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Journal Article

Effects of Fuel Cell Material Properties on Water Management Using CFD Simulation and Neutron Imaging

2010-04-12
2010-01-0934
Effects of fuel cell material properties on water management were numerically investigated using Volume of Fluid (VOF) method in the FLUENT. The results show that the channel surface wettability is an important design variable for both serpentine and interdigitated flow channel configurations. In a serpentine air flow channel, hydrophilic surfaces could benefit the reactant transport to reaction sites by facilitating water transport along channel edges or on channel surfaces; however, the hydrophilic surfaces would also introduce significantly pressure drop as a penalty. For interdigitated air flow channel design, it is observable that liquid water exists only in the outlet channel; it is also observable that water distribution inside GDL is uneven due to the pressure distribution caused by interdigitated structure. An in-situ water measurement method, neutron imaging technique, was used to investigate the water behavior in a PEM fuel cell.
Journal Article

A Fatigue Life Prediction Method of Laser Assisted Self-Piercing Rivet Joint for Magnesium Alloys

2015-04-14
2015-01-0537
Due to magnesium alloy's poor weldability, other joining techniques such as laser assisted self-piercing rivet (LSPR) are used for joining magnesium alloys. This research investigates the fatigue performance of LSPR for magnesium alloys including AZ31 and AM60. Tensile-shear and coach peel specimens for AZ31 and AM60 were fabricated and tested for understanding joint fatigue performance. A structural stress - life (S-N) method was used to develop the fatigue parameters from load-life test results. In order to validate this approach, test results from multijoint specimens were compared with the predicted fatigue results of these specimens using the structural stress method. The fatigue results predicted using the structural stress method correlate well with the test results.
Journal Article

Considerations in HMI Design of a Reverse Braking Assist (RBA) System

2013-04-08
2013-01-0720
The Reverse Braking Assist (RBA) feature is designed to automatically activate full braking in a backing vehicle. When this feature activates, a backing vehicle is suddenly stopped or may slide to a stop. During this process, an understanding of the driver's behavior may be useful in the design of an appropriate human-machine-interface (HMI) for the RBA. Several experimental studies were done to examine driver behavior in response to an unexpected and automatic braking event while backing [1]. Two of these studies are reported in this paper. A 7-passenger Crossover Utility Vehicle was fitted with a rear-view camera, a center-stack mounted LCD screen, and ancillary recording devices. In the first study, an object was suddenly placed in the path of a backing vehicle. The backing vehicle came to a sudden and complete stop. The visual image of the backing path on the LCD prominently showed that an obstacle was present in the backing path of the vehicle.
Technical Paper

Powertrain Applications for Rapid Prototyping, Fabrication and Tooling in Motorsports

1998-11-16
983091
Rapid Prototyping, Fabrication and Tooling is a process that blends a series of technologies (machines, tools, and methods) capable of generating physical objects directly from a CAD database. The process dramatically reduces the time spent during product development by allowing for fast visualization, verification, iteration, optimization, and fabrication of parts and tools. Many new techniques of tooling have been and are being developed by using rapid fabricated parts. These are having a dramatic impact on both timing and costs throughout the automotive industry. One area that these methods can be utilized to their full potential is motorsports. Of particular interest is the growing use of bridge tooling to provide first article through production intent parts that promote cost effective changes.
Technical Paper

Adaptive Fuzzy Neural Networks With Global Clustering

2004-03-08
2004-01-0294
This paper proposes a novel algorithm. This algorithm is called Self-Organizing Fuzzy Neural Network (SOFNN). SOFNN revolutionizes how researchers apply control theories, image/signal processing on control systems and other applications. In general, SOFNN is an identification technique that automatically initiates, builds and fine-tunes the required network parameters. SOFNN evaluates required structures without predefined parameters or expressions regarding systems. SOFNN sets out to learn and configure a system's characteristics. Self-constructing and self-tuning features enable SOFNN to handle complex, non-linear, and time-varying systems with higher accuracy, making systems identification easier. SOFNN constructs and fine-tunes the system parameter through two phases. The two phases are the construction and the parameter-tuning phase. The two phases run concurrently allowing SOFNN to identify systems on-line.
Technical Paper

Gear Whine Reduction for a New Automatic Transmission

2001-04-30
2001-01-1506
Gear whine in 1st and 2nd gears in a new rear wheel drive automatic transmission was identified as a potential customer dis-satisfier. Improvements to the vehicle system were implemented, but did not sufficiently reduce the noise. CAE modeling and hardware testing were used for gear tooth optimization, transmission system, driveline, and vehicle system studies. The planetary gears were re-designed with increased contact ratio, and significant interior noise reduction was achieved; but some vehicles still had excessive noise due to gear parameter variability from multiple sources. Using a DOE and statistical studies, a set of gear parameter targets were identified within the tolerances of the design, which achieved the program objectives for noise.
Technical Paper

Analytical and Experimental Techniques in Solving the Plastic Intake Manifold NVH

2001-04-30
2001-01-1544
The intent of this paper is to summarize the work of the V8 power plant intake manifold radiated noise study. In a particular V8 engine application, customer satisfaction feedback provided observations of existing unpleasant noise at the driver's ear. A comprehensive analysis of customer data indicated that a range from 500 to 800 Hz suggests a potential improvement in noise reduction at the driver's ear. In this study the noise source was determined using various accelerometers located throughout the valley of the engine and intake manifold. The overall surface velocity of the engine valley was ranked with respect to the overall surface velocity of the intake manifold. An intensity mapping technique was also used to determine the major component noise contribution. In order to validate the experimental findings, a series of analysis was also conducted. The analysis model included not only the plastic intake manifold, but also the whole powertrain.
Technical Paper

An Advanced Instrument for the Real Time Measurement of Engine Oil Economy

1992-02-01
920655
A number of advancements have been made in the coulometric sulfur trace instrumental technique for the real-time measurement of engine oil economy. These advancements include modification of the coulometric cell to improve reliability and reproducibility. The instrument has been interfaced with a microcomputer for instrument control as well as data acquisition, storage, and analysis. Studies were undertaken which demonstrate sufficient sensitivity and linearity for determination of engine oil economy at levels better than 10,000 miles/quart. Applications to steady-state engine oil consumption mapping and to instantaneous oil consumption during transient engine cycling are described. These instruments are being produced by an outside supplier for use in various company locations in both the engine production and engine research environments.
Technical Paper

Correlation of Dominant Noise Transfer Paths in Statistical Energy Analysis Vehicle Model from Test as Basis for Variant Vehicle Development

2013-05-13
2013-01-1994
For purposes of reducing development time, cost and risk, the majority of new vehicles are derived strongly or at least generally from a surrogate vehicle, often of the same general size or body style. Previous test data and lessons learned can be applied as a starting point for design of the new vehicle, especially at early phases of the design before definite design decisions have been finalized and before prototype of production test hardware is available. This is true as well of vehicle NVH development where most new vehicles being developed are variants of existing vehicles for which the main noise transfer paths from sources of interest are already understood via test results and existing targets. The NVH targets for new vehicles are defined via benchmarking, market considerations, and other higher-level decisions. The objective is then to bridge the gap between test data from surrogate vehicles to direct support of the NVH development of new vehicle programs.
Technical Paper

Controlling Panel Noise and Vibration Using Non-Contacting Test Methodologies

1993-05-01
931339
Non-contacting test methodology studies of automotive body components have become a very useful, high resolution and sensitive test technique to engineering personnel. Continuous wave laser holometry, computer aided holometry (CAH), pulsed laser holometry and a scanning laser system were used to image vibration patterns. These methods were selected because of improved data turn-around time in the test development process while having no mass-loading effects on the sheet metal panels. An analysis of the vehicle body structure was conducted to improve the interior body structure sound quality and to reduce road noise presence. An interrogation of the interior noise spectrum identified critical frequencies affecting vehicle NVH. This paper addresses the results of using the aforementioned non-contacting test methods to reduce panel responses by developing an optimum rib section and pattern, and the addition of adhered stiffening materials.
Technical Paper

Optical Methods Aid for Visualization of Convective Heat Flow Patterns

1994-03-01
940503
The use of Shadowgraph and Schlieren optical systems is a simple method to determine flow patterns of heated air external to the vehicle at idle. In particular, the method can be used to visualize natural convective air flow patterns at the underbody to aid in heat shielding design. Moreover, air recirculation patterns around the front end of the vehicle can be visualized without the use of smoke. The optical equipment is described and recommendations proposed for setting up the equipment. A video tape of some results is also presented.
Technical Paper

Use of Experimentally Measured In-Cylinder Flow Field Data at IVC as Initial Conditions to CFD Simulations of Compression Stroke in I.C. Engines - A Feasibility Study

1994-03-01
940280
The feasibility of using experimentally determined flow fields at intake valve closing, IVC, as initial conditions for computing the in-cylinder flow dynamics during the compression stroke is demonstrated by means of a computer simulation of the overall approach. A commercial CFD code, STAR-CD, was used for this purpose. The study involved two steps. First, in order to establish a basis for comparison, the in-cylinder flow field throughout the intake and compression strokes, from intake valve opening, IVO, to top dead center, TDC, was computed for a simple engine geometry. Second, experimental initial conditions were simulated by randomly selecting and perturbing a set of velocity vectors from the computed flow field at IVC.
Technical Paper

Characterization of Intake-Generated Flow Fields in I.C. Engines Using 3-D Particle Tracking Velocimetry (3-D PTV)

1994-03-01
940279
Flow fields generated during the intake stroke of a 4-stroke I.C. engine are studied experimentally using water analog simulation. The fluid is seeded by small flow tracer particles and imaged by two digital cameras at BDC. Using a 3-D Particle Tracking Velocimetry technique recently developed, the 3-D motion of these flow tracers is determined in a completely automated way using sophisticated image processing and PTV algorithms. The resulting 3-D velocity fields are ensemble averaged over a large number of successive cycles to determine the mean characteristics of the flow field as well as to estimate the turbulent fluctuations. This novel technique was applied to three different cylinder head configurations. Each configuration was run for conditions simulating idle operation two different ways: first with both inlet ports open and second with only the primary port open.
Technical Paper

A Comparison of Total and Speciated Hydrocarbon Emissions from an Engine Run on Two Different California Phase 2 Reformulated Gasolines

1994-10-01
941972
New regulations from the state of California have established, for the first time, reactivity-based exhaust emissions standards for new vehicles and require that any clean alternative fuels needed by these vehicles be made available. Contained in these regulations are provisions for “reactivity adjustment factors” which will provide credit for vehicles which run on reformulated gasoline. The question arises: given two fuels of different chemical composition, but both meeting the criteria for CA Phase 2 gasoline (reformulated gasoline), how different might the specific reactivity of the exhaust hydrocarbons be? In this study we explored this question by examining the engine-out HC emissions from a single-cylinder version of the 5.4 L modular truck engine run on two different CA Phase 2 fuels.
Technical Paper

Laser Ride Height Measurement/Calibration System

1995-02-01
950025
The Laser Ride Height Measurement and Calibration System measures and calibrates the ride height of a vehicle equipped with electronic suspension. The existing process of setting ride height is labor intensive and imprecise leading to vehicles that lean, have improper attitude, and suffer from alignment drift and pull. The proposed Machine and Process will impart the correct appearance and ride height to every vehicle which undergoes this test. A similar process can be used to measure the ride height of vehicles equipped with passive springs.
Technical Paper

Experimental Analysis of Interior Noise Due to Powerplant Radiated Noise

1995-05-01
951266
Vehicle interior noise due to powerplant radiation is a product of two factors, the noise level radiated by the powerplant and the effectiveness of the vehicle body and sound package in reducing this noise. Effective noise reduction strategies require that the appropriate target levels be set for these factors. This paper reviews studies performed at Ford to establish such targets and the theoretical basis of these studies. To set sound package targets engine noise simulators have been used to study the sound package noise reduction capabilities of various vehicles. These studies include the effect of noise source location on attenuation, the effect of powerplant location and dimensions, and the effect of interior microphone location. Engine noise targets are being established by testing powerplants in the hemi-anechoic dynamometer test cells of the new AEC Building. Studies include the effect of engine rpm, load, and microphone location.
Technical Paper

Customer Based Holometric Analysis

1995-05-01
951308
This paper describes a test-based process used to identify structural characteristics of a vehicle windshield wiper system that contribute to customer impression of the sound. The method of paired comparisons determined which wiper system sounds customers preferred. Annoyance ratings of sound components then identified contributors to customer preference. Wiper motor noise was identified as the major annoyance factor affecting system sound quality. This information guided a study of the structures responsible for radiated motor noise. Laser based test methods were used to interrogate the structures clearly identifying transmission paths into the surrounding structure. Paths were then modified reducing structure-borne motor sound as measured with acoustic retests. Thus, a logical technique for hardware testing and modification guided by customer perceptions is presented allowing efforts to be focussed on the most critical aspects of vehicle sound quality.
Technical Paper

Measurement of Aeroacoustically Induced Door Glass Vibrations Using a Laser Vibrometer

1995-05-01
951331
Work has been performed to study side glass vibrations of a typical automobile using a scanning laser vibrometer. The objective of this work was to achieve better understanding of the source and path mechanisms for aeroacoustically generated wind noise. As a tool for measuring aeroacoustically generated vibrations, the laser vibrometer presents many advantages over traditional methods. These advantages, discussed in this paper, include rapid setup, full field imaging, high spacial resolution, non-contact operation, and wide dynamic and frequency ranges.
Technical Paper

Blower Motor Whining Noise - A Case Study

1995-05-01
951349
Vehicle interior sound quality is regarded as a major quality attribute by automobile consumers and manufacturers. Whining noise, due to its steady state and tonal nature, is easily perceived as an annoyance to normal driving comfort. The blower motor in the climate control air-handling system can be a source of whining noise, especially when the motor is located in the passenger compartment. This paper describes a systematic case study carried out to identify the major noise generating mechanisms of a whining noise from the climate control air-handling system. The paper discusses the use of commonly available tools and techniques to resolve typical automotive NVH concerns resulting in improved sound quality. Particular measurement and analysis techniques presented include sound field mapping using acoustic intensity, resonance identification using transfer functions, three-axis spectrum analysis, and some physical modifications to the source and propagation paths.
Technical Paper

Fuel Spray Characterisation within an Optically Accessed Gasoline Direct Injection Engine Using a CCD Imaging System

1996-05-01
961149
A test facility was constructed at University College London to study fuel spray structure within a gasoline direct injection engine. The facility consisted of a single cylinder research engine with extensive optical access and a novel video imaging and analysis system. The engine used an experimental prototype 4-valve cylinder head with direct in-cylinder high pressure fuel injection, provided by a major automotive manufacturer. The fuel spray was illuminated using a pulsed copper-vapour laser. Results are presented that illustrate the spray behaviour within the fired research engine. A laser light sheet provided an insight into the inner spray cone behaviour.
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