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The demand for improved fuel economy in both cars and trucks has emphasized the need for lighter weight components. The application of high strength steel to wheels, both rim and disc, represents a significant opportunity for the automotive industry. This paper discusses the Ranger HSLA wheel program that achieved a 9.7 lbs. per vehicle weight savings relative to a plain carbon steel wheel of the same design. It describes the Ranger wheel specifications, the material selection, the metallurgical considerations of applying HSLA to wheels, and HSLA arc and flash butt welding. The Ranger wheel design and the development of the manufacturing process is discussed, including design modifications to accommodate the lighter gage. The results demonstrate that wheels can be successfully manufactured from low sulfur 60XK HSLA steel in a conventional high volume process (stamped disc and rolled rim) to meet all wheel performance requirements and achieve a significant weight reduction.

The 2005 Ford GT high performance sports car was designed and built in keeping with the heritage of the 1960's LeMans winning GT40 while maintaining the image of the 2002 GT40 concept vehicle. This paper reviews the technical challenges in designing and building a super car in 12 months while meeting customer expectations in performance, styling, quality and regulatory requirements. A team of dedicated and performance inspired engineers and technical specialists from Ford Motor Company Special Vehicle Teams, Research and Advanced Engineering, Mayflower Vehicle Systems, Roush Industries, Lear, and Saleen Special Vehicles was assembled and tasked with designing the production 2005 vehicle in record time.

“There's nothing new under the sun,” the old proverb says. But you only have to read a magazine, scan a periodical, listen to the radio, watch television, or glance at the multitude of ads that promise that such and such product is the latest trend or has up-to-date, state-of-the-art technology, to seemingly prove the old proverb wrong. However, old proverbs become old because they withstand the test of time. In this case, a hasty judgement should be withheld. Currently, as in the past, the above holds true for car radios as well. Whether in the United States, Europe, Canada or Latin America, the public has always been susceptible to last minute technological advances. It is curious then, that as far as car radio styling is concerned, their appearance has been typically rather conservative, and that it is only recently that styling has begun to change to be more in tune with the times.

The cyclic behavior of single overlap aluminum joints joined through a number of different methods has been investigated using Alcan 5754-O, an alloy that potentially could be used in structural applications. Overlap shear tests of spot welded, clinched and riveted joints are compared on the basis of their fatigue performance. The fatigue response of the spot welded joint was the baseline to which the other fasteners were compared. Test results showed an improvement of approximately 25% for both the mechanical clinch joints and aluminum rivets in fatigue strength at 106 cycles. The most significant improvement in fatigue strength of 100% was found for the self piercing rivets at 106 cycles. The failure behavior of the various joining methods is discussed as well as the surface appearance.

Available methodologies for model bias identification are mainly regression-based approaches, such as Gaussian process, Bayesian inference-based models and so on. Accuracy and efficiency of these methodologies may degrade for characterizing the model bias when more system inputs are considered in the prediction model due to the curse of dimensionality for regression-based approaches. This paper proposes a copula-based approach for model bias identification without suffering the curse of dimensionality. The main idea is to build general statistical relationships between the model bias and the model prediction including all system inputs using copulas so that possible model bias distributions can be effectively identified at any new design configurations of the system. Two engineering case studies whose dimensionalities range from medium to high will be employed to demonstrate the effectiveness of the copula-based approach.

A cycle counting algorithm that will reduce a complex history into a series of discrete cycles is presented. The cycles determined by this technique are defined as closed stress-strain hysteresis loops of the type obtained from constant amplitude tests. Using the computer cycle counting algorithm, life predictions were made and compared with experimental results. These predictions were found to be typically within a ±3 factor of error. Also, the computer counting method was found to yield more accurate life predictions when compared to the histogram and range counting methods.

Due to magnesium alloy's poor weldability, other joining techniques such as laser assisted self-piercing rivet (LSPR) are used for joining magnesium alloys. This research investigates the fatigue performance of LSPR for magnesium alloys including AZ31 and AM60. Tensile-shear and coach peel specimens for AZ31 and AM60 were fabricated and tested for understanding joint fatigue performance. A structural stress - life (S-N) method was used to develop the fatigue parameters from load-life test results. In order to validate this approach, test results from multijoint specimens were compared with the predicted fatigue results of these specimens using the structural stress method. The fatigue results predicted using the structural stress method correlate well with the test results.

Automakers have the opportunity to utilize bio-based composite materials to lightweight cars while replacing conventional, nonrenewable resource materials. In this study, Life Cycle Assessment (LCA) is used to understand the potential benefits and tradeoffs associated with the implementation of bio-based composite materials in automotive component production. This cradle-to-grave approach quantifies the fiber and resin production as well as material processing, use, and end of life for both a conventional glass-reinforced polypropylene component as well as a cellulose-reinforced polypropylene component. The comparison is calculated for an exterior component on a high performance vehicle. The life cycle primary energy consumption and global warming potential (GWP) are evaluated. Reduced GWP associated with the alternative component are due to the use of biomass as process energy and carbon sequestration, in addition to the alternative material component's lightweighting effect.

A number of analytical tools have been used, without any significant success, in the machine manufacturing industry to predict performance of machining processes. The overall equipment efficiency numbers realized on the plant floors provide the supporting evidence of a need of considerable improvements and offer an opportunity for the development of methodologies to characterize the machining processes before installation on the plant floor. Mechanical vibrations signature analysis approach has been used to characterize machine components on the plant floor, but in a limited capacity and under idle conditions. However, attempts to establish vibration standards in machining process characterization without exercising machining loads can cause a false sense of security. This paper describes a methodology of characterizing a given machining process by considering the machine structure, tooling and spindle, workpiece fixture, and the part as the major elements of the machining process.

This paper describes the fabrication and operation of a low-cost, monolithic silicon mass-air-flow sensor (MAFS) developed for automotive applications. The device is a hot wire anemometer made of two thin single-crystal silicon beams, one being the heated element and the other serving as a temperature reference. Temperature compensation techniques and the design tradeoffs to maximize performance while ensuring durability in the harsh automotive environment are discussed.

This paper presents the application of a proposed fuzzy inference system as part of a stability control design scheme implemented with active steering actuator sets. The fuzzy inference system is used to detect the level of overseer/understeer at the high level and a speed-adaptive activation module determines whether an active front steering, active rear steering, or active 4 wheel steering is suited to improve vehicle handling stability. The resulting model-free system is capable of minimizing the amount of model calibration during the vehicle stability control development process as well as improving vehicle performance and stability over a wide range of vehicle and road conditions. A simulation study will be presented that evaluates the proposed scheme and compares the effectiveness of active front steer (AFS) and active rear steer (ARS) in enhancing the vehicle performance. Both time and frequency domain results are presented.

A new bumper system which provides 8 kph (5 mph) vehicle protection with superior quality, outstanding durability and high value is in production. The system includes five new technologies: Hot stamped, ultra high strength front beam, 970 N/mm2 (160 KSI) which also is the #1 body structure crossmember. Ultra high strength roll formed rear beam 1150 N/mm2 (190 KSI). polypropylene foam isolators designed for controlled energy management Thermoplastic olefin (TPO), injection molded fascias Two component urethane paint for long term color, gloss and scratch resistance. This bumper system, installed on over 100,000 vehicles so far, meets both MPV and passenger car 8 kph standards. Consumer and insurance industry trends indicate increasing demand for Multi Purpose Vehicle (MPV) bumper systems which meet 8 kph criteria. The major competitors in the MPV market (Aerostar, Grand Caravan, Toyota Previa, GM APV's, and Mazda MPV) have either 0 kph or at best 4 kph systems.

An estimate of the rate of attrition of passenger cars, needed to establish the service life expectancy of passenger cars, is of major interest whenever long range production plans are made, marketing strategies are developed, the total needs of vehicles on the roads are estimated, etc. Estimation of vehicle attrition is very complex, however, due to the lack of accurate data and the interaction of the parameters affecting attrition. In 1980 and 1985, similar studies of attrition [1,2] utilized vehicle registration data available as of July, 1979 and as of July, 1984. The object of this paper is to update the results of these papers, using the 1991 July registration data, available in May 1992. Within the scope of this paper the attrition rates of various passenger cars are compared and the effect of geographical location on the attrition rates and the change in attrition rates during the past twenty years are discussed.

A new method to predict brake squeal occurrence was developed by MSC under contract to Ford Motor Company. The results indicate that the stability characteristics of this disc brake assembly are governed mainly by the frictional properties between the pads and rotor. The stability is achieved when the friction coefficient of the pads is decreasing as the contact force increases. Based on the results, a stable brake system can be obtained without changing the brake structure by incorporating the appropriate frictional coefficient in the brake system. The method developed here can be also used as a tool to test the quality of any brake design in the early design stage.

A new laboratory test for measuring catalyst oxygen storage capacity has been developed. The test accurately predicts catalyst performance on the vehicle during transient A/F excursions and correlates well with vehicle CO and Nox tailpipe emissions. The test was subsequently used to facilitate improved oxygen storage capacity for new Pd-only washcoat formulations.

Statistical Energy Analysis (SEA) is a tool for estimating the response of complex dynamic systems at high modal density. This tool is seeing ever wider application in a range of industries, including aerospace industry, marine industry, and building trades. The automotive industry is beginning to explore the application of SEA to high frequency vehicle acoustic design. The SEA model of vibrational power transmission has a direct analogy to thermal power transmission (diffusion). As thermal power flow is proportional to temperature difference, vibrational power flow is proportional to modal energy difference. In this paper the thermal analogy is exploited to visualize the SEA results. This is accomplished by color coding a finite element representation of the structure. In this paper, the thermal analogy is used to correlate test data with SEA model results. This is accomplished by constructing a test based modal power thermogram.

In this paper, we introduce a numerically stable 2D computer model for sheet metal forming analysis based on the membrane theory. It simulates both axisymmetrical and plane strain cases with various restraining and friction conditions. We implemented a more realistic material model that accounts for cyclic loading and unloading. Also, the difficult frictional force reversal problem has been overcome. A simulation package released within Ford Motor Company has proven robust and accurate for applications to industrial cases.

This paper provides an overview of the dual EGO sensor method for OBD-II catalyst efficiency monitoring. The processes governing the relationship between catalyst oxygen storage, HC conversion efficiency, and rear EGO sensor response are reviewed in detail. A simple physical model relating catalyst oxygen storage capacity and rear EGO sensor response is constructed and used in conjunction with experimental data to provide additional insight into the operation of the catalyst monitor. The effect that the catalyst washcoat formulation has in determining the relationship between catalyst oxygen storage capacity and HC conversion efficiency and its impact on the catalyst monitor is also investigated. Lastly, the effects of catalyst failure mode, fuel sulfur, and the fuel additive MMT on the catalyst monitor's ability to properly diagnose catalyst function are discussed.

This paper begins with a comparison of the automotive power supply and loads in the early 1950's (near the end of the six-volt era) to the modern counterpart in the early 1990's (possibly near the end of the 12-volt era). A typical power supply specification sheet is developed based on the in-vehicle performance characteristics. From this summary, two attributes are noted: first, the system voltage is not very stable and second, transient protection is limited. With this awareness and the knowledge that the power supply of the future will need architectural change, a review of the design assumptions using a total system view and a long term outlook is advanced. Using a rule based design process and employing available technology to enhance the power system architecture, a number of elements are proposed for consideration in new designs.

The present work discusses an objective test and analysis method developed to quickly quantify steering gear rattle noise heard in a vehicle. Utilizing envelope analysis on the time history data of the rattle signal, the resulting method is simple, fast, practical and yields a single-valued metric which correlates well to subjective measures of rattle noise. In contrast to many other rattle analysis methods, the approach discussed here is completed in the time domain. As applied to rattle noise produced by automotive electric steering systems, the metric produced with this analysis method correlates well with subjective appraisals of vehicle-level rattle noise performance. Lastly, this method can also be extended to rattle measurements at the component and subcomponent level.