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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.

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.

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.

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.

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.

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.

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.

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 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.

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.