Search Results

This paper presents a multidimensional approach to the hydraulic components design by means of an open-source fluid dynamics code. A preliminary study of a basic geometry was carried out by simulating the efflux of an incompressible fluid through circular pipes. Both laminar and turbulent conditions were analyzed and the influence of the grid resolution and modeling settings were investigated. A qualitative description of the internal flow-field distribution, and a quantitative comparison of pressure and velocity profiles along the pipe axis were used to asses the multidimensional open-source code capabilities. Moreover the results were compared with the experimental measurements available in literature and with the theoretical trends which can be found in well-known literature fundamentals (Hagen-Poiseuille theory and Nikuradse interpolation). Further comparison was performed by using a commercial CFD code.

Environmental concerns and government regulations are factors that have led to an increased focus on fuel economy in the automotive industry. This paper identifies a method used to improve the efficiency of a front-wheel-drive (FWD) automatic transmission. In order to create improvements in large complex systems, it is key to have a large scope, to include as much of the system as possible. The approach taken in this work was to use Design for Six Sigma (DFSS) methodology. This was done to optimize as many of the front-wheel-drive transmission components as possible to increase robustness and efficiency. A focus of robustness, or consistency in torque transformation, is as important as the value of efficiency itself, because of the huge range of usage conditions. Therefore, it was necessary to find a solution of the best transmission component settings that would not depend on specific usage conditions such as temperatures, system pressures, or gear ratio.

In this study the finite element method is used to simulate a light truck multi-leaf spring system and its interaction with a driven axle, u-bolts, and interface brackets. In the first part of the study, a detailed 3-D FE model is statically loaded by fastener pre-tension to determine stress, strain, and contact pressure. The FE results are then compared and correlated to both strain gage and interface pressure measurements from vehicle hardware test. Irregular contact conditions between the axle seat and leaf spring are investigated using a design of experiments (DOE) approach for both convex and discrete step geometries. In the second part of the study, the system FE model is loaded by both fastener pre-tension and external wheel end loads in order to obtain the twist motion response. Torsional deflection, slip onset, and subsequent slip motion at the critical contact plane are calculated as a function of external load over a range of Coulomb friction coefficients.

A novel transmission has been designed, built, and tested utilizing a traction continuously variable drive and a planetary traction fixed ratio drive. This paper describes the design of the transmission both in terms of power flow concept and in new component construction. The continuously variable drive and planetary are combined in a scheme whereby three modes of power flow are meshed to provide a high continuously variable ratio range of more than 20:1 overall. Neutral and reverse are available with no additional hardware. The transmission was installed in a half ton pick-up truck for testing the concept as a high ratio vehicle transmission.

The proprietary CVT technology introduced at the 1991 SAE International Truck & Bus Meeting & Exposition in Chicago has subsequently gone through numerous design iterations and is currently in the second generation hardware stage. Ongoing optimization of the hardware has resulted in overall system performance which meets or exceeds initial predictions, thereby assuring suitability for all automotive applications.

An organic Rankine Bottoming cycle added to Diesel engines used for long-haul trucks has the potential of improving their peak fuel economy by up to 15% over a typical duty cycle. General Electric has developed a multi-vane rotary expander which has a measured isentropic brake efficiency of 80+% over a wide range of speed and power levels with organic working fluids. High cycle efficiency for design and off-design conditions is achieved with the multi-vane expander. The potential advantages of the multi-vane expander for the Diesel engine bottoming cycle include the elimination of a high speed gear box and the potential for over 80% isentropic engine efficiency. The multi-vane expander is a ruggedly built component running at Diesel engine speed. This paper describes the design and evaluation of a nominal 40 HP multi-vane expander for this application.

A new concept in conventional truck cab vibration isolation has been developed by Holland Neway International. The system provides a significant improvement in ride comfort for the truck cab occupants in the truck of the twenty-first century. The single point isolator incorporates inclined sleeve type air springs to achieve a very low natural frequency, typically 0.9 - 1.1 hertz. A unique variable geometry damping system is used in conjunction with the sleeve springs to allow the configuration to achieve significant improvements in vibration isolation. The passive variable geometry control operates essentially undamped until large displacement disturbances are encountered allowing maximum possible isolation performance. Since the isolator natural frequency occurs in a region where the human physiology is most tolerant of vibratory motion, a high level of ride comfort is achieved.

It is apparent that a new generator and regulator design is needed to supply the additional electrical loads and meet the requirements for durability, reliability, and environmental protection on earthmoving equipment. The author discusses the d-c and alternator type systems which have been used to supply electrical needs. A detailed analysis of the integral charging system is presented. This system overcomes many of the shortcomings of the present electrical systems and, because it has a minimum number of moving parts, it is potentially the most reliable charging system in use on heavy duty equipment.

For over a decade engine manufacturers have been pursuing alternative fuel strategies for vehicle powertrains. First came the discussion of fuel selection. Next, whether or not these alternative fuels can provide the utility offered by traditional diesel. Finally, the footrace of technology and hardware to provide utility, reliability and maintainability with the use of alternative fuels. Now the day has come where many alternative fuels are a practical reality. The body of this paper will discuss the utilization of natural gas as an alternative fuel. This paper targets the fleet operator in an effort to provide a single source of information in a concise format. A discussion of emission standards, engine operational strategies, component technology, fuel characteristics and the utility of using natural gas as a fuel will be addressed. The understanding of present and future engine development is of great importance to a successful fleet operation.

A system has been developed which fragments rock by high-pressure gas discharges near the point of ripper penetration of a rock formation. From development tests, it was demonstrated that the system markedly extends the rock fracturing performance of a D7 Caterpillar tractor. The paper is divided into three basic sections. First, a summary of the mathematical analyses and model testing of rock fracturing is presented. Next, the hardware design and development necessary to adapt the FARE principle to rock-ripping requirements is described. Finally, the results and evaluations of tests conducted at various limestone rock test sites are described.

Five geometrically similar bulldozer blades, ranging in width 6.45-77.2 in., were tested in four different soil types. Tests were run at low speed and a constant cutting depth equal to 20% of blade height. Horizontal and vertical soil forces, soil force moments, and travel distances were measured. An analysis of the test data is presented and a method of predicting the draft force of larger blades from tests on smaller scale models is proposed. Test equipment, instrumentation, and test technique are described.

To deter theft of off-highway equipment, manufacturers must look at more than just putting padlocks on units. Most security devices can be overcome in some manner, given enough time. It then becomes a matter of establishing identification of the unit and determining rightful ownership. This requires having an identification number that is unique for each unit which can be readily found. If the primary identification number has been removed, a cross-check of component identification is needed. In addition, the owner must have some form of proof of ownership that cannot be copied or counterfeited.

The test procedure applies to roll coupled units such as straight trucks, tractor semitrailers, full trailers, B-trains, etc. The test is aimed at evaluating the level of lateral acceleration required to rollover a vehicle or a roll-coupled unit of a vehicle in a steady turning situation. Transient, vibratory, or dynamic rollover situations are not simulated by this test. Furthermore, the accuracy of the test decreases as the tilt angle increases, although this is a small effect at the levels of tilt angle used in testing heavy trucks. The test accuracy is accepted for vehicles that will rollover at lateral acceleration levels below 0.5 g corresponding to a tilt table angle of less than approximately 27 degrees. Even so, the results for heavy trucks with rollover thresholds greater than 0.5 g could be used for comparing their relative static roll stability.

The basic performance characteristics of greatest interest are airflow restriction or pressure drop, dust collection efficiency, dust capacity, and air cleaner structural integrity. This test code therefore adresses itself to the measurement of these parameters.

Data from this procedure permits mapping axle efficiency and/or waste energy over the operating range of passenger cars, trucks, busses, and other highway vehicles to which axles are applied.

Data from this procedure permit mapping axle efficiency and/or waste energy over the operating range of passenger cars, trucks, busses, and other highway vehicles.

The present work has the objective to quantify and evaluate abrasive wear resistance of a hard coating. It is obtained by weld deposition of an iron based alloy containing Cr and Nb as carbide forming elements, and to compare it to wear resistance of a heat treated SAE 5160 steel, normally used for agricultural equipment. Wear resistance was determined from two body and a three body abrasion tests using pin abrasion test equipment and a rubber wheel abrasion test, respectively.

International Truck & Engine produces vehicles that are often customized by TEMs (truck equipment manufacturers) and dealers as part of the body-chassis integration. International Truck & Engine developed a multiplexed control system that helps customization by allowing the vehicle electronics programming to be assembled using pre-packaged software modules. Because the system uses SAE standard networking, it is also simple to add devices to provide additional inputs and outputs. International Truck & Engine IT developed supporting business systems to handle the customization from order to delivery and track software per vehicle for service. However, dealers and TEMs often desire a higher level of electronics customization than can be easily delivered by off the shelf programming. While different software packages could be developed by International Truck & Engine engineering to support various needs, the proliferation of functionality is costly to manage, maintain and warranty.

The scope of this SAE Standard is the definition of the functional, environmental, and life cycle test requirements for electrically operated backup alarm devices primarily intended for use on off-road, self-propelled work machines as defined by SAE J1116 (limited to categories of (1) construction, and (2) general purpose industrial).