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Four multigrade engine oils, containing the same base oil plus SE additive package but VI improvers of differing shear stability, were evaluated in 80 000 km of high-speed, high-temperature vehicle service. Bearing, piston ring and valve guide wear, as well as oil consumption, oil filter plugging and engine cleanliness were all worse for the engines operated on the low-shear stability oils. The wear differences were traced to differences in high-shear-rate viscosity, while the cleanliness, filter plugging and oil consumption differences occurred because of excessive wear or polymer shear degradation. These results suggest that engine oil viscosity should be specified under high-shear-rate conditions.

Since their introduction in automobiles, polymeric materials have enabled designers and engineers to differentiate products based on performance attributes, mechanical response, aesthetics, and manufacturing techniques. A large segment of these applications utilizes polypropylene (PP) resins. One of the attractive features of PP polymers is the ability to tailor their mechanical, thermal and processing performance envelope via modification of their composition and the addition of fillers. Key to the successful application of PP resins in structural systems is the ability of designers and engineers to understand the material response and to properly model the behavior of PP structures upon different mechanical and thermal loading conditions.

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.

Since 1985, the Body Division of the Automotive Corrosion and Prevention Committee of SAE (ACAP) has conducted biannual surveys of automotive body corrosion in the Detroit area. The purpose of these surveys is to track industry wide corrosion protection improvements and to make this information available for public consumption. The survey consists of a closed car parking lot survey checking for perforations, blisters, and surface rust. This paper reports the results of the five surveys conducted to date.

The Body Division of the Automotive Corrosion and Prevention Committee of SAE (ACAP) has conducted biannual surveys of automotive body corrosion in the Detroit area since 1985. The purpose of these surveys is to track industry-wide corrosion protection improvements and to make this information available for public consumption. The survey consists of a closed car parking lot survey checking for perforations, blisters, and surface rust. This paper reports the results of the seven surveys conducted since 1985.

A detailed description of the oxidative stability of GM's DEXRON®-VI Factory Fill Automatic Transmission Fluid (ATF) is provided, which can be integrated into a working algorithm to estimate the end of useful oxidative life of the fluid. As described previously, an algorithm to determine the end of useful life of an automatic transmission fluid exists and is composed of two simultaneous counters, one monitoring bulk oxidation and the other monitoring friction degradation [1]. When either the bulk oxidation model or the friction model reach the specified limit, a signal can be triggered to alert the driver that an ATF change is required. The data presented in this report can be used to develop the bulk oxidation model. The bulk oxidation model is built from a large series of bench oxidation tests. These data can also be used independent of a vehicle to show the relative oxidation resistance of this fluid, at various temperatures, compared to other common lubricants.

Modular front-end carriers to pre-assemble front-end components such as cooling systems, lights, and bumper beam have been in production in different vehicles for several years. Compression molded or overmolded steel/plastic carriers have traditionally been used. The present paper explains the design, material options, and engineering optimization of a composite front-end carrier, which utilizes long glass fiber injection moldable resins and adhesively bonded steel reinforcements. Experimental evaluation of prototypes shows the system met the functional performance requirements at minimum weight.

A study was conducted by General Motors at its crash test facility located at the Milford Proving Ground. The intent of this study was to expand upon the currently available research regarding the safety belt buckle environment during full scale planar crash tests. Buckle accelerations and webbing tensions were measured and recorded to characterize, in part, buckle responses in a crash environment. Previous studies have focused primarily on the component level testing of safety belt buckles. The crash tests included a variety of vehicles, impact types, seating positions, Anthropomorphic Test Devices (ATDs), impact speeds, and impact angles. Also included were various safety belt restraint systems and pretensioner designs. This study reports on data recorded from 100 full scale crash tests with 180 instrumented end release safety belt buckles. Acceleration measurements were obtained with tri-axial accelerometers mounted onto the buckles.

This paper presents an extensive research program undertaken to develop improved side impact test methods. The development of a component side impact test device along with an associated test procedure are reviewed. The results of accident data analysis techniques to define anatomical areas most likely to be injured during side impact and definition of test device response corridors based on human surrogate testing conducted by the Association Peugeot/Renault and the University of Heidelberg are discussed. The relationship of response corridors and accident data analysis in earlier phases of the project resulted in definition and development of a component side impact test device to represent the human thorax. A test program to evaluate and compare component and full-vehicle test results is presented.

This paper presents the results of a series of over 30 impact sled simulations of racing car frontal crashes conducted as part of the GM Motorsports Safety Technology Research Program. A Hyge™ impact sled fitted with a simulated racing car seat and restraint system was used to simulate realistic crash loading with a mid-size male Hybrid III dummy. The results of tests, in the form of measured loads, displacements, and accelerations, are presented and comparisons made with respect to the levels of these parameters seen in typical passenger car crash testing and to current injury threshold values.

The Auto/Steel Partnership established the Light Truck Frame Project Group in 1996 with two objectives: (a) to develop materials, design and fabrication knowledge that would enable the frames on North American OEM (original equipment manufacturer) light trucks to be reduced in weight, and (b) to improve corrosion resistance of frames on these vehicles, thereby allowing a reduction in the thickness of the components and a reduction in frame weight. To address the issues relating to corrosion, a subgroup of the Light Truck Frame Project Group was formed. The group comprised representatives from the North American automotive companies, test laboratories, frame manufacturers, and steel producers. As part of a comprehensive test program, the Corrosion Subgroup has completed tests on frame coatings. Using coated panels of a low carbon hot rolled and pickled steel sheet and two types of accelerated cyclic corrosion tests, seven frame coatings were tested for corrosion performance.

The performance and production requirements for future passenger vehicles has increased the efforts to replace metal body panels with plastic materials. This has been accomplished, to a large extent on some production vehicles that have been introduced recently. Unfortunately, these plastic body applications have necessitated special off-line handling or low temperature paint processing. However, the advantages of RIM nylon, offer the potential for uniquely new plastic body designs, that can be processed through existing assembly plants, much like the steel panels they are intended to replace. The intent of this paper is to discuss the rationale for future plastic body panel material selection and related nylon RIM development efforts.

This paper describes a numerical simulation technique applicable to the FMVSS 214 side impact test through the use of the finite element method (FEM) technology. The paper outlines the development of the side impact dummy (SID), moving deformable barrier (MDB) and the test vehicle FEM models, as well as the development of new advanced constitutive models of materials and algorithms in LS-DYNA3D which are related to the topic. Presented in the paper are some initial simulation problems which were encountered and solved, as well as the correlation of the simulation data to the physical test.

Polyamide resins are well established within the automotive industry and are widely used in a range of demanding under-the-hood applications such as valve covers and air intake manifolds. In reality however, the disadvantages of conventional nylon products, such as excessive warpage and poor dimensional stability to name but two, make it increasingly difficult for engineers to produce the ever more complex parts demanded by new engine developments. In this paper we shall introduce a new range of modified Dow Polyamide resins that greatly reduce the above mentioned disadvantages. In comparisons with commercially available nylon 6 and 66 materials we shall illustrate improved warpage behaviour and lower moisture pick-up in combination with excellent chemical resistance to, for example, hot motor oil and ethylene glycol. In summation, examples will be provided to illustrate the improved utility of these new, modified Dow Polyamide resins.

Side impact dummy (SID) is a human-like test device used in the National Highway Transportation Safety Administration (NHTSA) mandated side impact test of vehicles sold in the USA. A finite element model of SID has been developed at GM as a part of a project to simulate the side impact test. The objective is to better predict physical test results by replacing traditional rigid-body lumped parameter models with a finite element model. The project included, besides mesh generation, the development of new LS-DYNA3D constitutive models for rubber and foam-like materials, and enhancements of contact interface and other algorithms. This paper describes the GM SID finite element model and its performance in side impact test simulations.

Automotive manufacturers are driving for improvement, creativity and innovation in vehicle systems in order to differentiate products in the global market. Progress in fuel efficiency, occupant safety, comfort, recyclable friendly pre-assembled modular systems, and novel manufacturing methods is difficult to achieve if no major departure from the traditional design, engineering, material mix, and assembly approaches is considered. More importantly, these benefits will not materialize unless the relationship between automotive manufacturers and suppliers changes, allowing suppliers to take a more active role in the vehicle development process. The present paper explores achievements made towards the development of new, innovative technologies to address simplification and overall performance improvements using non-traditional materials.

A relationship between the risk of significant thoracic injury (AIS ≥ 3) and Hybrid III dummy sternal deflection for shoulder belt loading is developed. This relationship is based on an analysis of the Association Peugeot-Renault accident data of 386 occupants who were restrained by three-point belt systems that used a shoulder belt with a force-limiting element. For 342 of these occupants, the magnitude of the shoulder belt force could be estimated with various degrees of certainty from the amount of force-limiting band ripping. Hyge sled tests were conducted with a Hybrid III dummy to reproduce the various degrees of band tearing. The resulting Hybrid III sternal deflections were correlated to the frequencies of AIS ≥ 3 thoracic injury observed for similar band tearing in the field accident data. This analysis indicates that for shoulder belt loading a Hybrid III sternal deflection of 50 mm corresponds to a 40 to 50% risk of an AIS ≥ 3 thoracic injury.

Car manufacturers continue to strive to find creative routes to differentiate their vehicles while continuing to reduce cost. Acoustic comfort derived from high performance sprayable dampener systems is one important option for OEM's to differentiate their models. But there is a significant conflict between high performance, low cost and vehicle weight reduction. This paper describes an innovative vibration dampening material resin. It is a one part, reactive, solvent free, sprayable, epoxy based technology using a unique polymer resin with reduced safety labeling requirements. Good corrosion protection and oil absorption characteristics allow this resin to be applied in either the body or paint shop facilities. Benchmarking against the existing dampener type in the areas of damping performance, process costs, ease of application and environment/health aspects shows that this new generation of epoxy damper is superior to other current damper coatings.

During early 2005 General Motors released a newly developed ATF for the factory fill of all GM Powertrain stepped gear automatic transmissions. The new fluid provided significantly improved performance in terms of friction durability, viscosity stability, aeration and foam control and oxidation resistance. In addition, the fluid has the potential to enable improved fuel economy and extended drain intervals. Since the performance of the new fluid far exceeded that of the DEXRON®-III service fill fluids available at the time it became necessary to upgrade the DEXRON® service fill specification in order to ensure that similar fluids were available in the market for service and repair situations. This latest upgrade to the service fill specification is designated DEXRON®-VI [1].

Reducing the wall thickness of automotive fascia offers cost and weight savings over those manufactured today. New high performance RIM polyurethane/urea and polyurea polymers with improved mechanical properties over conventional systems make down-gauging possible while maintaining specified performance.1 Adding low cost, high surface quality fillers to these polymers provides enhanced dimensional stability in fascia at reduced wall thickness, thus meeting ever increasing demands for lower cost and high quality. This paper describes validation studies of filled RIM fascia down-gauged 22% to 3.0 mm wall thickness and compares them to conventional fascia moulded at nominal 3.9 mm wall thickness. High performance polyurethane/urea, polyurea, and conventional polyurethane/urea each incorporating wollastonite, mica, or milled glass were tested. The data include “on-car position” moisture stability, painted impact at low temperature, and material processing.