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Viewing 1 to 30 of 352
2016-04-05
Technical Paper
2016-01-0295
Sentao Miao, Yan Fu, Margaret Strumolo, Boxiao Chen, Xiuli Chao, Erica Klampfl, Michael Tamor
With increasing evidence for climate change in response to greenhouse gasses (GHG) emitted by human activities, pressure is growing to reduce fuel consumption via increased vehicle efficiency and to replace fossil fuels with renewable fuels. While real-world experience with bio-ethanol, and a growing body of research on many other renewable fuel pathways, provides some guidance as to the cost of renewable transportation fuel, there has been little work comparing that cost to alternative means of achieving equivalent GHG reductions. In earlier work, we developed an optimization model that allowed the transportation and electricity generating sectors to work separately or jointly to achieve GHG reduction targets, and showed that cooperation can significantly reduce the societal cost of GHG reductions.
2016-04-05
Technical Paper
2016-01-0992
Justin Koczak, Andre Boehman, Matthew Brusstar
With increasingly stringent light duty particulate emissions regulations, it is of great interest to better understand the events leading to particulate matter formation. Building a thorough understanding of particulate matter formation is an essential step in developing effective control strategies. It is especially important to do this in such a way as to emulate real driving behaviors, including cold starts and transients. In this study, it was desired to realistically examine the evolution of the particulate emissions during transient operation in a recent model year vehicle equipped with a GDI engine. Three of the major federal test cycles were selected as evaluation schemes: the FTP, the HWFET, and the US06. These cycles capture much of the driving behaviors likely to be observed in typical driving scenarios. Measurements included particle size distributions from a TSI EEPS fast-response particle spectrometer, as well as real-time soot emissions from an AVL MSS soot sensor.
2016-04-05
Technical Paper
2016-01-0951
Jordan Elizabeth Easter, Stanislav V. Bohac
Advanced engine combustion strategies, such as HCCI and SACI, allow gasoline engines to achieve high levels of thermal efficiency with low levels of engine-out NOx emissions due to lean operation, optimal combustion duration and low combustion temperatures. However, even with low engine-out NOx, a modest NOx reduction is necessary to meet current and future emissions regulations. Typically this is handled with a TWC; however, lean operation prevents the TWC catalyst from functioning properly. One potential solution suggested in the research community for handling this challenge without the addition of costly NOx traps or on-board systems for urea injection is the passive TWC-SCR concept. This concept includes the integration of an SCR catalyst downstream of a TWC and the use of periods of rich operation to generate NH3 over the TWC to be stored on the SCR catalyst for use in NOx reduction during lean operation.
2016-04-05
Technical Paper
2016-01-0115
Dev S. Kochhar, Hong Zhao, Paul Watta, Yi Murphey
Intended or unintended lane changes are documented occasions when an accident may occur. Drivers can make improper lane changes when they do not see surrounding traffic (the blind spot problem), or when they may be drowsy or distracted, or impaired by alcohol or drugs. In this paper we present a comprehensive study on predicting the driver’s intent to make a lane change based on continuous monitoring and evaluation of the driver’s physiological measures. The task of an intentional lane change involves several cortical and sub-cortical processes, which, in turn, are reflected in physiological measures. In our previous work we introduced a real-time data acquisition system for acquiring three types of driver physiological measures, namely, the Electrocardiogram (ECG), Respiration signal, and Galvanic Skin Response (GSR). A statistical signal selection algorithm and a neural network trained to predict lane change was also introduced.
2016-04-05
Technical Paper
2016-01-1436
K. Han Kim, Sheila Ebert-Hamilton, Matthew Reed
Automotive seats are commonly described by one-dimensional measurements, including those documented in SAE J2732. However, 1-D measurements provide minimal information on seat shape. A 3-D scanner may provide high-resolution details, but due to inconsistent vertex and polygon compositions, indexing and comparing geometries across different seats are extremely difficult. The goal of this work was to develop a statistical framework to analyze and model the surface shapes of seats by using similar techniques that have been used for modeling human body shapes. The 3-D contour of twelve driver seats of sedans and pickup trucks were scanned and aligned, and 332 landmarks were identified using a semi-automatic process. A template mesh of 18,306 vertices was morphed to match the scan at the landmark positions, and the remaining nodes were automatically adjusted to match the scanned surface. A principal component (PC) analysis was performed on the resulting homologous meshes.
2016-04-05
Technical Paper
2016-01-0501
Jwo Pan, Seung Hoon hong, Frank Yan, Shin-Jang Sung, Aindrea Campbell, Xuming Su
Fatigue behavior of flow drill screw (FDS) joints in lap-shear specimens of aluminum 6082-T6 sheets with and without clearance hole are investigated based on experiments and a structural stress fatigue life estimation model. Lap-shear specimens with FDS joints were tested under quasi-static and cyclic loading conditions. Optical micrographs show that the failure modes of the FDS joints in specimens with and without clearance hole are quite similar under quasi-static and cyclic loading conditions. The fatigue lives of the FDS joints in specimens with clearance hole are longer than those of the FDS joints in specimens without clearance hole for given load ranges under cyclic loading conditions. A structural stress fatigue life estimation model is adopted to estimate the fatigue lives of the FDS joints in lap-shear specimens. The closed from structural stress solution is based on the analytical solution for a plate with a rigid inclusion under a resultant shear load.
2016-04-05
Technical Paper
2016-01-1504
Monica Lynn Haumann Jones, Sheila Ebert-Hamilton, Matthew Reed
Law enforcement officers (LEO) make extensive use of vehicles to perform their jobs, often spending large portions of a shift behind the wheel. Few LEO vehicles are purpose-built; the vast majority are modified civilian vehicles. Data from the field indicate that LEO suffer from relatively high levels musculoskeletal injury that may be due in part to poor accommodation provided by their vehicles. LEO are also exposed to elevated crash injury risk, which may be exacerbated by a compromise in the performance of the occupant restraint systems due to body-borne equipment. A pilot study was conducted to demonstrate the application of three-dimensional anthropometric scanning and measurement technology to address critical concerns related to vehicle design. Detailed posture and belt fit data were gathered from five law enforcement officers as they sat in the patrol vehicles that they regularly used and in a mockup of a mid-sized vehicle.
2016-04-05
Technical Paper
2016-01-0313
Andrej Ivanco, Kan Zhou, Heath Hofmann, Zoran S. Filipi
Recent conflicts have challenged the way how military vehicles are deployed. A wide spread of applications were added on top of the previously known direct engagement between two forces. The design of the military vehicle needs to follow this trend and continuously adapt even under tightening budget. In order to reduce the development cost, time and associated risk, commercial off the shelf products are widely adopted into the design of military vehicles. This paper describes a methodology to design a powerpack unit with a superior efficiency, but by using a standard commercially available engine and a slightly modified generator design. A series hybrid vehicle configuration is selected to demonstrate this methodology and to find a powerpack configuration which meets the power requirements while lowering the fuel consumption. The proposed methodology starts with the FEA analysis of the baseline generator.
2016-04-05
Technical Paper
2016-01-1560
Bo Lin, Chinedum E. Okwudire
Ball nut assemblies (BNAs) are used in a variety of applications, e.g., automotive, aerospace and manufacturing, for converting rotary motion to linear motion (or vice versa). In these application areas, accurate characterization of the dynamics of BNAs using low-order models is very useful for performance simulation and analyses. Existing low-order contact load models of BNAs are inadequate, partly because they only consider the axial deformations of the screw and nut. This paper presents a low-order load distribution model for BNAs which considers the axial, torsional and lateral deformations of the screw and nut. The screw and nut are modeled as finite element beams, while Hertzian Contact Theory is used to model the contact condition between the balls and raceways of the screw and nut. The interactions between the forces and displacements of the screw and nut and those at the ball-raceway contact points are established using transformation matrices.
2016-04-05
Technical Paper
2016-01-0671
Yan Chang, Margaret Wooldridge, Stanislav V. Bohac
Using exhaust gas recirculation (EGR) as a diluent instead of air allows the use a conventional three-way catalyst for effective emissions reduction. Cooled EGR can also reduce fuel consumption and NOx emissions, but too much cool EGR leads to combustion instability and misfire. Negative valve overlap (NVO) is explored in the current work as an alternative method of dilution in which early exhaust valve closing causes combustion products to be retained in the cylinder and recompressed near top dead center, before being mixed with fresh charge during the intake stroke. Because the residuals are recompressed (reheated) during NVO, the strategy enables reaction or reformation of fuel during the NVO period. The effects of recycled burned gases include intake charge heating, dilution (reduction in oxygen concentration), increased heat capacity, chemical reactivity, and stratification.
2016-04-05
Technical Paper
2016-01-0317
Yuanzhan Wang, Jason B. Siegel, Anna G. Stefanopoulou
This paper addresses the scheduling of quantized output power levels (including part load operation and start-up/shutdown periods) for a propane powered solid oxide fuel cell (SOFC) hybridized with a lithium ion battery for tracked mobile robot. The military’s requires silent operation and long duration missions, that cannot be met by batteries alone (low energy density), or with combustion engines (noise). To meet this need we consider an SOFC that can be operated at a few discrete power levels while maintaining its maximum system efficiency. The fuel efficiency is decreased during transients and resulting thermal gradients lead to stress and degradation of the stack; therefore switching power levels should be minimized. Excess generated energy is used to charge the battery, but when it’s fully charged the SOFC should be turned off to conserve fuel.
2016-04-05
Technical Paper
2016-01-0392
HongTae Kang, Abolhassan Khosrovaneh, Xuming Su, Mingchao Guo, Yung-Li Lee, Sai Boorgu, Chonghua Jiang
Joining technology is a key factor to utilize dissimilar materials in vehicle structures. Adaptable insert weld (AIW) technology is developed to join sheet steel (HSLA350) to cast magnesium alloy (AM60). The joint is constructed by combining riveting technology and electrical resistance spot welding technology. This joint technology is applied to construct front shock tower structures composed with HSLA350, AM60, and Al6082. This paper is to develop fatigue life prediction methods for AIW using finite element (FE) techniques. First lap-shear and cross-tension specimens were constructed to characterize the fatigue properties of AIW joint. In FE models of the specimen geometry, the AIW joint was represented with two different methods as area contact method (ACM) and with TIE contact method.
2016-04-05
Technical Paper
2016-01-0627
Kevin Walker, Behzad Samadi, Mike Huang, Jürgen Gerhard, Kenneth Butts, Ilya Kolmanovsky
Model Predictive Control (MPC) design methods are popular amongst automotive control researchers because they explicity address an important challenge faced by today’s control designers: How does one realize the full performance potential of our complex multi-input, multi-output systems while satisfying critical output, state and actuator constraints? Moreover, Nonlinear MPC (NMPC) offers the potential to further improve performance and streamline development for those systems in which the dynamics are strongly nonlinear. These benefits are achieved in the MPC framework by using an on-line model of the controlled system to generate the control sequence that is the solution of a constrained optimization problem over a receding horizon. Motivated by the application of NMPC to the Diesel engine air path control problem, we present a control design environment that leverages Maple’s symbolic computation engine to facilitate NMPC problem formulation, solution, and C-code-generation.
2016-04-05
Technical Paper
2016-01-0726
Jonathan Martin, Chenxi Sun, Andre Boehman, Jacqueline O'Connor
An experimental study was performed to optimize the scheduling of diesel post-injections to reduce soot emissions from a light-duty diesel engine. Post-injections are short, closely-coupled injections of fuel that follow the main injection. Previous work has shown that post-injections can reduce engine-out soot emissions when compared to conventional injection schedules for the same engine load, but only when certain post-injection schedules are used. The purpose of this study is to investigate the impact of post-injection scheduling for a range of engine conditions on a light duty multicylinder turbodiesel engine (1.9L GM ZDTH).
2016-04-05
Technical Paper
2016-01-1090
Kwang Hee Yoo, John Hoard, Andre Boehman, Matthew Gegich
In this study, a model EGR cooler was attached to a 2L GDI engine to study the temporal and spatial development of carbonaceous deposits formed during exhaust flow through the heat exchanger. The engine was not normally equipped with EGR capability, but a high pressure exhaust stream from a tap upstream of the turbocharger was directed to the model EGR cooler to generate deposits. The test section includes the capability to consider surface treatments and various geometries of heat exchanger surfaces. In this paper, we explore the spatial and temporal development of the deposit layer, and relate the deposit formation to operating parameters for the engine (fuel injection timing, engine speed, engine load) and operating parameters for the EGR cooler (exhaust flow rate, coolant temperature, heat exchanger geometry). Deposit mass accumulation is tracked during the experiment, and deposit morphology is explored via scanning electron microscopy.
2016-04-05
Technical Paper
2016-01-1035
Rasoul Salehi, Jason Martz, Anna Stefanopoulou, Taylor Hansen, Andrew Haughton
Supercharging an already turbocharged heavy duty diesel engine can extend the smoke limits and allow aggressive downspeeding for higher fuel economy. Analysis of relevant heavy duty drive cycles points to several demanding torque transients that become the prototypical tip-ins where the supercharger integration with a 13 L Diesel engine are analyzed. Supercharger integration can have two forms; a low-pressure (LP) one where the supercharger is placed upstream of the turbocharger compressor and high-pressure (HP) one where the supercharger is inserted downstream of the turbocharger compressor. Parameters such as the supercharger size and type, supercharger bypass valve response and intercooler performance influence the best location for integrating the supercharger into the engine. In addition, different thermodynamic conditions (i.e. pressure and temperature) imply different requirements of strength and durability for each configuration.
2016-04-05
Technical Paper
2016-01-0307
Weiran Jiang, Alyssa Bennett, Nickolas Vlahopoulos, Matthew Castanier, Ravi Thyagarajan
Assessing the dynamic performance of multilayer panels subjected to impulsive loading is of interest for identifying configurations that either absorb energy or transmit the energy in the lateral directions. A reduced-order modeling approach is presented in this paper for rapidly evaluating a large number of alternative panel designs. The new approach is based on the reverberation matrix method with the theory of generalized rays for fast analysis of the structural dynamic characteristics of multilayer plates. In the reverberation matrix method, the waves radiated from the dynamic load are reflected and refracted at the interface of two adjacent layers and the waves within the layers are transmitted with a phase lag. These two phenomena are represented by the global scattering matrix and the global phase matrix, respectively. The product of these two matrices after some mathematical manipulations provides a reverberation matrix that represents the waves within the entire plate.
2016-04-05
Technical Paper
2016-01-0186
Hyunki Sul, Taehoon Han, Mitchell Bieniek, John Hoard, Chih-Kuang Kuan, Daniel Styles
Exhaust gas recirculation (EGR) cooler usage in diesel engine has a great effect on lowering NOx production. Engine coolant cools down the temperature of exhaust gas recirculated to the engine, and significantly reduces the engine out NOx by lowering peak in-cylinder temperature. An ongoing concern is that soot and hydrocarbon foul inside the cold surface of the cooler. The fouling layer reduces heat transfer efficiency and increases pressure drop across the cooler. A number of experimental studies have shown that the fouling layer often tends to grow to the certain steady state level and does not develop further. One potential explanation is the removal mechanism derived by the shear stress applied on the soot and hydrocarbon deposit surface. As the deposit layer thickens, applied shear stress on the fouling surface increases. When critical shear stress is applied, deposit particles start to get removed.
2016-04-05
Technical Paper
2016-01-0183
Taehoon Han, Hyunki Sul, John Hoard, Chih-Kuang Kuan, Daniel Styles
Exhaust Gas Recirculation (EGR) coolers are regularly used in diesel engines to reduce the re-circulated gas temperature. A common problem with the EGR cooler is a reduction of the effectiveness due to the inner fouling layer of the tubes caused by thermophoresis, diffusion, hydrocarbon condensation and so on. The effectiveness decreases rapidly at first, and usually asymptotically stabilizes over time. There are various hypotheses of this stabilizing phenomenon; one of the possible theories is a deposit removal mechanism. Verifying such a mechanism and finding out the correlation between this removal mechanism and stabilization tendency would be a key factor to understand the problem. Some authors have proposed that the removal due to blowing velocity, or temperature of the deposit surface are possible influential factors, while other authors suggest removal is not a significant factor.
2016-04-05
Technical Paper
2016-01-0956
Amin Reihani, Benjamin Corson, John W. Hoard, Galen B. Fisher, Evgeny Smirnov, Dirk Roemer, Joseph Theis, Christine Lambert
Lean NOx Traps (LNTs) are one type of lean NOx reduction technology typically used in smaller diesel passenger cars where urea-based Selective Catalytic Reduction (SCR) systems may be difficult to package . However, the performance of lean NOx traps (LNT) at temperatures above 400 C needs to be improved. The use of Rapidly Pulsed Reductants (RPR) is a process in which hydrocarbons are injected in rapid pulses ahead of a LNT in order to expand its operating window to higher temperatures and space velocities. This approach has also been called Di-Air (diesel NOx aftertreatment by adsorbed intermediate reductants) by Toyota. There is a vast parameter space which could be explored to maximize RPR performance and reduce the fuel penalty associated with injecting hydrocarbons. In this study, the mixing uniformity of the injected pulses, the type of reductant, and the concentration of pulsed reductant and oxygen in the main flow were investigated.
2016-04-05
Technical Paper
2016-01-0967
Rohil Daya, John Hoard, Sreedhar Chanda, Maneet Singh
A GT-SUITE vehicle-aftertreatment model has been developed to examine the cold-start emissions reduction capabilities of a Vacuum Insulated Catalytic Converter (VICC). This converter features a thermal management system to maintain the catalyst monolith above its lightoff temperature between trips so that most of a vehicle’s cold-start exhaust emissions are avoided. The VICC thermal management system uses vacuum insulation around the monoliths. To further boost its heat retention capacity, a metal or salt phase-change material (PCM) is packaged between the monoliths and vacuum insulation. To prevent overheating of the converter during periods of long, heavy engine use, a few grams of metal hydride charged with hydrogen are attached to the hot side of the vacuum insulation. The GT-SUITE model successfully incorporated the transient heat transfer effects of the PCM using the effective heat capacity method.
2016-04-05
Technical Paper
2016-01-0424
Mohammed Yusuf Ali, Petr Michlik, Jwo Pan
In this paper, residual stress distributions in rectangular bars due to rolling or burnishing at very high rolling or burnishing loads are investigated by roll burnishing experiments and three-dimensional finite element analyses using ABAQUS. First, roll burnishing experiments on rectangular bars at two roller burnishing loads are presented. The results indicate the higher burnishing load induces lower residual stresses and the higher burnishing load does not improve fatigue lives. Next, in the corresponding finite element analyses, the roller is modeled as rigid and the roller rolls on the flat surface of the bar with a low coefficient of friction. The bar material is modeled as an elastic-plastic strain hardening material with a non-linear kinematic hardening rule for loading and unloading.
2016-04-05
Technical Paper
2016-01-0504
Shin-Jang Sung, Jwo Pan
New analytical stress intensity factor solutions for spot welds in lap-shear specimens under clamped loading conditions are developed based on the beam bending theory to account for the bending moment on the clamped grips and the closed form solutions for rigid inclusions in thin plates under various loading conditions. The analytical solutions for selected ratios of the specimen width to the nugget diameter are compared with the computational solutions based on three-dimensional finite element analyses. Analytical stress intensity factor solutions as functions of the ratio of the specimen width to the nugget diameter for both the pinned connected and clamped loading conditions are compared and presented for future engineering applications. The analytical solutions can include the effects of the weld gap, weld bend, and load offset due to the spacer arrangement at the specimen edges.
2015-09-29
Technical Paper
2015-01-2868
John Woodrooffe, Daniel Blower
Abstract This paper examines truck driver injury and loss of life in truck crashes related to cab crashworthiness. The paper provides analysis of truck driver fatality and injury in crashes to provide a better understanding of how injury occurs and industry initiatives focused on reducing the number of truck occupant fatalities and the severity of injuries. The commercial vehicle focus is on truck-tractors and single unit trucks in the Class 7 and 8 weight range. The analysis used UMTRI's Trucks Involved in Fatal Accidents (TIFA) survey file and NHTSA's General Estimates System (GES) file for categorical analysis and the Large Truck Crash Causation Study (LTCCS) for a supplemental clinical review of cab performance in frontal and rollover crash types. The paper includes analysis of crashes producing truck driver fatalities or injuries, a review of regulatory development and industry safety initiatives including barriers to implementation.
2015-09-15
Journal Article
2015-01-2609
Pinar Acar, Avinkrishnan A. Vijayachandran, Veera Sundararaghavan, Anthony Waas, Mostafa Rassaian
Abstract Minimizing the stress concentrations around cutouts in a plate is often a design problem, especially in the Aerospace industry. A problem of optimizing spatially varying fiber paths in a symmetric, linear orthotropic composite laminate with a cutout, so as to achieve minimum stress concentration under remote unidirectional tensile loading is of interest in this study. A finite element (FE) model is developed to this extent, which constraints the fiber angles while optimizing the fiber paths, proving essential in manufacturing processes. The idea to be presented could be used to derive fiber paths that would drastically reduce the Stress Concentration Factor (SCF) in a symmetric laminate by using spatially varying fibers in place of unidirectional fibers. The model is proposed for a four layer symmetric laminate, and can be easily reproduced for any number of layers.
2015-08-10
Article
Tucked within the University of Michigan's Ann Arbor campus is a glimpse of the automotive future. In this episode of SAE Eye on Engineering, Senior Editor Lindsay Brooke looks at Mcity, a new proving ground that will help automakers and suppliers develop automated and driverless car technologies.
2015-06-15
Technical Paper
2015-01-2237
Nickolas Vlahopoulos, Sergey Medyanik
In the Energy Finite element Analysis (EFEA) method, the governing differential equations are formulated for an energy variable that has been spatially averaged over a wavelength and time averaged over a period. A finite element approach is used for solving the differential equations numerically. Therefore, a library of elements is necessary for modeling the various wave bearing domains that are present in a structural-acoustic system. Discontinuities between wave bearing domains always exist due to the geometry, from a change in material properties, from multiple components being connected together, or from different media interfacing with each other. Therefore, a library of joints is also necessary for modeling the various types of physical connections which can be encountered in a structural-acoustic system.
2015-06-15
Technical Paper
2015-01-2205
John G. Cherng, Simeng Xing, Weiwei Wu, Jan Ladewig, Rolf Balte, Maurice Venegas
Abstract A comprehensive and systematic investigation of the acoustical performance of carbon-nanotube-enhanced polyurethane (PU) foams was performed. The complete foam making process was carried out carefully in order to create stable foams to be integrated with many carbon nanotube materials. A total of eight design parameters were evaluated. Both normal incidence sound transmission loss (STL) and absorption coefficient were measured by use of an impedance tube. It was found that there is an optimum value for most of the design parameters. In general, nanotube-enhanced PU foam definitely demonstrated improvements in both absorption coefficients and sound transmission loss. The improvement of absorption could reach up to 14% and the improvement in STL was quite substantial, i.e. up to 97.5%. This significant improvement in STL with a better absorption coefficient could represent a potential breakthrough in acoustical PU foam manufacturing.
2015-06-15
Technical Paper
2015-01-2306
John G. Cherng, Weiwei Wu, Peiran Ding, Mike Hebbes, Henry Zhang
Abstract This study presents an efficient process to optimize the transmission loss of a vehicle muffler by using both experimental and analytical methods. Two production mufflers were selected for this study. Both mufflers have complex partitions and one of them was filled with absorbent fiberglass. CAD files of the mufflers were established for developing FEA models in ANSYS and another commercial software program (CFEA). FEA models were validated by experimental measurements using a two-source method. After the models were verified, sensitivity studies of design parameters were performed to optimize the transmission loss (TL) of both mufflers. The sensitivity study includes the perforated hole variations, partition variations and absorbent material insertion. The experimental and sensitivity analysis results are included in the paper.
2015-04-14
Technical Paper
2015-01-1710
Xinran Tao, Kan Zhou, Andrej Ivanco, John R. Wagner, Heath Hofmann, Zoran Filipi
Abstract The components in a hybrid electric vehicle (HEV) powertrain include the battery pack, an internal combustion engine, and the electric machines such as motors and possibly a generator. These components generate a considerable amount of heat during driving cycles. A robust thermal management system with advanced controller, designed for temperature tracking, is required for vehicle safety and energy efficiency. In this study, a hybridized mid-size truck for military application is investigated. The paper examines the integration of advanced control algorithms to the cooling system featuring an electric-mechanical compressor, coolant pump and radiator fans. Mathematical models are developed to numerically describe the thermal behavior of these powertrain elements. A series of controllers are designed to effectively manage the battery pack, electric motors, and the internal combustion engine temperatures.
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