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Viewing 1 to 30 of 113
2011-04-12
Technical Paper
2011-01-0391
Quan Zheng, Bruce Church, Ken Defore
Electro-hydraulic actuation has been used widely in automatic transmission designs. With greater demand for premium shift quality of automatic transmissions, higher pressure control accuracy of the transmission electro-hydraulic control system has become one of the main factors for meeting this growing demand. This demand has been the driving force for the development of closed loop pressure controls technology. This paper presents the further research done based upon a previously developed closed loop system. The focus for this research is on the system requirements, such as solenoid driver selection and system latency handling. Both spin-stand and test vehicle setups are discussed in detail. Test results for various configurations are given.
2004-03-08
Technical Paper
2004-01-0569
Peter J. Wezenbeek, David G. Evans, David P. Sczomak, John P. Absmeier, Gerald T. Fattic
Implementation of engine turnoff at idle is desirable to gain improvements in vehicle fuel economy. There are a number of alternatives for implementation of the restarting function, including the existing cranking motor, a 12V or 36V belt-starter, a crankshaft integrated-starter-generator (ISG), and other, more complex hybrid powertrain architectures. Of these options, the 12V belt-alternator-starter (BAS) offers strong potential for fast, quiet starting at a lower system cost and complexity than higher-power 36V alternatives. Two challenges are 1) the need to accelerate a large engine to idle speed quickly, and 2) dynamic torque control during the start for smoothness. In the absence of a higher power electrical machine to accomplish these tasks, combustion-assisted starting has been studied as a potential method of aiding a 12V accessory drive belt-alternator-starter in the starting process on larger engines.
2004-03-08
Technical Paper
2004-01-0335
Madana Gopal, Ken Baron, Minoo Shah
Automotive rollover is a complex mechanical phenomenon. In order to understand the mechanism of rollover and develop any potential countermeasures for occupant protection, efficient and repeatable laboratory tests are necessary. However, these tests are not well understood and are still an active area of research interest. It is not always easy or intuitive to estimate the necessary initial and boundary conditions for such tests to assure repeatability. This task can be even more challenging when rollover is a second or third event (e.g. frontal impact followed by a rollover). In addition, often vehicle and occupant kinematics need to be estimated a-priori, first for the safe operation of the crew and equipment safety, and second for capturing and recording the event. It is important to achieve the required vehicle kinematics in an efficient manner and thus reduce repetitive tests. Mathematical modeling of the phenomenon can greatly assist in understanding such kinematics.
2004-03-08
Technical Paper
2004-01-0342
David C. Viano, Chantal S. Parenteau
This paper provides an overview of rollover crash safety, including field crash statistics, pre- and rollover dynamics, test procedures and dummy responses as well as a bibliography of pertinent literature. Based on the 2001 Traffic Safety Facts published by NHTSA, rollovers account for 10.5% of the first harmful events in fatal crashes; but, 19.5% of vehicles in fatal crashes had a rollover in the impact sequence. Based on an analysis of the 1993-2001 NASS for non-ejected occupants, 10.5% of occupants are exposed to rollovers, but these occupants experience a high proportion of AIS 3-6 injury (16.1% for belted and 23.9% for unbelted occupants). The head and thorax are the most seriously injured body regions in rollovers. This paper also describes a research program aimed at defining rollover sensing requirements to activate belt pretensioners, roof-rail airbags and convertible pop-up rollbars.
2004-03-08
Technical Paper
2004-01-1373
Mingyu Wang, Thomas M. Urbank, Karma V. Sangwan
The present paper describes the system design for the Clear Vision auto defog system and the improvements made to the Integrated Dew Point and Glass Temperature (IDGT) sensor. The Clear Vision auto defog system has been implemented on a 2000 Cadillac DeVille. Preliminary validation tests demonstrate satisfactory performance.
2004-03-08
Technical Paper
2004-01-1682
Robert J. Campbell, Kaushik Rajashekara
With the requirements for reducing the emissions and improving the fuel economy, the automotive companies are developing hybrid, 42 V and fuel cell vehicles. Power electronics is an enabling technology for the development of environmental friendly vehicles, and to implement the various vehicle electrical architectures to obtain the best performance. In this paper, the requirements of the power semiconductor devices and the criteria for selecting the power devices for various types of low emission vehicles are presented. A comparative study of the most commonly used power devices is presented. A brief review of the future power devices that would enhance the performance of the automotive power conversion systems is also presented.
2004-03-08
Technical Paper
2004-01-1666
Barbara J. Czerny, Joseph G. D'Ambrosio, Paravila O. Jacob, Brian T. Murray, Padma Sundaram
In this paper, we review existing software safety standards, guidelines, and other software safety documents. Common software safety elements from these documents are identified. We then describe an adaptable software safety process for automotive safety-critical systems based on these common elements. The process specifies high-level requirements and recommended methods for satisfying the requirements. In addition, we describe how the proposed process may be integrated into a proposed system safety process, and how it may be integrated with an existing software development process.
2004-03-08
Technical Paper
2004-01-0845
Lijian (Lee) Zhang, Liang Chen, Alicia Vertiz, Rana Balci
In 2002, NHTSA statistics indicate air bag deployments saved an estimated 1,500 lives; however, reports of occupants having serious or fatal injuries during air bag deployment appear low relative to the number of accidents with air bag deployments. To avoid air bag induced injuries, a variety of occupant sensing technologies are being developed. One of the critical logic deployment challenges faced by these technologies is whether the system can accurately determine if the occupant is in a posture or a position such that air bag deployment may result in an injury. To improve accuracy, it is necessary to understand what postures the occupants are likely to assume during a ride and how often. For this purpose, Delphi Corporation has conducted a survey to solicit opinions on the posture usage rate. With 560 responses, the frequencies for 29 sitting postures for adult passengers and 13 child postures or positions were estimated.
2004-03-08
Technical Paper
2004-01-0841
Honglu Zhang, Deren Ma, Srini V. Raman
Since its invention in early 1990s, the side curtain airbag has become an important part of the occupant restraint system for side impact and rollover protection. Computer Aided Engineering (CAE) is often used to help side curtain airbag design. Because of the unique characteristics of side curtain airbag systems, the simulation of side curtain airbag systems faces different challenges in comparison to the simulation of driver and passenger airbag systems. The typical side curtain airbag CAE analysis includes, but is not limited to, cushion volume evaluation, cushion coverage review, cushion shrinkage and tension force review, deployment timing review and seam shape and location review. The commonly used uniform pressure airbag models serve the purpose in most cases.
2004-03-08
Technical Paper
2004-01-1059
Edward J. Bedner, Hsien H. Chen
This paper presents the development of coordinated control of vehicle systems, specifically for controlled brakes and controlled steering systems. By utilizing a control structure to oversee a four-wheel-steer (4WS) system and a brake-based vehicle stability enhancement (VSE) system, it is possible to achieve improvements in vehicle stability and driver workload/comfort, and to reduce compromises in vehicle handling. The coordinated control is designed to leverage the unique strengths of 4WS and VSE, and to prevent conflicts between them. Vehicle test results prove the viability of the concept.
2004-10-25
Technical Paper
2004-01-3062
Julie G. Marshaus, Nicholas L. Woulf, Kathryn M. Orgish, Glenn R. Bower
The University of Wisconsin - Madison hybrid vehicle team has designed and constructed a four-wheel drive, charge sustaining, parallel hybrid-electric sport utility vehicle for entry into the FutureTruck 2003 competition. This is a multi-year project utilizing a 2002 4.0 liter Ford Explorer as the base vehicle. Wisconsin's FutureTruck, nicknamed the ‘Moolander’, weighs 2000 kg and includes a prototype aluminum frame. The Moolander uses a high efficiency, 1.8 liter, common rail, turbo-charged, compression ignition direct injection (CIDI) engine supplying 85 kW of peak power and an AC induction motor that provides an additional 60 kW of peak power. The 145 kW hybrid drivetrain will out-accelerate the stock V6 powertrain while producing similar emissions and drastically reducing fuel consumption. The PNGV Systems Analysis Toolkit (PSAT) model predicts a Federal Testing Procedure (FTP) combined driving cycle fuel economy of 16.05 km/L (37.8 mpg).
2004-10-18
Technical Paper
2004-21-0010
Gary Abusamra, Rob Carpenter, Stephen Kiselewich
As automotive electronic control systems continue to increase in usage and complexity, the challenges for developing automotive diagnostics also increase. Reduced development cycle times, the increased significance of diagnostics for safety critical systems, and the integration of vehicle systems across multiple control systems all add to the tasks of developing diagnostics for the automobiles of today and tomorrow. Addressing automotive diagnostics now requires the Tier 1 supplier to utilize a formal diagnostic development methodology. There are also opportunities for Tier 1 suppliers to add value by developing vehicle-level supervisory diagnostic strategies, in addition to subsystem and system-level diagnostic strategies. There is also a prospect to provide strategies and tools to enhance service at the vehicle level. This paper proposes an approach for Tier 1 suppliers to address diagnostic and service issues at the component, system, and vehicle level.
2004-03-08
Technical Paper
2004-01-1421
C. Scott Nelson, David Chen, Joseph Ralph, Eric D'Herde
A RTD (resistive temperature device) high temperature sensor was developed for exhaust gas temperature measurement. Extensive modeling and optimization was used to supplement testing in development. The sensor was developed to be capable of withstanding harsh environments (-40° to 1000°C), typical of engine applications, including poisons, while maintaining high accuracy (< 0.5% drift after 500 hrs of aging at 950°C). The following sensor characteristics are presented: resistance-temperature curve, accuracy, response time, and long-term durability. In addition, a system error analysis program was developed with representative results.
2004-03-08
Technical Paper
2004-01-1627
Honglu Zhang, Srini Raman, Madana Gopal, Taeyoung Han
The interaction between the deploying airbag and the Out-Of-Position (OOP) occupants remains a challenge in occupant protection system simulations. The integration of Computational Fluid Dynamics (CFD) analysis into Finite Element (FE) airbag model is a helpful and important tool to address this challenge. Three major commercial crash simulation software packages widely used in the automotive safety industry, LS-DYNA, MADYMO and PAM-CRASH are in the process of implementing different approaches for airbag CFD simulation. In this study, an attempt was made to evaluate and compare the CFD integrated airbag models in these software packages. Specially designed tests were conducted to study and capture the pressure distribution inside a flat airbag and the test results were used for the evaluation. Strengths and limitations of each software package are discussed in this paper.
2004-03-08
Technical Paper
2004-01-1631
Deren Ma, Jennifer Matlack, Honglu Zhang, John Sparkman
Computer modeling and simulation have become one of the primary methods for development and design of automobile occupant protection systems (OPS). To ensure the accuracy and reliability of a math-based OPS design, the correlation quality assessment of mathematical models is essential for program success. In a typical industrial approach, correlation quality is assessed by comparing chart characteristics and scored based on an engineer's modeling experience and judgment. However, due to the complexity of the OPS models and their responses, a systematic approach is needed for accuracy and consistency. In this paper, a correlation grading methodology for the OPS models is presented. The grading system evaluates a wide spectrum of a computer model's performances, including kinematics, dynamic responses, and dummy injury measurements. Statistical analysis is utilized to compare the time histories of the tested and simulated dynamic responses.
2011-04-12
Journal Article
2011-01-1386
Mark Sellnau, James Sinnamon, Kevin Hoyer, Harry Husted
A single-cylinder engine was used to study the potential of a high-efficiency combustion concept called gasoline direct-injection compression-ignition (GDCI). Low temperature combustion was achieved using multiple injections, intake boost, and moderate EGR to reduce engine-out NOx and PM emissions engine for stringent emissions standards. This combustion strategy benefits from the relatively long ignition delay and high volatility of regular unleaded gasoline fuel. Tests were conducted at 6 bar IMEP - 1500 rpm using various injection strategies with low-to-moderate injection pressure. Results showed that triple injection GDCI achieved about 8 percent greater indicated thermal efficiency and about 14 percent lower specific CO2 emissions relative to diesel baseline tests on the same engine. Heat release rates and combustion noise could be controlled with a multiple-late injection strategy for controlled fuel-air stratification. Estimated heat losses were significantly reduced.
2005-04-11
Technical Paper
2005-01-1072
Zane Z. Yang, Srini V. Raman, Deren Ma
A steering wheel is an indispensable component in an automobile. Although the steering wheel was invented about one hundred years ago and its structure has since become more and more complex with numerous innovations, documented analysis on steering wheel performance is very limited. Today, a steering wheel is not only a wheel that controls where your car goes; it also plays an important role in a vehicle occupant protection system. Therefore, many requirements have to be met before a steering wheel goes into production. With the development of computational mechanics and increasing computer capability, it has become much easier to evaluate the steering wheel performance in a totally different way. Instead of running prototype tests, steering wheel designs can be modeled virtually in various scenarios using finite element analysis, thus facilitating the development cycle.
2005-04-11
Technical Paper
2005-01-0639
Gerard W. Malaczynski, David B. Miller, Steven L. Melby
The intensity of a combustion flame ionization current signal (ionsense) can be used to monitor and control combustion in individual cylinders during a cold engine start. The rapid detection of poor or absence of combustion can be used to determine fuel delivery corrections that may prevent engine stalls. With the ionsense cold start control active, no start failures were recorded even when the initially (prior to ionsense correction) commanded fueling had failed to produce a combustible mixture. This new dimension in fuel control allows for leaner cold start calibrations that would still be robust against the possible use of low volatility gasoline. Consequently, when California Phase 2 fuel is used, cold start hydrocarbon emissions could be lowered without the risk of an engine stall if the appropriate fuel is replaced with a less volatile one.
2005-04-11
Technical Paper
2005-01-0010
Paravila O. Jacob
Hydrogen is the most plentiful gas in the universe. However hydrogen never occurs naturally, always combines with other elements such as oxygen and carbon [1]. Hydrogen is the ultimate clean energy carrier once it is separated from other elements [11]. Moreover hydrogen can easily be generated from renewable energy sources. Hydrogen is also nonpolluting, and forms water as a harmless byproduct during the oxidation process. Safe practices in the production, storage, distribution, and use of hydrogen are essential components of a hydrogen economy [2]. A catastrophic failure in any hydrogen project could irreparably damage the entire transition strategy. The safety program element delineates the steps that the hydrogen, fuel cells & infrastructure technologies program shall ensure that all projects are performed in a safe manner.
2005-04-11
Technical Paper
2005-01-0786
Mohammad Tamimi, Deron Littlejohn, Mark Kopka, Gordon Seeley
A typical problem that is encountered by drivers of vehicles with manual transmissions is rollback on an incline. This occurs when the driver is trying to coordinate the release of the brake pedal with the release of the clutch pedal and application of the accelerator all at the same time. If not done in harmony, the vehicle will roll down the incline. While the Hill Hold function is a highly desirable feature in manual transmission vehicles, it also enhances the driving experience in automatic transmission vehicles equipped with hybrid powertrains. The Hill Hold feature supports the Stop and Go performance associated with a hybrid powertrain by holding the vehicle on an incline and preventing undesired motion. The objective of this paper is to describe the implementation of the Hill Hold feature using an electric and / or a hydraulic brake control system. The paper describes the moding states in implementing the Hill Hold function at various levels of design complexity.
2005-04-11
Technical Paper
2005-01-1061
Kevin O'Dea
Anti-Lock Brake Systems use hydraulic valves to control brake pressure and ultimately, wheel slip. The difference in pressure across these hydraulic valves affects their performance. The control of these valves can be improved if the pressure difference is known and the valve control altered accordingly. In practice, the delta- pressure is estimated. Estimating the wheel brake pressure introduces an error into the control structure of the system, i.e. the difference between the actual wheel brake pressure and the estimated wheel brake pressure. The effect of this error was investigated at the vehicle level via simulation, using stopping distance and vehicle yaw rate as evaluation criteria. Even with large errors in the brake pressure estimate, it was found that the vehicle performance was largely unaffected.
2005-04-11
Technical Paper
2005-01-0971
Mansour Masoudi
Segmented, Silicon-Carbide Diesel Particulate Filters appear to be automotive industry's popular choice for reducing particulate emissions of Diesel Engines, particularly for light duty platforms. Since flow resistance represents an important performance feature of a filter, it is important that reasonable prediction tools for such filters are developed for use in their development, design, applications and regeneration control. A model for predicting pressure drop of segmented filters is presented here: an existing, well-accepted pressure drop model for monolithic (non-segmented) filters is customized to one for a segmented filter using a ‘weighted number of inlet channels’ based on equivalent filtration wall area of a monolithic filter. Flow resistance data collected experimentally on segmented filters are used to demonstrate the accuracy of the new model.
2005-04-11
Technical Paper
2005-01-0785
Barbara J. Czerny, Joseph G. D'Ambrosio, Brian T. Murray, Padma Sundaram
Execution of a software safety program is an accepted best practice to help verify that potential software hazards are identified and their associated risks are mitigated. Successful execution of a software safety program involves selecting and applying effective analysis methods and tasks that are appropriate for the specific needs of the development project and that satisfy software safety program requirements. This paper describes the effective application of a set of software safety methods and tasks that satisfy software safety program requirements for many applications. A key element of this approach is a tightly coupled fault tree analysis and failure modes and effects analysis. The approach has been successfully applied to several automotive embedded control systems with positive results.
2005-04-11
Technical Paper
2005-01-0398
Aleksander Hac
In dynamic rollover tests many vehicles experience sustained body roll oscillations during a portion of road edge recovery maneuver, in which constant steering angle is maintained. In this paper, qualitative explanation of this phenomenon is given and it is analyzed using simplified models. It is found that the primary root cause of these oscillations is coupling occurring between the vehicle roll, heave and subsequently yaw modes resulting from suspension jacking forces. These forces cause vertical (heave) motions of vehicle body, which in turn affect tire normal and subsequently lateral forces, influencing yaw response of vehicle. As a result, sustained roll, heave and yaw oscillations occur during essentially a steady-state portion of maneuver. Analysis and simulations are used to assess the influence of several chassis characteristics on the self-excited oscillations. The results provide important insights, which may influence suspension design.
2005-04-11
Technical Paper
2005-01-1578
Aleksander Hac
In this paper the effects of rear brake imprecision on vehicle braking performance and yaw dynamics are investigated for a vehicle with individually controlled brake actuators. The effects of side to side brake force imbalance on vehicle yaw rate and path deviation during straight line braking and in braking in turn maneuvers are examined through analysis, simulations and vehicle testing. These effects are compared to the influences of disturbances encountered during normal driving such as side winds and bank angles of the road. The loss of brake efficiency due to imprecision in generating actuating force is evaluated for different types of vehicles and different levels of vehicle deceleration. Requirements regarding path deviation during straight line braking and braking efficiency on low friction surfaces were found to lead to the most stringent specifications for actuator accuracy in realizing the desired braking forces.
2004-03-08
Technical Paper
2004-01-1106
Sanket Amberkar, Farhad Bolourchi, Jon Demerly, Scott Millsap
Steer by Wire systems provide many benefits in terms of functionality, and at the same time present significant challenges too. Chief among them is to make sure that an acceptable steering feel is achieved. Various aspects of this subjective attribute will be defined mathematically. A control system that is architected specifically to meet these challenges is presented. Furthermore, the design is made such that it would be robust to tire and loading variations. Supporting vehicle data and model results are shown as needed.
2008-04-14
Technical Paper
2008-01-0131
Sudhakar Das
An analytical study of spray from an outwardly opening pressure swirl injector has been presented in this paper. A number of model injectors with varying design configurations have been used in this study. The outwardly opening injection process has been modeled using a modified spray breakup model presented in an earlier study. It has been observed that simulation results from the study clearly capture the mechanism by which an outwardly opening conical spray interacts with the downstream flow field. Velocity field near the tip of the injector shows that the conical streams emanating from an outwardly opening injector have the tendency to entrap air into the flow stream which is responsible for finer spray. A deviation from the optimum set of physical parameters showed a high propensity to produce large spray droplets. This study also emphasizes the importance of computational fluid dynamics (CFD) as an engineering tool to understand the complex physical processes.
2008-04-14
Journal Article
2008-01-0129
Siddharth H. D'Silva
The paper describes a new strategy for real-time sensor diagnostics that is based on the statistical correlation of various sensor signal pairs. During normal fault-free operation there is a certain correlation between the sensor signals which is lost in the event of a fault. The proposed algorithm quantifies the correlation between sensor signal pairs using real-time scalar metrics based on the Mahalanobis-distance concept. During normal operation all metrics follow a similar pattern, however in the event of a fault; metrics involving the faulty sensor would increase in proportion to the magnitude of the fault. Thus, by monitoring this pattern and using a suitable fault-signature table it is possible to isolate the faulty sensor in real-time. Preliminary simulation results suggest that the strategy can mitigate the false-alarms experienced by most model-based diagnostic algorithms due to an intrinsic ability to distinguish nonlinear vehicle behavior from actual sensor faults.
2007-10-29
Technical Paper
2007-01-4024
Bassem H. Ramadan, Philip C. Lundberg, Russell P. Richmond
This paper includes a numerical and experimental study of fluid flow in automotive catalytic converters. The numerical work involves using computational fluid dynamics (CFD) to perform three-dimensional calculations of turbulent flow in an inlet pipe, inlet cone, catalyst substrate (porous medium), outlet cone, and outlet pipe. The experimental work includes using hot-wire anemometry to measure the velocity profile at the outlet of the catalyst substrate, and pressure drop measurements across the system. Very often, the designer may have to resort to offset inlet and outlet cones, or angled inlet pipes due to space limitations. Hence, it is very difficult to achieve a good flow distribution at the inlet cross section of the catalyst substrate. Therefore, it is important to study the effect of the geometry of the catalytic converter on flow uniformity in the substrate.
2007-10-29
Technical Paper
2007-01-4072
J. Galante-Fox, P. Von Bacho, C. Notaro, J. Zizelman
A study was conducted to investigate the effects of commercial E-85 fuel properties on Port Fuel Injector (PFI) durability performance. E-85 corrosivity, not lubricity, was identified as the primary property affecting injector performance. Relatively high levels of water, chloride and organic acid contamination, detected in commercial E-85 fuels sampled in the U.S. in 2006, were the focus of the study. Analysis results and analytical techniques for determining contaminant levels in and corrosivity of commercial E-85 fuels are discussed. Studies were conducted with E-85 fuels formulated to represent worst-case field fuels. In addition to contamination with water, chloride and organic acids, fuels with various levels of a typical ethanol corrosion inhibitor were tested in the laboratory to measure the effects on E-85 corrosivity. The effects of these E-85 contaminants on injector durability performance were also evaluated.
Viewing 1 to 30 of 113

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