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Technical Paper

Transient Cavitating Flow Simulations Inside a 2-D VCO Nozzle Using the Space-Time CE/SE Method

2001-05-07
2001-01-1983
Cavitating flows inside a two-dimensional valve covered orifice (VCO) nozzle were simulated by using the Space-Time Conservation Element and Solution Element (CE/SE) method in conjunction with a homogeneous equilibrium cavitation model. As a validation for present model, cavitation over a NACA0015 hydrofoil was predicted and compared with previous simulation results as well as experimental observations. The model was then used to investigate the effects on internal cavitating flows of different nozzle design parameters, such as the hole size, hole aspect-ratio, hydro-erosion radius, and orifice inclination. Under different conditions, cavitating flows through fuel injectors generated hydraulic flip, supercavitation, full cavitation, and cyclical cavitation phenomena, which are commonly observed in experiments.
Technical Paper

The Burning Velocity in a CFR Engine with Different Turbulent Flow Fields Generated by Intake Valves

1980-06-01
800860
An equation has been derived to calculate the burning velocity in a CFR engine from the measured flame speed under different turbulent flow fields. The turbulence is generated during the intake stroke as the fresh charge flows through different perforated 360° shrouded intake valves. The shrouds have holes of different sizes, but of the same total flow area. Results show that these valves decrease the cycle-to-cycle variation and produce higher burning velocities than conventional valves, particularly at higher engine speeds. The burning velocity depends on the Reynolds number as well as the turbulence scale.
Journal Article

Shell Elements Based Parametric Modeling Method in Frame Robust Design and Optimization

2011-04-12
2011-01-0508
Shell Elements based Parametric Frame Modeling is a powerful CAE tool, which can generate robust frame design concept optimized for NVH and durability quickly when combined with Taguchi Design of Experiments. The scalability of this modeling method includes cross members length/location/section/shape, frame rail segments length/section and kick in/out/up/down angle, and access hole location & size. In the example of the D. O. E. study, more than fifteen parameters were identified and analyzed for frequency and weight. The upper and lower bounds were set for each design parameter based on package and manufacturing constraints. Sixteen Finite Element frame were generated by parametrically updating the base model, which shows this modeling method is comparatively convenient. Sensitivity of these sixteen parameters to the frequency and weight was summarized through statics, so the favorable design alternative can be achieved with the major parameters' combination.
Technical Paper

Safe Interaction for Drivers: A Review of Driver Distraction Guidelines and Design Implications

2015-04-14
2015-01-1384
In this age of the Internet of Things, people expect in-vehicle interfaces to work just like a smartphone. Our understanding of the reality of in-vehicle interfaces is quite contrary to that. We review the fundamental principles and metrics for automotive visual-manual driver distraction guidelines. We note the rise in portable device usage in vehicles, and debunk the myth of increased crash risk when conversing on a wireless device. We advocate that portable electronic device makers such as Apple and Google should adopt driver distraction guidelines for application developers (whether for tethered or untethered device use in the vehicle). We present two design implications relevant to safe driving. First, the Rule of Platform Appropriateness: design with basic principles of ergonomics, and with driver's limited visual, manual and cognitive capacity, in mind. Second, the Rule of Simplicity: thoughtful reduction in the complexity of in-vehicle interfaces.
Technical Paper

Reciprocating Engine Piston Secondary Motion - Literature Review

2008-04-14
2008-01-1045
The piston secondary motion is an important phenomenon in internal combustion (IC) engine. It occurs due to the piston transverse and rotational motion during piston reciprocating motion. The piston secondary motion results in engine friction and engine noise. There has been lot of research activities going on in piston secondary motion using both analytical models and experimental studies. These studies are aimed at reducing the engine friction as well as the noise generated due to piston secondary motion. The aim of this paper is to compile the research actives carried out on the piston secondary motion and discuss the possible research opportunities for reducing the IC engine piston secondary motion.
Technical Paper

On the Development of a New Design Methodology for Vehicle Crashworthiness based on Data Mining Theory

2016-04-05
2016-01-1524
This paper represents the development of a new design methodology based on data mining theory for decision making in vehicle crashworthy components (or parts) development. The new methodology allows exploring the big crash simulation dataset to discover the underlying complicated relationships between vehicle crash responses and design variables at multi-levels, and deriving design rules based on the whole vehicle safety requirements to make decisions towards the component and sub-component level design. The method to be developed will resolve the issue of existing design approaches for vehicle crashworthiness, i.e. limited information exploring capability from big datasets, which may hamper the decision making and lead to a nonoptimal design. A preliminary design case study is presented to demonstrate the performance of the new method. This method will have direct impacts on improving vehicle safety design and can readily be applied to other complex systems.
Technical Paper

Numerical Study of Ultra Low Solidity Airfoil Diffuser in an Automotive Turbocharger Compressor

2009-04-20
2009-01-1470
For the application of advanced clean combustion technologies, such as diesel HCCI/LTC, a compressor with high efficiency over a broad operation range is required to supply a high amount of EGR with minimum pumping loss. A compressor with high pitch of vaneless diffuser would substantially improve the flow range of the compressor, but it is at the cost of compressor efficiency, especially at low mass flow area where most of the city driving cycles resides. In present study, an ultra low solidity compressor vane diffuser was numerically investigated. It is well known that the flow leaving the impeller is highly distorted, unsteady and turbulent, especially at relative low mass flow rate and near the shroud side of the compressor. A conventional vaned diffuser with high stagger angle could help to improve the performance of the compressor at low end. However, adding diffuser vane to a compressor typically restricts the flow range at high end.
Journal Article

Modeling and Validation of Rapid Prototyping Related Available Workspace

2014-04-01
2014-01-0751
Path planning and re-planning for serial 6 degree of freedom (DOF) robotic systems is challenging due to complex kinematic structure and application conditions which affects the robot's tool frame position, orientation and singularity avoidance. These three characteristics represent the key elements for production planning and layout design of the automated manufacturing systems. The robot trajectory represents series of connected points in 3D space. Each point is defined with its position and orientation related to the robot's base frames or predefined user frame. The robot will move from point to point using the desired motion type (linear, arc, or joint). The trajectory planning requires first to check if robot can reach the selected part(s). This can be simply done by placing the part(s) inside the robot's work envelope. The robot's work envelope represents a set of all robots' reachable points without considering their orientation.
Journal Article

Methods for Evaluating the Functional Work Space for Machine Tools and 6 Axis Serial Robots

2016-04-05
2016-01-0338
The ‘boundary of space’ model representing all possible positions which may be occupied by a mechanism during its normal range of motion (for all positions and orientations) is called the work envelope. In the robotic domain, it is also known as the robot operating envelope or workspace. Several researchers have investigated workspace boundaries for different degrees of freedom (DOF), joint types and kinematic structures utilizing many approaches. The work envelope provides essential boundary information, which is critical for safety and layout concerns, but the work envelope information does not by itself determine the reach feasibility of a desired configuration. The effect of orientation is not captured as well as the coupling related to operational parameters. Included in this are spatial occupancy concerns due to linking multiple kinematic chains, which is an issue with multi-tasking machine tools, and manufacturing cells.
Journal Article

Jaw Loading Response of Current ATDs

2009-04-20
2009-01-0388
Biomechanical surrogates are used in various forms to study head impact response in automotive applications and for assessing helmet performance. Surrogate headforms include those from the National Operating Committee on Standards for Athletic Equipment (NOCSAE) and the many variants of the Hybrid III. However, the response of these surrogates to loading at the chin and how that response may affect the loads transferred from the jaw to the rest of the head are unknown. To address part of that question, the current study compares the chin impact response performance of select human surrogates to that of the cadaver. A selection of Hybrid III and NOCSAE based surrogates with fixed and articulating jaws were tested under drop mass impact conditions that were used to describe post mortem human subject (PMHS) response to impacts at the chin (Craig et al., 2008). Results were compared to the PMHS response with cumulative variance technique (Rhule et al., 2002).
Journal Article

Iterative Learning Control for a Fully Flexible Valve Actuation in a Test Cell

2012-04-16
2012-01-0162
An iterative learning control (ILC) algorithm has been developed for a test cell electro-hydraulic, fully flexible valve actuation system to track valve lift profile under steady-state and transient operation. A dynamic model of the plant was obtained from experimental data to design and verify the ILC algorithm. The ILC is implemented in a prototype controller. The learned control input for two different lift profiles can be used for engine transient tests. Simulation and bench test are conducted to verify the effectiveness and robustness of this approach. The simple structure of the ILC in implementation and low cost in computation are other crucial factors to recommend the ILC. It does not totally depend on the system model during the design procedure. Therefore, it has relatively higher robustness to perturbation and modeling errors than other control methods for repetitive tasks.
Technical Paper

Investigation of Diesel Spray Primary Break-up and Development for Different Nozzle Geometries

2002-10-21
2002-01-2775
The nozzle configuration for an injector is known to have an important effect on the fuel atomization. A comprehensive experimental and numerical investigation has been performed to determine the influence of various internal geometries on the primary spray breakup and development using the electronically controlled high-pressure diesel injection systems. Different types of multi-hole minisac and VCO nozzles with cylindrical and tapered geometries, and different types of single-hole nozzles with defined grades of Hydro Grinding (HG) were investigated. The global characteristics of the spray, including spray angle, spray tip penetration and spray pattern were measured from the spray images with a high-speed drum camera. A long-distance microscope with a pulsed-laser as the optical shutter was used to magnify the diesel spray at the nozzle hole vicinity. A CFD analysis of the internal flow through various nozzle geometries has been carried out with a commercial code.
Technical Paper

Institute for Manufacturing Research, Wayne State University

1998-05-12
981345
The purpose of the Institute for Manufacturing Research (IMR) is to enhance Wayne State University's existing technological strength in the areas of manufacturing research which have demonstrated potential benefits for the State's economy. IMR's faculty conduct basic and applied research in selected areas of manufacturing science. The research programs within the Institute are broadly interdisciplinary and industrially interactive, and are organized around the following areas: materials development, modification, and nondestructive evaluation; software technology for manufacturing and engineering; and product reliability and machine tool research. Faculty from eight departments within the Colleges of Science and Engineering participate in IMR.
Technical Paper

Innovative Graduate Program in Mechatronics Engineering to Meet the Needs of the Automotive Industry

2010-10-19
2010-01-2304
A new inter-disciplinary degree program has been developed at Lawrence Technological University: the Master of Science in Mechatronic Systems Engineering Degree (MS/MSE). It is one of a few MS-programs in mechatronics in the U.S.A. today. This inter-disciplinary program reflects the main areas of ground vehicle mechatronic systems and robotics. This paper presents areas of scientific and technological principles which the Mechanical Engineering, Electrical and Computer Engineering, and Math and Computer Science Departments bring to Mechatronic Systems Engineering and the new degree program. New foundations that make the basis for the program are discussed. One of the biggest challenges was developing foundations for mechanical engineering in mechatronic systems design and teaching them to engineers who have different professional backgrounds. The authors first developed new approaches and principles to designing mechanical subsystems as components of mechatronic systems.
Technical Paper

Injury Tolerance Characteristics of the Adult Human Lower Extremities Under Static and Dynamic Loading

1986-10-01
861925
A review of the literature dealing with the injury tolerance of the lower extremities in quantitative terms is provided. The data stem from sources ranging from Weber (1859) to as recent as Culver (1984) and in all cases involve tests of embalmed or unembalmed cadaveric specimens. The strength of the femur (thigh bone) and tibia (shin bone) have been depicted primarily in terms of the peak axial compressive force or bending moment associated with fracture-producing tests. Peak forces involved in fracturing the patella (knee cap) are reported for static and dynamic distributed loads involving both padded and rigid contact surfaces. One study is described where patella data are available for punch-through type fractures resulting from loading by small diameter impactors. Limited data are provided for hip joint dislocation and/or pelvic fracture as a result of loading through the femur. Finally, limited data are also included for injury at the knee and ankle joints.
Technical Paper

Implications of 3-D Internal Flow Simulation on the Design of Inward-Opening Pressure-Swirl Injectors

2002-10-21
2002-01-2698
A parametric study on the effects of critical injector design parameters of inwardly-opening pressure-swirl injectors was carried out using 3-D internal flow simulations. The pressure variation and the integrated momentum flux across the injector, as well as the flow distributions and turbulence structure at the nozzle exit were analyzed. The critical flow effects on the injector design identified are the swirler efficiency, discharge coefficient, and turbulence breakup effects on the spray structure. The study shows that as a unique class of injectors, pressure-swirl injectors is complicated in fluid mechanics and not sufficiently characterized or optimized. The swirler efficiency is characterized in terms of the trade-off relationship between the swirl-to-axial momentum-flux ratio and pressure drop across the swirler. The results show that swirl number is inversely proportional to discharge coefficient, and that hole diameter and swirler height is the most dominant parameters.
Technical Paper

GDi Skew-Angled Nozzle Flow and Near-Field Spray Analysis using Optical and X-Ray Imaging and VOF-LES Computational Fluid Dynamics

2013-04-08
2013-01-0255
Improvement of spray atomization and penetration characteristics of the gasoline direct-injection (GDi ) multi-hole injector is a critical component of the GDi combustion developments, especially in the context of engine down-sizing and turbo-charging trend that is adopted in order to achieve the European target CO₂, US CAFE, and concomitant stringent emissions standards. Significant R&D efforts are directed towards optimization of the nozzle designs, in order to improve the GDi multi-hole spray characteristics. This publication reports VOF-LES analyses of GDi single-hole skew-angled nozzles, with β=30° skew (bend) angle and different nozzle geometries. The objective is to extend previous works to include the effect of nozzle-hole skew angle on the nozzle flow and spray primary breakup. VOF-LES simulations of a single nozzle-hole of a purpose-designed GDi multi-hole seat geometry, with three identical nozzle-holes per 120° seat segment, are performed.
Technical Paper

GDi Nozzle Parameter Studies Using LES and Spray Imaging Methods

2014-04-01
2014-01-1434
Development of in-cylinder spray targeting, plume penetration and atomization of the gasoline direct-injection (GDi) multi-hole injector is a critical component of combustion developments, especially in the context of the engine downsizing and turbo-charging trend that has been adopted in order to achieve the European target CO2, US CAFE, and concomitant stringent emissions standards. Significant R&D efforts are directed towards the optimization of injector nozzle designs in order to improve spray characteristics. Development of accurate predictive models is desired to understand the impact of nozzle design parameters as well as the underlying physical fluid dynamic mechanisms resulting in the injector spray characteristics. This publication reports Large Eddy Simulation (LES) analyses of GDi single-hole skew-angled nozzles, with β=30° skew (bend) angle and different nozzle geometries.
Technical Paper

Experimental Analysis of Dynamics and Friction in Valve Train Systems

2002-03-04
2002-01-0484
The paper analyses the friction in the valve train of an internal combustion engine trying to separate the contribution of the different components to the total friction losses in the valve train. The measurements are performed on a running engine in order to avoid extraneous factors introduced by simulating rigs. The experimental engine is instrumented with strain gauge bridges on the rocker arm, the push rod and the camshaft to measure forces and moments acting on these components. Original techniques are developed to isolate and determine the friction forces between the valve stem and its guide, the friction force in the rocker arm bearing and the combined friction between cam/tappet and tappet/bore. It was found that the friction in the rocker arm bearing never reaches hydrodynamic conditions and that the friction coefficient between cam and tappet reduces with an increase in the engine speed.
Technical Paper

Effects of Sinusoidal Whole Body Vibration Frequency on Drivers' Muscle Responses

2015-04-14
2015-01-1396
Low back pain has a higher prevalence among drivers who have long term history of vehicle operations. Vehicle vibration has been considered to contribute to the onset of low back pain. However, the fundamental mechanism that relates vibration to low back pain is still not clear. Little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to determine the vibration frequency that causes the increase of muscle activity that can lead to muscle fatigue and low back pain. This study investigated the effects of various vibration frequencies on the lumbar and thoracic paraspinal muscle responses among 11 seated volunteers exposed to sinusoidal whole body vibration varying from 4Hz to 30Hz at 0.4 g of acceleration. The accelerations of the seat and the pelvis were recorded during various frequency of vibrations. Muscle activity was measured using electromyography (EMG).
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