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An Automatic Tire Inflation System (ATIS), specifically designed for use on commercial long haul trailers underwent complete testing and evaluation in 1993/1994.1 Testing and evaluation included a field test of a prototype system and a controlled laboratory evaluation of the Rotary Union which is the only component subject to wear. The testing of the prototype system indicated that design improvements were necessary before the system could be installed in fleet operations. The design improvements were completed and field installation of production ATIS began. The design improvements were intended to improve overall system durability, decrease installation time, to have less effect on the axle structure than the original design, implement the use of SAE or DOT Approved pressure components and increase overall dependability of the system. ATIS systems have now been developed and tested for most domestic trailer axle configurations.

An articulated vehicle suspension comprising a parallel combination of passive energy restoring and dissipative elements and a feedback controlled force generator is analyzed using H2 control synthesis. The active suspension schemes based on limited-state measurements are formulated to minimize a performance measure comprising ride quality, cargo safety, suspension and tire dynamic deflections, and power requirements. The ride quality and the dynamic wheel load performance characteristics of these suspension schemes are compared to those of a vehicle with an ideal active suspension and an “optimum” passive suspension to demonstrate the performance potentials of the proposed limited-measurement-based suspension schemes.

Usually, vehicles driven under different road conditions are subjected to various forces and moments. An uneven input force originating from road surface could be one of the major load affecting ride comfort or body vibration. In order to investigate the ride and handling characteristics of a tandem axle truck, a three dimensional mathematical model is developed, and the equations of motion for the proposed model with fourteen degrees-of-freedom are derived. Various numerical techniques are used to solve this complex matrix equation. A computer program, capable of vibration isolation and dynamic analysis of tandem-axle truck, is presented. The sensitivity analysis for the parameter variation of the simulation model is investigated and the overall effects of anti-roll bar is also examined.

Low-Earth orbiting (LEO) satellite communications technology offers a new alternative to track and monitor transportation assets to increase operating efficiency and enhance cargo security. The affordable, low-power VHF communications equipment and the global coverage of LEO satellites provide a solution for tracking and communicating with mobile assets such as trailers and cargo containers. With the successful launch of the first two satellites in April 1995, the ORBCOMM Network is the first commercial LEO system and will begin trailer tracking and vehicle monitoring services in 1996. This paper will describe the ORBCOMM satellite communications system and will discuss the tracking and monitoring services ORBCOMM will offer to the transportation industry.

Vehicle theft is a continuing problem for the global auto and truck consumer. With vehicle costs increasing, many commercial fleet operators and consumers have been frustrated with the effectiveness of present theft deterrent and vehicle recovery systems. With the advent of modern generation automotive electronics, a wide range of products which can render a vehicle immobile to an unauthorized intruder are now arriving on the market. This paper will discuss possible vehicle security architectures and provide designs for some of the key building blocks. Additionally, it will discuss the enhancements possible using ITS/IVIS (Intelligent Transportation Systems/In-Vehicle Information Systems) system concepts. The paper concludes with recommendations to facilitate deployment of effective systems.

Cargo theft is pervasive and increasing, encompassing costs of lost cargo and vehicles, insurance, and prevention costs ranging from private security forces to increased investment in truck and rail terminal facilities. To date, security design for trailers, containers, and railcars has been “low tech,” but new security options are emerging. New vehicle technology is not a panacea, however, and additions to vehicle capital costs must be carefully analyzed versus traditional process-oriented and facility-oriented theft monitoring and prevention measures.

Heavy duty trucks account for about 50 percent of the NOx burden in urban areas and consume about 20 percent of the national transportation fuel in the United States. There is a continuing need to reduce emissions and fuel consumption. Much of the focus of current work is on engine development as a stand-alone subsystem. While this has yielded impressive gains so far, further improvement in emissions or engine efficiency is unlikely in a cost effective manner. Consequently, an integrated approach looking at the whole powertrain is required. A computer model of the heavy duty truck system was built and evaluated. The model includes both conventional and hybrid powertrains. It uses a series of interacting sub-models for the vehicle, transmission, engine, exhaust aftertreatment and braking energy recovery/storage devices. A specified driving cycle is used to calculate the power requirements at the wheels and energy flow and inefficiencies throughout the drivetrain.

Most present on-board scales utilize a micro-processor based meter in a cab and one or more remote “transmitters” out near the load sensors. The transmitters each have a voltage to frequency converter to digitize the transducer data. A new generation of on-board scale electronics is being designed which utilizes a network for the remote transmitters. The new transmitters contain their own micro-computer and calibration data storage. Digital data is sent over the network to a “master controller” in the cab. The master provides a direct interface to an on-board computer.

Electronic controls continue to propagate on vehicles in the truck industry. Many people, including engineering design personnel, do not fully understand the design, development, test, and manufacturing process for electronics. This paper specifically reviews design and test techniques necessary to produce a reliable electronic package. Potential benefits of a superior mechanical package include ease of installation and service, simple manufacturing process techniques, and protection from surrounding environmental conditions.

A new heavy duty chassis-cab, i.e., “chassis”, for refuse applications, has been designed to improve the productivity of its operator while minimizing his or her physical efforts. The chassis has its operating compartment and controls arranged such that required operator's motions are productive. The chassis features minimize the operator's exertion and maximize his or her comfort, thereby reducing fatigue associated with an otherwise strenuous occupation. This product was developed utilizing a new, structured process involving discrete phases, checkpoints and teams.

The admissible gross weight for road tankers in Europe is increasingly being reduced and controlled more strictly. This article describes the development of a road tanker in co-operation with the dutch transport company Boerman transport based on an aramid fiber reinforced vinylester resin, its specifications, design and manufacture and the tests on this vehicle. The result of this development is a road tanker whose overall weight could be reduced by approx. 400 kg. This means that the cylindrical tank became more than 25% lighter. Overpressure, loading, unloading and driving tests were run with success. The test results suggest a still higher saving potential.

This paper presents a discussion of the Eaton VORAD Technologies Model EVT-200 Vehicle Collision Warning system and the data recording capabilities of that system. The vehicle data management system and the accident reconstruction data system are described. The paper further discusses driver and vehicle experience based on actual customer utilization of the only radar collision warning system in production and on the road. The components and the general operation the collision warning system are presented. In addition, the paper discusses driver and management experience and feedback from users of VORAD systems and Eaton VORAD systems which have accumulated over 225,000,000 miles of highway operation on approximately 2500 vehicles and driven by over 3000 professional drivers.

Meeting the challenges of today's competitive and customer oriented transportation environment requires quick actions. Navistar's Advanta Concept Truck was developed in a very short time period, barely two months from concept to show truck. A newly engineered model with a new technology engine and new interior contributed to the exciting product content. New technologies such as Solids Modeling and Rapid Prototyping made some of the features possible. Following several months of shows around the country, another challenge began. “Clones” and kit parts were made from the concept truck.

Truck and bus accidents result in several billion dollars of loss per year. The advanced warning and situation analysis that can be provided by Obstacle Detection Systems have been shown to have the potential to significantly reduce this loss. Ultrasonic detection technology has been applied to obstacle detection on this class of vehicles in short range and low relative velocity situations. Fleet field tests have shown that drivers, who generally expect perfect system performance, are the key to the successful expansion of the application of Obstacle Detection Devices.

Collision avoidance systems are being developed today as a result of growing industry and government interest in reducing accidents and human suffering. Successful deployment of new technologies depends upon careful management of the design issues. Numerous parameters must be considered in the development of blind spot detection systems, as with other ITS products, to ensure appropriate and continued use by the driver.

The pressure of the marketplace is to demand environmentally-friendly products. This is keenly felt in the bus industry whether the product is used commercially or for pupil transportation. One of the lead states to make the greatest resource commitment is California and Blue Bird Corporation, fulfilling its leadership role, has aided California in this struggle. To date two engine manufacturers have made outstanding contributions to the use of natural gas as an alternative fuel. Tecogen, Incorporated developed the General Motors 427 cu. in. V-8 into an alternative fuels engine that operated as naturally-aspirated as well as turbocharged. John Deere designed a state-of-the-art, fully-electronic 8.1L Powertech engine that is presently setting a new standard in performance and fuel economy. Fuel tankage and delivery systems cannot be neglected for their role in creating a successful product. Valves, regulators and fuel lines have all been developed for safety and good maintenance.

In order to achieve robust and reliable vehicle control system designs, it is important to follow strict testing methods. Most engineers are familiar with test requirements for individual components and devices used in a vehicle control system. Not only do the individual components need to be validated, but also the summation of all elements, including the system's software. There must exist specifications and testing requirements for the entire integrated system. The testing must be designed to validate the entire vehicle control system, so that it can deliver its intended function under a variety of operating environments, conditions and applications. System performance may be influenced by all of the other systems on the vehicle, such as type of: engine, transmission, foundation brakes, air systems, suspension, and retardation. While it is not possible to replicate all operating environments it is important to follow a plan which can effectively validate the system.

In July, 1992 The Environmental Protection Agency (EPA) issued its final rule of section 604 of the Clean Air Act Amendments of 1990. The rule limits the usage, production and servicing of air-conditioning systems using CFC-12 (R-12) and HCFC-22 (R-22) refrigerants. The purpose of this action is to limit the deterioration of the stratospheric ozone layer. The reduction of the ozone allows ultraviolet radiation, type-B (UV-B), to penetrate and project down onto the earth. The act will affect the fleet operator in ways that may not have yet been explored. Specifically, operators will be faced with spending thousands of dollars on technology, as an industry and as individuals, to facilitate the necessary air-conditioning system conversions to provide compliance with the law and comfort for passengers. The need to develop an acceptable R-12 retrofit program has become a reality. This paper will outline the techniques for a successful R-12 to R-134a refrigerant conversion.

Over twenty prototype hybrid buses and other commercial vehicles are currently being completed and deployed. These vehicles are primarily “series” hybrid vehicles which use electric motors for primary traction while internal combustion engines, or high-speed turbine engines connected to generators, supply some portion of the electric propulsion and battery recharge energy. Hybrid-electric vehicles have an electric energy storage system on board that influences the operation of the heat engine. The storage system design and level affect the vehicle emissions, electricity consumption, and fuel economy. Existing heavy-duty emissions test procedures require that the engine be tested over a transient cycle before it can be used in vehicles (over 26,000 lbs GVW). This paper describes current test procedures for assessing engine and vehicle emissions, and proposes techniques for evaluating engines used with hybrid-electric vehicle propulsion systems.

With the introduction of the AT545R, Allison Transmission completes its family of transmission integral retarders. These retarders, as an auxiliary braking system to vehicle service brakes, will now be available with all commercial on-highway and off-highway transmission models. The AT545R has a retarder located on the input side of the transmission that is designed for auxiliary braking for downhill speed control. This 160-hp retarder has a two-stage capacity that, in conjunction with selection of the appropriate gear ranges, can be used to tailor desired retardation performance to particular duty cycles. The design, development and performance of the AT545R are targeted for school busses and motorhomes, though many other users will find distinct vehicle control advantages with this low cost, compact retarder. The development from concept through production implementation will be discussed in this paper.