bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Efficiency Natural Gas Engine Combustion Using Controlled Auto-Ignition
Authors: Hampson Gregory J. 
Published: December 2019

Abstract
Increasingly restrictive limits on Oxides of Nitrogen - NOx levels and desire for low methane emissions from gas engines are driving the change from lean-burn to stoichiometric combustion strategies on heavy-duty on-highway natural gas engines in order to take advantage of inexpensive and effective three-way catalyst technology. The change to stoichiometric combustion has led to increased tendency for engine knock due to higher in-cylinder temperatures. To suppress engine knock, Exhaust Gas Recirculation (EGR) rates from 10 to 30% are used. While high EGR rates nominally improve Brake Thermal Efficiency (BTE) and reduce exhaust gas temperatures, they also slow down combustion. However, by deploying a controlled spark triggered homogeneous charge volumetric ignition, very short burn durations can be achieved without the destructive effects of engine knocking towards high efficiency gas engines.
In the interest of achieving 45% BTE in spark ignited an on-highway class 8 truck engines fueled on natural gas and to meet EURO 6 and future California emissions standards of 0.02 gm/kw-hr NOx, Controlled Auto-Ignition (CAI) is herein demonstrated on a 15 liter truck engine. CAI is enabled by (a) having a combustion device capable of exceptionally good combustion stability in the presence of high EGR rates (COV of IMEP &lt; 0.75 %), (b) cylinder pressure based combustion feedback, and (c) fast closed loop combustion control (using a Woodward RT-CDC control system).
This system enables significant reduction in burn duration by controlling a two phase combustion event. The first phase is normal spark ignited propagating flame, which then triggers the second phase which is volumetric auto-ignition. The location and percentage of fuel that burns in the volumetric auto-ignition event is controlled relative to that which occurs via the conventional spark ignited flame propagation process by use of high speed combustion in the loop feedback control. Auto-ignition mass fraction burned (MFB) ratios of 25–50% have been achieved yielding higher heat release rates at the end of combustion than at the center of combustion with the result being a shortening of the combustion burn duration from a nominal 20–30 degrees to a near optimal 10–15 degrees even with EGR rates as high as 25%. A novel and patent pending burn duration control strategy is employed to stably maintain this knock-free combustion strategy even with compression ratio as high as 14:1. The benefits are significant increase in Brake Thermal Efficiency and substantial reduction in engine out methane emissions without sacrifice of transient responsiveness.
Assessing the Performance of Advanced Cooling Techniques on Thermal Management of Next-Generation Power Electronics
Authors: Acharya Palash V. , Bahadur Vaibhav , Hebner Robert , Ouroua Abdelhamid , Strank Shannon 
Published: December 2019

Abstract
Rapid miniaturization alongwith increasing heat loads in power electronics devices like insulated-gate bipolar transistors (IGBTs) have necessitated the need for advanced thermal management technologies in the packaging of these devices. This study quantifies the benefits of key advanced thermal management solutions for packaging of power electronics packages. Thermal resistance network modeling is used to estimate the maximum heat flux that can be dissipated by an IGBT package, while maintaining the junction temperature below 125 °C and 200 °C for silicon and silicon carbide (wide bandgap material) devices, respectively. While the model is completely analytical, it does address important complexities associated with heat flow in packages via the use of a sub-model to account for thermal spreading. The advanced cooling technologies evaluated in this study include the use of high thermal conductivity polymer heat sinks, double-sided heat sinking of packages, liquid cooling (single and two-phase), jet impingement and spray cooling. Additionally, combinations of these cooling technologies are evaluated as well. The heat dissipation achievable from these technologies is compared with that from an air cooled copper heat sink (baseline). The results of this study provide insights and a starting point for selecting thermal management technologies (or combinations) based on the heat dissipation requirements of power electronics packages.
Effect of Inclined Angle of Radiator on Natural Convective Heat Dissipation Performance
Authors: Ma Tengfei , Wang Wen 
Published: December 2019

Abstract
The effects of inclined angle on the heat transfer of radiators under natural convection are analyzed with experiment and numerical simulation, there are three radiators with straight fin, oblique fin and pin fin respectively (based on 150 × 150 × 45mm). The numerical simulation could agree with the experiment. The straight fin radiator could provide the best heat dissipation performance under experimental conditions and normal installation angle. The pin fin radiator has the largest heat transfer coefficient, around 7 W/m2·K. The influence of deflection angle is discussed on the heat dissipation capability of the radiator. The heat dissipation of the pin fin radiator is less sensitive to the gravity direction than the straight fin and oblique fin ones.
Automated Method Using Finite Element Analysis to Identify Plated Through Holes and Microvia Stacks at Failure Risk in Complex PCB Designs
Authors: Kalayeh Kourosh M. , Hernandez Natalie , Blattau Nathan , Hillman Craig 
Published: December 2019

Abstract
Since the introduction of plated through holes and microvias into the electronics industry, the reliability and manufacturability of these interconnects have been of great concern to the board designers, specifically in automotive and semiconductor industries. The failure of these structures is one of the main causes of an open circuit in printed circuit boards (PCBs). Typically, single and staggered microvias are not the cause of the failures, therefore, only stacked microvias and plated through holes (PTHs) are considered and analyzed in this study. This study includes broad parametric studies, using the finite element method (FEM), to investigate the effect of different geometrical parameters on the reliability and manufacturability of the stacked microvias and plated through holes. A fully automated methodology is developed to 1) analyze complex PCB designs with thousands of microvias and plated through holes, 2) identify and mark configurations susceptible to failure, and 3) build and run finite element simulations on the marked configurations. In doing so, the PCB drill files are first parsed, and the configurations are binned into three main categories; stacked, staggered and PTH configurations. Then using the related nearest-neighbor algorithms and based on the parametric study results, the configurations prone to failure are identified. Finally, finite element models are generated and simulated under thermal loading for the identified configurations. The simulations results are post processed for both reliability (fatigue life prediction under thermal cyclic loading over PCB service life) and manufacturability (overstress due to thermal shock during solder reflow). The modeling results and predictions correlate well to the experimental results available in the literature.
Double Side System in Package Development Challenge for Heterogeneous Integration
Authors: Kao Feng , Wang Yu-Po , Wang Davidlion , Tsai Jensen , Tsai Mike , Chiu Ryan , He Eric 
Published: December 2019

Abstract
With consumer functionality increasing, more and more active die and passive component integrated into one packaging. Next 5G product design trend is requiring small form factor and better thermal dissipation, original single side product is no larger on optimized solution with larger package size, expensive coreless substrate structure stacked via, in order to accommodate product electrical and characteristic requirement. Considering market driving force toward high performance and lower package cost, double side system in package (SiP) structure is able to realize and fulfill form factor and product characteristic requirement.
On this paper, double side SiP package platform will use dual side Surface Mount Technology (SMT) technology and double side molding structure to form outline and also shrink the overall package size. The calculation of package thermal performance can be enhance around 30% and package size can be shrunk around 40% area, compared to single side SiP which package area could be reduced from 64 mm2 to 36 mm2. With form factor change, product simulation is becoming important in order to mitigate assembly risk. The package characterization are including warpage and thermal simulation.
Table1: Basic information comparison for traditional SiP & double side SiP PKG
By utilizing advanced package technology and material, such as high speed SMT placement, molding technology, specific copper substrate design and interconnect material integrating into system in package module which provided a unique opportunity to address cost, performance, and time-to-market advantages. The SiP is also a good package platform to consolidate heterogeneous chips. It could be future package trend to accommodate market demand.
The SiP structure has proceed the typical reliability testing results as a verification method. Finally, this paper shows the suitable double side SiP structure which can be adopt in smart phone, IoT and wearable devices product application.
System Electrothermal Transient Analysis of a High Current (40A) Synchronous Step Down Converter
Authors: Murugan Rajen , Chen Jie , Harrison Todd , Kao C. T. , Ai Nathan 
Published: December 2019

Abstract
In this paper, we detailed the system electrothermal transient co-design modeling and silicon validation effort that led to the industry’s first highly efficient, highest power density (40A) synchronous step-down converter. The device was designed in an innovative multichip module (MCM) low-profile LQFN packaging technology. By integrating the control and drive circuitry with two discrete N-channel power MOSFETs, significant reduction in system on-resistance, RDS(ON), was achieved. The validity of the co-design electrothermal modeling methodology was assessed by comparing directly to silicon thermal measurements made on an evaluation module (EVM) which comprises the inductor, capacitor, and other essential components. Correlation between simulation and laboratory measurements on the integrated solution will be discussed.
Investigation Regarding Transient Compact Thermal Model for Microprocessor Packages
Authors: Nishi Koji 
Published: December 2019

Abstract
In recent years, not only static thermal design but also realtime thermal control become important for power efficiency on computing systems. Three-dimensional thermal simulation is widely used to design computing system, however, it takes too long time for intelligent power and thermal management validation because it requires transient thermal simulation with very short time step. To enable rapid simulation environment, compact thermal model which can be employed with both three-dimensional transient thermal simulation and transient thermal network is required. Therefore, this research aims to establish transient state compact thermal model for microprocessor package. This paper briefly introduces steady state compact thermal model for microprocessor, which is proposed as previous work, then, points out key point to extend the model to transient state model. Transient thermal spreading resistance is emulated and the effect is checked by comparing with three-dimensional simulation.
Vandal Glass Heat Distribution and the Effect of Glass Gap Adjustments in Outdoor Digital Display Components
Authors: Kim Jeho , Brown J. Michael , Joshi Yogendra , O’Connor Kevin , Diaz Marcos , Zhang Zhuomin , Yang Peiyan 
Published: December 2019

Abstract
The use of computational fluid dynamics/heat transfer (CFD/HT) software has become common in exploring the thermal and hydrodynamic behavior of many electronic products. Well-designed CFD/HT models are very valuable for driving the product design, but accurate models can be difficult to develop in some cases for a practical use. Manufacturing Resources International (MRI) uses CFD/HT modeling to predict the display limitations of outdoor digital displays under various hazardous environmental conditions. Both the surrounding ambient temperature and solar irradiance are the major contributors to temperature rise inside outdoor digital displays, but most CFD/HT software packages are limited in simulating solar irradiance through semi-transparent materials and multiple surfaces. Therefore, the contribution from solar irradiance must be treated with care when creating a CFD/HT model especially when an optimum number of mesh elements is to be used to minimize the necessary processing power and solution computation time. In the current study, we employ true solar testing to determine how much solar irradiance passes through the vandal glass assembly. In lieu of defining the solar irradiance as a heat flux, a methodology to determine the power that should be imposed on the sun-exposed vandal glass is described. As outdoor digital displays face harsher thermal challenges compared to the displays that are deployed indoors, it is necessary to come up with a display design that can best benefit from the cooling effect. There are numerous parameters that can be adjusted to optimize the display in terms of its thermal performance but in particular, this paper explores the effect of adjusting the gap distance between the vandal glass and the liquid crystal display (LCD) to see how the maximum LCD temperature and fan performance are influenced.
CFD Analysis of Molten Solder Flow Behavior and Bridging Mechanism During Solder Bump Formation
Authors: Miyazawa Risa , Okamoto Keishi , Mori Hiroyuki 
Published: December 2019

Abstract
Technology of fine pitch interconnect with lead-free solder joint has been developed to enhance the performance of flip-chip high density packages. This study presents an investigation of solder bump forming behavior by means of CFD simulation analysis. The flow motion of molten solder is analyzed with 3D model we developed, and the simulation result is validated with the experiment. Moreover, the investigation of factors affecting solder bridging across adjacent pads is also performed. It is revealed that wettability between liquid solder and organic insulator, which is represented as contact angle in the calculation has large effect on the solder bridging phenomena. The simulation result suggests that worsening the wettability of the insulator can reduce the occurrence of bridging.
Experimental Investigation of Single-Phase Cooling in Embedded Microchannels: 3D Manifold Heat Exchanger With R-245fa
Authors: Jung Ki Wook , Lee Hyoungsoon , Kharangate Chirag , Zhou Feng , Asheghi Mehdi , Dede Ercan M. , Goodson Kenneth E. 
Published: December 2019

Abstract
High performance and economically viable thermal cooling solutions must be developed to reduce weight and volume, allowing for a wide-spread utilization of hybrid electric vehicles. The traditional embedded microchannel cooling heat sinks suffer from high pressure drop due to small channel dimensions and long flow paths in 2D-plane. Utilizing direct “embedded cooling” strategy in combination with top access 3D-manifold strategy reduces the pressure drop by nearly an order of magnitude. In addition, it provides more temperature uniformity across large area chips and it is less prone to flow instability in two-phase boiling heat transfer. Here, we present the experimental results for single-phase thermofluidic performance of an embedded silicon microchannel cold-plate bonded to a 3D manifold for heat fluxes up to 300 W/cm2 using single-phase R-245fa. The heat exchanger consists of a 52 mm2 heated area with 25 parallel 75 × 150 μm2 microchannels, where the fluid is distributed by a 3D-manifold with 4 micro-conduits of 700 × 250 μm2. Heat is applied to the silicon heat sink using electrical Joule-heating in a metal serpentine bridge and the heated surface temperature is monitored in real-time by Infra-red (IR) camera and electrical resistance thermometry. The experimental results for maximum and average temperatures of the chip, pressure drop, thermal resistance, average heat transfer coefficient for flow rates of 0.1, 0.2. 0.3 and 0.37 lit/min and heat fluxes from 25 to 300 W/cm2 are reported. The proposed Embedded Microchannels-3D Manifold Cooler, or EMMC, device is capable of removing 300 W/cm2 at maximum temperature 80 °C with pressure drop of less than 30 kPa, where the flow rate, inlet temperature and pressures are 0.37 lit/min, 25 °C and 350 kPa, respectively. The experimental uncertainties of the test results are estimated, and the uncertainties are the highest for heat fluxes &lt; 50 W/cm2 due to difficulty in precisely measuring the fluid temperature at the inlet and outlet of the micro-cooler.
Modeling and Analysis of a Shape Memory Alloy-Based Adaptive Regulator for Thermal Management
Authors: Liang Gary , Sadeghifard Ashkan , Krishna Anirudh , Lee Jaeho , Peraza Hernandez Edwin A. 
Published: December 2019

Abstract
The goal of this work is to develop and model an adaptive thermal management system formed by shape memory alloy (SMA) helical springs and stretchable selective emitters. Emitters are prepared by depositing a metallic layer on an elastomeric film (3M VHB 4910). Strain changes in the film induce alterations of the surface corrugation of the metallic layer, which enables adjustments of its emissivity spectrum. SMAs are materials that undergo moderate recoverable deformations driven by temperature changes. SMA springs are used here as adaptive deformation enablers (both as actuator and thermal sensor). The thermal management system is created by connecting stretchable emitters and SMA springs in series. When the temperature of the system is increased by sunlight irradiation, the SMA springs undergo contractions which elongate the stretchable emitters, flattening their corrugated metallic layer, thereby leading to an increase in their solar reflectivity and allowing radiative cooling. When the system temperature is decreased, the SMA springs relax and allow the emitters to recover their original surface corrugation, leading to an increase in their solar absorptivity and allowing radiative heating. This repeatable process allows the system to exhibit open-loop adaptive regulation of its temperature under varying solar irradiation. A reduced-order model of the system is derived to perform feasibility studies of the concept and results demonstrating the functionality of the system are presented.
Damage of Flexible Electronic Line Printed With Ag Nanoparticle Ink due to High-Current Density
Authors: Saito Daiki , Sasagawa Kazuhiko , Moriwaki Takeshi , Fujisaki Kazuhiro 
Published: December 2019

Abstract
Flexible printed circuits (FPCs) are widely used in electronic devices such as movable part line or wearable sensor. Photolithography is one of the most popular processes for fabricating electric interconnect lines. However, inkjet printing has attracted attention because the method can draw an arbitrary-shape electric lines without any mask. Therefore, nanoparticle metal ink is widely used for printing of conductive electric lines with lowering cost and small-lot production. The physical characteristics such as flexibility or durability of metal nanoparticle ink lines have been evaluated by bending or tensile tests. By contrast, the evaluation method has not been sufficiently established for the electrical characteristics of these lines, and the failure mechanism under high-current density has not been clarified. According to scaling down of electric devices, current density and Joule heating in device lines increase and electromigration (EM) damage becomes a serious problem. EM is a transportation phenomenon of metallic atoms caused by electron wind under high-current density. Reducing EM damage is extremely important to enhance device reliability. In this study, current loading tests of metal nanoparticle ink line were performed to discuss damage mechanism and evaluate electrical reliability under high-current density condition.
As the results of current loading tests, the thickness of cathode part of straight-test line was decreased. It is considered that atomic transport from the cathode to the anode occurred by EM phenomenon. The line surface became rough and aggregates of particles generated at middle or anode parts of straight-test line by high-current loading. Both of atomic transport and aggregate generation were closely related the changes of potential drop, their dominances were varied depending the current density value.
Evaluation of Thermal and Electrical Properties of Nano-Enhanced PCM for Usage in High-Voltage Systems
Authors: Iradukunda Ange-Christian , Kasitz Josh , Moreno Fernando , Huitink David 
Published: December 2019

Abstract
Rapid temperature transients sustained during operation of high voltage electronics can be difficult to manage by relying solely on uniform heat removal mechanisms. Phase Change Materials (PCMs) can be useful as a buffer against these intermittent temperature spikes when integrated into electronic packages. However, their integration poses challenges of both physical and electrical interactions within the package, particularly in high voltage systems. The present study aims to evaluate electrical and thermal properties of nano-enhanced PCMs to inform integration in high voltage systems. The nanocomposites are obtained by seeding 0.0006–0.12 wt% of Gold, Graphene Oxide, and Iron Oxide particles to Sorbitol. Improvements in thermal properties including latent heat as high as 15% are observed; however, this comes at the expense of dielectric strength of the PCM.
Stator Diagnosis in Permanent Magnet Synchronous Motor (PMSM)
Authors: Zholbaryssov Madi , Sarwar Azeem 
Published: December 2019

Abstract
GM has a vision of future with zero crashes, zero emissions, and zero congestion. Permanent Magnet Synchronous Motors will be integral part of an all-electric future, due to their excellent power to mass ratio and smaller size, which promises to deliver the zero emission world. Making sure that these motors do not fail abruptly without warning, will also reduce congestion caused on the roads by such incidents. Stator winding health monitoring presented in this article allows to detect a fault at its early stage, which greatly increases the chances of the customer being able to repair electric drive system before it completely fails. We present approach for detecting shorted turn faults in stator winding of permanent magnet synchronous motor. The approach is based on monitoring negative sequence admittance for certain operating conditions. Timely fault detection also allows to take preventive action to limit damage propagation across the electric drive, thus, reducing repair and warranty costs. The research presented in this article also furthers GM’s strategic initiative to develop Vehicle Health Management (VHM) technologies that positively impact customer ownership experiences and drive their long-term loyalty to GM brands.