Browse Topic: Technical review

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Coaxial Cable Connector Interface - Square Outer ConducterUSCAR19-2 (Current)8/5/2021
This radio frequency (RF) connector interface specification is suited for unsealed automobile applications up to 2 GHz.Dimensional requirements are specified in this document to ensure interchangeability. This RF connector interface specification is intended for in-line, board mount, device mount, straight or angled applications. Performance requirements are specified in SAE/USCAR-2, and in SAE/USCAR-17.
USCAR
REMOVAL TOOLS, CONNECTOR, ELECTRICAL CONTACT, (FORK TYPE, WRAP POST/CRIMP REMOVABLE) TYPE II, CLASS 1, COMPOSITION CAS81969/4A (Current)1/26/2021
AE-8C2 Terminating Devices and Tooling Committee
REMOVAL TOOLS, CONNECTOR, ELECTRICAL CONTACT, (FORK TYPE, WRAPPOST/CRIMP REMOVABLE) TYPE II, CLASS 1, COMPOSITION CAS81969/11A (Current)1/26/2021
AE-8C2 Terminating Devices and Tooling Committee
INSTALLING AND REMOVAL TOOLS, CONNECTOR, ELECTRICAL CONTACT, TYPE I AND II, CLASS 2, COMPOSITION BAS81969/10A (Current)1/26/2021
AE-8C2 Terminating Devices and Tooling Committee
Configuration Management Requirements for Defense ContractsEIA649_1A (Current)8/10/2020
This document applies to hardware and software and provides CM requirements to be placed on contracts after being tailored by the Acquirer. The requirements have been organized by the following five CM functions: a Configuration Planning and Management b Configuration Identification c Configuration Change Management d Configuration Status Accounting e Configuration Verification and Audit
G-33 Configuration Management
Nondestructive Measurement of Residual Strain in Connecting Rods Using Neutrons05-12-03-001810/15/2019
Abstract Increasing the strength of materials is effective in reducing weight and boosting structural part performance, but there are cases where the residual strain generated during the process of manufacturing of high-strength materials results in a decline of durability. It is therefore important to understand how the residual strain in a manufactured component changes due to processing conditions. In the case of a connecting rod, because the strain load on the connecting rod rib sections is high, it is necessary to clearly understand the distribution of strain in the ribs. However, because residual strain is generally measured by using X-ray diffractometers or strain gauges, measurements are limited to the surface layer of the parts. Neutron beams, however, have a higher penetration depth than X-rays, allowing for strain measurement in the bulk material. The research discussed within this article consists of nondestructive residual strain measurements in the interior of connecting rods using the Second Generation Neutron Residual Stress Mapping Facility (NRSF2) at Oak Ridge National Laboratory (ORNL), measuring the Fe (211) diffraction peak position of the ferrite phase. The interior strain distribution of the connecting rod, which was prepared under different manufacturing processes, was revealed. By the visualization of interior strains, clear understandings of differences in various processing conditions were obtained. In addition, it is known that the peak width, which is also obtained during measurement, is suggestive of the size of crystallites in the structure; however, the peak width can additionally be caused by microstresses and material dislocations.
Ikeda, Tomohiro, Jeffery, Bunn R., Fancher, Christopher M., Motani, Ryuta, Matsuda, Hideki, Okayama, Tatsuya
Comparative Analysis between American and European Requirements for Electronic Stability Control (ESC) Focusing on Commercial Vehicles2019-01-21419/15/2019
Analysis of road accidents has shown that an important portion of fatal crashes involving Commercial Vehicles are caused by rollovers. ESC systems in Commercial Vehicles can reduce rollovers, severe understeer or oversteer conditions and minimize occurrences of jackknifing events. Several studies have estimated that this positive effect of ESC on road safety is substantial. In Europe, Electronic Stability Control (ESC) is expected to prevent by far the most fatalities and injuries: about 3,000 fatalities (-14%), and about 50,000 injuries (-6%) per year. In Europe, Electronic Stability Control Systems is mandatory for all vehicles (since Nov. 1st, 2011 for new types of vehicle and Nov. 1st, 2014 for all new vehicles), including Commercial Vehicles, Buses, Trucks and Trailers. On 2015, NHTSA published Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic Stability Control systems for heavy vehicles, requiring Electronic Stability Control (ESC) systems on truck tractors and buses with a gross vehicle weight rating greater than 11,793 kilograms (26,000 pounds) for implementation in 2017. In South America, CONTRAN Resolution 641/2016 establishes mandatory installation of Electronic Stability and Rollover Control in Commercial Vehicles, including Trailers (Jan. 1st, 2022 for new types of vehicle and Jan. 1st, 2024 for all new vehicles). However there isn’t a Brazilian standard to validate the system and its performance shall comply with ECE R13 (Annex 21) or FMVSS 136, as applicable. This paper shows a technical review regarding ESC function, its impact on Commercial Vehicles and clarifies the different systems available for trucks and trailers, considering the differences between stability control systems - full stability and roll-only stability. In addition it will show a comparative analysis between American and European requirements and procedures to validate these vehicles safely.
Iombriller, Silvia Faria, Bolognesi Prado, Wesley, Silva, Marco Andre
Bearing Life Optimization for Automotive Wheel Bearings2019-01-21379/15/2019
Automotive wheel bearings have primary functions of translating the rotating motion of the wheels into linear vehicle motion while bearing the vehicle weight. Bearing life is affected by many parameters such as bearing geometry, vehicle and bearing technical specifications, driving conditions, lubrication conditions, material properties, and so on. In this paper, the optimization of bearing life was performed. Optimization formulation with no constraints was established to solve this problem. The large scale generalized reduced gradient, LSGRG, algorithm was applied to calculate the basic rating life and modified rating life proposed by ISO 281:1990 and ISO 281:2007, respectively. The optimization history for design variables and cost function were investigated. The results showed that the optimized basic rating life and modified rating life increased about 15% and 31% comparing with those of initial life, respectively.
Lee, Seungpyo
Disc Thickness Variation (DTV) Operational Measurement and Influence on the Overall Vehicle Roughness2019-01-21109/15/2019
The brake disc or rotor design is one of the main concerns in the development of the vehicle brake system. One of the key factors of its drawing and manufacture is related with the thermo-mechanical deformation that can transmit further vibrations to the complete vehicle. This phenomenon, called brake judder or roughness, can appear in both cold and hot brake conditions, the latter being especially affected by the thermal factor. The evolution of the disc shape fluctuation and Disc Thickness Variation (DTV) is usually illustrated before and after a test, reflecting typically the same output. However, the real transient disc behavior during these phases is rarely measured and is difficult to determine. The reality is that most of the time, some unexpected deformations may appear, these being the final root cause of the excitation of judder vibration. During the cold judder, the disc starts at a low temperature and controlled DTV, which corresponds to the disc’s natural shape and is only affected by the wear conditions. On the other hand, hot judder is performed by repeating consecutive snubs, heating up the rotors to a high temperature and assessing the roughness in those ranges. In this case, not only the DTV evolution during the stop is important, but also the change between each snub, according to the temperature increase. All in all, the methods presented in this study become a strong tool for understanding how real and operational measurements are done, and how they can be effective for problem solving activities and useful for validating component design developments.
Ferrer, Bernat
Research on Integrated Performance Design for the Braking System2019-01-21209/15/2019
Medium or higher commercial vehicles weight will be increased by 5 to 6 times compared to kerb weight depending on their load carrying capacity. Therefore, a pneumatic braking device is used that produces a greater braking force than hydraulic pressure. Pneumatic braking system is a device that performs mechanical braking using air pressure and shall be designed to an appropriate level, taking into account the multi-physics of air and mechanical phenomena. In addition, the dynamics of the vehicle during braking should be considered due to different vehicle behavior depending on the load carrying capacity. This study utilizes SIL(Software In the Loop) for a comprehensive review of the pneumatic braking performance of vehicles.
Han, Wookhyun, Yang, Kee-Young
Autonomous Vehicle Engineering: September 201919AVEP099/5/2019
Editorial The new 'face' of privacy The Navigator No trust in AI systems without data protection Innovation Nation In the mobility space, Israel is rivaling Silicon Valley for smarts and start-ups - and beats it in chutzpah. Autonomy in your Face Biometric technology is deemed essential to ensuring AV driving safety and advancing the user experience-if privacy issues don't derail its deployment. About Face! To win acceptance, deployment of facial-recognition technology needs to fit within a picture-perfect consumer and legal framework that balances benefits with privacy protection. The Vehicle as Gaming Device Audi spin-off Holoride uses VR to turn the back seat into an entertainment platform. BlackBerry Tech Duo Sees Emergence of Vehicle-based Platforms Though likely to provide the OS of autonomy, BlackBerry also anticipates a larger shift to automobiles as software platforms. Improving Lidar - or Defeating It The buzz at Sensors Expo pitted lidar-tech optimism against the reality of an impending shakeout. 'Smart' in Ohio's Heartland With a 45-year history in vehicle testing, Ohio's Transportation Research Center launches a $45-million investment in the automated-vehicle future, becoming North America's largest dedicated AV test facility. Empathy to Elevate the User Experience Harman developers are striving to create human-machine interfaces oriented more towards user needs. ZF's Tech Portfolio is Ready for Level 4 Autonomy Well aware of the relentless hype that comes with automated driving development, ZF's autonomy boss knows cost will be crucial-and customer persuasion required. Trucking Without Truckers The challenges are myriad, but automated-trucking developer TUSimple believes the efficiencies of true depot-to-depot driverless hauling are too promising to ignore.
Photogrammetric Frost Roughness Measurements in Cold-Soaked Conditions2019-01-19706/10/2019
Cold-soaked fuel frost (CSFF) is a form of aircraft wing contamination that occurs when a vehicle caries sufficient fuel for multiple trips or take-offs and landings. Following the first trip, which may reach altitudes above 10,000 m (33,000 ft), the fuel for the subsequent trips is carried in the wing tanks and may reach temperatures below -25 °C. In certain times of the year at some airports, temperatures and humidity levels will form CSFF on the aircraft wing surfaces over the fuel tanks. Unless an exemption is granted for the specific aircraft model, aircraft are not allowed to takeoff if the wing surfaces are contaminated by frost. Because aircraft operators desire to minimize vehicle time spent at airports, aircraft manufacturers are expected to pursue designs that safely operate with CSFF at takeoff and to pursue certification exemptions for aircraft models enabling CSFF takeoffs. To assist manufacturers in the design of future aircraft and to assist regulators in evaluating certification exemption requests, more information about frost roughness characteristics and evolution in CSFF conditions is required. However, because of the material and optical properties of frost, measuring CSFF properties using traditional roughness measurement presents challenges. For this investigation, a photogrammetric approach based on “structure-from-motion” algorithms traditionally employed in aerial surveying was developed to characterize the evolution of CSFF roughness. Using the approach, measurements of frost roughness evolution were performed in the Baylor Frost Tunnel (BFT) for two basic air temperature, humidity, surface temperature, and velocity conditions with frost time up to two hours. An analysis of variance approach was used to determine the sensitivity frost growth rates to the environmental conditions. The resulting measurements demonstrate different evolution histories with air velocity and air temperature being the most important factors governing roughness growth.
Miyauchi, Taber, McClain, Stephen T., Zhang, Tongxin, O'Neal, Dennis L., Riley, James T.
Type IV Anti-Icing Fluid Subjected to Light Freezing Rain: Visual and Thermal Analysis2019-01-19716/10/2019
Deicing the aircraft using fluid, prior takeoff is mandatory; since a thin layer of ice or snow can compromise the safety. With the same idea, to use anti-icing fluid during a frozen precipitation to protect the aircraft is also essential. Commercialized anti-icing fluids all pass the process of qualification as described in the SAE documents. One of these documents specifies a set of tests that reproduce freezing precipitation to obtain endurance time and then the holdover timetables. The endurance time is determined by visual inspection: when 30% of the plate is covered with frozen contaminants. With the evolution of technology and the venue of new tools, it may simplify the process, and at least confirm the observations. This paper proposed a thermal and visual analysis of the behavior of a Type IV fluid subjected to light freezing rain. During the precipitation, the plate temperature is measured with thermocouples and recorded using a visual camera and an IR camera. The use the visual camera in conjunction with the IR camera allowed to understand how the water drops interacted with the fluid and also to confirm the presence of frozen contaminants. The use of IR camera can be useful for the industry; however experimentation needs to be done before.
Brassard, Jean-Denis, Laforte, Caroline, Volat, Christophe
Runway Deicing Product Anti/Deicing Performance Assessment: Review and Future Directions2019-01-19746/10/2019
Every winter, northern airport operations are disrupted by heavy snowstorms and freezing precipitations. A simple snow accumulation or a thin layer of ice can affect aircraft operations (take-off, landing and taxi), and increase the risk for passengers and crew members, by rendering the runway slippery. Any deficits in deicing operations can also lead to flight delays and even cancellations that cost a lot to the industry. In order to maintain the runway and taxiway in a safe and useable condition, airport authorities use mechanical tools, but also chemical products. Chemical products available on the market for use in airports are principally in solid forms and liquid form, and are denominated as Runway Deicing Product (RDP). All of the products used in airport should meet the technical requirements of one of the two Aerospace Materials Specifications (AMS) documents: the AMS1431D Compound, Solid Runway and taxiway Deicing/Anti-icing and the AMS1435C Fluid, Generic, Deicing/Anti-icing Runways and Taxiways. Most of the products are used as freezing point depressants and are applied on snow, ice or packed snow covers to create holes and facilitate the mechanical removal. Over the past ten years, efforts have been brought along to adapt and to develop methods in order to assess the deicing and the anti-icing performance of the products. Some of those methods are included in actual SAE documents and some are in development. This paper will present a review of those methods and also cover the future directions of the research and development in the field.
Brassard, Jean-Denis, Laforte, Caroline, Tremblay, Marc Mario, Volat, Christophe
Radar Detection of High Concentrations of Ice Particles - Methodology and Preliminary Flight Test Results2019-01-20286/10/2019
High Ice Water Content (HIWC) has been identified as a primary causal factor in numerous engine events over the past two decades. Previous attempts to develop a remote detection process utilizing modern commercial radars have failed to produce reliable results. This paper discusses the reasons for previous failures and describes a new technique that has shown very encouraging accuracy and range performance without the need for any modifications to industry’s current radar design(s). The performance of this new process was evaluated during the joint NASA/FAA HIWC RADAR II Flight Campaign in August of 2018. Results from that evaluation are discussed, along with the potential for commercial application, and development of minimum operational performance standards for future radar products.
Harrah, Steven, Strickland, Justin, Hunt, Patricia, Proctor, Fred, Switzer, George, Ratvasky, Thomas, Strapp, J. Walter, Lilie, Lyle, Dumont, Christopher
A Study of Droplet Breakup in the Vicinity of an Airfoil2019-01-20006/10/2019
Supercooled large droplets can breakup before imping on aerodynamic surfaces and this should be taken into account in the icing codes. A study of droplets breakup in the vicinity of an airfoil has been conducted. Experiments for streams of droplets that were allowed to fall in the path of an incoming airfoil attached to a rotatory arm were conducted at the INTA facility. Droplets diameters ranged from 500 μm to 3 mm and two airfoils models of leading edge radius of 70 mm and 103 mm moving at velocities of 70 m/s, 80 m/s and 90 m/s were tested. Two subsets of experimental data for both bag and stamen breakup and shear breakup modes were used in this investigation. For these cases a numerical trajectory and deformation model was applied to obtain the evolution of the horizontal position, and the droplet maximum and minimum diameter. Breakup onset was determined from experimental data. Though previous works considered that breakup starts when there is a minimum in the minimum diameter, such minimum was not found in the integration of the model. However, it was found a minimum in the derivative of the minimum diameter at the breakup onset. The implication of this finding has been discussed. Additionally, the minimum in the derivative of the minimum diameter is compared to a previous empirical breakup criterion and the results of the comparison have been discussed.
Sor, Suthyvann, Garcia-Magariño, Adelaida, Velazquez, Angel
Icing Test and Measurement Capabilities of the NRC’s Gas Turbine Laboratory2019-01-19436/10/2019
The National Research Council’s Gas Turbine Laboratory provides industry leading icing facilities that allow manufacturers to develop, validate and certify new products for flight in adverse conditions. This paper shows how NRC measurement techniques are used across the facilities, and presents a literature-review of recently developed capabilities. The overview includes new details on some facilities, and future capabilities that are in development or planned for the near future. Methods developed at the NRC for characterizing inclement conditions are discussed and include the Isokinetic Probe, Particle Shadow Velocimetry, the Particle Detection Probe, and a size-binned real-time thermodynamic evaporation model. These are used to deliver accurate icing water content in facilities like the sea-level ice crystal generator, the Rotating Icing Rig, the Research Altitude Testing Facility, and liquid water test facilities in Ottawa and in Thompson, Manitoba at the Global Aerospace Centre for Icing and Environmental Research (GLACIER).
Chalmers, Jennifer, Davison, Craig, MacLeod, James, Neuteboom, Martin, Fuleki, Dan
Simulations of Thin Film Dynamics on a Flat Plate and an Airfoil2019-01-19386/10/2019
The goal of the present study is to investigate the dynamics of a thin water film on a flat plate and an airfoil using direct numerical simulation (DNS). The first case for a wetted flat plate is used to model former experiments and investigate the dynamics of a wind-driven water film. The second case for a thin film on a NACA 0012 airfoil of chord length 0.5 m is used to investigate the dynamics of a wind-driven water film on a curved surface. Particular attention is paid to the interaction between the liquid film and the air shear-layer above the film. As the incoming airflow moves over the thin water film, instability is triggered at the gas-liquid interface. Interfacial waves develop and are advected downstream. The interaction between the air flow and the interfacial waves induces shedding vortices near the interface, which in turn perturb the liquid film farther downstream. Simulations are performed using the open source multiphase flow solvers, Gerris and Basilisk. Both solvers employ a finite-volume approach and the interface is captured using a Volume-of-Fluid (VOF) method. While the long-term goal of this research effort is to investigate glaze ice formation in water films on airfoils, the current simulations focus on liquid film dynamics starting with a constant thickness exposed to a relatively low flight airspeed. The resulting simulations demonstrate the unsteady film dynamics and thickness evolution and natural waviness generated by the liquid-film and free-stream flow interactions.
Sakakeeny, Jordan, McClain, Stephen T., Ling, Yue
Experimental Processing of Methodical Questions of Modeling the Atmospheric Cloud Containing Ice Crystals and Mixed Phase2019-01-19226/10/2019
In Central Institute of Aviation Motors (Moscow, Russia) over the past few years, work has been carried out on upgrading the test cell to simulate the conditions of ice crystals and mixed phase in accordance with regulatory requirements. The key feature of this test cell is that it is a high-altitude climate test rig with the possibility of creating altitude conditions up to an altitude of 15 km, as well as creating a high-speed stream up to 0.85 Mach number and temperatures up to −40°С. The diameter of the wind tunnel of this test cell is 1.02 meters. The layout of the test rig includes a manifold for bringing ice crystals into the stream, as well as a water spray manifold. With the help of a water spray manifold, it is possible to produce supercooled droplets in the stream. Using two collectors at once gives opportunity to create a wide range of conditions for both ice crystals and mixed phase. Ice crystals are obtained by the method of mechanical crushing of an ice bar by a cylindrical cutter. It is possible to obtain the required median size of ice crystals MVD = 50…200 μm by changing the feed rate of the bar, as well as the frequency of rotation of the cutter. It is also possible to adjust the flow of ice crystals. Methodical study of the calibration tests issues of stream containing ice crystals was performed. Cloud uniformity distribution was received for three different methods.
Goriachev, Aleksei, Zhulin, Vadim, Goriachev, Pavel, Grebenkov, Sergei, Savenkov, Vladimir
Influence of Freestream Temperature on Ice Accretion Roughness2019-01-19936/10/2019
The influence of freestream static temperature on roughness temporal evolution and spatial variation was investigated in the Icing Research Tunnel (IRT) at NASA Glenn Research Center. A 53.34 cm (21-in.) NACA 0012 airfoil model and a 152.4 cm (60-in.) HAARP-II business jet airfoil model were exposed to Appendix C clouds for fixed exposure times and thus fixed ice accumulation parameter. For the base conditions, the static temperature was varied to produce different stagnation point freezing fractions. The resulting ice shapes were then scanned using a ROMER Absolute Arm system and analyzed using the self-organizing map approach of McClain and Kreeger. The ice accretion prediction program LEWICE was further used to aid in interrogations of the ice accretion point clouds by using the predicted surface variations of local collection efficiency. The resulting equivalent sand-grain roughness heights predicted using the correlation of Flack and Schultz are compared to the roughness correlation employed in LEWICE for roughness convection enhancement predictions. The results demonstrate the influence of the stagnation point freezing fraction on the maximum sand-grain roughness height. A new function is developed to predict the maximum sand-grain roughness height based on the stagnation point freezing fraction and accumulation time.
McClain, Stephen T., Vargas, Mario, Tsao, Jen-Ching, Broeren, Andy
A Continuing Investigation of Diurnal and Location Trends in an Ice Crystal Icing Engine Event Database2019-01-19646/10/2019
Due to ongoing efforts by the aviation industry, much has been learned over the last several years regarding jet engine power loss and compressor damage events caused by the ingestion of high concentrations of ice crystal particles into the core flow path. Boeing has created and maintained a database of such ice crystal icing (ICI) events to aid in analysis and further study of this phenomenon. This article provides a general update on statistics derived from the Boeing event database, and provides more details on specific event clusters of interest. A series of three flight campaigns have, over the past five years, collected in-situ data in deep convective clouds that will be used for the assessment of the new FAA CFR Part 33 ice crystal environmental envelope Appendix D, and the equivalent EASA CS-25 Appendix P. The most recent Boeing engine event study in 2015 focused on oceanic cloud systems that caused events in Southeast Asia, a region expected to have similar cloud properties as the first flight campaign in Darwin, Australia. The current study will examine ICI engine events over South America and Africa, which are caused by large deep convective continental clouds of the type that were not the main focus of the three Appendix D/P flight campaigns. Continental event clouds are compared to the previously studied oceanic event clouds, in order to ascertain whether any systematic differences exist that should be considered when assessing the representativeness of the flight campaign datasets. The results may also be useful to those developing nowcasting algorithms identifying high ice concentration regions using satellite measurements.
Bravin, Melissa, Strapp, J. Walter
Gear System Parameters and Its Influence on Gearbox Noise2019-01-15626/5/2019
Tonal noise due to gears is one of the fundamental noise problems in a gearbox. Gear tooth deflections generate dynamic forces that lead to unwanted load fluctuations, thus noise. Different factors that are considered to control this noise, some to mention like proper gear macro design, microgeometry corrections, and housing compliance. However, identifying the appropriate variable as a measure of contribution to the overall response helps in getting more accurate remedial solutions. Some outputs to track are different harmonic components of TE, temperature effects, components of forces, rim compliance and friction. For evaluation, usually, the amplitudes of individual harmonics of transmission error are related to the respective orders of the noise levels assuming it as one of the primary excitation parameters of gear noise. In this paper, a brief overview of TE and its harmonic distribution is discussed with the example of an ideal gear mesh model and then quantifying TE with the introduction of mesh misalignment. The effect of providing additional microgeometry corrections to compensate for the misalignment is also discussed. The study in this paper discusses the influence of parameters that are associated with gear whine and will serve as a guideline for the optimizing the gear design. The analysis was performed on a simple external helical gear mesh model in LDP tool for generating loads and TE. Moreover, the radiated noise from the flexible housing was also monitored to study the influence of different parameters on the sound power levels. Some additional results were evaluated with an in-house developed tool as well. The studies performed in this paper will help in identifying the parameters for transmission durability & NVH also their importance in designing quiet and robust gearbox.
Dewangan, Yogesh Kumar, Nair, Pranoy Sureshbabu, Nair, Dipin
The History of Laminated Steel2019-01-15786/5/2019
This paper discusses the background and history of “laminated steel” (commonly called “noiseless steel” or MPM). It provides the early development, where it came from, and how it was introduced to North America as a new tool for engineering acoustical solutions. A progressive timeline shows laminated steel from its earliest inception in Europe to its current role in today’s global market. Case histories along with examples of successful applications detail its important contribution in advancing the technology for component damping. Many manufacturing sources as well as end users have been impacted over the decades since it was first introduced. Some of those companies will be noted. The background information for this paper is provided by many of the individuals who were involved in the very early stages of its introduction as well those who are currently working to utilize the technology of laminated steel.
Huckins, Dennis, Jackson, Peter, Shedlowsky, James
Determining Vibro-Acoustic Characteristics and Structural Damping of an Elastic Monolithic Panel2019-01-15386/5/2019
Evaluations of the dynamic and acoustic responses of panels, partitions, and walls are of concern across many industries, from building home appliances, planning meeting rooms, to designing airplanes and passenger cars. Over the past few decades, search efforts for developing new methodologies and technologies to enable NVH engineers to acquire and correlate dynamically the relationship between input excitations and vibro-acoustic responses of arbitrary-shaped panels has grown exponentially. The application of a particular methodology or technology to the evaluation of a specific structure depends intimately on the goals and objectives of the NVH engineers and industries. In this work, we present the comparisons between the traditional modal analyses for structural vibrations together with sound intensity measurements of sound radiation and a laser-assisted Helmholtz equation least squares (HELS) method [1, 2, 3, 4] to characterize the dynamic and acoustic responses of an arbitrarily shaped structure subject to non-contact acoustic excitations. Input data for the latter include the normal surface velocities measured at a finite number of points on the surface of the structure that are accessible to a laser beam, and the acoustic pressures measured at a few points in the near field. With these input data, we will be able to reconstruct the normal surface velocity, the surface acoustic pressure, the normal surface acoustic intensity distributions over the entire structure, dimensionless structural damping ratio spectrum, sound transmission losses (STL), and sound transmission paths, etc. These data enable engineers to acquire a comprehensive understanding of the vibro-acoustic characteristics of any arbitrarily shaped vibrating structure, which can lead to the most cost-effective NVH reduction.
Figueroa, Antonio, Wu, Sean, Chen, Lingguang
Accuracy and Sensitivity of Yaw Speed Analysis to Available Data2019-01-04174/2/2019
Accident reconstructionists rarely have complete data with which to determine vehicle speed, and so the true value must be bracketed within a range. Previous work has shown the effect of friction uncertainty in determining speed from tire marks left by a vehicle in yaw. The goal of the current study was to assess improvements in the accuracy of vehicle speed estimated from yaw marks using progressively more scene and vehicle information. Data for this analysis came from staged S-turn maneuvers that in some cases led to rollover of sport utility vehicles. Initial speeds were first calculated using the critical curve speed (CCS) formula on the yaw marks from the first portion of the S-maneuver. Then computer simulations were performed with progressively more input data: i) the complete tire marks from the whole S-maneuver, ii) measured vehicle mass, iii) measured suspension stiffness and damping, and iv) measured steering history. Simulations based on the complete tire marks reduced the average error compared with the CCS equation if measured accelerations were also matched. Adding the remaining input data to the simulations did not further improve the accuracy of the reconstructed vehicle speed.
Heinrichs, Bradley, Lee, Janice, Young, Cole
Influence of DISH, Ankylosis, Spondylosis and Osteophytes on Serious-to-Fatal Spinal Fractures and Cord Injury in Rear Impacts2019-01-10284/2/2019
Seats have become stronger over the past two decades and remain more upright in rear impacts. While head restraints are higher and more forward providing support for the head and neck, serious-to-fatal injuries to the thoracic and cervical spine have been seen in occupants with spinal disorders, such as DISH (diffuse idiopathic skeletal hyperostosis), ankylosis, spondylosis and/or osteophytes that ossify the joints in the spine. This case study addresses the influence of spinal disorders on fracture-dislocation and spinal cord injury in rear impacts with relatively upright seats. Nineteen field accidents were investigated where serious-to-fatal injuries of the thoracic and cervical spine occurred with the seat remaining upright or slightly reclined. The occupants were lap-shoulder belted, some with belt pretensioning and cinching latch plate. The occupants were older and had pre-existing disorders of the spine, including DISH, ankylosis, spondylosis and/or osteophytes that ossify the spinal joints. The crashes were summarized and the mechanism for injury was analyzed. The 19 cases involved fracture-dislocation and spinal cord injury at areas of the spine where DISH, ankylosis, spondylosis and/or osteophytes ossified the intervertebral soft tissues causing stiff and brittle joints that were vulnerable to fracture-dislocation by straightening of the spine. Published sled tests at 40 km/h (25 mph) with the 50th Hybrid III showed that peak chest acceleration was 13.5 ± 2.4 g (n=7) and head acceleration was 26.0 ± 12.0 g (n=8). Sled testing at 16 km/h (10 mph) with the BioRID IIg involved T1 x-accelerations of 12.6 ± 2.4 g (n=12) and head x-accelerations of 10.1 ± 0.2 g (n=12). These levels of acceleration are sufficient to fracture the calcified spine of the older occupants without ramping or moving off the support from the seatback and head restraint. A new injury mechanism for spinal fracture-dislocation is described in older occupants with spinal disorders. The occupant remains supported by the relatively upright seatback and high and forward head restraint. The accelerations that bring the occupant up to the delta V are sufficient to fracture-dislocate the calcified spine that tries to straighten in the crash.
Viano, David, Parenteau, Chantal, White, Samuel
Two Phase Heavy Truck Acceleration Model2019-01-04114/2/2019
There have been several papers published over the past 25 years regarding the acceleration of heavy trucks, including different loading conditions, drivetrain configurations, and driving techniques. The papers provide a large data set that measures the speed, distance, and time of the vehicles during acceleration testing and present the data in tabular or graphical formats. Although the data as presented can be useful, it can be challenging to pore over all the data to determine the correct set for a specific application in accident reconstruction. As of this paper’s date of publication, there are approximately eight relevant papers with a total of 268 acceleration tests performed, spanning many years. This paper reviews all the available published literature and summarizes the relevant data in a comprehensive list of accelerations for different heavy truck configurations, which provides a valuable resource to the accident reconstruction field.
Danaher, David, McDonough, Sean, Donaldson, Drew
Analysis of Rear Seat Sled Tests with the 5th Female Hybrid III: Incorrect Conclusions in Bidez et al. SAE 2005-01-17082019-01-06184/2/2019
Objective: Sled test video and data were independently analyzed to assess the validity of statements and conclusions reported in Bidez et al. SAE paper 2005-01-1708 [7]. Method: An independent review and analysis of the test data and video was conducted for 9 sled tests at 35 km/h (21.5 mph). The 5th female Hybrid III was lap-shoulder belted in the 2nd or 3rd row seat of a SUV buck. For one series, the angle was varied from 0, 15, 30, 45 and 60 deg PDOF. The second series involved shoulder belt pretensioning and other belt modifications. Results: Bidez et al. [7] claimed “The lap belts moved up and over the pelvis of the small female dummy for all impact angles tested.” We found that there was no submarining in any of the tests with the production lap-shoulder belts. Bidez et al. [7] claimed “H3-5F dummies began to roll out of their shoulder belt at… 30 degrees. Complete loss of torso support was seen at 45 degrees without significant kinetic energy dissipation.” We found that the shoulder belt remained in place and restrained the upper torso in the 0, 15 and 30 deg sled tests. At 45 and 60 deg, significant restraint was provided before the belt slipped off the shoulder. It remained in contact with the arm and chest providing restraint. Bidez et al. [7] claimed “The results indicated kinematic movement of the dummies, which were predictive of injury in all sled runs.” We found that the kinematic control was good and the biomechanical responses were well below IARVs for the 5th female Hybrid III. Bidez et al. [7] claimed “a retractor pretensioner (7 ms fire time) eliminated both submarining and torso rollout in the H3-5F in the conditions tested.” We found that the pretensioner firing pulled the lap belt up onto the abdomen inducing submarining and causing abdominal loading in two out of four tests. Conclusion: The independent review of the videos and data shows that Bidez et al. [7] misstated the results, misrepresented the findings and reached incorrect conclusions on the testing.
Viano, David, Parenteau, Chantal
Low Pressure-Driven Injection Characterization for SCR Applications2019-01-09944/2/2019
Aqueous Urea is a non-toxic and stable ammonia carrier and its injection and mixing represent the basis for the most common de-NOx technology for mobile applications. The reactant feed preparation process is defined by evaporation, thermolysis and hydrolysis of the liquid mixture upstream the Selective Catalytic Reduction reactor, and it is strongly dependent on the interaction between spray and gaseous flow. Low-pressure driven injectors are the common industrial standard for these applications, and their behavior in almost-ambient pressure cross flows is significantly different from any in-cylinder application. For this reason, two substantially different injectors in terms of geometry and design are experimentally studied, characterizing drop sizes and velocities through Phase Doppler Anemometry (PDA) and liquid mass spatial distribution through Shadow Imaging (SI). The measurements involve the analysis of the spray in quiescent air conditions, gathering information at the closest to the nozzle reliable location. Distilled water and Urea Water Solution are characterized, clearly showing that the spray evolution is only slightly affected by the mixture composition. These experimental findings act as the basis for the construction of a numerical description of liquid injection within the Lagrangian tracking framework inside 3D finite volume CFD simulations. A robust injection model is defined, pointing out the singularities of the system and identifying the most critical aspects. The proposed model is built on the direct definition of a droplet diameter distribution, putting particular attention in the droplet-to-parcel ratio definition. One of the two injectors is taken as the input and the other one, which shows a considerable different design and spray pattern is used as a test for the modeling approach. The simulation setup is then assessed in cross-flow conditions and validated on data gathered in a synthetic exhaust gas test bench, where the injectors are installed in an optically accessible chamber, allowing PDA and SI measurements over a wide range of thermal and kinematic cross flow conditions, representative of typical Diesel after-treatment systems. Good agreement with the experimental data is obtained, highlighting how the definition of the initial spray droplet kinematic properties is the key feature in the correct description of a spray for SCR applications, regardless of the Urea mass fraction in the mixture. The evolution of the liquid plume inside a realistic after-treatment channel size geometry shows that most of the momentum of the spray is carried by the largest droplets, which are the ones to be correctly described to address important issues in the Urea Water Solution dosing; these are responsible for the excessive wall impingement and subsequent formation of solid deposits. Specific care is applied in the definition of a reasonable CFD framework, determining mesh sizes and sub-model setups able to fulfill affordable computational costs, according to the current industrial standards.
Nocivelli, Lorenzo, Montenegro, Gianluca, Dimopoulos Eggenschwiler, Panayotis
Risk of Concussion in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions Evaluated Using Head Acceleration-Based Metrics2019-01-12184/2/2019
Over the past decade, there has been an increase in awareness and concern about the occurrence and long-term effects of concussions. Traumatic brain injury (TBI)-related emergency department (ED) visits associated with motor vehicle collisions, including patients with a diagnosis of concussion or mild TBI (mTBI), have increased while deaths and hospital admissions related to TBI have decreased. The diagnostic criteria for concussion have evolved and broadened, and based on current assessments and diagnostic imaging techniques, there are often no objective findings, yet a diagnosis of concussion may still be rendered. Clinical assessment of concussion may be based only on patient-reported symptoms and history, making it difficult to objectively relate the reported increase in TBI-related ED visits due to motor vehicle collisions to specific collision parameters. This study aims to perform a scientific evaluation of concussion risk during motor vehicle collisions, strengthened by objective, quantitative data, specifically focusing on head acceleration-based metrics. Data from full-scale passenger vehicle crash tests are reported for frontal and rear-end collisions with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to 11.8 mph) and 5.6 to 19.5 kph (3.5 to 12.1 mph), respectively. Head linear and rotational kinematic data were recorded from instrumented Hybrid III 50th percentile male anthropomorphic test devices (ATDs) restrained in the driver’s seats. Several acceleration-based metrics currently used to assess risk of concussion were calculated and compared to published injury risk relationships that have been developed from field accident data, human subjects, and biomechanical models. Overall, the magnitudes of acceleration were low and the injury metrics corresponded to a negligible risk of concussion in these low- to moderate-speed collisions.
Pasquesi, Stephanie A., Bruno, Alexander, Courtney, Amy, Imler, Stacy M., Smedley, Janine, Prange, Michael T.
A Study of the Performance of Automatic Emergency Braking (AEB) Systems Equipped on Passenger Vehicles for Model Years 2013 to 20182019-01-04164/2/2019
Over the past decade, manufacturers have introduced vehicles equipped with Automatic Emergency Braking (AEB) into the North American market. These vehicles have the capability to not only detect an impending collision and warn the driver, but also to initiate braking independent of the driver. The collision avoidance strategies used by the various manufacturers have not been studied extensively. In 2013, the Insurance Institute for Highway Safety (IIHS) began testing vehicles equipped with AEB in rear-end collision situations in order to issue their front crash prevention safety ratings for these vehicles. To date, over 180 vehicles from 31 manufactures spanning model years 2013 to 2018 have been tested. This paper presents an analysis of the data collected in these tests. The objective of the study was to assess the differences in performance and strategies used, at two different closing speeds, between manufacturers. The difference in strategies included differences in braking rates and timing of the onset of braking. With more vehicles being equipped with AEB systems each year, this study will be a valuable resource for collision reconstructionists to understand the performance of these systems.
Miholjcic, Djordje, Fabbroni, Mark, Robinson, Richard
Consideration of Corrosion Behavior of Aluminum Wire at Crimped Terminal and Effective Anti-Corrosion Treatment2019-01-04864/2/2019
The demand for weight reduction of vehicles is growing in compliance with CO2 emission control requirements. Also, demand for copper is on the rise with an increase in the number of electric vehicles because their motors and wiring require a lot of copper. This has raised concerns about higher copper prices and vehicle weight. Recently, attempts to reduce vehicle weight have been actively made by partially replacing copper with aluminum, which is lighter and less expensive. Although the use of aluminum wires on limited areas of some vehicles has already been reported, that on all areas has not been reported yet. The authors focus on reducing weight of wiring harnesses, which is about 20 kg per vehicle, and consider using aluminum instead of copper as the conductor of the electrical wires. One of the factors impeding the use of aluminum wires in wider areas is galvanic corrosion occurring at crimped terminals. Since aluminum causes galvanic corrosion when the metal is in electrical contact with a different metal in an electrolyte, it is essential to prevent this phenomenon from occurring at crimped terminals in mounting aluminum wires on vehicles. An anti-corrosion treatment needs to effectively prevent the occurrence of corrosion at the locations where aluminum wires are used. To devise an appropriate anti-corrosion treatment, it is necessary to grasp how aluminum wires corrode at the crimped terminals. This paper describes findings from a study of corrosion behavior of aluminum wires at crimped terminals for the purpose of developing an effective anti-corrosion treatment to increase the area onto which aluminum wires can be used.
Kawaguchi, Takuya, Fukaura, Keiji, Nakamura, Yuki, Mochizuki, Makoto, Otani, Satoshi
Reconstructing Vehicle Dynamics from On-Board Event Data2019-01-06324/2/2019
Modern vehicles record dynamic data from a number of on-board sensors for events that could precede a crash. These data can be used to reconstruct the behavior of a vehicle, although the accuracy of these reconstructions has not yet been quantified. Here, we evaluated various methods of reconstructing the vehicle kinematics of a 2017 and a 2018 Toyota Corolla based on Vehicle Control History (VCH) data from overlapping events generated by the pre-collision system (PCS), sudden braking (SB) and anti-lock brake (ABS) activation. The vehicles were driven towards a stationary target at 32-64 km/h (20-40 mph) and then after the pre-collision alarm sounded the vehicle was steered sharply right or left and braked rapidly to rest. VCH data for PCS event were recorded at 2 Hz and for the sudden braking and ABS activation events at 6.7 Hz. The steering wheel angle and the vehicle’s longitudinal acceleration, lateral acceleration, and angular rate data were extracted and used to predict the vehicle position and heading over the duration of the VCH data record preceding the vehicle coming to rest. These predictions were generated by directly integrating the VCH data and by using the VCH data as inputs to PC-Crash simulations. The predicted positions and headings were then compared to the actual position and heading data measured using differential GPS synchronized to the VCH data record. The results of these analyses provide insights into the best methods for reconstructing vehicle kinematics from VCH data and estimates of the errors associated with different reconstruction techniques.
Tsuge, Brandon, Yang, Mike, Flynn, Thomas, Xing, Peter, Lawrence, Jonathan, Heinrichs, Bradley, Siegmund, Gunter
Quantification of Sternum Morphomics and Injury Data2019-01-12174/2/2019
Crash safety researchers have an increased concern regarding the decreased thoracic deflection and the contributing injury causation factors among the elderly population. Sternum fractures are categorized as moderate severity injuries, but can have long term effects depending on the fragility and frailty of the occupant. Current research has provided detail on rib morphology, but very little information on sternum morphology, sternum fracture locations, and mechanisms of injury. The objective of this study is two-fold (1) quantify sternum morphology and (2) document sternum fracture locations using computed tomography (CT) scans and crash data. Thoracic CT scans from the University of Michigan Hospital database were used to measure thoracic depth, manubriosternal joint, sternum thickness and bone density. The sternum fracture locations and descriptions were extracted from 63 International Center for Automotive Medicine (ICAM) crash cases, of which 22 cases had corresponding CT scans. The University of Michigan Internal Review Board (HUM00043599 and HUM00041441) approved the use of crash cases and CT scan data. The sternum morphomics data showed the thoracic depth increased, except for the 60-74-year-old age group. The average sternum thickness was greater in the older age groups. The sternum bone density decreased from youngest to oldest age groups. The angle between the manubrium and the sternum body decreased by 5.6° between the youngest and oldest age groups. The frequency of sternum fractures increased after age 45. Fractures were most frequent in the sternum body. The seat belt webbing was coded as the source of 54% of the sternum fractures.
Bunn, Barbara, Johannson, Suzanne, Kohoyda-Inglis, Carla, Wang, Stewart, Parenteau, Chantal, Holcombe, Sven
Review of the Computer Science and Engineering Solutions for Model Sharing and Model Co-Simulation2019-01-13523/19/2019
The process of developing, parameterizing, validating, and maintaining models occurs within a wide variety of tools, and requires significant time and resources. To maximize model utilization, models are often shared between various toolsets and experts. One common example is sharing aircraft engine models with airframers. The functionality of a given model may be utilized and shared with a secondary model, or multiple models may run collaboratively through co-simulation. There are many technical challenges associated with model sharing and co-simulation. For example, data communication between models and tools must be accurate and reliable, and the model usage must be well-documented and perspicuous for a user. This requires clear communication and understanding between computer scientists and engineers. Most often, models are developed by engineers, whereas the tools used to share the models are developed by computer scientists. Computer scientists often struggle with implementing methods for exchanging data between models while simultaneously maintaining the usability that engineers desire, and engineers often struggle with utilizing the tools that computer scientists have developed. In the process of developing tools and interfaces for model sharing and co-simulation, much is lost in the communication between computer scientists and engineers. This paper seeks to ease the communication barrier associated with model sharing and model co-simulation by clearly and simply discussing some of the commonly associated challenges and solutions, and then providing clear and concise implementation examples.
Nelson-Weiss, Brendan, Krouse, Charles
Theoretical Modeling of the Mechanical Degradation of Polymer Composites due to Moisture/Water Absorption and Damage Progression2019-01-13763/19/2019
The moisture/water absorption and microvoids/cracks progression are two well-understood mechanisms that have significant degradation effects on the mechanical properties/behaviors of the polymer-based composites. To theoretically investigate the effects of above two mechanisms, we develop a simple fiber reinforced polymer composites model by employing the internal state variable (ISV) theory. The water content and the anisotropically distributed damage of the composites are considered as two ISVs (the water content is described by a scalar variable and the damage is defined as a second order tensor) whose histories are governed by two specific physically-based evolution equations. The proposed model can be easily cast into a general theoretical framework to capture more polymer composites behaviors such as viscoelasticity, viscoplasticity and the thermal effect. The results predicted by current model are in good agreement with the experimental data, which allows us to implement the model into FEA for future structural analysis.
He, Ge, Liu, Yucheng
A Process for Delivering Extreme AFP Head Reliability2019-01-13493/19/2019
Every now and then a good idea happens. The Modular head was a great idea and enabled the use of multiple types of AFP heads, ATL, ply cutting, part probing, etc. with the use of a single machine and machining cell. At the time the modular head was developed by Electroimpact circa 2004, the industry assumed (and accepted) that AFP was an unreliable process. It still isn’t as reliable as we’d like. One way of coping with this lack of reliability is to stage more than one head in the AFP cell so that a spare head of the exact same type is ready to jump into action if the head out on the floor has an issue. If the reliability of the AFP process were to increase 10x or 50x, would there still be a business case for the multiple AFP head system? The modular head may still win the day, but the metrics change. For instance, if there was only 20 minutes of down time for every head load, it may no longer be advantageous to have 2 heads of the exact same type in the cell. It is our goal to eliminate AFP process unreliability to the point where this discussion has real meaning. To address the #1 cause of reliability issues experienced in 777x we invented the Modular-Servo-Creel head. We built a full working prototype of this machine and demonstrated it to Boeing and others over the past year. What we learned was indeed we did fix the #1 cause of reliability issues that we see in production of the 777x spar (the loss of tension during large speed changes during the zero degree ply). In the process of using this head other causes for unreliability also came into view. They actually had nothing to do with the theory of operation of the head as we previously experienced with the old creel system, but more to do with preparation. These items are: Head Cleanliness Blade Sharpness A valve that is failing or leaking A seal that is worn or leaking A spring plate that failed Each of these items caused an error on a part that we were trying to make and diagnosis took longer than acceptable causing even more issues on the part until the correct diagnosis and remedy was made. Because we identified these items as potential causes of mistakes on the part, we created a system described in detail in this paper. This section describes a process and method for cleaning the AFP head using a dishwasher, a method for checking blade sharpness and finally a method for checking the module functionality. We demonstrate this this system running our prototype AFP head building 16 plys of the 50’ spar, some stringer charges and then a hexagonal test part placing 100,000 individual tow strips without a process error, not even a slipped tow.
Rudberg, Todd, Cemenska, Joshua, Sherrard, Ethan
The Impact of Gasoline Direct Injection System Design on PM Emissions2019-01-00721/15/2019
Gasoline Direct Injection engines can have significantly higher particulate mass (PM) and particulate number (PN) emissions relative to equivalent displacement Port Fuel Injected engines. Both the EPA and California Air Resources Board have adopted new stringent standards to be phased in over the next 10 years. The California regulations continue to tighten to a 1 mg/mi PM limit that is phased-in beginning with model year 2025 with full compliance by model year 2028. This study examines the different fuel injection system technology improvements that will be used to attain the standards to as well as their relative costs, market penetration potential, emission reduction and fuel economy impacts. The identification of alternative approaches and the analysis of their impacts was performed in two tasks. The first task was a comprehensive literature review and the findings of the review are presented. In the second task, information on topics not fully informed by the literature review was obtained from interviews with experts at auto-manufacturers and fuel system suppliers. The information from the interviews was integrated with the findings from the literature review to develop a comprehensive understanding of vehicle PM emissions and the pathways that manufacturers could follow to comply with the 1 mg/mi standard.
Duleep, K. Gopal
Heat of Vaporization and Species Evolution during Gasoline Evaporation Measured by DSC/TGA/MS for Blends of C1 to C4 Alcohols in Commercial Gasoline Blendstocks2019-01-00141/15/2019
Evaporative cooling of the fuel-air charge by fuel evaporation is an important feature of direct-injection spark-ignition engines that improves fuel knock resistance and reduces pumping losses at intermediate load, but in some cases, may increase fine particle emissions. We have reported on experimental approaches for measuring both total heat of vaporization and examination of the evaporative heat effect as a function of fraction evaporated for gasolines and ethanol blends. In this paper, we extend this work to include other low-molecular-weight alcohols and present results on species evolution during fuel evaporation by coupling a mass spectrometer to our differential scanning calorimetry/thermogravimetric analysis instrument. The alcohols examined were methanol, ethanol, 1-propanol, isopropanol, 2-butanol, and isobutanol at 10 volume percent, 20 volume percent, and 30 volume percent. The results show that total heat of vaporization of the alcohol gasoline blends is in line with the decreasing heat of vaporization in kilojoules per kilogram with increasing alcohol carbon number, as expected. Mass spectrometer results show that methanol fully evaporates at significantly lower fraction evaporated relative to other alcohols even though it is present at higher molar concentration at a fixed volumetric concentration. Certain alcohols, especially methanol and ethanol, can suppress the evaporation of aromatic compounds such as cumene during the evaporation process in some samples. While the use of mass spectrometry to analyze the composition of the evolving gas mixture provided useful results for a relatively simple research gasoline (FACE B), additional research is required to practically apply this methodology to more complex commercial gasolines.
Fioroni, Gina M., Christensen, Earl, Fouts, Lisa, McCormick, Robert
Model-Based Approaches in Developing an Advanced Aftertreatment System: An Overview2019-01-00261/15/2019
Cummins has recently launched next-generation aftertreatment technology, the Single ModuleTM aftertreatment system, for medium-duty and heavy-duty engines used in on-highway and off-highway applications. Besides meeting EPA 2010+ and Euro VI regulations, the Single ModuleTM aftertreatment system offers 60% volume and 40% weight reductions compared to current aftertreatment systems. In this work, we present model-based approaches that were systematically adopted in the design and development of the Cummins Single ModuleTM aftertreatment system. Particularly, a variety of analytical and experimental component-level and system-level validation tools have been used to optimize DOC, DPF, SCR/ASC, as well as the DEF decomposition device. The highlights of this work can be summarized as follows: a). internal dosing is more efficient than external dosing to control HC slip; High CPSI DOCs show better HC oxidation performance at high SV due to enhanced mass transfer; b). the adopted advanced DPF technologies enable greater ash capacity for long maintenance intervals; c). SCR performance was optimized with the use of a hydrothermally robust Cu-Zeolite catalyst coated on high CPSI substrates.
Su, Changsheng, Brault, Joseph, Munnannur, Achuth, Liu, Z. Gerald, Milloy, Sean, Harinath, Arvind, Dunnuck, David, Federle, Ken
Influence of Autoignition and Pressure Wave Behavior on Knock Intensity Based on Multipoint Pressure Measurement and In-Cylinder Visualization of the End Gas2018-32-000110/30/2018
In this study, the effect of autoignition behavior in the unburned end-gas region on pressure wave formation and knock intensity was investigated. A single-cylinder gasoline engine capable of high-speed observation of the end gas was used in the experiments. Visualization in the combustion chamber and spectroscopic measurement of light absorption by the end gas were carried out to analyze autoignition behavior in the unburned end-gas portion and the reaction history before autoignition. The process of autoignition and pressure wave growth was investigated by analyzing multipoint pressure histories. As a result, it was found that knocking intensity increases through interaction between autoignition and pressure waves.
Yamashita, Takahiro, Takahata, Shuhei, Kudo, Hiroki, Izako, Takuya, Ishikawa, Takahiro, Saito, Masanori, Tanabe, Mitsuaki, Iijima, Akira
Optimization of Slot Disc Shape for Improving Brake Fade Performance2018-01-188310/5/2018
Due to improvements in vehicle powertrain performance, friction material fade performance is becoming an important topic. For this reason, needs for studies to improve thermal characteristics of the brake system is increasing. Methods for improving the fade characteristics have several ways to improve the thermal characteristic of friction materials and increase disc capacity. However, increasing disc capacity(size) have some risk of weight and cost rise, and friction factor improvements in friction material tend to cause other problems, such as increasing squeal wire brush noise and increasing metal pick up on disc surface. Therefore, a slot disc study is needed to overcome the problems discussed previously. Currently, there is few research history for slot disc related to fade and metal pickup improvements. Through this study, I found that the slot disc improved the friction material fade properties, but the application of the slot disc could cause air plane noise and worsen the friction material wear characteristic this study shows that optimizing the number of slots and slot profile and slot direction on disc surface minimizes air plane noise and friction material wear characteristic.
Kim, Hyungjoon, Kim, Yoon Cheol, Seo, Hankyo, Seol, Jaekwang, Yoon, Chul, Kim, Kwang Yun
Structural Integrity of In-Wheel Motors2018-01-18299/10/2018
In-wheel motors offer an optimized solution for novel drivetrain architectures of future electric vehicles that could penetrate into the mainstream automotive industry, moving the wheel actuation where it’s required, directly inside the wheels. Obtainable literature mainly deals with optimization of electromagnetically active parts, however, mechanical design of electromagnetically passive parts that indirectly influence motor performance also requires detailed analysis and extensive validation. To meet the optimal performance requirements (also durable) of an in-wheel traction motor, their mechanical design requires topology optimization of housing elements, thermal mapping, geometrical and dimensional tolerance checks and selection of proper hub bearings, in order to assure consistent electromagnetic behavior stability The following paper uniquely describes the review of loads acting on an in-wheel motor, the workflow of a typical mechanical design process, testing, and validation processes for achieving the required durability of an in-wheel assembly.
Frajnkovic, Matic, Omerovic, Senad, Rozic, Uros, Kern, Jurij, Connes, Raphael, Rener, Kristof, Biček, Matej
Compression Ignition of Low Octane Gasoline under Partially Premixed Combustion Mode2018-01-17979/10/2018
Partially premixed combustion (PPC) is an operating mode that lies between the conventional compression ignition (CI) mode and homogeneous charge compression ignition (HCCI) mode. The combustion in this mixed mode is complex as it is neither diffusion-controlled (CI mode) nor governed solely by chemical kinetics (HCCI mode). In this study, CFD simulations were performed to evaluate flame index, which distinguishes between zones having a premixed flame and non-premixed flame. Experiments performed in the optical engine supplied data to validate the model. In order to realize PPC, the start of injection (SOI) was fixed at −40 CAD (aTDC) so that a required ignition delay is created to premix air/fuel mixture. The reference operating point was selected to be with 3 bar IMEP and 1200 rpm. Naphtha with a RON of 77 and its corresponding PRF surrogate were tested. The simulations captured the general trends observed in the experiments well. The flame index was noted to be an indicator to evaluate and quantify the in-cylinder combustion development under PPC engine operating condition. The evolution of premixed flames shows the same two-stage ignition behavior as the rate of heat release. Premixed flames are surrounded by the non-premixed fuel/air mixtures and distribute in the piston top-land region as isolated clouds. The proportion of premixed flames increases from low temperature heat release (LTHR) region first and decreases in negative temperature coefficient (NTC) region then increases to high temperature heat release (HTHR) region at PPC mode.
An, Yanzhao, Mubarak Ali, Mohammed Jaasim, Vallinayagam, R, AlRamadan, Abdullah, Sim, Jaeheon, Chang, Junseok, Im, Hong, Johansson, Bengt
A Review of the Requirements for Injection Systems and the Effects of Fuel Quality on Particulate Emissions from GDI Engines2018-01-17109/10/2018
Particulate emissions from Gasoline Direct Injection (GDI) engines have been an important topic of recent research interest due to their known environmental effects. This review paper will characterise the influence of different gasoline direct injection fuel systems on particle number (PN) emissions. The findings will be reviewed for engine and vehicle measurements with appropriate driving cycles (especially real driving cycles) to evaluate effects of the fuel injection systems on PN emissions. Recent technological developments alongside the trends of the influence of system pressure and nozzle design on injector tip wetting and deposits will be considered. Besides the engine and fuel system it is known that fuel composition will have an important effect on GDI engine PN emissions. The evaporation qualities of fuels have a substantial influence on mixture preparation, as does the composition of the fuel itself. Recently a number of studies have attempted to link fuel composition with PN emissions, developing a variety of indices including the PM index (Aikawa et al.) and the PN index (Leach et al.). An extensive literature search has been carried out and the PN index evaluated against these data. In addition the PM index and PN index are compared. The results of the review show that the Aikawa index should be applied when the fuel quality is known by lab reports, whereas the Leach index is relevant when only minimal information about a fuel is known, even the latter giving a relatively good prediction of PN emission trends from fuels in GDI engines.
Leach, Felix, Knorsch, Tobias, Laidig, Christoph, Wiese, Wolfram
Laser Powder Bed Fusion of Scaffolds for Orthopedic Applications: Design and ManufacturabilityTBMG-289195/1/2018
Metal additive manufacturing via laser powder bed fusion or electron beam melting has been used for several years for serial manufacturing of implants. The potential to seamlessly integrate porous volumes in orthopedic implants has provided medical design engineers a powerful tool to achieve superior implant performance. However, many opportunities to further optimize the design of these porous volumes remain unexplored or do not make it from the lab to industry. This article aims to provide a coherent view on the current use of porous volumes in additively manufactured implants and some of the most recent research in this field.
Diffusion Supporting Passive Filter Regeneration- A Modeling Contribution on Coated Filters2018-01-09574/3/2018
Wall flow particulate filters have been used as a standard exhaust aftertreatment device for many years. The interaction of particulate matter (PM) regeneration and catalytically supported reactions strongly depends on the given operating conditions. Temperature, species concentration and mass flow cause a change from advective to diffusive-controlled flow conditions and influence the rate controlling dominance of individual reactions. A transient 1D+1D model is presented considering advective and diffusive transport phenomena. The reaction scheme focuses on passive PM conversion and catalytic oxidation of NO. The model is validated with analytical references. The impact of back-diffusion is explored simulating pure advective and combined advective diffusive species transport. Rate approaches from literature are applied to investigate PM conversion at various operating conditions. Spatial NO/NO2 profiles over the cake/wall height and length are discussed and the transient evolution of axial cake heights is presented. The results reveal that the impact of back-diffusion on PM cake conversion cannot be purely assessed by the Péclet number. The comparison of different spatial coating designs shows that front-end coatings feature superior performance in passive PM cake conversion.
Wurzenberger, Johann C., Triebl, Christoph, Kutschi, Susanne
An Analytical Review and Extension of Two Decades of Research Related to PC-Crash Simulation Software2018-01-05234/3/2018
PC-Crash is a vehicular accident simulation software that is widely used by the accident reconstruction community. The goal of this article is to review the prior literature that has addressed the capabilities of PC-Crash and its accuracy and reliability for various applications (planar collisions, rollovers, and human motion). In addition, this article aims to add additional analysis of the capabilities of PC-Crash for simulating planar collisions and rollovers. Simulation analysis of five planar collisions originally reported and analyzed by Bailey [2000] are reexamined. For all five of these collisions, simulations were obtained with the actual impact speeds that exhibited excellent visual agreement with the physical evidence. These simulations demonstrate that, for each case, the PC-Crash software had the ability to generate a simulation that matched the actual impact speeds and the known physical evidence. Simulation of a full-scale rollover test reported by Asay [2010] is also examined. For this test, we obtained a simulation that exhibited an excellent visual match with the pre-roll tire marks and furrows and in which the vehicle rolled 7 times, just as it did in the actual test. The rest position of the vehicle was well matched, though a portion of the simulated roll trajectory did not match the actual roll trajectory. These areas of additional analysis extend the prior literature.
Rose, Nathan A., Carter, Neal
The Effect of Target Features on Toyota’s Autonomous Emergency Braking System2018-01-05334/3/2018
The Pre-Collision System (PCS) in Toyota’s Safety Sense package includes an autonomous emergency braking feature that can stop or slow a vehicle independent of driver input if there is an impending collision. The goals of this study were to determine how hazard characteristics, specifically radar reflector size and degree of target edge contrast, affect the response of the PCS, as well as to scrutinize tests wherein the PCS failed to stop the vehicle before impact. We conducted 80 tests with a 2017 Toyota Corolla driven towards a car-like target in a straight line and under constant accelerator pedal position, reaching about 30 km/h at the PCS alarm. Vehicle speed and distance to target at the alarm flag (ALM) and at times corresponding to three other system flags (PBA, FPB, and PB) were read from the Vehicle Control History records. Time to impact (TTI) at each flag was calculated and the distance between the stopped vehicle and the target was measured for each test. The PCS detected the hazard in all tests. We found that when there was little or no driver input, the PCS stopped the vehicle autonomously in all but one test. Target radar size and contrast did not affect the speeds, distances or TTIs in these tests. In some tests, the PCS and ABS interacted in a way that increased the stopping distance. In a small number of tests, the PCS disengaged partway through its algorithm and returned control to the driver for reasons that we were unable to discern. This study provides some initial insights into the dynamic response of the Toyota PCS and identifies some factors that affect its performance.
Yang, Mike, Xing, Peter, Flynn, Thomas, Tsuge, Brandon, Lawrence, Jonathan, Siegmund, Gunter P.
A Proposal to Re-architect Automotive OBD Freeze Frame Storage Requirements and the Associated Service-Oriented Freeze Frame Storage Algorithm Design2018-01-08724/3/2018
Automotive OBD freeze frame storage is mandated by regulations since the creation of OBD-II in 1994. The main purpose is to help service engineers to identify the cause of the associated fault. Although OBD regulations [1] have gone through multiple updates and major changes since 1994, the regulations requirements on freeze frame storage, however, remain almost the same. The flexibility to comply with the mandated requirements allows OEMs to come up with very different designs, and potentially would confuse the service engineers when repairing different powertrains and could compromise the main purpose of helping identify the root cause of faults. In 2015, GM fellows [2], together with SAE J1979 committee members, proposed a set of future requirements on the OBD freeze frame storage with the intention to standardize the requirements by mandating the rules what to store and when to store, the minimum number of frames, and the numbering of the frames. The proposal is better than the current requirements in terms of standardization and modernization, but it has several obvious shortcomings. For example, the minimum of four freeze frame storage will dramatically increase OEM’s costs and could potentially force OEMs to update their powertrain control units to have more storage capacity, and the downward compatibility with the current requirements is questionable. In addition, the prohibition of non-emission related faults in the freeze frames is not a service-friendly solution. Finally, the GM’s proposal gives no priority boarding for misfire or fuel system faults, which does not comply with the ARB CCR 1968.2 requirements. This paper proposes to re-architect the OBD freeze frame storage requirements with low cost to OEMs and downward compatibility to current requirements. In addition, a service-oriented freeze frame storage algorithm design is proposed based on the new requirements. This preliminary work offers OEMs an opportunity to extensively review theirs needs from service and designs and potentially will influence CARB to update the associated freeze frame requirements in the next version.
Guo, Yichao, LU, Wei, Terauchi, Kazumichi
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