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The importance of minimizing air entrainment and enhancing air release in hydraulic fluids has been recognized for over 40 years. These properties are dependent on the composition of hydraulic fluids, especially on the presence of contaminants which inhibit air release and additives which promote it. One objective of this paper is to present an overview of this critically important technology as it has unfolded over the last 40 years. The second objective of this paper is to integrate into this summary recent research results on the impact of additives on air release properties.

COMMERCIAL VEHICLES ARE INVOLVED IN A HIGHER PERCENTAGE OF FATAL COLLISIONS THAN OTHER TYPES OF VEHICLES, EVEN THOUGH THEY ARE INVOLVED IN A RELATIVELY SMALL PERCENTAGE OF ALL MOTOR VEHICLE COLLISIONS. TRUCK ROLLOVER COLLISIONS AT ROADWAY CURVES ARE ONE TYPE OF COLLISION THAT HAS SERIOUS CONSEQUENCES, AND CERTAIN LOCATIONS ARE PARTICULARLY PRONE TO ROLLOVER COLLISIONS. THE SUBSTANTIAL DIRECT DAMAGE COSTS USUALLY ASSOCIATED WITH TRUCK ROLLOVERS INCLUDE HUMAN INJURYAND DEATH, INSURANCE, AND ECONOMIC LOSSES. AN AUTOMATIC TRUCK ROLLOVER WARNING SYSTEM (ATRWS) IS AN INTELLIGENT TRANSPORTATION SYSTEM THAT HAS THE POTENTIAL TO SAVE LIVES, REDUCE INJURIES AND DECREASE COSTLY DAMAGE BY PREVENTING ROLLOVER COLLISIONS. HAMILTON ASSOCIATES HAS RECENTLY CONDUCTED A STUDY FOR THE INSURANCE CORPORATION OF BRITISH COLUMBIA TO EVALUATE SUITABLE SITES FOR THE INSTALLATION OF AN ATRWS.

Plastic media blasting (PMB) has been approved for paint removal on Naval aircraft on metallic structures with thicknesses of 0.016 inch and greater and monolithic carbon/epoxy laminates with thicknesses of 0.073 inch and greater. This report documents the test effort to qualify PMB as a paint removal process for thin laminate carbon/epoxy honeycomb sandwich structures. Type V, acrylic media was used for blasting. Test panels were subjected to 10 and 20 repetitive blast cycles. Panels were not painted in between blast cycles representing a worst-case blast condition. Optical microscopy was performed on panels subjected to both 10 and 20 cycles. Mechanical property testing (long beam flexure and flatwise tension) was performed on control specimens and specimens subjected to both 10 and 20 blast cycles.

The allowable noise emission of vehicles has been continuously reduced by legislation in the past. In parallel the interior noise level and noise quality have been improved dramatically. Even small size cars show today remarkable sound quality. This general effort to reduce vehicle noise has brought about a reduction in the combined effects of noise and vibration on the passengers. Today's vehicles exhibit more closely matched noise contributions from the engine, transmission, inlet and exhaust systems as well as road inputs via the suspension. For a further improvement of vehicle noise levels and sound quality, simple reduction of individual noise sources is no longer a suitable approach. A full understanding of their combined effect on vehicle noise is required, for cost-effective and production-feasible solutions to lead to the desired noise reduction or the achievement of a typical “Brand Sound” through sound engineering.

After 300 kph the aerodynamics noise emitted by the French High Speed Train T.G.V. (Train Grande Vitesse) becomes preponderant. The pantograph and roof environment located in the top of the rear power car are one of the sources which participate in the overall noise of the train. Investigations in an anechoi'c wind tunnel are performed firstly with a real pantograph, secondly with a fine 117 scale power car model. After a trainborne Velocimetry Laser Doppler campaign, the real turbulent boundary layer is simulated in the wind tunnel. The decreasing of the radiated noise level is obtained by modifying the geometry of both the pantograph and the roof and by adding devices on the pantograph itself. These results suggest that close attention needs to be paid to the roof geometry.

High-fidelity overall vehicle simulations require efficient computational routines for the various vehicle subsystems. Typically, these simulations blend theoretical dynamic system models with empirical results to produce computer models which execute efficiently. Provided that the internal combustion engine is a dominant source of vehicle vibration, knowledge of its dynamic characteristics throughout its operating envelope is essential to effectively predict vehicle response. The present experimental study was undertaken to determine the rigid body modal content of engine block vibration of a modern, heavy-duty Diesel engine. Experiments were conducted on an in-line six-cylinder Diesel engine (nominally rated at 470 BHP) which is used in both commercial Class-VIII trucks, and on/off-road military applications. The engine was mounted on multi-axis force transducers in a dynamometer test cell in the standard three-point configuration.

The customer's perception of diesel sounds is receiving more attention since diesel engines are being used more frequently in recent years. This paper summarizes the results of a study investigating the sound quality of diesel idle sounds in eight vans and light trucks. Subjective evaluations were conducted both in the US and the UK so that a comparison could be made. Paired comparison of annoyance and semantic differential subjective evaluation techniques were used. Correlation analysis was applied to the subjective evaluation results to determine annoying characteristics. Subjective results indicated that most annoyance rankings were similar for both the US and UK participants, with some specific differences. Correlation of objective measures to annoyance indicated a high correlation to ISO 532B loudness, dBA and kurtosis in the 1.4 kHz to 4 kHz range (aimed at quantifying the impulsiveness perception).

The data measured during an ISO 362 pass-by-noise test are strongly non-stationary due to the fast acceleration of the vehicle and its moving position with respect to the ISO microphone position. Nevertheless, one would like to obtain an understanding of the relative contribution of the various noise generating components during the test. Since the classical signal analysis procedures based on the FFT calculation and auto/crosspower averaging for coherence/correlation analysis are no longer applicable, as they implicitly assume signal (and process) stationarity, an approach based on Autoregressive Vector (ARV) modelling of a set of measurement signals was developed and applied. An ARV model is calculated directly from a set of time data of limited duration.

In January 1996 Mercedes-Benz has introduced a new 4-cylinder engine OM 904 LA of the new engine family for light commercial vehicles. The power range of the OM 904 LA comprises ratings from 90 kW up to 125 kW at 2300 rpm. From the beginning of the design of this engine, a noise emission output as low as possible was strived for, aside from the high targets as far as durability, maintenace and fuel consumption are concerned. The basis is the development of noise regulations for commercial vehicles. The noise reduction measures have to be concentrated on the engine since up to now it still is one of the main noise emission sources at the vehicle. Already at the lay-out of the engine the prerequisits for a low-noise engine behaviour have been taken into consideration. The engine is equipped with a fuel injection system featuring particular unit injector pumps for each cylinder which is superior to the conventional in-line injection pump as far as acoustics are concerned.

Cooling fan performance: pressure rise, flow rate, shaft power have been acquired. The control variables for these measurements include the fan rprn and the relative immersion of the fan into the shroud. In addition tuft visualizations and hot-wire anemometry have been used to visualize and measure the velocity field in the wake of the fan. The velocity measurements have been processed to provide phase averaged mean and RMS fluctuation levels. The mean values have been differentiated to provide the phase averaged streamwise vorticity magnitudes. The data are used to gain an understanding of the fluid mechanical attributes of the flow field, as well as to provide experimental results for comparison with computational investigations.

Heavy truck development is characterized by increasing engine performance, torque and payload, which increases the demand of using hydrodynamic retarder for braking. At the same time there is a demand of reducing exhaust gas emissions and noise and increasing comfort and driving safety. As a consequence manufacturers of heavy duty trucks are demanding higher performance from their cooling systems with less available space in the vehicle. To meet these needs, a novel high performance compact cooling system was developed. This system differs from conventional systems in that it utilizes a radial arrangement of the cooling components that allows up to 1.4 times more heat transfer surface to be installed in the same space with all air side surfaces working at ambient temperature.

A mathematical simulation model was developed to calculate the cooling loads in a cab. The cooling loads calculations are described: Solar irradiation through glasses, conduction through the body walls and glasses, conduction through motor compartment, fresh air intake/infiltrations, people and equipments. Fields experiments were conducted to evaluate the conduction through walls and glasses and the total cooling load models. Precision less than 5% was gotten between experimental measurements and model results. In the summer situation, studies about the effects of the cab orientation, the time, the external paint and the tint of the glasses in changing the conduction and solar radiation cooling loads, were conducted. Cab orientation and the time can change this cooling loads by 225%. Variation by 30% was gotten from different paints and glasses.

A theoretical model is developed for crushing of honeycomb structures. Axial crushing is considered for both adhesive bonded and welded honeycombs. The two mentioned cases present different kinematics of collapse; consequently, the Mean Crushing Strength assumes different values. The theoretical model discussed is also able to predict Bar Compressive Strength which is a fundamental variable to be taken into account in the design of energy absorbers for the automotive industry. The analytical results are successfully compared with experimental literature data and numerical results.

This paper reports on a continuing Ohio Department of Transportation (ODOT) two year evaluation of a biodiesel blend, B20, (an 80/20 blend of diesel fuel and methyl soyate) in fleet operations. The evaluation is being conducted in two adjacent counties in northwest Ohio. The Fulton county ODOT garage has been operating all diesel powered equipment on B20 since March of 1996 and has been comparing operating results with counterpart equipment in nearby Williams county which has continued operations on diesel fuel. The results of this test are being monitored by Battelle which is collecting and analyzing detailed operational and reliability data on five (5) Navistar-International dump truck / snow plows in each county. Chassis dynamometer evaluation of engine power changes, “before/after” snap-idle smoke tests, identification of cold weather issues, and the consistency of on-site fuel blending have been conducted and are discussed in this paper.

Under hot transient conditions, the effects of gasoline properties, such as the research octane number (RON), the motor octane number (MON) and types of components on acceleration performance were investigated using four ‘Premium Gasoline Required Vehicles’ which are Japanese commercial vehicles equipped with knock sensors (KSs) and an electronic control unit (ECU) to prevent the engines from knocking. Regarding the fuel, two series of fuels were used. One of them {Primary Reference Fuel Series (PRF series)} was prepared to investigate the effectiveness of the octane number of PRF (ON). The other {Components Series (COMP series)} was prepared to investigate the effects of fuel components on the same. Fuels in the COMP series had almost the same RON level, which was almost equal to 90. In the PRF series, the acceleration performance of all vehicles were improved as ON increased.

The Maryland Mass Transit Administration conducted an LNG transit bus demonstration in Baltimore, Maryland. A refueling facility was constructed and maintenance facilities were modified to provide support for the demonstration. During the demonstration operational data were collected on the buses and facilities. Problems encountered with the vehicle LNG fuel systems are reviewed and discussed. This paper summarizes the findings and operation of the LNG fleet during the demonstration and projects future LNG vehicle and operational costs.

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.