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Technical Paper

byteflight~A new protocol for safety-critical applications

2000-06-12
2000-05-0220
The permanently increasing number of convenience and safety functions leads to higher complexity of in-car electronics and the rapidly growing amount of sensors, actuators and electronic control units places higher demands on high- speed data communication protocols. Safety-critical systems need deterministic protocols with fault-tolerant behavior. The need for on-board diagnosis calls for flexible use of bandwidth and an ever-increasing number of functions necessitates a flexible means of extending the system. None of the communication solutions available on the market until now (like CAN or TTP) have been able to fulfill all these demands. To solve these problems, BMW together with several semiconductor companies has developed a new protocol for safety-critical applications in automotive vehicles.
Technical Paper

basic design of Turbochargers for diesel engines

1960-01-01
600007
ALTHOUGH turbocharging of low-speed diesel engines has been used world-wide for a long time, it is only during recent years that it has been applied to high-speed diesels. This is the result of considerable engineering efforts from both the turbocharger and the diesel side that were put into the turbocharger, which appears to be a so utterly simple device. This paper de­scribes some of these engineering efforts. The basic design characteristics are developed with the point of view in mind that the turbo­charger has become much more than just an ad­ditional accessory. It is a vital component of the basic engine itself, contributing actively to the advancement of this prime mover. The basic de­sign characteristics center heavily around aero­dynamical and thermodynamical performance cri­teria which are so important in any advanced high-speed turbomachine.
Technical Paper

and Repeatability of Transient Heat Release Analysis for Heavy Duty Diesel Engines

2009-04-20
2009-01-1125
Reduced emissions, improved fuel economy, and improved performance are a priority for manufacturers of internal combustion engines. However, these three goals are normally interrelated and difficult to optimize simultaneously. Studying the experimental heat release provides a useful tool for combustion optimization. Heavy-duty diesel engines are inherently transient, even during steady state operation engine controls can vary due to exhaust gas recirculation (EGR) or aftertreatment requirements. This paper examines the heat release and the derived combustion characteristics during steady state and transient operation for a 1992 DDC series 60 engine and a 2004 Cummins ISM 370 engine. In-cylinder pressure was collected during repeat steady state SET and the heavy-duty transient FTP test cycles.
Technical Paper

an evaluation of AFTERCOOLING in Turbocharged Diesel Engine Performance

1959-01-01
590049
AFTERCOOLING, coupled with higher pressure turbocharging can increase vehicle engine output. The author thinks that it is possible to anticipate diesel engines being run with compressors supplying air at pressure ratios higher than 2/1. Density ratio is the most important consideration in increasing pressure ratio, since the engine's output is dependent upon weight rather than volume of air supplied. Because the density of the compressed air is dependent upon its temperature at any pressure level, cooling the air after compression results in density increases. This paper describes various methods of after-cooling which increase engine output and fuel economy.
Technical Paper

a universal means for Rating Diesel Engines for Deposits and Wear

1960-01-01
600066
THE NEW CRC Diesel Engine Rating Manual is intended to furnish a universal language for identification of diesel-engine deposits and wear. Diesel-engine pistons are evaluated for lacquer deposits by utilizing an area demerit basis and color gradations of brown and gray from clean to black. In studying various means for evaluating thickness and texture of deposit in oil systems, it was decided that the scratch gage developed by the CRC Engine Deposit Rating Panel of the CRC-Motor Engine Varnish and Sludge Group was suitable for diesel engines. A procedure for establishing a volume factor which furnishes a weighted interpretation of the deposit was created.*
Technical Paper

Zone of Influence of Porous Suction Tubes in Condensing Heat Exchanger for Space Systems

2008-06-29
2008-01-2075
A “next generation” condensing heat exchanger for space systems has to satisfy demanding operational requirements under variable thermal and moisture loads and reduced gravity conditions. Mathematical models described here are used to investigate transient behavior of wetting and de-wetting dynamics in the binary porous system of porous tubes and porous cold plate. The model is based on the Richard's equation simplified for the zero-gravity conditions. The half-saturation distance or the zone of influence of the porous annular suction tubes on the cold-plate porous material will be in the range of 1 to 10 cm for the time scales ranging from 100 to 10,000 seconds and moisture diffusivity in the range of D = 10-4 to 10-6 m2/s.
Technical Paper

Zirconia Based Ceramic, In-Cylinder Coatings and Aftertreatment Oxidation Catalysts for Reduction of Emissions from Heavy Duty Diesel Engines

1997-02-24
970469
Diesel engines are coming under stricter requirements to reduce emissions. particularly those of particulates and nitrogen oxides (NOx). Recently, the U. S. EPA put into place staged requirements for heavy duty diesel engines in urban bus applications which are aimed at ultimately bringing pre-1994 engines into particulate emissions compliance with 1994 heavy duty on-road truck standards (0. 1 g/bhp-hr TPM). This reflects the need to control emissions in crowded urban environments. Zirconia based ceramic combustion management coatings, although originally developed for adiabatic or low heat rejection engines to boost thermal efficiency, have also been shown to contribute to the reduction in diesel emissions. Heavy duty transient testing of rebuilt 2-stroke MUI diesel bus engines equipped with stabilized zirconia based coatings applied by thermal spray process have shown significant reduction in exhaust opacity relative to a baseline, uncoated engine.
Technical Paper

Zero-Offset in Transducer Output

2005-05-16
2005-01-2555
Zero-offset in transducer output during airbag noise testing is often observed, but mostly ignored due to the lack of understanding of its causes and implications. In the field of high-g acceleration measurement, this phenomenon is well documented, and is referred to as zeroshift. Zero-offset occurs when a component in the measurement chain is exposed to some unexpected inputs which the component has not been designed to handle. These unexpected inputs can be mechanical, electrical, or optical. How the transducer reacts to such inputs and the amount of zero-offset produced depends on the sensing mechanism, material used, and the design of the component itself. This paper explores the causes of zero-offset from a general perspective, covering the entire measurement chain. Although much of the information and discussions are based on data obtained from acceleration measurement systems, the findings are applicable to other transducer types, such as pressure and acoustic measurements.
Journal Article

Zero-Dimensional Simulation of Diesel Engine Combustion and Emissions Based on CMC Model and Skeletal Reaction Mechanism

2011-04-12
2011-01-0845
A zero-dimensional code is developed to simulate turbulent spray combustion and NOx and soot emission in direct injection diesel engines. The code consists of two major parts; mixing calculation for the probability density function (PDF) based on the multi-zone model by Hiroyasu et al., (1983) and the flame structure by the conditional moment closure (CMC) model (Klimenko & Bilger, 1999). The skeletal mechanism of n-heptane is employed with the elementary reaction steps for heat release and the NOx chemistry in GRI 3.0. The spray model accounts for evaporation and mixing based on momentum balance of the spray zones, while the CMC model incorporates the conditional flame structures with one fuel group or flame structure for each injection. The spatially integrated density-weighted PDF, F(η), is defined to represent inhomogeneous mixture distribution in the cylinder. The one-equation soot model is employed for prediction of the soot emission.
Journal Article

Zero-Dimensional Modeling of Combustion and Heat Release Rate in DI Diesel Engines

2012-04-16
2012-01-1065
Zero-dimensional heat release rate models have the advantage of being both easy to handle and computationally efficient. In addition, they are capable of predicting the effects of important engine parameters on the combustion process. In this study, a zero-dimensional combustion model based on physical and chemical sub-models for local processes like injection, spray formation, ignition and combustion is presented. In terms of injection simulation, the presented model accounts for a phenomenological nozzle flow model considering the nozzle passage inlet configuration and an approach for modeling the characteristics of the Diesel spray and consequently the mixing process. A formulation for modeling the effects of intake swirl flow pattern, squish flow and injection characteristics on the in-cylinder turbulent kinetic energy is presented and compared with the CFD simulation results.
Technical Paper

Zero-Dimensional Heat Release Modeling Framework for Gasoline Compression-Ignition Engines with Multiple Injection Events

2019-09-09
2019-24-0083
A zero-dimensional heat release model was developed for compression ignition engines. This type of model can be utilized for parametric studies, off-line optimization to reduce experimental efforts as well as model-based control strategies. In this particular case, the combustion model, in a simpler form, will be used in future efforts to control the combustion in compression ignition engines operating on gasoline-like fuels. To allow for a realistic representation of the in-cylinder combustion process, a spray model has been employed to allow for the quantification of fuel distribution as well as turbulent kinetic energy within the injection spray. The combustion model framework is capable of reflecting premixed as well as mixing controlled combustion. Fuel is assigned to various combustion events based on the air-fuel mixture within the spray.
Technical Paper

Z-type Schlieren Setup and its Application to High-Speed Imaging of Gasoline Sprays

2011-08-30
2011-01-1981
Schlieren and shadowgraph imaging have been used for many years to identify refractive index gradients in various applications. For evaporating fuel sprays, these techniques can differentiate the boundary between spray regions and background ambient gases. Valuable information such as the penetration rate, spreading angle, spray structure, and spray pattern can be obtained using schlieren diagnostics. In this study, we present details of a z-type schlieren system setup and its application to port-fuel-injection gasoline sprays. The schlieren high-speed movies were used to obtain time histories of the spray penetration and spreading angle. Later, these global parameters were compared to specifications provided by the injector manufacturer. Also, diagnostic parameters such as the proportion of light cut-off at the focal point and the orientation of knife-edge (schlieren-stop) used to achieve the cut-off were examined.
Technical Paper

You-Are-Here Maps for International Space Station: Approach and Guidelines

2004-07-19
2004-01-2584
Guidelines for designing you-are-here (YAH) maps aboard International Space Station (ISS) are proposed, based on results from previous 3D spatial navigation studies conducted by our research group and colleagues. This paper reviews terrestrial YAH maps, the common errors associated with them, and how to appropriately implement what is known from terrestrial to micro-gravity YAH maps. We conclude with a creative example of an ISS YAH map that utilizes given guidelines and information visualization techniques.
Technical Paper

Yield Mapping with Digital Aerial Color Infrared (CIR) Images

1999-09-14
1999-01-2847
Yield potential was predicted and mapped for three corn fields in Central Illinois, using digital aerial color infrared images. Three methods, namely statistical (regression) modeling, genetic algorithm optimization and artificial neural networks, were used for developing yield models. Two image resolutions of 3 and 6 m/pixel were used for modeling. All the models were trained using July 31 image and tested using images from July 2 and August 31, all from 1998. Among the three models, artificial neural networks gave best performance, with a prediction error less than 30%. The statistical model resulted in prediction errors in the range of 23 to 54%. The lower resolution images resulted in better prediction accuracy compared to resolutions higher than or equal to the yield resolution. Images after pollination resulted in better accuracy compared to images before pollination.
Technical Paper

Yield Mapping of Soybeans and Corn Using GPS

1995-09-01
952112
Data obtained when harvesting with a combine equipped with a yield monitor were used to develop yield maps. A prototype yield monitor was developed that uses a combination of light emitters and receivers mounted in a rectangular frame. The monitor was mounted in the combine in the top of the clean grain elevator. As grain flows through the monitor, a voltage change proportional to light reduction was recorded. This voltage was then correlated to grain flow rate. At the same time, site-specific location was recorded using the global positioning satellites (GPS) system. The location data, yield monitor output, cutting width, and combine forward speed were stored in a spreadsheet format. The data were then used to prepare the yield maps.
Technical Paper

Xenon Light for Main and Dipped Beam

1998-02-23
980005
Xenon (HID) technology is one of the mile-stones in developing process of car lighting. The first step was to combine this technology with free-form reflector technology. The result was a high performance dipped beam beam-pattern with three times more light output compared to a halogen system. The next step of improvement is “Bi-Xenon”. It makes sense to use the enormous light output of a Xenon light source for two light functions (Main beam and dipped beam) in a single pocket headlamp system. This leads to new lighting performance and design freedom in headlamp technology. In this paper the technological aspects of system realization will be described. New solutions in lighting strategy including modern actuators which handle optical elements to switch between two light functions had to be found.
Technical Paper

XMM-NEWTON Thermal Design and In-orbit Performance

2000-07-10
2000-01-2372
The XMM-NEWTON satellite is the ESA X-ray spaceborne observatory covering the soft X-ray portion of the electromagnetic spectrum. XMM-NEWTON has been put in orbit on December, 10th 1999 by an Ariane 5 single launch. The spacecraft has a conventional thermal design that takes full advantage of the stable environment provided by its high altitude/long period orbit and by the limited variation of solar attitude angles in order to provide a stable platform for the telescope system. The precise geometry and alignment of the telescope system impose strict temperature requirements so that not only temperature gradients have to be kept small but also, and more importantly, time-variations of the gradients have to be minimised. In the paper, the thermal behaviour of the spacecraft as verified by its thermal test programme is compared with the early in-orbit temperature measurements.
Journal Article

X-ray Imaging of Cavitation in Diesel Injectors

2014-04-01
2014-01-1404
Cavitation plays a significant role in high pressure diesel injectors. However, cavitation is difficult to measure under realistic conditions. X-ray phase contrast imaging has been used in the past to study the internal geometry of fuel injectors and the structure of diesel sprays. In this paper we extend the technique to make in-situ measurements of cavitation inside unmodified diesel injectors at pressures of up to 1200 bar through the steel nozzle wall. A cerium contrast agent was added to a diesel surrogate, and the changes in x-ray intensity caused by changes in the fluid density due to cavitation were measured. Without the need to modify the injector for optical access, realistic injection and ambient pressures can be obtained and the effects of realistic nozzle geometries can be investigated. A range of single and multi-hole injectors were studied, both sharp-edged and hydro-ground. Cavitation was observed to increase with higher rail pressures.
Technical Paper

X-Ray Computed Tomography for Verification of Rivet Installation Assessment Techniques

1998-09-15
982140
High quality rivet installation is of critical importance to the aerospace industry, and the existence of gaps between the rivet head and the countersink is undesirable. Detection of gaps traditionally involves sectioning through rivet joints. Two concerns exist for this method of evaluation: it provides data only from the sectioned plane, and it has potential to alter the gaps. X-ray computed tomography (CT) was used to validate the effectiveness of the tradition sectioning method. It was revealed that the sectioning process generally increased the size of gaps. CT images also revealed that the gaps are not necessarily uniform around the rivet.
Article

X marks the spot

2018-03-22
LiquidPiston Inc. has developed a new engine that can run on multiple fuels, including diesel, jet fuel, and gasoline. This platform uses an optimized thermodynamic cycle and a new rotary engine architecture and could increases flight endurance over conventional UAV engines by greater than 50%.
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