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Technical Paper

External Corrosion Resistance of CuproBraze® Radiators

2001-05-14
2001-01-1718
New technology for the manufacturing of copper/brass heat exchangers has been developed and the first automotive radiators are already in operation in vehicles. This new technology is called CuproBraze®. One of the essential questions raised is the external corrosion resistance with reference to the present soldered copper/brass radiators and to the brazed aluminium radiators. Based on the results from electrochemical measurements and from four different types of accelerated corrosion tests, the external corrosion resistance of the CuproBraze® radiators is clearly better than that of the soldered copper/brass radiators and competitive with the brazed aluminum radiators, especially as regards marine atmosphere. Due to the relatively high strength of the CuproBraze® heat exchangers, down gauging of fins and tubes in some applications is attractive. High performance coatings can ensure long lifetime from corrosion point of view, even for thin gauge heat exchangers.
Technical Paper

Influence of Charge Dilution on the Dynamic Stage of Combustion in a Diesel Engine

2001-03-05
2001-01-0551
A study of the influence of dilution, attained by air excess, upon the dynamic stage of combustion - the nucleus of a work producing cycle - in a diesel engine, is reported as a sequel of SAE 2000-01-0203. While the latter has been restricted to variation in dilution obtained by bleeding air compressed by the supercharger, here the scope of engine tests was expanded by incorporating an additional stage of compression. Besides revealing the mechanism of the dynamic stage, the paper demonstrates that its effectiveness is a linear function of the air excess coefficient, irrespectively how it is attained.
Technical Paper

Automotive Electronics: Trends and Challenges

2000-11-01
2000-01-C047
The car as a self-contained microcosm is undergoing radical changes due to the advances of electronic technology. We need to rethink what a "car'' really is and the role of electronics in it. Electronics is now essential to control the movements of a car, of the chemical and electrical processes taking place in it, to entertain the passengers, to establish connectivity with the rest of the world, to ensure safety. What will an automobile manufacturer's core competence become in the next few years? Will electronics be the essential element in car manufacturing and design? We will address some of these issues and we will present some important developments in the area of system design that can strongly impact the way in which a car is designed.
Technical Paper

LES and RNG Turbulence Modeling in DI Diesel Engines

2003-03-03
2003-01-1069
The one-equation subgrid scale model for the Large Eddy Simulation (LES) turbulence model has been compared to the popular k-ε RNG turbulence model in very different sized direct injection diesel engines. The cylinder diameters of these engines range between 111 and 200 mm. This has been an initial attempt to study the effect of LES in diesel engines without any modification to the combustion model being used in its Reynolds-averaged Navier-Stokes (RANS) form. Despite some deficiencies in the current LES model being used, it already gave much more structured flow field with approximately the same kind of accuracy in the cylinder pressure predictions than the k-ε RNG turbulence model.
Technical Paper

Variable Dynamic Testbed Vehicle: Dynamics Analysis

1997-02-24
970560
The Variable Dynamic Testbed Vehicle (VDTV) concept has been proposed as a tool to evaluate collision avoidance systems and to perform driving-related human factors research. The goal of this study is to analytically investigate to what extent a VDTV with adjustable front and rear anti-roll bar stiffnesses, programmable damping rates, and four-wheel-steering can emulate the lateral dynamics of a broad range of passenger vehicles. Using a selected compact-sized automobile as a baseline, our study indicated this baseline vehicle can be controlled to emulate the lateral response characteristics (including the vehicle's understeer coefficient and the 90% lateral acceleration rise time in a J-turn maneuver) of a fleet of production vehicles, from low to high lateral acceleration conditions.
Technical Paper

Surface Acoustic Wave Microhygrometer

1997-07-01
972393
A microhygrometer has been developed at JPL's Microdevices Laboratory based on the principle of dewpoint/frostpoint detection. The surface acoustic wave device used in this instrument is approximately two orders of magnitude more sensitive to condensation than the optical sensor used in chilled-mirror hygrometers. In tests in the laboratory and on the NASA DC8, the SAW hygrometer has demonstrated more than an order of magnitude faster response than commercial chilled-mirror hygrometers, while showing comparable accuracy under steady-state conditions. Current development efforts are directed toward miniaturization and optimization of the microhygrometer electronics for flight validation experiments on a small radiosonde balloon.
Technical Paper

In-Process Tool Utilization Analysis Based Machining Simulation

1998-06-02
981870
The study aims at analyzing the tool utilization by using a real-time machining simulation and investigating the behavior of the parameters which affect the tool wear based on the results of the analysis. In this study, the method of calculation of parameters which are necessary to predict the tool wear by using Z-map based machining simulation is developed. Furthermore, the possibility of estimating the tool wear from the results of the simulation was also examined by performing the real cutting experiments.
Technical Paper

Critical Issues in Quantifying Hybrid Electric Vehicle Emissions and Fuel Consumption

1998-08-11
981902
Quantifying Hybrid Electric Vehicle (HEV) emissions and fuel consumption is a difficult problem for a number of different reasons: 1) HEVs can be configured in significantly different ways (e.g., series or parallel); 2) the Auxiliary Power Unit (APU) can consist of a wide variety of engines, fuel types, and sizes; and 3) the APU can be operated very differently depending on the energy management system strategy and the type of driving that is performed (e.g., city vs. highway driving). With the future increase of HEV penetration in the vehicle fleet, there is an important need for government agencies and manufacturers to determine HEV emissions and fuel consumption. In this paper, several critical issues associated with HEV emissions and fuel consumption are identified and analyzed, using a sophisticated set of HEV and emission simulation modeling tools.
Technical Paper

Model and Control of Heat Release in Engines

1996-02-01
960601
The concept of the paper stems from the premise that the process of “heat release” in engines involves in essence the evolution and deposition of exothermic energy generated by combustion-events that can be governed promptly by a feedback, adaptive micro-electronic control system. The key to its realization is the principle of DISC (Direct Injection Stratified Charge) engine, implemented by a multi-jet system. The background and the salient features of such a system, referred to as a CCE (Controlled Combustion Engine), have been described in a companion paper (SAE 951961). Presented here are fundamental aspects of the model of the exothermic process and the intrinsic properties of its control system.
Technical Paper

Meeting Both ZEV and PNGV Goals with a Hybrid Electric Vehicle - An Exploration

1996-08-01
961718
This paper is written to provide information on the fuel efficiency, emissions and energy cost of vehicles ranging from a pure electric (ZEV) to gasoline hybrid vehicles with electric range varying from 30 mi (50km) to 100 mi (160km). The Federal government s PNGV and CARB s ZEV have different goals, this paper explores some possibilities for hybrid-electric vehicle designs to meet both goals with existing technologies and batteries. The SAE/CARB testing procedures for determining energy and emission performance for EV and HEV and CARB s HEV ruling for ZEV credit are also critically evaluated. This paper intends to clarify some confusion over the comparison, discussion and design of electric- hybrid- and conventional- vehicles as well.
Technical Paper

All Wheel Independent Torque Control

1988-08-01
881135
A torque control policy for four-wheel drive road-going vehicles is developed, based on the use of a compact variable ratio unit (VRU) located at each wheel. Since the appropriate hardware is not yet available, a computer model is developed to examine what gear ratio range and frequency response might be required of the hardware to allow for improved performance and stability over current four-wheel drive systems. A comparison is then made to a front-wheel drive (FWD), rear-wheel drive (RWD) and four-wheel drive (4WD) to determine the effectiveness of the derived control policy.
Technical Paper

Emission Control Cost-Effectiveness of Alternative-Fuel Vehicles

1993-08-01
931841
Although various legislation and regulations have been adopted to promote the use of alternative-fuel vehicles for curbing urban air pollution problems, there is a lack of systematic comparisons of emission control cost-effectiveness among various alternative-fuel vehicle types. In this paper, life-cycle emission reductions and life-cycle costs were estimated for passenger cars fueled with methanol, ethanol, liquified petroleum gas, compressed natural gas, and electricity. Vehicle emission estimates included both exhaust and evaporative emissions for air pollutants of hydrocarbon, carbon monoxide. nitrogen oxides, and air-toxic pollutants of benzene, formaldehyde, 1,3-butadiene, and acetaldehyde. Vehicle life-cycle cost estimates accounted for vehicle purchase prices, vehicle life, fuel costs, and vehicle maintenance costs.
Technical Paper

Jet Plume Injection and Combustion

1992-02-01
920414
The concept of JPIC (Jet Plume Injection and Combustion) is introduced as a radical refinement of DISC (Direct Injection Stratified Charge). The system for its implementation consists of a fuel injector and a PJC (Pulsed Jet Combustion) generator (described in our previous papers) connected in series via a check valve. In operation, rich air-fuel mixture is admitted thereby first to a lean charge in the cylinder, forming a turbulent jet plume, and, thereupon, the process of combustion is executed using a pulsed jet of combustion products created upon ignition, by means of a conventional spark discharge, of the mixture remaining in the cavity of the PJC generator. Charge stratification thus obtained affects not only chemical composition, but also the scale and intensity of turbulence. The latter is, under such circumstances, associated with a significant amount of entrainment due to the large scale vortex structure of the turbulent plume.
Technical Paper

Technical Findings from Automobile Impact Studies

1957-01-01
570011
AN engineering-oriented summary of the more significant technical findings derived from 12 automobile collision experiments conducted at impact speeds between 7 and 55 mph is presented here. Use of both human subjects and anthropometric dummy subjects facilitated procurement of critically needed data on human engineering aspects of collision injury minimization. An evaluation is made of four conditions of motorist restraint in terms of the force system applied to the motorist. Deceleration patterns, frame deformations, automobile impact analyses, and similar engineering data are given for several impact conditions. The instrumentation techniques for the collection of data in automobile collisions are briefly presented.
Technical Paper

Automobile Head-On Collisions - - series II

1959-01-01
590032
AN ENGINEERING evaluation of six automobile head-on collision experiments is presented for impact speeds ranging from 21 to 52 mph. An analysis of the relative collision performances of unit-body and frame-type construction is made. Anthropometric dummy subjects facilitate determination of force systems for restrained and unrestrained motorists, their dynamic and kinetic responses to impact, and the causative factors associated with motorist injury production.* The systems of instrumentation which enabled a comprehensive analysis to be made from an event lasting only 0.25 sec are briefly presented.
Technical Paper

Vehicle Trajectories After Intersection Collision Impact

1970-02-01
700176
The postcollision motion starts immediately upon completion of a collision impact where the vehicles obtain new sets of velocities through an exchange of momentum. Similitude with model study and fullscale automobile experiments indicate that the post-collision trajectory is essentially a plane motion, governed by inertia and tire friction. Trajectories depend on many parameters (such as tire friction coefficient, front wheel steering angle, vehicle geometrics, and whether wheels are locked or free to rotate) but not on the vehicle weight. Theoretical computation of trajectories are compared with experiments.
Technical Paper

Combustion Temperature, Pressure, and Products at Chemical Equilibrium

1963-01-01
630085
For the computation of the equilibrium combustion temperature and pressure of hydrocarbon fuel in air, an original set of eighteen equations is enlarged by the energy and mass balance, and the procedure is applied to the cases of constant volume and of constant pressure combustion. Examples of engine combustion, including the effects of air-fuel ratio and the effect of water injection or exhaust gas recirculation, are treated; the results of computation are presented in graphs. The procedure of transformation and coding of the equation system for the solution on an electronic computer is described.
Technical Paper

Conjugate Heat Transfer in CI Engine CFD Simulations

2008-04-14
2008-01-0973
The development of new high power diesel engines is continually going for increased mean effective pressures and consequently increased thermal loads on combustion chamber walls close to the limits of endurance. Therefore accurate CFD simulation of conjugate heat transfer on the walls becomes a very important part of the development. In this study the heat transfer and temperature on piston surface was studied using conjugate heat transfer model along with a variety of near wall treatments for turbulence. New wall functions that account for variable density were implemented and tested against standard wall functions and against the hybrid near wall treatment readily available in a CFD software Star-CD.
Technical Paper

Particle Image Velocimetry Measurements of a Diesel Spray

2008-04-14
2008-01-0942
The current study was focused on flow field measurements of diesel sprays. The global fuel spray characteristics, such as spray penetration, have also been measured. Particle Image Velocimetry (PIV) was utilized for flow field measurements and the global spray characteristics were recorded with high-speed back light photographing. The flow field was scanned to get an idea of the compatibility of PIV technique applied to dense and high velocity sprays. It is well proven that the PIV technique can be utilized at areas of low number density of droplets, but the center of the spray is way beyond the ideal PIV measurement conditions. The depth at which accurate flow field information can be gathered was paid attention to.
Technical Paper

Diesel Spray Penetration and Velocity Measurements

2008-10-06
2008-01-2478
This study is presenting a comparative spray study of modern large bore medium speed diesel engine common rail injectors. One subject of paper is to focus on nozzles with same nominal flow rate, but different machining. The other subject is penetration velocity measurements, which have a new approach when trying to understand the early phase of transient spray. A new method to use velocimetry for spray tip penetration measurements is here introduced. The length where spray penetration velocity is changed is found. This length seems to have clear connection to volume fraction of droplets at gas. These measurements also give a tool to divide the development of spray into acceleration region and deceleration region, which is one approach to spray penetration. The measurements were performed with backlight imaging in pressurized injection test rig at non-evaporative conditions. Gas density and injection pressure were matched to normal diesel engine operational conditions.
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