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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.

The control over particulate emissions is becoming increasingly important in modern diesel engines for Heavy Duty applications, that will comply to more and more stringent emissions norms. Use of particulate traps is an effective means of achieving this with the need to regenerate the particulate trap being imperative. Passive regeneration using NO2 by conversion of NO, as well as regeneration at lower temperatures with catalyzed DPF and the influence of NOx to soot ratio on this, is the subject of the paper. Both coated and uncoated filters in fresh and aged state are evaluated at temperatures typical of passive NO2 and Oxygen-based soot regenerations and the results discussed.

This paper covers the test work done on the comparative characterization of particulates using different blends of biofuels (like biodiesel and ethanol in diesel fuel) in light commercial vehicle under different operating conditions. The test vehicle selected was equipped with Direct Injection (DI) diesel engine with inline fuel injection pump. Under transient operating condition (Indian Driving Cycle), the results indicate that with increased percentage of biodiesel (upto 20%) in the blend, particulate concentration decreases. However, with 5% ethanol diesel blend, particulate concentration increases when compared with neat diesel as well as biodiesel blends while mass concentrations are lower with both the biofuels as compared to neat diesel. It is observed that the nanoparticles are higher with 5% ethanol diesel in IDC test mode.

For protecting human health and preserving the clean environment, current regulations stipulate acceptable levels of particulate emissions based on the mass collected on filters obtained by sampling in diluted exhaust. Such regulations will be imposed not only on-road engines but also off-road engines. From the point of view of human health [1], so-called nano-particle (d<50nm) is thought to be nuisance because it could reach deeper lung tissue. So, many researches have been done in this research field [2]. A series of experiments were conducted on an off-road general purpose direct Injection (DI) diesel engine using EEPS (Engine Exhaust Particle Sizer) to make real time particle size distribution measurements possible. The data presented covers whole operating conditions including the operating modes of off-road diesel engine emission test (C1mode). Additionally, PM emissions in transient (NRTC test cycle) engine operation were examined.

One of the possible solutions in order to reduce NOX and PM emissions and fuel specific consumption in a diesel engine is to substitute a part of the diesel oil with a gaseous fuel. Natural gas, due to the high octane number, allows such substitution without great modifications to the original engine, just introducing the gas feeding system. The utilization of natural gas (usually referred as “alternative fuel”) instead of oil is an important advantage of such technology in terms of energy sources. In this paper the conversion of the IVECO 8360.46R engine, for bus applications, to dual-fuel operations is discussed. Experimental tests were performed to define the general behaviour of the engine, especially at partial loads. Main target of the present study was the analysis of engine requirements to maintain the same output load as the full-diesel operation, and controlling exhaust emissions.

The aim of the current study was to construct a model of a road rail vehicle in JACK and investigate the view of the articulating arm of the machine for human models of different stature in test conditions simulating a digging task and a lifting task. The JACK software was also used to determine the likely effects on operator comfort of postural adjustments which would be required to see different parts of the articulating arm. Modelling of the tasks using JACK has been a useful first step in identifying the limitations in the field of view for vehicle operators of different statures. The use of the view cones in JACK have been evaluated and the simulations have highlighted the potential for discomfort arising from postural adjustments which would be necessary in the tasks. Further research on operators' postures and visual strategies during real world digging and lifting tasks is now necessary.

The Tapered Element Oscillating Microbalance (TEOM) measures captured particle mass continuously on a small filter held on an oscillating element. In addition to traditional filter-based particulate matter (PM) measurement, a TEOM was used to characterize PM from the dilute exhaust of trucks examined in two phases (Phase 1.5 and Phase 2) of the Coordinating Research Council (CRC) Heavy-Duty Vehicle Emissions Inventory Project E-55/E-59. Test schedules employed were the Heavy Heavy-Duty Diesel Truck (HHDDT) test schedule that consists of four modes (Idle, Creep, Transient and Cruise), the HHDDT Short (HHDDT_S) which represents high-speed freeway operation, and the Heavy-Duty Urban Dynamometer Driving Schedule (UDDS). TEOM results were on average 6% lower than those from traditional particulate filter weighing. Data (in units of g/cycle) were examined by plotting cycle-averaged TEOM mass against filter mass. Regression (R2) values for these plots were from 0.88 to 0.99.

Intercity tractor-trailers and other vehicles with diesel engines idle a significant portion of the time. Idling also produces airborne emissions and noise; a number of cities and states have banned or restricted idling to reduce pollution and noise. Reducing idling truck idling is thus an important environmental issue. In the freight transportation industry, a large part of the idling time is due to off-road heating and air conditioning. The heating ventilating and air conditioning systems (HVAC systems) in use today on internal combustion vehicles do not lend themselves to efficient application in vehicles having long idling period, especially in the trucks market. An integrated climate control system has been developed over the past seven years. Applying a high-efficiency thermal storage technology (based on phase change of specific materials), the Climate Control System has been implemented in long haul trucks to reduce idling (for “off road and off engine” heating and cooling).

A Stewart & Stevenson M1084A1 FMTV 5-ton cargo truck was used as the subject of a study to evaluate advanced powertrain thermal management components and subsystems. Funded by the U.S. Army TACOM and the National Automotive Center (NAC) under a Small Business Innovative Research grant (SBIR Phase II), the project focused on improving thermal management of the vehicle while reducing the peak fuel consumption by >10% in a vehicle having limited ram air cooling. The FMTV was used as a surrogate test bed to investigate thermal management technologies that could be applied to vehicles with confined package space, such as light armored vehicles. The vehicle was equipped with a thermal management system featuring distributed system architecture, electric coolant pumps and fans, electronic control valve, multiple air-cooled heat exchangers, and an electronic control system with PID feedback. The entire thermal management system was mounted in a metal enclosure behind the truck cab.