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Viewing 241 to 270 of 21705
2015-04-14
Journal Article
2015-01-1187
Nils Lohmann, Peter Haussmann, Patrick Wesskamp, Joachim Melbert, Thomas Musch
Abstract Battery aging is a main concern within hybrid and electrical cars. Determining the current state-of-health (SOH) of the battery on board of a vehicle is still a challenging task. Electrochemical Impedance Spectroscopy (EIS) is an established laboratory method for the characterization of electrochemical energy storages such as Lithium-Ion (Li-Ion) cells. EIS provides a lot of information about electrochemical processes and their change due to aging. Therefore it can be used to estimate the current SOH of a cell. Standard EIS methods require the excitation of the cell with a certain waveform for obtaining the impedance spectrum. This waveform can be a series of monofrequent sinusoidal signals or a time-domain current pulse with a dedicated Fourier spectrum. However, any form of dedicated perturbation is not generally applicable on board of an electric vehicle.
2015-04-14
Journal Article
2015-01-0906
Xin Yu, Xi Luo, Marcis Jansons, Doohyun Kim, Jason Martz, Angela Violi
Abstract An experimental fuel surrogate validation approach is proposed for a compression ignition application, and applied to validate a Jet-A POSF 4658 fuel surrogate. The approach examines the agreement of both physical and chemical properties of surrogate and target fuels during validation within a real compression-ignition engine environment during four sequential but distinct combustion phases. In-cylinder Mie Scattering measurements are applied to evaporating sprays to compare the behavior of the surrogate, its target fuel, and for reference, n-heptane. Early mixture formation and low temperature reaction behavior were investigated using 2-D broadband chemiluminescence imaging, while high temperature ignition and combustion chemistry were studied using OH chemiluminescence imaging. The optical measurements were combined with cylinder pressure-based combustion analysis, including ignition delay and premixed burn duration, to validate the global behavior of the surrogate.
2015-04-14
Journal Article
2015-01-0952
Michael A. Groendyk, David Rothamer
Abstract The effect of fuel physical properties on the ignition and combustion characteristics of diesel fuels was investigated in a heavy-duty 2.52 L single-cylinder engine. Two binary component fuels, one comprised of farnesane (FAR) and 2,2,4,4,6,8,8-heptamethylnonane (HMN), and another comprised of primary reference fuels (PRF) for the octane rating scale (i.e. n-heptane and 2,2,4-trimethylpentane), were blended to match the cetane number (CN) of a 45 CN diesel fuel. The binary mixtures were used neat, and blended at 25, 50, and 75% by volume with the baseline diesel. Ignition delay (ID) for each blend was measured under identical operating conditions. A single injection was used, with injection timing varied from −12.5 to 2.5 CAD. Injection pressures of 50, 100, and 150 MPa were tested. Observed IDs were consistent with previous work done under similar conditions with diesel fuels. The shortest IDs were seen at injection timings of −7.5 CAD.
2015-04-14
Technical Paper
2015-01-0463
Kasiraja Thangapandian, Immanuel Rajkumar
Abstract In recent years the automotive industry is facing unprecedented influx of new technology advancements and ever-increasing consumer demands for media, entertainment and connectivity applications. This drives the automotive industry to deliver the products at a faster pace, thereby reducing time to market which results in issues from end users and dealers. Automotive industries are striving hard to keep pace with these radical changes with increase in software and electronics which in turn necessitates a systematic and effective software engineering approach to deliver high quality product from the core embedded software industry. This paper details how embedded software projects are developed globally and customer issues are collected and analyzed. It also discuss about the method used for performing effective Root cause analysis for identifying the systemic issues and formulating the systemic improvement actions.
2015-04-14
Technical Paper
2015-01-0202
Armin Wasicek, Andre Weimerskirch
Abstract Combatting the modification of automotive control systems is a current and future challenge for OEMs and suppliers. ‘Chip-tuning’ is a manifestation of manipulation of a vehicle's original setup and calibration. With the increase in automotive functions implemented in software and corresponding business models, chip tuning will become a major concern. Recognizing and reporting of tuned control units in a vehicle is required for technical as well as legal reasons. This work approaches the problem by capturing the behavior of relevant control units within a machine learning system called a recognition module. The recognition module continuously monitors vehicle's sensor data. It comprises a set of classifiers that have been trained on the intended behavior of a control unit before the vehicle is delivered. When the vehicle is on the road, the recognition module uses the classifier together with current data to ascertain that the behavior of the vehicle is as intended.
2015-04-14
Technical Paper
2015-01-0204
Biswajit Panja, Lars Wolleschensky
Abstract In this paper we propose a secure wireless sensor network system for vehicle health monitoring (VHM). We discuss the architecture of the proposed model, and it's implementation in vehicles. Modified AES-CCM is used to provide confidentiality in the network. In the proposed scheme combination of interactive and non-interactive methods are used for reliable message delivery.
2015-04-14
Technical Paper
2015-01-0280
Falco K. Bapp, Oliver Sander, Timo Sandmann, Viet Vu Duy, Steffen Baehr, Juergen Becker
Abstract Multicores, being the latest state-of-the-art technology, gain more and more importance in automotive and aerospace systems. This technology will not only be used in infotainment and non-safety-critical applications but will also be introduced in upcoming safety-critical systems. At the moment, various commercial off-the-shelf processors are available that are, however, not built for such applications. In order to ensure correct system behavior, online monitoring can be used for processors targeting infotainment or general purpose applications. The cores and other bus masters within the MPSoC compete for the exclusive use of shared resources like a memory controller. It is of high importance to provide guarantees of usage in such cases, e.g. in terms of access time and rates.
2015-04-14
Technical Paper
2015-01-0304
Samveg Saxena, Jason MacDonald, Doug Black, Sila Kiliccote
Abstract Electric vehicles (EVs) enable improved vehicle efficiency and zero emissions in population centers, however the large loads from EV charging can stress grid systems during periods of peak demand. We apply detailed physics-based models of EVs with data on how drivers use their cars to quantify the ability for EVs to reduce their charging during periods of peak demand, i.e. as in a demand response program. A managed charging controller is developed and applied within the vehicle-to-grid simulator (V2G-Sim) which charges vehicles during demand response (DR) events only if charging is required to satisfy anticipated mobility needs for a given driver over the next 24 hours. We find that up to 95% of EV charging loads can be removed during DR events without compromising the mobility needs of individual drivers. This value is found by comparing the charging loads of EVs using the managed charging controller against an uncontrolled charging case.
2015-04-14
Journal Article
2015-01-1209
Zhengyu Liu, Thomas Winter, Michael Schier
Abstract This paper presents the development of a novel direct coil cooling approach which can enable high performance for electric traction motor, and in further significantly reduce motor losses. The proposed approach focuses on bypassing critical thermal resistances in motor by cooling coils directly in stator slots with oil flow. Firstly, the basic configuration and features are shown: sealed stator slots to air gap, pressure reservoirs on both side of the slots and slot channels for oil flow. The key to enhance thermal performance of the motor here is based on introducing fluid guiding structure in the slot channels. Next, heat transfer in the channel with guiding structure is investigated by CFD and compared with bare slot channel without guiding structure. For studying the effectiveness of proposed cooling concept, numerical analysis is conducted to compare it with HEV favored oil impingement cooling.
2015-04-14
Journal Article
2015-01-1680
David H. Myszka, Andrew Murray, Kevin Giaier, Vijay Krishna Jayaprakash, Christoph Gillum
Regenerative brake and launch assist (RBLA) systems are used to capture kinetic energy while a vehicle decelerates and subsequently use that stored energy to assist propulsion. Commercially available hybrid vehicles use generators, batteries and motors to electrically implement RBLA systems. Substantial increases in vehicle efficiency have been widely cited. This paper presents the development of a mechanical RBLA that stores energy in an elastic medium. An open differential is coupled with a variable transmission to store and release energy to an axle that principally rotates in a single direction. The concept applies regenerative braking technology to conventional automobiles equipped with only an internal combustion engine where the electrical systems of hybrid vehicles are not available. Governing performance equations are formulated and design parameters are selected based on an optimization of the vehicle operation over a simulated urban driving cycle.
2015-04-14
Technical Paper
2015-01-0160
Ingo Stürmer, Elke Salecker
Model-based software development is a well-established software development process and recognized by ISO26262 [1] as allowing for highly consistent and efficient development. Nevertheless, enhancing a model-based development process in such a way that it is compliant with the ISO26262 safety standard is a challenging task. To achieve ISO26262 compliance, the development team of a safety-related software project faces a multitude of additional requirements for the development process without a corresponding increase of the project budget to fulfill them. The fact that many of the requirements of ISO26262 are defined in a very generic way such that an interpretation is required further hampers their implementation. We propose a 10-step strategy to achieve an ISO26262 compliant model-based software development process. This strategy relates ISO26262 requirements with state-of-the art methods and approaches currently used for model-based software development.
2015-04-14
Technical Paper
2015-01-0265
Martin Krammer, Philip Stirgwolt, Helmut Martin
Abstract The standard ISO 26262 stipulates a “top-down” approach based on the process “V” model, by conducting a hazard analysis and risk assessment to determine the safety goals, and subsequently derives the safety requirements down to the appropriate element level. The specification of safety goals is targeted towards identified hazardous events, whereas the classification of safety requirements does not always turn out non-ambiguous. While requirement formalization turns out to be advantageous, the translation from natural language to semi-formal requirements, especially in context of ISO 26262, poses a problem. In this publication, a new approach for the formalization of safety requirements is introduced, targeting the demands of safety standard ISO 26262. Its part 8, clause 6 (“Specification and management of safety requirements”) has no dedicated work product to accomplish this challenging task.
2015-04-14
Technical Paper
2015-01-0271
Fabian Joerg Uwe Koark, Christian Beul
Abstract Functional Safety engineering aligned to an international standard is already a long-lasting discussion. Nevertheless, the requirements of process conformance to assure functional safety have been detailed in description and interpretation. The ISO 26262 is seen as state-of-the-art Functional Safety engineering basement in Europe, the closer interpretation of the IEC 61508 is claimed by assessors in America and Asia. This work shows how stagnation in engineering process improvement is solved by re-engineering projects. The benefits of re-engineering are described in this context. A four month, proven-in-practice project plan is explained. The expected results of such a project are given as generic goals for similar projects. A practice report shows the realistic outcome of such a project for the Chinese automotive industry. The report shows how the motivation of the involved engineers was gained and how existing engineering documentation was used in an efficient way.
2015-04-14
Technical Paper
2015-01-0273
Helmut Martin, Martin Krammer, Bernhard Winkler, Christian Schwarzl
Abstract Although the ISO 26262 provides requirements and recommendations for an automotive functional safety lifecycle, practical guidance on how to handle these safety activities and safety artifacts is still lacking. This paper provides an overview of a semi-formal safety engineering approach based on SysML for specifying the relevant safety artifacts in the concept phase. Using specific diagram types, different views of the available data can be provided that reflects the specific needs of the stakeholders involved. One objective of this work is to improve the common understanding of the relevant safety aspects during the system design. The approach, which is demonstrated here from the perspective of a Tier1 supplier for an automotive battery system, covers different breakdown levels of a vehicle. The safety workflow presented here supports engineers' efforts to meet the safety standard ISO 26262 in a systematic way.
2015-04-14
Technical Paper
2015-01-0278
Ingo Stürmer, Heiko Doerr, Thomas End
Managing ISO 26262 software development projects is a challenging task. This paper discusses major challenges in managing safety-critical projects from a high-level perspective, i.e. from a manager's point of view. We address managers (directors) with full project responsibility including software and hardware teams. Rather than discussing how to fulfill (technical) requirements stated by the ISO standard, we highlight major challenges and tough decisions a manager has to face on her way from project start up to delivery of the safety case. We discuss important project management topics and best practices such as negotiation issues with the contractor (OEM), selection of the appropriate functional safety manager, general ISO 262626-related project management matters, as well as contractual issues with supplier such as development interface agreement. We discuss the topics on the basis of real-life experience we collected during several ISO 26262 management projects.
2015-04-14
Technical Paper
2015-01-1638
Dejan Kihas, Michael R. Uchanski
Recently, numerous researchers and Original Equipment Manufacturers (OEMs) have developed diesel engine-out nitrogen oxides (NOx) estimation algorithms that are capable of running in real-time on production Electronic Control Units (ECUs). These are generally referred to as virtual sensors or inferential sensors. NOx estimators are typically installed to improve On-Board Diagnostics (OBD) monitors or to lower bill of material costs by replacing physical NOx sensors. This paper reviews the literature of on-ECU NOx models in order to document the state of the art and identify directions for future work. The discussion includes applications of NOx estimators, accuracy of NOx estimators, required sensor inputs, sources of error, calibration effort, and ECU resource consumption.
2015-04-14
Technical Paper
2015-01-0926
Tianyun Li, Min Xu, David Hung, Shengqi Wu, Siqi Cheng
Abstract Comparing with port-fuel-injection (PFI) engine, the fuel sprays in spark-ignition direct-injection (SIDI) engines play more important roles since they significantly influence the combustion stability, engine efficiency as well as emission formations. In order to design higher efficiency and cleaner engines, further research is needed to understand and optimize the fuel spray atomization and vaporization. This paper investigates the atomization and evaporation of n-pentane, gasoline and surrogate fuels sprays under realistic SIDI engine conditions. An optical diagnostic technique combining high-speed Mie scattering and Schlieren imaging has been applied to study the characteristics of liquid and vapor phases inside a constant volume chamber under various operating conditions. The effects of ambient temperature, fuel temperature, and fuel type on spray atomization and vaporization are analyzed by quantitative comparisons of spray characteristics.
2015-04-14
Technical Paper
2015-01-0938
Prashanth Karra, Thomas Rogers, Petros Lappas
Abstract The air entrainment process of a compressed natural gas transient fuel jet was investigated in a constant-volume chamber using Schlieren and particle image velocimetry (PIV) techniques. A new method of calculating air entrainment around a gaseous fuel jet is proposed using Schlieren and PIV imaging techniques. This method offers an alternative to calculation of an alternative to calculation of entrainment using LIF technique in gaseous fuel jets. Several Jet-ambient pressure ratios were tested. In each test, nitrogen was used to fill the chamber as an air surrogate before the jet of natural gas was injected. Schlieren high speed videography and PIV experiments were performed at the same conditions. Schlieren mask images were used to accurately identify the jet boundary which was then superimposed onto a PIV image. Vectors adjacent to the Schlieren mask in the PIV image were used to calculate the spatial distribution of the air entrainment at the jet boundary.
2015-04-14
Technical Paper
2015-01-1382
Lisa Schei Blikeng, Siril Hegén Agerup
Abstract This paper is based on the bachelor thesis “Fire in electric cars” [1] 2013, written in Norwegian. The number of electric vehicles has increased significantly in recent years. Today, there are more than 35,000 electric cars in Norway, and the government's goal is 200,000 cars by 2020. [3] The main question investigated was: What happens when the lithium-ion battery pack ignites? The major part of this assignment was to perform a full-scale fire experiment with a modern and drivable electric car. This experiment took place in February 2013, when a Peugeot iOn 2012 model was set on fire. The car burned out without any attempt being made to extinguish the fire. We had to supply much heat from the external heat source to achieve thermal runaway in the cells. Observations and results from the experiment indicated that fire in the lithium-ion battery cells consists of two phases.
2015-04-14
Technical Paper
2015-01-1450
Jeremy Daily, Andrew Kongs, James Johnson, Jose Corcega
Abstract The proper investigation of crashes involving commercial vehicles is critical for fairly assessing liability and damages, if they exist. In addition to traditional physics based approaches, the digital records stored within heavy vehicle electronic control modules (ECMs) are useful in determining the events leading to a crash. Traditional methods of extracting digital data use proprietary diagnostic and maintenance software and require a functioning ECM. However, some crashes induce damage that renders the ECM inoperable, even though it may still contain data. As such, the objective of this research is to examine the digital record in an ECM and understand its meaning. The research was performed on a Detroit Diesel DDEC V engine control module. The data extracted from the flash memory chips include: Last Stop Record, two Hard Brake events, and the Daily Engine Usage Log. The procedure of extracting and reading the memory chips is explained.
2015-04-14
Technical Paper
2015-01-0203
Brian Anderson, Mark Brooks, Ryan Wilson, Purser K. Sturgeon II
Several wireless systems such as Dedicated Short Range Communication (DSRC), cellular, Wi-Fi, Bluetooth, and the Tire Pressure Monitoring System (TPMS) can be found on modern vehicles. In the future, Software Defined Radio (SDR) technology could be integrated into automobiles to increase the efficiency and adaptability of wireless communications systems. SDR is also a powerful tool for designing and testing new communications protocols. However there are also some security considerations associated with SDR. This paper will review some advantages of using SDR technology in the automotive domain as well as potential security issues. The authors are currently conducting research into the use of SDR technology to model wireless systems and investigate security threats in modern vehicular systems.
2015-04-14
Technical Paper
2015-01-0274
John Thomas, John Sgueglia, Dajiang Suo, Nancy Leveson, Mark Vernacchia, Padma Sundaram
Abstract The introduction of new safety critical features using software-intensive systems presents a growing challenge to hazard analysis and requirements development. These systems are rich in feature content and can interact with other vehicle systems in complex ways, making the early development of proper requirements critical. Catching potential problems as early as possible is essential because the cost increases exponentially the longer problems remain undetected. However, in practice these problems are often subtle and can remain undetected until integration, testing, production, or even later, when the cost of fixing them is the highest. In this paper, a new technique is demonstrated to perform a hazard analysis in parallel with system and requirements development. The proposed model-based technique begins during early development when design uncertainty is highest and is refined iteratively as development progresses to drive the requirements and necessary design features.
2015-04-14
Journal Article
2015-01-1160
Namdoo Kim, Ayman Moawad, Neeraj Shidore, Aymeric Rousseau
Abstract Plug-in Hybrid Electric Vehicles (PHEVs) have demonstrated the potential to provide significant reduction in fuel use across a wide range of dynamometer test driving cycles. Companies and research organizations are involved in numerous research activities related to PHEVs. One of the current unknowns is the impact of driving behavior and standard test procedure on the true benefits of PHEVs from a worldwide perspective. To address this issue, five different PHEV powertrain configurations (input split, parallel, series, series-output split and series-parallel), implemented on vehicles with different all-electric ranges (AERs), were analyzed on three different standard cycles (i.e., Urban Dynamometer Driving Schedule, Highway Fuel Economy Test, and New European Driving Cycle). Component sizes, manufacturing cost, and fuel consumption were analyzed for a midsize car in model year 2020 through the use of vehicle system simulations.
2015-04-14
Technical Paper
2015-01-0309
Mayurika Chatterjee, Atchyuta Rao, Chaitanya Rajguru
Abstract Parking assist systems have become very common in current vehicles. The purpose of such a system is to assist the driver to park the vehicle without collision. The sensors serve as eyes of the driver during parking maneuver by sensing any obstacle in the path. The parking sensors, typically ultrasonic sensors, are mounted on front and rear of vehicle to assist the driver to park the vehicle. Thus, such a system can cover only the front and rear portion of the vehicle and is unable to cover the side portions of the vehicle. This paper proposes a novel method to monitor the perimeter of a vehicle while parking using minimum sensors placed at strategic locations. A local map of the parking area is generated using data from sensors which helps in identifying static obstacles. The map is constantly updated in real time during parking. The algorithm ascertains that the entire perimeter of the vehicle is protected from impending collisions in real time.
2015-04-14
Technical Paper
2015-01-0310
R Danymol, Krishnan Kutty
Abstract Camera sensors that are made of silicon photodiodes and used in ordinary digital cameras are sensitive to visible as well as Near-Infrared (NIR) wavelength. However, since the human vision is sensitive only in the visible region, a hot mirror/infrared blocking filter is used in cameras. Certain complimentary attributes of NIR data are, therefore, lost in this process of image acquisition. However, RGB and NIR images are captured entirely in two different spectra/wavelengths; thus they retain different information. Since NIR and RGB images compromise complimentary information, we believe that this can be exploited for extracting better features, localization of objects of interest and in multi-modal fusion. In this paper, an attempt is made to estimate the NIR image from a given optical image. Using a normal optical camera and based on the compressed sensing framework, the NIR data estimation is formulated as an image recovery problem.
2015-04-14
Technical Paper
2015-01-0307
Hongfeng Wang, Lei He, Qianfei Liu, Changfu Zong
Abstract Nowadays active collision avoidance has become a major focus of research, and a variety of detection and tracking methods of obstacles in front of host vehicle have been applied to it. In this paper, laser radars are chosen as sensors to obtain relevant information, after which an algorithm used to detect and track vehicles in front is provided. The algorithm determines radar's ROI (Region of Interest), then uses a laser radar to scan the 2D space so as to obtain the information of the position and the distance of the targets which could be determined as obstacles. The information obtained will be filtered and then be transformed into cartesian coordinates, after that the coordinate point will be clustered so that the profile of the targets can be determined. A threshold will be set to judge whether the targets are obstacles or not. Last Kalman filter will be used for target tracking. To verify the presented algorithm, related experiments have been designed and carried out.
2015-04-14
Technical Paper
2015-01-0217
William Buller, Rini Sherony, Brian Wilson, Michelle Wienert
Abstract To reduce the number and severity of accidents, automakers have invested in active safety systems to detect and track neighboring vehicles to prevent accidents. These systems often employ RADAR and LIDAR, which are not degraded by low lighting conditions. In this research effort, reflections from deer were measured using two sensors often employed in automotive active safety systems. Based on a total estimate of one million deer-vehicle collisions per year in the United States, the estimated cost is calculated to be $8,388,000,000 [1]. The majority of crashes occurs at dawn and dusk in the Fall and Spring [2]. The data includes tens of thousands of RADAR and LIDAR measurements of white-tail deer. The RADAR operates from 76.2 to 76.8 GHz. The LIDAR is a time-of-flight device operating at 905 nm. The measurements capture the deer in many aspects: standing alone, feeding, walking, running, does with fawns, deer grooming each other and gathered in large groups.
2015-04-14
Technical Paper
2015-01-0493
Ying Wang, Ye Wang, You Qu, Sumin Zhang, Weiwen Deng
Abstract Vision-based Advanced Driver Assistance Systems has achieved rapid growth in recent years. Since vehicle field testing under various driving scenarios can be costly, tedious, unrepeatable, and often dangerous, simulation has thus become an effective means that reduces or partially replaces the conventional field testing in the early development stage. However, most of the commercial tools are lack of elaborate lens/sensor models for the vehicle mounted cameras. This paper presents the system-based camera modeling method integrated virtual environment for vision-based ADAS design, development and testing. We present how to simulate two types of cameras with virtual 3D models and graphic render: Pinhole camera and Fisheye camera. We also give out an application named Envelope based on pinhole camera model which refers to the coverage of Field-of-Views (FOVs) of one or more cameras projected to a specific plane.
2015-04-14
Technical Paper
2015-01-1384
Richard Young, Jing Zhang
Abstract In this age of the Internet of Things, people expect in-vehicle interfaces to work just like a smartphone. Our understanding of the reality of in-vehicle interfaces is quite contrary to that. We review the fundamental principles and metrics for automotive visual-manual driver distraction guidelines. We note the rise in portable device usage in vehicles, and debunk the myth of increased crash risk when conversing on a wireless device. We advocate that portable electronic device makers such as Apple and Google should adopt driver distraction guidelines for application developers (whether for tethered or untethered device use in the vehicle). We present two design implications relevant to safe driving. First, the Rule of Platform Appropriateness: design with basic principles of ergonomics, and with driver's limited visual, manual and cognitive capacity, in mind. Second, the Rule of Simplicity: thoughtful reduction in the complexity of in-vehicle interfaces.
2015-04-14
Journal Article
2015-01-0621
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Abstract There is an increasing customer demand for adjustable chassis control features which enable adaption of the vehicle comfort and driving characteristics to the customer requirements. One of the most promising vehicle control systems which can be used to change the vehicle characteristics during the drive is the semi-active suspension system. This paper presents a Rule-Optimized Fuzzy Logic controller for semi-active suspension systems which can continuously adjust itself not only according to the road conditions but also to the driver requirements. The proposed controller offers three different control modes (Comfort, Normal and Sport) which can be switched by the driver during driving. The Comfort Mode minimizes the accelerations imposed on the driver and passengers by using a softer damping. On the other hand, the increased damping in Sport Mode provides better road holding capability, which is critical for sporty handling.
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