Showing papers in "SAE transactions in 1986"

Effect of drop breakup on fuel sprays

Abstract: Recently developed computer models are being applied to calculate complex interactions between sprays and gas motions. The three-dimensional KIVA code was modified to address drop breakup and was used to study fuel sprays. The results show that drop breakup influences spray penetration, vaporization and mixing in high pressure sprays. The spray drop size is the outcome of a competition between drop breakup and drop coalescence phenomena, and the atomization details at the injector are lost during these size rearrangements. Drop breakup dominates in hollow-cone sprays because coalescence is minimized by the expanding spray geometry. The results imply that it may be possible to use a simple injector and still control spray drop size and vaporization if the flow details are modified so as to enhance drop breakup and coalescence.

Development and Use of a Computer Simulation of the Turbocompounded Diesel System for Engine Performance and Component Heat Transfer Studies

Abstract: Mise au point et utilisation d'une simulation sur ordinateur pour l'etude des performances et des transferts de chaleur d'un moteur diesel turbocompound

Computerized knock detection from engine pressure records

Abstract: Utilisation de l'ordinateur pour detecter le cliquetis d'un moteur a partir des enregistrements de la pression

Effects of combustion chamber geometry on diesel combustion

Abstract: Influence de la geometrie de la chambre de combustion sur la combustion dans un moteur diesel

Heat Transfer into Ceramic Combustion Chamber Wall of Internal Combustion Engines

Abstract: Transfert de chaleur a travers les parois en ceramique de la chambre de combustion d'un moteur a combustion interne

Interchangeability of Gaseous Fuels — The Importance of the Wobbe-Index

Abstract: Etude de l'influence des proprietes des melanges combustibles gazeux/air sur les caracteristiques de fonctionnement du moteur. L'utilisation de l'indice de Wobbe comme un critere de qualite du combustible gazeux montre qu'a indices egaux deux melanges de combustible gazeux auront les memes consequences sur le fractionnement d'un moteur

Engine Dynamics: Time-Based Versus Crank-Angle Based

Abstract: Controle de la dynamique des moteurs. Comparaison entre un systeme de regulation base sur le temps et un systeme base sur l'angle du vilebrequin

Evaluation of Vibration with Respect to Human Response

Abstract: Methods of quantifying vibration with respect to human response are fully defined. The procedures may be applied to all types of vibration: multiple-axis and multiple-input motions which are steady-state, random or transient. The procedures are based on experimental research and have been applied to predict the discomfort, annoyance, health risks, interference with activities and motion sickness associated with vibration measured in a wide range of environments. The general method involves the assessment of 12 axes of vibration (the 3 translational and 3 rotational axes on a seat surface, the 3 translational axes at the seat back and the 3 translational axes at the feet). The method may be simplified so as to include only those axes of interest in specific environments. A scale of approximate discomfort, an 'action level' guide to the prevention of health effects, magnitudes of vibration which may interfere with activities, and a means of predicting the probability of motion sickness are provided. In all cases the frequencies, axes, locations and durations of the motions responsible for adverse effects can be identified. The application of the procedures to evaluate measurements in vehicles, assess computer predictions of vehicle vibration and optimise seat dynamics is described.

Crush Energy in Accident Reconstruction

Abstract: Etude d'une methode de reconstitution des accidents a partir des deformations subies par le vehicule

Visualization of automotive catalytic converter internal flows

Abstract: Internal flow details of a prototype dual-bed monolith converter were determined in water-flow visualization tests run on a full-scale transparent acrylic model. Using steadily flowing water seeded with a small quantity of tracer particles, fluid motion within transparent sections of the flow model was deduced from particle pathlines illuminated with a thin plane of laser light. Flow in the inlet transition separated from the diffuser walls and impinged as a constant-diameter jet on the leading face of the first monolith. Velocity profiles from streak photographs showed that the level of flow maldistribution in the first monolith was a function of Reynolds number.

The effect of engine speed on the TDC flowfield in a motored reciprocating engine

Abstract: Measurements of three velocity components have been obtained by forward-scatter laser Doppler anemometry in the transparent cylinder of a modified production engine motored in the speed range 300-2000 rpm with a disc-type combustion chamber and a compression ratio of 7.4. The in-cylinder flow development has been examined in detail with and without induction swirl at an engine speed of 1000 rpm. In both cases turbulence was non-isotropic during compression with a tendency towards isotropy at TDC. The swirl velocities at TDC of compression scaled linearly with engine speed while the volume-averaged turbulence intensity varied more than linearly with engine speed for both induction system configurations, increasing from 0.45 to 0.6 times the mean piston speed in the absence of induction swirl and from 0.4 to 0.5 with induction swirl.

A correlation between engine oil rheology and oil film thickness in engine journal bearings. Discussion

Abstract: Correlation entre la rheologie des huiles de moteurs et l'epaisseur du film lubrifiant dans les paliers de moteurs

Preliminary turbulence length scale measurements in a motored IC engine

Abstract: A recently developed laser Doppler velocimetry system for making two-point spatial correlation measurements of velocity fluctuations has been applied to the turbulent flow field of an IC engine. Fluctuation integral length scales have been measured within the clearance volume of a ported, single cylinder engine with a disc-shaped chamber and a compression ratio of 8.0. The engine was motored at 600 rpm and the engine flow field had a swirl ratio at top dead center of approximately 4. These measurements were made at the center of the clearance height at three-quarters of the cylinder radius. The integral length scale was found to reach a minimum of approximately one-fifth of the clearance height near TDC. Comparison of the results obtained using this technique with the integral length scales measured in engines by others authors using different methods gives agreement to within a factor of two.

Detection of Flame Propagation During Knocking Combustion by Optical Fiber Diagnostics

Abstract: This paper presents results on the phenomenon of knocking (detonation) during combustion in a single-cylinder spark ignition engine. The investigation of knocking combustion was made possible by observing in-cylinder flame propagation with a measuring technique that used optical fibers coupled with photo-multipliers. The results indicate that knocking combustion appears to occur as a result of autoignition and/or acceleration of the flame front in the squish crevices. At high knock intensities, the flame front velocity can be supersonic. The occurrence of knock damage does not necessarily correspond with location of knock onset.

Combustion Chamber Insulation Effect on the Performance of a Low Heat Rejection Cummins V-903 Engine

Abstract: Influence de l'isolation de la chambre de combustion sur les performances d'un moteur a faible deperdition de chaleur (Cummins V 903)

High Purity Magnesium AM60 Alloy: The Critical Contaminant Limits and the Salt Water Corrosion Performance

Abstract: Des essais normalises de corrosion en brouillard salin ont ete realises sur des alliages AM60 de purete controlee afin de determiner les niveaux critiques des contaminants (fer, nickel, cuivre) en dessous desquels d'excellentes performances en corrosion peuvent etre obtenues

Evaporative emissions from gasolines and alcohol-containing gasolines with closely matched volatilities

Abstract: Alcohol-gasoline blends have attracted con siderable attention for a variety of reasons, including their higher evaporative emissions compared with gasolines. To better understand the reasons for higher evaporative emissions with blends and to determine if blends with similar volatility (closely matched Reid vapor pressure and distillation temperatures) to gasoline would have equivalent evaporative emissions, experimen tal and modelling studies were undertaken. Evaporative emissions with alcohol-gasoline blends were nearly equal to or slightly lower than corresponding emissions with gasolines of similar volatility characteristics. By measuring vapor generation in the SUED test, it was deter mined that the alcohol-gasoline blends generated less mass of vapors than the corresponding gaso lines. The mathematical model developed to pre dict the evaporative vapor losses from the fuel tanks showed that the lower vapor generation by the oxygenated fuels was due to their lower vapor pressures at the test temperatures and the lower molecular weights of the vapors generated by these fuels.

Development of Disc-Brake Design Method Using Computer Simulation of Heat Phenomena

Abstract: In order to develop a vehicle efficiently, the performance of individual parts must be accurately estimated in the design stages. However, conventional methods of design have relied upon empirical techniques, resulting in the prolongation of vehicular development. Therefore, with a view toward eliminating such delay in the course of vehicle development, a variety of design investigation techniques using computers were examined. A new technique has been created in the case of disc rotors by combining existing investigation methods with newly developed techniques. The purpose of this paper is to introduce a newly-developed design investigation system for the thermal characteristics of disc rotors which have hitherto been difficult to quantify. As the first step, the temperature phenomena of disc rotors were theoretically considered by analyzing experimental data, referring to many studies in this field. On the basis of these results, a computer simulation technique was developed which enables the transient temperature characteristics and thermal strength performance to be quantitatively estimated in actual running conditions. At present, part of this technique is in practical use as a disc-rotor design investigation system, yielding satisfactory results. In this study, the disc rotor for the model 300ZX vehicle was used.

A Compact, Comprehensive Model of Large Turbocharged, Two-Stroke Diesel Engines

Abstract: Modele mathematique complet et compact pour un grand moteur diesel deux temps avec suralimentation par turbocompresseur

A 2-D Flame Visualisation Technique Applied to the I.C. Engine

Abstract: A two dimensional flame front visualisation technique, based on Mie scattering from particles dispersed in the combusting mixture, has been developed. The technique was used in an I.C. engine simulator to study the freely propagating flame in premixed combustion. It is shown that flame front structures can be resolved for scales as low as 2x10/sup -4/ m. These scales were observed at 1500 RPM where velocity fluctuations are known to be on the order of 6 m/s. For lean propane combustion. peninsulas and pockets of unburned mixture are observed in the postflame regions at 600 RPM. Higher turbulence levels increase the global flame front area by creating flame front corrugations of various length scales. Evidence of flame front wrinkles having sizes comparable to previously reported flame thickness in engines suggests that I.C. engine models should take into account the interaction between the velocity field and the detailed structure of the diffusive-reactive flame front zone.

Direct Measurement of the Turbulent Burning Velocity in a Homogeneous-Charge Engine

Abstract: An experiment is described for the direct measurement of the turbulent burning velocity during premixed combustion in a spark ignition engine The gas velocity is measured using a high data rate laser Doppler velocimeter system that resolves the unburned gas motion on an individual cycle basis The ensemble-averaged flame speed is determined from ionization probe measurements of the time of flame arrival at discrete positions along the path of flame propagation The difference between the cycle-resolved unburned gas velocity and the ensemble-averaged flame speed gives a direct measurement of the turbulent burning velocity that is unbiased by cycle variations in the combustion rate

Electrostatic Collection of Diesel Particles

Abstract: Utilisation des proprietes electrostatiques pour capter les particules emises par un moteur diesel

Testing a third derivative knock indicator on a production engine

Abstract: In a previous paper, a knock indicator based on the third derivative of the cylinder pressure trace has been developed. This knock indicator measures the rate at which pressure trace curvature changes from positive to negative during the knock peak. Since it is dealing only with the general shape of the pressure trace, it gives a measurement of combustion severity based on low frequency data such as is commonly used for engine cycle analysis. This low frequency sampling makes it useful for adding knock analysis to existing engine analysis programs without changes of equipment or significant increases in computational effort. It may also make it useful for future on-board engine controls using limited frequency response or heavily filtered pressure transducers. Results of using this knock indicator as a diagnostic tool on a multi-cylinder engine with a spark plug-mounted transducer are presented. It is shown that the third derivative knock indicator is a consistent pressure record knock diagnostic comparable with other suggested knock measurement methods, particularly considering the problems encountered with pressure trace distortion and resonance caused by a spark plug-mounted transducer.

Phenomenological diesel combustion model including smoke and NO emission

Abstract: An existing phenomenological model for combustion in quiescent and swirl assisted direct injection diesel engines developed by the authors has been extended to incorporate sub-models for exhaust smoke and nitrogen oxide emissions, based on published mechanisms for the formation of these two pollutants. Prediction of exhaust smoke and NO emission over a range of engine operating conditions including the effects of exhaust gas recirculation, has been undertaken for two quiescent and one swirl assisted engine. The predictions show well the general trend in emissions behaviour when compared with experiment, giving the possibility of using the model (with some calibration) for parametric studies.

Injector Deposits — The Tip of Intake System Deposit Problems

Abstract: A comprehensive program encompassing laboratory engine, laboratory vehicle, and taxi fleet tests was undertaken to evaluate fuel variables and induction system deposits in modern spark-ignition engines. The widespread fuel injector deposit problem was the primary focus. Injector and vehicle design, driving cycle, and fuel composition were found to be major contributing factors to injector deposition. Commercial gasoline additives capable of preventing and removing injector deposits were also identified. Some of these additives control intake valve and port deposits as well, while others actually contribute to valve and port deposits.