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The ventilation flow inside a one-fifth-scale model of a typical mid size passenger compartment with a driver present has been investigated experimentally and computationally. In this study only one ventilation mode has been evaluated, namely the defrost mode in which air is discharged from two vents in the form of slits located along the top of the dashboard. The fluid measurements were taken using the Particle Image Velocimetry (PIV) technique to acquire the velocity distribution of the model interior. The Computational Fluid Dynamic (CFD) analysis have been implemented and simulated by using the commercial CFD code FLUENT as a tool to investigate the flow of the compartment's interior. Comparisons of the predicted velocity field with experimental data show good agreement and were qualitatively consistent.

Automotive interiors are undergoing rapid transformation with the introduction of invisible PSIR integral systems. This styling trend requires continuous class A surface for the Instrument Panel (IP) and introduces complexities in the design and analysis of PSIR integral systems. The most important criterion for airbag doors is that it must open as intended, at the tearseam, within the deployment temperature range and without fragmentation. Consequently it is imperative that in analytical simulations, the finite element model of the tearseam is accurate. The accuracy of the model is governed by (a) optimal level of refinement, (b) surface geometry representation and (c) material model. This paper discusses modeling methodology for tearseams with respect to mesh refinement and the effect of geometry.

The design of the newly developed Toyota AZ series 4 cylinder engine has been optimized through both simulations and experiments to improve heat transfer, cooling water flow, vibration noise and other characteristics. The AZ engine was developed to achieve good power performance and significantly reduced vibration noise. The new engine meets the LEV regulations due to the improved combustion and optimized exhaust gas flow. A major reduction in friction has resulted in a significant improvement in fuel economy compared with conventional models. It also pioneered a newly developed resin gear drive balance shaft.

The analysis of airflow in an automotive HVAC cowl box is complicated by the cross sectional variations and abrupt changes in airflow direction. In this study, the complex three-dimensional turbulent flow found in a generic road vehicle cowl box is investigated experimentally and computationally. An optical anemometer is used to acquire the experimental data within a white metal sheet of a cowl box. The results are then used to validate and tune a Computational Fluid Dynamics (CFD) numerical cowl model.

The introduction of innovative new technologies is related to aspects of safety and to human factors as comfort level and visual appearance. The intelligent headlamp system that is currently being developed allows the combination of the different aspects of driving comfort and safety. The top performing headlamp generations of the future will be the successors of the today’s standard low beam. By using the sensor information available in the car, the light distribution will be adapted to different driving situations and generate an optimized light distribution. Relaxed and safe driving is the goal. Investigations concerning adaptive headlamps are presented. Highway, country road, curves and turning situations are examined by investigating detection distances of standard objects and by rating safety and comfort. Photometric measurements rating glare effects during curve road driving for different headlamp control algorithms are carried out.

The shape and configuration of the air ventilation system determines the ventilation performance while influencing the design and structure of a car. It is therefore necessary to decide the configuration of the air ventilation system in the early stages of design. We tried to analyze the pressure level of the ventilation ducts from the aerodynamics simulation results added to the cowl top which had the ventilation intake duct, and so on. Thus we succeeded in designing a new development process that can be used to predict the ventilation performance in a shorter time without the use of prototypes.

Fulfillment of SULEV standards without catalyst - this is a target engineers at IAV have been working on since the middle of the 1990s. The core of this development is an advanced steam engine with a high performance burner. This burner features extremely low raw pollutant emission. This paper describes new solutions that were found to solve the challenging tasks in the development of such an engine concept.

Although computer models for vehicle and sub-system performance simulations have been developed and used extensively in the past several decades, there is currently a need to enhance the overall availability of these types of tools. Increasing demands on vehicle performance targets have intensified the need to obtain rapid feedback on the effects of vehicle modifications throughout the entire development cycle. At the same time, evolution of the PC and development of Web-based applications have contributed to the availability, accessibility, and user-friendliness of sophisticated computer analysis. Web engineering is an ideal approach in supporting globalization and is a cost-effective design-analysis integration business strategy. There is little doubt that this new approach will have positive impacts on product cost, quality, and development cycle time. This paper will show how Microsoft Excel and the Web can be powerful and effective tools in the development process.

A feasibility study is presented concerning detailed vehicle modeling, including submodels for engine, transmission mechanics and hydraulics, as well as three-dimensional chassis behavior. The study was conducted jointly by Ford Motor Company, Dynasim AB and DLR. The results demonstrate that complex behavioral models of each subsystem can be developed, used and validated independently from each other, and finally assembled together to an overall model. Therefore, this approach could be the basis to establish modeling standards that allow collaboration between model developers throughout the automotive industry.

This paper introduces the new 1.6L engine family, designed and developed by the Chrysler group of DaimlerChrysler Corporation in cooperation with BMW. An overview of the engine's design features is provided, with a detailed review of the performance development process with emphasis on airflow, combustion, thermal management and friction. This information is presented, to provide an understanding of how the engine simultaneously achieves outstanding levels of torque, power, fuel consumption, emissions and idle stability. The use of analytical tools such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) in the optimization of the engine is shown.

The combination of physical models of an advanced engine control system was proposed to obtain sophisticated combustion control in ultra-lean combustion engines, including homogeneous compression-ignition and activated radical combustion. Physical models of intake, combustion (including engine thermodynamics), and transmission were incorporated, in which the effects of residual gas from prior cycles on intake air mass and combustion were taken into consideration. Control of the in-cylinder air/fuel ratio, exhaust temperature and engine speed during start, post-start and gear shifting phases was investigated using simulations.

A new CAD-based model of the occupant/driver for interior and seat design has been developed. Unlike traditional automotive iterative design methods that begin with a 2D human manikin in an environment based on the location of H-point, the 3D ERL manikins determine the initial design positions of multiple occupants based on the simulated interactions of seat, driver package, skeletal linkage system and deflected human tissue. The 3D ERL human body representations come from measurements of posture-critical skeletal landmarks on 102 test subjects combined with measurements of “deflected human tissue” data from 60 test subjects. The result is a set of three dimensional, posture-biofidelic manikins that a computer algorithm optimizes the driver's workplace environment to fit the population range of sizes and postural preferences.

Comfort is more than ever one of the major factors of car performance. The seat, a central component of the vehicle interior, contributes heavily to this perception. The increasing partnership between car manufacturers and automotive system equipment manufacturers pushes Faurecia to propose not only standard components but also a complete seat, with its functional and safety criteria, as well as those including comfort. This last aspect is what we will treat here. We are going to show you how the Soft & Firm Seat, a technical innovation developed by Faurecia, improves seat tactile and contact comfort behavior perceived by customers. This innovation has been designed according to Faurecia comfort methodology, using subjective assessment, objective measurements and simulation. Its validation concerns tactile and contact comfort, interactions with other comfort aspects and consequently the improvement of overall comfort.

Semi-solid metal forming processes are of large industrial interest for the production of various components. Reduction of macro-segregation, reduction of porosity, possibility of near net shape are the principal advantages over casting, forging and powder metallurgy techniques. This paper gives a brief description of the Thixomag® process applied to a AZ91D magnesium alloy. As it is well known, special material properties are required for the thixoforming process. It is especially necessary to homogenize the temperature along the billet during the induction reheating. This homogenization of temperature enables to avoid the coarsening of the primary solid phase and defects in the final part. To determine the optimum conditions and to reduce the process duration, numerical simulation has been used. A 2D model, where thermal and electromagnetic are coupled, was built.

This paper presents and validates a model of fatigue crack propagation in resistance spot welded joints; this model is called the “Structural Stress Model” (SSM). Important features of the SSM are that it is based on the physical evidence of fatigue in spot welded joints and on well-accepted descriptors of fatigue more generally. Furthermore, it is usable by designers evaluating fatigue response of structures containing multiple welds. Underlying assumptions of the SSM are also reviewed.

In the present study, several welded beam and plate specimens are fabricated using an electrical resistance type spot welder and studied experimentally applying the frequency response function approach. The experimental data is used to guide the dynamic finite element modeling effort, and to determine the weld joint representation that most accurately characterizes the measured dynamic response. The results reveal the compliant nature of the spot welds at higher frequencies and in applications consisting of more complex geometrical structures and boundary conditions. This finding shows the inadequacy in the classical rigid element representation that is widely used in current dynamic modeling practices.

ACRs (All Clear Reflectors), also widely referred to as FFRs (Free Form Reflectors), were designed in general and intelligent ways using a NURBS surface for the mathematical modeling of the reflector shape and artificial intelligence as the optimum design algorithm. An ACR, which consists of a continuous surface reflector and clear outer lens, offers styling advantages and provides a high quality light performance. The clear outer lens of an ACR remains efficient even with a highly inclined shape, as in the design of a sports car, plus the complete clearness of the reflector surface eliminates the nuisance of stray light caused by the steps between individual segments of multi-faced reflectors. The design technique of an ACR was also successfully applied and tested with all types of lamps, including low beams, high beams, fog lamps, and turn signal lamps.

This paper discusses the definition and performance of the warning algorithm in a potential Rear-End Collision Avoidance System (RECAS). Given vehicle range, velocity, and leader deceleration data, the warning algorithm computes whether imminent braking is required to prevent a collision with a vehicle directly ahead, and determines whether a warning should be given to alert the driver. The result of the study is an estimate of the number of warnings per hour under normal driving conditions for various types of drivers.

In order to prevent injuries due to automatic functions like express- and comfort-opening/closing of power operated window-lift and sunroof systems, mechanisms for detecting obstacles have to be established. The main related regulations are the 74/60/ECC and the FMVSS 118. In this paper we present a unified approach for smart actuators that bases on monitoring the rotational speed of the armature. The advantages have been worked out with the aid of system simulation and proven with tests under realistic and extreme scenarios. The presented results are mainly focused on a sunroof project, which is upcoming for an European car platform in 2001 and is specified to fulfill both regulations simultaneously.

A biaxial test procedure is used to assess the constitutive properties of polymers in tension. The constitutive constants are derived for high strain rate applications such as those associated with crashworthiness studies. The test procedure is used in conjunction with a time- and strain-dependent quasi-linear viscoelastic constitutive law consisting of a Mooney-Rivlin formulation combined with Maxwell elements. The procedure is demonstrated by describing the stress vs. strain relationship of a rubber specimen subjected to a step-relaxation input. The constitutive equation is transformed from a nonlinear convolution integral to a set of first order differential equations. These equations, with the appropriate boundary conditions, are solved numerically to obtain transient stresses in two principal directions. Material constants for use in the explicit LS-Dyna non-linear finite element code are provided.