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The problem of vehicle stability in emergency maneuvers has attracted a lot of research effort recently. Perhaps the most effective contributions made in this area were devoted to the control of vehicle yaw rate either by active steering or differential braking control systems. Each control technique has its own limitations that make it ineffective in some particular situations. This paper introduces a combined steering and braking control strategy using a fuzzy logic inference system. The proposed controller uses the estimated coefficient of friction (μ) to organize the combined control action. Computer simulation using a comprehensive vehicle model is used to illustrate the strengths and limitations of various control strategies.

With the increasing complexity of the Crashworthiness development process in recent years, engineers are required to have a greater understanding of the mechanisms which lead to injury of the occupants. As both tests and simulations become more complex, the volume of data increases. The average channel count has increased by three times, the number of camera positions doubled and the number of tests conducted has been increased fourfold in the last few years. There is an ever increasing emphasis on mathematical simulations to reduce development cycle times and costs. Test and simulation are often out-sourced, requiring access to information from diverse and remote sources with minimum transfer times. Development has become a shared activity between manufacturers' teams and their suppliers, demanding common access to the same data. Large quantities of data can now be presented to engineers in a multimedia computer based format.

NHTSA's Fatal Crash Reporting System (FARS) collects information on all US fatal public roadway motor vehicle crashes.1 However, FARS contains only the information “K”(killed) as injury information for the individuals sustaining fatal injuries. This paper discusses how a 100 fold improvement in injury detail can be obtained with ICD-9 mortality information by linking FARS with the Vital Statistics Multiple Cause of Death (MCOD) database.2 This link, developed by NHTSA, is accomplished on an individual by individual basis. The FARS database contains about 40,000 individuals killed per year, and nearly 25 years of data available. A multi-year linked FARS-MCOD database can contain detailed cause of death for more than 1,000,000 motor vehicle fatalities. The linked FARS-MCOD allows the reasons why people die in MVC to be studied down to specific vehicle make/model combinations.

Today the development of modern complex automotive lighting systems is only possible with the aid of computer technology. Therefore the CAL (Computer Aided Lighting) system HELIOS was developed for own purposes. The simulation of any optical device is a main part of this program package. The light source model plays an important role in this simulation process. In general a simple model of a cylindrical light source is used, which allows a fast simulation. But sometimes it is necessary to consider more details of the lamp, because they affect important parts of the resulting light distribution. This is possible with an advanced lightsource model, which allows to build lamps like a H7 bulb with complex details.

Xenon (HID) technology is one of the mile-stones in developing process of car lighting. The first step was to combine this technology with free-form reflector technology. The result was a high performance dipped beam beam-pattern with three times more light output compared to a halogen system. The next step of improvement is “Bi-Xenon”. It makes sense to use the enormous light output of a Xenon light source for two light functions (Main beam and dipped beam) in a single pocket headlamp system. This leads to new lighting performance and design freedom in headlamp technology. In this paper the technological aspects of system realization will be described. New solutions in lighting strategy including modern actuators which handle optical elements to switch between two light functions had to be found.

A new light concept called Adaptive Light Control (ALC) is developed with the aim to improve night time traffic safety. ALC improves the headlamp illumination by means of continuous adaption of the headlamps according to the current driving situation and current environment. In order to ensure rapid prototyping and early testing the step from offline to online (real-time) simulation of light distributions in the driving simulator has been successfully done. This realtime simulation enabled the interactive development of new light distributions in different driving situations and driving environments. The solutions are directly ported to real vehicels to allow further testing with natural road conditions. In this paper, results of the development of movable headlamps are presented. These headlamps are controlled by means of path prediction based on vehicle dynamics and route vectors of the navigation system.

Today, vehicle manufacturers are continually looking for lighting improvement and styling flexibility. Therefore, headlamp systems manufacturers have to conceive and develop new designs that improve the performance and reduce volume with no significant cost increase. To reach these objectives, one of the most interesting new technologies is the Compact Lighting System. The aim of this concept is to develop a headlamp system for the two functions, Low and High beams, with only one reflector and one light source. The Compact Lighting concept provides significant volume savings and improves overall lighting performance. Moreover, the Compact Lighting concept provides HID bulb optimization by using this high performance component for both functions, High and Low beams.

In this article a hybrid driver model is described which has been developped at the Institute for Industrial Information Systems (IIIT) of the University of Karlsruhe. After a short introduction into the subject an overview over the human information perception and processing is given. A concept is presented which adapts the human behaviour to a realistic driver model. The developped driver model, which is composed of a queueing network and two GPC-controllers, is described. For the purpose of simulation three different driver types are defined and simulation results are discussed.

Scientific visualizations and computer animations are frequently presented to show the results of simulation models or the opinions of a reconstructionist. In these cases it is important to properly document the graphical images being presented. Proper documentation depends somewhat on the methodologies used to produce the images, but every scientific visualization, computer animation, and computer generated image should be documented sufficiently to allow others to duplicate the images. There are also some basic data that should accompany any computer generated images that will reveal the basis of the motion for all primary objects being depicted. This paper presents some basic definitions and outlines the data that is required to document scientific visualizations and computer animations.

HVE is a product of Engineering Dynamics Corp. designed to do scientific simulations and visualizations of vehicle accidents. It is a computer environment which combines a relational database and 3D graphics with physics programs. This paper is directed to readers who are users of HVE or are familiar with it and are considering becoming users. The purpose of this paper is to describe and discuss the types of available images and the methods for importing them into HVE. It will discuss the special considerations the authors have found necessary for the various types of images and for their incorporation into the HVE environment.

With the increased use of three-dimensional computer animations to depict the results of accident reconstructions and other engineering analyses, the need for the rapid and efficient generation of accurate computer models of geographical terrain has grown recently. This paper provides a method by which such terrain models can be generated when digital sources of terrain data are not otherwise available.

A revision of the modeling of restitution properties in the SMAC computer program and the introduction of restitution properties in the CRASH3 program have been proposed by McHenry [1], the author of M-CRASH and M-SMAC [2]. The accuracy of an accident reconstruction, which uses the proposed restitution model, is directly related to the accuracy of the crush stiffness coefficients employed. The ideal condition for determining crush stiffness coefficients for these programs requires crash tests of a vehicle structure through a wide range of impact speeds with a rigid barrier. Reports from these crash tests should contain the usual data found in NHTSA crash test reports plus rebound velocity and maximum dynamic crush. Unfortunately, such comprehensive tests are very rare. As a result, certain vehicle properties need to be generalized from the existing available crash tests. These generalized properties can then be used to calculate crush stiffness coefficients for these programs.

Aerodynamic drag of a modern car is generated mainly by underbody flows. A better understanding of these flows and of their interactions with the car underbody, may contribute to the future improvement of the car drag characteristics. This paper reports the results of a parametric study carried out in the Pininfarina wind tunnel, on a full scale simplified car model, by using the Ground Effect Simulation System built in 1995. The main aim of this study was to investigate the effect on the aerodynamic coefficients produced by important geometric changes which affect the flows under the car, in proximity of the ground, and are often difficult or impossible to be modified when tests are made on real cars. The model chosen for this research program is that defined by the SAE “Open Jet Interference Committee” as a reference model to be used for investigating wind tunnel interference and for comparison between wind tunnels. In particular it has no wheels.

This paper examines the aerodynamic behaviour of plane-walled, single-plane-expansion, underbody diffusers fitted to a wind-tunnel model of a wheel-less, simple body having automobile proportions. The measurements were performed over a moving-belt assembly in the Pilot Wind Tunnel of the National Research Council of Canada (NRC). The purposes of the investigation were: to understand the governing physics of automotive underbody diffusers operating in ground proximity, to examine the effect of moving-ground and fixed-ground simulations on the behaviour of such diffusers and on the corresponding vehicle downforce and drag, to map the performance of simple, quasi-two-dimensional diffusers when used to produce downforce or drag reduction.

An air-to-fuel ratio (A/F) modulation scheme is presented in which a linear feedback signal is generated from a heated exhaust gas oxygen (EGO) sensor. In this scheme, the engine A/F is modulated with a triangular waveform, and the mean value of the EGO output is obtained using a rolling average filter. The resulting output is linearly related to the exhaust A/F, and is used to provide closed-loop lean A/F operation following a cold start to enhance catalyst light-off and minimize vehicle exhaust emissions. Some engine-dynamometer results obtained using the method are presented.

The design of a canned ceramic oval converter, 77mm by 146.8mm, is described along with subsequent demonstration of its high temperature (1050°C) durability. A new mat deterioration phenomenon was recognized, and will be described. The mat deterioration results from sintering of the vermiculite and glass fiber structure when exposed to temperatures greater than approximately 1000°C. Due to the extremely high temperature experienced in the supporting mat of an oval converter exposed to 1050°C, an alternative mat configuration was utilized to eliminate potential mat sintering. An inner layer of non-intumescent mat (1500g/m2) was used in conjunction with an outer layer of intumescent mat (3100g/m2). The inner mat provided sufficient thermal protection to the outer intumescent mat, maintaining considerable holding pressure on the ceramic substrate. A tourniquet closure technique was developed to uniformly compress a hybrid mat system around the entire perimeter of the oval converter.

Textron Automotive has developed a new thermoplastic castable aliphatic urethane for an instrument panel with a seamless passenger side air bag on a 1998 North American vehicle. This material was developed to meet the increased temperature range demands for a top mount seamless or invisible passenger side air bag instrument panel. Traditional castable thermoplastic materials were developed to meet aesthetic requirements until the advent of passenger side air bags forced the instrument panel to become a functional component. Conventional coverstock materials cannot meet the -40°C and 120°C air bag deployment conditions that are proposed. This paper describes: the advantages of an invisible or seamless instrument panel; the new material performance requirements to meet the invisible PSIR requirements; the advantages of thermoplastic urethane (TPU) compared to current instrument panel materials.

The possibility of changes in field life requirements, elimination of PVC in Europe and the push for a totally recyclable instrument panel have been the driving factors in the automotive industry for the replacement of polyvinyl chloride, PVC with thermoplastic olefin, TPO for automotive interiors. Field life requirements for instrument panels for the North American market has risen to 10 years of desert exposure or equivalent sealed box solar exposure. The TPO developed by Delphi is one of only a few materials able to retain its physical properties and color after this harsh exposure. TPO is fully recyclable, it can be ground and re-extruded into sheet form or ground and reused as a part of an all olefin instrument panel, TPO cover stock, polypropylene foam and rigid polypropylene substrate.

Choosing the correct thermoplastic for an instrument panel application requires a thorough understanding of the environmental and performance conditions. In the case of a high speed event, such as an airbag deployment or a knee bolster intrusion, standard static tensile properties may not adequately define the material performance. The engineer needs to understand the materials sensitivity to high strain rate extremes. The subject of this paper is the enhancement of part performance through the testing and knowledge of material performance over a range of strain rates.

The manner in which instrument panels (IPs) are designed and manufactured has changed considerably over the past decade. Recent trends such as increased size and complexity and seamless airbag designs have put pressure on suppliers of engineering thermoplastics (ETP) to provide new formulations that offer improved mechanical properties for higher performance or thinner wall designs; opportunities to lower costs through components integration and reduced materials usage; and the potential for higher manufacturing productivity via faster cycle times. Materials suppliers have responded with a variety of new products, in many cases designed specifically for instrument panel applications. Several of these products are the subject of this paper and will be introduced in terms of the performance benefits they can provide to IP designers and manufacturers.