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Technical Paper

Development of an Efficient Signaling Lamp with LEDs Mounted on a Free Formed Surface

2000-03-06
2000-01-0436
In keeping with recent trends in vehicle body design, there is an increasing requirement for signaling lamps to have a more slanted and bent shape. There are also growing expectations that light emitting diodes (LEDs) will replace incandescent bulbs in signaling lamps. LEDs, however, will bring a cost problem if they are to be mounted on conventional hard printed circuit bases. We have overcome this problem by developing pressureweldable LEDs which can be attached to free formed surfaces without soldering. As a result it has become possible to design LED signaling lamps with a superb beam utilization.
Technical Paper

Daytime Running Lamps - Different Ways of Realization

2000-03-06
2000-01-0435
Many traffic accidents - not only during nighttime - are caused by late or failed recognition of moving vehicles. Daytime Running Lamps (DRL) lead to better conspicuity and thus helps to reduce traffic accidents. This has recently been confirmed in a study by Koornstra, Bijleveld and Hagenzieker [1]. Nevertheless, the extra power consumption and its environmental impact is often used as argument against the general introduction of mandatory driving with lights. We have investigated possibilities of how to realize DRL with low power consumption. Several reflector concepts have been analyzed. Existing bulbs have been considered as well as some new developments.
Technical Paper

A Unified Approach to Solder Joint Life Prediction

2000-03-06
2000-01-0454
A unified approach has been developed and applied to solder joint life prediction in this paper, which indicates a breakthrough for solder joint reliability simulation. It includes the material characterization of solder alloys, the testing of solder joint specimens, a unified viscoplastic constitutive framework with damage evolution, numerical algorithm development and implementation, and experimental validation. The emphasis of this report focuses on the algorithm development and experimental verification of proposed viscoplasticity with damage evolution.
Technical Paper

New Applications with High Flux LED in Automotive Signal Lighting

2000-03-06
2000-01-0437
Light Emitting Diodes (LED) in the field of automotive signal lighting have been well known for around a decade. The first step was the introduction of Central High Mounted Stop Lamps (CHMSL), containing 5 mm LED types with an emitter-flux of less than 1 lm. Improved designs offering more than 2 lm have made new CHMSL designs, side-markers, and the first rear combination lamp functions possible. The development of the next LED generation, supplying more than 10 lm, will extend LED technology into new fields of application. Concentrated in one LED package, this offers two new areas of application: Signal functions requiring a high amount of flux to reach the photometrical requirements. Designs working with indirect lighting in order to create new styling variations. This paper will attempt to show the wide field of possibilities that can be opened up with new LED types, in combination with innovative optical systems.
Technical Paper

Tool Support for Analyzing and Optimization Methods in Early Brake System Sizing Phases

2000-03-06
2000-01-0442
The manufacturers of passenger cars increasingly assign development and production of complete subsystems to the supplying industry. A brake system supplier has to give predictions about system quality and performance long time before the first prototypical system is built or even before the supplier gets the order for system development. Nowadays, the usage of computer-aided system design and simulation is essential for that task. This article presents a tool designed to support the development process. A special focus will be on how to define quality. A formal definition of quality is provided, illustrated and motivated by two examples.
Technical Paper

Brake System with Double Link-Type Variable Ratio Brake Pedal

2000-03-06
2000-01-0438
In the past, in order to have good brake effectiveness, it was necessary to adopt high coefficient friction materials for pads or linings, or enlarged brake effective radii. But high coefficient material can create problems such as noise or vibration. And increasing effective radii is limited by the wheel package. A high pedal ratio can provide good effectiveness, but also leads to long pedal travel and poor brake feel. Specifically for trucks and SUV's with large GVW's, it can be difficult to achieve both good brake effectiveness and good pedal feel. In response to this difficult design challenge, a double link-type variable ratio pedal was developed for a production application.
Technical Paper

Complex Eigenvalue Analysis for Reducing Low Frequency Brake Squeal

2000-03-06
2000-01-0444
A front disc brake system is used as an example for an investigation of low frequency squeal. Many different modifications to this disc brake system have been proposed and this paper focuses on a solution that reduces the stiffness of the rotor. This is accomplished by a reduction in the Young's modulus of the rotor material. The complex eigenvalue method is used for a detailed analytical study in order to obtain a better understanding of this solution technique. Modal participation factors are calculated to examine the modal coupling mechanism. Parametric studies are also performed to find out the effects of friction coefficient and rotor stiffness. Results show that shifting rotor resonance frequencies may ecouple the modal interaction and eliminate dynamic instability, which is in agreement with experimental results.
Technical Paper

Development of a Single-Shoe Leading-Trailing Drum Brake—Code Named Fuchsia

2000-03-06
2000-01-0443
This paper describes a unique leading-trailing service drum brake design, code named Fuchsia, comprising a one-piece shoe and backing plate arrangement with an integral shoe platform. Because of the integral construction, Fuchsia offers a significant reduction in parts over the conventional drum brake design---it consolidates 16 standard components into one---resulting in a potential cost advantage over benchmarked products. It also offers benefits in performance stability, vibration resistance, low residual drag, low parasitic losses, and low operating threshold when compared to traditional designs. This paper gives an account of the key manufacturing processes, characteristics and performance testing of the brake and the incorporation of a extended-life lining configuration.
Technical Paper

The Transient Temperature Distribution in a Heavy Duty Brake System During Fatigue Crack Testing

2000-03-06
2000-01-0441
A transient numerical heat transfer model has been developed for the purpose of estimating the time-dependent temperature distribution in a heavy duty drum brake system. The model is based on a forward-difference explicit finite difference solution of the heat equation, in combination with a non-uniform pressure distribution for energy input, based on observed brake lining wear. Temperatures predicted by the model were compared to experimental dynamometer drum temperature measurements. The model was utilized to simulate a common industrial test for evaluation of brake drum resistance to thermo-mechanical fatigue cracking. Thermo-physical property variation and drum wall thickness were shown to exert a strong influence on the predicted temperature gradients and fatigue cracking susceptibility.
Technical Paper

Before and After Comparison of LRO and TV of Rotors After Low Temperature Gas Nitriding and Polymer Coat for Increased Corrosion Life

2000-03-06
2000-01-0446
Hayes Lemmerz has published in previous papers (Ref-1, 2 & 3), the method to low temperature nitride and polymer coat cast iron rotors to provide increased corrosion life, wear resistance and reduction in brake noise. We have, in this paper, investigated the two key dimensions of the rotor before and after the Nitriding Process. Low temperature (1050 degrees F) nitride finish machined rotors have to be handled in a special support fixture to prevent a change in thickness variation (TV) and lateral runout (LRO). Hayes Lemmerz has developed methods to keep LRO and TV in the print specification after the Nitriding and polymer coat process. The parts are made to extremely tight LRO and TV tolerances so that Nitriding done on such rotors, the dimensions of the rotors do not exceed print specification.
Technical Paper

An Analytical Method to Predict Thermal Distortion of a Brake Rotor

2000-03-06
2000-01-0445
The severe thermal distortion of a brake rotor can affect important brake system characteristics such as the system response and brake judder propensity. This paper will propose a technique to determine the thermal distortion under transient or steady state conditions. The technique involves utilizing a PC-based computer program to calculate the necessary thermal parameters and apply the results as input to a finite element-based thermal stress analysis. This unique approach provides a reliable methodology to determine the heat input and cooling characteristics of a given brake system in addition to resultant distortion and stress components within the brake rotor. Analysis results are also compared to measured temperature and distortion data.
Technical Paper

Reducing High Frequency Disc Brake Squeal by Pad Shape Optimization

2000-03-06
2000-01-0447
An analytical model based on finite element method and a modal coupling approach used for evaluating high frequency disc brake squeal is discussed. The model incorporates the pad-rotor mode locking effect, which is responsible for a good share of high frequency disc brake squeal problems. The application of the model in the optimization of pad shapes for several vehicle platforms are presented with good correlation to vehicle and dynamometer tests.
Technical Paper

Low Frequency Drum Brake Noise Investigation Using a 1/4 Vehicle Test Rig

2000-03-06
2000-01-0448
A test rig which replicates a one quarter vehicle of a rear wheel drive vehicle, including the suspension system, is used to investigate a low frequency noise. The cross beam is included along with the vehicle suspension spring which is loaded against a sprung loaded mechanism that represents the tyre stiffness exactly and supports the brake geometrically as the tyre would. Drive to the drum is from a DC motor through the wheel drive axle. Holographic Interferometry is used to observe the modes of vibration of the drum with mirrors strategically placed to observe additional features such as the backplate, spring pan and cross beam. Initial results show the mode of vibration of the backplate to be of a diametral mode order and to be moving in the direction of drum rotation. Additionally it is seen that the spring pan and cross beam exhibit high amplitudes of vibration.
Technical Paper

42V PowerNet in Door Applications

2000-03-06
2000-01-0450
This article describes the effects of a future 42V automotive electrical system on the vehicle electronics, focusing mainly on the consequences for power semiconductors and their associated technologies. Taking the example of a door module, it then shows how existing 14V loads can be operated on the 42V PowerNet and what advantages result for operation of adjusted 42V loads. The following different problem-solving approaches are presented for typical loads such as power windows, electrically positioned and heated outside mirrors, and central locking: Power windows: A test motor specially developed for the 42V supply is continuously operated directly from the electrical system using suitable power semiconductors. Central locking: A conventional 14V motor is operated at 42V, its operating point being set using pulse width modulation (PWM). Remaining door module: Smaller 14V mirror motors and the control electronics are supplied from a second 14V system.
Technical Paper

Innovative Electrical and Electronic Architecture for Vehicles With Dual Voltage Power Networks. In-Vehicle Application

2000-03-06
2000-01-0452
OEM's and car manufacturers suppliers have agreed to increase the electrical system operation voltage up to 42VDC -36VDC battery voltage- in order to save electricity and to enable near future vehicles, characterized by a high demand for power consumption, mainly because current mechanical operated systems - valves, air conditioning - are expected to be replaced by electrically powered systems. However, this transition towards a pure 42VDC network is going to be gradual, in a first step combining the current 14VDC -12VDC battery voltage -and the new 42VDC operating voltages, the so called “Dual Voltage architecture”. Electrical and Electronic Distribution Systems (EEDS) are the keystone of energy optimisation strategies that will successfully fulfil the new requirements and the following electrical systems' aspects must be taken into consideration for a Dual Voltage power network: protection, switching, conversion, control signal management and distribution.
Technical Paper

Approach to “System on Chip” of ABS/ECU -Using Mixed Signal ASIC and Method of Construction-

2000-03-06
2000-01-0449
1 ABS becomes popular standard equipment due to increased demand for vehicle safety from user. That trend requests to make ABS smaller in size and lower in cost. Electronic Control Unit of ABS (ABS/ECU) has to correspond to that request and, further, ABS/ECU should lead system development by integration of ECU with actuator in engine compartment. We have been promoting the above development positively as the developer of ECU. This paper describes the development of high temperature-proof and small sized ABS/ECU composed 2 chips with using ASIC (Application Specific of Integrated Circuit) design and the method of thermal design, suitable for integration with actuator.
Technical Paper

Development of a Vehicle Electric Power Simulator for Optimizing the Electric Charging System

2000-03-06
2000-01-0451
The electric power system of a modern vehicle has to supply enough electrical energy to numerous electrical and electronic systems. The electric power system of a vehicle consists of two major components: a generator and a battery. A detailed understanding of the characteristics of the electric power system, electrical load demands, and the driving environment such as road, season, and vehicle weight are required when the capacities of the generator and the battery are to be determined for a vehicle. In order to avoid the over/under design problem of the electric power system, an easy-to-use and inexpensive simulation program may be needed. In this study, a vehicle electric power simulator is developed. The simulator can be utilized to determine the optimized capacities of generators and batteries appropriately. To improve the flexibility and easy usage of the simulation program, the program is organized in modular structures, and is run on a PC.
Technical Paper

Experimental Sensitivity Studies on Glass Bonding Urethanes

2000-03-06
2000-01-0419
This paper investigates the sensitivities of glass bonding adhesives to the dynamic characteristics of automotive body structures. Experimental modal analysis was conducted to study the damping, response amplitude, and stiffness of different adhesives to a door assembly and a vehicle body. Three different glass bonding adhesives were used in this study. Performance advantages of using these adhesives are given.
Technical Paper

Advanced Material Technologies — A Key Factor for Ultimate Driving Performance

2000-03-06
2000-01-0418
This contribution illustrates the important role modern material technology plays in automobile development. Numerous examples chosen from body, suspension, and powertrain components show how low weight technologies, better comfort, and a high level of recyclability can be achieved by advanced material solutions. General trends in material development for automotive applications are pointed out. Examples shown are high strength steels for body-in-white, aluminum for suspension, and modern plastics for engine components. In addition, some ideas are given for potential future material technologies as a key factor in providing ultimate driving performance.
Technical Paper

Hydromechanical Deep-Drawing of Fuel Tanks

2000-03-06
2000-01-0415
Deep-drawing with hydraulic counter pressure presents numerous advantages compared to conventional deep-drawing. Hydromechanical deep-drawing is a capable process for producing complicated and tapered-shaped stamping parts as well as parts which require excellent surface quality, i.e. outer body panels. Due to the lower costs of dies as compared to those for conventional deep-drawing, hydromechanical deep-drawing for low volume production allows for cost-savings. By using a fuel tank consisting of an upper and a lower tray as a sample, this paper discusses the various possibilities of hydromechanical deep-drawing. The described die set has an integrated multi-point draw cushion which permits material flow control through optimized blankholder forces [Aus]. In addition, a new machine concept of a 35,000 kN press, which can be used for hydroforming of tubes, extrusions, and sheets, will be presented.
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