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Technical Paper

Electric Hybrid Drive Systems for Passenger Cars and Taxis

1991-02-01
910247
Various hybrid drive configurations are described and their advantages and disadvantages for application in passenger cars are discussed; specifically, these are the series hybrid, the parallel hybrid, hybrid drives with added torque and speed, single and two-shaft hybrids. The Volkswagen and AUDI group has developed different vehicles with hybrid drive for various applications. These vehicles are described and test results are presented on their energy consumption, emissions and driving performance. In conclusion, some considerations are pursued concerning their chances on the market in different scenarios.
Technical Paper

Electrically Propelled Vehicles at BMW - Experience to Date and Development Trends

1991-02-01
910245
Back in the first two decades of automobile development, electric propulsion was a serious competitor for the internal combustion engine. Electrically-propelled vehicles, however, soon proved unable to satisfy users' increasing performance demands in terms of range, acceleration, top speed and hill-climbing, together with such factors as operating life, initial purchase price, running costs and reliability. Engineers investigating electric propulsion today face precisely the same unwelcome legacy as their predecessors, despite many and varied attempts in the meantime to improve the components of the electric vehicle's drive system (energy storage device, motors, controller). Progress in battery development, particularly in the case of the NaS system, has nevertheless enabled us at least partly to overcome the previous problems associated with electric drive systems, though it cannot be claimed that all obstacles to its commercial application have been eliminated as yet.
Technical Paper

Natural Gas Hybrid Electric Bus

1991-02-01
910248
The design and predicted performance of a hybrid electric powered transit bus is described. The bus is a 7.6 meter (25 ft), 24 passenger vehicle that incorporates a low floor design and rear door accessible to handicap passengers. The low floor and rear door are made possible by the use of individual high power density permanent magnet motors driving the rear wheels. The hybrid electric drive system consists of a compressed natural gas fueled internal combustion engine that drives a generator which in conjunction with storage batteries supply power to the two traction motors.
Technical Paper

An Examination of the Maneuverability of an All Wheel Steer Vehicle at Low Speed

1991-02-01
910241
With the goal of improving the driver's steering performance, the four(all) wheel steering(4WS) system was designed, and theoretical and experimental analysis of the 4WS system was investigated. In the 4WS system the low speed maneuverability is better due to a smaller turning radius. In reality, however, the opposite steering of the rear wheels could be counter-productive for certain maneuvers as shown in the Fig.1. In this paper, this counter-productivity is called the parking problem. The objective of this study is to prevent the parking problem and to maintain the maneuverability of the 4WS vehicle. To accomplish this goal, a new concept of the 4WS system for the low speed range has been introduced.
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

Performance Testing of the Vehma G Van Electric Vehicle

1991-02-01
910242
This paper presents the results of performance characterization testing of two prototype Vehma G Van electric vehicles (EVs). Testing was performed at the Electrotek Electric Vehicle Test Facility (EVTF) as part of the Electric Power Research Institute (EPRI)/Electrotek EV Program. The G Van is a GMC full-sized van converted to electric propulsion by Vehma International of Toronto, Ontario. One of the vans tested at the EVTF was a five-passenger model, the other was a two-seat cargo van. These vehicles utilize tubular-plate lead-acid batteries and dc powertrain system components produced by Chloride EV Systems of Redditch, England. Performance testing was conducted according to the EPRI/Electrotek EV Test Plan and included measurement of driving range at 56 km/h, on the SAE J227a C cycle, and on the Electrotek-defined Urban route. Vehicle top speed, maximum acceleration, dc and ac energy consumption, hill climbing, and braking capabilities also were measured.
Technical Paper

Correlation Analysis of Open/Closed Loop Data for Objective Assessment of Handling Characteristics of Cars

1991-02-01
910238
A new method -the stochastic lane-change maneuver- has been developed for the assessment of active driving safety in the closed-loop on the Daimler-Benz driving simulator. The characteristic data of 24 ordinary drivers and four vehicle variants defined by this method were correlated with the frequently used open-loop data of the vehicle variants and the subjective assessment of the drivers. The results show that the closed- loop assessment correlates much better (R=0.996) with the subjective assessment by the ordinary drivers than the handling data of the open-loop (R=0.717).
Technical Paper

Stratification of Swirl Intensity in the Axial Direction for Control of Turbulence Generation During the Compression Stroke

1991-02-01
910261
Control of turbulence during the compression stroke is suggested by both theoretical calculations and experimental results obtained with an LDV measurement in a motored engine. The authors have found experimentally that when an axial distribution of swirl intensity exists, a large-scale annular vortex is formed inside the cylinder during the compression stroke and this vortex generates and transports turbulence energy. A numerical calculation is adopted to elucidate this phenomenon. Then, an axial stratification of swirl intensity is found to generate a large-scale annular vortex during the compression stroke by an interaction between the piston motion and the axial pressure gradient. The initial swirl profile is parametrically varied to assess its effect on the turbulence parameters. Among calculated results, turbulence energy is enhanced strongest when the swirl intensity is highest at the piston top surface and lowest at the bottom surface of the cylinder head.
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

Control System for a Low Emissions Natural Gas Engine for Urban Vehicles

1991-02-01
910255
Natural gas has been the subject of growing interest as a low emissions alternative to conventional automotive engine fuels. The development of a control system for a very low emissions heavy-duty natural gas engine is described. The engine is intended for city bus applications, with emissions targets set well within US 1994 levels. The engine uses a stoichiometric air-fuel mixture with exhaust gas recirculation and a three-way catalyst. The control system was implemented on a prototype hardware architecture designed to facilitate algorithm development. The control system software was constructed from a number of fundamental modules. Good steady-state and transient air-fuel ratio control was particularly important for maintaining optimum catalyst efficiency and hence minimum emissions. To achieve this, the air-fuel ratio control system used solenoid gas injectors and lambda feedback.
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

Unburnt Hydrocarbon Measurement by Means of a Surface Ionisation Detector

1991-02-01
910254
Recent studies in the USA have revealed that the catalysts (which are universally fitted to gasoline automobiles) are failing in service to an unacceptable extent. Although the reasons for the failures are not completely clear, it seems that misfiring, leading to highly exothermic reaction in the catalyst, may be responsible for the damage. Legislation is to be enacted later in this decade to address this problem by requiring on board diagnostic (OBD) systems which can measure misfire, as well as catalyst hydrocarbon (HC) conversion efficiency. Although some ideas have been suggested for the OBD requirements, no fully satisfactory sensor technology has yet appeared. This paper describes a novel hydrocarbon sensor based on a surface catalysis principle. The fundamental studies reported here have been made with the automobile application in mind. A catalytic chemi-ionisation model is proposed in order to enhance our understanding of this surface ionisation.
Technical Paper

The Modelling and Calculation of a Turbulent Premixed Flame Propagation in a Closed Vessel: Comparisons of Three Models With Experiments

1991-02-01
910265
The modelling of a turbulent premixed flame propagating in a constant volume vessel has been studied and compared with experiments. Three models including step by step the turbulent mixing, the flamelets propagation for wrinkled flames, and the flamelets stretching, interactions and thickening when the chemistry is not very fast, have been tested. The experiment considered here allows the knowledge of the turbulent kinetic energy and the turbulence scale at the time of the spark, and avoid any problem of spark fluctuations and residual gases, but displays again “cyclic variations” and the comparison concerns ensemble averages. The results of comparisons is that the agreement concerning the flame brush propagation is improved from the simplest to the largest model, when considering a domain in which in which varies from 2. to .75 and from 2. to 0.4 .
Technical Paper

Motor Vehicle Pollution in Eastern Europe: A Case Study in Hungary

1991-02-01
910171
The recent developments in Eastern Europe create many opportunities as well as challenges with regard to motor vehicle pollution. Using Hungary as an example, this paper shows that even with a relatively low per capita motor vehicle population compared to Western Europe, motor vehicle pollution problems are starting to emerge in Eastern Europe (on top of already severe stationary source pollution problems in many of these countries). Using Hungary as a prototype for several other countries, the purposes of this paper are to review the current motor vehicle air pollution situation in Eastern Europe, to describe the future which is likely to emerge if current trends continue and to summarize the potential impact of a variety of control options.
Technical Paper

On-the-Road Durability and Performance of TWC Exhaust Emission Control Under Real Nordic Driving Conditions

1991-02-01
910172
The temperature regime of driving conditions in Nordic countries is very wide. This may have some effect on the performance and durability of the emission control systems used in todays vehicles, because normally these are designed with a less rigorous environment in mind. This paper describes durability and cold-start performance results obtained with two current technology TWC-cars in a full 80,000 km's on-the-road test under realistic driving conditions in Finland. The temperature extremes during the 24-month test period ranged from -28° to + 28°C. All vehicles were operated in day-to-day traffic as normal passenger cars without using any predetermined driving pattern. This practice is in contrast to the standardized durability run. The evaluation of long-term emissions performance showed a reasonable low deterioration over the test. However, at an early stage of the test one of the cars suffered from a mechanical failure in the converter unit leading to reduced performance.
Technical Paper

The Effect of Catalyst Ageing on the Composition of Gasoline Engine Hydrocarbon Emissions

1991-02-01
910174
Twenty-three hydrocarbons were measured in the exhaust gases from a Volvo passenger car fitted with a 2.3 litre gasoline engine. Measurements were made in the absence of a catalyst, and in the presence of a fresh and an aged three-way catalyst, with particular attention being paid to the emission of benzene and other light aromatic compounds. Loss of catalytic activity through ageing led to an increase in hydrocarbons of ∼ 200% from 0.22 to 0.62 g/mile. Loss of activity was most evident for certain compounds notably alkanes (paraffins) although large increases in aromatic emissions were also apparent; catalytic control of ethyne (acetylene) was, however, completely maintained by the aged catalyst. Thus the work reported here demonstrates the selective manner in which a catalyst operates depending upon the chemical structure of hydrocarbons, and how this influences catalyst performance loss via ageing.
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.
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