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HELIOS is a program for calculation, simulation and analysis of lighting problems expecially designed for car lighting technologies. Base is an “experiment” in which optical elements and theire features are described. Example: The reflector is defind by CAD-data and the surface is reflective. The result of simulation will be a light distribution. The performance has to be analysed. The LDE gives us the possibility to analyse light distribution strategies before calculation of the reflector surface itself. It is a “virtual light world”. This reduces developing time and costs and gives a help to find the best technical solution for complex illumination problems.

The thermal performance of an automotive fog lamp reflector is predicted with a computational fluid dynamics program. The 2D, steady-state heat transfer model accounts for convection and radiation within the enclosure, conduction through the reflector walls, external convection and radiation losses, and transmission through the lens. A good comparison of the predicted reflector temperatures with experimental thermocouple and infrared data suggests that the specular component of the inner metal coating plays a secondary role in the overall heat transfer and that a detailed thermal model of the bulb is not required. The radiant exchange with the tungsten filament and the conductive energy losses through the bulb connections are accounted for by specifying an appropriate heat flux at the bulb surface, and the transmission of radiant energy through the lens is modeled with an appropriate heat sink.

The U.S. currently requires that reai-view mirrors installed as original equipment in the center and driver-side positions be flat. There has recently been interest in using nonplanar mirrors in those positions, including possibly mirrors with large radii (over 2 m). This has provided additional motivation to understand the effects of mirror curvature on drivers' perceptions of distance and speed. This paper addresses this issue by (1) reviewing the concepts from perceptual theory that are most relevant to predicting and understanding how drivers judge distance in nonplanar rearview mirrors, and (2) reviewing the past empirical studies that have manipulated mirror curvature and measured some aspect of distance perception. The effects of mirror curvature on cues for distance perception do not lead to simple predictions. The most obvious model is one based on visual angle, according to which convex mirrors should generally lead to overestimation of distances.

Until the late 1980s, the technology used in automotive lighting was relatively limited. Designers had little styling freedom as the main prerequisite of car makers was to reduce the size and increase the performance of lighting systems. VALEO invented SC (complex surface) technology to improve luminous efficiency. The first cars equipped with SC were the EAGLE PREMIER in the United States the CITROEN XM in Europe. SC2 followed. SC2 incorporates reflector technology that controls both the vertical and horizontal deviation of the light and increases styling freedom especially for fog lamps. The latest in the line of high performance lamps, SC3, was developed to optimize beam patterns in order to meet statutory requirements whatever bulb is used. Because SC3 uses a clear lens with an optical reflector, styling can be much more original and the angle of the lens can be increased to 60°.

Models using contrast as the measure of discernibility or detection of roadway obstacle on non-lighted roadways have not recognized the lighting effects caused by the lateral spacing of headlamps on the vehicle. When the only significant sources of roadway light are a vehicle's headlamps, shadows on the roadway behind and to the left and right of the obstacle are viewed simultaneously with the obstacle itself. It can be shown that in certain obstacle-sighting situations, where there is little or no significant background light from sources other than the headlamps themselves, sufficient contrast is provided by the shadow outlines. Shadows created by the lateral spacing of the headlamp light sources and the driver's eyepoint, framing one or both sides of the obstacle, serve to outline the illuminated obstacle on the roadway in front of a vehicle.

This paper describes the results of an experimental programme designed to investigate some effects of intake flow-generated turbulence on rates of combustion and emissions formation in a 91mm bore direct injection diesel engine. Swirl and squish were eliminated as far as possible, in order to isolate the desired effects. This was achieved by re-modelling the inlet port and by replacing the deep bowl piston cavity with a flat-topped version, with the same compression ratio. Tests were carried out with three inlet valves: a standard engine Valve (“A”) and two drilled shrouded valves, one with 15 x 6 mm dia. holes (“B”) and one with 40 x 3.5 mm dia. holes (“C”). The turbulence characteristics associated with each valve were first determined on a steady flow rig, using LDA based surveys of velocity distributions at different downstream distances. The objective was to measure absolute levels of turbulence intensity and to study the subsequent rate of decay.

The effect of ambient gas hydrocarbon content on diesel spray ignition and combustion was examined in this research project. A single-stroke rapid compression machine was used to prepare the ambient gas pressure and temperature before the diesel fuel injection process. Variations of ambient gas composition were achieved by adding different quantities of methane and propane to the intake air, the content ranged from 0.0 to 0.6 equivalence ratio. The two-color method was applied to analyze the flame temperature and KL factor was determined from the colored flame image taken by a high-speed camera. Also, compression ignition characteristics of lean methane-air and propane-air mixtures were examined.

Typical DI diesel engines operate with fuel injection taking place within a range of about 30 crank angle degrees before top dead center, at the end of the compression stroke. When injection takes place far earlier, at the beginning of the compression stroke, another form of combustion occurs, which we termed PREmixed lean Diesel Combustion, or PREDIC. With PREDIC operation, self-ignition occurs near top dead center and NOx emissions are drastically lower. When ignition occurs, the fuel-air mixture is thought to be nearly homogeneous, with only slight heterogeneity. Appropriate fuel spray formation is very important for successful PREDIC operation. Using a single-zone NOx formation model, calculations showed that the mean excess air ratio in the PREDIC combustion zone was 1.87, which resulted in very low (20 ppm) NOx emissions. Conventional combustion at the same conditions resulted in a mean combustion zone excess air ratio of 0.88.

For some years now the new HID technology has been used for headlamp systems to improve safety and comfort during night time driving. A new generation of projector type headlamps starts series production in 1997. The characteristics of the HID bulb and the specific requirements of the light distribution make it necessary to calculate special optical systems to control the high amount of light. There are different possible design strategies. On one hand, it is possible to improve the light pattern, e.g. increase the luminous flux and the range. On the other hand it is possible to build a system with extremely small dimensions. Such a system ensures an excellent light quality even in smallest headlamps and gives way to new styling possibilities. To match such different targets, some parameters of the reflector and the lens have to be optimized. Some examples of projection headlamps which are designed for different applications will be discussed.

Signal lamp for a motor vehicle with a complex reflector design is presented. The reflector is composed of set of rectangular bicubic Bezier ‘pillows’ creating desired horizontal and/or vertical light spread. Cover lens with no or weakly-spreading optics is assumed. Mathematical background is discussed in part 2 - parametric equations for individual pillow are presented, equations for control points ensuring proper optical function of the pillow are derived and parameter controlling intensity distribution of output beam is introduced. Option to prevent beam asymmetry of conventional signal lamps with big rake angles of cover lens using ‘semicomplex’ optical system (i.e. complex reflector combined with optical elements on the cover lens) is discussed, too.

A design strategy for implementing High Intensity Discharge (HID) light sources in low beam head lamps with Free-Form Reflectors (FFRs) is presented. A theoretical analysis of a light source image formed by each portion of a reflector is presented as well as a strategy for using those images to create a head lamp beam pattern. Simulation results are shown for a head lamp design using this strategy.

For the automotive industry, the styling of a car is an important feature. Since the appearance of a car is strongly characterized by the headlamp, stylistic aspects have an increasing influence on the development of headlamps. At the same time, the trend goes toward reducing the constructional volume available to the headlamp and also integrating other functions such as foglamps. To fulfill all these requirements, new reflector shapes had to be created. In this paper, different reflector concepts for low beam, high beam and foglamps are presented. They will be discussed under consideration of stylistic aspects (e.g. space for the required bulb shield, semi-clear outer lens) and technical aspects (e.g. thermal stress of plastic lenses).

In recent years, the automotive industry has seen a rapid increase in the “on-board electronics content” of vehicles. Such technology has given rise to ever increasing levels of safety, comfort and performance in this high production-volume industry. Cost considerations require that most on-board electronics be implemented on fixed-point processors. As companies look to extract more (performance) for less (implementation costs & lead time) the job of designing on-board fixed-point application software is becoming more and more challenging. This paper discusses the use of fixed-point design tools that were recently introduced in the MATRIXx® product family. These tools feature a high-performance fixed-point simulator, and a kit of interactive tools that enable engineers to study signal ranges and overflow/underflow conditions. Tools to perform trade-off studies between performance and fixed-point attributes are also discussed.

Automotive applications require complex systems with strong interaction between electrical and mechanical modes of operation. To achieve fast to market products and reduce development costs, math modeling is essential to analyze these complex mechatronic systems and accurately characterize their behavior. One of the tools widely employed by GM to address this need is Sabera®. While Sabera® is well developed in electrical and mechanical domains, it is difficult to accurately model the magnetic behavior. To alleviate this problem, the magnetic circuit is characterized by the finite element analysis program, Maxwell®, and then integrated with Saber®. This paper discusses the development of models using this process with a transmission application.

The development of modern engine mechanical systems and electronic control systems has been advanced significantly over the last few years by increased use of engine modeling. A key requirement for improved modeling will be more accurate verification of the prototype engine performance to that predicted by the model. As percentage gains in engine power, fuel economy, and emissions become incrementally smaller, accurate measurements of these parameters are more critical. In addition, as engine testing in the dyno cell moves more toward transient operating conditions which more accurately represent actual driving conditions, measurement speed of the engine and ECM performance must increase tenfold or more to fully characterize transient behavior. This paper will illustrate these points with examples of engine development problems accompanied by descriptions of the key data system requirements such as sampling speed, measurement accuracy, and triggering flexibility.

PET (Powertrain Engineering Tool) [1, 2] is based on an object-oriented hierarchy system and therefore each component (parent) has its own sub-component (child) systems. Developing explicit forms of objective functions and constraints is simple due to the object-oriented component system of PET. This system automatically recognizes the geometry of components and related design functions in its sub-component levels. This paper discusses computational efficiency, solution accuracy and robustness of software when using closed-form representatives of the derivatives of objective functions and constraints in sequential quadratic programming. Examples of generating closed-form representatives of the derivatives of objective functions and constraints in C/FORTRAN language syntax by using a symbolic processor, Mathematica [3], and mass reduction of the piston-pin are also presented.

A numerical process, which consists of free or force vortex motion, boundary element methods and optimization methods, was developed to calculate the design parameters of an axial flow fan. Rotational speed, tip and hub diameters, and number of blade were used as the input data. Stagger angle, radial varation of the blade angles, was calculated with this numerical process. Sum of the difference of the stagger angle for numerical solution and that for current design was minimized by using the optimization methods. Parameters of the computational solution, including lift and drag of an aerofoil, inlet flow angle and velocity, outlet flow angle and velocity, and variation of axiaI velocity in the radial direction, were calculated to investigate the current product of axial flow fan. Three cases were run to validate the numerical solutions. Case A and case B were the Valeo's current products; case C was the Valeo's prototype fan.

Hardware-in-the-Loop Simulation allows ECUs to be tested in a simulated environment in closed loop. Engines, vehicles, and other components the ECU normally controls are replaced by high-fidelity models executed on a real-time computer system. This paper shows that today's hardware/software technology makes comprehensive and powerful low-cost desktop simulators feasible. It is also shown that it is now possible to use the same tools for Hardware-in-the-Loop Simulation that have been used in the control development.

In today's automotive development environment it is necessary to look at the totality of an automotive system. For this approach is necessary in order to optimize system designs for reliability, manufacturability and cost. Optimization in the case of the automotive system or subsystems, entails performing trade-off studies on the different components taking into account their interactions. In doing so it is necessary to employ a mixed domain simulation tool. In the case of the Cranking and Charging System electrical, mechanical and thermal domains must be co-simulated. The focus of this paper will be to show how a typical Cranking/Charging system can be analyzed and how the appropriate design decisions can be made.

Simulation is by now considered an essential activity prior to the implementation of complex, embedded real-time systems such as automotive control units. However, the models required for a meaningful systems simulation are often heterogeneous -(such as software, hardware, hydraulics, mechanics etc.) and developed in parallel using different tools from different vendors, thereby making comprehensive system simulations very hard. An open architecture for cosimulation of heterogeneous systems and its first implementation within the MATRIXx tool family, based on the Common Object Request Broker Architecture (CORBA) is described. It allows plug-and-play cosimulations between a wide range of simulation tools and can serve as the foundation of sophisticated virtual prototyping and systems simulation activities.