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From the end of 1997, Kyoto Protocol has forced system engineers to look more about their system green house contribution. In this paper, we use Total Equivalent Warming Impact analysis to understand what are the key issues between various A/C systems possible for the future. Estimation of TEWI is done using experimental data but also precise simulation results when available. A/C systems using refrigerant HFC R134a and C02 R744 are taken into account but also system based on electric compressor due to the possible change in automotive engine technology to hybrid and fuel cells. Two major topics are considered: the first one is relative to acceptable leakage of refrigerant and the second one is the control of the A/C system around optimal conditions in respect with the fuel consumption.

The modeling of the energy storage system (ESS) of a Hybrid Electric Vehicle (HEV) poses a considerable challenge. The problem is not amenable to physical modeling without simplifying assumptions that compromise the accuracy of such models. An alternative is to build conventional empirical models. Such models, however, are time-consuming to build and are data-intensive. In this paper, we demonstrate the application of an artificial neural network (ANN) to modeling the ESS. The model maps the system's state-of-charge (SOC) and the vehicle's power requirement to the bus voltage and current. We show that ANN models can accurately capture the complex, non-linear correlations accurately. Further, we propose and deploy our new technique, Smart Select, for designing ANN training data.

The aim of this paper is to describe a unified approach to modeling the energy efficiency and power flow characteristics of energy storage and energy conversion elements used in hybrid vehicles. Hybrid vehicle analysis and design is concerned with the storage of energy in three domains - chemical, mechanical, and electrical - and on energy conversions between these domains. The paper presents the physical and mathematical basis of this modeling approach, as well as a modular simulator that embodies the same basic principles. The use of the simulator as an analysis tool is demonstrated through the conceptual design of a sport-utility hybrid drivetrain.

The CY2000 cornerstone goal of the Partnership for a New Generation of Vehicles (PNGV) is the demonstration in CY 2000 of a 5-passenger vehicle with fuel economy of up 80 mpg (3 l/100km). As a PNGV partner, GM will demonstrate a technology-demonstration concept vehicle, the Precept, having a lightweight aluminum-intensive body, hybrid-electric propulsion system and a portfolio of efficient vehicle technologies. This paper describes: 1) the strategy for the vehicle design including mass requirements, 2) the selection of dual axle application of regenerative braking and electric traction, and 3) the complementary perspective on energy management strategy. This paper outlines information developed through systems analysis that drove technology selections. The systems analyses relied on vehicle simulation models to estimate fuel economy associated with technology selections. Modeling analyses included consideration of both federal test requirements and more severe driving situations.

Technologies applied to the Nissan Tino Hybrid, marketed in March 2000, in Japan, are expected to evolve into the core powertrain technologies of the future, for the following technical advantages inherent to hybrid EVs: 1 Regeneration of deceleration energy 2 Motor driven propulsion at low speed, combined with power-assisted operation in the mid- and high-load ranges. It is expected that a number of models will be introduced to the market in the future, which pursue these advantages in various forms, resulting in HEV technologies to accelerate the use of electric power for the vehicle. Fuel cell vehicles will be included in this future scenario. In this paper, our view on the future HEV technologies will be described. In addition, the latest technologies applied to the Nissan Tino Hybrid will be introduced.

This paper describes the design and construction of a fuel cell hybrid electric vehicle based on the conversion of a five passenger production sedan. The vehicle uses a relatively small fuel cell stack to provide average power demands, and a battery pack to provide peak power demands for varied driving conditions. A model of this vehicle was developed using ADVISOR, an Advanced Vehicle Simulator that tracks energy flow and fuel usage within the vehicle drivetrain and energy conversion components. The Virginia Tech Fuel Cell Hybrid Electric Vehicle was tested on the EPA City and Highway driving cycles to provide data for validation of the model. Vehicle data and model results show good correlation at all levels and show that ADVISOR has the capability to model fuel cell hybrid electric vehicles.

Oak Ridge National Laboratory's (ORNL) computer code PMM_IDT (Permanent Magnet Motor Interactive Design Tool) was used to study the sensitivity to changes in design parameters at constant power output and scaling laws for similar designs with different rated power outputs. The base design used was a radial-gap motor with 30 kW of net output characteristic of the PNGV “Series” vehicles. Sensitivity parameters studied were active length, magnet and air gap thicknesses, and number of magnets. Power output variation approaches considered were active length, stator external diameter, and rotor external diameter. The impact on efficiency, cost, weight, specific power, cooling requirements, drive current and voltage requirements, and demagnetization margins are presented. Common constraints in this study are: Hollow rotor, trapezoidal back emf - 212 V maximum - and double layer winding leading to an even number of turns per slot

Composite materials have the potential to reduce the overall cost and weight of automotive structures with the added benefit of being able to dissipate large amounts of impact energy by progressive crushing. To identify and quantify the energy absorbing mechanisms in composite materials, test methodologies were developed for conducting progressive crush tests on composite specimens that have simplified test geometries. The test method development focused on isolating the damage modes associated with the frond formation that occurs in dynamic testing of composite tubes. A new test fixture was designed to progressively crush composite plate specimens under quasi-static test conditions. Preliminary results are presented under a sufficient set of test conditions to validate the operation of the test fixture.

The history of automotive electrical systems began in 1912 with an integrated starter/generator system (i.e. the Kettering DELCO system.). These systems were soon replaced by a separate starter and generator and later replaced by alternators, which now produce about 2kW. The 21st century will debut with intense interest in integrated starter/alternator/damper (ISAD) systems in the 5–20 kW range. This large increase in available electric power will catalyze many new luxury, performance and convenience features––and provides modest amounts of supplemental traction. The mechatronic technology of these systems will be nearly identical to more powerful parallel hybrid systems. This paper presents an advanced ISAD system for internal combustion (IC) engines and hybrid electric vehicle applications to reduce fuel consumption, reduce emissions, and enhance energy efficiency.

It is known, that the alternator self-excitation is possible at capacitor loading [1]. From this follows, that the alternator excitation by means of capacitors connected to one or several stator windings, as from simple excitation winding is located on a rotor, is possible. In the report the excitation of the automobile alternator with claw pole rotor by means of capacitors connected to stator windings at rotor open excitation circuit is considered. Thus, for comparison the alternator idle characteristics are received both at excitation by means capacitors, and by means of a simple excitation winding. Besides the other electrical parameters of the alternator with claw pole rotor by experimental way are determined. On the basis of the received data the alternator digital model was developed, it takes into account the magnetic circuit saturation, by using of the received experimental idle characteristics.

Damage constitutive models based on micromechanical formulation and a combination of micromechanical and macromechanical effects were developed by the authors to predict progressive damage in aligned and randomly oriented carbon fiber polymer composites. The models are extended in order to account for the microcrack effect on the mechanical behavior of the composites. Progressive interfacial fiber debonding models are considered in accordance with a statistical function to describe the varying probability of fiber debonding. Finally, the complete progressive damage constitutive models are implemented into the finite element code DYNA3D to perform impact simulation of random fiber-reinforced composites for future use in advanced automotive materials. The implemented model is applicable for shell and solid elements in three-dimensional analysis, as well as axisymmetric elements in two-dimensional analysis.

In modern car, to reduce car deadweight, lightweight technology is widely used; and to improve comfortable and handling performance, many rubber bushings installed between car body and suspension. These parts have difference characteristics during car running at high speed comparing these at static state. Accounting the suspension performance has a decisive influence on a car, the flexible parts should be taken into account in the suspension/steering system simulation model. As a deviant phenomenon, the steering wheel shimmy affects the suspension's dynamic characteristics greatly. To analysis this abnormal running state, the front wheel bounce tracks were figured out by using different front suspension model. The flexible parts installed in suspension are idealized respectively as rigid poles, flexible beams or forces, hence, the rigid suspension analytical model and the rigid-elastic suspension model analytical were built respectively.

Many vehicle-dynamics models exist to study the motion of a vehicle. Most of these models fall into one of two categories: very simple models for basic analyses and high-order models consisting of many degrees-of-freedom. For many scenarios, the simple models are not adequate. At the same time, for many vehicle handling and braking studies, the high-order models are more complex than necessary. This paper presents a model that includes the dynamics that are relevant to studying vehicle handling and braking, but is still simple enough to run in near real-time. The model was implemented in such a way that it is easily customized for a particular study. Predictions from this simplified model were compared against a high-order model and against actual vehicle test data. The simulations indicate a close agreement in the results.

Active steering has received lot of attention in the recent years because of the development of vehicle stability control systems and intelligent vehicle highway systems. Active steering systems allow for correction of the steer angle to achieve the desired vehicle yaw gain. The proposed system can be easily integrated with the vehicle stability control systems that use braking to control the vehicle yaw gain. The paper describes the concept of front wheel active steering system and the design techniques involved in order to achieve the desired performance from the system. The design techniques demonstrated in the paper do not address noise (gear rattles, motor noise, gear whine etc), electromagnetic compatibility and thermal issues related to DC motor and digital controller.

This paper reviews the development and application of a computer simulation for simulating ground vehicle dynamics including steady state tire behavior. The models have been developed over the last decade, and include treatment of sprung and unsprung masses, suspension characteristics and composite road plane tire forces. The models have been applied to single unit passenger cars, trucks and buses, and articulated tractor/trailer vehicles. The vehicle model uses composite parameters that are relatively easy to measure. The tire model responds to normal load, camber angle and composite tire patch slip, and its longitudinal and lateral forces interact with an equivalent friction ellipse formulation. The tire model can represent behavior on both paved and off-road surfaces. Tire model parameters can be automatically identified given tire force and moment test data.

An automatic vehicle controller (AVC) which was specified, designed, fabricated, installed and used on a variety of vehicles, including automobiles, light trucks, and sport utility vehicles is described. The AVC controls the vehicle's steering, and input waveforms of virtually any type or complexity can be specified from computer files containing steering wheel angle commands as functions of time. Also, algorithms which use motion sensor feedback in the steering control logic can be programmed. Throttle and brake controls can also be provided.

Milliken Research Associates has developed a new simulation tool, named Vehicle Dynamics Simulation-Matlab/Simulink (VD-M/S). Produced for the government's Variable Dynamic Testbed Vehicle (VDTV), VD-M/S is an 18 degree-of-freedom simulation programmed in the Matlab/Simulink environment. It contains a detailed non-linear tire model, kinematic and compliance effects, aerodynamic loadings, etc. as do MRA's other simulation programs. Unique to VD-M/S is its development from Day One as a simulation catered to the inclusion and exploration of active systems within the vehicle.

Conventional computer models for complex vehicle components (like bushings and dampers) are often inadequate to represent behavior over wide frequency ranges, and/or at large amplitudes. New modeling methods circumvent these limitations by using laboratory measurements with neural networks. The new methods enable accurate simulation for nonlinear, frequency dependent components, having multiple inputs and outputs, under arbitrary excitation. This paper describes one such method, known as Empirical Dynamics Modeling. Examples are presented for vehicle shock absorbers and a rubber bushing. Benefits and limitations are discussed, along with requirements for interfacing to a conventional virtual prototyping environment.

This paper presents the results of a recent project of IKCo’s research center to modify the Paykan 1600’s rear suspension mechanism with the purpose of improving the car’s comfort, stability and handling qualities. The car was originally equipped with a solid rear axle with leaf springs. By replacing the original mechanism with a three-link mechanism with panhard bar and coil springs, the ride comfort and handling characteristics of the car were noticeably improved.3-D, nonlinear ride and handling models were developed and analyzed to determine the important kinematics and dynamic effects of the new mechanism on vehicle responses. To verify the analytical results, subjective tests were carried out on the vehicle. The results of these tests demonstrated remarkable improvement of the dynamics behavior of the car.

This paper describes the analysis and design of a hydropneumatic limited bandwidth active suspension system. The design is based on hydropneumatic suspension components taken from an existing European saloon. Mathematical modeling based on the well-known quarter car model is used to compare the performance of the proposed suspension with both the baseline passive system and an idealised fully active system. Practical features, such as actuator time delays and self-levelling controllers, are included in the model of fully active suspension system, and of the limited bandwidth suspension respectively. The controller design for the proposed suspension is based on limited state feedback, and the Nelder-Mead simplex algorithm was used to calculate the gains to optimise the performance index. Overall, the performance of the proposed system appears to be nearly as good as that of the idealised fully active system.