bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel ICT-Enabled Collaborative Design Processes and Tools for Developing Non-Road Mobile Machinery
Authors: Åman Rafael , Handroos Heikki , Kärkkäinen Hannu , Jussila Jari , Korkealaakso Pasi
Published: January 2016

The improvement of the energy efficiency is an important topic for non-road mobile machinery developers and manufacturers. These machines normally use fluid power transmission in drivelines and working actuators. New energy efficient technologies, e.g. a hybrid power transmission with an energy recovery feature, have been introduced. Currently most of the manufacturers are still using conventional technologies in their product development process. Human operators have an effect on the overall efficiency of the machines. Taking into account the human effects is difficult and expensive using the conventional design processes and tools.

The objective of this study is to provide international machine manufacturers instrumental, yet novel, community and simulation-based (ICT-enabled) tools/methods for the strategic and cost effective development of their product practices and design processes. The development of models and methods will allow for rapid real-time virtual prototyping of complex machines and machine fleets that operate within a number of worksites or geographical conditions. The introduction of this state-of-the art (and going beyond) advancement in real-time virtual technology, simulation, internet based design technologies and software, cyber-physical and big data processing systems, will present a holistic approach to improve the entire product life. Targeted user groups are manufacturers of non-road mobile machinery (i.e. excavators, wheel loaders, etc.). These machines and production systems share the following key features: 1) They are complex mechatronic systems with several interconnections between hydraulic drives; mechanics, electronics, software and 2) they include autonomous, semiautonomous and human driven operated systems. Methods developed will enable machine manufacturers’ access to technologies that will lead to a more cost effective consumer ordinated, life cycle optimization process.

This paper will introduce the method of developing customized products in a fast, agile and networked way that will lead to significantly reduced life-cycle costs.
Component Analysis for Hydrostatic Transmission for Wave Energy Application: Simulation and Validation
Authors: Dießel Dominic , Bryans Garth , Verdegem Louis , Payne Richard , Murrenhoff Hubertus
Published: January 2016

Marine waves have the potential of playing a significant role in future energy production. Most converter prototypes utilise a hydrostatic transmission or Power-Take Off (PTO) to convert the mechanical motion of an oscillating body to generate electrical power. A test rig has been installed at the Institute for Fluid Power Drives and Controls (IFAS) together with Aquamarine Power and Bosch Rexroth. Currently a new PTO is tested with this test rig. This new PTO is called WavePOD and is intended to become an industry wide standard by providing flexibility to suit a range of different wave energy converters. Accordingly, it is planned that, different to former PTOs proposed, WavePOD is not designed for only one wave energy converter, but can be used with minor adaptions for various types. Thus, it is aimed to achieve economies of scale, decreasing WavePOD’s costs in comparison to other PTOs. Within this paper important components of the hydraulic transmission such as cylinders, check valves, accumulators and pressure relief valves are investigated in terms of their characteristic behaviour during operation. For the various components the simulation model is presented and validated with test results. Thereby the focus is on dynamic behaviour and power losses. The results will enable to monitor the components behaviour during operation without requiring a surplus of sensor data.
Analysis and Mitigation of Valve Switching Losses in Switched Inertance Converters
Authors: Wiens Travis K.
Published: January 2016

Switched inertance converters use digital valves to exploit the inertia of a flow in order to trade flow for pressure or vice versa. These components can be used to efficiently match load and supply pressures, avoiding the energy wasted by using resistive valves. While theoretical switched inertance converters can be highly efficient, practical implementations suffer from a number of energy losses. One of these losses is the valve switching loss: the energy wasted due to the flow experiencing a pressure drop across the partially open valve as the digital valve shifts from one position to the other. This paper quantifies the effect of this loss on the valve’s overall performance. Two novel strategies for mitigating this effect are introduced: a shaped inertance tube design and positioning of the tank-flow valve along the length of the inertance tube.
Crank-Slider Spool Valve for Switch-Mode Circuits
Authors: Yudell Alexander C. , Koktavy Shaun E. , Van de Ven James D.
Published: January 2016

A key component of switch-mode hydraulic circuits is a high-speed two-position three-way valve with a variable duty cycle. This paper presents a new valve architecture that consists of two valve spools that are axially driven by crank-slider mechanisms. By phase shifting the two crank links, which are on a common crankshaft, the duty cycle of the valve is adjusted. The two spools split and re-combine flow such that two switching cycles occur per revolution of the crankshaft. Because the spools move in a near-sinusoidal trajectory, the peak spool velocities are achieved at mid-stroke where the valve land transitions across the ports, resulting in short valve transition times. The spool velocity is lower during the remainder of the cycle, reducing viscous friction losses. A dynamic model is constructed of this new valve operating at 120 Hz switching frequency in a switch-mode circuit. The model is used to illustrate design trade-offs and minimize energy losses in the valve. The resulting design solution transitions to the on-state in 5% of the switching period and the combined leakage and viscous friction in the valve dissipate 1.7% of the total power at a pressure of 34.5MPa and volumetric flow rate of 22.8L/min.
The Impact of Micro-Surface Shaping on the Piston/Cylinder Interface of Swash Plate Type Machines
Authors: Wondergem Ashley M. , Ivantysynova Monika
Published: January 2016

With the wide use of axial piston machines of the swashplate type in industry, it is essential to maximize the overall efficiency of the machines. Focusing on the piston-cylinder interface, as it performs as a hydrodynamic bearing simultaneously fulfilling a sealing function, the overall machine can be improved by reducing the power losses due to viscous friction and leakage flow of this interface. This paper presents a research study in regards to altering the geometry of the piston through micro-surface shaping influencing the generation of the fluid film between the piston and the cylinder. This investigation utilizes a novel fully coupled fluid structure interaction model considering both thermal and elastic deformations of the solid bodies to predict the phenomena occurring within the fluid gap. Encompassed in this simulation study is a diversity of piston micro-surface shapes and a wide range of machine operating conditions. The designs presented include an axial sine wave, a flat, cylindrical design with tapered ends, a barreled shape, a combination of the axial sine wave and barrel, along with a circumferential sine wave. High pressure operating conditions in pumping mode as well as common operating conditions in both pumping and motoring mode are considered for the various designs. The results demonstrate up to a 30% reduction in energy dissipation from a standard piston-cylinder interface at higher pressure operating conditions (over 15% reduction considering all three interfaces of the machine) with the addition of a barrel surface shape while a 25% reduction (over 5% overall) is achievable at lower operating pressures in pumping mode with a waved barrel surface profile. As for motoring mode a 30% reduction (around 10% overall) is possible with the introduction of a waved barrel surface profile on the piston. It will also be shown, that not only are these reductions possible though microsurface shaping of the piston, but the reliability of the machine is also improved by reducing run-in wear all while maintaining a cost-effective, manufacturable design.
An Investigation of Stiffness Modulation Limits in a Pneumatically Actuated Parallel Robot With Actuation Redundancy
Authors: Pitt E. Bryn , Simaan Nabil , Barth Eric J.
Published: January 2016

Actuation redundancy in parallel mechanisms has been predominantly investigated assuming electromechanical actuators. Pneumatic actuation offers new alternatives to achieving stiffness modulation in parallel robots. This paper investigates the limits of stiffness modulation using two alternatives: modulation of joint-level stiffness using antagonistic pneumatic actuators (passive stiffness modulation) and stiffness modulation using antagonistic actuation at the structure level (active stiffness modulation). A surrogate translational parallel robot architecture, which is a variant of the Delta robot with one redundant kinematic chain, is used in this investigation. A simplified model of a pneumatic double-acting piston actuator is used to establish upper and lower bounds for attainable joint-level stiffness. A kinematic model of the parallel robot is presented along with its passive and active stiffness models. A simulation study is carried out assuming attainable joint-level stiffness based on the simplified pneumatic actuator model. The simulations show that, due to the achievable low pneumatic actuator stiffness, the active stiffness contribution can be as high as 65% of the passive stiffness within the robot workspace. This preliminary investigation suggests that pneumatic actuators are uniquely suited for robot interaction tasks (e.g. assembly or rehabilitation) where stiffness control and modulation can offer increased safety and task-specific end-effector stiffness.
LES for Simulating the Gas Exchange Process in a Spark Ignition Engine
Authors: Ameen Muhsin M. , Yang Xiaofeng , Kuo Tang-Wei , Xue Qingluan , Som Sibendu
Published: January 2016

The gas exchange process is known to be a significant source of cyclic variability in Internal Combustion Engines (ICE). Traditionally, Large Eddy Simulations (LES) are expected to capture these cycle-to-cycle variations. This paper reports a numerical effort to establish best practices for capturing cyclic variability with LES tools in a Transparent Combustion Chamber (TCC) spark ignition engine. The main intention is to examine the sensitivity of cycle averaged mean and Root Mean Square (RMS) flow fields and Proper Orthogonal Decomposition (POD) modes to different computational hardware, adaptive mesh refinement (AMR) and LES sub-grid scale (SGS) models, since these aspects have received little attention in the past couple of decades. This study also examines the effect of near-wall resolution on the predicted wall shear stresses. LES is pursued with commercially available CONVERGE code. Two different SGS models are tested, a one-equation eddy viscosity model and dynamic structure model. The results seem to indicate that both mean and RMS fields without any SGS model are not much different than those with LES models, either one-equation eddy viscosity or dynamic structure model. Computational hardware results in subtle quantitative differences, especially in RMS distributions. The influence of AMR on both mean and RMS fields is negligible. The predicted shear stresses near the liner walls is also found to be relatively insensitive to near-wall resolution except in the valve curtain region.
Combustion Characteristics of a 2-Stroke Large Bore Natural Gas Spark-Ignited Engine
Authors: Griffin Aaron A. , Jacobs Timothy J.
Published: January 2016

Naturally, there are complex interactions among internal combustion engine parameters such as in-cylinder pressure, emissions, speed, and load. These basic relationships are studied in a naturally aspirated, spark-ignited, two-stroke large bore natural gas engine. The typical application for such an engine is in the oil and gas industry, operating heavy machinery such as large compressors and oil field pump jacks.

Cylinder pressure measurements averaged over 300 cycles are captured for speeds of 350 and 525 RPM and load ratings of 50%, 75%, and 100% of rated torque at each respective speed. Non-sequential individual cycle pressure curves are also captured to depict cycle-to-cycle variation within the engine at each operating point. Emissions data are captured and presented for each operating point. At another 8 test conditions, pressure measurements averaged from 100 cycles are taken to specifically investigate disagreement among compression pressure curves; these conditions include 350, 400, 440, and 470 RPM at 50% and 85% of the rated load.

It is found that low load cycle-to-cycle variation is extreme, having COV of IMEP values over 30%. Such engines are not designed to operate at low-load conditions. Cyclic variation is shown to decrease with increasing load and decreasing speed. As expected, peak pressures increase with increasing load and decrease with increasing speed. Emissions of THC and CO decrease with increasing load, while emissions of NO are highest at low speed and high load. It is also shown that compression pressure behavior after exhaust port closure but before ignition is different among different speeds and loads. This may be characteristic of scavenging and heat transfer behavior.
Waste Heat Recovery for Locomotive Engines Using the Organic Rankine Cycle
Authors: Jeihouni Yousef , Franke Michael , Lierz Klaus , Tomazic Dean , Heuser Peter
Published: January 2016

Locomotive engines are emitting high levels of exhaust gas emissions and substantial amount of particulates which is thought to have significant global warming potential. In the past years locomotive regulations have been implemented in the United States to control the emission in this application. Also it can be observed that engine emitted carbon dioxides (CO2) will be limited soon for all on-road engine categories to meet the Green House Gases (GHG) norms.

Tier 4 standards apply to locomotives since the beginning of 2015 for newly built or remanufactured engines. NOx and particulate limits have been reduced by around 70% compared to the Tier 3 standards requiring significant advancements in engine technology and / or exhaust aftertreatment solutions. EGR technology is an option to reduce NOx emissions to Tier 4 locomotive standards indeed of its impact on engine fuel consumption as well as the emitted CO2 gas, which may be controlled either by future CO2 or fuel consumption standards.

To cope with this challenge, new engine technology concepts need to be developed. A waste heat recovery system is a beneficial solution to recover the wasted energies from different heat sources in the engine. Especially the considerable amount of exergy in the exhaust gas (EGR and tailpipe), which results from its high temperature and mass flow, has significant recovery potential. By utilizing a waste heat recovery system a portion of this exergy can be converted into a usable form of power, which then will increase the effective power output of the engine system. A major challenge is to recover the wasted exhaust energy with the maximum possible system efficiency. In a Tier 4 locomotive engine, heat from the EGR system as well as the tailpipe waste heat can be recovered by using an Organic Rankine Cycle (ORC) waste heat recovery system.

This paper will discuss the results of a waste heat recovery (ORC) system evaluation for locomotive applications. With the help of thermodynamic calculations the incremental power from ORC system as well as the fuel economy benefit will be evaluated and discussed. Additionally, a reasonable working fluid and the system layout, which are considered for thermodynamic calculations, will be reviewed.
Combustion Trajectory Visualization Model for Study of Conventional and Advanced Direct Injection Combustion Modes
Authors: Bittle Joshua A. , Jacobs Timothy J.
Published: January 2016

Many of the approaches to diagnostics of in-cylinder spatially resolved quantities (such as equivalence ratio, temperature, speciation, etc.) require either optical engines or computational fluid dynamics. These approaches are expensive (time or money) and will likely never be practical for on-board use in the future. The market trend towards real-time control and consumer grade in-cylinder pressure transducers suggest that relatively simple modeling techniques based on cylinder pressure and other standard engine sensors are well situated to be a part of the future engine control schemes. This work expands previous efforts to calculate combustion trajectories (path through equivalence ratio vs. temperature plane) based on cylinder pressure measurements in near real-time.

This work incorporates the current state-of-the-art diesel fuel spray mixing models (Kattke and Musculus entrainment waves) and adds features to accounting for changing cylinder pressure, adaptive time step based on sampling rate of cylinder pressure, and optimizing spray axial resolution for reduced calculation time. Based on the predicted local fuel concentration, flame temperature and relating calculated heat release rates to the amount of fuel burned in each portion of the spray the combustion processes can be tracked to give a cumulative history of the ignition, subsequent mixing and heating/cooling that gives a picture of what combustion looks like on the equivalence ratio vs. temperature plane.

Various engine operating conditions are explored including conventional diesel operation with and without EGR as well as highly dilute late injection low temperature combustion at different injection pressures. The results obtained in this work give encouragement that this type of approach may enable future engine control using these detailed yet computationally simple approaches.
Development of a Stiffness-Based Chemistry Load Balancing Scheme, and Optimization of I/O and Communication, to Enable Massively Parallel High-Fidelity Internal Combustion Engine Simulations
Authors: Kodavasal Janardhan , Harms Kevin , Srivastava Priyesh , Som Sibendu , Quan Shaoping , Richards Keith , García Marta
Published: January 2016

A closed-cycle gasoline compression ignition engine simulation near top dead center (TDC) was used to profile the performance of a parallel commercial engine computational fluid dynamics code, as it was scaled on up to 4096 cores of an IBM Blue Gene/Q supercomputer. The test case has 9 million cells near TDC, with a fixed mesh size of 0.15 mm, and was run on configurations ranging from 128 to 4096 cores. Profiling was done for a small duration of 0.11 crank angle degrees near TDC during ignition. Optimization of input/output performance resulted in a significant speedup in reading restart files, and in an over 100-times speedup in writing restart files and files for post-processing. Improvements to communication resulted in a 1400-times speedup in the mesh load balancing operation during initialization, on 4096 cores. An improved, “stiffness-based” algorithm for load balancing chemical kinetics calculations was developed, which results in an over 3-times faster run-time near ignition on 4096 cores relative to the original load balancing scheme. With this improvement to load balancing, the code achieves over 78% scaling efficiency on 2048 cores, and over 65% scaling efficiency on 4096 cores, relative to 256 cores.
Experimental Analysis of Sudden Pressure Increase Phenomenon by Real-Time Internal Observation of Diesel Particulate Filter
Authors: Fukui Rui , Okamoto Yuki , Nakao Masayuki
Published: January 2016

As a way of reducing the amount of Particulate Matter (PM) contained in the exhaust gas, Diesel Particulate Filter (DPF) is widely used. To keep the condition of DPF normal and effective, estimation of the amount of PM deposits in the DPF is important. The estimation is mainly conducted based on the value of pressure drop across the DPF. Occasionally, the value of the pressure drop rises suddenly and it leads to overestimation of the amount of PM deposits.

In order to elucidate the cause of the sudden pressure drop increase phenomenon, this paper firstly reveals the engine operating conditions which invoke this phenomenon. The authors also have developed a visualization method to realize the wide-perspective internal observation of the DPF. The observation experiment has been conducted with a commercial engine and DPF under the revealed conditions. Experimental results make clear that the phenomenon is caused by PM deposit layer collapse and channel plugging.
Emissions From a Diesel Engine Operating in a Dual-Fuel Mode Using Port-Fuel Injection of Heated Hydrous Ethanol
Authors: Nord Alex J. , Hwang Jeffrey T. , Northrop William F.
Published: January 2016

Aftermarket dual-fuel injection systems in diesel engines using hydrous ethanol have been developed as a means to lower emissions from older diesel-powered equipment. However, our previous work has shown that the emissions benefits of currently available aftermarket intake fumigation injection systems can be inconsistent with manufacturer claims. Our current study evaluates a newly developed aftermarket dual fuel system that incorporates a novel fuel heating system and port fuel injection (PFI). This paper describes an experimental investigation of engine-out emissions from a John Deere 4045HF475 Tier 2 engine with port injection of 180 proof (90% ethanol by volume) hydrous ethanol. The engine was retrofitted with a custom fuel heat exchanger to heat the hydrous ethanol to a range of 46–79°C for helping to improve fuel vaporization in the intake port. PFI duration was controlled using engine speed and throttle position as inputs to achieve a desired fumigant energy fraction (FEF), defined as the amount of energy provided by the hydrous ethanol based on lower heating value (LHV) over the total fuel energy provided to the engine. Data was collected over a range of FEF with direct injected diesel for eight operating modes comparing heated versus unheated hydrous ethanol. Results of the study indicate that as FEF increases, NO emissions decrease, while NO2, CO, THC, and ethanol emissions increase. In addition, it was found that preheating the ethanol using engine coolant prior to injection has little benefit on engine-out emissions. The work shows that the implemented aftermarket dual-fuel PFI system can achieve FEF rates up to 37% at low engine load while yielding modest benefits in emissions.
Numerical Analysis and Experimental Evaluation of Cylinder Liner Macro-Scale Surface Texturing
Authors: Ma Renlian , Mohamad Salaheldin A. , Lu Xiqun , Li Wanyou
Published: January 2016

An experimental and theoretical study is presented to study the effect of surface texturing in the form of circumferential oil grooves on improving the tribological properties of piston ring-cylinder liner tribosystem. Tests were performed on a reciprocating test rig with actual piston rings and cylinder liner segments, and a numerical model has been developed. A comparison was made between the performance of the textured cylinder liners and un-textured cylinder liners. It was found that with the smaller oil groove area density, the reduction in friction force is more obvious, Parabolic and triangular oil grooves are more efficient in friction reducing, and the prediction results by numerical model match the experimental results well in most case.
Factors Determining Anti-Knocking Properties of Gaseous Fuels in Spark Ignition Gas Engines
Authors: Tanaka Hiroki , Kobayashi Kazunobu , Sako Takahiro , Kuwahara Kazunari , Kawanabe Hiroshi , Ishiyama Takuji
Published: January 2016

The factors affecting knock resistance of fuels, including hydrogen (H2), ethane (C2H6), propane (C3H8), normal butane (n-C4H10), and iso-butane (i-C4H10), were determined using modeling and engine operation tests with spark-ignition gas engines. The results of zero-dimensional detailed chemical kinetic computations indicated that H2 had the longest ignition delay time of these gaseous fuels. Thus, H2 possessed the lowest ignitability. Results of engine operation tests indicated that H2 was the fuel most likely to result in knocking. The use of H2 as the fuel produced a temperature profile of the unburned gas compressed by the piston and flame front that was higher than that of the other fuels due to the high specific heat ratio and burning velocity of H2.

The relation between knock resistance and secondary fuel ratio in methane-based fuel blends also was investigated using methane (CH4) as the primary component, and H2, C2H6, C3H8, n-C4H10, or i-C4H10 as the secondary components. When the secondary fuel ratio was small, the CH4/H2 blend possessed the lowest knocking tendency. But as the secondary fuel ratio increased, the CH4/H2 mixture possessed a greater tendency to knock than did CH4/C2H6 due to the high specific heat ratio and burning velocity of H2. These results indicate that the knocking that can occur with gaseous fuels is not only dependent on the ignitability of the fuel, but it also the specific heat ratio and burning velocity.
Rankine Cycle for Hybrid Vehicles: The Potential for CO2 Emissions Reduction
Authors: Kraljevic Ivica , Kollmeier Hans-Peter , Spicher Ulrich
Published: January 2016

This paper presents the analysis of a Rankine cycle unit applied to improve overall efficiency of a hybrid electric vehicle (HEV). Exhaust waste heat is recovered from the internal combustion engine (ICE) and is converted into electrical power that is fed into the electrical system on board. The discontinuously available exhaust waste heat from the ICE operating cycle is stored as sensible heat in a pressurized working fluid applying the principle of a Ruths storage tank. Thus, it can provide almost constant mass flows to the expansion device during discharge in contrast to the standard Rankine cycle. It is also shown that the outlined system configuration leads to faster engine warm up resulting in optimum ICE operating conditions improving fuel economy. The benefits of a mild HEV versus conventional car powertrain are outlined step by step in a vehicle simulation. Additionally, improvement in fuel economy achieved by applying an additional Rankine cycle is demonstrated in the New European Driving Cycle (NEDC).
Modeling of Internal and Near-Nozzle Flow for a GDI Fuel Injector
Authors: Saha Kaushik , Som Sibendu , Battistoni Michele , Li Yanheng , Quan S. , Senecal P. K.
Published: January 2016

A numerical study of two-phase flow inside the nozzle holes and the issuing spray jets for a multi-hole direct injection gasoline injector has been presented in this work. The injector geometry is representative of the Spray G nozzle, an eight-hole counterbore injector, from the Engine Combustion Network (ECN). Simulations have been carried out for a fixed needle lift. Effects of turbulence, compressibility and non-condensable gases have been considered in this work. Standard k–ε turbulence model has been used to model the turbulence. Homogeneous Relaxation Model (HRM) coupled with Volume of Fluid (VOF) approach has been utilized to capture the phase change phenomena inside and outside the injector nozzle. Three different boundary conditions for the outlet domain have been imposed to examine non-flashing and evaporative, non-flashing and non-evaporative and flashing conditions. Noticeable hole-to-hole variations have been observed in terms of mass flow rates for all the holes under all the operating conditions considered in this study. Inside the nozzle holes mild cavitation-like and in the near-nozzle region flash boiling phenomena have been predicted when liquid fuel is subjected to superheated ambiance. Under favorable conditions considerable flashing has been observed in the near-nozzle regions. An enormous volume is occupied by the gasoline vapor, formed by the flash boiling of superheated liquid fuel. Large outlet domain connecting the exits of the holes and the pressure outlet boundary appeared to be necessary leading to substantial computational cost. Volume-averaging instead of mass-averaging is observed to be more effective, especially for finer mesh resolutions.
Large Eddy Simulation of High Reynolds Number Non-Reacting and Reacting JP8 Sprays With a Kerosene Surrogate and Detailed Chemistry
Authors: Bravo Luis , Wijeyakulasuriya Sameera , Pomraning Eric , Senecal P. K. , Kweon Chol Bum
Published: January 2016

High-resolution single-plume JP-8 spray simulations have been performed to characterize detailed mixture formation process of high-pressure sprays for several common rail fuel injectors of interest to the Army. The first phase of the study involves examining the spray-induced turbulent mixing and global penetration parameters to present experimentally validated results across several computationally challenging length scales. Statistical convergence effects on the spray behavior and penetration profiles are presented by conducting several realizations for each injection case study. The second phase of the project adopts the grid-criteria approach developed for evaporating conditions to model turbulent combustion of a JP-8 reacting spray at compression-ignition engine conditions. A coupled Eulerian Lagrangian formulation is used to model the ensuing spray primary and secondary atomization regions using classical Kelvin Helmholtz - Rayleigh Taylor (KH-RT) wave type models. The flow turbulence subgrid scale microstructure is modeled via Dynamic Structure Large Eddy Simulation (DSLES) approach, largely resolving the anisotropic flow structures. The simulations are conducted across several fuel injector nozzle orifice dimensions ranging from 40–147 μm at a rail pressure of 1000 bar and typical compression-ignition engine operating condition of 900K and 60 bar, which is denoted as ECN Spray A. Liquid fuel physical properties are prescribed using a JP-8 surrogate mixture containing 80% n-decane and 20% trimethylbenzene (TMB) by volume.

The reacting gas phase kinetics is modeled using the Aachen mechanism [26–27] and a detailed chemistry approach of a kerosene surrogate mixture. Measurements from the Army Research Laboratory (ARL) Constant Pressure Flow (CPF) chamber provide global spray and combustion parameters for comparison, including spray penetration profiles, ignition delay and flame lift-of-lengths (LOL) for JP-8 fuels. The simulation results present validated non-reacting and reacting spray simulations (ignition delay agreed within 4% and flame LOL agreed within 5% of measured data) and provide insights into the atomization and mixing characteristics across several orifice dimensions.
Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation
Authors: Hanson Reed , Ickes Andrew , Wallner Thomas
Published: January 2016

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13L multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel.

Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study.

The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.
Low Emissions Kit Development for a 1.5MW EMD GP20D Locomotive
Authors: Stoos Christopher R. , Guliaeff Alexander
Published: January 2016

This paper describes the development, testing, and application of a low emissions upgrade kit for 1.5 MW EMD GP20D locomotives. Low emissions development focused on changes to fuel injection timing combined with the application of crank case ventilation system (CCV) and catalyzed diesel particulate filters (DPF). Composed of a porous cordierite ceramic material, the diesel particulate filters are specifically designed for entrapment of diesel particulates while allowing exhaust gases to flow through. Furthermore, the filters are coated with a proprietary catalyzed washcoat that promotes the oxidation of soot within the exhaust gas temperature range observed under normal engine operation. In addition to the low temperature oxidation of soot, the catalyzed filter also reduces carbon monoxide and unburned hydrocarbons.

The test locomotive used for this development, which is owned by CIT Rail, was powered by a recently rebuilt Caterpillar 3516B engine with a rated power of 1.5 MW (2,000 HP). Baseline exhaust emission testing was performed, followed by low emissions retrofit development. In combination with the CCV and new fuel injection calibrations, the DPF system netted significant emissions reductions. The result of the final low emissions upgrade kit was an EPA Tier 1+ certification, with emissions levels that were below EPA Tier 3 locomotive switch cycle standards for oxides of nitrogen (NOx) and below EPA Tier 4 switch cycle standards for hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and smoke.
Effect of Fuel Injection Strategy on DPF Regeneration in Single Cylinder Diesel Engine
Authors: Yoon Sungjun , Kim Hongsuk , Kim Daesik , Park Sungwook
Published: January 2016

Stringent emission regulations (e.g., Euro-6) force automotive manufacturers to equip DPF (diesel particulate filter) on diesel cars. Generally, post injection is used as a method to regenerate DPF. However, it is known that post injection deteriorates specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration becomes one of key technologies for diesel powertrain equipped with a DPF.

This paper presents correlations between fuel injection strategy and exhaust gas temperature for DPF regeneration. Experimental apparatus consists of a single cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, post injection timing covers from 40 deg aTDC to 110 deg aTDC and double post injection was considered. In addition, effects of injection pressures were investigated. The engine load was varied from low-load to mid-load and fuel amount of post injection was increased up to 10mg/stk.

Oil dilution during fuel injection and combustion processes were estimated by diesel loss measured by comparing two global equivalences ratios; one is measured from Lambda sensor installed at exhaust port, the other one is estimated from intake air mass and injected fuel mass. In the present study, the differences in global equivalence ratios were mainly caused from oil dilution during post injection.

The experimental results of the present study suggest an optimal engine operating conditions including fuel injection strategy to get appropriate exhaust gas temperature for DPF regeneration. Experimental results of exhaust gas temperature distributions for various engine operating conditions were summarized.

In addition, it was revealed that amounts of oil dilution were reduced by splitting post injection (i.e., double post injection). Effects of injection pressure on exhaust gas temperature were dependent on combustion phasing and injection strategies.
Bridging the Gap Between Qualitative, Semi-Quantitative and Quantitative Risk Assessment of Pipeline Geohazards: The Role of Engineering Judgment
Authors: Read R. S. Rod , Rizkalla Moness
Published: January 2016

Geohazards are threats of a geological, geotechnical, hydrological or seismic/tectonic nature that can potentially damage pipelines and other infrastructure. Depending on the physiographic setting of a particular pipeline, a broad range of geohazards may be possible along the pipeline route. However, only a limited number of geohazards such as landslides, fault displacement, mining-induced subsidence, liquefaction-induced lateral spreading, and hydrological scour, which can result in permanent ground deformation or exposure of the pipeline to direct impact, typically represent credible threats to pipeline integrity. Identifying potential geohazard occurrences and estimating the likely severity of each occurrence in relation to pipeline integrity is an integral part of geohazard management, and overall risk management of pipelines. Methods for identifying and assessing the potential likelihood and severity of geohazards vary significantly, from purely expert judgment-based approaches relying largely on visual observations of geomorphology to analytically-intense methods incorporating phenomenological or mechanistic models and data from monitoring and field characterization. Each of these methods can be used to assess hazard and risk associated with specific geohazards in terms of qualitative, semi-quantitative, or quantitative expressions as long as uncertainty and assumptions are understood and communicated as part of the assessment. Engineering judgment is highlighted as an essential component to varying degrees of each geohazard assessment approach.
Study for the Determination of Seismic Hazard for the Ocensa Oil Pipeline
Authors: Corrales Julian Javier , García Hugo Alberto , Silva Mauricio Gallego , Avila Elkin Gerardo
Published: January 2016

The Andes mountain range crosses South America from South to North, is created by the subduction of the Nazca plate beneath the South American plate, this situation generates a high seismic and volcanic activity which have been decisive in shaping the relief of the continent. The OCENSA pipeline crosses the Andes Mountains on its way to transport crude from the oil fields of the eastern plains to the port of Coveñas on the Caribbean Sea. Therefore for the integrity department of Ocensa the assessment of seismic hazard is among one of its priorities. In this paper the results of the study in Ocensa for determination of seismic hazard for the pipeline and its major facilities are presented.
A Piezoelectric Based Energy Harvester With Dynamic Magnification
Authors: Castagnetti Davide
Published: January 2016

Energy harvesting from ambient vibrations exploiting piezoelectric materials is an efficient solution for the development of self-sustainable electronic nodes. This work presents a simple and innovative piezoelectric energy harvester, intrinsically including dynamic magnification and inspired by fractal geometry. After an initial design step, computational analysis and experimental validation show a very good frequency response with five eigenfrequencies below 100 Hz. Even if the piezoelectric transducers were put only on a symmetric half of the top surface of the structure, the energy conversion is good for all the eigenfrequencies investigated.
Study of Periodic Domain Patterns in Tetragonal Ferroelectrics Using Phase-Field Methods
Authors: Renuka Balakrishna Ananya , Muench Ingo , Huber John E.
Published: January 2016

A sharp-interface model based on the linear constrained theory of laminates identifies eight distinct rank-2 periodic patterns in tetragonal ferroelectrics. While some of the periodic solutions, such as the herringbone and stripe patterns are commonly observed, others such as the checkerboard pattern consisting of repeating polarization vortices are rarely seen in experiments. The linear constrained theory predicts compatible domain arrangements, but neglects gradient effects at domain walls and misfit stresses due to junctions of domains. Here, we employ a phase-field model to test the stability of the periodic domain patterns with in-plane polarizations, under periodic boundary conditions which impose zero average stress and electric field. The results indicate that domain patterns containing strong disclinations are of high energy and typically unstable in the absence of external stresses or electric fields. The study also provides insight into the internal stresses developed in the various domain patterns.
Robust Sensing and Reversible Actuation Using Triblock Copolymer Stabilized Intradroplet Interfaces
Authors: Tamaddoni Nima , Taylor Graham J. , Sarles Stephen A.
Published: January 2016

In this work, a recently developed method for forming copolymer-stabilized interfaces (CSI) between aqueous droplets is pursued to as a means to construct smart materials and systems. The ABA type copolymer employed consists of two hydrophilic (PEO) groups sandwiching a hydrophobic PDMS core. Aqueous droplets submerged in triblock copolymer (PEO-PDMS-PEO)-oil mixtures are rapidly coated in copolymer monolayers, however, unlike phospholipid-stabilized droplet interface bilayers (DIBs), electrical measurements reveal that there is no spontaneous formation of a “thinned” interface with droplet contact alone. The capacitance of the interface begins increasing significantly only upon application of sufficient voltage (>100mV), and capacitance then stabilizes within minutes. Further, the interfacial capacitance and area decreases when applied voltage is reduced back to 0mV, and droplets eventually return to their initial separated state. The fact that droplet adhesion and formation of the interface is voltage dependent and completely reversible clearly distinguishes a CSI from a DIB, and the novel polymer based interface is significantly more robust with average rupture potential of ≥ 800mV compared to 200–300mV with DIBs.

Durable and stable CSIs could feasibly be used in applications ranging from sensing and energy harvesting to mechanical actuation. To demonstrate, this work introduces a new version of the DIB based hair cell sensor, now replacing lipids with block copolymers to provide greater durability, stability, and resistance to rupture when subjected to airflow. We calculate the current generated by the vibrating membranes in DIBs and CSIs to study the influence of surfactant selection on the hair cell durability and the related airflow operation range. We conclude that the hair cell constructed using triblock copolymer, as opposed to a DIB, withstands higher nominal airflow speeds (45m/s) and higher applied bias voltages (i.e. 0.1–1V) without rupturing. The ability to apply higher voltages provides a means of tuning the hair-cell sensitivity. Separately, the results of initial trials demonstrate the possibility for voltage-controlled shape change using networks of droplets and CSIs. The ability to apply large voltages and induce change in interfacial area leads to rearrangement of the droplet networks due to conservation of volume. Several embodiments of possible actuators based on this mechanism are discussed. In concert, the various aspects of this work highlight the potential use of CSIs in developing novel, reliable smart materials for sensing and actuation.
Damping Control in a Sandwich Structure With SMP Core
Authors: Butaud Pauline , Ouisse Morvan , Foltête Emmanuel
Published: January 2016

A shape memory polymer (SMP), the tBA/PEGDMA, is elaborated and characterized. The dynamic mechanical characterization of this SMP highlights promising damping properties. The frequency and temperature dependency of the SMP is represented by a viscoelastic model allowing the introduction of the material in the design process of complex structures. A composite sandwich is developed by coupling the SMP with aluminum skins. A finite element model is developed for modeling the behavior of the SMP when integrated in a sandwich structure. The damping performances obtained by the numerical approach are validated experimentally using modal analysis. The experimental results are found to be in good agreement with the predictions of the finite element model. Furthermore, it is found that the controlled heating of the SMP core allows damping the structure over a wide frequency range. The SMP core temperature is tuned from the time-temperature superposition through a calibration curve to correspond to optimal values of damping ratio in the frequency range of interest; a vibration attenuation of about 20dB is observed.
Bench Top Test of a Droop Nose With Compliant Mechanism
Authors: Riemenschneider Johannes , Vasista Srinivas , van de Kamp Bram , Monner Hans Peter
Published: January 2016

Morphing is a technology with high potential to reduce emissions in aviation, since it enables wings to adapt their shape to operate at a higher efficiency over the full range of flight conditions. This paper is presenting a concept to adapt camber by drooping the nose. The scope is the setup and bench top testing of a full scale wing tip leading edge wind tunnel model with a morphing droop nose. The complete model features a span of 1.3 m and a strong taper from the root to the tip. For completeness, the design approach is covered as well. The design comprises a GFRP skin to be drooped by two compliant mechanisms, which are driven by linear motors. The compliant morphing devices are “designed-through-optimization”, with the optimization algorithms including Simplex optimization for composite compliant skin design, continuum-based and load path representation topology optimization methods for compliant internal substructure design. The compliant mechanism is manufactured by nickel-titanium alloy to allow high strains in the order of several percent, which is shown to be critical in the design of such compliant mechanisms. In order to validate the models, strains within the mechanisms are measured while drooping the nose in the bench top test. This is done after installing the mechanisms into the leading edge skin. It can be shown, that the simulation for the inboard mechanism is close to the experimental results. The comparison of strain levels in the skin and in the mechanism during droop reveals that the stiffness distribution between these two components is quite different. As a result this ratio can be taken into account in future design processes in order to distribute strains more evenly. Moreover the 3D shapes of the morphed and clean skin are measured and their comparison with the target shapes is presented as well. Finally, the bench top tests are a proof of concept for the overall concept and design which resultes in a “go” for the following low speed subsonic wind tunnel tests.
Wideband Energy Harvesting by Multiple Piezoelectric Oscillators With an SECE Interface
Authors: Wu P. H. , Shu Y. C.
Published: January 2016

This paper presents the development of wideband energy harvesting by the parallel connection of multiple piezoelectric oscillators attached to a synchronized electric charge extraction (SECE) interface circuit. It is shown that the electric response is determined by the matrix formulation of generalized Ohm’s law. The impedance matrix is explicitly expressed in terms of the equivalent load impedance and system parameters. In addition, the load impedance is found to be independent of external load, so is harvested power. The framework is subsequently validated numerically by SPICE circuit simulations. Finally, the performance evaluation is carried out with comparisons to other interface circuits, including the standard and synchronized switch harvesting on inductor (SSHI) interfaces. The result demonstrates that the bandwidth of an SECE array system is improved and its harvested power is not less than that based on the use of other interface circuits.