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2004 FISITA World Automotive Congress
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An Experimental Study on the Ball Screw Noise of Eps System

MANDO Corp.-Joo Namgung, Daijong Chung, Jaeyong Lee, Hegwon Jo
  • Technical Paper
  • 2004-05-0324
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Recently the automobile makers tend to adopt an EPS (Electric Power Steering) system which uses an Electric motor for automobile steering assist force in order to reduce the fuel consumption and the emission.Among the electric power steering, Rack assist type EPS (R-EPS) which assists a rack bar has been a noise problem from the ball screw mechanism. And it is founded that this noise is generated from the ball screw gear itself, in other words, there is an obvious limit to reduce the rate of noise. In this reason, it is true that many steering system manufacturers are trying to develop the modified R-EPS system that can reduce the noise by decreasing RPM of the ball nut and that does not use the ball screw mechanism.This paper describes the process of understanding a change of noise property (frequency) while noise being transmitted from the ball screw to the driver and an approximate noise delivery path by testing and analyzing a noise in several states (a ball screw assembly, a steering gear assembly and a vehicle…

Towards a Design and Optimization Methodology for Automotive Mechatronics

The Royal Institute of Technology-Fredrik Roos, Jan Wikander
  • Technical Paper
  • 2004-05-0159
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
The number of mechatronic sub-systems in road vehicles is growing fast. Auxiliary systems that traditionally have been driven by the combustion engine via, for instance, gears, belts or hydraulics are being replaced with electric systems. This development is primarily driven by new and improved functionality, but it is also necessary for the transition to electric and hybrid-electric drivetrains.A mechatronic sub-system can be very complex to design and especially to optimize, mainly due to the multi-domain characteristics of mechatronics. Usually, in traditional methodologies for mechatronic design, the mechanical structure is determined separate from the controller and also from the electric motor design. To improve the results from the mechatronic development process, a more holistic approach is necessary. The foreseen very large production volumes of mechatronic actuation modules for the automotive industry enable such a holistic approach, where all constituent components can be designed and optimized in one common process.The problem that is being approached in this research is delimited to a methodology for conceptual design and optimization of mechatronic actuation modules. Such modules will be the…

Data Acquisition and Control Equipment Embedded in the Vehicle

Applus IDIADA-Oscar Carrasco, Xavier Bertol¡
  • Technical Paper
  • 2004-05-0163
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
In recent years the volume and complexity of electronics in vehicles has increased spectacularly. New technologies such as multiplexed buses and GPS represent new challenges to the in-vehicle data acquisition systems traditionally used for testing purposes. This paper describes the tool that we developed to meet these challenges.The main objective was to have data acquisition equipment with some control features adapted to the requirements and complexity of the vehicles and testing programs that are currently carried out in our department.To meet these requirements we chose a laptop computer equipped with a special PCMCIA CAN bus interface, a GPS antenna, and a signal- conditioning module. Labview was chosen as control software.The resulting equipment can be used as a traditional datalogger for any of the different three inputs (CAN, GPS or DAQ), or as a "Cycle follower" making it possible to carry out and monitor "Speed/time" and "Speed/distance" cycles defined in advance by the user.

Development of a Design Tool for Brake Boosters Based on Continuous System Simulation

Instituto Tecnológico de Aragón (ITA)-Javier Orús, José Ramón Valdés, Isaac Nadal, José Luis Pelegay
TRW Automotive-Thomas Pütz, Manuel Giménez
  • Technical Paper
  • 2004-05-0086
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Brake actuation unit is the first component after the pedal in the brake system of a car. In this system, a helping force coming from the vacuum of the car engine is added, in a controlled way, to the force applied in the pedal by the driver. As in the rest of the automotive industry, shortening the design cycle for this component is critical and, then, the use of advanced simulation tools becomes necessary.The complexity of generating mathematical models to simulate the behavior of this system is the coupling of multiple physical domains (mechanics, electrical/electronic/magnetic, pneumatics and hydraulics) in a single component and the influence in the booster performance of the deformation and friction on rubber parts. The solution adopted to deal with these difficulties is the generation of dynamic models, using techniques of continuous system simulation, and combining them with results obtained from both computer fluid dynamics (CFD) on booster valve and finite elements analyses on elastomer components. With this methodology, accuracy in the results is highly improved with regard to using analytical approximations…

Driveshaft Design Guidelines for Optimized Axle Gear Mesh NVH Performance

American Axle & Manufacturing, Inc.-Zhaohui Sun, Michael Voight, Glen Steyer
  • Technical Paper
  • 2004-05-0467
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
This paper presents a study of the relationship between the driveshaft dynamics and vehicle axle system gear noise; and an analytical modelling approach developed by the authors that could be used to analyze and optimize the driveshaft dynamics to achieve minimized axle system gear noise. The mechanism of axle system noise and the effect of the driveshaft design are briefly overviewed and discussed through examples. Design criteria of the driveshaft configuration for optimized driveline NVH (Noise, Vibration and Harshness) performance are then presented. An analytical tool developed by the authors is presented, which provides an efficient way to analyze the driveshaft dynamics and its effects on gear system noise without the need of detailed CAD (Computer-Aided Design) models. The accuracy of the analytical approach is illustrated through examples of comparison with FEA (Finite Element Analysis) detailed model predictions as well as component and vehicle testing results. The capability and efficiency of the approach provide an advantage in the driveline system design, including quick sorting of a large group of driveshafts as well as obtaining design…

Investigation of the Influence of Manufacturing Tolerances on a Fully Variable Valve Train

INA-Schaeffler KG-Frank Himsel
Liverpool John Moores Univ.-Michael Gilmartin, Steven Douglas
  • Technical Paper
  • 2004-05-0090
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Different mechanisms for Continuously Variable Valve Lift (CVVL) have been proposed and patented and partially implemented in mass production. This paper briefly reviews the functional appeal of one solution called INA EcoValve.To the authors' knowledge very little attention has been paid to understand how manufacturing tolerances influence the overall functional behavior of high-speed mechanisms and in particular to continuously variable valve trains. Therefore the specific requirement arising from these kinds of valve trains are discussed. The shortcomings of traditional tolerance analysis methods are outlined and it is shown, that the inclusion of clearances and flexible parts is fundamental for the full understanding of the influence of tolerances on the valve train performance. A strategy is proposed that will allow the influence of tolerances on the dynamic behavior of the valve to be understood. Through this understanding optimal valve trains can be manufactured to meet both cost and performance objectives.

Detection of Ash and Particulate Distribution in Diesel Particulate Filters Through X-Ray Computed Tomography

Centro Ricerche FIAT S.C.p.A.-Sebastiano Lamacchia, Marco Federico Pidria, Paolo Faraldi, Silvio Corrias
  • Technical Paper
  • 2004-05-0391
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Nano-sized dusts (PM10 and PM2.5) are one of the prominent sources of pollution in the urban areas; Vehicle ICEs contribute to this pollution with particulate emission, and diesel engines in particular. For this reason, EU and US legislations are issuing restrictive limitations for particulate emissions. The diesel particulate emissions have then to be abated, by applying ceramic filters in the exhaust line. Nevertheless, a correct management strategy for such a device is extremely complicate, and moreover critical for engine proper operation. For this reason, the understanding of the soot and ash distribution inside the filters is mandatory. Industrial Computed Tomography is asserting as the best technology available on the market today for such purpose, being able to give detailed information on the soot/ash distribution patterns and even its relative concentration along the filters, without altering the functionality of the device, nor the distribution of the stored material.In this paper the analysis procedure and some significant results of the detection of ash and particulate distribution in diesel particulate filters through X-ray Computed Tomography is described.

Does Accident Analysis Convince Us to Develop Active Safety Systems?

Budapest University of Technology and Economics-Gábor Melegh, Dávid Lengyel
ThyssenKrupp Presta-István Wahl, István Jánosi
  • Technical Paper
  • 2004-05-0395
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
One of the most important wishes of the car manufacturer is to ensure that the new developed cars correspond to the expectations of the increasing traffic safety. Reaching this wish such active safety systems are necessary, which continuously appear in passenger cars for many years, on account of speedy developing electronics.Nowadays, in modern vehicles the active safety systems act into the brake system, engine, powertrain and the suspension operation in case of emergency. This possibility will be extended with steering interaction in the close future as well. However, the active safety systems work separately, prohibiting the advantage of integrated systems. Finding out which subsystems can work together in different driving conditions to avoid accident, a complete accident analysis has been achieved based on the Hungarian police, insurance companies and accident experts database as well. The analysis of the accident proves us to use and integrate active subsystems in several driving conditions.This paper introduces the result of the accident analysis, the investigation of using active safety systems alone or integrated in different driving conditions to avoid…

Model-Based Fault Detection for An Active Vehicle Suspension

DaimlerChrysler Research Center Frankfurt-Hans-Peter Schöner
Darmstadt University of Technology-Daniel Fischer, Rolf Isermann
  • Technical Paper
  • 2004-05-0054
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Automobiles show an increasing number of mechatronic developments by the integration of mechanic and electronic systems. In the case of vehicle suspension systems, this comprises the application of hydraulic, pneumatic and/or electric actuators with the aim of active roll and pitch stabilization and an increase of driving safety and comfort in general. Supplementary, the integration of these actuators and the involved sensors and electronic control units enables a detailed process supervision, fault detection and identification (FDI) for the whole system. This was developed for an active vehicle suspension system on a test rig.The inquired active suspension is a hydraulic fully loaded active suspension, whereat a hydraulic plunger is added in series with the conventional steel spring. This assembly is equivalent to the Active- Body-Control System of DaimlerChrysler. The test rig is equipped with suitable sensors for a series passenger car. The goal is to detect faults of all involved sensors with the distinction of noise, outliers, breakdown, and also offset and gain faults.One approach to solve FDI problems is to use parameter estimation and parity…

A Deeper Understanding of the Mechanisms Behind Brake Pulsation

Metaldyne Corp.-Mike Martyniak
  • Technical Paper
  • 2004-05-0235
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
Pulsation is often written about, often talked about and frequently found on vehicles. In the last few years, vehicle manufacturers have attempted to cure pulsation by reducing lateral runout (LRO) specifications on bearings, rotors and corners; they have reduced caliper slide forces; they have greatly increased the size of brakes while simultaneously reducing the coefficients of friction in linings to reduce wear rates. These and other changes have not worked entirely as planned and, in fact, have added a tremendous cost. One of the reasons for the lack of success has been the lack of a clear understanding of the mechanism behind pulsation. Using a cam and follower analogy, the author was able to derive a mathematical expression for pulsation. The rotor is analogous to the cam and the piston is analogous to the follower. Also, Harmonic Lateral Runout (HLRO) is defined. By integrating the two methods the author suggests that in many cases, only certain harmonics of LRO need to be controlled to prevent pulsation. With the mathematical expression, pulsation can be studied before…