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Extended Target Weighing Approach - Estimation of Technological Uncertainties of Concept Ideas in Product Development Processes

Karlsruhe Institute of Technology (KIT)-Albert Albers, Sven Revfi, Markus Spadinger
Published 2018-05-30 by SAE International in United States
The “Extended Target Weighing Approach” (ETWA) presented here describes a holistic, cross-subsystem, function-based lightweight design method - in terms of conceptual lightweight design - for the identification and evaluation of lightweight design potentials in the concept phase of product development. It systematically extends the existing “Target Weighing Approach” (TWA), in order to balance key factors mass, costs and CO2 emissions. During the application of the method, concept ideas are generated which have to be evaluated with regard to their potential.The selection of concept alternatives to be pursued in the early phase of product development often depends on the experience of the product developer. Therefore, the potential of some concepts is not recognized correctly or the risk according to the intended solution caused by missing knowledge or uncertainties is misjudged. This paper presents a method for the evaluation of technological uncertainties of concept ideas based on the PGE - Product Generation Engineering. Four factors - Impact, Carryover Variation Share, Reference Product - Technology and Reference Product - Application Scenario - to assess the total technological uncertainty…
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Method for Measuring and Analyzing Transient Powertrain Vibrations of Hybrid Electric Vehicles on an Acoustic Roller Test Bench

IPEK at KIT Karlsruhe-Albert Albers, Fabian Schille, Matthias Behrendt
Published 2016-06-15 by SAE International in United States
In terms of customer requirements, driving comfort is an important evaluation criterion. Regarding hybrid electric vehicles (HEVs), maneuver-based measurements are necessary to analyze this comfort characteristic [1]. Such measurements can be performed on acoustic roller test benches, yielding time efficient and reproducible results. Due to full hybrid vehicles’ various operation modes, new noise and vibration phenomena can occur. The Noise Vibration Harshness (NVH) performance of such vehicles can be influenced by transient powertrain vibrations e.g. by the starting and stopping of the internal combustion engine in different driving conditions.The paper at hand shows a methodical procedure to measure and analyze the NVH of HEVs in different driving conditions. In order to investigate the influence of noise and vibrations by restarting and stopping the internal combustion engine (ICE) (like switching between electric and hybrid driving or the start-stop function) on the driver, acoustic and vibration measurements are performed inside the vehicle. A binaural artificial head is used to examine the acoustic effects on the vehicle interior noise. The vibration behavior is analyzed using acceleration sensors at…
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Methods for Measuring, Analyzing and Predicting the Dynamic Torque of an Electric Drive Used in an Automotive Drivetrain

SAE International Journal of Alternative Powertrains

Daimler AG-Dirk Lieske
IPEK-Albert Albers, Jan Fischer, Matthias Behrendt
  • Journal Article
  • 2015-01-2363
Published 2015-06-15 by SAE International in United States
The driving comfort is an important factor for buying decisions. For the interior noise of battery electric vehicles (BEV) high frequency tonal orders are characteristic. They can for example be caused by the gearbox or the electric drive and strongly influence the perception and rating of the interior noise by the customer.In this contribution methods for measuring, analyzing and predicting the excitation by the dynamic torque of the electric drive are presented. The dynamic torque of the electric drive up to 3.5 kHz is measured on a component test bench with the help of high frequency, high precision torque transducer. The analysis of the results for the order of interest shows a good correlation with the acoustic measurements inside the corresponding vehicle. In addition an experimental and numerical modal analysis of the rotor of the electric drive are performed. The torsional resonance modes are put into context of the elevation of the dynamic torque with regard to the frequency. In a further analysis the phase shifts of the torsional excitation of the different rotor segments,…
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Maneuver-Based Analysis of Starting-Systems and Starting-Strategies for the Internal Combustion Engine in Full Hybrid Electric Vehicles

SAE International Journal of Alternative Powertrains

BMW Group-Heidelinde Holzer, Wolfram Bohne
IPEK - Inst. of Product Engineering, KIT-Albert Albers, Kevin Matros, Matthias Behrendt, Johannes Henschel
  • Journal Article
  • 2014-01-2901
Published 2014-10-13 by SAE International in United States
The requirement of the start of the internal combustion engine (ICE) not only at vehicle standstill is new for full hybrid electric vehicles in comparison to conventional vehicles. However, the customer will not accept any deterioration with respect to dynamics and comfort. ICE-starting-systems and -strategies have to be designed to meet those demands.Within this research, a method was developed which allows a reproducible maneuver-based analysis of ICE-starts. In the first step, a maneuver catalogue including a customer-oriented maneuver program with appropriate analysis criteria was defined. Afterwards, the maneuvers were implemented and verified in a special test bench environment. Based on the method, two sample hybrid vehicles were benchmarked according to the maneuver catalogue.The benchmarking results demonstrate important dependencies between the criteria-based assessment of ICE-starts and the embedded ICE-starting-system and -strategy. Those findings led to recommendations regarding the selection of suitable starting-systems and the design of the starting-strategy.
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Approach for Parameter Determination for Objective Comfort Evaluation of the Vehicle Vibration Induced by Powertrain

Daimler AG-Rui Cai, Rainer Spengler, Christian Olfens
Karlsruhe Institute of Technology-Albert Albers, Matthias Behrendt
Published 2014-06-30 by SAE International in United States
The driving comfort influences the customer purchase decision; hence it is an important aspect for the vehicle development. To better quantify the comfort level and reduce the experiment costs in the development process, the subjective comfort assessment by test drivers is nowadays more and more replaced by the objective comfort evaluation. Hereby the vibration comfort is described by scalar objective characteristic parameters that correlate with the subjective assessments. The correlation analysis requires the assessments and measurements at different vehicle vibration. To determine the objective parameters regarding the powertrain excitations, most experiments in the previous studies were carried out in several test vehicles with different powertrain units. Due to the different features among test vehicles, the subjective assessments and the objective measurements are influenced by further interfering factors, such as different wheel excitations between vehicles, which lead to an inevitable variance.This paper presents a new approach for determination of the objective parameters for vehicle vibrations caused by powertrain. This approach is performed in a real vehicle on the vehicle roller test bench. By using various measures…
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Method for Measuring and Analyzing the Transfer Path of Acoustic Phenomena into the Driver Cabin of a Battery Electric Vehicle

SAE International Journal of Engines

IPEK - Institut für Produktentwicklung-Albert Albers, Jan Fischer, David Landes, Matthias Behrendt
  • Journal Article
  • 2014-01-2071
Published 2014-06-30 by SAE International in United States
The driving comfort is an important factor for buying decisions. Especially for battery electric vehicles (BEV) the acoustic quality is an elementary distinguishing feature, since the masking of an internal combustion engine (ICE) is no longer present. Opposing the importance of the acoustic quality is the lack of knowledge of how to measure and interpret the high frequency noise generated by an electric powertrain with respect to the NVH behavior influencing the passengers [1, 2].In this contribution a method for measuring and interpreting the transfer path of acoustic phenomena from the drivetrain of a battery electric vehicle into the passenger cabin is presented. Due to the lack of masking by the ICE in case of BEV, high frequency phenomena must be considered as well.In order to determine the airborne transfer function from the electric powertrain to the driver cabin, a dodecahedral speaker is used for reciprocal measurements. Therefore in a first step, the sound power and the emission characteristic of the dodecahedron is investigated in a novel approach by laser scanning vibrometry and by measurements…
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A Method for Developing Specific Reference Cycles or Alternatively Test Cases for Commercial Vehicles and Their Auxiliary Systems

SAE International Journal of Commercial Vehicles

IPEK - Institute of Product Engineering-Friedrich Philipp Brezger, Albert Albers
  • Journal Article
  • 2012-01-2026
Published 2012-09-24 by SAE International in United States
In contrast to passenger cars, commercial vehicles exist in many layouts for different customer applications. The Daimler AG provides with their Mercedes Benz Trucks a product portfolio of 6 commercial vehicles (Econic, Atego, Axor, Actros, Zetros, Unimog), which are available in a multiplicity of model variants.Therefore, the well-known driving cycles of passenger cars such as NEDC (Europe), the 10-15 mode (Japan), the FTP & FTP75 (USA) and others cannot be used in regard to fuel consumption or dimensioning of a commercial vehicle [1, 6, 15]. A diversification of type and usage of the commercial vehicles is obligatory necessary, as already shown in publications of Holloh et al. [10]However, this paper offers a method which uses collected data from customers, in order to develop objective reference cycles or test cases. This described method can be equally used for both, creating the reference cycles of commercial vehicles mentioned above, as well as passenger cars. Especially when moving on to the more complex operating strategies and operating points or vehicles with many different auxiliary systems, this method is…
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Influence of Low-Frequency Powertrain-Vibrations on Driveability-Assessments

AVL LIST GmbH-Josef Zehetner, Klaus Meitz
Karlsruhe Inst. of Technology-Albert Albers, Christian Zingel
Published 2010-06-09 by SAE International in United States
Cost- and time-efficient vehicle development is increasingly depending on the usage of adequate software tools to enhance effectiveness. The aim is a continuous integration of simulation tools and test environments within the vehicle development process in order to save time and costs.This paper introduces a procedure to reveal the cause of low-frequency powertrain vibrations and the influences on the dynamic behavior of a vehicle on a roller test bench. The affected longitudinal acceleration signal is an arbitrative criterion for the driveability assessment with AVL-DRIVE™, a well-known driveability analysis and development tool for the objective assessment concerning NVH and driveability aspects of full vehicles. These experimental studies are embedded into an approach, which describes the functional assembly of three applied test environments "road," "roller test bench" and "simulation" with according tools in order to facilitate an integrated driveability development process.The low powertrain vibrations are identified by performance of positive load-change maneuvers (Tip-In) in the vehicle on a roller test bench. A parallel recording of acceleration signals by the driveability analysis sensor system and of defined surfaces…
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Driver Start-Up Comfort Rating of Automated Clutch Systems~An Objectification Using Artificial Neural Networks

University of Karlsruhe (TH)-Albert Albers, Marc Albrecht
  • Technical Paper
  • 2004-05-0309
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
During the product development process, dynamic features of vehicles are determined in drive tests. However, the evaluation of comfort behavior - either by engineers or by customers - can only be done at a later stage, because this requires a prototype close to the final product. Today's product development in automotive industries has moved more and more towards a virtual product development and tests have been shifted form "road to rig." Therefore, the prediction of comfort features from test-bench data and numerical simulation data is a great challenge and finding correlations between driver rating and data measured in drive tests is an important objective.The subject of the presented study is the start-up process, i.e., the process of starting to drive from standstill and the following acceleration process. Drive tests were performed both by experts in vehicle evaluation and also amateurs representing average consumers. As the test vehicle, an intermediate-class car with an automated clutch system is used. The start-up characteristics can thereby be set to different variants by applying different types of controller software. Characteristic…

Increasing the Performance of Motor Vehicle Clutches By the Use of Ceramic and the Resulting Effects on System Design

University Karlsruhe (TH)-Albert Albers, Asli Arslan
  • Technical Paper
  • 2004-05-0158
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
The experimental and constructive results illustrate that engineering-ceramic materials have a high potential in the field of dry running friction systems. According to first estimations, it is possible to build the vehicle clutch 53% smaller or to transmit up to 180% higher torque at the same size by an appropriate selection of the system friction pairing and a ceramic adequate design. The friction coefficient characteristic (decreasing friction coefficient above sliding speed) is unfavorable with regard to comfort (self-induced grab oscillations) of the vehicle clutch. Counteractive measures are developed in further research projects by barrier layer modifications of the ceramic surface on a clutch system. Furthermore, it is important to select the test procedure of the experimental analyses as close to the system as possible in order to obtain exact information concerning the target system.