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Technical Paper

Electric Vehicle Development in Fiat

1991-02-01
910244
Within the strategical scope of energy conservation and improvement of human quality of life FIAT is since long time performing activities aimed at the technologies for electrically propelled vehicles for diversified applications. The electricity as energy vector allows an application flexibility to different types of vehicles, full electrics hybrid and multimode vehicles which have been developed at prototypes level or small scale production. The tactical process which has been followed is based on the three phases of: technology research and development demonstration programs and field trials production. The experience achieved within several extensively tested prototypes and pilot service allowed to put in small series production light and medium delivery vans as well as minibuses, which are now in service in Rome and other italian cities.
Technical Paper

Real Time Vehicle Dynamics Simulation: Enabling Tool for Fundamental Human Factors Research

1991-02-01
910237
A summary is given of the enabling technologies for real time high fidelity vehicle dynamics simulation. Methods of utilizing this technology to increase realism in an operator in the loop simulation are then discussed. Finally some of the research that can be performed using a high fidelity, highly realistic operator in the loop simulator is presented. Automotive engineers have long used sophisticated, batch job computer simulations of the dynamics of vehicles and vehicle subsystems to aid them in improving vehicle performance and safety. Recent technological advances have brought high-fidelity vehicle dynamics simulation into a new realm; that of real time.
Technical Paper

Characteristics Influencing Ground Vehicle Lateral/Directional Dynamic Stability

1991-02-01
910234
Lateral/directional dynamics involve vehicle yawing, rolling and lateral translation motions and dynamic stability concerns directional behavior (i.e. spinout) and rollover. Previous research has considered field test and computer simulation methods and results concerning lateral/directional stability. This paper summarizes measurements and simulation analysis of a wide range of vehicles regarding directional and rollover stability. Directional stability is noted to be strongly influenced by lateral load transfer distribution (LTD) between the front and rear axles LTD influences tire side force saturation properties, and should be set up so that side forces at the rear axle do not saturate before the front axle under hard maneuvering conditions in order to avoid limit oversteer and spinout.
Technical Paper

Numerical Simulation of Swirling Port-Valve-Cylinder Flow in Diesel Engines

1991-02-01
910263
A CAD/CAE procedure has been used for the analysis of the flow in an intake port-valve-cylinder assembly of a DI Diesel engine. The flow was simulated for both, steady state conditions and transient motored situation during intake and compression strokes. The characteristics of the helical port are analyzed, for the steady state case, in terms flow rate, generation of angular momentum flux and induced in-cylinder flow motion. The results of the simulation were correlated with experimental results, consisting of oil film visualizations on valve and intake port surfaces, and of local velocity measurements in the cylinder. The transient flow simulation shows the different characteristics of the flow motion in cylinder and piston bowl during intake and compression strokes. It was observed that the swirl generating capacity of the valve is different between the valve opening and closing phases.
Technical Paper

A PC Engine Control Development System

1991-02-01
910259
Given the rather complicated set of coordinated control inputs which are necessary to control a spark ignition engine, primary control system development and evaluation can be a very difficult task. It is also difficult to develop microprocessor systems which are flexible enough for rapid system reconfiguration. In this paper it is shown that a Personal Computer (PC) provides an excellent solution to this common problem. Possible execution time problems are avoided by the use of a special multitasking environment and simple external hardware. The external hardware takes care of the cycle to cycle fueling and spark advance timing calculations. The PC itself uses its execution time only for calculating new fueling pulse widths and spark advance angles when the operating point of the engine changes. There is also extra computing capacity available for system simulations, condition monitoring, fault detection or perhaps driver information.
Technical Paper

Development of New Electronically Controlled Fuel Injection System ECD-U2 for Diesel Engines

1991-02-01
910252
To meet the 1990s' requirements for diesel engines, the realization of innovative fuel injection system has been expected. Thus the fuel injection system named ECD-U2 was newly developed. ECD-U2 is the electronic unit injector system with high pressure common rail of which features are explained as follows; Fully electronic and flexible control in fuel quantity and injection timing. Adjustable injection rate shape Optimum injection pressure control Superior packageability and low drive torque loss. In this paper, design strategies, actual hardware configurations and some test results of ECD-U2 are described.
Technical Paper

Ford Races Its EEC-IV Electronic Engine Control Unit to Improve Production Vehicle Performance and Durability

1991-02-01
910253
In 1984, Ford Motor Company Electronics Division began to develop a version of its (production) EEC-IV electronic engine control unit that could provide the precise monitoring and command functions needed for the company's new turbocharged 1.5 liter Formula One V-6 racing engine. The electronic engine control system was necessary to allow the new engine to operate reliably at the limit of its structural integrity, while producing a horsepower/liter ratio at. least 10 times that of typical production powerplants. Ford Electronics Division is now applying the lessons learned on three generations of racing EEC-IV units, for both turbocharged and naturally aspirated racing engines, to improve the performance and durability of its passenger vehicle engines. This paper: Acquaints engineers with the electronic configuration of the EEC-IV unit. Discusses engine monitoring, control and diagnostics features traded between racing and production applications.
Technical Paper

Zinc-Air Powered Electric Vehicle Systems Integration Issues

1991-02-01
910249
Dreisbach ElectroMotive, Inc. (DEMI) is developing and testing a maintenance-free wall-plug rechargeable Zinc-Air Battery to power Electric Vehicles. This new battery technology offers over 200 mile vehicle range capability from very low cost, commonly available raw materials. This paper will focus on the preliminary systems integration needed by an electric Vehicle to operate these air breathing batteries in various common environments. Air cooling and reaction air requirements will be covered as well as the actual systems used to implement these requirements in a Chrysler minivan* which is sponsored by Southern California Edison (SCE). In addition, the projected system implementations of Zinc-Air batteries in automobiles and multi-use vans will be presented.
Technical Paper

Climate Control for Electric Vehicles

1991-02-01
910250
The vast majority of cars and small trucks are sold with factory installed air conditioning (approximately 80% in 1989). For electric vehicles to succeed in the marketplace, air conditioning will need to be offered as optional equipment, along with adequate heating and defrosting systems. While providing the level of cooling performance expected by vehicle operators, it is important that the power consumption of the air conditioning systems used in electric vehicles be minimized, to minimize penalties to vehicle range and performance. This paper summarizes the design and performance of several air conditioning systems that have been developed for electric vans over the past two years, including systems based largely on standard automobile air conditioning components and more advanced systems using high performance heat transfer components and a variable speed refrigerant compressor.
Technical Paper

A High Torque, High Efficiency CVT for Electric Vehicles

1991-02-01
910251
Epilogics, a young engineering firm in Los Gatos, CA, has developed the first fully geared, high torque, high efficiency, infinitely variable transmission suitable for automotive applications. The IVT has particular significance to electric vehicles because it can provide a highly efficient, yet exceptionally controllable means to regenerate power throughout the normal braking cycle (allowing regeneration even at near-zero vehicle speeds). Under normal operating conditions, the efficiency of the Epilogics transmission exceeds 90% as derived mathematically and corroborated experimentally. The device does not rely on traction to transmit torque and can therefore match the torque capacity of any typical gear drive. The size, weight, and cost of the device closely approximates that of a four-speed transmission suitable for the application.
Technical Paper

A Review of the Development and Use of Neuber's Rule for Fatigue Analysis

1991-02-01
910165
With the advent of strain controlled fatigue testing, strain gages and the local strain approach for fatigue analyses, designers must be able to assess the state of strain in a notch in order to predict the structural integrity of many mechanical components. A great deal of research effort has been expended over the past thirty years to develop fundamentally sound techniques for estimating cyclic notch strains using only elastic stress information and elastic-plastic axial material data. Neuber's rule has become the most widely utilized approach for engineering notch strain estimation. The original approach has undergone a wide variety of modifications for its use in cyclic loading and fatigue analyses. This paper reviews the origin of Neuber's rule and its development for use in fatigue design. The limitations of the approach are discussed, along with the recent efforts by several researchers to overcome these restrictions.
Technical Paper

Applications of High Performance P/M Aluminum in Internal Combustion Engines

1991-02-01
910156
Powder Metallurgy (P/M) renders the possibilities to tailor material properties using rapid solidification or mechanical alloying processes totally different to the options of ingot metallurgy (I/M). For demanding applications in internal combustion engines new materials have become more important because of environmental and/or performance reasons. Weight reductions to improve the performance or reduce the consumptions and consequently the amount of exhaust gases and increase of temperatures at different locations of an engine need better aluminum materials. P/M solutions are described from the point of view of material's processing and general properties. The potential for automotive pistons is discussed with several examples.
Technical Paper

Sliding Surface Profiling of Plain Journal Bearings

1991-02-01
910158
Several cases of rod bearing shells assembled in highly loaded engines have been reported to show premature wear of the sliding surface, more specifically the electroplated lead-tin overlay. To understand these phenomena and overcome such occurrences, an analytical method has been developed to simulate the operation of specially designed journal bearings featuring circumferential profiling of the sliding surface. The resulting computer program solves the Reynolds equation taking into account a non-circular bearing surface, thus allowing for a customized design which extends operational component life through minimum oil film thickness (MOFT) increase and peak oil film pressure (POFP) and bearing back temperature (BBT) reduction. Theoretical results show an effective way to prevent premature wear.
Technical Paper

Cost Effective Finishing of Powder Forged Connecting Rods with the Fracture-Splitting-Method

1991-02-01
910157
The powder forging process closes the gap between conventional powder metallurgy and die forgings. Adequate shape of the preform and strict respect of its given volume avoids forging burrs and delivers closer tolerances. Powder Forging achieves higher density and therefore remarkably improved mechanical properties as compared to the conventional PM process. An example of application for a component with high dynamic stresses is the connecting rod. High precision and low weight tolerances already lead to less machining operations on sinterforged connecting rods than on classical forged or cast components. Using the patented KREBSÖGE fracture splitting procedure, subsequent costly machining operations become obsolete. This leads to remarkably lower investments for new machining lines and to cost savings for production.
Technical Paper

Engine Bearing Contact Pressure Simulations with Thermal Effects

1991-02-01
910159
A numerical procedure to determine the contact pressure between the engine bearing and block is presented in this paper. As examples, the pressure distributions for both the cast iron and aluminum blocks are calculated. The variations of the contact pressures at different temperatures are also studied. Numerical results indicate that the retention of the bearing is accomplished primarily by the high contact pressure around the bearing edges for grooved bearings. A force diagram explaining this phenomenon is provided. In addition, a simple equation evolving from elasticity theory is included for a quick determination of the contact pressure.
Technical Paper

A Study of Oil Flow and Temperature in Journal Bearings

1991-02-01
910160
With the recent trend toward increased unit load in engine bearings, problems due to lack of lubrication frequently arise, especially in crankpin bearings. We have previously investigated the influence of shaft and bearing design on the oil flow using the connecting rod in actual use under alternating loads. In this paper, we investigate the critical value of oil flow at which the Fbearing temperature rises rapidly and the influence of connecting rod rigidity on the oil flow. As a result of these tests, it was discovered that the increase in bearing temperature (ΔTj) is in inverse proportion to oil flow (Qj),tests resulting in a single curve expressed by ΔTj = E1/Qj + E2, that the critical oil flow (Qc) varies according to Qc = Const. • E1, and that connecting rod rigidity greatly influences the oil flow (specifically, the greater the rigidity, the less oil).
Technical Paper

Biaxial Torsion-Bending Fatigue of SAE Axle Shafts

1991-02-01
910164
Variable amplitude torsion, bending, and combined torsion and bending fatigue tests were performed on an axle shaft. The moment inputs used were taken from the respective history channels of a cable log skidder vehicle axle. Testing results indicated that combined variable amplitude loading lives were shorter than the lives of specimens subjected to bending or torsion alone. Calculations using strain rosette readings indicated that principle strains were most active around specific angles but also occurred with lesser magnitudes through a wider angular range. Over the course of a biaxial test, cyclic creep narrowly limited the angles and magnitudes of the principal strains. This limitation was not observed in the calculated principal stress behavior. Simple life predictions made on the measured strain gage histories were non-conservative in most cases.
Technical Paper

Development of Three Layers Copper-Lead Bearings for Higher Speed Automotive Engines

1991-02-01
910161
As the recent automotive engines are designed for higher performance, the rotating speed of the engines have been increased drastically. Therefore the engine bearings should be further improved to have better anti-seizure and wear properties under the high temperature at the high rotating speed. The authors have analyzed the necessary functions of the three layers copper-lead bearings at such operating conditions, and then improved and developed the overlay and the copper based bearing alloy with steel back. Physical and chemical properties for this new bearing were studied. Then the bearing performance tests were carried out including the high speed seizure tests and engine tests. From these test results, it was confirmed that this new bearing could be applied for the recent very high speed automotive engines.
Technical Paper

Fuel Injectors in Diesels With Large Needle-Barrel Clearance

1991-02-01
910183
An attempt to operate a diesel engine using the so-called hydraulic fuel injector with large clearance between the needle and its barrel was carried out experimentally. In this type of injectors, the spring force was substituted by a pressurized hydraulic oil to control the needle motion. Various factors affecting the injection system, for both hydraulically and spring loaded injectors, were also theoretically simulated and tested. The present study confirmed. according to both the experimental and theoretical results, that the use of hydraulic closer of needles is a promising technique to overcome the problem of diesel engine operation with large needle clearance (7 times the standard). To maintain the best specific fuel consumption by the engine, the injection timing has to be readjusted in accordance with the increase in the needle clearance.
Technical Paper

Advanced In-Line Pump for Medium-Duty Diesel Engines to Meet Future Emissions Regulations

1991-02-01
910182
This paper describes the Nippondenso in-line pump system designed for U.S. 1991 emissions regulation for medium duty diesel engines. With the combined use of the further improved in-line pump, NB-S and the multi-hole nozzle with a smaller orifice diameter, the required injection pressure of 100 MPa to 120 MPa at the nozzle can be achieved. However, some problems to be resolved exist in the subject fuel injection system: (1) secondary injection, (2) cavitation erosion of injection pipe, (3) higher pressure sealing of fuel, (4) undesirable fuel delivery curve vs. pump speed (called “Trumpet Shape” fuel delivery curve) Thus technical measures to cope with those problems are explained in details.
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