Search Results

Hydraulically actuated, friction disc type couplings are capable of being utilized as direct drive limited slip devices for use on auxiliary drive axles. These couplings can be excited to function at wheel speed Δn levels due to their high torque transfer density and high torque transfer capacity. The utilization of these hydraulic couplings eliminates the need for torque multiplication through speed reduction. The common differential element is replaced by two independent, but communicating couplings to facilitate direct drive of the wheels on the auxiliary axle. The arrangement described in this paper provides a built in limited slip differential (LSD) effect as well as a simple and powerful all wheel drive (AWD) system. This paper will compare the performances of such systems with classic architectures under various driving conditions.

This paper describes the design and features of the 1998 Ranger Pulse Vacuum Hublock (or PVH) 4x4 system. This part-time 4x4 system with wheel-end disconnect offers optimized fuel economy in a robust design that requires no regularly scheduled maintenance under normal driving conditions. The system allows silent 4WD shift on the fly at any speed or temperature and does not require reversing the vehicle to disengage the hublocks.

The automotive pressure sensor is one of the most widespread applications of a micromachined device, and has evolved into a relatively mature technology, expanding beyond its original use as an engine control sensor into other vehicle control and diagnostic systems. The need for flexibility in various applications, low cost, high volume manufacturing capability, and survivability in harsh environments has strongly influenced sensor signal conditioning, calibration, element design, and packaging. Many of the issues affecting the development and commercialization of micromachined automotive pressure sensors are also relevant to other emerging microfabricated devices. This paper shows how the commercial success of a product using microfabricated technology is highly dependent upon other core competencies, beyond just the capability to perform the micromachining operations necessary to create the sensing device.

A new sensing technology has been developed by the U.S. Department of Energy that makes possible non-mechanical means of position sensing, fluid level measurement, occupant sensing, distance measurement, and materials analysis. This technology is called Micropowered Impulse Radar or MIR. MIR technology can be used for direct measurements using a probe, or remote measurements with an antenna. Although many new and unique sensor applications are possible using MIR, this paper covers the description, design and characteristics of a time domain reflectometer (TDR) fuel/fluid level sensor using MIR technology. A comparison with other non-mechanical fuel level measurement technologies will be made.

Optimization techniques can be applied to synthesize the design of automotive systems and components to meet product requirements. In this paper, the performance of two automotive designs - a rear suspension system and a clip shape - was improved by using optimization techniques. For each design, calculation of the performance indices and the formulation of the optimization problem are discussed.

New Venture Gear developed an innovative torque transfer system that simplifies transfer case design. An external single actuator controls an automatic, dual-gear ratio transfer case. This single actuator design provides torque transfer to the front axle when it meets certain conditions. It makes shifting to a different gear ratio possible without the use of an additional actuator or mechanical lever.

The United States Federal Motor Vehicle Safety Standards were amended in 1975 requiring Anti-Lock Braking Systems (ABS) to be installed on nearly all buses, coaches and motorhomes operated within the U.S. This paper reviews ABS operation and the components required for typical ABS installations. Recommendations for the ABS configuration most appropriate for common North American bus, coach and motorhome chassis, drivetrain, and suspension combinations are provided. Automatic Traction Control (ATC), an optional enhancement available with ABS, is also discussed. Application issues of integrating ABS/ATC with the electronically controlled engines, transmissions, retarders and air suspensions commonly applied on North American buses coaches and motorhomes are described.

As some of today's bus industry is moving toward electrically powered, low-emission buses, very compact drivetrain package, the driveline design which links electrical motor to spiral bevel or hypoid gears can become a significant challenge especially under severe environment and certain design constraints. The drive axle layout under consideration is depicted in the Figure 1. A design that have an integral shaft extended from cone apex (narrow end) of the pinion to connect to electrical motor is considered. In this design the undercut situation of the shaft by cutter tip during gear tooth generation becomes very critical. The purpose of this paper is to study the effect of cutter radius to provide a solution which is able to avoid or alleviate the interference condition and/or to determine undercut-free shaft diameter and location.

The Vehicle Data Acquisition Project was started to fulfill a desire at Horton Vehicle Components, Inc., to know more about the actual environment in which our products live. Operating under the hood of over-the-road vehicles produces some of the most demanding environmental conditions for any product's survival. Although our products are extensively tested in the laboratory mounted on diesel engines, it is not the same as inside a vehicle's engine compartment. A vehicle moves, stops, starts, pulls hard, bounces on the highway, idles and goes through different climates--and can do this all in the same day. These conditions would be impractical to duplicate in the laboratory. Also, this data should be collected over periods of time, perhaps as long as a year on the same vehicle. By doing this on different vehicles, a database can be developed that would allow comparisons across different vehicles, different seasons, or the same seasons but different years.

This paper describes a crash detection system developed for use in automotive passive restraint applications. The system is unique in that the small, rugged module performs all of the functions necessary to determine when airbag deployment is required. Because it is designed to be mounted near the impact zone, the system is well suited to three difficult crash discrimination situations: front impacts in body-on-frame vehicles such as light trucks, side impacts in any automobile, and crash severity discrimination for future adaptive restraint systems.

Engineering complex systems is challenged by problems of language, increasingly as systems become more complex. Prominent are (1) integration of subsystems using communication networks, and (2) integration of work of engineers, product planners, suppliers, and customers. Both “hard engineering” and “soft process” cases encounter some of the same language problems in different settings. This paper briefly notes aspects of the structure of language and meaning and how they relate to these system engineering contexts. A practical, model-based technique, the Protocol Information Model (PIM), is described, to integrate both “hard” engineered systems and “soft” work processes which use “shared communication channels”.

A case study of the application of optimization techniques to the design of rear-axles-connecting-linkage of heavy trucks with only two rear axles has been presented. The rear axles are made to move in tandem by designing a linkage connecting the two at each of its ends. The linkage locations are determined by the inter-axle-drive shaft, which is a telescopic tube. The drive-shaft is mounted with U-Joints on the two rear axles and follows the bumps and rebounds of the roads with minimal rotation about the lateral axis. Optimization techniques were applied to a planar ADAMS Model to minimize the drive shaft rotation.

Torsional rubber heavy vehicle suspensions have been used for over 60 years. The historical background makes an interesting engineering case study. A new simplified updated redesign of the system has been accomplished. It retains the long-life, relatively soft spring rate and roll stability advantages of the original design. Reduced adhesion stresses and a simplified vehicle leveling system are new advantages. Vehicle comparison testing with other suspension systems indicates significant improvement in ride comfort, stability and vibration reduction. Future designs will likely use new more sophisticated compression springs operating in combination with the torsional springs to further improve the ride.

Ride quality of medium truck became a very important factor in the suspension design, due to the demand of more comfortable ride of passengers. This study describes how to determine and evaluate design parameters related to the chassis suspension system with time and frequency analysis. The spring stiffness and damping force of the chassis suspension system were obtained by observing the vertical acceleration PSD. The simulation was carried out on various road profiles, which was suggested by ISO. The pitching motion of the medium size truck was observed to improve the ride quality. A computer simulated truck model was constructed using DADS, a commercial dynamic analysis software, in order to simulate the truck motions. From the result of the sensitivity analysis of suspension parameters, it was concluded that the spring and the shock absorbers affect the pitching of the vehicle. In order to validate the computer simulated truck model, a physical prototype was constructed and tested.

Several lead-free alloys have been studied for potential use in electronics by the National Center for Manufacturing Sciences(NCMS) Lead Free Solder Consortium that ended in 1996. Since then, one of these alloys has been studied using an existing product in order to determine the viability of Lead Free Vehicle Electronics. Design, supply chain, manufacturability, and reliability data for the electronics components and system are a part of this paper.

Hybrid electric transit vehicles offer many improvements over conventional diesel fueled buses through the application of new and emerging technologies not previously applied to the bus environment. However, these changes require the manufacturers of hybrid buses to go to great lengths to insure that the industry does not take a step backwards and end up burdened with unreliable vehicles which do not perform as advertised. This paper will describe Nova BUS's approach to developing a reliable hybrid electric transit bus through a comprehensive test and evaluation process. The substantial changes in technologies, drive train configurations and potential failure modes inherent in the design of hybrid vehicles require a fresh look at the way bus designs are tested and validated. The ultimate goal of this process is to provide a quality product to the market which offers the full range of advantages which are possible using hybrid technology.

Nearly all segments of the automotive business are actively involved in pollution reduction and environmental activities as a daily part of doing business. Environmental responsibility is a process of continuous improvement; a manufacturer never arrives at a point where further environmental activity is unnecessary. An environmental or “green” metric enables a manufacturer to measure and compare environmental performance over time and among alternative proposed product designs and manufacturing processes.

This paper addresses each of four phases regarding the life of electronic products including design, production, consumption, and end of life/recycling. It assesses each phase, its impact on the environment and relates them to ISO 14000 (International Standards Organization 14000 Environmental Management Systems: General Guidelines on Principles, Systems and Supporting Techniques).

The paper shows the completely new designed concept for electronics in the Mercedes-Benz Actros. The basic rules are explained, and on the example of the engine management the advantages of such an entire-vehicle promise are shown. At last it is pointed out, that the presented concept will be the basis for future developments on integration of electric's and electronics.

Rapid growth in the number of electronic systems on today's commercial vehicles has resulted in the proliferation of information displays. Systems for driver message centers, mobile communications, and fleet management are using flat panel displays for information management. Liquid crystal, vacuum fluorescent, and LED are commonly used display technologies. These devices are often segmented displays and are useful in presenting numeric or iconic data. Recent driver information systems have used multi-line character displays to present alphanumeric information. The use of a small graphic array display offers the benefit of presenting either alphanumeric or graphic information. Small graphic arrays that use liquid crystal technology are beginning to appear in vehicles. Graphic array displays using electroluminescent technology are also available.