bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism for High Velocity Turbulent Jet Combustion From Passive Prechamber Spark Plug
Authors: Chiera Domenico , Riley Mike , Hampson Gregory J.
Published: July 2013

Next generation passive prechamber spark plugs for high BMEP natural gas engines require long ignition delay for durability, fast combustion for efficiency, and low COV for lean engine operation. Additionally, a successful plug should have long life, low cost, and have a robust knock margin, with best-in-class NOx vs. fuel consumption.

This paper discusses the underlying physics of the novel passive prechamber spark plug, the Woodward–Lean Quality Plug (WW-LQP.) The WW-LQP has demonstrated good ignition delay, fast combustion, and low COV at λ > 1.8+, while improving fuel consumption by more than 1% on a lean natural gas engine.

The key operating principles are developed for achieving complete combustion of the prechamber “charge”, leading to high prechamber pressure rise and resulting in high velocity turbulent flame jets, which in-turn provides for fast combustion in the main chamber. The design physics are verified by CFD simulations and on-engine experiments, including pressure measurements in both the prechamber and main combustion chamber.
Investigation of Fuel Spray Propagation, Combustion and Soot Formation/Oxidation in a Single Cylinder Medium Speed Diesel Engine
Authors: Unfug Fridolin , Wagner Uwe , Beck Kai W. , Pfeil Juergen , Waldenmaier Ulf , Celik Oguz , Jaeschke Johannes , Metzger Juergen
Published: July 2013

To fulfil strict emission regulations and the need for higher efficiency of future Diesel engines require an optimized combustion process. Optical investigations represent a powerful tool for getting a better understanding of the ongoing processes. For medium speed Diesel engines, optical investigations are relatively rare or not available. The “Institut für Kolbenmaschinen” (IFKM) and MAN Diesel & Turbo SE performed extensive optical in-situ investigations of the injection and combustion process of a MAN 32/44 CR single cylinder medium speed Diesel engine that provide previously unavailable insights into the ongoing processes. The optical investigations aimed on fuel spray visualization, high-speed soot luminescence measurement and two colour pyrometry applied for five combustion chamber regions.

To apply the optical measurement techniques, two optical accesses were designed. Access no. 1 is placed near the cylinder liner. Access no. 2 is located close to the injector in a 46° angle to the cylinder vertical axis. An insert was used which consists of an illumination port and a visualization endoscope. Additionally some special nozzle designs were used beside the standard nozzle, which have one separated nozzle hole. This enables a simultaneous view from both optical accesses on the same flame cone.

For Mie-Scattering investigation a pulsed Nd:YAG-Laser with 532 nm wavelength was used for illumination and a CCD-camera with an upstream 532 nm optical filter was used for visualization. This combination allows observing the liquid fuel distribution even after start of combustion. Penetration depth of liquid fuel spray was analysed for different swirl numbers, intake manifold pressures, injection timings and injection pressures.

High-speed flame visualization was done by two CMOS cameras which were mounted at two different optical accesses with view on the same flame cone. Due to this application a simultaneous measurement of the flame distribution of two different views was possible. This enables a 3-dimensional investigation of the flame propagation process.

In addition, the advanced two colour pyrometry was applied for five different regions of the same flame cone. Due to a calibration after each measurement the absolute radiant flux can be calculated and thus the absolute temperature and soot concentration. With this procedure it was possible to give a real temperature and soot concentration distribution of the flame cone.

To provide more detailed information about the combustion process, selected engine operation points were simulated with a modified version of the CFD code KIVA3v-Release2 at the IFKM. The simulated results were compared to the measured data.
Understanding Loss Mechanisms and Identifying Areas of Improvement for HCCI Engines Using Detailed Exergy Analysis
Authors: Saxena Samveg , Bedoya Iván Dario , Shah Nihar , Phadke Amol
Published: July 2013

This paper presents a detailed exergy analysis of homogeneous charge compression ignition (HCCI) engines, including a crank-angle resolved breakdown of mixture exergy and exergy destruction. Exergy analysis is applied to a multi-zone HCCI simulation including detailed chemical kinetics. The HCCI simulation is validated against engine experiments for ethanol-fueled operation. The exergy analysis quantifies the relative importance of different loss mechanisms within HCCI engines over a range of engine operating conditions. Specifically, four loss mechanisms are studied for their relative impact on exergy losses, including 1) the irreversible combustion process (16.4–21.5%), 2) physical exergy lost to exhaust gases (12.0–18.7%), 3) heat losses (3.9–17.1%), and 4) chemical exergy lost to incomplete combustion (4.7–37.8%). The trends in each loss mechanism are studied in relation to changes in intake pressure, equivalence ratio, and engine speed as these parameters are directly used to vary engine power output. This exergy analysis methodology is proposed as a tool to inform research and design processes, particularly by identifying the relative importance of each loss mechanism in determining engine operating efficiency.
Study of Diesel Air-Fuel Mixing and Combustion at High Injection Pressures in a Rapid Compression Machine
Authors: Pribicevic I. , Sattelmayer T.
Published: July 2013

Diesel air-fuel mixing and combustion have been investigated in a Rapid Compression Machine (RCM). The measurements were performed at high injection pressures up to 260 MPa and under reacting and non-reacting conditions. The spray was injected through solenoid-controlled multi-hole injectors. Two nozzles were applied with orifice diameters of 175 μm (D175) and 150 μm (D150), respectively. The visualization of the penetration of the liquid and the gaseous phase as well as the spray cone angle under evaporative, non-reacting conditions was carried out by the shadowgraph imaging technique in combination with a high speed camera. For combustion studies the flame luminosity of the flame as well as the chemiluminescence signals emitted by the OH radicals in the UV range were detected.

Investigations revealed different behavior of the macroscopic spray characteristics with the two applied nozzles when increasing the injection pressure from 200 MPa to 260 MPa. With the larger nozzle diameter (D175) the spray penetration and the spray propagation velocity increase as the injection pressure is increased. On the contrary to that, with the smaller nozzle diameter (D150) an increase of the injection pressure had no effect on the spray velocity. With 260 MPa a higher spray penetration was only observed at the beginning of the injection due to the faster opening of the needle. The further propagation of the tip of the spray was similar with 200 MPa and 260 MPa. With both applied nozzles the injection pressure has little effect on the penetration length of the liquid phase. At an applied injection pressure of 200 MPa the near-nozzle spray angle is wider with D175, whereas similar spray angles were observed at 260 MPa. From the measurements in reacting atmosphere an earlier ignition of the fuel and a faster combustion could be shown with nozzle D150. In addition, a higher combustion pressure was measured. This can be attributed to better air-fuel mixing and a higher premixed portion, which was confirmed by the analysis of the spray angles in the far-nozzle region obtained from the shadowgraph images at non-reacting conditions.
Effects of Biodiesel Distillation Process of Waste Cooking Oil Blends on Particle Number and Mass Emissions
Authors: Cordiner S. , Mecocci F. , Mulone V. , Rocco V.
Published: July 2013

The use of biodiesel has been widely accepted as an effective solution to reduce greenhouse emissions. The high potential of biodiesel in terms of PM emission reduction may represent an additional motivation for its wide diffusion. This potential is related to the oxygenated nature of biodiesel, leading to a different PM-NOx trade-off. Wide diffusion is also under debate as it may represent a solution to the highly disputed issue of the development of alternative biofuels sources not competing with the food chain. In fact, besides second generation biofuels (e.g. from algae), the transesterification of Waste Cooking Oil (WCO) is another option, that however needs additional insight. In fact, in this case, the effects on particle emissions are still not well assessed, as well as the impact of fuel distillation on engine performance and emissions.

In this paper an experimental study on particle emissions of a DEUTZ 4L off-road Diesel engine coupled to a DOC-DPF system is proposed. Experimental data have been gathered at the engine test bench of the University of Rome Tor Vergata, by using baseline fossil fuel (B06) and blends (30% vol) with both distilled and non distilled WCO biodiesel. Data have been acquired with respect to the three most probable engine points referring to the NRTC (Non-Road-Transient-Cycle), upstream and downstream of the AfterTreatment System.

Results show that B30 fuels have always lower emission on a mass and number basis, and that distillation process may have an impact especially at high power and torque operation. A slightly better behavior in terms of mass emissions has been observed for the blend with distilled fuel, while a slightly better behavior in terms of particle number has been observed for the blend with non-distilled fuel.
Influence of Post-Injection Parameters on Soot Formation and Oxidation in a Common-Rail-Diesel Engine Using Multi-Color-Pyrometry
Authors: Barro Christophe , Tschanz Frédéric , Obrecht Peter , Boulouchos Konstantinos
Published: July 2013

The emission trade-off between soot and NOx is an issue of major concern in automotive diesel applications. Measures need to be taken both on the engine and on the aftertreatment sides in order to optimize the engine emissions while maintaining the highest possible efficiency. It is known that post injections have a potential for exhaust soot reduction without any significant influence in the NOx emissions. However, an accurate and general rule of how to parameterize a post injection such that it provides a maximum reduction of soot emissions does not exist. Moreover, the underlying mechanisms are not understood in detail.

The experimental investigation presented here provides insight into the fundamental mechanisms of soot formation and reduction due to post injections under different turbulence and reaction kinetic conditions. In parallel to the measurement of soot elementary carbon in the exhaust (using a Photo Acoustic Soot Sensor), the in-cylinder soot formation and oxidation process have been investigated with an Optical Light Probe (OLP). This sensor provides crank angle resolved information about the in-cylinder soot evolution.

The experiments confirm conclusions of earlier works that soot reduction due to a post injection is mainly based on two reasons: increased turbulence (from the post injection) during soot oxidation and lower soot formation due to lower amount of fuel in the main combustion at similar load conditions. A third effect of heat addition during the soot oxidation, which was often mentioned in the literature, could not be confirmed. In addition, the experiments show that variations of turbulence (from swirl) and reaction kinetics have a minor influence on the diffusion controlled heat release rate. However, the time phasing of the soot evolution is highly influenced by these variations with only small changes in the peak soot concentration. It is shown that the soot reduction of a post injection depends on the timing. More precisely, the soot reduction capability of a post injection decreases rapidly as soon as its timing is late in the soot oxidation phase. The soot oxidation rate can only be improved by increased turbulence and heat addition from the post injection in a time window before the in-cylinder soot peak occurs. Depending on EGR and swirl level, a maximum dwell time can be defined after which the post injection effect becomes counterproductive with respect to the soot oxidation rate.
Modified Single-Fluid Cavitation Model for Pure Diesel and Biodiesel Fuels in Direct Injection Fuel Injectors
Authors: Saha Kaushik , Abu-Ramadan Ehab , Li Xianguo
Published: July 2013

A cavitation model has been developed for the internal two-phase flow of diesel and biodiesel fuels in fuel injectors under high injection pressure conditions. The model is based on the conventional single-fluid mixture approach with modification in the phase change rate expressions and local mean effective pressure, considering the effects of viscous stresses and turbulent pressure fluctuations, and also takes into account the effects of turbulence, compressibility and wall roughness. The model is validated by comparing the model predictions of probable cavitation regions, velocity distribution, fuel mass flow rate and pressure with the experimental measurement available in literature. It is found that cavitation inception for biodiesel occurs at a higher injection pressure, compared to diesel, due to its lower saturation pressure. However, supercavitation occurs for both diesel and biodiesel at high injection pressures. RNG k–ε model for turbulence modeling is reliable by comparing its performance with realizable k–ε and SST k–ω models. The effect of liquid phase compressibility becomes considerable for very high injection pressures. Wall roughness is not an important factor for cavitation in fuel injectors.
Simulation and Measurement of the Laser Induced Breakdown in Air and Argon for Nanosecond Order Pulses
Authors: Choi Yongjun , Zhou Chuandong , Stoltz Peter , Joshi Sachin , Yalin Azer
Published: July 2013

The interest in lasers for engine ignition is the possibility of higher efficiency and reduction of pollutants compared with conventional spark plugs. The interest in this area is to understand the laser energy needed for breakdown and ignition in order to better design practical systems. To support such development, the laser induced breakdown of air is simulated by the use of a two-dimensional computational fluid-dynamic model for 10 and 46 ns laser pulses for several pressures and focal spot sizes. The simulation includes the laser propagation, multi-photon ionization, impact ionization, electrons heating and energy loss. The dependence of breakdown irradiance on pulse duration, ambient pressure, and dimensions of the focal region is investigated and compared with experimental results.
Improved Tin Based Bearing Alloy for Low Emission Two-Stroke Engines
Authors: Haedicke Lukas , Mergen Robert , Kari Alexander , Harreither Leopold
Published: July 2013

Recent in Two-stroke engine development for marine applications mainly deal with better and increased overall efficiency hereby reducing the CO2 emissions. Besides a mechanical design change the service conditions play a major role in enhanced efficiency. The so increased engine parameters with higher maximum pressure during combustion will inevitable increase the load on the bearings of the reciprocating parts. Since an increase in the bearing area is not possible due to the engine design parameters the object is to increase the specific load bearing capability of the bearing alloy while keeping the tribological benevolence. In particular, the fatigue properties and the strength of the used tin based alloys, commonly known as whitemetals or babbitts.

This class of alloys stands out due to its emergency running capabilities, embedability and its high flexibility under edge load. Existing Al-based alloys like AlSn40 have improved fatigue properties but they fall behind on the named essential properties. Also, the dimensions of the AlSn40 bearings are limited due to the roll bonding process by which they are produced. On the other hand spin casting as standard production process of Babbitt bearings is limiting the alloying elements due to centrifugal segregation while solidification of the lining alloy. While tin based alloys are used in an environment of 90°C the homologue temperature is 0,7 which means that classic strengthening mechanisms like work-hardening and grain size effects are only shortly employable. Another restricting fact is the requirement of solid solubility for solid solution strengthening which also includes precipitation hardening. Hence there is a limited amount of elements dissolvable and not environmentally hazardous in tin this mechanism is already used to its maximum in the standard babbitts.

In this paper a possible way to circumvent these limits will be presented. The use of high melting elements, compared to Sn, like Co, Ni, Mn, Al and Zn which are partly dissolvable in molten Sn, where used to improve the microstructure and therefor the overall performance of the bearing alloy.

These trace elements serve as grain refinement for the primary precipitation of SbSn and CuSn during solidification. The high melting point of these elements anticipates relaxing processes in the alloy caused by diffusion at the high homologue temperature. Due to the smaller precipitations and the finer structure a better performance can be seen during tests. This leads in a higher strength while maintaining its ductility. Alternate bending tests as well as specific bearing test runs show a significant better fatigue, wear and embedability performance than standard alloys.
Dual-Fuel Diesel Engine Combustion With Hydrogen, Gasoline and Ethanol as Fumigants: Effect of Diesel Injection Timing
Authors: Fang Wei , Huang Bin , Kittelson David B. , Northop William F.
Published: July 2013

Premixed compression ignition (CI) combustion has attracted increasing research effort recently due to its potential to achieve both high thermal efficiency and low emissions. Dual-fuel strategies for enabling premixed CI have been a focus using a low reactivity fumigant and direct diesel injection to control ignition. Alternative fuels like hydrogen and ethanol have been used as fumigants in the past but typically with diesel injection systems that did not allow the same degree of control or mixing enabled by modern common rail systems. In this work we experimentally investigated hydrogen, ethanol and gasoline as fumigants and examined three levels of fumigant energy fraction (FEF) using gasoline over a large direct diesel injection timing range with a single cylinder diesel engine. It was found that the operable diesel injection timing range at constant FEF was dependent on the fumigant’s propensity for autoignition. Peak indicated gross cycle efficiency occurred with advanced diesel injection timing and aligned well with combustion phasing near TDC as we found in an earlier work. The use of hydrogen as a fumigant resulted in very low HC emissions compared with ethanol and gasoline, establishing that they mainly result from incomplete combustion of the fumigated fuel. Hydrogen emissions were independent of diesel injection timing and HC emissions were strongly linked to combustion phasing, giving further indication that squish and crevice flows are responsible for partially burned species from fumigation combustion.
Effect of Anhydrous and Hydrous Ethanol on Performance and Non-Regulated Emissions of an HCCI Engine
Authors: Acevedo Helmer , Tamara Jose , Rodriguez Felipe
Published: July 2013

The automotive sector is currently undergoing drastic changes, driven by the need to simultaneously meet increasingly stringent environmental regulations and achieve more efficient operation over a wide range of engine speeds and loads, while satisfying customer demands in terms of performance, safety, and reliability. In this study an HCCI engine is evaluated for performance and regulated and non-regulated emissions with anhydrous and hydrous ethanol. The Standard EPA Method 8315A was used to determine free carbonyl compounds by derivatization with 2,4-dinitrophenyhydrazine (DNPH). Carbonyls have been measured in emissions using DNPH impregnated cartridges and chemical analyses used high performance liquid chromatography (HPLC). Through the load range achievable, naturally aspirated lean anhydrous ethanol requires high intake temperatures. Although NOx emissions are lower with the use of hydrous ethanol, these emissions are much lower with the use of dry ethanol. The penalty of the use hydrous ethanol is an increase of unburned hydrocarbons and carbon monoxide. Total aldehyde emissions are seen to diminish when an HCCI combustion is carried out with hydrous ethanol. Our analysis gives evidence that HCCI engines can run efficiently on hydrous ethanol fuel and that utilizing hydrous ethanol fuel in HCCI engines improves the energy balance of ethanol production.
Experimental Evaluation of the Effects of Straight Vegetable Oil, and Blends on the Deposits and Wear of the Fuel Injection Equipment
Authors: Agarwal Avinash Kumar , Reddy M. Sarveshwar , Gangwar Jitendra N.
Published: July 2013

Over the last couple of decade, biofuels have shown a lot of promise in terms of relatively higher combustion efficiency and lower emissions vis-à-vis conventional fuels. If mineral diesel is to be replaced by an alternate fuel in existing IC engines, compatibility of the fuel injection equipment (FIE) with these new fuels need to be ascertained because engine performance, combustion and emission characteristics are greatly affected by the FIE. It is reported that FIE components face issues such as injector deposits, injector blockage and pump plunger wear with biofuels. To experimentally investigate the compatibility of FIE with biofuels, a fuel injection simulator was developed to experimentally simulate the engine conditions as closely as possible, outside the engine environment, without the need for combustion of fuel. This simulator was operated for 250 hours with different Karanja oil blends (K100, K20, and K5) and baseline mineral diesel. New fuel pumps and injectors were used for every set of experiment. After every experiment of 250 hours, fuel injector and pumps were dismantled to assess the deposits, wear and surface texture of different components of FIE. Wear was measured by weight loss, dimensional changes and surface texture changes (analyzed by optical microscopy) of the component. For K100, injector blockage was experienced after 185 hours. During inspection, injector nozzle needles using Karanja oil blends showed higher deposits compared to mineral diesel. Dimensional changes of the plunger were highest for K100 compared to mineral diesel. Karanja oil at lower blends provided superior and improved lubricity compared to mineral diesel. In summary, FIE sub-components were damaged to a higher degree with K100, especially pump plunger. Karanja oil blends showed higher deposits on nozzle needle.
An Experimental Study of Normal-Hexadecane and Iso-Dodecane Binary Fuel Blends in a Military Diesel Engine
Authors: Hamilton Leonard J. , Cowart Jim S. , Luning-Prak Dianne , Caton Patrick A.
Published: July 2013

The molecular composition of new hydrotreated renewable fuels consists of both straight chain and branched alkanes. These new fuels do not contain aromatic or cyclo-paraffinic hydro-carbon compounds which are regularly seen in conventional petroleum fuels. Both experimental and modeling work has shown that straight chain alkanes have shorter ignition delays (e.g. higher cetane number) as compared to branched alkanes. In order to better understand the effects of branched and straight chain alkanes fuels in diesel engines, an experimental study was pursued using binary blends of iso-dodecane (iC12H26 with abbreviation: iC12) and normal-hexadecane (nC16H34 with abbreviation nC16) in a military diesel engine (AM General HMMWV ‘Humvee’ engine). Mixtures of 50% iC12 with 50% nC16 as well as 25% iC12 with 75% nC16 were compared to 100% nC16 (cetane) fueled engine operation across the entire speed-load range. Higher nC16 fuel content operation resulted in modestly earlier fuel injection events and combustion phasing that delievered slightly worse engine brake performance (torque and fuel consumption). Interestingly, ignition delay and overall burn durations were relatively insensitive to the binary blends tested. The significantly different physical properties of iC12 relative to nC16 are believed to affect the fuel injection event leading to later fuel injection with increasing iC12 content. Later injection into a hotter chamber mitigates the lower cetane number of the higher iC12 content fuel blends.
Assessing the Effect of E22 Fuel on Two-Stroke and Four-Stroke Snowmobile Performance and Emissions
Authors: Rittenour Michael D. , Weber James C. , Miers Scott A.
Published: July 2013

A limited amount of information exists on the effect of higher ethanol content fuel (greater than 10 vol%) for recreational vehicle engines. The possibility exists for misfueling of these vehicles, as ethanol content may increase at gas stations in the near future. Engine management systems in the recreational vehicle market are typically not equipped with feedback controls to adapt to the increased ethanol content. To address this concern and generate preliminary data related directly to the recreational industry, a study was conducted to evaluate the impact of E22 fuel on steady-state emissions and performance of two production snowmobiles. To fully analyze the impact of higher ethanol blends, cold-start, durability, and material compatibility tests should be performed, in conjunction with emissions and performance tests. While these additional tests were not performed as part of this study, there is a test program that is assessing all these factors on E15 fuel, which will be released in fall 2012. E0 fuel was used to establish baseline performance and emissions data. A 2009 four-stroke snowmobile with a 998cc, liquid-cooled, four-cylinder, intake port-fuel injected engine and a 2009 two-stroke snowmobile with a 599cc, liquid-cooled, two-cylinder, electronically controlled, crankcase-fuel injected engine were used for this study. Neither vehicle had any feedback air-fuel controls or after-treatment devices in the exhaust system. Power, fuel consumption, relevant engine temperatures, as well as, regulated exhaust emissions were recorded using the EPA 5-mode certification test cycle.

The data showed no major impact on power output for either the four-stroke or two-stroke snowmobile. Brake specific fuel consumption varied with E22 as compared to E0. A reduction in CO emissions for both vehicles was observed for the E22 fuel. Both vehicles were factory calibrated rich of stoichiometric and hence, the addition of ethanol to the fuel effectively leaned out the air/fuel ratio and thus reduced the CO emissions. HC emissions were reduced for both the four-stroke and two-stroke engines, though certain test points of the two-stroke engine produced HC emissions that exceeded the analyzer measurement range (idle). Leaner operation reduced HC formation. Exhaust gas temperatures were observed to increase from 20°C – 50°C with E22 fuel, due to enleanment.
Limits for NOx Reduction by EGR in a Heavy Duty Diesel Engine at Stationary and Transient Conditions
Authors: Schalk Erwin , Ofner Herwig , Doppler Christian , Daum Steffen , Danninger Alois , Schutting Eberhard , Kislinger Peter
Published: July 2013

Exhaust gas recirculation (EGR) is an effective engine internal measure to reduce NOx emissions. This is e.g. constituted by the fact that the NOx limit of the current European on-road emission regulation EURO V can be met exclusively by the application of EGR (an overview on emissions regulations is e.g. given in [1]). However, the proposed NOx limits for the upcoming regulations have been lowered significantly which implicates much higher EGR rates compared to the EURO V applications if this strategy is further pursued. This is valid for both the future on-road regulation (EURO VI) and the off-road regulation (Stage IV). In this paper main focus is laid on off-road applications.

One of the main challenges of this task refers to transient engine operation which also requires EGR. Thus, great demands are made to the design and calibration of the charging system in order to guarantee acceptable load response characteristics during the acceleration phases.

An experimental study was carried out with a modified EURO V heavy duty engine which was operated in an engine test cell under stationary and transient conditions with various engine settings. These primarily referred to the EGR rate and smoke limitations during transient operation. In this way the NOx, soot and load response characteristics were systematically investigated. With the used test engine the NOx emissions could not be lowered below a level of approximately 0.6 g/kWh in the Non-Road Transient Test Cycle (NRTC) [1] without a significant deterioration in load response (for comparison — the proposed Stage IV NOx limit is 0.4 g/kWh in the NRTC).
Effect of In-Plane Voiding on the Fracture Behavior of Laser Sintered Polyamide
Authors: Leigh David K. , Bourell David L. , Beaman Joseph J.
Published: July 2013

Laser Sintering, a method of additive manufacturing, is used in the production of concept models, functional prototypes, and end-use production parts. As the technology has transitioned from a product development tool to an accepted production technique, functional qualities have become increasingly important. Tensile properties reported for popular polyamide sintering materials are comparable to the molded properties with the exception of elongation. Reported strains for laser sintered polyamide are in the 15–30% range with 200–400% strains reported for injection molding. The primary contributors to poor mechanical properties in polyamide materials used during Selective Laser Sintering® are studied. Of primary interest are Ultimate Tensile Strength (UTS) and Elongation at Break (EOB) of tensile specimens fabricated under conditions that produce varying degrees of ductile and brittle fracture.
Controlled Porosity of Ceramic Scaffold by Directional Freeze Casting and Scaffold Printing
Authors: Snyder Jessica , Hunger Philipp M. , Wang Chengyang , Wengst Ulrike G. K. , Sun Wei
Published: July 2013

The objective of this work is to produce a 3-dimensional scaffold with hierarchical porosity produced with automated manufacturing control. In this paper we present a two-step manufacturing process: solid freeform fabrication (SFF) of a polymer scaffold, followed by freeze casting, a directional solidification technique, of composite slurry. This combination allows for the production of composite scaffolds with well defined, gradient porosity in two directions. Transverse porosity is created by immersing a printed alginate scaffold in a chitosan (CS)-hydroxyapatite (HA) slurry which is freeze cast to produce a scaffold with highly aligned porosity in the longitudinal direction. The combination of these two processes, printing and freeze casting, provides engineering control over chemical, structural and mechanical cues of the interconnected microenvironment within the scaffolds over several length scales, including features like overall porosity, pore size and shape as well as the choice of material and for example the ratio of polymer to ceramic within the highly porous composite material. Thus, the material’s structure and architecture can be custom-designed by the fabrication processes to regulate diffusion throughout the scaffold as well as to potentially direct cell proliferation and migration.
Robot Learning and Self Optimization of Process Parameters
Authors: Gravel David , Bell Arnold , Zhang Biao , Zhang George
Published: July 2013

Robotic assembly self learning is accomplished through the use of a parameter optimization technique in the midst of running production on a real-world torque converter assembly process. The robotic performance metrics optimized in the manufacturing process are First Time Through (FTT) percentage and cycle time. The data generated is automatically gathered and analyzed by two robot program modules – RAPID motion program module and C# analyzing module. The optimization tool applies Taguchi full factorial Design of Experiments (DOE) that is running on parts during the production process. These results are subjected to automatic statistical analysis to discover the optimal parameter found based on FTT and cycle time performance. The efficacy of this method has been proved in several Ford Motor Company Powertrain assembly plants. The optimization program continues to run iteratively until no further improvement of the process is discovered or an engineering limit set on the parameter range is reached. The test results based on real world data are presented and analyzed in this paper.
A Case Study in 3D Printed Porous Ceramics: Infant Incubator Humidification System
Authors: Diegel Olaf , Withell Andrew , Debeer Deon , Wu Mark
Published: July 2013

This paper describes research in adapting 3D printers to operate with low-cost ceramic materials. The components produced with these clay-based ceramic powders can be fired to produce strong, complex and lightweight ceramic parts. The final material properties, including the porosity of the parts, can be controlled through the part design and, potentially, through additives to the material that burn out during firing. The paper begins with a brief description of the 3D printing process and how it can be used with clay powders. It then introduces a factorial design experiment initiated to explore the effect of ingredient and parameter variations on the dimensional stability and material properties of green and fired ceramic parts. It then presents a case study in which 3D printed ceramic parts are used in the humidification system for an infant incubator for developing countries.
Technologizing and Digitalizing of Medical Professional Skills for a Non-Invasive Ultrasound Theragnostic System
Authors: Koizumi Norihiro , Lee Deukhee , Seo Joonho , Funamoto Takakazu , Sugita Naohiko , Yoshinaka Kiyoshi , Nomiya Akira , Ishikawa Akira , Homma Yukio , Matsumoto Yoichiro , Mitsuishi Mamoru
Published: July 2013

Information and robot technology (IRT) is drawing increasing attention in the technologizing and digitalizing of medical professional skills. In fields such as manufacturing, high-precision tasks, not possible with human, skills have been already realized by industrial robots. The medical field thus expected to advance with progress in the development of medical robots able to provide diagnosis and therapy that are much more precise than those of conventional medical professionals.
Study of Ultrasonic Vibration Laser Metal Deposition Process
Authors: Chen Xueyong , Sparks Todd , Ruan Jianzhong , Liou Frank
Published: July 2013

This paper presents the usage of ultrasonic vibration in laser direct deposition of 316L (stainless steel) powder. Ultrasonic vibration is used to refine the crystalline structure of the deposition. The ultrasonic vibration device vibrates in the laser deposition system along the Z axis while the system is performing metal deposition. A design of experiments approach is applied in studying the effect of vibration on the deposited material. Vibration during deposition led to grain refinement and an increase in micro-hardness. Also, vibration frequency is a significant factor in determining microstructure.
New Trends and Developments in Direct Digital Manufacturing
Authors: Kalla Devi K. , Brown Aaron
Published: July 2013

Direct digital manufacturing (DDM), is advancing rapidly in capability and commercial potential. Directly from CAD data, parts are manufactured without traditional cutting, forming or casting methods. Some of the main developments of the recent past in DDM are discussed in this article. Microstructural and property data will be presented for each type of process, illustrating the benefits and limitations of direct digital manufacturing on various materials, and focusing on emerging and projected applications of metal and ceramic materials by direct digital manufacturing. The review is based on an extensive literature review covering academic publications, company documents and web site information.
MRI-Compatible Grasping Force Sensor With an Inclined Double Parallel Structure Using Fiber Optics
Authors: Arata Jumpei , Terakawa Shogo , Fujimoto Hideo , Sulzer James , Gassert Roger
Published: July 2013

Investigations of human motor control using functional magnetic resonance imaging (fMRI) are increasingly receiving attention, with applications in fields such as motor learning and rehabilitation. In these neuroscience studies, force and position sensors are used to control haptic devices and safely interact with the human motion in an MR environment. However, conventional force sensors such as strain gauges are known to cause electromagnetic interference originating from electrical cables, transducers, and electronics. Light transmission through optical fibers is one alternative that avoids these problems. Since optical fibers do not produce electromagnetic noise, they can be used in an MR environment without electromagnetic interference. In this paper, we propose a novel design of an MRI-compatible grasping force sensor based on these principles. The sensor structure was designed to fit into an MRI scanner with its inclined double parallel mechanism, and was specifically adapted to precision grip tasks. This paper presents the sensor design and preliminary characterization in a non-MR environment.
Photoacoustic Generation Using Gold Nanostructure Fabricated by Femtosecond Laser
Authors: Wu Nan , Tian Ye , Zou Xiaotian , Wang Xingwei
Published: July 2013

Ultrasound generation through photoacoustic principle is a promising method for novel ultrasonic applications. This paper describes a photoacoustic generation method using gold nanostructure fabricated by a femtosecond laser. A nanopattern was fabricated on a quartz substrate. A gold film with a thickness of 50 nm was thermally deposited on the nanoparttern to form a gold nanostructure. The quartz substrate with the gold nanostructure was excited by a nanosecond laser to generate acoustic signals via photoacoustic principle. A quartz substrate coated with a 50 nm thickness gold layer was excited in the same condition for the comparison purpose. Experiment results showed that acoustic signals with amplitudes of 1.56 kPa at a distance of 1.5 mm away from the substrate were generated under the laser energy density of 0.27 mJ/cm2.
Prognostics-Based Replacement and Competition in Service Part Procurement
Authors: Aghdam Faranak Fathi , Liao Haitao
Published: July 2013

Timely maintenance of degrading components is critical to the continuing operation of a system. By implementing prognostics, it is possible for the operator to maintain the system in the right place at the right time. However, the complexity of real-world operating environment makes near-zero downtime difficult to achieve, partly because of a possible shortage of required service parts. To coordinate with a prognostics-based maintenance schedule, it is necessary for the operator to decide when to order the service parts and how to compete with other operators in service part procurement. In this paper, we investigate a situation where two operators are to make prognostics-based replacement decisions and strategically compete for a service part that both operators need at around the same time. A Stackelberg game is formulated in this context. A sequential, constrained maximin space-filling experimental-design approach is developed to facilitate the implementation of backward induction. This approach is efficient in searching the Nash equilibrium when the follower’s best response to the leader’s strategies has no closed-form expression. A numerical study on wind turbine operation is provided to demonstrate the use of the joint decision-making tool in solving such complex, yet realistic maintenance and service part logistic problems.
Design and Validation of Fault Diagnoser Based on Finite State Automaton and Sequential Function Chart for PLC Based Manufacturing System
Authors: Wu Zhenhua , Hsieh Sheng-Jen
Published: July 2013

In ISFA-2010, we proposed a fault diagnoser design based on finite state automaton and sequential function chart to diagnose programmable logic controller (PLC) based manufacturing systems. A deficiency for that paper is that it only laid down a theoretical framework but lacking a detailed implementation and experiment validation. This paper aims at remedying the deficiency with detailed system design to diagnose discrete event system (DES) faults. Systematic diagnosis approach including modeling the plant, mapping output states with sensor readings, and designing diagnoser, was illustrated in this paper. The proposed diagnoser was implemented using Visual Basic to diagnose typical faults a PLC controlled dual robot arm. Experiment validation illustrated that the proposed diagnoser can detect and isolate DES equipment faults with a high fault detection rate of 93%, and detection rate of 80% when including product tolerance fault. The proposed diagnoser can achieve maximum fault detection delay of 9 seconds on the equipment faults. For the future direction, we are planning to extend the proposed diagnoser design to detect probabilistic faults in PLC based automated systems.
Column Generation for Split Pickup and Delivery Vehicle Routing Problem for Crude Oil Transportation
Authors: Izuno Tsukasa , Nishi Tatsushi , Yin Sisi
Published: July 2013

The pickup and delivery crude oil transportation scheduling problem is to find an optimal assignment of requests to a fleet of tankers, sequence of visiting places, and loading and unloading volume of demand simultaneously in order to minimize the total cost with the capacity of the tankers. The problem can be formulated as a split pickup and delivery vehicle routing problem. We apply a column generation algorithm to solve the problem efficiently. In order to obtain a feasible solution by column generation, we propose an effective algorithm to generate a feasible solution satisfying the set partitioning constraints. Computational results demonstrate the effectiveness of the proposed method.
A Research on Flowshop Scheduling Problems With Column Generation
Authors: Tanohata H. , Kaihara T. , Fujii N.
Published: July 2013

Column generation is a method to calculate lowerbound for combinatorial optimization problems, although a feasible schedule is generally obtained with the upperbound. Therefore, in this paper, a new method is proposed to solve the flowshop scheduling problems with column generation, which is composed of the local search and duality gap termination condition. The neighborhood of the local search is composed of columns, and the method is applied in column generation to improve the upperbound and lowerbound. The effectiveness of the proposed method is verified by computational experiments.
Development of an Intelligent Grey-RSS Navigation System for Mobile Robots
Authors: Yao Albert W.-L. , Liao H. T.
Published: July 2013

This study aims at developing an intelligent navigation system for mobile robots to eliminate the cumulative errors caused by using a conventional optical encoder. The optical encoder for mobile robots is supplanted by an intelligent Grey-RSS navigation system (IGRNS) with a RFID system embedded with a RSS (Received Signal Strength) location estimator and a Grey predictor for robot rotation angle prediction. The RFID system identifies the target with active RFID tag. The RSS location estimator then calculates the possible route of robot. The Grey controller optimizes the traveling route quickly. The simulation results show that the proposed IGRNS can reduce robot’s unstable rotation when locating the target. With IGRNS, the mobile robot takes fewer steps to reach target quickly. The performance of IGRNS is better than the one with the RSS navigation system alone.
A Method for Activity Duration Estimation Based on Project Stability
Authors: Morita Daisuke , Suwa Haruhiko
Published: July 2013

During the planning phase in real project management, it is one of essential problems for any project to determine the duration of each activity. This paper proposes a new method for determining the duration of activities of a given project based on a cost associated with the deviation of the starting time of each activity. The proposed method calculates the expected cost associated with a starting time deviation for each activity and then determines the duration of each activity so as to minimize the total expected cost. The proposed method is compared with some conventional methods. The numerical results derive some properties of the estimation methods and demonstrate the effectiveness of the proposed method.
Mobile Robotic Assembly on a Moving Vehicle
Authors: Shi Jane , Hamner Brad , Simmons Reid , Singh Sanjiv
Published: July 2013

Mobile manipulators offer the potential of simultaneous mobility and manipulation to meet the challenges of complex assembly tasks. However, there have been few attempts to utilize mobile manipulators for automating the final assembly of automotive manufacturing process. In this paper, we present the development of control strategies for a mobile manipulator to perform the assembly of automotive wiring harnesses onto a moving vehicle. We highlight the coordinated control framework that incorporates pure pursuit tracking control, discuss constrained motion primitives and reactive visual servo with force constraints, examine contact forces of the wiring harness assembly, and present experimental results for both successful and failed attempts of attaching a wiring harness to a moving vehicle body. Finally, we discuss remaining challenges in achieving robotic assembly automation on moving assembly lines.
3D Model Construction of Cutting Tools and Identification of Workpieces Using Machine Vision for Virtual Machining Simulation
Authors: Nishiyama Mamoru , Sato Ryuta , Shirase Keiichi
Published: July 2013

In virtual machining simulation to verify NC programs for machining operation, construction of 3D (three-dimensional) models of cutting tools to be used and identification of posture and position of workpiece to be machined are quite important to achieve reliable verification.

Especially, a 3D model construction of cutting tools requires skill-full operations and it takes much time and cost. Several geometric parameters to define cutting tool shapes are needed to construct precise 3D models for virtual machining simulation. Even though, careless mistake to set parameters of tool diameter and length causes machining troubles. Therefore, no trouble was happened in virtual machining simulation, it is still required to check machining troubles through the trial-cutting on actual NC machine tools.

In this paper, new methods to construct 3D models of cutting tools and identification of posture and position of workpiece are proposed. Experimental measurement of cutting tool shape is performed on the machine tool using a CCD camera, and a 3D model of cutting tool was constructed successfully. By this method, setting of invalid parameters to define cutting tool shapes can be avoided.

Also, posture and position of the workpiece can be identified successfully. These parameters can be used to detect wrong setup operation before actual machining operation.