Search Results

Engineers doing squeak and rattle testing of instrument panels (IP's) have successfully used large electrodynamic vibration systems to identify sources of squeaks and rattles (S&R's). Their successes led to demands to test more IP's, i.e., to increase throughput of IP's to reflect the many design, material, and/or manufacturing process changes that occur, and to do so at any stage of the development, production, or QA process. What is needed is a radically different and portable way to find S&R's in a fraction of the time and at lower capital cost without compromising S&R detection results.

The Kinematic Analysis Methods Computer Program that has been used by Ford Motor Co. to evaluate mechanisms for the past four years has been modified to generate performance curves for windshield wiper linkages directly using a Calcomp Plotter. Problems such as stalling, “jerky” operation, and excessive phase lag between wipers can be detected early in the design stages by careful evaluation of the curves.

Automotive outside rear view mirror shape has become an important consideration in achieving wind noise and aerodynamic performance objectives. This paper describes a two step process used to develop a mirror shape which meets both wind noise and aerodynamic objectives. First, basic understanding of door mounted verses sail mounted mirrors and shape parameters was obtained by evaluating selected shapes and studying their physical measurements relative to their measured responses. Relationships between the wind noise and drag responses revealed performance range limitations for sail mounted mirrors. Second, a central composite experimental design was utilized to more closely investigate door mounted mirror shape parameters to determine optimal mirror performance potential. The resulting empirical models developed were used to determine the best overall solution.

Wind noise is the sound made as air rushes over a moving vehicle. As other vehicle sound sources are improved, the wind noise becomes the dominant source under certain conditions. The purpose of this paper is to examine the relationship between the properties of wind noise and the human perception of this sound.We find that a particular loudness measure (Zwicker loudness as defined in IS0532B) is the prime factor governing the customer perception of wind noise.

A series of tests have been performed on a production vehicle to determine the characteristics of the external turbulent flow field in wind tunnel and road conditions. Empirical formulas are developed to use the measured data as source levels for a Statistical Energy Analysis (SEA) model of the vehicle structural and acoustical responses. Exterior turbulent flow and acoustical subsystems are used to receive power from the source excitations. This allows for both the magnitudes and wavelengths of the exterior excitations to be taken into account - a necessary condition for consistently accurate results. Comparisons of measured and calculated interior sound levels show good correlation.

This paper presents the extended Kalman filter-based sideslip angle estimator design using a nonlinear 5DoF single-track vehicle dynamics model with stochastic modeling of tire forces. Lumped front and rear tire forces have been modeled as first-order random walk state variables. The proposed estimator is primarily designed for vehicle sideslip angle estimation; however it can also be used for estimation of tire forces and cornering stiffness. This estimator design does not rely on linearization of the tire force characteristics, it is robust against the variations of the tire parameters, and does not require the information on coefficient of friction. The estimator performance has been first analyzed by means of computer simulations using the 10DoF two-track vehicle dynamics model and underlying magic formula tire model, and then experimentally validated by using data sets recorded on a test vehicle.

Panel acoustic contribution analysis (PACA) is an advanced engineering tool to improve the NVH quality of vehicles. Using PACA areas of vehicle body panels are categorized according to their contribution to the total sound. Positive contribution areas increase the sound level as vibration amplitude increases, negative contribution areas decrease the sound level as vibration amplitude increases, and neutral areas have no significant effect on the sound level. This knowledge is important to guide vehicle NVH refinement. This paper presents the technical approach of PACA and the results of an experiment used to validate the PACA techniques. Vehicle application results to improve NVH quality and reduce weight are also included.

The Vehicle Electrical System Computer Aided Design (VESCAD) tool is a means by which the vehicle electrical system, including all wiring and the components attached to wiring can be laid out over an outline of the planform (looking down on the vehicle) view of the vehicle. This graphical representation of the vehicle electrical system is linked to a database that contains the definition of all the wiring of the vehicle plus electrical component attributes. The vehicle electrical system can be composed and completely manipulated graphically, using a mouse, and the database is dynamically changed, including automatic re-routing of the wiring in the wiring harnesses. A complete series of reports can be generated once a vehicle electrical system is configured using VESCAD. All of the reports can be keyed by component(s), harness(es), subsystem(s) or the entire vehicle.

The dynamic characteristics of a vehicle are an important part of the driver's experience. Ford Motor Company is actively pursuing a leadership role in this arena. To achieve this goal, all the necessary information to complete the vehicle dynamics picture of a vehicle must be gathered in an efficient and well-organized manner. A process was developed to fingerprint a vehicle so that this information could drive vehicle tuning, new Computer Aided Engineering (CAE) models, correlate existing CAE models, support problem resolution and conduct target setting. This paper will discuss a Vehicle Dynamics Fingerprint Process in detail and explain the steps involved.

Brake related warranty costs are a major concern to the automotive industry. Large part of these costs are due to noise, more particularly due to the brake squeal complaints. Computer-aided engineering solutions have attracted a lot of attention from the engineering and development community for more effective brake product development. Recently, three brake squeal analysis methods were implemented on disc type brakes in a vehicle program at Ford. This paper summarizes the results and documents the experience obtained during implementation in the vehicle CAE process.

Liquid fuels and the fuel vapors in equilibrium with them typically differ in composition. These differences impact automotive fuel systems in several ways. Large compositional differences between liquid and vapor phases affect the composition of species taken up within the evaporative emission control canister, since the canister typically operates far from saturation and doesn't reach equilibrium with the fuel tank. Here we discuss how these differences may be used to diagnose the mode of emission from a sealed container, e.g., a fuel tank. Liquid or vapor leaks lead to particular compositions (reported here) that depend on the fuel components but are independent of the container material. Permeation leads to emissions whose composition depends on the container material. If information on the relative permeation rates of the different fuel components is available, the results given here provide a tool to decide whether leakage or permeation is the dominant mode of emission.

The worldwide automotive industry is currently preparing for a market introduction of hydrogen-fueled powertrains. These powertrains in fuel cell electric vehicles (FCEVs) offer many advantages: high efficiency, zero tailpipe emissions, reduced greenhouse gas footprint, and use of domestic and renewable energy sources. To realize these benefits, hydrogen vehicles must be competitive with conventional vehicles with regards to fueling time and vehicle range. A key to maximizing the vehicle's driving range is to ensure that the fueling process achieves a complete fill to the rated Compressed Hydrogen Storage System (CHSS) capacity. An optimal process will safely transfer the maximum amount of hydrogen to the vehicle in the shortest amount of time, while staying within the prescribed pressure, temperature, and density limits. The SAE J2601 light duty vehicle fueling standard has been developed to meet these performance objectives under all practical conditions.

A survey of industrial control computer applications presently operational in this user's facilities revealed an approximate 50/50 division between those that were internally and externally implemented. Problems encountered in the planning, launching, and follow-up phase of system installation were found to be common to both internal and external system implementations and are categorized and evaluated as being inherent and environmental in nature. In an effort to avoid anticipated problems characteristic of a computerized installation, proper staffing as an inhouse project team is essential. During the process of developing inhouse talent, three plateaus of system implementation maturity are attained. These plateaus range from complete dependency upon outside assistance to “do it yourself” inhouse implementation. Flow charts are developed to depict typical decision paths leading to a plateau of system implementation most appropriate for the particular user “turnkey dilemma.”

During frontal and rear end type collisions, very large forces will be imparted to the passenger compartment by the collapse of either front or rear structures. NCAP tests conducted by NHTSA involve, among other things, a door openability test after barrier impact. This means that the plastic/irreversible deformations of door openings should be kept to a minimum. Thus, the structural members constituting the door opening must operate during frontal and rear impact near the elastic limit of the material. Increasing the size of a structural member, provided the packaging considerations permit it, may prove to be counter productive, since it may lead to premature local buckling and possible collapse of the member. With the current trend towards lighter vehicles, recourse to heavier gages is also counterproductive and therefore a determination of an optimum compartment structure may require a number of design iterations. In this article, FEA is used to simulate front side door behavior.

In nowadays market, highlighted by global products, companies are pushed to sell products that comply with legal and customer requirements in different countries and, not unusually, different continents. In order to achieve such challenge, and pressed to reduce project and production costs, companies are spreading design centers around the world, based on regional expertise. These excellence centers must work together to benefit from synergies and local skills from different regions. Such projects are staffed by Virtual Team (BINDER, 2007), whose members barely face each other. This means teams will work frequently with people they have never met, who live on different time zones and have different cultures. As a consequence, communication is done basically through computer-based media, mainly based on emailing, and must be even clearer and more direct than with the people who work on the next desk.

Because it is common to attach plastic parts to other plastic, metal, or ceramic assemblies with mechanical fasteners that are often stronger and stiffer than the plastic with which they are mated, it is important to be able to predict the retention of the fastener in the polymeric component. The ability to predict this information allows engineers to more accurately estimate length of part service life. A study was initiated to understand the behavior of threaded fasteners in bosses molded from engineering thermoplastic resins. The study examined fastening dynamics during and after insertion of the fastener and the effects of friction on the subsequent performance of the resin. Tests were conducted at ambient temperatures over a range of torques and loads using several fixtures that were specially designed for the study. Materials evaluated include modified-polyphenylene ether (M-PPE), polyetherimide (PEI), polybutylene terephthalate (PBT), and polycarbonate (PC).

Suspension roll centers are currently used to establish vehicle handling characteristics such as under-steer and feel. Roll centers were developed to help understand vehicle designs on paper. Computers and mechanism simulation software allows vehicle models to be built and analyzed. Analyzing forces and moments may be a better technique as opposed to modeling suspension roll centers. A proposed method is to look directly at forces applied to the vehicle body and moments resulting from the applied forces. This force-moment method includes the effects of load transfer and tread change, which are not accounted for by geometric roll centers.

In 1998, the United States Field Trial was chartered by the United States Council for Automotive Research/Vehicle Recycling Partnership with the objective of evaluating the feasibility of collecting and recycling automotive polymers from domestic end-of-life Vehicles (ELVs). Although ELVs are among the most widely recycled consumer products, 15-25% of their total mass must nevertheless be disposed of with no material recovery; the majority of this remainder is polymeric. Concerns regarding vehicle abandonment risks and disposal practices have resulted in the legislated treatment of ELVs in Western Europe, and in the emergence of attendant material recycling schemes. These schemes support quantitatively optimized material collection, but do not appear to be sustainable under the free-market economic conditions prevalent in North America.

In 1985, the Body Division of the Automotive Corrosion and Prevention Committee of SAE (ACAP) concluded that an automotive body corrosion survey for public consumption was needed. The committee proceeded to develop a survey methodology and conducted surveys in the Detroit area every second year starting in 1985. The survey is a closed car parking lot survey of nineteen panels or partial panels checking for perforations, blisters and surface rust. Similar surveys have and will continue to be conducted at biyearly intervals for comparison purposes to track the results of industry wide corrosion protection “improvements”. This is a report of the results of the first three surveys. THE ACAP COMMITTEE BODY DIVISION has now completed the third in its series of biyearly surveys. It is now possible to see some very clear results of industry actions and some indication of future performance.

This report is a comprehensive investigation into the use of resin transfer molded glass fiber reinforced plastics in a structural application. A pickup truck cab structure is an ideal application for plastic composites. The cab is designed to fit a production Ranger pickup truck and uses carryover frame and front end structure. The cab concept consists primarily of two molded pieces. This design demonstrates extensive parts integration and allows for low-cost tooling, along with automated assembly.