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Cyclic oligomers of butylene terephthalate (CBT™)† represent a new chemical route to semi-crystalline thermoplastic polybutylene terephthalate (PBT). The oligomers of interest melt completely at about 150°C to produce a low viscosity fluid that is ideal for wetting and dispersing fibrous fillers and reinforcements thereby enabling the development of composites that were previously not possible when working with high viscosity commercial PBT. Introduction of catalyst to undiluted molten cyclic oligomer leads to rapid ring opening polymerization and the formation of high molecular weight thermoplastic PBT without the generation of volatile organic compounds. The polymer resulting from this polymerization will be hereby referred to as pCBT. Treatment of cyclic oligomers in this fashion results in pCBT thermoplastic resin with a high melting point (230°C) and physical performance similar to that of other commercially available PBT resins.

The coupling is an integral part of the Cummins CELECT electronically controlled injector. Excessive wear was observed on early designs of the coupling and coupling bore. The coupling wear was caused by a high stress concentration and excessive side loading of the coupling as it slid against the coupling bore. The zero wear theory was used to develop a coupling design where the maximum wear depth does not exceed half the peak to peak surface finish (zero wear) over the life of the engine. The side load exerted on the coupling was compared with the calculated contact pressure for zero wear. The undesirable effects of a square edge stress concentration are discussed in the zero wear model. The physical effects of the sharp edge and chamfered coupling edge are reported, but not analyzed in this paper. Three different coupling designs were investigated by applying the zero wear concept.

The hazardous bulk chemical liquid cargo transportation is usually made through highways, using special automotive devices, named semitrailer tank, a kind of mobile tank specially developed to perform this task, manufactured with many types of steel, selected according to the chemical characteristics of the product to be transported. Equipment sizing is made based on specific standards which include specified formulas, loading, and safety factors representing the design criteria of this type of device. Despite of the detailed design criteria for semitrailer tank, it has been observed failure of some pieces of equipment during operation, in a shorter effective life than that one considered in the design phase itself. Considering a detailed study of the stress distribution in this type of equipment, this paper shows a verification of the possibility of yielding failure in the semitrailer tank structure.

This paper will discuss Concurrent Engineering as an emerging product development methodology. Specific emphasis will be placed on some of the key tools and considerations necessary for the success of Concurrent Engineering. In particular, the paper will discuss strategic product planning driven by customer requirements and how the product development effort will support the strategic product plan.

All around the world, steps are being taken to improve the quality of our environment. Prominent among these are the definition, implementation, and attainment of increasingly stringent emissions regulations for all types of engines, including off-highway diesels. These rigorous regulations have driven use of technologies like after-treatment, advanced air systems, and advanced fuel systems. Fuel dispensed off-highway is routinely and significantly dirtier than fuel from on-highway outlets. Furthermore, fuels used in developing countries can be up to 30 times dirtier than the average fuels in North America. Poor fuel cleanliness, coupled with the higher pressures and performance demands of modern fuel systems, create life challenges greater than encountered with cleaner fuels. This can result in costly disruption of operations, loss of productivity, and customer dissatisfaction in the off-highway market.

Work solenoids are widely used in household appliances. The environment and design of this type application does not lead to solenoids for the earthmoving industry. This paper presents the environmental effects to be considered when designing a solenoid for the earthmoving industry. It further explains the need for, and type of, test necessary to validate the design. Finally a review of production quality procedures, necessary to insure reliable production parts is discussed.

This SAE Standard specifies requirements and design guidelines for electrical wiring systems of less than 50 V and cable diameters from 0.8 to 19 mm2 used on off-road, self-propelled earthmoving machines as defined in SAE J1116 and agricultural tractors as defined in ASAE S390.

This SAE Standard specifies requirements and design guidelines for electrical wiring systems of less than 50 V and cable diameters from 0.35 to 19 mm2 used on off-road, self-propelled earthmoving machines as defined in SAE J1116 and agricultural tractors as defined in ASAE S390.

This SAE Standard specifies requirements and design guidelines for electrical wiring systems of less than 50 V and cable diameters from 0.35 to 19 mm2 used on off-road, self-propelled earthmoving machines as defined in SAE J1116 and agricultural tractors as defined in ASAE S390.

This report is concerned with the effects of braid angle on the behavior of hydraulic hose. For equilibrium conditions to exist, and if the braid layers are assumed to bear tension forces only, the angle of the reinforcement layers must be along that of the total force exerted by the internal pressure. This is the neutral angle θN, which has a theoretical value of 54.74° (54°44′). It is possible to hypothesize a fretting wear model in which wires move on top of one another inside a braid layer if the braid angle is different from this theoretical neutral angle. Even though theoretical claims are made by some technical professionals, the hydraulic hose industry has been successfully making hoses with non-neutral braid angles for years. Testing and application have shown that fretting wear is not a principal cause of hose failure and fatigue.

The development trend in construction machinery has been to produce equipment having a high level of reliability. The dollar loss that occurs when a major piece of equipment breaks down on the job is sufficiently great to justify the cost of providing reliable operation. In the development of the North the need for increased reliability is greater than ever. In extreme low temperature conditions as found on the NORTH SLOPE operation in Alaska, the harshness of the environment places additional stress both on the equipment and the operators. The development of winterization kits for construction and heavy engineering equipment to date has been slow, probably because of a comparatively small market and because the work could be postponed or accomplished by protecting the equipment and operator by temporary means to meet the purpose. The results have not been economical or as efficient as desired but efficient enough to be acceptable.

SINCE 1954 the CIMTC Subcommittee has been engaged in a program to meet military requirements through industry's production of construction equipment which can give satisfactory cold weather performance down to temperatures of −65 F. Individual contracts for three crawler tractors and one motor grader were negotiated by ERDL for these projects, and their performance is discussed. Industry participation was subsequently expanded to include engineering tests in the cold weather conditions of the Mesabi Iron Range. This joint report of the Winterization Sub-committee of the CIMTC and ERDL Winterization Section consists of separate papers by various members and consultants of this Sub-committee and ERDL personnel.

To investigate the feasibility of various test procedures to determine aerodynamic performance for the Phase 2 Greenhouse Gas (GHG) Regulations for Heavy-Duty Vehicles in the United States, the US Environmental Protection Agency commissioned, through Southwest Research Institute, constant-speed torque tests of several heavy-duty tractors matched to a conventional 53-foot dry-van trailer. Torque was measured at the transmission output shaft and, for most tests, also on each of the drive wheels. Air speed was measured onboard the vehicle, and wind conditions were measured using a weather station placed along the road side. Tests were performed on a rural road in Texas. Measuring wind-averaged drag from on-road tests has historically been a challenge. By collecting data in various wind conditions at multiple speeds over multiple days, a regression-based method was developed to estimate wind-averaged drag with a low precision error for multiple tractor-trailer combinations.

A 1:10-scale wind tunnel development program was undertaken by the National Research Council of Canada and Airshield Inc. in 1994 to develop trailer side skirts that would reduce the aerodynamic drag of single and tandem trailers. Additionally, a second wind tunnel program was performed by the NRC to evaluate the fuel-saving performance of boat-tail panels when used in conjunction with the skirt-equipped single and tandem trailers. Side skirts on tandem, 8.2-m-long trailers (all model dimensions converted to full scale) were found to reduce the wind-averaged drag coefficient at 105 km/h (65 mi/h) by 0.0758. The front pair of skirts alone produced 75% of the total drag reduction from both sets of skirts and the rear pair alone produced 40% of that from both pairs. The sum of the drag reductions from front and rear skirts separately was 115% of that when both sets were fitted, suggesting an interaction between both.

A wind tunnel experiment has been conducted to determine the changes in drag and side force due to the presence and position of cab extenders on a model of a commercial tractor-trailer truck. The geometric variables investigated are the cab extenders angle of incidence, the tractor-trailer spacing and the yaw angle of the vehicle. Three cab extender angles were tested-0°, 15° (out) and -15° (in) with respect to the side of the tractor. The cab and trailer models have the same width and height. The minimum drag coefficient was found for the tractor and trailer combination when the cab extenders were set to 0° angle of incidence with respect to the headwind. This result holds for all yaw angles with moderate gap spacing between the tractor and trailer. This study suggests that commercial tractor-trailer trucks can benefit from adjustable cab extender settings; 0° when using a trailer and -15° when no trailer is used.

The use of devices to reduce aerodynamic drag on large trailers and save fuel in long-haul, over-the-road freight operations has spurred innovation and prompted some trucking fleets to use them in combinations to achieve even greater gains in fuel-efficiency. This paper examines aerodynamic performance and potential drag reduction benefits of using trailer aerodynamic components in combinations based upon wind tunnel test data. Representations of SmartWay-verified trailer aerodynamic components were tested on a one-eighth scale model of a class 8 sleeper tractor and a fifty three foot, van trailer model. The open-jet wind tunnel employed a rolling floor to reduce floor boundary layer interference. The drag impacts of aerodynamic packages are evaluated for both van and refrigerated trailers. Additionally, the interactions between individual aerodynamic devices is investigated.

The trucking industry is being encouraged by environmental and cost factors to improve fuel efficiency. One factor that affects fuel efficiency is the aerodynamic design of the vehicles; that is, the vehicles with lower aerodynamic drag will get better mileage, reducing carbon emissions and reducing costs through lower fuel usage. A significant tool towards developing vehicles with lower drag is the wind tunnel. The automobile industry has made great improvements in fuel efficiency by using wind tunnels to determine the best designs to achieve lower drag. Those wind tunnels are not optimum for testing the larger, longer heavy trucks since the wind tunnels are smaller than needed. The estimated costs for a heavy truck wind tunnel based on automotive wind tunnel technology are quite high. A potential nozzle concept to reduce wind tunnel cost and several other new possible approaches to lower wind tunnel costs are presented.

Cast iron is generally thought of as a weak, dirty, cheap, brittle material that does not have a place in applications requiring high strength and defined engineering properties. While gray cast iron is relatively brittle by comparison with steel, ductile iron is not. In fact, ductile iron has strengths and toughness very similar to steel and the machinability advantages make an attractive opportunity for significant cost reductions. Gray and ductile iron bar stock is commercially available and can be used as a direct replacement in applications that are currently being made from carbon steel bar. Ductile iron bar stock conversions are very prevalent in many fluid power applications including glands and rod guides, cylinders, hydrostatic transmission barrels and in high-pressure manifolds. Automotive gears are being converted to ductile iron for its damping capacity and cost reductions.

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In selecting springs for commercial vehicles, it is essential to consider the fundamental principles of the suspension system as a whole, as well as the specific spring characteristics. This paper discusses the applications of these principles; also, it compares the many types of springs available, including single leaf, multileaf, and two-stage leaf springs, and coil, rubber, and pneumatic springs. Among the considerations stressed are: the relationships of spring static deflections to vehicle pitch frequency and oscillation center location, the questionability of two-stage leaf springs, the disadvantages of single tapered leaf versus multi-leaf springs, the advantages of coil springs in low weight and variable rate, and why pneumatic springs are ideal for large load range, heavy commercial vehicles.