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DaimlerChrysler and Mechadyne have undertaken a piece of work to investigate the opportunities for improving the operation of light duty diesel engines using variable valve timing. The very high compression ratios used in this type of engine make it essential to be able to alter the valve open periods to affect exhaust valve opening and intake valve closing, whilst leaving the valve motions largely unchanged around overlap top dead centre to avoid valve to piston contact. This paper presents an overview of the design solution, a description of the simulation model used, performance and economy data predicted by the model and a discussion of other areas of opportunity where improvements may be possible.

Commercial Heavy vehicles (CHVs) are an efficient and reliable link between marine, railroad, and air transportation nodes. The vehicle braking power imposes an important constraint in the allowable vehicle speed. The compression brake augments the vehicle retarding power and is currently typically used as an on-off device by experienced drivers. Hardware and software advances allow modulation of the compression brake power through variable valve timing, and thus, enable integration of the compression brake with service brakes. To analyze how much the compression brake affects vehicle speed during braking, we develop a crank angle engine model that describes the intrinsic transient interactions between individual cylinder intake and exhaust gas process, turbocharger dynamics, and vehicle dynamics during combustion and variable brake valve timing. The model is validated using experimental data.

The SI-engine has a disadvantage in fuel economy compared with a DI-Diesel engine. One of the major effects is the throttle-driven load control with its pumping losses. The main target is to reduce these losses in the thermodynamic process with a throttle-free load control. BMW has developed fully variable valve trains as a possible technical solution to realise a load control by regulating the valve lift and the closing time of the inlet valve. The essential variability can be achieved by fully variable mechanical valve trains or mechatronic systems both showing a robust running behavior in emissions and cyclic fluctuations. The camshaft driven mechanical system is based on the technology of the BMW Double-VANOS system. An additional variability makes it possible to shift the valve lift continuously in order to control the valve closing. The highest variability is given by a system with each valve being controlled seperatly.

The increasing complexity of automotive electronic systems can only be managed by a higher integration of the modules and a high reliability of the individual electronic devices. That means, the number of electronic components on board will decrease and their complexity will increase. This paper describes how to meet the requirements for the power supply of a 32-bit microcontroller based system in an automotive environment.

We have applied a non–linear control system to a hydraulically–operated continuous valve timing control (C–VTC) now in the mainstream of variable valve actuation systems. The system applied this time is a sliding mode control (SMC), which is found of late in a number of applications. Hydraulic pressure serving as the driving source of the C–VTC and the mechanism of the C–VTC have non–linear characteristics. We have investigated certain problems which occur, influenced by this non–linearity, when using a PID controller for C–VTC control. Typical issues include a large program memory size because of the large number of control parameters, a resultant considerable number of man–hours required for adaptation, and the low compatibility of response performance both for large step operations and for small step operations. Furthermore, high machining accuracy is required for the mechanical components.

Automotive manufacturers and Electronic Control Unit (ECU) vendors have been struggling with the challenges of providing calibration development capabilities in the mass production intent ECU's while keeping the cost of the mass production ECU's and associated tools to a minimum. Delphi Delco Electronics Systems has been working with Motorola Semiconductor and Infineon to add this capability into new microcontrollers to allow the ECU calibration variables to be monitored and calibration constants to be changed in real-time on the production intent ECU's. This technology has been successfully introduced to ECU customers and has demonstrated a significant savings in tool costs and assisted in improving the accuracy of calibration constant data values.

For basic research on the piston group a new simulation technique is developed using the contact algorithm of a commercial FE-code (MARC). Several improvements were made in order to adapt the MARC solver to the problem of sliding and dynamic contact. The first computations, a real transient analysis simulating the piston group, of both a two-stroke engine and a modern direct injected four-stroke Diesel engine for passenger cars, show that the new method is able to calculate the movements, velocities and accelerations of the piston. The quality of the results is mainly influenced by the hydrodynamic effects.

Today's requirements for engine management controllers are increasing in various aspects. Stronger emission standards and diagnosis requirements demand more complex control algorithms, faster system response times, better usage of sensor information throughout the system and higher accuracy of actuator stimuli. Despite that, new solutions are needed to answer the requirement for higher cost effectiveness, flexibility and reusability. The trade-off between cost and functionality is constantly being reviewed when choosing the right microcontroller to operate with an ECU. Integration of more complex and flexible functionality into the microcontroller helps to reduce the need for custom ASICs and thus reduce the overall system cost. In order to reduce the demands on CPU throughput within the microcontroller, manufacturers have introduced smart peripherals that off-load some of the work of the CPU into the peripherals.

The high temperature tribology issue for uncooled Low Heat Rejection (LHR) diesel engines where the cylinder liner piston ring interface exceeds temperatures of 225°C to 250°C has existed for decades. It is a problem that has persistently prohibited advances in non-watercooled LHR engine development. Though the problem is not specific to non-watercooled LHR diesel engines, it is the topic of this research study for the past two and one half years. In the late 1970s and throughout the 1980s, a tremendous amount of research had been placed upon the development of the LHR diesel engine. LHR engine finite element design and cycle simulation models had been generated. Many of these projected the cylinder liner piston ring top ring reversal (TRR) temperature to exceed 540°C[1]. In order for the LHR diesel to succeed, a tribological solution for these high TRR temperatures had to be developed.

It is estimated that in the United States, nearly one quarter of all fatal automobile accidents involve a vehicle rollover. [1] In order to reduce fatalities and serious injuries, it is desirable to develop a sensing system that can detect an imminent rollover condition with sufficient time to activate occupant safety protection devices. The goals of a Rollover Sensing Module (RSM) are; 1 To accurately estimate vehicle roll and pitch angles 2 To reliably predict in a timely manner an imminent rollover 3 To eliminate false activation of safety devices 4 To function properly during airborne conditions 5 To be as autonomous as possible, not requiring information from other vehicle subsystems.

Due to the increased flight envelope of GV aircraft and the industry-wide problems with crazing of structural acrylic transparencies, a re-design of the Gulfstream cabin windows was undertaken for the GV. The primary goals of this effort were to develop a cabin window that remained condensation free in all operating conditions, had improved service life, retained the size and shape of the classic Gulfstream cabin windows, and met all current FAA and JAA certification requirements. Cost and weight, as well as structural interchangeability with earlier Gulfstream aircraft, were also important issues. These goals were met during a significant design and testing effort undertaken both at Gulfstream and with the vendor, PPG Industries Inc. Aircraft Products. The resulting design, currently installed in all GV aircraft, retains the large field of view that is synonymous with all Gulfstream models while incorporating a number of newer technologies and improvements.

An analysis of vehicle tip stability in NHTSA Side Impact New Car Assessment Program (SINCAP) tests was conducted in order to better understand the causes of possible tip-over in such a test, and the potential relationship to occupant safety. Analyses were conducted of accident data involving light passenger vehicle rollovers. SINCAP tests conducted at several facilities with SUV-type vehicles were reviewed. A computer simulation model of the SINCAP test was developed and used to analyze the effects on vehicle tip-over of variations in vehicle and test facility parameters. It was found that fatal accidents involving “multi-vehicle rollover” (ie, SINCAP like conditions) were the least frequent among four accident types examined; and that SUV’s had the lowest fatality rate in such accidents, among the four vehicle types examined.

Any analysis tool should be validated to verify computation accuracy. Fatigue analysis processes are inherently complex to validate due to the sensitivity and interdependency of variables. In the current work the authors systematically separate the variables for independent evaluation and verification. The approach is the result of new Neuber notch analysis equations, derived by the authors, and draws upon the experience of the authors as well as several other analysts in developing an approach that reduces interaction between variables. The extension of the Neuber’s Rule into multiaxial format is presented. Each building block of the process is discussed: loads and load histories, stresses, stress concentrations, notch analyses (uniaxial and multiaxial), material properties (stress-strain response as well as life data), and damage accumulation. A method to account for fretting is discussed. Occasionally, during an evaluation, a variable is either overlooked or not quantified well.

This paper summarizes the results of a survey to estimate the market penetration rate of cockpit weather information systems in five aviation markets: transport, commuter, general aviation, business, and rotorcraft. It begins by describing the general features that survey respondents identified as necessary characteristics for the market success of cockpit weather systems. Next the paper analyzes the financial benefit of cockpit weather systems for each market segment. Decision reversal tables and Monte Carlo simulation are employed to examine the sensitivity of the financial results to changes in the cost and savings elements. Finally, estimates for adoption rates in the five aviation market segments are presented.

The current popularity of the Sport Utility Vehicle (SUV) market has led to new developments aiming to increase product performance. Such vehicles pose a significant challenge as they must perform to a high standard over a large variety of road conditions. Previously, emphasis has been placed on off-road ability. However, SUVs are now seen as an alternative to conventional luxury cars, and hence are expected to perform similarly, but without significantly degrading off-road performance. The introduction of a roll control system can achieve body roll levels lower than a conventional sports saloon, whilst improving off-road ability by removing the compromises associated with conventional anti-roll bars. This paper investigates the characteristics of such a system by developing a computer simulation of the vehicle and the associated roll control scheme.

The Transverse Leaf suspension with Superior Roll Axis is a new suspension concept for automobiles. It enables the load transfer during a turn to be more evenly redistributed between the two wheels on the same axle thus optimizing its tires lateral force capabilities. The TLSRA concept is made up of a single transverse leaf spring linking the middle of the sprung mass to the outer end of 2 transverse suspension arms per axle. Those transverse arms are mounted close to the middle of the sprung mass with their attachment points located above the mass centroïd. Each wheel assembly is mounted directly onto the free end of its respective suspension arm. Because body roll is now counteracting vertical load transfer during transient and permanent operating conditions, this suspension enables designers to keep spring stiffness low without compromising road handling.

The development of tires traction models is very important for tire mechanics and automobile dynamics. Based on principle of thermal balance and theory of frictional melting, a new method for determining tire traction on an iced highway was presented. It was shown that the computed results could compare with the available test results. The advantages of a car with CTI-DS travelling on ice or compact snow were demonstrated in theory and in experiment. It was recommended that an automobile be operating at lower inflation pressures to increase tire traction force on the above highways.

A friction induced rollover event generally comprises successive stages of control loss, lift-off, transition from lift-off to launch, and roll to rest. This transition is, of course, not instantaneous due to vehicle inertia. It is analyzed by numerical integration of the equations of motion to determine roll angle and time to launch, plus roll velocity at launch, as well as intermediate values of roll angle, roll velocity and surface force versus time. Representative curves and launch values are presented. The time to launch, which is several times greater than typical vehicle collision contact time, is seen to be dependent on the magnitude of surface friction; while roll angle from over-center at launch and roll velocity at launch do not vary substantially with changes in vehicle and surface conditions. It is also seen that the surface force initially rises above static weight, producing lateral force greater than the friction coefficient times vehicle weight as rotation progresses.

A single vehicle on-road rollover accident of a small van is used to examine the effectiveness of the Anti-Rollover Braking System (ARB). The circumstances of the accident are reviewed, and how the accident was modeled using ADAMS. ARB is then added to the vehicle model to examine what would happen if ARB had been on the vehicle. Two cases are examined. One case uses the same steering as in the accident, and one case uses the same path as the accident. In both of these cases, ARB would have prevented the vehicle from rolling over.

During the past few years, the National Highway Traffic Safety Administration's (NHTSA) Vehicle Research and Test Center has generated a plethora of reliable vehicle test data during their efforts to study vehicle rollover propensity. This paper provides further analyses of a small selection of some of the data. The analyses provided here derive in part from the previous work, trying to answer some of the questions spawned by earlier analyses. The purpose of this paper is to introduce several new concepts to the study of vehicle roll stability and provide case studies using the results available from the NHTSA testing. Results from several severe maneuvers are studied in detail to gain understanding of vehicle response in these cases.