Search Results

Ford Motor Company has introduced its dedicated Natural Gas Vehicle (NGV) trucks as mid-year 1997 offerings to complement its dedicated Crown Victoria and bi-fuel Qualified Vehicle Modifier (QVM) product line-up. The 5.4L F-250 full-size pick-up truck and the 5.4L E-250/E-350 full-size vans are production vehicles maintaining Original Equipment Manufacturer (OEM) quality and warranty while complying with all applicable corporate, federal and state requirements. Both trucks are the first OEM vehicles to certify at the Super Ultra Low Emission Vehicle (SULEV) California medium-duty vehicle standard, the Federal Ultra Low Emission Vehicle (ULEV) standard, and the Federal Inherently Low Emission Vehicle (ILEV) emission standard. The use of natural gas (NG) as a vehicle fuel required unique hardware changes in the areas of fuel storage, fuel metering, and the emission control system.

The plasticity characteristics of the material were used to model the cutting force material, and were verified by using FEM techniques. In addition, the solutions generated by The Merchant's Circle were proven by vector algebra, and a shear angle solution which uses the plasticity characteristics of the material is also presented. A good agreement was found between the mathematical models, FEM results, and experimental data results found in open literature.

During the last decade, several technological advances have taken place in the construction and fabrication industry in terms of methods, processes and tools which ultimately reduce fabrication time and costs. Fastening of metal plates with bolts and nutes in civil construction of large structures has recently been replaced by self drilling-tapping fasteners. The technique of using a self drilling-tapping fastener not only eliminates use of separate drills and drilling processes, but also eliminates the use of bolts and nuts. In addition, the time to join two plates by a self drilling-tapping fastener is significantly shorter than the time required for joining plates by conventional bolting methods. Although self drilling-tapping fasteners have many advantages, it is equally important that they demonstrate consistent performance in field applications.

Welding residual stress is one of the primary factors responsible for cracking at the access hole interface between the flange and web plate of welded heavy W-shapes. During multi-pass welding, cracks can be found in either the flange plate or the web plate, depending upon welding sequence, joint details and access hole size. In this study, an integrated numerical and experimental investigation was conducted to evaluate the effects of welding parameters and joint geometry on the magnitude and distribution of residual stresses in thick-section butt joints. The results provide guidelines for improved design for welding of heavy W-shapes.

This paper identifies potential performance benefits and computational costs of applying advanced multivariable control theory concepts to coordinate the control of a general multi-degree-of-freedom fuel system. The control variables are injection duration and pressure. The focus is on the design of a robust multi-input multi-output controller using H-infinity and mu synthesis methodology to coordinate the control of injection duration and pressure; reduce overshoots and system sensitivity to parameter variations caused by component aging. Model reduction techniques are used to reduce the order of the H-infinity controller to make it practically implementable. Computer simulation is used to test the robust performance of a generic engine and fuel system model controlled by the reduced order H-infinity controller and a traditional proportional plus integral controller.

This research project investigates the feasibility of using a commercial finite element code to capture the dynamic response of a typical rubber-belted tractor for agricultural applications. The investigation focused on one of Caterpillar Inc.'s Ag Challenger Series tractors. A feasibility study concluded that Abaqus/Explicit [1], a finite element code utilizing the explicit scheme, had the desirable features needed to develop such a large-scale tractor model. These features include an efficient time integration scheme, three-dimensional generalized multiple contacts, and nonlinear material characterization. The fully-assembled tractor model was successful in simulating the forward motion. A preliminary validation indicated that the tractor model was able to predict a trend which was observed in field tests accurately.

The differences between courses offered agricultural and mechanical engineers are examined. The topics in the courses are reviewed in some detail. The students start with a review of basic fluid mechanics followed by an introduction to bulk modulus. Governing equations for pumps motors and valves are introduced next. Course emphasis then diverges. The agricultural engineers cover the basics of control theory to cover a deficiency in their undergraduate curriculum. The mechanical engineers embark on more rigorous examination of the simulation of fluid power components. Students in both departments may elect to take a 1 cr. laboratory course. The laboratory exercises are discussed.

The success of agricultural and construction machinery owes a great deal to the effective use of fluid power. Most fluid power systems are configured with a positive displacement fluid pump that is large enough to meet the flow requirements of many work circuits. Different work functions require a variety of fluid flow and pressure values to provide the desired operation. System branches, therefore, must include specialized flow and pressure regulating valves. The development of a mathematical model of a fluid flow control valve follows.

Multidimensional numerical simulations are performed to predict and optimize engine performance of a spark-ignited natural gas engine. The effects of swirl and combustion chamber geometry on in-cylinder turbulence intensity, burning rate and heat transfer are investigated using the KIVA multidimensional engine simulation computer code. The original combustion model in the KIVA code has been replaced by a model which was recently developed to predict natural gas turbulent combustion under engine-like conditions. Measurements from a constant volume combustion chamber and engine test data have been used to calibrate the combustion model. With the numerical results from KIVA code engine thermal efficiencies were predicted by the thermodynamics based WAVE code. The numerical results suggest alternative combustion chamber designs and an optimum swirl range for increasing engine thermal efficiency.

Diesel engines are irreplaceable in tunnel construction. The particulate emissions of present day engines are so high that the imission limits valid since 1991 cannot be attained by ventilation alone. This problem had to be solved preparatory to the large tunnel projects in Switzerland, Austria and Germany. Several retro-fitting measures were investigated both in the laboratory and in field tests, within the scope of the Project VERT. Oxidation catalytic converters, exhaust gas recirculation, and the usage of special fuels cannot be recommended. Particulate trap deployment, in different systems, was mostly successful. Particular attention was focused on the dependable filtration of finest particulates < 200 nm. The VERT proved that exhaust gas after-treatment with particulate traps is feasible, cost effective and controllable in the field. Pertinent directives are in discussion.

The body or chassis of the modern motor vehicle is still fundamentally and commonly designed on the horse and cart concept. This solid chassis, upon which the cart was built, offers little or no crushing zone effect in the event the motor vehicle and its occupants are subject to an impact due to a collision. Although we see an array of modern motor vehicle safety devices, injury and fatalities are still appearing at an alarming rate, some directly due to these safety devices. This paper attempts to present a synergistic approach to motor vehicle safety. One of the most important safety features that has been overlooked by most automobile manufacturers is a uniform crushing zone on bumper areas. It appears at present and possibly in the future that crushing zones on bumper areas have been and will be neglected. Thus a fundamental safety principle that could be used to prevent injury and fatalities in automobile accidents will be neglected.

The trajectory solution procedures of the original CRASH program included both the SPIN routine and an exploratory trajectory simulation option to approximate and refine the linear and angular velocities at separation. The resulting separation speeds were then used to determine the impact speeds by means of application of the principle of conservation of linear momentum. This paper presents a detailed review of the logic, rationale and limitations of the trajectory solution procedures of the original CRASH program and discusses a number of refinements including: incorporation of the principle of conservation of angular momentum, approximations of the effects of changes during collision in the positions and orientations of the two vehicles and of the effects of external forces and moments that act on the two-body system during the collision, and adaptations of optimization techniques for error reduction and convergence in iterative solutions.

This updated paper presents chassis dynamometer emissions testing of various heavy duty vehicles with and without retrofitted diesel oxidation catalyst technology. Analysis is provided into both the vehicle emissions baselines and emissions with retrofitted catalyst technology over the New York Composite and Central Business District cycles. The vehicles studied include four urban buses, two school buses and four heavy duty trucks. Some of these vehicles in this study have been followed for up to two years. The paper will discuss in-use heavy duty vehicle emissions issues and the use of diesel oxidation catalyst technologies.

In this paper, the system identification theory and method using dynamic neural networks are presented, the multilayer feedforward networks employed, the backpropagation with adaptive learning rate algorithms proposed. Finally the comparision of network output with that of the hydrostatic drive system of secondary regulation is given, and output error, sum-squared error et al, or the results that embody the effect of system identification given sine input to it are provided.

The usage of personal computers by members of The Maintenance Council of the American Trucking Associations has been measured through primary market research. Survey results indicate that maintenance management utilization of personal computers is significant and can be expected to continue to grow over the next several years. The computer platform is relatively new and includes peripherals such as communications modems and CD-ROM. Applications most prevalent today are office management and personal productivity packages. Future demand is for more vertical software specific to maintenance training, diagnostics and management.

As modern vehicular applications demand higher power density gears, accurate analytical tools to predict gear stress are required. The finite element method has been successfully applied to the analysis and design of components and structures of a vehicle. However, it is still difficult to apply to gears due to very complicated geometry, especially in the root fillet area. Since a good knowledge of the gear root geometry is required to calculate bending stress, the purpose of this paper is to present the root fillet geometry of spur, helical, spiral bevel, and hypoid gears. The gear root fillet equations are derived based on the simulation of cutting tool motion on the gear blank during the manufacturing process. For spur and helical gears, the root fillet geometry cut by a rack with and without cutter tip radius is discussed. The phenomenon of undercut is discussed as well.

In July of 1997, GM will introduce a Police Pursuit Sport Utility to the law enforcement market. The vehicle is based on the popular Chevrolet Tahoe full- size, four-door utility truck that was introduced in 1996. It is shorter than the Suburban and available in only a two-wheel drive version for the Police Pursuit Vehicle (P.P.V.) program. This vehicle replaced the now canceled Chevrolet Caprice, which traditionally had been developed to be a P.P.V. It created a new market niche with its unique size and features. The combination of using proven, existing components and following an aggressive testing schedule allowed GM to develop this unique new product in a 48-week time frame, a relatively short development time for such a challenging program. The GM Truck Group used proven technology on this program.

Operational Deflection Shapes (ODS) analysis has been in existence for more than 20 years, but has been overshadowed by its progenitor, Modal analysis. This paper describes how and why ODS analysis was applied to the development of the GMTG T-series Medium Duty Truck and presents some examples of the results obtained.

Rear end break-away, or skate, is a phenomenon that occurs when live axle equipped vehicles are driven aggressively on rough, winding roads. This paper reviews instrumented dynamic testing of a specially built vehicle. Initial testing linked skate to the tramp oscillation mode of the rear axle. Two variables were evaluated for reducing skate: shock absorber valving and shock absorber placement. The principal conclusion of this work is that although some reductions in skate are possible by adjusting shock absorber valving, optimum control of skate is facilitated by packaging the shock absorbers near the wheels.

SAE research into the ISO 14000 series of standards offers insights into the opinions and attitudes of the experts, U.S. industry leaders and government representatives. A series of focus groups with industry leaders, in-depth interviews and a review of secondary research data, provide a perspective on the ISO 14000 series as it is understood on the eve of acceptance by the international community. This research study, sponsored by SAE, explores reactions to both the early components of the standard (14001 and environmental management systems scheduled to be adopted in the summer of 1996) and those portions of the standard still being developed which relate more specifically to product components and the global standardization of life cycle analysis and eco-labeling.