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Technical Paper

A Building for Testing European Rovers and Landers under Simulated Surface Conditions: Part 1 - Design and Phasing

2008-06-29
2008-01-2021
Europe has embarked on a new programme of space exploration involving the development of rover, lander and probe missions to visit planets, moons and near Earth objects (NEOs) throughout the Solar System. Rovers and landers will require testing under simulated planetary, and NEO conditions to ensure their ability to land on and traverse the alien surfaces. ESA has begun work on a building project that will provide an enclosed and controlled environment for testing rover and lander functions such as landing, mobility, navigation and soil sampling. The facility will first support the European ExoMars mission due for launch in 2013. This mission will deliver a robotic rover to the Martian surface. This paper, the first of several on the project, gives an overview of its design configuration and construction phasing. Future papers will cover its applications and operations.
Technical Paper

A CFD Model with Optical Validation on In-cylinder Charge Performances of CAI Engines

2008-04-14
2008-01-0045
Over the past few decades, Homogeneous Charge Compression Ignition (HCCI) or Controlled Auto-Ignition (CAI) if it is fuelled with gasoline type of fuels has shown its potential to overcome the limitations and environmental issue concerns of the Spark Ignition (SI) and Compression Ignition (CI) engines. However, controlling the ignition timing of a CAI engine over a wide range of speeds and loads is challenging. Combustion in CAI is affected by a number of factors; the local temperature, the local composition of the air/fuel mixture, time and to a lesser degree the pressure. The in-cylinder engine charge flow fields have significant influences on these factors, especially the local gas properties, which leads to the influences towards the CAI combustion. In this study, such influences were investigated using a Computational Fluid Dynamics (CFD) engine simulation package fitted with a real optical research engine geometry.
Technical Paper

A Cartridge Type Pivotal Pin and Bushing Joint

1982-02-01
820636
A cartridge type pivotal pin and bushing joint has been patented and is being tested and refined both in the laboratory and on construction machinery. It features “dry lubricated” (Teflon) bearings which are assembled and sealed prior to installation. It is suitable for heavy unit loads and use under severe wear conditions, such as in crawler track chains and loader bucket pivotal pin joints. A brief history of U. S. manufactured track pin joints is included to show the progress in extending the service life of these devices.
Technical Paper

A Case Comparison of Single-Image Photogrammetry Methods

1989-02-01
890737
Analytical reverse projection is introduced and is shown to offer an improvement in applicability and accuracy over other techniques of single-image photogrammetry, including plane-to-plane transformation and camera reverse-projection methods. A comparison of the methods is made on the basis of a single case of reconstructing missing tire tracks on a roadway intersection. Advantages and disadvantages of each method are discussed. THIS PAPER REVIEWS non-graphical techniques used to make measurements of features imaged in a single photograph. Two formulations of the plane-to-plane transformation method are re viewed, the camera reverse-projection technique is presented, and a third technique, called the analytical reverse-projection method, is introduced. Following a review of the various methods, including an indication of their advantages and disadvantages, each method is applied to the problem of relocating a set of tire tracks in an intersection.
Technical Paper

A Chronology of Forged Aluminum Wheel Development at Alcoa

1983-02-01
830018
In the late 1940’s Alcoa began marketing forged aluminum disc wheels for Class VII and VIII highway tractors, and in 1972 stylized passenger car wheels. This paper covers the evolution of some early pre-production designs to the present.
Technical Paper

A Cold Start and Pumpability Study of Fresh and Highly Sooted Engine Oils in 1999 Heavy Duty Diesel Emission Engines

2003-10-27
2003-01-3224
The new API CI-4 category defines oil quality suitable for 2002 EGR-equipped heavy duty diesel engines. Included in the category is the first used oil low temperature MRV (Mini-Rotary Viscosity) limit. Over the past 15 years heavy duty pumpability studies have been the focus of a number of studies but few have evaluated used engine oils, particularly at the high soot loadings expected in EGR-equipped engines. To gain a better understanding of rheological effect, Imperial Oil initiated fired pumpability tests of sooted and fresh oils. Three 1999 model year Class 8 heavy duty diesel trucks equipped with engines from three popular manufacturers were chosen for the study conducted in Imperial Oil's All-Weather Chassis Dynamometer. Fresh 15W-40's were compared to used 15W-40 oils taken from severe line-haul service where soot loadings were in the 6-7% range; limited testing was also conducted on a fresh 0W-40 formulation.
Technical Paper

A Combined Computational-Experimental Approach for Modelling of Coupled Vibro-Acoustic Problems

2013-05-13
2013-01-1997
Over the past 30 years, the computer-aided engineering (CAE) tools have been applied extensively in the automotive industry. In order to accelerate time-to-market while coping with legal limits that have become increasingly restrictive over the last decades, CAE has become an indispensable tool covering all major fields in a modern automotive product design process. However, when tackling complex real-life engineering problems, the computational models might become rather involved and thus less efficient. Therefore, the overall trend in the automotive industry is currently heading towards combined approaches, which allow the best of the both worlds, namely the experimental measurement and numerical simulation, to be merged into one integrated scheme. In this paper, the so-called patch transfer function (PTF) approach is adopted to solve coupled vibro-acoustic problems. In the PTF scheme, the interfaces between fluid and structure are discretised in terms of patches.
Technical Paper

A Comparative Analysis of High-Accuracy Black-Box and Grey-Box Models of MR-Dampers for Vehicles Control

2004-05-04
2004-01-2066
The topic of this paper is the identification of a high-precision model for Magneto-Rheological (MR) dampers. A semi-active MR-damper can be seen as a non-linear system, where the inputs are the stroke-velocity and the command current; the current is the control input which modulates at high-bandwidth the damping characteristic through the variation of a magnetic field. The output is the force delivered by the damper. Among the broad set of applications where MR-dampers can be used, this work mainly focuses on MR-dampers for the control of vehicle dynamics (trains, road vehicles, tractors, etc.). High-precision models of MR dampers can be designed using two different model classes: gray-box models (also called semi-physical models) and black-box models. Both approaches are considered in this work.
Technical Paper

A Comparative Analysis of WHR System in HD Engines Using Conventional Diesel Combustion and Partially-Premixed Combustion

2012-09-24
2012-01-1930
In the truck industry there is a continuous demand to increase the efficiency and to decrease the emissions. To acknowledge both these issues a waste heat recovery system (WHR) is combined with a partially premixed combustion (PPC) engine to deliver an efficient engine system. Over the past decades numerous attempts to increase the thermal efficiency of the diesel engine has been made. One such attempt is the PPC concept that has demonstrated potential for substantially increased thermal efficiency combined with much reduced emission levels. So far most work on increasing engine efficiency has been focused on improving the thermal efficiency of the engine while WHR, which has an excellent potential for another 1-5 % fuel consumption reduction, has not been researched that much yet. In this paper a WHR system using a Rankine cycle has been developed in a modeling environment using IPSEpro.
Technical Paper

A Comparative Review of Fuel Cell Vehicles (FCVs) and Hybrid Electric Vehicles (HEVs) Part II: Control Strategies, Power Train, Total Cost, Infrastructure, New Developments, and Manufacturing & Commercialization

2003-06-23
2003-01-2299
In this paper, a number of issues of concern in relation to hybrid electric vehicles (HEVs) and fuel cell vehicles (FCVs) are discussed and comparatively reviewed. Currently, almost all the activities in the development of new generation of vehicles are focused on FCVs and HEVs. However, there are still uncertainties as to which provides the maximum benefits in terms of performance, energy savings, impact on environment etc. In particular, potential control strategies for FCVs and HEVs will be discussed and compared. For FCVs, these include power-averaging control as well as control based on maximum conversion efficiency, among others. HEV control strategies include electrically peaking hybrid propulsion, and parameter optimization approaches such as battery SOC maximization, emissions minimization, and optimal power management.
Technical Paper

A Comparative Study Between Different Psychological Approaches During an ESA Space Simulation

1994-06-01
941358
The objectives are to compare different psychological methods used to assess the evolution of the interrelations inside the crew and the relationships between the crew and the outside in a sixty days isolation/confinement's simulation. After presenting each method, results are compared. The discussion try to point out if these methods are equivalent or if they are complementary. The specificity of each method is shown and conclusions try to associate some methods with specific scientific goals.
Technical Paper

A Comparative Study of Physical Layers of In-Vehicle Multiplexing Systems

1999-03-01
1999-01-1271
Today's vehicles use electronic control units to control engine/transmission, body and other amenities. These electronic control units are integrated into a computer network generally known as multiplexing system. There are a number of protocols, recommended practices available from SAE, ISO and other organizations for implementing the multiplexing system. This paper will provide an overview of various protocols, recommended practices available for in-vehicle networks. It provides a comparison of the physical layer of various protocols.
Technical Paper

A Comparative Study of Rollover Crashes Involving Passenger Cars With and Without Electronic Stability Control (ESC)

2011-04-12
2011-01-0951
The analysis presented here updates and expands previous research in which rollover critical events were classified based on a detailed review of about 500 police-reported single-vehicle rollover crashes of ESC-equipped vehicles. In order to compare the rollover performance of vehicles with and without ESC for the present study, an additional sample of 150 police reports on non-ESC passenger cars and 196 police reports on light vehicles with ESC in single-vehicle rollovers were obtained, and detailed coding of rollover scenarios was performed. The coding effort was undertaken by an engineering team and focused on critical events leading to rollovers (departure from road, loss of directional control, impact with an object, and departure from road with possible driver's input); driver factors (alcohol/drug involvement, speeding, inattention, distraction, fatigue, and overcorrection); and environmental factors.
Technical Paper

A Comparative Study of Turbulence Models in Axisymmetric Nozzle Flow

1995-05-01
951440
Two turbulence models have been studied to determine which of the models should be used in further Computational Fluid Dynamics (CFD) research. A zero-equation turbulence model, Baldwin-Lomax (B-L), is easy to use, requires no history of the flow, and requires little in the way of additional computations or additional computer memory space [1]. A two-equation k-ε model, Yang-Shih (Y-S), is more difficult to implement, does require flow history, and requires many more computations and much more computer space; however, it is potentially more accurate than the B-L model [2]. Using both Navier-Stokes (NS) and Parabolized Navier-Stokes (PNS) solvers, the two models and their codes were validated against the testbed of the Wright Laboratory (WL) Mach 12 wind tunnel nozzle.
Technical Paper

A Comparison between Different Moving Grid Techniques for the Analysis of the TCC Engine under Motored Conditions

2019-04-02
2019-01-0218
The accurate representation of Internal Combustion Engine (ICE) flows via CFD is an extremely complex task: it strongly depends on a combination of highly impacting factors, such as grid resolution (both local and global), choice of the turbulence model, numeric schemes and mesh motion technique. A well-founded choice must be made in order to avoid excessive computational cost and numerical difficulties arising from the combination of fine computational grids, high-order numeric schemes and geometrical complexity typical of ICEs. The paper focuses on the comparison between different mesh motion technologies, namely layer addition and removal, morphing/remapping and overset grids. Different grid strategies for a chosen mesh motion technology are also discussed. The performance of each mesh technology and grid strategy is evaluated in terms of accuracy and computational efficiency (stability, scalability, robustness).
Technical Paper

A Comparison of Componentization Constructs for Supporting Modularity in Simulink

2020-04-14
2020-01-1290
The Model-Based Development (MBD) paradigm is widely used for embedded controls development, with the MathWorks Simulink modelling environment being extensively used in the automotive industry. As production-scale Simulink models are typically large and complex, there exists a need to decompose them properly in order to facilitate their maintainability, understandability, and evolution. MathWorks recommends the use of three constructs for model “componentization” or decomposition: the Subsystem, Library, and Model Reference. However, a recently added construct introduced in Simulink R2014b, the Simulink Function, can also be used for this purpose, while also supporting information hiding due to the construct’s ability to be scoped and encapsulate data.
Technical Paper

A Comparison of Controller Designs for an Active, Electromagnetic, Offroad Vehicle Suspension System Traveling at High Speed

1998-02-23
980924
This paper discusses controller development for an active, off-road vehicle suspension system. A brief review of electronic filters and their characteristics is used to provide insight on the difficulties of designing a control algorithm for negotiating hilly and rough terrain at higher speeds. Two controller designs are presented. One was designed by pole placement and causes the suspension response to approximate a Type 1 Chebychev filter. The other was designed using constrained optimization. A comparison and discussion of simulation results leads to the conclusion that the suspension should be adaptively or predictively controlled for arbitrary terrain and velocity conditions.
Journal Article

A Comparison of Experimental and Modeled Velocity in Gasoline Direct-Injection Sprays with Plume Interaction and Collapse

2017-03-28
2017-01-0837
Modeling plume interaction and collapse for direct-injection gasoline sprays is important because of its impact on fuel-air mixing and engine performance. Nevertheless, the aerodynamic interaction between plumes and the complicated two-phase coupling of the evaporating spray has shown to be notoriously difficult to predict. With the availability of high-speed (100 kHz) Particle Image Velocimetry (PIV) experimental data, we compare velocity field predictions between plumes to observe the full temporal evolution leading up to plume merging and complete spray collapse. The target “Spray G” operating conditions of the Engine Combustion Network (ECN) is the focus of the work, including parametric variations in ambient gas temperature. We apply both LES and RANS spray models in different CFD platforms, outlining features of the spray that are most critical to model in order to predict the correct aerodynamics and fuel-air mixing.
Technical Paper

A Comparison of Gas Turbine Concepts Proposed for Automobiles

1980-02-01
800191
With the passage of the Automotive Propulsion Research and Development Act of 1978 (Public Law 95–238), the government has made funding available to supplement industry in long term-high risk Research and Development (R&D) on advanced automotive propulsion systems. The U.S. Department of Energy (DOE), which had a number of on-going programs in alternative automotive powertrains, has been chartered to carry out the intent of the Act. One of the programs sponsored by DOE has been in Advanced Gas Turbines (AGT) suitable for automobiles with high fuel economy, low exhaust gas emissions and the ability to operate on alternative fuels. This program is the outgrowth of government supported R&D in automotive gas turbines dating back to 1972. It is currently in the beginning phase of two major contracts awarded in late 1979.
Technical Paper

A Comparison of Seven Different Noise Identification Techniques

2003-05-05
2003-01-1690
Today's NVH engineers have at their fingertips a myriad of different noise source identification techniques available with which to locate noises. Unfortunately, with so many different techniques available, it is not always clear which technique is the best for a specific application. Should one use Sound Intensity? Or is Acoustic Holography a better tool? But if there are noises above 5kHz, which technique works then? And what is Beamforming? Would that work? With so many choices, it is required to know before the test which technique is the best choice. This paper will give an overview of 7 popular techniques to help the practicing NVH engineer decide which technique is the best for a specific application. A practical explanation along with a real life example will be given to help make clear where and how a technique can be used.
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