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An L18 Taguchi-style Design of Experiments (DOE) with eight factors was used to optimize exterior mirrors for wind noise and drag. Eighteen mirror properties were constructed and tested on a full size greenhouse buck at the Lockheed low-speed wind tunnel in Marietta, GA. Buck interior sound data and drag measurements were taken at 80 MPH wind speed (0° yaw angle). Key wind noise parameters were the fore/aft length of mirror housing and the plan view angle of the mirror housing's inboard surface. Key drag parameters were the fore/aft length of the mirror housing, the cross-section shape of the mirror pedestal, and the angle of the pedestal (relative to the wind).

North American drivers particularly dislike wheel dust (brake dust on their wheels). For some vehicle lines, customer surveys indicate that wheel dust is a significant concern. For this reason, Ford and its suppliers are investigating the root causes of brake dust and developing test procedures to detect wheel dust issues up-front. Intuitively, it would appear that more brake wear would lead to more wheel dust. To test this hypothesis, a gage was needed to quantitatively measure the wheel dust. Gages such as colorimeters were evaluated to measure the brightness (L*) of the wheel, which ranged from roughly 70-80% (clean) to 10-20% (very dirty). Gage R&R's and subjective ratings by a panel of 30 people were used to validate the wheel dust gages. A city traffic vehicle test and an urban dynamometer procedure were run to compare the level of wheel dust for 10 different lining types on the same vehicle.

Recent applied mathematics research on the properties of the invertible shift-invariant discrete wavelet transform has produced new ways to visualize, separate, and synthesize impulsive sounds, such as thuds, slaps, taps, knocks, and rattles. These new methods can be used to examine the joint time-frequency characteristics of a sound, to select individual components based on their time-frequency localization, to quantify the components, and to synthesize new sounds from the selected components. The new tools will be presented in a non-mathematical way illustrated by two real-life sound quality problems, extracting the impulsive components of a windshield wiper sound, and analyzing a door closing-induced rattle.

Almost all published results of wake measurements for ground vehicles or similar shapes have included very limited information on streamwise development of wake structures. This is typically a result of the fact that the wake measurements have been conducted as parts of particular vehicle development efforts. So the focus has been on the incremental changes in the wakes associated with alternative geometries or buildup of various parts. The objectives are typically reached by limiting the surveys to a single streamwise plane. The present study, by contrast, is a study of wake development for a series of relatively simple rectangular shapes with radiused edges with a systematic variation in the ratio of height to width or “Aspect Ratio”.

High gas prices combined with demand for improved fuel economy have prompted increased interest in diesel engine applications for both light-duty and heavy-duty vehicles. The development of aftertreatment systems for these vehicles requires significant investments of capital and time. A reliable and robust qualification testing procedure will allow for more rapid development with lower associated costs. Qualification testing for DPFs has its basis in methods similar to DOCs but also incorporates a PM loading method and regeneration testing of loaded samples. This paper examines the effects of accelerated loading using a PM generator and compares PM generator loaded DPFs to engine dynamometer loaded samples. DPFs were evaluated based on pressure drop and regeneration performance for samples loaded slowly and for samples loaded under accelerated conditions. A regeneration reactor was designed and built to help evaluate the DPFs loaded using the PM generator and an engine dynamometer.

Through the use of hybrid technology, Ford Motor Company continues to realize enhanced vehicle fuel economy while meeting customer performance and drivability targets. As is characteristic of all Ford Hybrid Electric Vehicles (HEVs), the basis for resolving these competing requirements resides with its Vehicle System Control (VSC) strategy. This strategy implements complex high-level executive controls to coordinate and optimize the desired operational state of the major HEV powertrain subsystems. To ensure that the VSC software meets its intended functionality, a software validation process developed at Research and Advanced Engineering has been integrated as part of the vehicle controls development process. In this paper, this VSC software validation process implemented for a next generation hybrid powertrain is presented. First, an overview of the hybrid powertrain application and the VSC software architecture is introduced.

The USDOT and the Crash Avoidance Metrics Partnership-Vehicle Safety Communications 2 (CAMP-VSC2) Consortium (Ford, GM, Honda, Mercedes, and Toyota) initiated, in December 2006, a three-year collaborative effort in the area of wireless-based safety applications under the Vehicle Safety Communications-Applications (VSC-A) Project. The VSC-A Project developed and tested communications-based vehicle safety systems to determine if Dedicated Short Range Communications (DSRC) at 5.9 GHz, in combination with vehicle positioning, would improve upon autonomous vehicle-based safety systems and/or enable new communications-based safety applications.

The United States Department of Transportation (USDOT) and the Crash Avoidance Metrics Partnership-Vehicle Safety Communications 2 (CAMP-VSC2) Consortium (Ford, General Motors, Honda, Mercedes-Benz, and Toyota) initiated, in December 2006, a three-year collaborative effort in the area of wireless-based safety applications under the Vehicle Safety Communications-Applications (VSC-A) Project. The VSC-A Project developed and tested Vehicle-to-Vehicle (V2V) communications-based safety systems to determine if Dedicated Short Range Communications (DSRC) at 5.9 GHz, in combination with vehicle positioning, would improve upon autonomous vehicle-based safety systems and/or enable new communications-based safety applications.

In this study, tests were performed with modified tires at the right rear location on a solid rear axle sport utility vehicle to compare the vehicle inputs from both: (1) tire tread belt detachments staged by circumferentially cut tires, and (2) a tire tread detachment staged by distressing a tire in a laboratory environment. The forces and moments that transfer through the road wheel were measured at the right and left rear wheel locations using wheel force transducers; displacements were measured between the rear axle and the frame at the shock absorber mounting locations, ride height displacements were measured at the four corners of the vehicle, and accelerations were measured on the rear axle. Onboard vehicle accelerations and velocities were measured as well. The data shows that the tire tread belt detachments prepared by circumferentially cut tires and distressed tires have similar inputs to the vehicle.

The increasing trend toward electric and hybrid-electric vehicles (HEVs) has created unique challenges for NVH development and refinement. Traditionally, characterization of in-vehicle powertrain noise and vibration has been assessed through standard operating conditions such as fixed gear engine speed sweeps at varied loads. Given the multiple modes of operation which typically exist for HEVs, characterization and source-path analysis of these vehicles can be more complicated than conventional vehicles. In-vehicle NVH assessment of an HEV powertrain requires testing under multiple operating conditions for identification and characterization of the various issues which may be experienced by the driver. Generally, it is necessary to assess issues related to IC engine operation and electric motor operation (running simultaneously with and independent of the IC engine), under both motoring and regeneration conditions.

Two finite element methodologies for simulating oil-canning tests on closure assemblies are presented. Reflecting the experimental conditions, the simulation methodologies assume load-controlled situations. One methodology uses an implicit finite-element code, namely ABAQUS®, and the other uses an explicit code, LS-DYNA®. It is shown that load-displacement behavior predicted by both the implicit and explicit codes agree well with experimental observations of oil-canning in a hood assembly. The small residual dent depth predictions are in line with experimental observations. The method using the implicit code, however, yields lower residual dent depth than that using the explicit code. Because the absolute values of the residual dent depths are small in the cases examined, more work is needed, using examples involving larger residual dent depth, to clearly distinguish between the two procedures.

To manage the function of a vehicle's engine, transmission, and related subsystems, almost all modern vehicles make use of one or more electronic controllers running embedded software, henceforth referred to as a Powertrain Controller System or PCS. Fully validating this PCS is a necessary step of vehicle development, and the validation process requires extensive amounts of testing. Traditionally, this validation testing is done with open-loop signal generators, powertrain dynamometers, and real vehicles. Such testing methods either cannot simulate complex control system interactions, or are expensive and subject to variability. To address these concerns while decreasing development time and improving vehicle quality, Ford Motor Company is placing increasing focus on validating a PCS through simulation. One such testing method is a Hardware-in-the-Loop (HIL) simulation, which mates the physical elements of a PCS to a real-time computer simulation of a powertrain.

This paper reports a study of the dynamic characteristics of body mounts in body on frame vehicles and their effects on structural and occupant CAE results. The body mount stiffness and damping are computed from spring-damper models and component test results. The model parameters are converted to those used in the full vehicle structural model to simulate the vehicle crash performance. An effective body mount in a CAE crash model requires a set of coordinated damping and stiffness to transfer the frame pulse to the body. The ability of the pulse transfer, defined as transient transmissibility[1]1, is crucial in the early part of the crash pulse prediction using a structural model such as Radioss[2]. Traditionally, CAE users input into the model the force-deflection data of the body mount obtained from the component and/or full vehicle tests. In this practice, the body mount in the CAE model is essentially represented by a spring with the prescribed force-deflection data.

For suspension systems, fatigue and strength simulations are accomplished mostly at the component level. However, the selection of loading conditions and replication of boundary conditions at the component level may be difficult. A system level simulation eliminates most of the discrepancy between component level and vehicle level environment yielding realistic results. Further advantage of system level simulation is that the boundary conditions are limited to suspension mounting points at body or frame and the loading is limited to wheel-end or tire patch loading. This provides for a robust set of boundary constraints that are known and repeatable, and loads that are simpler and of relatively higher accuracy. Here, the nonlinear transient dynamic behavior of a suspension system along with its frame and mounting was simulated using a multibody finite element analysis (FEA).

The paper describes a new tire cornering/traction trailer designed to measure the traction and steering performance of passenger car tires, outlines related test methods, and provides supporting test data. A general set of specifications is given for the entire test system. The major subsystems described are the trailer with its versatile suspension; the tow vehicle and its performance capabilities; the transducer system which measures the normal load, lateral force, fore-and-aft force, aligning torque, steer angle and speed; and the instrumentation. The calibration method is described. The test methods described include those for straight-line braking, maximum lateral traction, steady state and transient steering response, and combined braking and cornering traction. Supporting data and discussion are presented for each test method.

Thermally sprayed coatings have used in place of iron bore liners in recent aluminum engine blocks. The coatings are steel-based, and are sprayed on the bore wall in the liquid phase. The thermal response of the block structure determines how rapidly coatings can be applied and thus the investment and floor space required for the operation. It is critical not to overheat the block to prevent dimensional errors, metallurgical damage, and thermal stress cracks. This paper describes an innovative finite element procedure for estimating both the substrate temperature and residual stresses in the coating for the thermal spray process. Thin layers of metal at a specified temperature, corresponding to the layers deposited in successive thermal spray torch passes, are applied to the substrate model, generating a heat flux into the block. The thickness, temperature, and application speed of the layers can be varied to simulate different coating cycles.

Over the past five years, the US Automotive Materials Partnership (USAMP) has brought together representatives from DaimlerChrysler, General Motors, Ford Motor Company and over 40 other participant companies from the Mg casting industry to create and test a low-cost, Mg-alloy engine that would achieve a 15 - 20 % Mg component weight savings with no compromise in performance or durability. The block, oil pan, and front cover were redesigned to take advantage of the properties of both high-pressure die cast (HPDC) and sand cast Mg creep- resistant alloys. This paper describes the alloy selection process and the casting and testing of these new Mg-variant components. This paper will also examine the lessons learned and implications of this pre-competitive technology for future applications.

The concept of vehicle understeer and oversteer has been well studied and equations, test methods, and test results have been published for many decades. This concept has a specific definition in the steady-state driving range as opposed to quantification in highly transient limit handling events. There have been specific test procedures developed and employed by automotive engineers for decades on how to quantify understeer. These include the constant radius method, the constant steering wheel angle/variable speed method, the constant speed/ variable radius method, and the constant speed/variable steer method. These methods are very good for calculating the understeer gradient but care must be taken in interpreting the result at the limits of tire traction since lateral tire forces can be reduced on a drive axle when significant throttle is applied.

The objective of the P2000 body structure design was to provide a body structure with 50% of the mass of current mid-size production vehicles while maintaining all the safety, durability, NVH and other functional attributes. In addition, the design was to be consistent with the PNGV affordability objectives and high volume production by 2005. This paper describes the P2000 body structure including the structural philosophy, project constraints on the design, manufacturing processes, supporting analyses, assembly processes and unique material and design concepts which resulted in the 50% weight reduction from comparable production vehicles.

The Ford Spin Torsional NVH TEST Facility developed and completed in 1999 as a state-of-the-art powertrain NVH development facility(1). Since then, various designed capabilities have been verified with test vehicles for multiple applications to facilitate powertrain NVH development. This paper describes fundamental capabilities of the test facility, including input module to simulate engine torque signatures of arbitrary engines (“virtual engine” capability) and absorbing dynamometer systems, functioning as a precision 4WD/AWD chassis dynamometer. The correlation between road test/chassis dynamometer test and Spin-Torsional test is then illustrated, verifying high correlation of vehicle/sub-system responses between conventional vehicle testing and Spin-Torsional test results.