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2024 Stuttgart International Symposium on Automotive and Engine Technology

Teil 2

Editors: André Casal Kulzer, Hans-Christian Reuss, Andreas Wagner

Publisher: Springer Fachmedien Wiesbaden

Book Series : Proceedings

Part of: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

Table of Contents

About this book

In einer sich rasant verändernden Welt sieht sich die Automobilindustrie fast täglich mit neuen Herausforderungen konfrontiert: Der problematischer werdende Ruf des Dieselmotors, verunsicherte Verbraucher durch die in der Berichterstattung vermischte Thematik der Stickoxid- und Feinstaubemissionen, zunehmende Konkurrenz bei Elektroantrieben durch neue Wettbewerber, die immer schwieriger werdende öffentlichkeitswirksame Darstellung, dass ein großer Unterschied zwischen Prototypen, Kleinserien und einer wirklichen Großserienproduktion besteht. Dazu kommen noch die Fragen, wann die mit viel finanziellem Einsatz entwickelten alternativen Antriebsformen tatsächlich einen Return of Invest erbringen, wer die notwendige Ladeinfrastruktur für eine Massenmarkttauglichkeit der Elektromobilität bauen und finanzieren wird und wie sich das alles auf die Arbeitsplätze auswirken wird. Für die Automobilindustrie ist es jetzt wichtiger denn je, sich den Herausforderungen aktiv zu stellen und innovative Lösungen unter Beibehaltung des hohen Qualitätsanspruchs der OEMs in Serie zu bringen. Die Hauptthemen sind hierbei, die Elektromobilität mit höheren Energiedichten und niedrigeren Kosten der Batterien voranzutreiben und eine wirklich ausreichende standardisierte und zukunftssichere Ladeinfrastruktur darzustellen, aber auch den Entwicklungspfad zum schadstofffreien und CO2-neutralen Verbrennungsmotor konsequent weiter zu gehen. Auch das automatisierte Fahren kann hier hilfreich sein, weil das Fahrzeugverhalten dann – im wahrsten Sinne des Wortes - kalkulierbarer wird. Dabei ist es für die etablierten Automobilhersteller strukturell nicht immer einfach, mit der rasanten Veränderungsgeschwindigkeit mitzuhalten. Hier haben Start-ups einen großen Vorteil: Ihre Organisationsstruktur erlaubt es, frische, unkonventionelle Ideen zügig umzusetzen und sehr flexibel zu reagieren. Schon heute werden Start-ups gezielt gefördert, um neue Lösungen im Bereich von Komfort, Sicherheit, Effizienz undneuen Kundenschnittstellen zu finden. Neue Lösungsansätze, gepaart mit Investitionskraft und Erfahrungen, bieten neue Chancen auf dem Weg der Elektromobilität, der Zukunft des Verbrennungsmotors und ganz allgemein für das Auto der Zukunft.

Frontmatter

E/E Architecture

Frontmatter

Intelligent Sensors in Dynamically Reconfigurable Automotive Architectures: A Proof of Concept

Zusammenfassung

The necessity of a reconfigurable software-defined vehicle platform that is no longer sold as a one-off, but can be continuously adapted to dynamic customer requirements during its lifetime, is becoming increasingly clear. Political and economic institutions have become aware of these needs and initiated actions in the context of contested markets with declining sales figures. However, according to our research, existing vehicle architecture concepts and frameworks do not cover the upgradeability, dynamic reconfigurability at runtime and continuous adaptability aspects of vehicle sensors to the necessary extent. Vehicle sensor technology constitutes the fundamental basis for safe decisions of autonomous driving functions, we therefore consider the importance of this topic to be significant. Building upon the existing service-oriented E/E architecture framework ROSMARIN, we want to contribute a concept extension, allowing the seamless integration of intelligent sensors in vehicles. In addition to requirements for intelligent sensor technology in flexible architectures such as Plug-and-Play of sensor hardware, upgradeability through virtualization of sensor software and runtime resilience, our concept furthermore integrates a novel generalized approach for dynamic sensor calibration and fusion. We prove our concept on a physical demonstrator setup with ultrasonic, LiDAR and camera sensors and demonstrate the upgradeability and reconfigurability of sensor hardware and software. In addition, we show the dynamic online fusion of camera and LiDAR data with minimal effort, while also proving the resilience and automatic adaptability of our approach in case of unforeseeable events like sensor failures.

Lennard Hettich, Michael Weyrich

Electric Powertrain

Frontmatter

High-Fidelity Modular Modeling of Electric Vehicle Drive Unit Components for System Optimization

Abstract

Optimizing the design and topology of electric drive units regarding performance, efficiency and weight has become an integral part in the early phase of vehicle design. Present approaches sacrifice either computational speed or precise physical behavior in their component models.

To overcome this, a computationally inexpensive, high-fidelity approach is proposed, that surrounds a neural network model of the electric machine with an analytical inverter model and an interpolation model for the transmission. All three models share the common feature: Their inputs are parameters describing the geometry, materials, or electric design of the component, in order to maintain a link between the components design and its properties. The outputs of the models are maps and curves of their efficiency and performance, which can be combined in a modular way to account for interactions between the components e.g., shifted load points in the machine due to variations in the transmission ratio or the inverter switching frequency. For the electric machine that is facilitated by multiple linked neural networks, predicting scalar properties, the torque-speed curve and loss maps. The entire model is compared with present approaches and assessed regarding its accuracy, its training requirements and its limitations. Finally, the computational performance and the improvement in design of the approach is evaluated in an exemplary optimization of a drive unit.

Christian Könen, Tobias Engelhardt, Dr.-Ing.Hans-Christian Reuss

Fuel Cell

Frontmatter

Ion Exchanger for Fuel Cell Coolant Loop: Optimization of Product Service Life

Abstract

Fuel cells will play an important role in reducing CO₂ emissions from transport, especially for heavy duty use cases. Current fuel cell systems have an electrical efficiency of ~50 %. The remaining 50 % of energy lead to heat generation, which must be removed by the coolant loop at very high flow rate. In order to ensure a robust running system and to avoid electric shorts, the electrical conductivity in the fuel cell stack has to be kept low. By using the ion exchange technology, contaminants such as ions released by several components in the coolant loop and degradation products of the coolant, are separated. The core component of such an ion exchanger is the ion exchange resin. The product service life can be significantly extended by selecting a suitable ion exchange resin and a suitable design. Therefore, this paper describes the key aspects of the product lifetime such as the contamination occurring, the ageing mechanisms of the resin and the product design. In addition, a modular design concept of an ion exchanger for fuel cell systems >200 kW is presented.

Simon Leininger, Andreas Wildermuth, Maximilian Süß

FVV e.V. Science for a moving society

Frontmatter

DIH2jet (DI Hydrogen Combustion Process)

Abstract

Hydrogen combustion engines are a viable solution for defossilizing mobility, mainly discussed in the heavy-duty sector. Conventional applications of hydrogen combustion in Internal Combustion Engines employ port or direct fuel injection with lean premixed, spark-ignited combustion strategies, which significantly lower engine-out NO_X emissions and try to avoid abnormal combustion events at the price of low power density. This study aims to tackle the challenge of the demanding boost pressure requirements in lean conditions using a non-premixed jet-guided strategy at stoichiometric conditions, omitting the related risk for abnormal combustion. Results from a single-cylinder engine comparing stoichiometric and lean homogeneous operation to three jet-guided or stratified modes applying different delays between start of injection and ignition are presented, supported by findings from an optically accessible Rapid Compression Expansion Machine. The experiments reveal an advantage in engine-out NO_X emissions for globally stoichiometric operation in jet-guided mode compared to homogeneous operation resulting in similar levels of indicated efficiency depending on the ignition timing. Early ignition of the jet shows potential for stable mixture-controlled combustion in combination with dedicated hydrogen injectors with higher mass flow rates.

Anne Beyer, Michelangelo Balmelli, Laura Merotto, Yuri M. Wright, Patrik Soltic, André Casal Kulzer

Degradation Model of Hairpin Winding in Inverter-fed Motors Considering Thermal and Electrical Stress

Abstract

This paper presents the findings of a study on the degradation of hairpin winding insulation. Hairpins are commonly used in inverter-fed motors in electrical vehicles. In order to achieve an ageing or lifetime model, the geometry and the electric field stress inside a stator-slot of an electric motor was analyzed and a suitable test setup was developed. A group of hairpin-in-slot specimens have been subjected to superimposed thermal and electrical load conditions at pulse-width modulated (PWM) voltage. The levels of stress on the hairpin windings have been defined based upon Design of Experiments (DoE) principles. The tests have been performed in several stages, taking into account that the physics of failure are unknown. In order to get the data for the lifetime analysis, partial discharge (PD) measurements were used. PD inception voltage (PDIV) and PD extinction voltage (PDEV) were recorded during aging tests. Based on the data from the PD measurements, several degradation path models were fitted and compared. From the varied stress levels, the parameter influence on the degradation rate was evaluated. Based upon the plausibility of the found results, the validity of the obtained degradation model was assessed.

Chuxuan He, Philipp Mell, Michael Beltle, Martin Dazer, Stefan Tenbohlen

Hydrogen

Frontmatter

Advancing Internal Combustion Engines and Fuel Innovation: A Modular Approach to 3D Virtual Prototyping for a Carbon-Neutral Future

Abstract

The upcoming automotive emission regulations require a rapid transition to near-zero emission vehicles, making it increasingly necessary to understand which type of carbon-neutral fuel best suits each internal combustion engine (ICE) application and vice versa. Given the high costs associated with the development of ICE layouts, components, and fuels, leveraging 3D-CFD simulations assumes an essential role as a screening tool preceding the prototyping phase. Intending to reduce computational time while extending the simulated domain to the entire engine (including a 0D or 3D turbocharger model), FKFS devised QuickSim, an innovative 3D-CFD tool for virtual engine development. Thanks to a combination of in-house numerical models for injectors, fuels, and combustion processes, this 3D-CFD software meets the requirements of a rapid and pragmatic virtual approach to drive the industrial evolution of future engines. This paper presents QuickSim as the cornerstone of a robust methodology for the simulation of a comprehensive engine domain, showcasing its efficacy in designing and optimizing engine layouts, characterizing individual components, and exploring fuel solutions to optimize combustion efficiency and emission reduction. The effectiveness of this approach was proved through several examples drawn from production and motorsports engine applications. Here, the impact of several fuels (hydrogen, methanol, synthetic, and biofuels) on different engine geometries was analyzed in conjunction with different injection and ignition systems, including active and passive pre-chambers. These preliminary studies highlight the modularity of QuickSim, enabling the systematic exploration of optimal fuel and engine layout combinations to maximize the stated efficiency.

Marco Chiodi, Cristian Tortorella, Esteban Hernandez Haro, Mario Pipolo

Experimental Toolchain for Evaluation of Mixture Formation and Combustion in Hydrogen Engines for Light Duty Applications

Zusammenfassung

The present publication focuses on the optimization of mixture formation and combustion in a low-pressure direct injection hydrogen engine for passenger cars and light commercial vehicles.

In a first step, the H\(_2\) jet properties are investigated in an optical vessel. Schlieren optics are used to track the gas jet’s evolution and to identify relevant physical phenomena. To go beyond a purely descriptive analysis and understand the root causes of the observed behavior, laser induced fluorescence and particle image velocimetry are optimized to capture effects specific to gas jets such as supersonic shock structures and are used to supplement the schlieren data.

High speed video endoscopy (HSVE) is adapted to H\(_2\) combustion in a next step, taking into account that the flame becomes visible mainly due to thermal radiation of hot water vapor. The usefulness of HSVE is highlighted by measurements in which mechanisms leading to irregular combustion events are recognized.

Finally, thermodynamic analysis of the engine process concludes the investigations. The effects of late H\(_2\) injection on engine efficiency and engine-out exhaust emissions are discussed. When the H\(_2\) jet propagates mainly along the roof of the combustion chamber and reaches the open intake valves—an effect identified and understood due to the optical investigations—a change of exhaust gas composition is observed. Engine test bench measurements demonstrate that these changes can be taken advantage of using variable valve timings.

David Lejsek, Dimitri Seboldt, Philippe Leick, Roman Grzeszik, Michael Frank, Karl Georg Stapf

Development of a High-performance Hydrogen Engine

Abstract

In addition to battery EV and fuel cell, the H₂ engine is establishing itself as an alternative drive option for climate-neutral mobility. Bosch is already developing series components for H₂ engines with a focus on commercial vehicle and off-highway applications. The favorable properties of hydrogen also open up potential for powerful engines in sports and race cars, the DNA of Bosch Engineering.

In order to make this potential tangible, experts from Bosch Engineering and Ligier Automotive have set up a high-performance vehicle with a 3.0-l V6 H₂ engine in a joint innovation project in only a few months.

The requirements for safe H₂ operation in a high-performance and high-speed concept were derived and integrated into the vehicle (storage system, operating strategies, software, etc.).

For the integration of the hydrogen storage system, the entire carbon monocoque chassis was newly developed. Special attention was paid to the multi-stage security concept.

The presentation shows the engineering challenges in the comprehensive adaptation of the combustion engine and its integration into the entire vehicle including hydrogen storage. With more than 3,000 kilometers on test tracks in Germany and France, the project shows new perspectives and the potential for a climate-neutral sports and race car drive. The demonstrator confirms the applicability of this technology in a racing series such as the 24 Hours of Le Mans.

Stephan Tafel, Lionel Martin

New Horizons of Cylinder Mixture Formation in Direct Injection Hydrogen Combustion Engines

Abstract

First hydrogen combustion engines will most likely go into series with port-fuel injection, based on Diesel engine hardware. But it is already obvious that direct injection concepts will represent the second generation of mixture formation systems. Challenges like injection nozzle design and mixture formation for highest levels of homogeneity are already well known. Market participants are improving these kind of product properties.

This paper discusses several additional opportunities aiming to increase the homogeneity index of direct injection concepts allowing in consequence lower NO_X and/or higher torque output at the borderline of an air-to-fuel ratio of approximately 2.5.

The new Schaeffler Dual Mode nozzle provides first results in terms of homogeneity using both flow patterns, Coandă and a straight jet, during the same engine working cycle. The Coandă fuel mass share can be varied by parameters like pressure ratios, needle lift and Coandă radius leading to a current reduction of engine out NO_X Emissions of 30–40%.

Olaf Weber, Jan Leberwurst, rer.nat.Jochen Broz, Patrick Ullmann

Mobility Concepts

Frontmatter

Commercial Vehicle Concepts Opportunities for New Developments in the Interplay of Drive Technologies, Infrastructures and Logistical Requirements

Abstract

Commercial vehicle architectures are manufactured and offered in mass production. The opportunities for a reorientation arise in consideration of new drive and body technologies with ecological and economic aspects for low-volume commercial vehicles

Jürgen Erhardt

LiMo 2030 Sustainable urban Living and Mobility Concept

Abstract

Car parks are increasingly competing with living space and green areas. Due to climate change and the associated heating of urban areas, green spaces (with shade-giving deciduous trees) are becoming essential for survival. LiMo aims to combine living and mobility in a practical, cost-effective and sustainable way—with a vehicle concept that (virtually) no longer needs a parking space. How can this work? When a vehicle is no longer in use, it has to be parked somewhere. The trick as to why it still works is the modular design of the vehicle cabin and chassis. The LiMo concept developed at Esslingen University of Applied Sciences consists of a multifunctional cabin that can not only be integrated into different transport systems (road, rail, elevated railway, cable car), but also offers a significant additional benefit in conjunction with the building, namely a living space extension that can be used like a mini conservatory. If you want to be individually mobile, you can use an app to book a chassis that comes along autonomously and waits until the cabin and its occupants travel downwards via a sophisticated rail system, dock and head for the desired destination. LiMo combines the advantages of a private car (its own passenger compartment) with the traffic-related benefits of car sharing—all of which is convenient (barrier-free), sustainable (parking spaces become green spaces) and cost-effective (no underground car parks required).

Hugo Gabele, Tsz Yeung Tai, Tobias Langlois, Martin Grözinger, Felix Paukner

Software Defined Vehicle

Frontmatter

Faster Software Development Cycles using Graph-based Code Similarity Analysis

Zusammenfassung

As the technology in cars continues to evolve, the development is faced with increasingly complex software solutions. Tasks such as maintenance over the lifespan of the vehicle, reuse in other models as well as compliance with regulatory requirements, therefore, need to be efficiently accomplished to keep up with ever shortening development cycles. In the context of the research project SmartDelta (sponsored by the Federal Ministry of Education and Research on the basis of a decision by the German Bundestag via ITEA4), we are developing a tool for code-based similarity analysis. This enables us to obtain automated code reuse suggestions, which makes code changes such as fixing vulnerabilities over multiple product variants faster. Combined with test case prioritization, it will significantly decrease time needed for testing. By taking advantage of the collaboration possibilities within the project, our solution is created with large, production scale codebases in mind. Our approach is based on Code Property Graphs which provide a compact yet comprehensive model on the code. We employ classical algorithms in conjunction with machine learning to extract the desired information out of Code Property Graphs.

Emanuel Ramneantu, Tino Strehl, Jens Grobe, Marlou Gijzen, Stephan Helfrich, Arijit Mallick, Victor Fäßler

Integrated Approach for High-quality Software Development of Upgradeable Vehicles

Zusammenfassung

The automotive industry’s pursuit of customization poses safety challenges for future vehicles due to the limitations of current development practices. Although updating existing driving functions over the air is already possible, the large number of vehicle variants and installed hardware components prevents manufacturers from upgrading existing vehicles and integrating new driving functions and enhancements.

This paper presents an integrated approach for high-quality software development of upgradeable vehicles to increase the reliability and safety of updates. Our approach transfers current software product line development methods to the system generation engineering of vehicles to enable predictive development and expansion of software-defined driving functions, considering hardware adaptations based on expected changes in product profiles. We define a variability modelling concept that maps hardware and software components to their respective inter-dependencies, considering the system’s variability in space (i.e. system variants) and time (i.e. system versions). We also present a plug-and-play mechanism to integrate software and intelligent hardware components into the vehicle after production without expensive reconfiguration. To this end, we enhance the concept with intelligent sensor software that can extend the functionality of existing hardware sensors to minimize the need for hardware extensions. An effective and automated test method to verify many software versions and variants completes our integrated development approach.

Marc Schindewolf, Maximilian Kuebler, Tobias Pett, Lennard Hettich, Halimeh Agh, Julian Lorenz, Stefan Wagner, Michael Weyrich, Ina Schaefer, Tobias Düser, Eric Sax

The Anatomy of Software-Defined Vehicles Realized for Series with Systems Engineering

Abstract

Software Defined Vehicles promise faster time-to-market for new features, lower total cost of ownership, more secure software through faster and simpler over-the-air updates and a more desirable development environment, lowering entry barriers to automotive software development. It bears the promise of reducing the number of hardware control units, thus allowing for new, more efficient E/E architecture topologies.

This large spread in scope of potential use cases results in many different and often ambiguous expectations of what a Software Defined Vehicle actually is. We present a classification of Software Defined Vehicles applying different approaches within our safe and secure Engineering, comprising software and E/E architecture, depending on the use cases’ focus on time-to-market, packaging and total cost of ownership—or all of these.

In addition, we show how this classification represents added value in series production and we demonstrate its realization with systems engineering in a practical example.

Dominik Sieben, Dirk Macke, Jan-Philipp Hake, Stefan Kriebel, Kevin Heinen, Karthig Uthayakumar, Jörg Christian Kirchhof

Carbon Footprint Evaluation of Code Generation through LLM as a Service

Zusammenfassung

Due to increased computing use, data centers consume and emit a lot of energy and carbon. These contributions are expected to rise as big data analytics, digitization, and large AI models grow and become major components of daily working routines. To reduce the environmental impact of software development, green (sustainable) coding and claims that AI models can improve energy efficiency have grown in popularity. Furthermore, in the automotive industry, where software increasingly governs vehicle performance, safety, and user experience, the principles of green coding and AI-driven efficiency could significantly contribute to reducing the sector’s environmental footprint. We present an overview of green coding and metrics to measure AI model sustainability awareness. This study introduces LLM as a service and uses a generative commercial AI language model, GitHub Copilot, to auto-generate code. Using sustainability metrics to quantify these AI models’ sustainability awareness, we define the code’s embodied and operational carbon.

Tina Vartziotis, Maximilian Schmidt, George Dasoulas, Ippolyti Dellatolas, Stefano Attademo, Viet Dung Le, Anke Wiechmann, Tim Hoffmann, Michael Keckeisen, Sotirios Kotsopoulos

Sustainable Fuels

Frontmatter

Sustainable Fuels for Outdoor Power-Tools and Equipment

Abstract

STIHL products, particularly hand-held power and gardening tools are used around the world for shaping and caring the environment and preserving biodiversity. In the power equipment sector, as elsewhere, the transformation from petrol to battery-powered products is already in full swing. As professional users will continue to rely on high power and energy consumption in the future, STIHL is pursuing a strategy of dual technology leadership. Whilst in urban areas electric drives might prevail, in rather remote areas, combustion engines will be part of the solution. It has been proven that both technologies can be operated sustainably—either with green electrons or green molecules. While green electrons can be generated rather easily, the situation for green molecules and hence E-Fuels or Biofuels is far more complex. Various technologies for the manufacture and production of the sustainable fuel solutions are therefore the subject of intensive research and development. In addition to availability, the greatest challenge is certainly meeting the requirements that must be fulfilled to ensure compatibility of the fuels with the outdoor power equipment.

This paper shows the path STIHL has taken in the development of sustainable fuels for small engines for forestry and gardening applications and the steps that are to be taken in the future. In addition, it shows why a one-size-fits all solution, depending on the field of application, does not currently make sense.

Jens Melder, Kai Willi Beck, Armin Kölmel, Stefan Schweiger, Christoph Hiller von Gaertringen, Holger Lochmann

A Computational Study of Methanol Combustion Engine Assisted by Glow Plug

Abstract

This work explores the methanol compression ignition combustion assisted with a glow plug. The effects of the glow plug position, spray umbrella angle, the relative angle between the glow plug and jet trajectory, and the injection strategy on the engine performance were evaluated. Of these parameters, the relative angle between the glow plug and jet was found to be the dominant factor affecting the ignition and combustion heat release. At each position of the glow plug, the optimum relative angle differed due to the complex flow and air-fuel mixing within the combustion chamber. Among the four representative regions, the east region yielded slightly higher thermal efficiency and lower combustion loss. Compared to the single injection strategy, the split injection strategy was more effective in promoting the ignition process. The engine performance exhibited a high sensitivity to the pilot and main injection timings. Furthermore, the slightly narrower spray umbrella angle yielded better fuel economy because less fuel was trapped within the squish region, leading to faster flame propagation and less unburned fuel.

Xinlei Liu, Jaeheon Sim, Vallinayagam Raman, Yoann Viollet, Abdullah S. Ramadan, Emre Cenker, Hong G. Im

Thermomanagement & Supercharging

Frontmatter

Optimization of Secondary Coolant Circuit in a Small Battery Electric Vehicle Heat Pump System

Abstract

Heat pump systems combined with secondary coolant circuits offer significant advantages when used in battery electric vehicles. The systems can be designed as very compact which allows integration even into the smallest vehicles. The small refrigerant volume and possible separation of the refrigerant circuit from the passenger compartment gives the opportunity to investigate wider range of refrigerant fluids better suited to the heat pump operation. The resulting improved system efficiency directly contributes to higher BEV driving ranges; however, the additional thermal inertia of the coolant circuit potentially diminishes the advantage. To limit the negative impact, the additional components need to be considered during the system design phase. This study presents a workflow where numerical tools are used to optimize the system design in order to minimize the impact of increased system inertia due to the secondary coolant circuit. For the optimization, short city drive-cycles are considered to represent the typical use case of a small electric vehicle. Different representations of the heat pump model have been tested to evaluate the impact on the dynamic model behavior.

Marek Lehocky, Nils Framke, Jörg Aurich, Rico Baumgart

Vehicle Dynamics

Frontmatter

Metrics of Longitudinal Dynamics for Battery-Electric Vehicles

Abstract

In vehicle development, manufacturers usually strive for a distinctive and recognizable character of their products. This requires objective metrics that can describe the subjective human perception. Concerning the longitudinal dynamics of vehicles, a large number of characteristic values exist in literature. These relate primarily to the objective description of the behavior of vehicles with internal combustion engines, which were then transferred to battery-electric vehicles (BEV).

However, compared to vehicles powered by internal combustion engines, BEV exhibit different torque-speed characteristics in their traction motors. They also require distinct focal points, such as efficiency and battery temperature control. To effectively characterize the longitudinal dynamics of BEVs, specific metrics have to be defined. The metrics allow a comparison of vehicles (benchmark) and empower manufacturers to infuse their vehicles with distinctive character.

This publication will demonstrate the derivation and validation of these characteristics for longitudinal dynamics of BEV divided in five topics: acceleration and deceleration, range and charging, robustness, traction and pedal. The focus is on human perception and interaction with the vehicle, while the auditive perception stays out of scope.

Ralph Biller, Erik Ketzmerick, Stefan Mayr, Günther Prokop

Online Processing of Crosswind and Slope for Optimizing the Energy Consumption of Future Vehicles

Zusammenfassung

Light electric vehicles with less battery capacity or commercial vehicles in particular require an exact prediction of range. Differences in altitude and airstream are important parameters for the energy consumption of vehicles. The aim of the team of authors consisting of university researchers and vehicle engineers is to contribute to the careful use of energy in the mobility of the future.

Air friction is an essential component of driving resistance. Today, weather forecasting service providers offer wind data of geographical locations on a route for mobile devices. In this article, available mobile applications for wind forecasting are first analyzed with regard to their accuracy. Based on the aerodynamic principles of wind influence on vehicles, simulation calculations of the drag coefficient under different angles of attack are then carried out. Energy demand calculations according to the NEDC for an electric vehicle are then based on this. For accompanying test drives, a procedure for processing altitude data to determine the current angle of inclination is described. Documented test drives with an electric vehicle and the comparison of simulations of longitudinal dynamics with measurement results round off the article.

Andreas Daberkow, Robin Fichter, Julian Taugerbeck

Investigation of the Influence of Rolling Resistance Model Approaches on Simulated Consumption/Range

Zusammenfassung

The proportionate contribution of rolling resistance to consumption and range has increased due to the high energy efficiency of battery electric vehicles (BEV). However, rolling resistance is often considered in a rudimentary manner to simulate the vehicle drive demand at the electric drivetrain. This study examines the influence of different levels of detail in a rolling resistance model on consumption and range simulations of BEV. Therefore, based on measurement data from a whole vehicle flat-belt dynamometer, several rolling resistance models were created. These range from a fixed rolling resistance according to ISO 28580 to transient rolling resistance models. The presented method demonstrates an approach to build a robust rolling resistance model by using statistical experiment design and a sensitivity analysis. The influence of a rolling resistance model’s level of detail on simulated consumption and range is evaluated by simulating different cycles under various tire conditions with the whole vehicle simulation of the Volkswagen AG.

Enno Heese, Tim Wagner, Mohamed Ayeb, Ludwig Brabetz

Framework for ALKS Calibration using Simulation and Test Bench Measurements

Abstract

This paper presents a cost-efficient approach for optimizing parameters of an Automated Lane Keeping System (ALKS) based on simulation and test bench measurements. Metamodels are trained and used to minimize the number of actual required measurements. The approach handles multiple criteria and the combination of objective and subjective evaluations. Different Pareto-optimal parameter sets are revealed to the calibration engineer. An exemplary calibration process using the optimization tool is illustrated. Quality and efficiency of the approach are demonstrated by objective simulation data from IPG CarMaker and subjective evaluation in the Stuttgart Driving Simulator. This research enables a higher degree of automation in the ALKS calibration process and supports the automotive industry’s efforts in front-loading during development. The presented method can easily be adapted to other ADAS functions.

Kevin Knecht, Andreas Dieing, Jens Neubeck, Andreas Wagner

Detection of Driving Dynamics Anomalies Using Deep Learning

Zusammenfassung

The push towards automated and autonomous driving is enabled in part by the recent advances in machine learning. Various algorithms are entrusted with perception, planning and control of vehicles to perform the desired driving task. However, monitoring the state of the vehicle, i.e. the driving dynamics, is mandatory in such a scenario. To improve accuracy and reduce computation effort, a deep learning approach is chosen to model the driving dynamics of a vehicle using the Stuttgart Handling Roadway test bench. Different rear wheel steering controls are used to realize subtle differences in the vehicle dynamics. The resulting data is used to train different neural networks that are capable of predicting the driving dynamics of each configuration. It is shown, that the neural networks are able to differentiate between the different rear wheel steering controls.

Laurin Ludmann, Daniel Zeitvogel, Werner Krantz, Jens Neubeck, Andreas Wagner

Virtual Methods for the Consistent Development of Combined Vehicle Dynamics

Zusammenfassung

The increasing complexity and diversity of modern vehicles requires efficient development methods and processes to ensure the profitability of a vehicle manufacturer in the competitive environment. Therefore, this paper presents a generic approach and related methods for the consistent virtual development of combined longitudinal and lateral vehicle dynamics. This process is based on the established V-model from systems engineering and is exemplary applied for the development of a mid-size electric SUV. First step of the approach is the definition of vehicle dynamics targets based on objective evaluation criteria. Afterwards, these targets are translated into target ranges of the relevant systems, subsystems and components parameters of the vehicle using a simulation-based target cascading approach. To support the calibration of vehicle dynamics control systems, a virtual calibration method involving sensitivity analysis and optimization techniques is proposed. The application of the methods for the development of a sample vehicle demonstrates their effectiveness and the potential for enhancing the efficiency of the vehicle development process.

Justus Raabe, Fabian Fontana, Jens Neubeck, Andreas Wagner

Vehicle Technology

Frontmatter

Brake Emission Engineering Approaches and Outlook on Upcoming Development Tasks

Abstract

Introduction

The GTR-24 (Global Technical Regulation) by PMP (Particle Measurement Program) under the United Nations Economic Commission for Europe (UNECE) is published, even the First Amendment of it has been released.

EU 7 timeline is announced, the Brake Emission limits for Light Duty Vehicles are set, official publication is expected for mid of 2024.

Challenges & Approaches

There will be several approaches to get vehicles homologated in the future

System optimization to reach low values regarding the “individual Friction Brake Share Coefficient)
New technologies like Electromechanical Brake or Lamella Brakes
New materials (disc and pad)
Filter systems

The influence of recuperation on Brake Emissions is taken into account via so called Friction Brake Share Coefficients—depending on the degree of electrification. The foreseen possibility to create a vehicle specific iFBSC (individual Friction Brake Share Coefficient) gives some freedom to the OEMs utilizing strategy optimization.

Affected components will not only be software and functions, but also new brake system hardware like Electro Mechanical Brakes, with “true zero drag” and better controllability for brake blending—or integrated lamella brakes with no external emissions.

Another topic mainly again increasing testing efforts is the procedure for aftermarket parts.

Brake development will reach a new summit to get clean AND customer-friendly systems in the end, using more and more Simulation (e.g. Emission Modelling AI based)

Next steps on legislation side

After the official announcement of the EU 7 the respective periods will start counting down.

In order to increase the confidentiality into the procedures and laboratories another Interlaboratory study has bee initiated by the Taskforce 3 within the PMP (Particle Measurement Program). It is containing a Pre Test to select the GTR-24 compatible labs willing to be part of the main “Round Robin”, which will most likely take place in Autumn 2024

In parallel the legislator will most likely start planning for RDE and ISC, maybe also for OBD

Truck brakes are the next to be regulated.

Tires

Outlook

Another level of engineering will be caused by Brake Emission RDE Measurements, which are already announced within the GTR-24.

Truck regulations will be still more complex than passenger car ones as trucks have got a much wider range of applications. Actual topics are respective Cycles, Residual Torque and a possible calculation approach based on the Emission Legislation tool VECTO.

Implementation of ISC (In Service Conformity) is just a matter of time.

The first investigations on tire side have been kicked off—starting with abrasion.

Christof Danner

Relative Summarized Voxelization: A Novel Approach to Predict Collision Probabilities in Suspensions

Abstract

The traditional approach for collision prediction in suspension systems uses nominal kinematics and part shapes. After simulating various combinations of wheel travels and steering rack strokes, general offsets are added to the part envelopes. Afterwards the clearance between parts is rated based on experience.

The main idea of the new approach is to split the problem into two tasks: the variation in motion due to kinematic effecting tolerances and the variation in outer contours. To handle the effort, the multibody simulation is substituted by neural networks to predict the trajectory based on hardpoint tolerances. The second task can be solved by the approach of summarized voxelization, which is used to describe parts in voxel representation including the probability, that the part is in that position.

To predict the collision probability, the potentially involved voxels in a certain wheel position are relatively moved to the other part for an arbitrary number of variations calculated by the meta model. Afterwards, the moved elements can be revoxelized in the relative grid. This leads to a voxel representation which includes variation in motion and in shape. A collision calculation can be done afterwards and yields the overall probability of part collisions. In the first place, the methodology offers the opportunity to take tolerance computationally into account and also provides statistical collision information. This revolutionizes the existing clearance evaluation methods.

Alexander Großberger, Maximilian Reisner, Günther Prokop

Advanced Composite Technologies for Next Generation BEV—EMC, Crash, Thermal Management

Abstract

The While metallic structures in BEV are state of the art for the white body and the battery system, composite and plastic structures are an emerging technology. To fully exploit their potential, they need to be seen as a design-element, rather than just the replacement of a given metallic design. As composite prototypes can be more cost intense due to required mold and fixture investments, the importance of virtual design and development is even more pronounced. Hence, early sampling is avoided entirely, while serious concept decisions have to be taken. As composite battery enclosures are introduced for the first time into the market, they also include new solutions e.g. for EMC protection, crash safety, and cooling. Consequently, Experiment & CAE need to streamline every piece of data and go hand in hand. Data require to be stored with reference to each other and handled as a whole. Data mining and access to relevant meta information are key, especially when ML & genAI is utilized. Kautex designed and developed several Demo Vehicles to prove the in-situ performance of their products. Results and comparisons of composite vs. metal (both simulation & experiment) regarding EMC, Crash and Thermal Management are presented. Furthermore, the viability of the generated Data for Machine Learning techniques and genAI is demonstrated.

Bernhardt Lüddecke, Vincent Schmitz, Aryan Roknabadi, Kazim Bayramkulov, Anna Sokolova, Rainer W. Jorach, Alin Petcu, Catalin Eftenie, Mauricio Colin, David Perez

Cyberphysical Attribute Testing in Vehicle Dynamics, ADAS, and Automated Driving

Abstract

Today’s development cycles must be cost-effective, fast, flexible, and resilient. Thereby product complexity and requirements on safety, sustainability, and performance are ever increasing. The V-model is thus supplemented by agile methods, which impacts how test and simulation methods have to be combined efficiently. Cyberphysical methods are designed to support this change in system engineering methods:

1. Cyberphysical prototyping: the vehicle is divided into subsystems, each of which can be developed using respective testrigs and/or simulation models. Testrigs and simulation models can be coupled in real time to form cyberphysical full vehicle prototypes. Digital twins of testrigs and highly advanced control concepts are required.

2. Human centered attribute development: cyberphysical prototypes can be experienced subjectively at every development stage, if coupled with a highly immersive driving simulator. Moreover, driver experience and driver behavior can be understood and predicted by feeding measured driver behavior into driver models.

3. Smart test environments for automation and connectivity: the cyberphysical prototype has to be considered in context to its environment (road space, informational radio connections). The appropriate test environment is to combine physical vehicles with simulators for several traffic participants.

Prototypes for these instruments are being developed at TU Dresden. Their role in modern development is demonstrated in the presentation

Günther Prokop, Clemens Deubel, Rico Zimmermann

Erratum zu: Degradation Model of Hairpin Winding in Inverter-fed Motors Considering Thermal and Electrical Stress

Chuxuan He, Philipp Mell, Michael Beltle, Martin Dazer, Stefan Tenbohlen

Backmatter

Title: 2024 Stuttgart International Symposium on Automotive and Engine Technology
Editors: André Casal Kulzer
Hans-Christian Reuss
Andreas Wagner
Publisher: Springer Fachmedien Wiesbaden
Electronic ISBN: 978-3-658-45010-6
Print ISBN: 978-3-658-45009-0
DOI: https://doi.org/10.1007/978-3-658-45010-6