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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.

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 stabilizer bar attachments problem can not be simply analyzed by using linear FEA methodology. The large deformation in the bushing, the elastic-plastic material property in the bushing retainer bracket, and the contact between different parts all add complexity to the problem and result in the need for an analysis method using a non-linear code, such as ABAQUS. The material properties of the bushing were experimentally determined and applied to the CAE model. It was found that using strains to estimate the fatigue life was more accurate and reliable than using stress. Many modeling techniques used in this analysis were able to improve analysis efficiency.

The electrical system of a commercial vehicle is a critical component for reliable vehicle operation. While the demands on today's electrical system have increased dramatically due to higher horsepower engine environments and increased key-off loads, the design of these systems continues to evolve in order to meet these demands. Unfortunately, this design evolution has not kept pace with user expectations for enhanced performance, durability and reduced maintenance of the electrical system. In support of the TMC's S.1 Tomorrow's Truck initiative, this paper offers the following vision of future alternator requirements that will fulfill the expectations of commercial vehicle drivers, maintenance and support personnel. The intent of this vision is that it be used by designers and vehicle manufacturers as a guideline of desirable features for the alternators of tomorrow's truck.

The 4M5 series of four-cylinder, in-line, direct-injection diesel engines has been released by Mitsubishi Motors Corporation for light and medium-duty trucks and buses. Featuring an updated structure and reflecting the employment of state-of-the-art technology in the design of every component, the new engine series offers high reliability and compact dimensions. Moreover, the new series well meets contemporary demands for high performance, low noise, and clean combustion.

Air spring systems are increasingly used on suspensions for commercial vehicles. To prove their durability a reliable test procedure is necessary: to be applied already in the development stage to be used to qualify individual air spring manufacturers and to assure manufacturing quality. In this paper the test procedure, the test facility and some test results are presented. In the test facility the air spring is mounted on a fixture and is loaded by a servohydraulic actuator. The mounting of the air spring allows to simulate all operational deformations, being decisive for the durability. Based on the extensive measurements on proving ground and public roads the test program was worked out. The test program includes besides the loading and deformations during driving also kneeling operations as well as high and low temperatures. The accelerated laboratory tests deliver results which correspond to the existing experience at the service usage.

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.

A new technique for an engineer to evaluate his own mechanical designs for reliability is being developed which supports the SAE Fault/Failure Analysis Procedure, ARP-926A in improving designs and reducing maintenance costs. The new technique brings the operating environment down to the part level where resulting stress levels can be identified for each part and compared to material properties. This process allows the user of ARP-926A, currently the most powerful procedure available for identifying and tracking failure modes, to more precisely determine the likelihood of occurrence for the identified failure modes of mechanical equipment.

Optimal trailer design for tractor-trailer transportation depends on accurate and reliable estimates of typical lifetime loading duty cycles. On-the-road testing was done to measure the vertical acceleration response of three different trailers in forest logging conditions. The test conditions included various trailer axle and load configurations, weight transported, and road surfaces including both gravel and paved roads. It was concluded that the rigid trailer body bounce and pitch, the non-rigid body trailer bending, and the wheel hop are the primary components of the vertical response. These results establish approximately what types of operational amplitudes are to be expected for these operations and will provide the basis for the development of a more general trailer frame load prediction model.

Fuel level sender technology has evolved from simplistic wire-wound resistive senders to more advanced and reliable methods. Many options now exist that can provide a form, fit, and function equivalent sender that improves reliability, accuracy, etc. Current trends are leading toward senders that have no moving parts and will function in a variety of tank sizes and shapes, rather than requiring a different sender for each tank. This leads to reduced inventory requirements at the OEM level but presents unique design challenges. This paper will concentrate on fuel level sensing, but will provide relevant data on measurement of other automotive parameters.

An electronic refrigerant management system has been developed which increases the reliability and performance of heavy duty vehicle air conditioning systems. The entire system is packaged in a single module which contains the sensors, electronics, and refrigerant flow control device. The system includes an SAE J1708 serial link and SAE/TMC J1587 documented fault codes for easy troubleshooting and system maintenance.

This paper will establish the fuel quality necessary for use as a modern CNG and/or LNG vehicular fuel which will accommodate efficient performance and low emissions. The premise of using either BTU content and/or Wobbe index as a reliable means of fuel quality identification for vehicular fuel will be explored and discounted. Standards for transportation grade LNG will be developed.

For commercial vehicles the availability of the truck has become increasingly important to the owner. Unexpected stops and visits to workshops are expensive nuisances not least if caused by some minor faults. The cab comfort and the vehicle response are fundamental to the driver. The accessibility and fault localizing are principal to the mechanic. The safety and the environmental impact are scrutinized by the authorities. The adaptability are vital to the dealers. The climate capability is needed to global presence and to long distance transports. Light weight structural solution permits heavy pay-loads. Low total usage cost is a must to be competitive. Advanced technology is implemented into the truck at increasing rate to satisfy all the aspects above. Quality has become the key issue to reach for the high standard demanded.

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.

Compressed air - as a working medium for brake systems of commercial vehicles - is generated by engine-driven, oil-lubricated compressors. New concepts of compressor control can reduce average power consumption by at least 1 kW up to 5 kW, realising savings of up to 5 % of fuel consumption. Additionally a significant increase of reliability and life time for subsequent parts and valves of the air brake system can be expected due to design improvements with lower temperature levels and reduced oil carryover. Thus reliability and safety of operation are increased. Light weight design can save up to 10kg, respectively 50% of traditional compressor weight.

Fatigue life estimates of automotive structures are often obtained using stress estimated from static solution methods such as inertia relief [1, 2]. This approach can provide reliable results if the natural frequencies of the system are at least twice that of the highest loading frequency. Direct and modal transient fatigue approaches would include dynamic effects but are not practical due to increased computer resource requirements. This paper outlines a modified modal superposition based transient method. In this method, modal stress is obtained using a commercial FEA code. The transient solution is then obtained externally to significantly reduce computer requirements. Additionally, a numerical procedure is outlined which is capable of incorporating non-zero initial conditions for increased accuracy.

A new foundation brake, the CamLaster ™, is being introduced into the North American heavy truck market. This new product is one of the first new drum brake designs in over 20 years. It promises to address many of the trucking industries major concerns for improved reliability, ease of maintenance and long service life. The product was a joint development of Freightliner and ArvinMeritor. The brake took over 6 years to develop and bring to market. Multiple design groups in North America and Europe were involved in the development. This paper discusses the engineering program from market research to production.

Nearly every area of vehicle electronics is experiencing a design and implementation revolution. Drive-by-wire concepts, controller area networks, and “on-line” information systems are rapidly changing the way we view vehicle electronics. Advancements in technology enable improvements or even revolutionary changes in the way products are designed. Enhancements in semiconductor technology are enabling an evolutionary change in the design of products for all types of vehicles. Electrical systems are supporting the movement towards higher voltages, more features, and more power. Today, heavy duty signaling applications may have as many as 20 bulbs connected to the flasher, forcing designers to look towards higher reliability, solid state switching methods.

This paper presents, in a case study format, a methodology for combining the methods of Design of Experiments, Accelerated Testing, and Weibull Analysis to improve the reliability of an ABS Electronics Control Unit (ECU). While much literature focuses on each method individually, sometimes it's necessary combine all of these methods to achieve product improvement. The paper walks through the steps of using an multi-environment over-stress accelerated test routine, with DOE methods to evaluate key factors, and then applying Weibull and Weibayes methods to validate the new proposal and estimate expect life improvement.

Allison Transmission has been a key player in the Military and Heavy Duty Commercial truck markets for many years. These tough vocations require transmissions that are not only capable of heavy loads, rigorous duty cycles, and proven reliability, but also provide value for the end-user and maintain compatibility with leading edge technological improvements of engines and other parts of the vehicle system. The Allison HD4070 transmission is one of the latest transmission offerings from Allison Transmission to meet the “next generation” heavy-duty vehicle needs. This product increases value to the vehicle manufacturer and customer, and provides compatibility with the fast changing electronics capabilities of modern vehicle systems and engines. These improvements are offered in a durable design that has been the trademark of Allison transmissions in these markets.