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Viewing 271 to 300 of 36625
1989-09-01
Technical Paper
891942
Mariusz Ziejewski, Joseph Stanislao, Sherman Goplen, Tiat Eng Wee
A new type of centrifugal pump which can be used for transportation of alternate fuels such as coal slurries was tested. Design and performance of the pump, and analysis of the fluid flow in the pump is presented. The unique internal flow pattern, which was determined using a high speed camera, results mainly from the recessed impeller design and the geometry of the blades. The qualitative and quantitative analysis of the flow profiles indicate the existence of suitable conditions for a decrease in the direct contact of the abrasive particles of the slurry with the interior surface of the pump which translates to longer maintenance-free performance. The test pump performance for slurries at higher concentrations compared well with the existing slurry pumps. The highest concentration used during the test was 60% by weight. At this level the maximum efficiency of the pump was 30%. The corresponding power required and the flow rate were 5.97 kW and 528 L/min, respectively.
1989-09-01
Technical Paper
891960
Michiaki Sasaki, Kiyokazu Yamamoto
Abstract This paper presents a swiring flow type jet pump which has been developed and in put into practical use in transferring fuel between sumps in saddle-shaped fuel tanks. The pump is driven by the force of excess fuel returning from the engine. The major structural features of the pump are described along with its performance. Various problems encountered in the process of developing the pump are discussed along with the technologies developed to resolve them. Particular attention is focused on the effects that the geometries if the nozzle, throat and swirling groove have on fuel transfer efficiency. The results of experiments carried out to analyze these correlations are also presented.
1989-09-01
Technical Paper
891948
Henrik Krabsen
Within recent years, the use of electric remote controlled proportional valves in the mobile market has increased dramatically. Manufacturers have realised that the use of electro-hydraulics opens up new design opportunities such as remote valve installations, precise fingertip control, electronic management of hydraulic machines, in fact an exciting new world. Engineers have new options and possibilities to meet the customers demands for higher productivity, less power consumption and an ergonomically improved working environment. Fig. 1 shows a representative selection of valves, joy stick controllers and electrical accessories for mobile equipment such as the backhoe described in this paper. The electrical activation system is indicative of the direction development is taking. More and more electronics for control, regulation, monitoring and automating hydraulic systems are being used.
1989-09-01
Technical Paper
891931
William C. Orthwein
Programs for personal computers or programmable calculators for the preliminary design of gears having external involute teeth with nonstandard proportions are described along with the formulas involved. They include the formulas necessary to produce an involute profile, a program to calculate the addendum radius for a given top land thickness and to solve a transcendental equation involved in that calculation, a program to calculate the contact ratio for two external gears in mesh, a formulation in terms of involute parameters of the Heywood-Cornell (modified Heywood) relation for tooth stress at the fillet, a program to evaluate this formulation, and a program to estimate the life of each of two gears in mesh as formulated at the NASA Lewis Research Center. These relations are applied to the design of a gear pair to provide a 3:1 speed ratio for pressure angles of 14.5°, 20°, and 25°.
1989-09-01
Technical Paper
891943
Robert G. Dubensky, Donald E. Jay, Ralph K. Salansky
The manufacturing analysis of molded plastic parts is described in detail. A PC based program is presented to analyze the material and capital cost. The program listing is included.
1989-09-01
Technical Paper
891937
Jim C. Fitch, Dan Dyer
Condition control is defined as the interactive processes of condition monitoring, condition analysis, and condition response. A model is presented which employs the use of an expert system to achieve real-time condition control of a hydraulic system. The approach focuses on adaptive “self-reference” learning and machine intelligence to monitor and analyze pre-degradation “incipient” failure conditions. Also presented are the corresponding realtime “reactive” condition responses, coupling system control with condition control.
1989-09-01
Technical Paper
891885
Thomas A. Esch, Gary R. Van Ee
A controllable trunk shaker was modeled as part of the design process for construction of a shaker that would not cause visible or nonvisible bark damage. Two different vibrational models were employed. A single degree-of-freedom model was used to optimize the size and shape of the shaker eccentric masses. A multiple degree-of-freedom model was developed to predict shaker behavior when shaking trees of various trunk diameters. Field tests conducted with the constructed shaker indicated qualitative agreement with the model was good. Quantitative agreement was also satisfactory, with peak-to-peak amplitudes within 30% of actual values.
1989-09-01
Technical Paper
891886
Richard J. Smith, Stan Lukowski, Liansuo Xie, Paul W. Claar
A kinematic model for studying the maneuverability of an off-road tractor/double-axle trailer combination has been formulated. The influence of steering inputs from the tractor and the trailer front axles on the system's maneuverability in terms of lateral displacement and rotational motion during the turning process is studied by conducting computer simulations using the LOTUS spreadsheet program. A lane-change problem is presented to demonstrate the computational procedure and to illustrate the application of the kinematic model.
1989-09-01
Technical Paper
891889
Scott A. Herbst
In an effort to improve the reliability of electronic control modules used to automate operation of trucks, a database was conceived to aid in the proper selection of electronic components. An accompanying application program provided a means of information exchange between the user and the database, while controlling (accessing, updating, and navigating through) the database.
1989-09-01
Technical Paper
891887
S. A. Lukowski, P. W. Claar, L. Xie
This paper discusses the computer simulation of a road-vehicle directional response to fixed-control steering inputs using a general purpose simulation language, ACSL. The equations of motion are derived to evaluate the vehicle directional behavior in terms of sideslip angle, yawing velocity gain, and path curvature gain. Computer simulations have been performed to examine the influence of tire lateral stiffnesses, load distribution on front and rear axles, and forward speed on vehicle directional response, in particular on the vehicle turning geometry.
1989-09-01
Technical Paper
891893
Mariusz Ziejewski, D. S. Gill
The application of a multiple polynomial regression procedure for optimization of design and performance parameters has been presented. To illustrate the statistical method, data from a laboratory test of an exhaust emission reduction device was used. There were four factor variables for which the response was constructed. Among the factor variables two were design parameters; the remaining two were the operating parameters. The selected response variables were CO, NO, and HC's. The assumptions for the analysis procedure are presented. Problems which could affect the validity of the statistical procedures for the design optimization are discussed. Experimental verification of the optimization results was performed. Overall agreement between the predicted level of pollutants reduction and measured values did not differ by more than ten percent.
1989-09-01
Technical Paper
891883
K. C. Tsao, Yong Xu
The nucleation and micro-explosion phenomenon of a water emulsified fuel droplet is re-examined theoretically and experimentally. The existence of micro-explosion is reaffirmed by recording the acoustic intensity during the explosion process. A theoretical model is developed to calculate the time required from nucleation to micro-explosion for a given surface heat flux. Both the theoretical and experimental results indicate that, in addition to the droplet internal superheat temperature, there exists a necessary condition for micro-explosion to occur. The necessary condition is that a minimum heat flux at the droplet surface he exceeded. This minimum surface heat flux is a function of droplet size, water fraction in parent fuel and the composition of parent fuels. The intensity of micro-explosion is greatly affected by the rate of heat transfer at droplet surface. All five fuels display a preferable range of water volume fractions for greater violent fragmentation.
1989-09-01
Technical Paper
891882
Mohamed N. Saeed, Mustafa M. Megahed, Medhat M. Sorour, Mohamed B. Madi
A general model, which uses general equations to determine the thermophysical properties of fuels in terms of temperature, molecular mess, critical constants and molecular structure, has been developed to describe the evaporation characteristics of multicomponent fuel droplets according to both the shell and ideal solution postulates. Upon applying this model to alcohol-dodecone mixtures, the feasibility of such mixtures for heterogeneous combustion systems has been assessed, and feasibility charts have been developed.
1989-09-01
Technical Paper
891888
Stephen H. Craney
In calendar year 1988, data was kept on the build of over one million electronic boards and assemblies. The results of this data gives strong evidence on where to receive optimal value for the dollars spent in the various areas of the electronic assembly process. Failure rates given should give good reference points for expected future programs and enable users to make decisions on process controls and vendor screening.
1989-09-01
Technical Paper
891884
E. H. Albright, P. W. Claar
A computer simulation model was developed to calculate the tractive performance of agricultural tractors with front and rear mounted three -point hitching arrangements. With a FORTRAN program, the performance parameters for the tractor were simulated and evaluated for four different tractor models. Two hitch positions were chosen for the sensitivity analysis with respect to static weight distribution. Two different traction prediction equations were evaluated.
1989-09-01
Technical Paper
891905
Metin Ozen
The behavior of a surface crack that is perpendicular to the contact surface was investigated by using the finite element method. The analysis was two-dimensional, plane strain, and linear elastic. The finite element model was a combination of 6-node triangular and 8-node isoparametric solid elements. A Hertzian pressure was applied at the contact surface. The contact pressure was moved incrementally on the surface to simulate rolling and sliding contacts.. Stress intensity factors were calculated as functions of the position of the Hertzian contact, coefficient of friction on the rolling/sliding surface, and the amount of residual stress in the subsurface. The results suggest Mode I type of growth under tensile residual stresses and Mode II type of growth under compressive residual stresses.
1989-09-01
Technical Paper
891915
Jimei Sun, Yu Dong, Yong Xu, K. C. Tsao
In cylinder gas motion of an open chamber diesel engine is modeled via a newly developed non-isotropic turbulent flow approach. The theoretical treatment is based on the turbulent kinetic energy-dissipation-random model of Reynolds stress (k - ε - R) which incorporates the non-isotropic fluctuating characteristics of gas movement during a compression stroke of a direct injection diesel engine. The validity of the model was compared to the experimental measurement obtained on an axisymmetric reentrant bowl chamber engine configuration. The experimental data fit much more closely to the established non-isotropic behavior in contrast to the traditional isotropic approach.
1989-09-01
Technical Paper
891895
Rodica A. Baranescu, Satish D. Desai, David A. Ginder
The paper describes a methodology for engine concept analysis by using cycle simulation coupled with optimization techniques (Taguchi Methods). The methodology was applied to the analysis of power output of a diesel engine as a function of five complex design parameters (“controllable factors”) and four uncontrollable parameters (“noise factors”). A thermodynamic cycle simulation program for a turbocharged diesel engine was used for power output computation. An L18 inner array with an L9 outer array were used for the Taguchi optimization. This methodology enables optimization early in the design stages and minimizes the needs for expensive and time consuming hardware testing, thus reducing product development time.
1989-09-01
Technical Paper
891897
Kevin L. Hoag, Susan Brasmer
The complementary use of flow visualization and computational fluid mechanics has been demonstrated for the development of cylinder head cooling jackets. Flow visualization was shown to allow the detailed characterization of fluid flow through the complex geometry of a cooling jacket. The use of high speed photography further aided in visualizing the details of the flow, and was used to quantify local fluid velocities. Computationally modeling portions of the cooling jacket allowed the extension of the flow visualization results to the fluid conditions of an operating engine. The computational model also provided an effective tool to assess the impact of modifications to the cooling jackets, without the complexity of modifying the flow visualization test rig for each iteration.
1989-09-01
Technical Paper
891899
Peter Reipert, Siegfried Mielke, Gunder Essig
Abstract Three different piston designs were fitted to a turbo-charged, intercooled diesel engine with cylinder diameter of 130 mm as follows: standard aluminum piston with casting gallery articulated piston with steel crown and aluminum skirt nodular cast iron piston with shrink fit ceramic section. The temperature distribution and thermal balance of the piston designs were calculated as a function of mean effective pressure, based on extensive temperature measurements and with the help of the Finite Element Method. The heat flowing into the piston affects the engine oil, the cylinder, the rings and the piston pin. The significantly varying heat flows are quoted as a function of mean pressure for each piston design. The heat balance of articulated pistons with and without sprayed on ceramic coatings and their thermal deformations are compared.
1989-09-01
Technical Paper
891997
Naotaka Hirami, Takamichi Teraoka, Yuji Mori, Hideki Kita, Masafumi Nakazawa
Demand for lighter and smaller automotive transmissions is accelerating the need to accurately predict the helical gear root stress. In an effort to identify the maximum root stress of a in-mesh tooth, the load distribution along the contact line is investigated with 3-dimensional finite element models. Resultant data from the FEM analysis was utilized to derive a simple formula that aims to serve the same purpose. This formula takes into consideration three new factors on stress compensation, effective facewidth and stress concentration in addition to the tooth form commonly associated in stress calculations.
1989-09-01
Technical Paper
891977
Akira Ohnuma, L. Daniel Metz
Four wheel steering (4WS) of passenger cars has become a topic of interest in recent vehicle dynamics literature. In the present work, a linear two-degree of freedom model (L2DF) has been used to examine controllability and stability aspects of various 4WS algorithms. Yaw rate r and lateral velocity v were used as model degrees of freedom, and as state feedback variables for the implementation of 4WS controllers of various types. With controllers developed using the L2DF model, investigations were performed into the performance of such controllers when implemented using a nonlinear three-degree of freedom model (N3DF) which included roll and the possibility of tire saturation. Desirable steady-state properties for v and r can be obtained using the robust controllers developed through the use of the L2DF model. Finally, the stability of the system is shown to depend upon tire cornering stiffness, and is examined both qualitatively and quantitatively.
1989-09-01
Technical Paper
891976
D. H. Robbins
This paper discusses four aspects of computer modeling of restraint system performance: Components of restraint systems (both vehicle and restraint hardware components) Analytical representations of the system including lumped mass occupant computer codes (CAL3D, MADYMO, etc.) as well as finite element codes (PISCES™, PAM-CRASH™) Design applications of restraint system computer models Relations between auto makers and restraint system suppliers. To begin the discussion, the physical parameters of vehicles and restraint systems that affect occupant protection are listed. The purpose is to illustrate the difficulty in separating vehicle components from restraint system components. This is followed by a review of the current software for occupant simulation. This is complemented with a discussion of current development of finite element and finite difference representations of airbag restraints and occupants.
1989-09-01
Technical Paper
891975
Molsey B. Shkoinikov, Dilip M. Bhaisod, Bruce Tzeng
An overview of engineering methods used in automotive crash simulation is presented. The use of the lumped-mass-spring method (LMSM) and of the finite element method (FEM) as applied to state-of-the-art structural crashworthiness simulations is outlined. The relative merits of these methods in crashworthiness analysis are discussed.
1989-09-01
Technical Paper
891966
John G. Cherng, Wen J. Wu
The fundamental theory and techniques used in developing a design tool for climatic control of an automotive vehicle are presented. Methods for simulating automobile heating as well as air conditioning components and the vehicle passenger compartment are outlined. The program structure and simulation results are also included.
1989-09-01
Technical Paper
891992
R. G. Dubensky
A statement of the need for an integrated Computer-Aided-Engineering plan for a global, automotive society is presented. The current level of domestic and of-shore activities are presented, along with future trends. A proposed plan is presented as a starting point for implementation.
1989-09-01
Technical Paper
891994
Takashi Kosugi, Tetsuya Seino
Recently it is becoming more necessary than ever to carry out performance prediction and factor analysis at the initial design by-computer aided engineering (CAE), in order to ensure the high performance, safety and reliability of motorcycles and also to shorten the lead time of product development. Finite element method (FEM) plays a crucial role in this respect. In particular, since the vibration characteristic is one of the most important evaluation items, the demand for accurate vibration prediction at the initial design has become much more intense. In recent years, vibration simulation methods have achieved remarkable progress, and especially the substructural synthesis method (SSM), combined with FEM, is used as an effective tool for the requirements.
1989-09-01
Technical Paper
891996
Ichiro Yamazaki, Takeshi Inoue
Abstract Reduction of interior noise is an important factor in vehicle design and many experimental and theoretical studies have been carried out to find effective noise reduction techniques. Previously, we developed a Structural-Acoustic Uncoupled Program, ACOUST3, as a technique for estimating low-frequency noise in the vehicle interior. In the present work, ACOUST3 has been extended to construct an acoustic coupling analysis system, ASCA, which is used to calculate low-frequency noise, such as boom noise. In order to calculate low-frequency noise accurately, it is necessary to represent the vibration characteristics of the trimmed body as closely as possible. To do this, we built a trimmed body model, incorporating 22 trim parts, based on vibration test results, and found that the calculated results obtained with the model correlated well with experimental data.
1989-09-01
Technical Paper
891991
James Bernard, Jay Shannan, Martin Vanderploeg
The high expense of vehicle testing leads to the desire to use analysis as much as possible to get an understanding of rollover resistance. There is no shortage of computer programs which claim to be capable of simulating rollover events. The challenge is in providing reasonable parameters for the simulation and in understanding the range of validity of the computed results. This paper presents various mathematical models which bear on rollover, starting with a very simple quasi-static model which requires knowledge of only a few measured vehicle parameters. It then deals with simulations of increasing complexity and increasing need for measurements to provide accurate and detailed input data. The paper closes with remarks on the relationship between simulation and vehicle testing for rollover resistance.
1989-09-01
Technical Paper
891995
Koji Yaginuma, Yoshio Yamada, Akitaka Kawata, Hiromi Mori
A conventional CAD system is aimed primarily at making the work of creating design drawings more efficient. There are limits, however, to further improvement of design efficiency and design quality with such a system. What is needed is a CAD system that allows design information of various kinds to he compiled for ready access and exchange among designers. To realize a system of this sort, first of all a means was devised of putting into standard format the design information that needs to be included in product design drawings, and of storing this information in a database. These standard drawings are then used in creation of new drawings, by means of an editing process. Moreover, this integrated design database system allows designers to exchange information related to the design work online, in the form of drawing elements.
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