Search Results

Due to their inherent high efficiency and the ease of starting once the engine is hot, turbocharged direct injection (TDI) diesel engines have emerged as one of the contending powerplants for PNGV hybrid vehicles. The interest in applying diesel engines in hybrid vehicles has prompted the modeling of direct injection diesel engine fuel consumption. The empirical equation developed in this study, which models engine friction and indicated efficiency as functions of engine operating speed and load, shows excellent agreement with test data gathered from public sources. The engine speed dependence of the friction and indicated efficiency are determined by fitting available data. Several assumed load dependences are considered. (If public data were available on engine cylinder pressure by crank angle as a function of engine speed and load, the load dependence could be determined empirically.)

A complete finite element model of the BioSID side impact dummy was created using the finite element code RADIOSS. The objective of this work was to develop an accurate and stable dummy model, which can capture the dummy behavior due to a localized impact or in a full-scale side impact finite element model with reasonable CPU time. This warranted the development of a detailed dummy model which reflects the BioSID geometrically and has material characteristics similar to the physical dummy. This paper describes the stages of the model development and discusses the issues which influence the accuracy of the dummy model predictions. It also shows comparisons of the dummy model responses and kinematics with a series of sled test data and calibration tests specified in the BioSID User's Manual.

The combustion of diesel fuels injected into a bomb at 25 bar and 520°C has been modelled and studied experimentally using laser diagnostics. A CFD model of diesel spray injection was combined with a database of results from a detailed chemical kinetic model. All fuels showed the presence of small aromatics throughout combustion (i.e. the fuel aromatics were not completely broken down). The model gave good agreement on spray penetrations and soot volume fractions around the edges of the spray. Far from the spray, the model over-predicted the amount of soot due to the absence of an OH oxidation mechanism in the CFD code. This demonstrates the need to progress to the use of a reduced chemistry scheme.

Conformability Analysis is a structured technique which seeks to identify potential problems in the manufacture and assembly of the parts and expresses the outcome as a cost of quality for the design. The analysis provides process capability estimates based on key features of parts. Considerations of the severity of possible failure of each part enables this process risk to be mapped onto a cost model to assess the expected cost of failure. Given the very high proportion of product cost determined very early in a project, and the typically significant quality costs incurred, such an approach to design evaluation is important in the product introduction process. Applications illustrate how the method is used to evaluate, compare or generate designs and show how awareness of process capability is raised in the team and in discussions with suppliers.

This paper provides an exposition of the basic and some refined inertial critical speed estimation formulas. A literature review of existing inertial formulas for estimating critical cornering speed were identified for the ultimate purpose of developing a useful, compact, and more accurate speed estimation formula. Background information is presented covering the general definitions and utility of critical speed formulas. First, as a point of reference, the basic critical speed formulas are derived. Included is a list of the key assumptions on which the basic formulas are based. It is shown that the basic formulas are founded on the fundamental principles of physics and engineering mechanics; namely, Newton's Second Law and centrifugal force.

This paper covers briefly the theory of tire-road friction, coefficient of friction measurement techniques, and the vagaries of tire-road friction as they relate to critical speed estimation. A literature review of tire-road friction studies was conducted to identify the primary factors effecting the tire-road coefficient of friction. Background information is presented covering general definitions and the connection between the basic critical speed formulas and the coefficient of friction. The primary components of tire-road friction, adhesion and hysteresis, are discussed along with minor effects such as tearing, wear, waves, and roll formation. Common coefficient of friction field measuring techniques are described, including the skid-to-stop test and drag sled. Influential factors such as tire characteristics, tire inflation pressure, road conditions, and dynamic factors are reviewed.

The permeability of some airbag fabrics is determined, along with the Ergun coefficient signifying departure from purely viscous flow, from gas flow rates and pressure drop measurements. The dependency of these coefficients on the fabric temperature is also examined. Preliminary results are reported on the transient response of these fabrics to temporal changes in the gas flow rate and temperature. The temperature history is measured and compared with the predictions of some simple models. The models make various assumptions regarding the microscale of the fabrics. The preliminary results show that the very fine microscales do not control the time response of the fabric.

The objective of this study was to determine dynamic tensile characteristics of various door trim materials and to recommend a practical test methodology. In this study, Polypropylene (PP) and Acrilonitryl Butadiene Styrene (ABS) door trim materials were tested. Slow speed (quasi-static-0.021 mm/s) and high speed tests were conducted on a closed loop servo-hydraulic MTS system. The maximum stress of these materials increased from quasi-static to dynamic test conditions (as much as 100%). The dynamic stiffness of PP increased two times from quasi-static tests. No significant change in stiffness was observed for ABS during quasi-static and dynamic tests at different strain-rates. Quasi-static and medium strain-rate (10-20 mm/mm/s) tests may be adequate in providing data for characterizing the dynamic behavior of trim materials for CAE applications. Strain gages can be used to measure the quasi-static and in some cases, dynamic strain.

It is demonstrated that direct air injection leads to substantial improvement of the cold starting performance of an SI engine. Raw pollutant formation is considerably reduced and fuel conversion efficiency increased. Air is directly injected into the cylinder through a small orifice during the compression stroke. Optical measurement techniques, in particular Spontaneous Raman Scattering, are applied to elucidate the in-cylinder processes that lead to improved cold starting perfomance. It is demonstrated that air injection causes enhanced combustion via increased turbulence and this leads to rapid warm-up of the combustion chamber walls. Thus the quality of the combustion process after the first few cycles is comparable to warmed-up engine operating conditions. It turned out to be possible to avoid fuel-enrichment and start the engine with lean fuel/air mixture (at 20°C).

A new orifice plate (OP) for advanced fuel injection characteristics is presented. The OP is designed to optimize the air-fuel mixture generation and transportation within individually shaped manifold geometries of spark-ignition engines. To generate the suitable spray characteristics, the basic OP design and its flow characteristics have some features originating from the well known turbulence nozzle principle: Turbulence generating flow deflections within the OP are achieved by superimposing layers containing flow cavities, which are displaced from one another. The flow deflections effect atomization and define the spatial spray beam orientation. A great variety and a high volume of precisely structured, low cost OPs can be produced daily by micromachining the layers in electroformed nickel. The flow cavities and outer dimensions of each layer are shaped by photo-resist structures.

Foamed materials and rubbery materials have been commonly used as energy absorbers in automotive safety designs. The present study investigates the response of polyurethane, vinyl, and their laminations with aluminum panels under low-velocity impact. In addition to force history and force-deflection relation, impact parameters such as peak force, contact duration, maximum deflection, and energy absorption capability are of primary concerns. Experimental results reveal that the lamination sequence affects the impact parameters significantly, LS-DYNA3D is also used to verify the experimental findings.

The child dummy is seeing increased use in car crash testing for safety reasons. A neck of the child dummy is one of the key components for dummy design, manufacturing and testing. The testing corridor would affect the all of the procedure for the neck. This paper would discuss the testing corridor for neck calibration of the child dummy. The testing corridors should be come from biomechanical results and combine with the material property. The paper has reviewed the research result and described the dummy neck of Six-Month, Twelve-Month, Eighteen-Month Old Infant (CRABI); Three-Year Old and Six-Year Hybrid III Child (Hybrid II Child dummy will not be discussed in the paper). A series of testing has been done for finding out corridors of the neck pendulum calibrating tests. It is difficulty to match the human corridors of crash reaction. There are several methods to approach the child neck corridors such as change design, adjust testing parameter and so on.

There is currently an urgent need in the automotive industry to demonstrate the recycling capabilities of polyurethanes (PU) into the same application. This paper describes a new technology which allows up to 12% of an energy-absorbing PU foam to be directly recycled into new parts. This recycle content has been achieved by incorporating foam regrind as a filler into the B side polyol blend. This new technology has demonstrated that Bayer's Bayfill® EA-4003 can be effectively reproduced with a regrind content of up to 12%. The resulting filled product has physical properties, processing characteristics and densities comparable to unfilled foams made with virgin materials.

A small, low-cost damper is developed to attenuate fuel rail pulsation caused by hydraulic hammer. Rail hammer is of special concern when using returnless fuel systems, affecting emissions, drive-ability, and creating noise. The new development, utilizing a springbiased diaphragm damper, replaces the fuel line connector serving the rail. High performance damping is achieved through a unique design permitting significant mass, volume, and cost savings. The low mass and the packaging advantage of the new damper permit additional system cost savings by eliminating the conventional rail interface components and labor. This function integrated into the fuel line connector of the rail permits pulsation damping to be added to an existing system without rail modification and without additional fuel connections, thereby maintaining the system's integrity with respect to hydrocarbon permeation and leakage.

Many of the current issues surrounding the achievement of accurate fuel level indication and fuel sensor design strategy revolve around systems issues, but are most often treated as component deficiencies. This paper takes a “systems” look at liquid fuel level indication as opposed to the traditional “component” view. The intent of the author is to present a framework of system considerations relative to the task of designing a robust fuel level indication system in the automobile.

Polyacrylate elastomers are currently manufactured by polymer suppliers in Italy, Japan and United States to fulfil oil resistance requirement of automotive industry. However aging conditions have significantly changed over the years so that updated experimental results are demanded by industry along with new generation products showing enhanced properties. As an example, no-post cure polyacrylic rubbers are today available to satisfy their users' processablity concerns.

We studied new-type heat-resistanct elastomers. They are based on fluoroelastomer/ acrylic-elastomer blands. Their heat resistance temperature for long term use are about 175°C. They are graded E to F class for heat resistance and G to H class for oil resistance within the ASTM D2000/SAE J200 framework. In this presentation, newly developed elastomers are discussed.

Many foams exhibit significant strain rate dependency in their mechanical responses. To characterize these foams, a strain rate dependent constitutive model is formulated and implemented in an explicit dynamic finite element code developed at FORD. The constitutive model is developed in conjunction with a Lagrangian eight node solid element with twenty four degrees of freedom. The constitutive model has been used to model foams in a number crash analysis problems. Results obtained from the analyses are compared to the experimental data. Evidently, numerical results show excellent agreement with the experimental data.

The New U.S. Evaporative Emission Regulations, which set forth the level of hydrocarbon evaporation generated from vehicles, have been applied in the industry since 1994. In order to meet the Regulations, the filler hose is required to be made for a one tenth of the gasoline permeability of that for conventional filler hose, without design change. The fuel filler hose must also provide a flexible configuration, such as a bellowed or a complicatedly curved shape In order to cope with the problems above, the Author, et al, have successfully developed A LOW PERMEATION FUEL FILLER HOSE which has a high freedom of configuration. During the first stage of development, the Author, et al, developed a hose of 2-layer structure using FKM rubber for inner layer as the permeation barrier, which is applicable in the bellow shape, by means of a unique molding technique.

The new vehicle generations will have electronic architectures much more complex than we thought some years ago. This presentation should give a status and an outline of future electronic solutions in powertrain control.