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As part of a continuing Ford Motor Company program to improve the seating packages of production cars, a simplified in-plant method was developed to check seating variations in production vehicles. The method also provided information helpful in determining causal factors when any irregularities were found. Equipment necessary for checking was designed to be easily transported to any site.

Unweighted dB, dB(A), and Articulation Index do not always accurately identify the sound quality of vehicle interior noise. This paper attempts to determine the relevance of sound quality in interior automotive acoustics. Traditionally, overall dB(A) levels have been the driving factor, along with cost, in selecting an interior automotive acoustic package. In this paper, we make use of subjective jury evaluations to compare perceptions of various interior acoustic packages and compare these results to objective values. These values include, but are not restricted to, dB, dB(A), and Articulation Index. Considerations are made as to whether differences between packages can be perceived by customers. This paper also attempts to show that subjective evaluations can differ with the standard metrics used to select acoustic packages and describe why such evaluations might be important in acoustic package selection.

Wavelets are a powerful mathematical tool used to multi-resolution time-frequency decomposition of signals, in order to analyze them in different scales and obtain different aspects of the information. Despite being a relatively new tool, wavelets have being applied in several areas of human knowledge, especially in signal processing, with emphasis in encoding and compression of image, video and audio. Based on a previous successful applications (FRAZIER, 1999) together a commitment to quality results, this paper evaluates the use of the Discrete Wavelet Transform (DWT) as an compression algorithm to reduce the amount of data collected in road load signals (load history) which are used by the durability engineering teams in the automotive industry.

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.

Until recently, tool & die making was a very traditional industry, relying on extensive know-how accumulated over decades of practice. Essentially, it remained a two stage-process: engineering/manufacture, followed by tryout/productionization. Improvements focused on engineering and production methods, but tryout remained the exclusive domain of the die maker. At last, advances in computer modeling methods and the adoption of aggressive lean management principles have brought transformational changes to the tryout phase. At the same time, new safety and weight imperatives have increased the penetration of advanced materials, whose formability characteristics are quite different from mild steels. This paper will explore how these advanced materials affect this transformation.

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.

Physical tests and analysis of a typical automobile latch and outside handle release mechanism are performed to determine the effects of friction on the systems dynamic response. An automobile side door outside handle, outside handle rod linkage, and latch are mounted to a rigid fixture that is constrained by bearings to a “drop tower.” The fixture is released from controlled heights onto a compliant impact surface resulting in a constant duration acceleration transient of varying amplitude. An instrumented door latch striker is designed into the fixture to engage the latch. The pre-drop interface load between the latch and striker is adjusted allowing its effect on the dynamic behavior to be characterized. The latch position and the interface load between the latch and striker are monitored throughout the test. The results of the test show that friction forces internal to the latch significantly affect the quasistatic and dynamic behavior of the latching system.

While SAE double inverted flares have been in use for decades, leaking joints continue to be a problem for OEMs in production settings consuming time and energy to detect and correct them before releasing vehicles from the assembly plant. It should be noted that this issue is limited to first-time vehicle assembly; once a flared brake tube joint is sealed at the assembly plant it remains sealed during normal customer usage. From their inception through the late 1980s most brake tubes have been 3/16″ nominal diameter. With the advent of higher flow requirements of Traction Control and Yaw/Stability control systems, larger tubes of 1/4″ and 5/16″ size have also been introduced. While it was known that the first-time sealing capability of the 3/16″ joint was not 100%, leakers were generally containable in the production environment and the joint was regarded as robust.

This paper deals with the dynamic characterization of an automotive shock absorber, a continuation of an earlier work [1]. The objective of this on-going research is to develop a testing and analysis methodology for obtaining dynamic properties of automotive shock absorbers for use in CAE-NVH low-to-mid frequency chassis models. First, the effects of temperature and nominal length on the stiffness and damping of the shock absorber are studied and their importance in the development of a standard test method discussed. The effects of different types of input excitation on the dynamic properties of the shock absorber are then examined. Stepped sine sweep excitation is currently used in industry to obtain shock absorber parameters along with their frequency and amplitude dependence. Sine-on-sine testing, which involves excitation using two different sine waves has been done in this study to understand the effects of the presence of multiple sine waves on the estimated dynamic properties.

Model low temperature NOx adsorbers (LTNA) consisting of Pd on a ceria/zirconia washcoat on monoliths were evaluated for low temperature NOx storage under lean conditions to assess their potential for adsorbing the cold-start NOx emissions on a diesel engine during the period before the urea/SCR system becomes operational. A reactor-based transient test was performed with and without C2H4, CO/H2, and H2O to assess the effects of these species on the NOx storage performance. In the absence of C2H4 or CO/H2, H2O severely suppressed the NOx storage of these model LTNAs at temperatures below 100°C, presumably by blocking the storage sites. When C2H4 was included in the feedgas, H2O still suppressed the NOx storage below 100°C. However, the C2H4 significantly increased the NOx storage efficiency above 100°C, attributable to the formation of alkyl nitrites or alkyl nitrates on the catalyst.

The process parameters to manufacture structural aluminum alloys are critical to their ductility. In particular, quench rate after solution heat treatment impacts the extent of grain boundary precipitation and the formation of precipitate free zone (PFZ) during later artificial aging. Cu-containing 6XXX alloys used for high strength automotive applications are quench sensitive as the Cu addition leads to Q-phase precipitation at grain boundaries, resulting in loss of ductility, which can negatively affect downstream manufacturing steps such as automotive joining and forming processes. Self-piercing rivet (SPR) joining, is a single step, spot joining process used to mechanically connect sheet materials together in automotive body structures. Ductility has been identified as an important metric of material rivet-ability or the ability to make a successful, crack-free SPR joint.

Joint stiffness is a major contributor to the vehicle body overall bending and torsional stiffness which in turn affects the vehicle NVH performance. Each joint consists of spot welds which function as load paths between adjacent sheet metal. Spot welds tend to lose structural integrity as a result of fatigue, loosening, aging, wear and corrosion of parts as a vehicle accumulates mileage. Experimental methods are used to identify potential degradation mechanisms associated with a spot weld. A CAE model which simulates a vehicle body joint generically is used to determine the effects of each individual degradation mode of a spot weld on joint stiffness. A real life B-pillar to roof joint CAE model of a production vehicle is then employed to examine the significance of weld distribution on joint stiffness degradation. The knowledge derived from this study can be used as a guidance in designing vehicle body structures with respect to spot weld distribution.

A study was performed on a lean NOx trap in which the loading of a ceria-containing mixed oxide in the washcoat was varied. After a mild stabilization of the traps, the time required to purge the NOx trap generally increased with increasing amount of mixed oxide. The purge NOx release also increased with increasing mixed oxide level but was greatly diminished after thermal aging. The sulfur tolerance of the NOx trap improved as the mixed oxide content was increased from 0% to 37%. The sample with 0% mixed oxide was more difficult to desulfate than the other samples due to poor water-gas-shift capability. After thermal aging, the NOx reduction efficiency on a 60 second lean/5 second rich cycle was highest for the samples with 0% to 37% mixed oxide at evaluation temperatures of 400°C to 500°C.

Technical Standards are essential for the expanded use of any engineering material. The Society of Automotive Engineers (SAE) Iron and Steel Castings Committee has been reworking existing, (and issuing new), standards for automotive iron and steel castings. This paper will review the status of the SAE standards for Ductile Iron, Austempered Ductile Iron (ADI), Compacted Graphite Iron (CGI) and high Silicon-Molybdenum (Si-Mo) Ductile Iron, Gray Iron and Steel Castings. The SAE Standards, (and draft standards), will be critically compared to those for ASTM and ISO. Salient differences in the standards will be discussed and implications to design engineers will be addressed. Comparisons to other, competitive materials (and their standards) will be made.

Industry trends towards lighter, more aerodynamically efficient road vehicles have the potential to degrade a vehicle’s response to crosswinds. In this paper, a methodology is outlined that indirectly couples a computational fluid dynamics (CFD) simulation of the vehicle’s aerodynamic characteristics with a multi-body dynamics simulation (MBD) to determine yaw, roll and pitch response characteristics during a severe crosswind event. This one-way coupling approach mimics physical test conditions outlined in open loop test procedure ISO 12021:2010 that forms part of the vehicle sign-off criterion at Ford Motor Company. The methodology uses an overset mesh CFD method to drive the vehicle through a prescribed crosswind event, providing unfiltered predictions of vehicle force and moment responses that are used as applied forces in the MBD model. The method does not account for changes in vehicle attitude due to applied aerodynamic forces and moments.

During the last decade, advances in magnesium die casting technology have enabled the production of large lightweight thin walled die castings that offer new approaches for low investment body construction techniques. As a result, many OEMs have expressed an interest in magnesium door closure systems due to investment reduction opportunities, coupled with potential weight savings of up to 50%. However, for such applications, product engineers are faced with the challenge of designing for stiffness and strength in crash critical applications with a material of lower modulus and ductility compared to wrought sheet product. Concept designs for side door systems have been presented in the literature, and indicate that structural performance targets can be achieved. However, to date, series production designs feature a multitude of supplementary sheet metal reinforcements, attached to die castings, to handle structural loads.

The Aluminum Beaker Oxidation Test is one of the tests specified for MERCONtm service ATF. The test is now being run at independent laboratories. Passing this and other specified tests is part of the process required to obtain a licence to describe an ATF as MERCONtm. The performance of test facilities at independent laboratories has been monitored by evaluating test data obtained with reference ATFs provided by Ford. The data so obtained, together with data obtained at Ford and other laboratories, have been used to generate a statistically significant data base. This data base has been used to better define test repeatability and reproducibility and thus provide an improved basis for monitoring the performance of test facilities. This paper provides a summary of the test procedure, reviews the data supporting the validity of the test, and presents information on the repeatability and reproducibility of the test method.

The aerodynamic development and characteristics of a four-passenger advanced concept automobile are described. An overview of the areas of the vehicle design which were dealt with to obtain a drag coefficient value of 0.153 is provided. The interior packaging philosophy is outlined which led to the potential for packaging four to six passengers within an extremely low drag automobile. Parametric shape studies of the major surface design elements are documented from the contributing development testing. The particular design treatments adopted and the rationale behind the choice of design are examined for each of the aerodynamically-sensitive areas of the vehicle. Examinations of the unique solutions to vehicle cooling, ramp and curb clearance, front wheel skirting and vehicle attitude are presented. Full scale wind tunnel data is shown for the configurations examined and vehicle stability parameters compared with conventional vehicles.

Globalization in the automotive industry has resulted in a tremendous competitive advantage to those companies who can internally communicate ideas and information effectively and in a timely manner. This paper discusses one such effort related to objectively testing vehicles for steering and handling characteristics by implementing standard test procedures, data acquisition hardware and analysis methods. Ford Motor Company's Vehicle Dynamics Test Section has refined a number of test procedures to the point that, with proper training, all design and development engineers can quickly acquire, analyze and share test results. Four of these procedures and output are discussed in detail.