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Eaton has been working on technologies for cost effective, reliable and safe Automated Mechanical Transmissions (AMTs) since the mid 1970's. The company has introduced three different systems since the late 1980's, but all three systems were constrained by the lack of precise engine speed control during shifting. With the advent of electronic engine controls the constraint has been removed and precise engine speed control during shifting can be easily accomplished. The result is a simplified system that is powerfully intelligent and fully capable of automatic shifting i.e., the transmission system determines when to shift and executes the shift without any driver inducement across the broad spectrum of truck usage. This paper discusses some of the AMTs available to the truck market, showing how the system benefits both the OEM and the end user.

Basic lead-acid battery technology has remained virtually unchanged for almost 100 years. Although improvements have been made in chemistry and construction, the common causes that promote battery failure have remained the same. These causes are the result of sulfation buildup (crystallized sulfur molecules) on the battery plates. The most effective solution to this problem is pulse technology. Pulse technology helps eliminate battery failure by maintaining a higher active material processing area while creating a more consistent charge acceptance environment within the battery. As a result, productivity is improved, replacement and other battery-related expenses are avoided, and unnecessary negative environmental impact is averted.

An innovative Power Line Carrier (PLC) Communication system for video and digitally signal processed data distribution using the existing DC copper wire is presented. The major contribution consists of a new signal coupler that achieves a stable transmission bandwidth on the DC electrical lines. Several weeks of continuous beta tests achieved video transmission on the trucks +12V wiring (from the back of the truck to the driver's cabinet) and product manufacturing and delivery has started. Benefits include: simplicity of application; ease of implementation; effectiveness with video and data; applicability to all application types; elimination of coax and twisted pair wiring and its maintenance.

Use of power line technology is desirable for communication on vehicles, since it allows communication without adding wiring complexity beyond that provided by the electrical system, and furthermore allows easy retrofits. In some cases, mixed media systems may be optimal.

Multiplexed buses are necessary to add new electronic control systems on-board vehicles. With roughly 50% of these systems expected to be installed or modified after the vehicle rolls off the assembly line, plug-and-play retrofits are important. Using a network protocol that runs on the electrical wiring in a vehicle reduces wiring for new vehicles. In allowing use of wiring already installed on the vehicle, such a scheme also pays excellent dividends for retrofits. Over the life of a vehicle, networked electronic devices and sub-systems will be obtained from several different suppliers. Standard device profiles and a common network operating system are essential for their easy integration, whether on the assembly line or in the aftermarket.

A technique to compute vehicle weight (GVW or GCW) solely from measurements of force and acceleration taken onboard the tractor is described. A means to measure both variables by a single inexpensive sensor is disclosed, and algorithms are presented. Methods to compensate for real-world variables such as wind and grade are discussed, as are results obtained during 20,000 Km of testing. A potential means to determine GCW onboard the tractor without any additional hardware is presented. Applications, including ITS, are discussed, as are methods for instantaneous calibration.

The sounds traditionally used as auditory displays and warnings in truck cabs have no meaning outside the context of the particular environment in which they are used. If an operator changes equipment, often an entirely new set of warnings and the associations between the various sounds and the situations to which they refer must be learned, while at the same time long-standing associations learned from previous experience must be overcome. Furthermore, research has shown that people operating complex systems can effectively differentiate only five or six different alarm or warning sounds. In an attempt to overcome these shortcomings, a new class of auditory display, referred to as auditory icons, is being investigated. Whereas conventional auditory displays are defined by their particular acoustic parameters, auditory icons are caricatures of naturally occurring sounds. Such sounds are representational in that they have stereotypical meanings across large portions of the population.

Radar based collision warning systems (CWS) for heavy trucks have been in production and on the road in the United States for approximately two years. A short description of these systems is presented with actual driver performance data and accident reduction data as experienced by various U.S. national fleets using these systems. The next application of radar sensors is for Intelligent Cruise Control (ICC) or also known as Adaptive Cruise Control (ACC). This paper describes the operation of adaptive cruise control and presents the associated benefits to the driver The radar technology has been enhanced and the application has been extended to include radar controlled adaptive cruise control for heavy trucks This has been made possible by 1) technology improvements in radar systems, plus 2) the addition of the standard SAE J1939 data bus for engine controllers on most U.S diesel engines.

Caterpillar Fuel Systems is developing a family of next generation electronic unit injectors that provide the fundamental injection characteristics necessary for emissions and performance improvements for future direct-injection diesel engines. This paper describes the development and design of the mechanically actuated version of Caterpillar's advanced electronic unit injector fuel system to meet the engine customer driven requirements for enhanced injection characteristics with reliability and durability improvements.

The conventional diesel engine retarder is an add-on system that converts the power producing diesel engine into a power absorber by altering engine valve timing when vehicle retarding is desired. The retarding effect is achieved by releasing the compressed air charge near TDC compression to prevent energy from returning to the engine during expansion. Retarding performance is optimized only at one engine speed and the increased height due to the add-on approach is a disadvantage for some vehicle applications. This study introduces an integrated Variable Valve Timing (VVT) engine retarder (Figure 1) by applying the lost motion principle. The integrated retarding system has significant dimensional advantage over the conventional add-on engine retarder. The lost motion VVT retarder also provides optimized retarding performance over the entire engine operating range.

Although Hydrostatic Transmission System (HTS) had been used in many places, such as machine tools, agriculture machinery, construction machinery, and vehicles, it had not been used in good performance. Twenty years ago many people began to design new hydrostatic transmission with higher efficiency. Hydrostatic Energy Storage Transmission System (HESTS) is one of new hydrostatic transmission system with higher efficiency. HESTS is more fit for being used in vehicle that is always running in undulating ground or starting and braking frequently. Construction of vehicular HESTS was analyzed, mathematical model of vehicular HESTS was established. The needed control strategies of vehicular HESTS were analyzed because there are many variables would be controlled in the new transmission system.

A new method for detecting the low power conditions on electronically-controlled diesel engines used in on-road vehicles has been developed. The advantage of this method is that it uses readily available diagnostic tools and engine installed sensors with no necessity for a dynamometer test. Without removing the engine, it gives an estimate of the real engine power which is accurate to 5%.

A radically new approach to the design of bearings demonstrated feasibility in a U.S. Army SBIR1 program. It was first applied to universal joints on the HMMWV (High Mobility Multipurpose Wheeled Vehicle) in order to maximize the concept's performance benefits and optimize vehicle cost savings. The program2 was one of five recipients of the U.S. Army's 1995 SBIR Phase II Quality Awards. The concept has been issued three patents3. This paper presents the theory and documents HMMWV field test results in the successful development of a new universal joint with bearings that eliminate field lubrication and provide a major reduction in maintenance.

A generalized theoretical model of tire cornering properties is presented in steady state condition with lateral deflection of tread and complex deformation of carcass under consideration. The model is suitable for full range of vertical load and slip angle. Six parameters are defined to represent the characteristics of tire stiffness, contact pressure distribution and carcass deformation. The model is validated against test data. Some simplified models, e.g. brush model, HSRI model when longitudinal force is zero, Fiala model etc., can be derived as some specific cases of this model. The analytic model provides a sound foundation for semi-empirical expression and gains insight into study of vehicle system dynamics.

Based on the tire cornering properties in steady state condition, a theoretical model of non-steady state tire cornering properties (NSSTCP) with small lateral inputs is presented. The outputs of the model are lateral force and aligning moment, while the inputs are yaw angle and lateral displacement (or turn slip and slip angle). The deformation characteristics of contact patch are analyzed in non-steady state condition. The flexibility of tread and that of carcass are both taken into account. The deformation of carcass is assumed to compose of translating part, bending part and twisting part. The tests of NSSTCP including pure yaw motion and pure lateral motion are realized with step inputs of yaw angle and slip angle respectively and test data is then transformed into frequency domain. The model is validated through comparing the computational results with test frequency response.

The detailed analysis of the tire loading and the subsequent deformations under operational driving conditions is of great importance for the basic investigation of the functionability as well as for the input and verification of the computer simulation of tires. Such data are also required for the definition of mission profiles as well as for the derivation of programs for the durability approval. The principles for the measurement of global tire deformations by spring loaded deflection transducers arranged in-between the tire crown and the rim are described. By combination of those sensors with wheel force transducers the determined tire deformations are referred to the actual service loading conditions. The sensors and transducers are described and examples of field measurement on heavy truck tires under distinguished driving conditions are presented.

Performance measures such as static roll stability, rearward amplification and load transfer ratio are a means to assess the engineering performance of heavy vehicles and to support truck size and weight policy decisions. It was expected that, for a particular vehicle configuration, there would be some degree of correlation between the various performance attributes. For example, a relatively high static roll stability may be associated with a relatively low load transfer ratio, at least within a particular vehicle configuration. In terms of developing performance measures such correlations are of great significance because (i) the number of performance attributes requiring specification may be reduced and (ii) potential conflicts between performance criteria in different attributes may be avoided. This type of analysis has not been carried out before, and requires a large database of performance numerics in order to determine relationships between each of the performance attributes.

The objective of this paper is to describe a Class 8 heavy truck that the Virginia Tech Center for Transportation Research has modified and instrumented for use in evaluating Intelligent Transportation Systems (ITS) technologies. The truck is capable of recording a variety of data, both electronic and video, in real-time from a suite of sensors and cameras that have been inconspicuously mounted on the tractor. The tractor, trailer, and instrumentation package enable Virginia Tech to conduct commercial vehicle ITS research related to safety and human factors, and advanced vehicle control systems (AVCS). This paper will describe the instrumentation package, and address both general and specific types of research that can be performed using this truck.

Steady state non-linear cornering properties, giving the lateral slip to force characteristics of individual axles as result are determined from experimental data. The handling diagram of the vehicle combination facilitates an examination of any unstable steady state yaw response. The method offers a viable alternative to the traditional constant radius test. Axle data is derived using the bicycle model via measurements taken during handling manoeuvring while the magic tire formula is used for adaptation of measured axle data into mathematical representation. The results of axle data evaluation, using a semi-trailer combination, manoeuvring over high friction surface conditions are presented.

This paper describes an economical rear obstacle detection system that eliminates the tractor to trailer cable connection using infrared (IR) wireless communication. The Trailer Subsystem operates whenever power is applied to the trailer from the J560 power connector. The subsystem transmits Obstacle Detection information to the tractor via an IR transmitter. The Tractor Subsystem is activated when the vehicle is put in reverse. Thus the entire system is active only when the vehicle is backing. During operation this subsystem receives and decodes the transmitted signal from the trailer and determines what, if any, warnings should be given the operator.