and diameter on combustion characteristics of a Shengdong T190 natural gas engine through CFD simulation. Various geometrical structures for the pre-chamber orifices were designed, offering variations in the number of orifices (4 to 8), and in the diameter of orifices (1.6mm to 2.9mm). A non-dimensional parameter β was employed to characterize the relative flow area of the orifices in the design. CFD simulations of combustion processes for these designs were carried out using a simplified chemical reaction kinetic mechanism for methane. Results show that, for a constant

Wang, Mei, Leng, Xianyin, He, Zhixia, Wei, Shengli, Chen, Liang, Jin, Yu

Direct Numerical Simulation of Methane Turbulent Premixed Oxy-Fuel Combustion

2017-01-219210/8/2017

A 3-D DNS (Three-Dimensional Direct Numerical Simulation) study with detailed chemical kinetic mechanism of methane has been performed to investigate the characteristics of turbulent premixed oxy-fuel combustion in the condition relevant to Spark Ignition (SI) engines. First, 1-D (one-dimensional) laminar freely propagating premixed flame is examined to show a consistent combustion temperature for different dilution cases, such that 73% H2O and 66% CO2 dilution ratios are adopted in the following 3-D DNS cases. Four 3-D DNS cases with various turbulence intensities are conducted. It is found that dilution agents can reduce the overall flame temperature but with an enhancement of density weighted flame speed. CO2 dilution case shows the lowest flame speed both in turbulent and laminar cases. Reaction path analysis based on an in-house post-processing tool is performed to show that the chemical effect of dilution agent H2O leads to an increase of the key elementary reactions; however the

Zhong, Shenghui, Peng, Zhijun, Li, Yu, Li, Hailin, Zhang, Fan

Efficiency and Emissions Characteristics of Partially Premixed Dual-Fuel Combustion by Co-Direct Injection of NG and Diesel Fuel (DI ² ) - Part 2

2017-01-07663/28/2017

The CO2 advantage coupled with the low NOX and PM potential of natural gas (NG) makes it well-suited for meeting future greenhouse gas (GHG) and NOX regulations for on-road medium and heavy-duty engines. However, because NG is mostly methane, reduced combustion efficiency associated with traditional NG fueling strategies can result in significant levels of methane emissions which offset the CO2 advantage due to reduced efficiency and the high global warming potential of methane. To address this issue, the unique co-direct injection capability of the Westport HPDI fuel system was leveraged to obtain a partially-premixed fuel charge by injecting NG during the compression stroke followed by diesel injection for ignition timing control. This combustion strategy, referred to as DI2, was found to improve thermal and combustion efficiencies over fumigated dual-fuel combustion modes. In addition, DI2 provided significant thermal efficiency improvement over the baseline diffusion-controlled

Neely, Gary D., Florea, Radu, Miwa, Jason, Abidin, Zainal

Correlation between Simulated Volume Fraction Burned Using a Quasi-Dimensional Model and Flame Area Measured in an Optically Accessible SI Engine

2017-01-05453/28/2017

Multi-fuel operation is one of the main topics of investigative research in the field of internal combustion engines. Spark ignition (SI) power units are relatively easily adaptable to alternative liquid-as well as gaseous-fuels, with mixture preparation being the main modification required. Numerical simulations are used on an ever wider scale in engine research in order to reduce costs associated with experimental investigations. In this sense, quasi-dimensional models provide acceptable accuracy with reduced computational efforts. Within this context, the present study puts under scrutiny the assumption of spherical flame propagation and how calibration of a two-zone combustion simulation is affected when changing fuel type. A quasi-dimensional model was calibrated based on measured in-cylinder pressure, and numerical results related to the two-zone volumes were compared to recorded flame imaging. Gasoline, ethanol, methane and hydrogen were used as fuels and the aforementioned

Irimescu, Adrian, Di Iorio, Silvana, Merola, Simona Silvia, Sementa, Paolo, Vaglieco, Bianca Maria

Parametric Analysis of Compression Ratio Variation Effects on Thermodynamic, Gaseous Pollutant and Particle Emissions of a Dual-Fuel CH ₄ -Diesel Light Duty Engine

2017-01-07643/28/2017

The paper reports the results of an experimental campaign aimed to assess the impact of the compression ratio (CR) variation on the performance and pollutant emissions, including the particle size spectrum, of a single cylinder research engine (SCE), representatives of the engine architectures for automotive application, operated in dual-fuel methane-diesel mode. Three pistons with different bowl volumes corresponding to CR values of 16.5, 15.5 and 14.5 were adopted for the whole test campaign. The injection strategy was based on two injection pulses per cycle, as conventionally employed for diesel engines. The test methodology per each CR included the optimization of both 1st injection pulse quantity and intake air mass flow rate in order to lower as much as possible the unburned methane emissions (MHC). The testing points were selected in order to analyse the CR impact on SCE performance at partial and high loads, including the performance estimation over the New European Driving

Di Blasio, Gabriele, Belgiorno, Giacomo, Beatrice, Carlo

Surface Functional Groups and Graphitization Degree of Soot in the Sooting History of Methane Premixed Flame

2017-01-10033/28/2017

The evolution of surface functional groups (SFGs) and the graphitization degree of soot generated in premixed methane flames are studied and the correlation between them is discussed. Test soot samples were obtained from an optimized thermophoretic sampling system and probe sampling system. The SFGs of soot were determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) after removing the soluble impurities from the soot samples, while the graphitization degree of soot was characterized by Raman spectrum and electron energy loss spectroscopy (EELS). The results reveal that the number of aliphatic C-H groups and C=O groups shows an initial increase and then decrease in the sooting history. The large amount of aliphatic C-H groups and small amount of aromatic C-H groups in the early stage of the soot mass growth process indicate that aliphatic C-H groups make a major contribution to the early stage of soot mass growth. The higher

Liu, Ye, Lv, Gang, Fan, Chenyang, Li, Na, Wang, Xiaowei

CFD Modeling and Experimental Analysis of a Homogeneously Charged Turbulent Jet Ignition System in a Rapid Compression Machine

2017-01-05573/28/2017

Three dimensional numerical simulation of the transient turbulent jet and ignition processes of a premixed methane-air mixture of a turbulent jet ignition (TJI) system is performed using Converge computational software. The prechamber initiated combustion enhancement technique that is utilized in a TJI system enables low temperature combustion by increasing the flame propagation rate and therefore decreasing the burn duration. Two important components of the TJI system are the prechamber where the spark plug and injectors are located and the nozzle which connects the prechamber to the main chamber. In order to model the turbulent jet of the TJI system, RANS k-ε and LES turbulent models and the SAGE chemistry solver with a reduced mechanism for methane are used. This research aims to give further insight into the turbulent jet flow in the TJI system by showing the numerical results of the jet temperature, turbulent kinetic energy and pressure which is compared to corresponding

Gholamisheeri, Masumeh, Thelen, Bryce, Toulson, Elisa

The Effects of Charge Preparation, Fuel Stratification, and Premixed Fuel Chemistry on Reactivity Controlled Compression Ignition (RCCI) Combustion

2017-01-07733/28/2017

Engine experiments were conducted on a heavy-duty single-cylinder engine to explore the effects of charge preparation, fuel stratification, and premixed fuel chemistry on the performance and emissions of Reactivity Controlled Compression Ignition (RCCI) combustion. The experiments were conducted at a fixed total fuel energy and engine speed, and charge preparation was varied by adjusting the global equivalence ratio between 0.28 and 0.35 at intake temperatures of 40°C and 60°C. With a premixed injection of isooctane (PRF100), and a single direct-injection of n-heptane (PRF0), fuel stratification was varied with start of injection (SOI) timing. Combustion phasing advanced as SOI was retarded between -140° and -35°, then retarded as injection timing was further retarded, indicating a potential shift in combustion regime. Peak gross efficiency was achieved between -60° and -45° SOI, and NOx emissions increased as SOI was retarded beyond -40°, peaking around -25° SOI. Optimal cases in

DelVescovo, Dan, Kokjohn, Sage, Reitz, Rolf

A Study of HCCI Operating Range Expansion by Applying Reaction Characteristics of Low-Carbon Alternative Fuels

2016-32-001111/8/2016

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

Characterization and Potential of Premixed Dual-Fuel Combustion in a Heavy Duty Natural Gas/Diesel Engine

2016-01-07904/5/2016

Natural Gas (NG) is currently a cost effective substitute for diesel fuel in the Heavy-Duty (HD) diesel transportation sector. Dual-Fuel engines substitute NG in place of diesel for decreased NOx and soot emissions, but suffer from high engine-out methane (CH4) emissions. Premixed Dual-Fuel Combustion (PDFC) is one method of decreasing methane emissions and simultaneously improving engine efficiency while maintaining low NOx and soot levels. PDFC utilizes an early diesel injection to adjust the flammability of the premixed charge, promoting more uniform burning of methane. Engine experiments were carried out using a NG and diesel HD single cylinder research engine. Key speeds and loads were explored in order to determine where PDFC is effective at reducing engine-out methane emissions over Conventional Dual-Fuel which uses a single diesel injection for ignition. PDFC has shown significant reductions in methane as well as CO emissions when compared with Conventional Dual-Fuel combustion

May, Ian, Pedrozo, Vinícius, Zhao, Hua, Cairns, Alasdair, Whelan, Steve, Wong, Hoi, Bennicke, Paul

Numerical Investigation of Spark Ignition Events in Lean and Dilute Methane/Air Mixtures Using a Detailed Energy Deposition Model

2016-01-06094/5/2016

It is beneficial but challenging to operate spark-ignition engines under highly lean and dilute conditions. The unstable ignition behavior can result in downgraded combustion performance in engine cylinders. Numerical approach is serving as a promising tool to identify the ignition requirements by providing insight into the complex physical/chemical phenomena. An effort to simulate the early stage of flame kernel initiation in lean and dilute fuel/air mixture has been made and discussed in this paper. The simulations are set to validate against laboratory results of spark ignition behavior in a constant volume combustion vessel. In order to present a practical as well as comprehensive ignition model, the simulations are performed by taking into consideration the discharge circuit analysis, the detailed reaction mechanism, and local heat transfer between the flame kernel and spark plug. The energy profile and the energy source geometry are investigated in detail to represent the physics

Zhang, Anqi, Scarcelli, Riccardo, Lee, Seong-Young, Wallner, Thomas, Naber, Jeffrey

Numerical Simulation of Heat Transfer Characteristics of Swirling Turbulent Flame Impinging on Flat Surface

2016-01-13404/5/2016

This paper presents a CFD simulation methodology for solving complex physics of methane/air swirling turbulent flame impinging on a flat surface. Turbulent Flow in burner is simulated using Re-Normalized Group k-ε model while Stress-omega Reynolds Stress Model is used for flame structure. Methane/air combustion is simulated using global combustion reaction mechanism. To account for Turbulence-Chemistry Interaction of methane/air combustion, Eddy - Dissipation Model is used. The effect of varying plate distance to burner exit nozzle diameter is also investigated and comparisons of simulated results with experiments are discussed. Change in flame structure is observed with variation of plate distance from burner exit. A dip in the heat flux distribution is observed for all cases. This is due to the presence of central weak flow region created at and around the central axis due to swirl.

Dang, Vikram, Chander, Subhash

Advanced Infrared Camera Maps Methane "Hot Spots"

TBMG-243003/1/2016

Methane often appears in the atmosphere at an irregular rate, puzzling researchers challenged with the task of tracking the gas’s sources in the landscape. An advanced infrared camera developed by Linköping University and Stockholm University researchers, in collaboration with the infrared imaging manufacturer Telops, allows users to both film and photograph methane emissions.

Domain-Engineered Magnesium-Oxide-Doped Lithium Niobate for Lidar-Based Remote Sensing

TBMG-224287/1/2015

There are several frequency conversion applications associated with lidar-based remote sensing that would benefit from the use of high-quality, complex (i.e., chirped, multi-section, or otherwise modulated) domain-engineered magnesiumoxide- doped lithium niobate (MgO:LN). While congruently melting lithium niobate (CLN) has been explored in detail over the last decades, it is known to be highly susceptible to photorefractive damage, which has limited the achievable performance of some QPM-assisted (quasi phase matching) structures that are commercially available. The demand for high-performance engineered nonlinear optical (NLO) materials, in terms of power handling, efficiency, conversion bandwidth, and accessible wavelength range, has driven the development of high-quality, large-area wafers of MgO:LN. While commercial outlets for these materials exist, there is still a need to expand the achievable performance of these structures (i.e. larger aperture bulk structures, higher

Non-Thermal, Plasma-Assisted Catalytic Reactor for CO2 Methanation

TBMG-22413

7/1/2015

Converting in-situ resources such as CO2, which is the main component of the Mars atmosphere, into methane for rocket propellants can significantly reduce the cost and risk of human exploration while at the same time enabling new mission concepts and long-term exploration sustainability. Methanation of CO2, also called a Sabatier reaction, is hence a key enabling technology required for sustainable and affordable human exploration of Mars.

NASA, UCF Professor Send Sensor to Stratosphere

TBMG-221425/1/2015

Planetary Atmospheres Minor Species Sensor (PAMSS) University of Central Florida Orlando, FL

Study of an On-board Fuel Reformer and Hydrogen-Added EGR Combustion in a Gasoline Engine

2015-01-09024/14/2015

To improve the fuel economy via high EGR, combustion stability is enhanced through the addition of hydrogen, with its high flame-speed in air-fuel mixture. So, in order to realize on-board hydrogen production we developed a fuel reformer which produces hydrogen rich gas. One of the main issues of the reformer engine is the effects of reformate gas components on combustion performance. To clarify the effect of reformate gas contents on combustion stability, chemical kinetic simulations and single-cylinder engine test, in which hydrogen, CO, methane and simulated gas were added to intake air, were executed. And it is confirmed that hydrogen additive rate is dominant on high EGR combustion. The other issue to realize the fuel reformer was the catalyst deterioration. Catalyst reforming and exposure test were carried out to understand the influence of actual exhaust gas on the catalyst performance. Fresh catalyst showed good performance in generating hydrogen, but an aged catalyst generated

Ashida, Koichi, Maeda, Hirofumi, Araki, Takashi, Hoshino, Maki, Hiraya, Koji, Izumi, Takao, Yasuoka, Masayuki

Fuel-Independent Particulate Emissions in an SIDI Engine

2015-01-10814/14/2015

The fuel-independent particulate emissions of a direct injection gasoline engine were investigated. This was done by running the engine with reference gasoline at four different loads and then switching to hydrogen or methane port fuel operation and comparing the resulting particulate emissions and their size distribution. Differences in the combustion characteristics of hydrogen and gasoline were accounted for by diluting the inlet air with nitrogen and matching the pressure or heat release traces to those of gasoline operation. Methane operation is expected to generate particulate emissions lower by several orders of magnitude compared to gasoline and hydrogen does not contribute to carbon soot formation because of the lack of carbon atoms in the molecule. Thus, any remaining particulate emissions at hydrogen gas operation must arise from non fuel related sources, e.g. from lubrication oil, metal abrasion or inlet air. With methane and hydrogen operation, only a very small amount of

Maier, Axel, Klaus, Ulrike, Dreizler, Andreas, Rottengruber, Hermann

Low Er-Doped Yttrium Gallium Garnet (YGG) as Active Media for Solid-State Lasers at 1651 nm

TBMG-218074/1/2015

The typical approach for producing laser output at the 1651-nm wavelength is via nonlinear frequency conversion. Lasers based on nonlinear conversion are complex, and it is very difficult to provide stability over time and over a wide range of operating temperatures. The efficiency of such optical sources is also low. A much more promising approach is the use of active media that allows for the development of solid-state lasers (SSL) with spectral emission at 1651 nm. An important requirement for this active medium is the ability to support in-band pumping with a low quantum defect since this approach leads to significant improvement in efficiency of SSLs and excellent beam characteristics due to low thermal stress of the active media.

Prediction of Ignition and Combustion Development in an HCCI Engine Fueled by Syngas

2014-32-000211/11/2014

To determine the auto-ignition and combustion mechanisms and the components of syngas that are applicable to homogeneous charge compression ignition (HCCI) engines, the combustion characteristics and the chemical reaction process in an HCCI engine were studied numerically and experimentally using mock syngas with various mixtures of the fuel components. The mock syngas consisted of hydrogen (H2) and carbon monoxide (CO) as the main combustible components, nitrogen (N2) and carbon dioxide (CO2) as incombustible components and a small amount of methane (CH4), assuming the composition of the gas was produced from wood by thermochemical conversion processes. The oxidation reaction process was analyzed numerically using CHEMKIN-PRO. Further experiments were conducted to investigate the validity of the calculated results. Primarily, the effects of hydrogen and carbon monoxide on auto-ignition and combustion were investigated. Auto-ignition timing mainly depends on the in-cylinder gas

Yamasaki, Yudai, Kaneko, Shigehiko

Titan Lake and Shore Sampler

TBMG-20939

11/1/2014

A lake and shore sampling and sample distribution system was developed for a Titan lake environment (93.7 K, in liquid hydrocarbons). The Titan Lake and Shore Sampler (TLASS) would enable the chemical analysis of hydrocarbon lake samples via a Dual Rectilinear Ion and Orbitrap Mass Spectrometer and Nuclear Magnetic Resonance (NMR) Spectrometry.