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Technical Paper

Optimization of the Diesel Engine Injection Nozzle

1993-09-01
932467
The paper deals with the existing Diesel nozzles optimisation of the conventional injection system pump - high pressure pipe - nozzle. The aim of the optimisation is to increase the injection rate of the nozzle by 9 %, lower the fuel consumption and reduce the emissions of the engine. Existing and optimized nozzles should feature the same inlet pressure, i.e. the same load on the pump allowing that the same pump may be used also for the redesigned nozzle. Redesigned was the tip of the nozzle. The nozzle was optimized by computer simulation. The prototype of the redesigned nozzle was then tested on the test stand and in the four - stroke air - cooled engine according to the 13-mode ECE R49 cycle. Explained is also the influence of fuel injection parameters on engine performance and emission. All test results are presented in the paper.
Technical Paper

“Flower Power” Tractor Fuel Testing Program 1981-1987

1993-09-01
932476
Field tests for a variety of fuels on different tractor engines were carried out during the summers of 1981 through 1986. Fuels tested included alkali refined and winterized sunflower oil blended with diesel fuel, crude degummed sunflower oil blended with diesel fuel, high oleic safflower oil blended with diesel fuel, methylester of sunflower oil, or soybean oil. Blends of either 25% vegetable oil and 75% diesel fuel or 50% vegetable oil and 50% diesel fuel were used. Methylesters were not blended with diesel fuel. The manufacturers that participated in the project were John Deere, J.I. Case and Allis Chalmers. The project indicated that farm diesel tractors can be operated on any of the fuels that were tested. Care should be taken, however, since some signs of premature engine problems were observed. In general, continued use of these fuels cannot be recommended at this time.
Technical Paper

Increasing Fatigue Strength in Gray Iron Castings

1993-09-01
932497
A study was initiated to determine how to increase the fatigue strength of gray iron cylinder blocks. The approach was to determine what combination of metallurgical properties and foundry processes would yield the highest fatigue strength while maintaining the castability necessary for these complex castings. This study, unlike much of the literature available on fatigue strength in gray iron, was conducted using hundreds of castings and thousands of test bars. A baseline data base was established. This information was used to determine which factors would be most likely to effect the fatigue strength. An experiment was designed to determine how the foundry processes and the metallurgical factors interacted with more than twenty-five response variables.
Technical Paper

Power Cylinder Design Variables and Their Effects on Piston Combustion Bowl Edge Stresses

1993-09-01
932491
During engine durability testing of a large diesel engine, several pistons were found to have experienced fatigue cracks along the combustion bowl edge directly over the pin bores. In order to determine the optimum design solution to this piston combustion bowl edge cracking problem, the performance of several power cylinder assemblies have been investigated to determine their effects on piston combustion bowl edge stresses. The power cylinder design variables examined in this analysis were piston skirt section thickness, piston compression height, pin inner and outer diameters and connecting rod end designs (Tee-Pee vs. straight). A finite element analysis of each power cylinder assembly was performed to ascertain the stresses existing on the piston combustion bowl edge. This finite element analysis found combustion bowl edge stresses from the thermal expansion effects only loading as well as those from the combined thermal expansion and combustion pressure loading.
Technical Paper

The Analysis of Diesel Engine Turbocharger Vibration Using Time Synchronous Averaging

1993-09-01
932500
Emergency Diesel Generators are used in the nuclear industry for stationary stand-by power in order to safely shut down a reactor unit in the event of loss of off site power. Therefore, a high diesel engine reliability and availability must be maintained. Engine turbochargers often experience operating failures resulting in extended down time and costly repairs. Improved turbocharger vibration testing using time synchronous averaging is one method for evaluating the operating condition of a turbocharger. Typical vibration collection methods result in the turbocharger vibration being masked by the high background noise associated with the reciprocating nature of the engine. Time synchronous averaging reduces the background noise and allows accurate measurement of the 1x RPM component and harmonics of the turbocharger. Trends of the turbocharger vibration may then be established for diagnostic purposes, giving the analyst another tool for improving engine reliability and availability.
Technical Paper

A FEM Thermal Analysis on a Novel Designed Air-Gap Insulated Piston

1993-09-01
932490
A novel design of an air-gap insulated piston has been proposed which is expected to give a longer life compared to the past designs and lower heat transfer there by increasing its crown temperature. Also it is light weight. The basic design of the piston, where the crown is separated from the body of the piston through a thick composite gasket. The crown and the piston base are fitted together by an interference fitting and locked by oval shaped rivets. A steady state two dimensional thermal analysis is done on the piston for the following five cases using FEM: Aluminum piston single piece as reference, aluminum crown with thick composite gasket and air-gap with aluminum base, composite crown and air-gap with aluminum base, all composite piston without air-gap and all composite with air-gap. Constant temperatures are assumed at gas, liner and oil boundaries of the piston. Also the film coefficients on the piston boundaries are kept constant for all the cases.
Technical Paper

The Influence of Oxidation Catalysts on NO2 in Diesel Exhaust

1993-09-01
932494
In underground noncoal mines the emission of nitrogen dioxide (NO2) in the exhaust of a diesel engine is more important than the emission of nitrogen oxide (NO) because of the much lower permissible exposure limit for NO2. Consequently, the tendency of aftertreatment devices such as oxidation catalytic converters (OCCs) to oxidize NO to NO2 is counterproductive. The U.S. Bureau of Mines (USBM) is investigating the effects of OCCs upon NO2 emission by using a Fourier Transform Infrared (FTIR) exhaust gas analyzer to compare the concentration of NO2 in diesel exhaust upstream and downstream of the OCC. We find that some OCCs increase the concentration of NO2 much more than others, and that over some temperature ranges the aftertreatment results in an apparent decrease in NO2 concentration.
Technical Paper

NVH Optimization of a 16-Cylinder Diesel Engine

1993-09-01
932492
In the early design stage a 16-cylinder V-engine is optimized with respect to its vibrational and acoustic behavior. The objectives of the development are: (1) to minimize vibrations of the crankcase with special focus on the structure-borne noise transmission via the engine mounts, and (2) in this context, to identify the appropriate locations for the engine mounts. The NVH behavior of the engine structure is simulated using the Finite Element Method (FEM). The dynamic FE-model of the engine is excited via synthesized cylinder pressure force spectra. The corresponding vibrations of the sound emitting surface are calculated, thereby revealing structural weaknesses. By calculation of the crankcase modal vibrations, the noise relevant modes are identified. Based on these results the influence of structural modifications on the NVH behavior is predicted.
Technical Paper

IVHS Transit Applications in Texas

1993-08-01
931849
A variety of intelligent vehicle-highway systems (IVHS) or advanced technologies are currently being examined as one approach to improving the effectiveness and efficiency of the transportation system. Many of these technologies are appropriate for use with public transportation systems. The use of a wide range of IVHS technologies may result in the improved delivery of transit services, enhanced customer information, and improved management capabilities Currently, transit systems in Texas and throughout the country are considering and implementing a variety of advanced technologies. This paper provides an overview of the application of IVHS technologies to public transit and describes some of the specific projects being planned and implemented in Texas.
Technical Paper

Designing Energy Absorbing Steering Wheels Through Finite Element Impact Simulation

1993-08-01
931844
Light metal alloys based on magnesium and aluminum are increasingly being pursued for various vehicle interior applications because of distinct advantages such as weight savings and potential parts consolidation. One such application of light metal alloys is the steering wheel, which is an important component of a safety system that is comprised of the driver-side airbag, steering wheel, the steering column and its attachment bracketry to the instrument panel and the vehicle body structure. For the airbag to function effectively as a restraint during a frontal crash, the steering wheel has to provide adequate support. In addition to the steering column which is designed to absorb energy, the wheel can also function as an energy absorber if so designed. One way of achieving this energy absorption is through plastic deformation of the wheel. Adverse material characteristics, however, make the energy absorbing steering wheel design, using light metal alloys, a sizeable challenge.
Technical Paper

Design, Development, Testing and Evaluation of Energy Absorbing Bumpers

1993-08-01
931843
At present most of the Indian vehicles are fitted with rigidly mounted bumpers without energy absorbing devices. An alternative to the rigidly mounted bumper is considered by designing and developing various energy absorbing devices and energy attenuators such as elastomers in various shapes and sizes, the collapsible, sheet metal fenders, metal flat springs and the ‘U’ type energy attenuator. The various factors such as aerodynamics, aesthetic, easy removal and mounting of the bumpers were also considered while designing and fabrication of the bumpers. The sheet metal and Fibre Reinforced Plastic (FRP) bumpers are designed and fabricated in four different types with various combinations of elastomers, energy absorbing devices and attenuators. A major emphasis is given on low cost fabrication of three dimensional bumper shell, dies, moulds, collapsible and energy absorbing device.
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

Vehicle Restitution Response in Low Velocity Collisions

1993-08-01
931842
The restitution or rebound that occurs as the final phase of a vehicle-to-vehicle collision is quantified by the coefficient of restitution, which is the ratio of the closing velocity to the post-impact separating velocity of the two colliding vehicles. The coefficient of restitution of medium and high velocity collisions is low, [approximately 0.1] since these collisions are quite inelastic, whereas collisions at extremely low velocities are relatively elastic with the coefficient of restitution theoretically approaching 1.0. However, the actual collision restitution magnitude in the low velocity range has not been adequately established. A series of vehicle-to-vehicle and vehicle-to-barrier collisions resulting in velocity changes in the 2 to 5 miles per hour range was conducted in which vehicles with various bumper configurations [factory standard equipment] were utilized to study the coefficient of restitution at low closing velocities.
Technical Paper

Overview of IVHS in the Texas Department of Transportation

1993-08-01
931848
In this paper is a discussion of Texas Department of Transportation (TxDOT) activities concerning intelligent Vehicle Highway Systems (IVHS), descriptions of current IVHS work in TxDOT, and insights as to future directions we in TxDOT see for IVHS from the state perspective.
Technical Paper

The Response of Development Engineering to Future Needs

1993-08-01
931851
Vehicle development is an essential part of a vehicle programme and can bring with it significant benefits. The author draws on previous experiences in the armed forces, motor racing and a motoring organisation to illustrate the role of development engineering. Examples are given of the evolution of development and test capabilities at MIRA to show how techniques have progressed to meet the needs of future vehicles.
Technical Paper

Shock Isolation Properties in a Swinging Mechanism Suspension Used in Motorcycles (Front Collision Safety)

1993-08-01
931846
To reduce the shock and improve the safety when a motorcycle has a front collision, the authors have created a new suspension system using a crank element and have demonstrated its usefulness. For this purpose, a test motorcycle was made by installing this system on an ordinary motorcycle with an engine displacement of 125 cc. A pulling type impact test apparatus was made to collide the test motorcycle against an obstacle. The shock absorbing characteristics of the suspension system were investigated systematically. The result shows that the impact load on the motorcycle decreased by approximately 30% when compared with ordinary motorcycles, and that the inclination of the motorcycle in a collision was significantly reduced.
Technical Paper

IVHS and the Environmental and Developmental Aspects of Transportation

1993-08-01
931847
Loss of productivity to the nation due to congestion is significant and vehicle emissions are a fall out of congestion. Vehicle emissions can be reduced through application of IVHS concepts. These are aimed at reducing congestion and smoothing the flow of traffic. They include improving high occupancy vehicle services, traffic management systems, and motorist information. Also included are route guidance and communications between the vehicle and a traffic management center. IVHS applications need to be carried out through public and private cooperation. Development of standards and applications need to include professional engineering organizations working together.
Technical Paper

Electric Vehicle Energy Conservation to Improve Range and Performance

1993-08-01
931834
Electric vehicle range must be extended to make electric vehicle use attractive. Other than propulsion, climate conditioning is the heaviest user of energy. An efficient, novel climate control system coupled with an energy management system is described and its energy usage is estimated and compared to that of a conventional system. The example presented here is for a shuttle bus used for carrying approximately fifteen passengers on short, frequently repeated routes, but the concepts are equally applicable to personal electric vehicles.
Technical Paper

Intelligent Vehicle Highway Systems in America: The FAST-TRAC Program

1993-08-01
931839
Prior to 1991, there had been a lot of discussion about Intelligent Vehicle Highway systems (IVHS), but very little implementation action. This changed dramatically with the formation of IVHS-AMERICA and the congressional passage of a $151 Billion, six-year Surface Transportation Bill. The Intermodal Surface Transportation Efficiency Act (ISTEA) allocates $200 Million annually for IVHS Operational Field Tests and Advanced Transportation System R&D. Within this framework, Siemens has been awarded a Federal Grant to field test its Ali-Scout Advanced Traveler Information System (ATIS) in parallel with the test of an Advanced Traffic Management System (ATMS) in Oakland County, Michigan. This project named FAST-TRAC, will cover approximately 200 square miles, with 100 infra-red beacon systems and up to 1000 vehicles. The ATMS will include 200-plus computer controlled traffic signals with video monitoring and vehicle detection video equipment.
Technical Paper

A Status Report on South Coast Air Quality Management District Alternative Fuels Demonstrations

1993-08-01
931833
The Technology Advancement program at the South Coast Air Quality Management District was established in 1989. A number of demonstrations of the use of alternative fuels in light-, medium- and heavy-duty vehicles have been initiated since that time. The results of completed demonstrations will be reported, along with the status of current projects and plans for future activities.
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