bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Experimental Investigation on the Combustion and Emissions Performance of a Natural Gas–Diesel Dual Fuel Engine at Low and Medium Loads
Authors: Guo Hongsheng , Neill W. Stuart , Liko Brian 
Published: January 2016

Natural gas is an abundant and inexpensive fuel in North America. It produces lower greenhouse gas emissions than diesel fuel when burned in an internal combustion engine. It is also considered to be a clean fuel because it generates lower particulate matter emissions than diesel fuel during combustion.
In this study, an experimental study was conducted to investigate the combustion and emissions performance of a natural gas – diesel dual fuel engine at low and medium loads. A single cylinder direct injection diesel engine was modified to operate as the dual fuel engine. The diesel fuel was directly injected into the cylinder, while natural gas was injected into the intake port. The operating conditions, such as engine speed, load, intake temperature and pressure, were well controlled during the experiment. The effect of natural gas fraction on energy efficiency, cylinder pressure, exhaust temperature, and combustion stability were recorded and analyzed. The emissions data, including particulate matter, nitric oxides, carbon monoxide, and methane at various natural gas fractions and operating conditions were also analyzed. The results showed that natural gas – diesel dual fuel combustion slightly decreased brake thermal efficiency at low and medium load conditions and significantly reduced carbon dioxide and particulate matter emissions. Methane and NOx emissions increased in dual fuel combustion mode compared to diesel operation. The variation of carbon monoxide emissions in dual fuel mode depended on load and speed conditions.
Engine Capability Prediction for SI Engine Fueled With Syngas
Authors: Xu Hui , LaPointe Leon A. 
Published: January 2016

There are increasing interests in converting solid waste or lignocellulosic biomass into gaseous fuels and using reciprocating internal combustion engine to generate electricity. A widely used technique is gasification. Gasification is a process where the solid fuel and air are introduced to a partial oxidation environment, and generate combustible gaseous called synthesis gas or syngas. Converting solid waste into gaseous fuel can reduce landfill and create income for process owners. However it can be very challenging to use syngas on a gaseous fueled spark ignited engine, such as a natural gas (NG) engine. NG engines are typically developed with pipeline quality natural gas (PQNG). NG engines can operate at lean burn spark ignited (LBSI), or stoichiometric with EGR spark ignited (SESI) conditions. This work discusses the LBSI engine condition.
NG engines can perform very differently when fueled with nonstandard gaseous fuels such as syngas without appropriate tuning. It is necessary to evaluate engine performance in terms of combustion duration, relative knock propensity and NOx emissions for such applications. Due to constraints in time and resources it is often not feasible to test such fuel blends in the laboratory. An analytical method is needed to predict engine performance in a timely manner. This study investigated the possibility of using syngas on a spark ignited engine developed with PQNG. Engine performance was predicted using in house developed models and PQNG as the reference fuel. Laminar flame speed (LFS), adiabatic flame temperature (AFT) and Autoignition interval (AI) are used to predict combustion duration, engine out NOx and engine knock propensity relative to NG at the target Lambda values.
Single cylinder research engine data obtained under lean burn conditions fueled with PQNG was selected as the baseline. LFS, AFT and AI of syngas were computed at reference conditions. Lambda of operation was predicted for syngas to provide the same burn rate as NG at the reference Lambda value for NG. Analysis shows that, using syngas at the selected Lambda, the engine can have less engine out NOx emissions and less knock propensity relative to NG at the same speed and load. Modifications to fuel system components may be required to avoid engine derate.
Capturing Cyclic Variability in EGR Dilute SI Combustion Using Multi-Cycle RANS
Authors: Scarcelli Riccardo , Sevik James , Wallner Thomas , Richards Keith , Pomraning Eric , Senecal Peter K. 
Published: January 2016

Dilute combustion is an effective approach to increase the thermal efficiency of spark-ignition (SI) internal combustion engines (ICEs). However, high dilution levels typically result in large cycle-to-cycle variations (CCV) and poor combustion stability, therefore limiting the efficiency improvement. In order to extend the dilution tolerance of SI engines, advanced ignition systems are the subject of extensive research.
When simulating the effect of the ignition characteristics on CCV, providing a numerical result matching the measured average in-cylinder pressure trace does not deliver useful information regarding combustion stability. Typically Large Eddy Simulations (LES) are performed to simulate cyclic engine variations, since Reynold-Averaged Navier-Stokes (RANS) modeling is expected to deliver an ensemble-averaged result.
In this paper it is shown that, when using RANS, the cyclic perturbations coming from different initial conditions at each cycle are not damped out even after many simulated cycles. As a result, multi-cycle RANS results feature cyclic variability. This allows evaluating the effect of advanced ignition sources on combustion stability but requires validation against the entire cycle-resolved experimental dataset.
A single-cylinder GDI research engine is simulated using RANS and the numerical results for 20 consecutive engine cycles are evaluated for several operating conditions, including stoichiometric as well as EGR dilute operation. The effect of the ignition characteristics on CCV is also evaluated. Results show not only that multi-cycle RANS simulations can capture cyclic variability and deliver similar trends as the experimental data, but more importantly that RANS might be an effective, lower-cost alternative to LES for the evaluation of ignition strategies for combustion systems that operate close to the stability limit.
A Numerical Study of the Benefits of Electrically Assisted Boosting Systems
Authors: Burke Richard 
Published: January 2016

An electric compressor and an electrically assisted turbocharger have been applied to a 2.0L Gasoline and a 2.2L Diesel engine 1D wave dynamic models. A novel approach is presented for evaluating transient response using swept frequency sine wave functions and Fourier Transforms.
The maximum electrical power was limited to 6% of the maximum engine power (12kW and 5kW respectively). The systems were evaluated under steady state and transient conditions. Steady state simulations showed improved Brake Mean Effective Pressure (BMEP) at low engine speeds (below 2500rpm) but electric power demand was lower (3kW vs 8kW) when the electric compressor was on the high pressure side of the turbocharger. This was due to the surge limitation of the turbocharger compressor. The electrically assisted turbocharger offered little opportunity to increase low speed BMEP as it was constrained by compressor map width. Re-matching the turbo could address this but also compromise high engine speeds.
BMEP frequency analysis was conducted in the region of 0.01–2Hz. This was repeated at fixed engine speeds between 1000rpm and 2000rpm. Spectral analysis of the simulated response showed that the non-assisted turbocharger could not follow the target for frequencies above 0.1Hz whereas the electrically-assisted device showed no appreciable drop in performance. When assessing the electric power consumption with the excitation frequency, a linear trend was observed at engine speeds below 1500rpm but more complex behavior was apparent above this speed where BMEP levels are high but exhaust energy was scarce.
Ability of the Methane Number Index of a Fuel to Predict Rapid Combustion in Heavy Duty Dual Fuel Engines for North American Locomotives
Authors: Van Alstine Daniel G. , Montgomery David T. , Callahan Timothy J. , Florea Radu C. 
Published: January 2016

Low natural gas prices have made the fuel an attractive alternative to diesel and other common fuels, particularly in applications that consume large quantities of fuel. The North American rail industry is examining the use of locomotives powered by dual fuel engines to realize savings in fuel costs. These dual fuel engines can substitute a large portion of the diesel fuel with natural gas that is premixed with the intake air. Engine knock in traditional premixed spark-ignited combustion is undesirable but well characterized by the Methane Number index, which quantifies the propensity of a gaseous fuel to autoignite after a period of time at high temperature. Originally developed for spark-ignited engines, the ability of the methane number index to predict a fuel’s “knock” behavior in dual fuel combustion is not as fully understood. The objective of this effort is to evaluate the ability of an existing methane number algorithm to predict rapid combustion in a dual fuel engine.
Sets of specialized natural gas fuel blends that, according to the MWM methane number algorithm, should have similar knock characteristics are tested in a dual fuel engine and induced to experience rapid combustion. Test results and CFD analysis reveal that rapid or aggressive combustion rates happen late in the dual fuel combustion event with this engine hardware configuration. The transition from normal combustion to late rapid combustion is characterized by changes in the heat release rate profiles. In this study, the transition is also represented by a shift in the crank angle location of the combustion’s peak heat release rate. For fuels of similar methane number that should exhibit similar knock behavior, these transitions occur at significantly different relative air-fuel ratios, demonstrating that the existing MWM methane number algorithm, while excellent for spark-ignited engines, does not fully predict the propensity for rapid combustion to occur in a dual fuel engine within the scope of this study. This indicates that physical and chemical phenomena present in rapid or aggressive dual fuel combustion processes may differ from those in knocking spark-ignited combustion. In its current form a methane number algorithm can be used to conservatively rate dual fuel engines. It is possible that derivation of a new reactivity index that better predicts rapid combustion behavior of the gaseous fuel in dual fuel combustion would allow ratings to be less conservative.
RCCI of Synthetic Kerosene With PFI of N-Butanol-Combustion and Emissions Characteristics
Authors: Soloiu Valentin , Muiños Martin , Naes Tyler , Harp Spencer , Jansons Marcis 
Published: January 2016

In this study, the combustion and emissions characteristics of Reactivity Controlled Compression Ignition (RCCI) obtained by direct injection (DI) of S8 and port fuel injection (PFI) of n-butanol were compared with RCCI of ultra-low sulfur diesel #2 (ULSD#2) and PFI of n-butanol at 6 bar indicated mean effective pressure (IMEP) and 1500 rpm. S8 is a synthetic paraffinic kerosene (C6–C18) developed by Syntroleum and is derived from natural gas. S8 is a Fischer-Tropsch fuel that contains a low aromatic percentage (0.5 vol. %) and has a cetane number of 63 versus 47 of ULSD#2. Baselines of DI conventional diesel combustion (CDC), with 100% ULSD#2 and also DI of S8 were conducted. For both RCCI cases, the mass ratio of DI to PFI was set at 1:1. The ignition delay for the ULSD#2 baseline was found to be 10.9 CAD (1.21 ms) and for S8 was shorter at 10.1 CAD (1.12 ms). In RCCI, the premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC from ignition of ULSD#2 or S8, and a second stage, ATDC from n-butanol combustion. RCCI with n-butanol increased the NOx because the n-butanol contains 21% oxygen, while S8 alone produced 30% less NOx emissions when compared to the ULSD#2 baseline. The RCCI reduced soot by 80–90% (more efficient for S8). However, S8 alone showed a considerable increase in soot emissions compared with ULSD#2. The indicated thermal efficiency was the highest for the ULSD#2 and S8 baseline at 44%. The RCCI strategies showed a decrease in indicated thermal efficiency at 40% ULSD#2-RCCI and 42% and for S8-RCCI, respectively.
S8 as a single fuel proved to be a very capable alternative to ULSD#2 in terms of combustion performance nevertheless, exhibited higher soot emissions that have been mitigated with the RCCI strategy without penalty in engine performance.
Application of High Performance Computing for Studying Cyclic Variability in Dilute Internal Combustion Engines
Authors: Finney Charles E. A. , Edwards K. Dean , Stoyanov Miroslav K. , Wagner Robert M. 
Published: January 2016

Combustion instabilities in dilute internal combustion engines are manifest in cyclic variability (CV) in engine performance measures such as integrated heat release or shaft work. Understanding the factors leading to CV is important in model-based control, especially with high dilution where experimental studies have demonstrated that deterministic effects can become more prominent.
Observation of enough consecutive engine cycles for significant statistical analysis is standard in experimental studies but is largely wanting in numerical simulations because of the computational time required to compute hundreds or thousands of consecutive cycles. We have proposed and begun implementation of an alternative approach to allow rapid simulation of long series of engine dynamics based on a low-dimensional mapping of ensembles of single-cycle simulations which map input parameters to output engine performance.
This paper details the use Titan at the Oak Ridge Leadership Computing Facility to investigate CV in a gasoline direct-injected spark-ignited engine with a moderately high rate of dilution achieved through external exhaust gas recirculation. The CONVERGE™ CFD software was used to perform single-cycle simulations with imposed variations of operating parameters and boundary conditions selected according to a sparse grid sampling of the parameter space. Using an uncertainty quantification technique, the sampling scheme is chosen similar to a design of experiments grid but uses algorithms designed to minimize the number of samples required to achieve a desired degree of accuracy. The simulations map input parameters to output metrics of engine performance for a single cycle, and by mapping over a large parameter space, results can be interpolated from within that space. This interpolation scheme forms the basis for a low-dimensional ‘metamodel’ (or model of a model) which can be used to mimic the dynamical behavior of corresponding high-dimensional simulations.
Simulations of high-EGR spark-ignition combustion cycles within a parametric sampling grid were performed and analyzed statistically, and sensitivities of the physical factors leading to high CV are presented. With these results, the prospect of producing low-dimensional metamodels to describe engine dynamics at any point in the parameter space will be discussed. Additionally, modifications to the methodology to account for nondeterministic effects in the numerical solution environment are proposed.
Managing Geohazards in Hard Conditions: Monitoring and Risk Assessment of Pipelines That Crosses Amazonian Jungles and the Andes
Authors: Moya John Erick Malpartida 
Published: January 2016

The hydrocarbon transmission system that belongs to Transportadora de Gas del Perú (TGP), comprise two parallel pipelines: a natural gas (NG) pipeline, which runs from the upstream facilities at Malvinas, in the Amazonian jungle of Cusco-Peru, to a reception station at Lurín (south of Lima); and a natural gas liquid (NGL) pipeline, which transports the condensed liquids from Malvinas to Pisco, on the coast of Peru. The right-of-way (ROW) crosses the Peruvian jungle with both pipelines in its first 200 kilometers, after climbs over the Andes Mountains at an elevation of 4860 masl, and descends steeply toward the coast along the Pacific Ocean.
TGP’s Pipeline Integrity Management System (PIMS) has identified the Weather and Outside Forces such as main threat which increases the risk of the integrity of its pipelines in jungle and mountains areas. In pipelines with particular characteristics such as pipeline which crosses the Andes and the Amazonian jungle, this threat can cause even a greater number of failures than other threats such as Corrosion or TPD. This threat caused the 70% of the leaks of our NGL pipeline. The geotechnical and geologic conditions were key factors in the risk level of the system since the beginning of the operation.
The PIMS of TgP has achieved an important development in the use and suitable handling of the information provided by diverse techniques of pipeline mechanical and the geotechnical inspection and monitoring of the ROW. Different alternative techniques of monitoring have to be taken into account. It is important also to take into account alternative assessment methodologies in order to determine the pipeline exposure, resistance and mitigation to this threat. By integrating these inspections, monitoring and particular assessments as part of PIMS, we have been able get accurate risk assessments in order to mitigate and/or minimize the occurrence of failures. In this way we are able to optimize efforts to preserve the integrity of our system and in addition minimize personal, environmental and business impact.
Risk Assessment is an essential part of the Integrity Management System. Our company developed a very comprehensive and detailed Risk Assessment Model based on the guidelines of API 1160 and ASME B31.8S. The probability model is based on logic trees instead indexing models (the most commonly used), that is because we want to reflect in the result all the variables and factors: Exposition, Resistance and Mitigation Factors.
By means of the pipeline Integrity Management System developed by TGP, we are able to mitigate risks due to outside forces. We have been able to act before any event becomes critical: TGP NGL pipeline’s failure rate due to WOF (number of failures per 1000 kilometers-years) decreases substantially from 5.39 to 1.26 in ten years of operation. For the whole system that rate decreases from 2.33 to 0.46.
Application of the Shape Memory Effect to Restore Smoothness
Authors: Braden Paul , Gainer Kaitlyn 
Published: January 2016

A major worldwide industry is the display and preservation of historical and rare documents, paintings, canvases, tapestries and other works of art. Many private collectors and museums pay large amounts, such as the $23 million for the U.S. National Gallery and $8 million for the U.S. National Archives. There is an even greater demand for many consumers who desire an affordable way to safely maintain their images in top condition for viewing and enjoyment. Another industry where the smoothness of the paper documents is important is in the shipping and delivery business. Here, many shipments are done with cylindrical tubes that cause the paper to appear bent and not flat. In some cases, this can pose a major problem for scanning and electronic devices which need a flat surface for optimal performance. A novel new alternative to traditional conservation methods is the use of Shape Memory Alloys (SMA’s) to remove wrinkles and other surface anomalies.
SMA’s use a thermoelastic property called the Shape Memory Effect (SME) to recover large strains by phase transformation. In this process, the SMA is stretched until the polycrystalline microstructure is detwinned Martensite. Then, energy in the form of heat is applied to the SMA which causes the phase transformation to the more compact Austenite. Thus, a reverse method is the proposed solution for the complex problem faced by art preservation experts. Instead of using large clamps and having to wait for results, we demonstrate how embedded SMA wires in a robust picture frame can provide a continuous restorative force that maintains the picture’s smoothness. Using proper simple wiring from the SMA wires to the picture, it is possible to remove the strains in the paper and hold the picture to the proper smoothness long term. We provide experimental results and offer suggestions for the future use of SMA’s in this new field of art restoration.
Adaptive State Feedback to Maximize the Power Capture and Reduce the Tower Motion of Wind Turbine in Partial Loading Operation
Authors: Thapa Magar Kaman , Balas Mark J. 
Published: January 2016

A direct adaptive control approach is used to track the tip speed ratio of wind turbine to maximize the power captured during the below rated wind speed operation. Assuming a known optimum value of tip speed ratio, the deviation of actual tip speed ratio from the optimum one is mathematically expressed as tip speed ratio tracking error. Since the actual tip speed ratio is not a measurable quantity, this expression for tip speed ratio tracking error is linearized and simplified to express it in terms of wind speed and rotor speed, where rotor speed can easily be measured whereas an estimator is designed to estimate the wind speed.
Important results from stability and convergence analysis of the proposed adaptive controller with state estimation and state feedback is also presented. From the analysis it was observed that the adaptive disturbance tracking controller can be combined with adaptive state feedback to achieve other control objectives such as reducing the wind turbine structural loading. Hence, an adaptive state feedback scheme is also proposed to reduce wind turbine tower fore-aft and side-side motions.
Straight Shape Setting of Nitinol Wires by Using a Laser Beam
Authors: Biffi Carlo Alberto , Coduri Mauro , Casati Riccardo , Tuissi Ausonio 
Published: January 2016

Shape setting is a fundamental step in the production route of Nitinol Shape Memory Alloys (SMAs) for the fixing of the functional properties, such as the shape memory effect and the pseudo-elasticity. The conventional method for making the shape setting needs the use of furnaces.
In this work laser technology was adopted for performing the straight shape setting on commercially available Nitinol thin wires. The laser beam was moved along the wire length for inducing the functional performances. Calorimetric and pseudo-elastic response of the wires, laser annealed, were studied; high energy X-Rays diffraction was done for studying the evolution of the microstructure texture. It can be stated that the laser technology can realize the shape setting of thin SMA wires with pseudo-elastic properties; the wire performances can be modulated in function of the laser power.