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The scope of this SAE Recommended Practice is to describe the maximum recommended voltage drop for starting motor circuits for 6 V through 32 V starters.

Over the past several years many differently sized dry-type air cleaner elements have been manufactured to service the numerous makes and models of United States domestic passenger cars and light trucks. This has led to inventory and stock control inefficiencies that affect the motoring public, the automobile manufacturers, and the air cleaner producers. Currently, there are hundreds of different air cleaner elements required to service these vehicles. The SAE Air Cleaner Test Code Subcommittee, recognizing the need for standardization of air cleaners has compiled a list of the 25 most used round type and the most used panel type elements. Automotive engineers responsible for the design of engine air induction systems on new applications are encouraged to select a dry-type air cleaner element from these lists. It is expected that by adhering to this recommendation that the currently most popular elements will be chosen for new applications to eliminate further proliferation.

The Token Slot Data Link is intended to provide periodic, broadcast communications (communication that must occur on a regular, predetermined basis) within a vehicle system. The Token Slot protocol achieves this by implementing a masterless, deterministic, non-contention Token Slot sequence which is designed to offer a transmit token to all devices (or nodes) without requiring that they respond. After acquiring the token, messages may be sent and verified using a variety of built-in techniques. The token passing slot sequence is then reinitiated by the current token holder.

This SAE Recommended Practice defines, for vehicle manufacturers and collision information and equipment providers, the types of vehicle dimensional data needed by the collision repair industry and aftermarket equipment modifiers to properly perform high-quality repairs to damaged vehicles. Both body-frame and unitized vehicles, including passenger cars and light trucks, are addressed.

The Society of Automotive Engineers task force on headlamp mounting height has considered the ramifications of reducing the maximum mounting height of headlamps on highway vehicles. The task force has concluded that it is in the best interest of the driving public to make a significant reduction in the recommended maximum height at which headlamps, particularly lower beam headlamps, may be mounted. Heights as low as 36 to 40 in (0.9 to 1.0 m) have been considered. New tractor vehicles are in fact being designed with headlamps mounted in this range. Further recommendations were withheld in anticipation of tests to demonstrate the effect of mounting height on the legibility of certain overhead signs.

This specification covers a corrosion and heat resistant nickel alloy in the form of wire.

Tolerance stackups rank among the more important tools available to a design team for gaining insight into a product design. Careful allocation of tolerances between the features in a product help balance the often conflicting requirements of design and manufacturing. Prototypes of new products are expected to assemble and function with little difficulty. When designing a new product that is part of a large product family, tolerance stackups are even more important. The sub-assemblies that make up a product family must be interchangeable and the interactions between sub-assemblies must be well understood. This paper will discuss various aspects of stackups in the design process along with a number of real-life factors that complicate the stackups.

Two Cummins B5.9L engines were fueled with 100% biodiesel in excess of 48 months by the Agricultural Engineering Department at the University of Missouri-Columbia. The engines used to power Dodge pickups. The engine lubricating oil was sampled at 1000 mile intervals for analysis. Statistical analysis of the engine lubricating oil indicated that the wear metal levels in the lubricating oil were normal. A reduction in power was noted when the engines were tested using a chassis dynamometer. The 1991 pickup has been driven 110,451 km and the 1992 pickup has been driven approximately 177,022 km. The pickups averaged 6.9 km/L. Engine fuel efficiency and material compatibility issues are addressed in the paper.

In this paper, the system identification theory and method using dynamic neural networks are presented, the multilayer feedforward networks employed, the backpropagation with adaptive learning rate algorithms proposed. Finally the comparision of network output with that of the hydrostatic drive system of secondary regulation is given, and output error, sum-squared error et al, or the results that embody the effect of system identification given sine input to it are provided.

The usage of personal computers by members of The Maintenance Council of the American Trucking Associations has been measured through primary market research. Survey results indicate that maintenance management utilization of personal computers is significant and can be expected to continue to grow over the next several years. The computer platform is relatively new and includes peripherals such as communications modems and CD-ROM. Applications most prevalent today are office management and personal productivity packages. Future demand is for more vertical software specific to maintenance training, diagnostics and management.

As modern vehicular applications demand higher power density gears, accurate analytical tools to predict gear stress are required. The finite element method has been successfully applied to the analysis and design of components and structures of a vehicle. However, it is still difficult to apply to gears due to very complicated geometry, especially in the root fillet area. Since a good knowledge of the gear root geometry is required to calculate bending stress, the purpose of this paper is to present the root fillet geometry of spur, helical, spiral bevel, and hypoid gears. The gear root fillet equations are derived based on the simulation of cutting tool motion on the gear blank during the manufacturing process. For spur and helical gears, the root fillet geometry cut by a rack with and without cutter tip radius is discussed. The phenomenon of undercut is discussed as well.

In July of 1997, GM will introduce a Police Pursuit Sport Utility to the law enforcement market. The vehicle is based on the popular Chevrolet Tahoe full- size, four-door utility truck that was introduced in 1996. It is shorter than the Suburban and available in only a two-wheel drive version for the Police Pursuit Vehicle (P.P.V.) program. This vehicle replaced the now canceled Chevrolet Caprice, which traditionally had been developed to be a P.P.V. It created a new market niche with its unique size and features. The combination of using proven, existing components and following an aggressive testing schedule allowed GM to develop this unique new product in a 48-week time frame, a relatively short development time for such a challenging program. The GM Truck Group used proven technology on this program.

Operational Deflection Shapes (ODS) analysis has been in existence for more than 20 years, but has been overshadowed by its progenitor, Modal analysis. This paper describes how and why ODS analysis was applied to the development of the GMTG T-series Medium Duty Truck and presents some examples of the results obtained.

Rear end break-away, or skate, is a phenomenon that occurs when live axle equipped vehicles are driven aggressively on rough, winding roads. This paper reviews instrumented dynamic testing of a specially built vehicle. Initial testing linked skate to the tramp oscillation mode of the rear axle. Two variables were evaluated for reducing skate: shock absorber valving and shock absorber placement. The principal conclusion of this work is that although some reductions in skate are possible by adjusting shock absorber valving, optimum control of skate is facilitated by packaging the shock absorbers near the wheels.

SAE research into the ISO 14000 series of standards offers insights into the opinions and attitudes of the experts, U.S. industry leaders and government representatives. A series of focus groups with industry leaders, in-depth interviews and a review of secondary research data, provide a perspective on the ISO 14000 series as it is understood on the eve of acceptance by the international community. This research study, sponsored by SAE, explores reactions to both the early components of the standard (14001 and environmental management systems scheduled to be adopted in the summer of 1996) and those portions of the standard still being developed which relate more specifically to product components and the global standardization of life cycle analysis and eco-labeling.

Environmental concerns over disposable oil filters impact engine oil filter selection for over-the-road trucks and buses. Fleets are extending oil drain intervals and considering alternatives to traditional spin-on filters in an attempt to reduce the costs associated with filter service and disposal. Alternatives to spin-ons, such as screen type separators, are inadequate in terms of particle removal efficiency and contaminant holding capacity. Further, these alternatives typically cost 20 to 40 times more than spin-on filters and are difficult to service. This paper discusses a new line of cleanable, high performance spin-on oil filters. Laboratory tests show that these reusable filters meet or exceed efficiency and capacity specifications set by engine manufacturers. These filters can be cleaned at the normally scheduled service interval without special tools and without removing the filter from the engine.

The development of a particulate filter for a motor vehicle ventilation system is based on filter performance requirements, vehicle's operational environment, available space, filter media properties, and filter element technology. The design process includes analyses of theoretical and empirical models describing filter media performance and aerosol flow in filter housings and through filter elements. Filter media are carefully selected based upon these models and simplified laboratory tests. The filter element design is evaluated in great detail through a series of laboratory and field experiments. This paper shows the process of cabin filter design, including filter media selection and experimental evaluation. Four recently published ISO and SAE test methods are discussed in detail. One of them, the SAE J1669 test procedure, was used to determine full scale filter element performance characteristics.

In the late 1980s engine coolant recycling technologies were developed in response to a temporary but significant increase in the cost of ethylene glycol. Among these technologies was the adaptation of reverse osmosis water desalination processes by Stanadyne Automotive Corp.1 The technical paper describing the reverse osmosis (R/O) technology reports that the process efficiently recovers ethylene glycol and water in a sufficiently pure state to allow its use as a base fluid to reblend into engine coolant. Data generated in standard ASTM bench tests has demonstrated the capability of properly reinhibited R/O recycled engine coolant (ROREC) to comply with the performance requirements of accepted SAE, TMC, ASTM and OEM specifications. The technology has been applied commercially and this paper reports the operating experience of 15 users in Texas and California with diverse service applications. The experience has been very good.

The use of tridem axle groups for heavy commercial trailers was spawned by the Roads and Transportation Association of Canada (RTAC) research of the 1980s and is now commonplace on semi-trailers and B-trains in Canada. The Western Canadian log transportation sector employs a number of industry-specific configurations that are fundamentally different in design and operation to those studied in the RTAC research. Over the last decade, this sector has met the challenge to improve productivity by adding more axles to the trailing system of the traditional 5-axle tractor/pole trailer combination. Although productivity gains were realized with the addition of more trailing axles, both dynamic performance and vehicle mobility were reduced. Where tridem axle groups are used as an alternative to the multi-articulated three and four axle trailer assemblies, dynamic stability is improved and where tridem drive axle groups are used, mobility is also improved.

The 1997 Ford Explorer introduces a new two valve single overhead cam (SOHC) version of the 4.0L V6 engine. Maximum power output is increased to 153 KW net (205 HP) at 5000 rpm and 340 N-M of torque (250 lb-ft) at 3000 rpm, which represents a 28% increase in power and an 11% increase in torque over the existing 4.0L overhead valve (OHV) design. The new design's performance features are single overhead camshafts driven by a patented “Offset Y-drive” dual stage chain system, a plastic variable induction system, and aluminum cylinder heads. For quieter and smoother operation, a main bearing ladder frame and a unique second-order balance shaft (4x4 only) are added.