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Biodiesel has been used to reduce petroleum consumption and pollutant emissions. B20, a 20% blend of biodiesel with 80% petroleum diesel, has become the most common blend used in the United States. Little quantitative information is available on the impact of biodiesel on engine operating costs and durability. In this study, eight engines and fuel systems were removed from trucks that had operated on B20 or diesel, including four 1993 Ford cargo vans and four 1996 Mack tractors (two of each running on B20 and two on diesel). The engines and fuel system components were disassembled, inspected, and evaluated to compare wear characteristics after 4 years of operation and more than 600,000 miles accumulated on B20. The vehicle case history-including mileage accumulation, fuel use, and maintenance costs-was also documented. The results indicate that there was little difference that could be attributed to fuel in operational and maintenance costs between the B20- and diesel-fueled groups.

Planetary gears in heavy truck gearboxes are normally manufactured by forging a blank, turning, hobbing, shaving and heat-treatment followed by grinding. Due to the size of the gear the net shape capability of PM methods can be cost effective alternatively to conventional manufacturing. Warm compaction and surface densification are two PM methods to reach high density and thereby high strength and fatigue properties. Typical characteristics for PM gears manufactured by these methods are outlined.

A revolution in mobile hydraulic equipment is occurring. Conventional hydraulic spool valves with hydromechanical pressure compensators are being replaced by valve assemblies with four valve independent metering with electronically-controlled pressure compensation. In the system described here, two of the four independent valves are active during metering. This new topology offers significant advantages due to the two degrees of freedom provided. In this paper, the theory behind a new method of flow control based upon load feedback is presented for two of the five distinct metering modes. In addition, a new algorithm for setting the supply pressure is presented which is also based upon load feedback.

A rotary diesel fuel injection pump (RDFIP) takes drive from the engine assembly of an automobile engine. The critical part of RDFIP is plunger, which reciprocates as well as rotates in the plunger sleeve. The main function of plunger is to inject high pressure atomized fuel to the engine cylinder. Diesel fuel acts as a lubricant between the plunger and sleeve. The wear between the plunger and plunger sleeve causes considerable reduction in injection pressure and the quantity of fuel to the combustion chamber, which ultimately leads to an inefficiency of the engine assembly. The modeling and simulation of such a multi-domain dynamic system poses a formidable challenge. The conventional techniques are simple inadequate for the modeling and simulation of multi-domain dynamic systems. Bond Graph Method (BGM) is ideally suited for the modeling and simulation of multi-domain dynamic systems.

Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health studied alternatives to the use of diesel equipment in underground mines, as a means of reducing health hazards. Two of the alternatives being considered are battery-powered equipment and hydrogen-powered equipment. While battery-powered equipment is clean, recharging or replacing a battery takes longer and can be less convenient than refueling diesel equipment. In addition, the amount of electricity available from a battery is far less than the electricity available from a diesel hybrid configuration of comparable weight. Hydrogen-powered equipment faces similar challenges to those being faced by battery-powered equipment. However, if enough hydrogen can be put on-board the equipment quickly and conveniently via safe refueling options, then hydrogen-powered equipment can be competitive.

In severe - hot and humid - climates, Vehicles Air Conditioning Systems (AC systems) in use today suffers from a lack of performance and on a difficulty to efficiently meet the cooling load without causing a significant reduction in the performance of the internal combustion engine. This is especially true in applications where vehicles have long idling period and a lot of passengers, such as buses and passenger shuttles. An integrated cooling system has been implemented and tested in an Airport Passenger shuttle in order to improve fuel economy and cooling effectiveness in severe environment (up to 120 °F). The cooling system integrates a high-efficiency thermal storage technology (based on phase change materials) coupled to high performance compressors. Comprehensive performance analyses and testing of the high-performance system have highlighted many benefits of using the technology in such applications.

In this paper some design aspects related to external gear pumps balancing surfaces are studied, and some useful guidelines for designing bearing blocks balancing surfaces are suggested. In order to study bearing blocks axial balance, a numerical procedure for the determination of the pressure distribution inside the clearance bounded by gears sides and bearing blocks internal surfaces is firstly presented and applied. After, the influence of bearing blocks geometry and pump operating conditions on the widening thrust is highlighted, considering both constant and variable lateral clearance heights. Then, the computations are performed to evaluate the widening thrust variation as a function of bearing blocks relative tilt with respect to gears lateral sides, and both positive and negative bearing blocks tilts are evidenced and discussed.

The field of earth moving equipment is experiencing a transformation due to the introduction of more electronic control capability and advanced control concepts. Conventional hydraulic control systems are controlled by proportional directional spool valve. The construction of the spool valve is such that a given position of the spool determines the flow in and the flow out restriction sizes. Thus, metering in and metering out are dependent or coupled. A certain restriction size on the inlet corresponds to a certain restriction size on the outlet. Therefore, we have one degree of freedom. It can provide for good motion control but it cannot achieve energy saving potential at the same time. In this paper, the concept of ‘independent meter in / meter out’ will be emphasized. Decoupling of meter in from meter out provides for more controllability and potential for energy saving in overrunning load cases when compared with a conventional spool valve controlled hydraulic system.

Commercial Computational Fluid Dynamics (CFD) code ANSYS/Flotran has been used to simulate hydraulic oil flow inside valves. The fluid flow inside valve is treated as turbulent and adiabatic or iso-thermal. The CFD simulations presented in this paper have been carried out for the purpose of predicting hydraulic oil flow pressure drop inside hydraulic valves under certain operating conditions with the aim to minimize the pressure losses. The complete simulation procedure will be presented from parametric geometry creation with a 3-D solid CAD through final post-processing of results. Simulation results of different multiple-spool monoblock hydraulic valves are included. CFD simulation results are compared to experimental results. Some CFD model mesh sensitivity analysis result is also presented.

The design of a pressure compensated hydraulic valve is optimized using CFD analysis. The valve is used in a hydraulic system to control implement movement. High flow rates through the valve resulted in unacceptably high pressure drops, leading to an effort to optimize the valve design. Redesign of the valve had to be achieved under the constraint of minimal manufacturing cost. The flow path of hydraulic oil through the valve, the spool design, and various components of the valve that caused the high pressure drops were targeted in this analysis. A commercially available CFD package was used for the 3D analysis. The hydraulic oil flow was assumed to be turbulent, isothermal and incompressible. The steady-state results were validated by comparison with experimental data.

A nano-composite high strength (NCHS) steel was tested and evaluated in this work. Monotonic tension, strain controlled fatigue and fracture toughness tests were conducted at ambient temperature. Chemical composition, microstructure and fractography analysis were also performed. The NCHS steel showed excellent combination of high strength, high ductility and high fracture toughness with relatively low alloy content, compared with a S7 tool steel. Fatigue performance of the NCHS steel was also better than that of S7 tool steel. With the exceptional combination of high strength and high fracture toughness, the nano-composite high strength steel may have potential applications in gears, shafts, tools and dies where high fatigue performance, shock load resistance, wear and corrosion resistance is required.

The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow-rate (and of the correspondent discharging orifice design) on the cushioning characteristics variation is firstly introduced. Then, with respect to the case of the cylindrical cushioning engagement, both the reliability and the limits of the numerical approach are highlighted through a numerical vs. experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined and deeply analyzed.

Aerodynamic drag is the major component of Heavy Vehicle (HV) resistance at typical highway speeds, and thus strongly impacts related fuel economy because horsepower required to overcome this drag increases as the cube of vehicle speed. In an ongoing drag-reduction program for HVs conducted for the US Department of Energy (DOE), Georgia Tech Research Institute (GTRI) has been applying advanced new aerodynamic technology previously developed for aircraft. This technology uses tangential blowing to reduce the drag generated by these bluff-based high-drag vehicles, particularly the trailer. Drag reduction can be accomplished by this blown concept without moving surfaces, and it also offers the potential to increase drag for braking if needed and to overcome both increasing drag and destabilizing side forces due to large side winds and gusts.

The modern diesel engine is used around the world to power applications as diverse as passenger cars, heavy-duty trucks, electrical power generators, ships, locomotives, agricultural and industrial equipment. The success of the diesel engine results from its unique combination of fuel economy, durability, reliability and affordability - which drive the lowest total cost of ownership. The diesel engine has been developed to meet the most demanding on-highway emission standards, through the introduction of advanced technologies such as: electronic controls, high pressure fuel injection, and cooled exhaust gas recirculation. The standards to be introduced in the U.S. in 2007 will see the introduction of the Clean Diesel which will achieve near-zero NOx and particulate emissions, while retaining the customer values outlined above.

This paper describes the results of experiments that were performed using a Ground Research Vehicle (GRV) at the National Aeronautics and Space Administration's (NASA) Dryden Flight Research Center in Edwards, CA and a comparison with computational results. The GRV is a modified 1984 General Motors (GMC) van and measures 40 feet long and 9 feet high, with a base area of 83 by 83, and it weighs 10260 lbs and holds a crew of up to three. Air data is measured from a nose-boom, 2 global positioning (GPS) units, and an absolute Honeywell Pressure Transducer with 4 Electronic Signal Processor (ESP) scanners and 64 surface pressure ports. This allows for detailed measurements of the surface pressure profiles around the vehicle. The total vehicle drag is estimated from coast-down tests, while the pressure component of the drag force may be calculated by integrating the pressure profiles on the front and base of the vehicle.

Computational simulations of the Modified Ground Transportation System1 (M-GTS), a 1/14th-scale simplified tractor-trailer geometry, are performed at both laboratory and full-scale Reynolds numbers using the NASA overset grid code OVERFLOW2. Steady Reynolds' Averaged Navier-Stokes (RANS) simulations are conducted to deepen the understanding of tractor-trailer gap flow structure, and to ascertain the time-averaged efficacy of tractor cab extenders and trailer-face splitter plates in reducing aerodynamic drag in typical crosswinds. Results of lab-scale simulations compare favorably to body force and particle image velocimetry (PIV) data obtained from University of Southern California (USC) experiments for two tractor-trailer gap lengths. Full-scale simulations highlight model geometry limitations and allude to the use of splitter plates in place of, or in conjunction with, tractor cab extenders.

All suspension systems have a common goal, which is to improve the ride in terms of comfort, handling, and safety. This is accomplished by influencing the motions afflicted by road irregularities to the wheels and axles while minimizing their affect on the vehicle body and frame. A successful design would therefore incorporate (1) a high Sprung-To-Unsprung-Mass-Ratio, (2) a Mass-Spring-Damper System between the vehicle body and the wheels, and (3) an anti-roll bar. Consequently, the wheels and axles endure the most of the motions caused by road irregularities while their affect is minimized on the vehicle body as desired. The objective of the Anti-Roll Stability Suspension Technology (ARSST) is to become an industry standard active suspension system for all vehicles while simultaneously offering cost-effective and performance-enhancing control to improve vehicle handling, safety, and comfort.

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.

Direct vehicle performance comparisons were made between a full 6s/6m and a simpler 4s/4m system, as applied to a 6x4 Class 8 straight truck having a walking-beam rear suspension design. The 4s/4m system was run in both intermediate-axle control and trailing axle-control configurations. The systems were compared with modern air-disc brakes on the vehicle The systems were compared at LLVW (unladen) and GVWR (fully loaded) for high speed stopping performance and stability on a high-μ surface and a wetted split-μ surface, as well as Brake-in-Curve stability on a wetted low-μ 500-ft radius turn. In this paper, stopping distances are statistically compared to quantify effects of the various ABS control strategies on dry and wet stopping efficiency. In addition, newer techniques of using wheel-slip histograms generated from in-stop data are used to compare more detailed system behavior and predict their effects on vehicle stability under braking.

The California Air Resources Board (CARB) has tested the utility of the Model 3090 Engine Exhaust Particle Sizer (EEPS™) by TSI in measuring pre- and post-trap particulate matter (PM) emissions from a medium-duty truck. Pre- and post-trap measurements are used to evaluate the effect of engine operation on PM emissions and trap effectiveness. Because of mounting evidence that ultrafine (UF) particles are harmful, regulatory agencies are investigating new and promising instrumentation for improved characterization of such particles in emissions. This is especially true for fast-response instruments that can be used to size-resolve real-time UF emissions from prominent sources such as diesel engines. The EEPS uses diffusion charging, electrical mobility segregation, and electrometers. It is designed for the number measurement of transient aerosols in the size range of 5.6 to 560 nm. It collects 10 measurements per second at a flow rate of 10 lpm.