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The U.S. Department of Energy, through Argonne National Laboratory, and in cooperation with Natural Resources-Canada and Chrysler Canada, sponsored and organized the 1996 Propane Vehicle Challenge (PVC). For this competition, 13 university teams from North America each received a stock Chrysler minivan to be converted to dedicated propane operation while maintaining maximum production feasibility. The converted vehicles were tested for performance (driveability, cold- and hot-start, acceleration, range, and fuel economy) and exhaust emissions. Of the 13 entries for the 1996 PVC, 10 completed all of the events scheduled, including the emissions test. The schools used a variety of fuel-management, fuel-phase and engine-control strategies, but their strategies can be summarized as three main types: liquid fuel-injection, gaseous fuel-injection, and gaseous carburetor. The converted vehicles performed similarly to the gasoline minivan.

The effectiveness of using catalytic aftertreatment to control excessive hydrocarbon and carbon monoxide emissions is well known. However, a thorough understanding of how the catalyst and vehicle work together as an integrated system is still in developmental stages. A major goal of the investigation was to examine catalyst performance under the dynamic conditions existing during normal vehicle operation. The impact of applying catalytic aftertreatment, with and without the addition of secondary air, to three small 2-stroke motorcycles is examined. It is found that catalysts respond well to the varied conditions encountered with 2-stroke engine powered vehicles. While the addition of secondary air is beneficial to increased hydrocarbon reductions, its impact on carbon monoxide can be variable and a function of vehicle operation.

A combined one-dimensional, multi-dimensional computational fluid dynamic modelling technique has been developed for analysis of unsteady gas dynamic flow through automotive mufflers. The technique facilitates assessment of complex designs in terms of back-pressure and noise attenuation. The methodology has been validated on a number of common exhaust muffler arrangements over a wide range of test conditions. Comparison between measured and simulated data has been conducted on a Single-Pulse (SP) rig for detailed unsteady gas dynamic analysis and a Rotary-Valve (RV) rig in conjunction with an anechoic chamber for noise attenuation analysis. Results obtained on both experimental arrangements exhibit excellent gas dynamic and acoustic correlation. The technique should allow optimisation of a wide variety of potential muffler designs prior to prototype manufacture.

Vibrations induced by the internal flow in a typical seat valve used in mobile hydraulics are investigated under various extreme flow conditions. To reduce the noise associated with these vibrations, it is necessary to gain a thorough understanding of the flow in this particular hydraulic component and of the dynamic characteristic of the hydraulic system. The three-dimensional and turbulent flow in the valve is studied and characterized applying Computational Fluid Dynamics (CFD). Subsequently, dynamic phenomena, such as pressure pulsation, flow rate fluctuation, and body fixed acceleration, are analyzed from measurements on a hydraulic test assembly. The combined method using CFD and direct measurements suggests itself as a very suitable approach to gain more understanding not only of the flow processes in the valve but also of the causes for the instability of the valve closing body.

This paper presents an overview of the LucasVarity Vehicle Simulation Laboratory and its capabilities and benefits to the company's development of brake and brake control systems for the automotive industry. LucasVarity has been using simulation in its product development process since 1991. Two types of simulation are currently used: open loop and closed loop. The Open Loop Simulator (OLS) is a sensor signal design tool and real-time transmitter used primarily to test brake control system algorithms. Closed loop simulation (CLS) includes two levels: non-real-time desktop simulation (CLSDT) or real-time with hardware in the loop simulation (CLSH). Both levels use a vehicle model, designed by LucasVarity engineers, which is currently solved for eighteen degrees of freedom representing three-dimensional vehicle dynamics. Hardware in the loop simulation is performed on the CLSH and may include a brake fixture mounted in a laboratory hydraulic chamber or an entire vehicle.

Recent changes in state I/M (Inspection/Maintenance) programs have significantly changed diagnosis and repair procedures. For many states, electronic engine controls require some form of loaded-mode I/M test. The static tests developed in the 1970s for carburetors and points/condenser ignition do not satisfactorily differentiate between modern clean and dirty cars. What do these changes mean to I/M technicians, specifically in High Enhanced areas? How do we define a “qualified” I/M technician? Many states are taking different approaches to I/M technician training, and individual states are redefining a “qualified service technician”. Such programs with overlaps have serious implications for technician training, OEM and aftermarket, with probable state/state variations Inevitable future changes in engine-management technology, state I/M programs, and vehicle fuels require a flexible dynamic approach to training and certification of technicians.

The objective of this work was to establish whether two detergent-type additives(A and B) influence the drop size and evaporation of two Diesel fuels (1 and 2) under Diesel engine conditions. Two experiments were performed: visualization of liquid and vapor fuel by the exciplex technique in a motored single-cylinder engine and measurement of the Sauter mean diameter, total drop cross sectional area and total drop volume by laser diffraction in a spray chamber. The same Diesel injector and pump system were used in the two experiments. The engine tests were carried out using a high aromatic content fuel (1) particularly suited for the exciplex studies. These studies showed that additive A yielded a lower vapor signal than additive B, which in turn gave a lower vapor signal than untreated fuel. Spray chamber results were obtained for both fuel 1 and 2. Additive A reduced the evaporation of fuel 1 whereas additive B gave a smaller and less consistent affect.

A better understanding of turbulent kinetic energy is important for improvement of fuel-air mixing, which can lead to lower emissions and reduced fuel consumption. An in-cylinder flow study was conducted using 1548 Laser Doppler Velocimetry (LDV) measurements inside one cylinder of a 3.5L four-valve engine. The measurement method, which simultaneously collects three-dimensional velocity data through a quartz cylinder, allowed a volumetric evaluation of turbulent kinetic energy (TKE) inside an automotive engine. The results were animated on a UNIX workstation, using a 3D wireframe model. The data visualization software allowed the computation of TKE isosurfaces, and identified regions of higher turbulence within the cylinder. The mean velocity fields created complex flow patterns with symmetries about the center plane between the two intake valves. High levels of TKE were found in regions of high shear flow, attributed to the collisions of intake flows.

The flow field contained within ten planes inside a cylinder of a 3.5 liter, 24-valve, V-6 engine was mapped using a three-dimensional Laser Doppler Velocimetry (3-D LDV) system. A total of 1,548 LDV measurement locations were used to construct the time history of the in-cylinder flow fields during the intake and compression strokes. The measurements began during the intake stroke at a crank angle of 60° ATDC and continued until approximately 280° ATDC. The ensemble averaged LDV measurements allowed for a quantitative analysis of the dynamic in-cylinder flow process in terms of tumble and swirl motions. Both of these quantities were calculated at every 1.8 crank degrees during the described measurement interval. Tumble calculations were performed about axes in multiple planes in both the Cartesian directions perpendicular to the plane of the piston top. Swirl calculations were also accomplished in multiple planes that lie parallel to the plane of the piston top.

A diesel spray model has been developed and validated against experimental data obtained for different injection and surrounding gas conditions to allow investigation of the relative importance of the different physical processes occurring during the spray development. The model is based on the Eulerian-Lagrangian approximation and the Navier-Stokes equations, simulating the gas motion, are numerically solved on a collocated non-uniform curvilinear non-orthogonal grid, while the spray equation is solved numerically using a Lagrangian particle tracking method. The injection conditions are determined by another recently developed model calculating the flow in the fuel injection system, the sac volume and injection holes area which accounts for the details of the injection velocity, the fuel injection rate per injection hole and occurrence of hole cavitation. Thus, differences between the sprays from inclined multihole injectors can be simulated and analysed.

Spray tip penetration and dispersion in high pressure diesel engines have been simulated experimentally with a special emphasis on the effect of swirl. A constant volume chamber was designed to be rotatable in order to generate a continuous swirl and to have the flow field closely resembling a solid body rotation. Emulsified fuel was injected into the chamber and the developing process of fuel sprays was visualized. The effect of swirl on the spray tip penetration was quantified through modeling. Results show that the spray tip penetration is qualitatively different between low and high pressure injections. For high pressure injection, good agreement is achieved between the experimental results and the modeling accounting the effect of swirl on spray penetration. For low pressure injection, reasonable agreement is obtained. The modeling result can be used as basic design data in diesel injector development.

The object of this paper is to present a methodology to characterize the distribution of fuel concentration into Diesel sprays and to use it to analyze the internal dynamics and atomization/coalescence mechanisms. This methodology is based on a combination of data obtained with PDA and high speed shadowgraphy on the basis of the light extinction principle. The results of fuel concentration distribution obtained at different instants of the injection show a two zones structure. From the nozzle to approximately 70% of the tip position, the evolution of radial fuel concentration distribution is similar to a gaseous steady jet. The unsteady nature of the Diesel spray appears on the front region where an accumulation of droplets occurs, mainly in the spray axis.

An unsteady single spray of n-tridecane which was mixed with a small quantity of exciplex - forming dopants, that is naphthalene and TMPD, was impinged on a flat wall surface with high temperature of 550 K at a normal angle. These experiments were carried out in a quiescent N2 atmosphere with high temperature of 700 K and high pressure of 2.5 MPa. It was possible to generate the fluorescence emissions from the vapor and liquid phases in this spray, when a laser light sheet from a Nd:YAG laser was passing through the cross section of the spray containing its central axis. Then, clear 2 - D images of vapor and liquid phases in the spray were acquired simultaneously by this method. And, the vapor concentration was analyzed quantitatively by applying Lambert - Beer's law to the measured TMPD monomer fluorescence intensity from vapor phase, and by correcting the intensity for the effect of the quenching process due to the ambient temperature and fuel concentration.

High reinforcement content metal matrix composites are produced by the infiltration of molten Al alloys into preforms of ceramic particles using the PRIMEX™ pressureless metal infiltration process. These composites possess low density, very high specific stiffness, high fatigue strength, and good corrosion resistance, making them excellent candidates for automotive brake caliper applications. Most current production brake calipers are fabricated from ductile iron. Ductile iron provides good stiffness and fatigue strength, requirements for the application, but also possesses high density and poor corrosion resistance. The introduction of preform infiltrated metal matrix composites into brake caliper applications, however, has been slow due to the complex geometry. Low cost, high volume preform fabrication techniques suited to the production of full fist caliper preforms that can be subsequently infiltrated with molten Al alloy do not currently exist.

A semi-empirical model predicting the final rotor surface temperature under thermal steady state as a function material properties (thermal conductivity, specific heat, density), rotor thickness and test parameters (inertial load, cooling air speed) was constructed. The key observation that led to the construction of this model was that the initial rotor surface temperature during a stop varied linearly with the net temperature rise of the rotor surface during that stop of a fade sequence. The final rotor temperature under thermal steady state, Tfss (also referred to as maximum steady state temperature or MSST), is given by: Excellent agreement between the predicted and observed values Tfss of was found. This model was used to predict performance changes as a result of material modifications and can serve as an excellent tool for rotor material optimization.

Crashworthiness is a measure of a vehicle's structural integrity during mechanical impact and of its ability to absorb energy and provide occupant protection in crash situations. Finite element modeling has been successfully used to simulate collision events; the present work uses these techniques to simulate the side impact of a mid-size car in order to investigate the crash characteristics of a 45 km/hr impact. Five different analyses were conducted on orthogonal and oblique impacts under varying conditions. The numerical results from the first analysis were compared with published experimental crash results, showing favorable comparisons for this numerical model prediction.

Recently, a metal support catalyst has been successfully developed and its use has been gradually increasing because of its advantages over the conventional ceramic support. The material properties required of an automotive catalytic converter are expected to increase in severity with intensifying environmental regulations on a worldwide level. This study examined the material properties required of an Fe-Cr-Al alloy foil for a metal support having increased heat resistance. First, the effect of rare earth metals against high temperature oxidation resistance of the Fe-Cr-Al alloy foil is examined and the developed alloy is proposed. Second, the durability of the metal support is discussed. Third, the accelerated creep elongation caused by the growth of an oxide film when catalyst related material is loaded, is described and the influence on the performance of the metal support is discussed.

The A 390 (18% silicon, 1% copper Aluminum alloy) and a new designed friction material which could have a potential use in brake application have been studied on a pad-on-disk tribometer, where the pad was made of the friction material and the disk out of the hypereutectic alloy. An experimental study has allowed to optimize the formulation of the pad and the heat treatment of the disk material in order to get the best wear-properties (low wear, stable friction coefficient). Analysis have been used to understand the wear mechanisms, i.e. microstructural evolution and degradation of the material.

Effective slack associated with seat belt systems for rollover protection is studied for the purpose of improving or anticipating improvements to a motor vehicle rollover protection system. A test method and test devices were constructed to study and develop objective understandings of the effects of motor vehicle seat and seat belt characteristics on effective slack. The test devices and test method were proved in two separate motor vehicles with differing seat belt systems. Results demonstrated that effective slack as a conceptual equivalent to a seat belt webbing length could be repeatable and objectively determined for the systems tested. Determining a seat belt system's effective slack is useful for the purpose of comparing experimental restraints and experimental restraint testing to motor vehicle restraint design and performance.

Disk brake rotors require reduced unsprung weight and improved cooling ability for improved fade performance. Automotive brake rotors made from aluminum metal matrix composites (MMC) were evaluated by dynamometer and vehicle tests for the required improvement. The friction and wear performance and the thermal response during fade stops were compared with those of commercially produced gray cast iron (GCI) rotors. It was proved that MMC is a very effective material to replace GCI for brake rotor application, as it reduces unsprung weight and decreases maximum operation temperature of the brake system.