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Safety-Critical Systems, 2017

2017-03-28
The papers in this colleciton focus on system safety analysis and design of safety-critical systems employing electronic controls. Topics include: implementation of safety-relevant systems, fail-safe strategies, distributed fault tolerant systems and hazard analysis. Application areas include: automotive active safety and alternative energy systems as well as avionics and mission management.
Technical Paper

Integration and Validation of Sheet Metal Forming Simulation Computer Programs Into the Design Process

1996-04-01
91A121
In order to improve the design of drawn parts and to reduce the number of trial and error tests, Renault has undertaken the development and the validation of various finite element procedures and codes. This paper describes the function of each software and its level of integration into the design process. One of them is already an operational tool used be planners whilst the others are still in the validation phase. Selected examples show typical applications of the computer programs on automotive parts.
Technical Paper

The Prediction of Shrinkage and Warpage in Plastics Injection Molded Auto Parts

1996-04-01
91A088
The article emphasizes the effect of flow on dimensional stability, mechanical properties and surface finish, and the close coupling of dimensional stability and mechanical properties. Warpage is the result of the balance between the structural stiffness of the part and the stress pattern resulting in variation in shrinkage due to area shrinkage, orientation, and thermal effects. The practical solution to warpage depends on the use of software to isolate the basic causes of warping which then leads to a logical solution procedure.
Technical Paper

A Driving Simulator Using Microprocessors

1988-03-01
871156
An inexpensive driving simulation system with sufficient fidelity has been developed. The system produces motion cues of four degrees of freedom, visual and auditory cues, and control feel on the steering wheel. This paper describes the features of this newly developed system and gives examples that demonstrate its effectiveness. The motion cues provided in this system are yaw, heave, and lateral and fore/aft accelerations. The lateral and fore/aft accelerations are simulated by tilting the simulator compartment. A computer-processed road image is given through a CRT monitor. The restoring torque of the steering wheel is produced by an electrical servosystem via a coil spring. Cruising sound is given in order to improve speed perception. Since the system uses digital computers, the vehicle characteristics are altered easily by merely rewriting the software. This enables us to simulate special vehicle dynamics such as front & rear wheel steering.
Technical Paper

Use of Statistical Energy Analysis Method to Predict Sound Transmission Loss of Sound Barrier Assemblies

1999-05-17
1999-01-1707
Statistical Energy Analysis (SEA) method is used to predict Sound Transmission Loss (STL) of sound barrier assemblies (SBA) commonly used in automotive dashmat design. Tests are performed for dashmat plaques with and without design features, and SEA equations have been used for predicting transmission loss with acceptable accuracy below the interception (cavity resonance) frequency. For frequency range higher than interception point, the SEA software used overestimates STL. For dashmat tests with design features, test results and SEA predictions are generally agreeable.
Technical Paper

Design and Implementation of a Damping Material Measurement / Design System

1999-05-17
1999-01-1675
A hardware / software package is presented that is used to determine the dynamic mechanical properties of viscoelastic materials as a function of temperature and frequency. The material properties can then be used to aid in the design of surface damping treatments for various engineering structures.
Technical Paper

Human Centered Manufacturing: a Necessity for Enhancing Productivity and Competitiveness

1999-04-20
1999-01-1605
This paper argues in favor of a human-centered (anthropocentric) approach to modern manufacturing. The bases for these arguments are: (a) worker deskilling and creativity issues, (b) economics, and (c) unresolved problems in automation, such as software reliance and costs. Detailed arguments are avoided owing to space limitations. Finally, some issues confronting human-centered manufacturing are raised.
Technical Paper

Spin Resistance Development for Small Airplanes - A Retrospective

2000-05-09
2000-01-1691
With the resurgence of the General Aviation industry, the incentive to develop new airplanes for the low-end market has increased. Increased production of small airplanes provides the designers and manufacturers the opportunity to incorporate advanced technologies that are not readily retrofitable to existing designs. Spin resistance is one such technology whose development was concluded by NASA during the 1980’s when the production of small airplanes had slipped into near extinction. This paper reviews the development of spin resistance technology for small airplanes with emphasis on wing design. The definition of what constitutes spin resistance and the resulting amendment of the Federal Aviation Regulations Part 23 to enable certification of spin resistant airplanes are also covered.
Technical Paper

Development of a Sensor-Less Speed Control Inverter for an Automotive Accessory Permanent Magnet Motor

2000-04-02
2000-01-1605
Visual Computing Systems (VCS) and Oak Ridge National Laboratory (ORNL) are partnered in a research effort to design and build a power inverter for use with an automotive accessory permanent magnet (PM) motor provided by VCS. The inverter is designed so it can fit within the volume of the housing, which is integrated with the motor. Moreover, a modular design for both the inverter and motor is employed for easily expanding the power capability to other applications. A simple back electromotive force (EMF) based position detection scheme is implemented with a digital signal processor (DSP) to eliminate the need for position sensors. Issues related to position detection errors are addressed and correction methods are suggested and implemented in DSP software. Finally, since the motor has very low inductance because of its core-less stator structure, the influences of the low inductance on the motor current ripple are analyzed.
Technical Paper

Advanced Automotive Technologies Energy Storage R&D Programs at the U.S. Department of Energy-Recent Achievements and Current Status

2000-04-02
2000-01-1604
The United States supports an active research and development (R&D) program to develop electric and hybrid vehicle technologies and accelerate their commercialization. The U.S. Department of Energy (DOE), through its Office of Advanced Automotive Technologies (OAAT), supports the development of advanced energy storage and power electronics technologies, fuel cells, advanced direct-injection engines, vehicle systems, lightweight materials, and fuels. Much of this R&D directly supports the Partnership for a New Generation of Vehicles (PNGV), a landmark partnership between the U.S. Federal Government and automakers with the goal of developing a six-passenger family sedan with up to 80 miles per gallon (mpg) fuel economy by 2004. In these efforts, the DOE is working closely with its national laboratories, the auto industry and its suppliers, other government agencies, universities, and innovative small businesses. The Department continues to collaborate closely with the U.S.
Technical Paper

Review of Organic Friction Modifiers - Contribution to Fuel Efficiency?

2000-06-19
2000-01-1792
Friction modifiers have been around for many years. Originally, the application was for limited slip gear oils, automatic transmission fluids and multipurpose tractor fluids. Since fuel economy became an international issue, initially to reduce crude oil consumption, friction modifiers have been introduced into automotive crankcase lubricants as well. The current emphasis is to improve the fuel efficiency through the engine lubricant and to reduce emissions to the environment. This paper describes the chemistry of the various organic friction modifiers as well as the non-organic types. A basic understanding is given on the mechanisms how and why these products work as friction modifiers and what is known about structure - activity relationships. Definitions are given about the various lubrication regimes as well as figures to what extend these regimes are present in current engine tests measuring fuel economy.
Technical Paper

Rheology of Used Diesel Lubricants When Contaminated with Soot - The Brookfield Measurement Opportunity

2000-06-19
2000-01-1808
Used Diesel oil viscosity is commonly measured by the kinematic method as outlined in the Mack T-8 used diesel soot procedure (ASTM D 5967 for used oil from Mack T-8 engine test, and CEC L-83-A-97 for used oil from PSA XUD11 ATE engine test). The limitations of the kinematic viscosity measurement for used oils heavily loaded with carbonaceous matters, have led to a new proposed method which may be better suited for these oils. This paper describes an investigation about the rheology of Diesel oils heavily loaded with carbonaceous matters. The kinematic viscosity result (measured with only the first sphere) was presented as a function of shear rate (imposed by differents kinematic viscometers) and demonstrated that the behaviour of these oils is not newtonian for low shear rates.
Technical Paper

System Integration and Analysis in a Virtual Prototype Environment

1999-11-15
1999-01-3712
The design and analysis of vehicle wire harnesses presents a daunting challenge to the modern day transportation industry. The continual increase in on-board vehicle electronics, driven by both consumer and legislative demands, is causing an exponential increase in wire harness complexity. To meet these challenges, software tools have been developed to assist harness designer the various tasks from system partitioning to signal integrity analysis. This paper will explore how the SaberHarness™ tool suite can be used as a virtual prototype environment for a complete system design and analysis including wire harness interconnectivity.
Technical Paper

Standardizing Documentation for Standard Products: Creating Re-Usable FMEAs by Means of Generic Structures Based on Functional Groups

1999-11-15
1999-01-3711
Re-use of FMEA data and associated QS-9000 and APQP documentation is not only appropriate, but also efficient. Computerized document management systems allow for making changes quickly and easily throughout all affected documents and facilitate the recycling of documentation for future generations of design. Using IQ-FMEA quality software, this paper will demonstrate effective and efficient techniques for structured data re-use by means of a strategy of functionally-motivated generic structure templates.
Technical Paper

Electronic Compressor and Air Dryer Control

1999-11-15
1999-01-3771
The paper details opportunities for electronic control of the pneumatic charging system of an air braked vehicle. Electronic control of the charging and drying functions can result in increased fuel efficiency and improved air quality. Control functions can be used to identify and warn of in-service issues, provide prioritized system charging for faster drive-away, and signal required preventative maintenance. The first portion of the paper describes current industry practice, as well as common issues that can result from those practices. This is followed by presentation of areas of improvement, where specialized control features result in energy savings, air quality increases and maintenance/downtime savings. This portion will focus on adaptive control of components used today, and will briefly discuss opportunities for the next generation of charging system devices. The final section of the paper presents the control logic and vehicle interface allowing for system integration.
Technical Paper

Standards for Vehicle to Office Data Communication

1999-11-15
1999-01-3755
Modern trucking companies are finding mobile data communication to be significant for operating fleets cost effectively in a competitive environment. Today's systems pass both business data and vehicle technical data between the vehicle and the business office. The communications companies which created these innovations have done so with proprietary designs, as, of course, is necessary when new technology is developed. However, as the diversity of applications expands and the market matures, the need for standards becomes apparent. In this paper we will outline standards being considered by The Maintenance Council (TMC) of the American Trucking Association to allow interoperability between onboard electronics, mobile communication systems, and office software applications.
Technical Paper

Applying Design of Experiments, Accelerated Testing and Weibull Analysis Methods to Improve ABS ECU Reliability

1999-11-15
1999-01-3763
This paper presents, in a case study format, a methodology for combining the methods of Design of Experiments, Accelerated Testing, and Weibull Analysis to improve the reliability of an ABS Electronics Control Unit (ECU). While much literature focuses on each method individually, sometimes it's necessary combine all of these methods to achieve product improvement. The paper walks through the steps of using an multi-environment over-stress accelerated test routine, with DOE methods to evaluate key factors, and then applying Weibull and Weibayes methods to validate the new proposal and estimate expect life improvement.
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