Institut für Fahrzeugtechnik
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Die Entwicklung komplexer, vernetzter mechatronischer Systeme erfordert von angehenden Ingenieur:innen nicht nur Fachwissen, sondern auch fundierte Methodenkompetenzen im Systems Engineering. Dieser Beitrag präsentiert das praxisorientierte Lehrkonzept des Projekts DriveOhm der Technischen Hochschule Nürnberg, das Studierenden SE-Methoden durch anwendungsnahe Erfahrungen vermittelt. Als experimentelle Plattform für problembasiertes Lernen dienen speziell ausgestattete Modellfahrzeuge. In Teamarbeit entwickeln Studierende damit eigenständig mechatronische Fahrzeugsysteme, wie z.B. Fahrerassistenzsysteme, und wenden dabei zentrale SE-Methoden aus den Bereichen Requirements Engineering, Systemarchitekturentwicklung sowie Verifikation & Validierung an. Die Evaluation zeigt, dass die Modellfahrzeuge ein effektives Mittel sind, um theoretisches Wissen mit praktischer Anwendung zu verknüpfen und SE-Kompetenzen nachhaltig zu fördern. Der Beitrag diskutiert Erfolgsfaktoren und Herausforderungen bei der Umsetzung dieses didaktischen Ansatzes in der ingenieurwissenschaftlichen Lehre und zeigt auf, wie der spielerische Zugang über die Modellfahrzeugen nicht nur die Motivation steigert, sondern auch zur besseren Vorbereitung auf die berufliche Praxis beiträgt.
The debate over synthetic fuels is intense especially in sectors with a high energy demand like maritime [1, 2]. Hydrogen production from renewable sources is growing, but immediate measures for decarbonization are needed [3, 4]. In this context, the project MethMag was funded, and a gas engine for methane combustion with an innovative cooling concept and a purged prechamber (PC) spark plug was virtually developed [5, 6]. Validation with data from the test bench demonstrates that the simulations accurately represent the operating conditions [7, 8].
This combustion process is adapted for ammonia, which is being considered as a climate-friendly fuel of the future, particularly in maritime transportation [4, 9]. This fuel faces significant combustion challenges and is therefore mostly considered in complex, bivalent systems [10]. In particular, the prechamber is examined regarding the ignitability of ammonia. The overarching objective is to eliminate the necessity for a secondary fuel system, thereby reducing system complexity and associated costs.
The transition to ammonia highlights the need for further adjustments. The geometry of the PC cap significantly affects turbulence and mixture formation in the prechamber [11]. While swirl caps generate high turbulence, the mixture formation is inadequate. Tumble caps, on the other hand, provide advantages in mixture formation by achieving an earlier increase in turbulence, even though the maximum turbulence is lower. For ammonia combustion, PC wall conditioning is not essential, given the inherently low combustion temperatures. However, conditioning can improve cold-start behavior by accelerating PC combustion and offering greater flexibility in ignition timing [12]. Direct injection into the prechamber enhances fuel mixing and reduces sensitivity to ignition timing adjustments. This leads to higher efficiency and better combustion characteristics, particularly at lean air-fuel ratios [13, 14]. Operating with a lean ammonia-air mixture is challenging but offers benefits for non-selective catalytic reduction (non-SCR) of nitrogen oxides. Simulations show that operation with λ = 1.2 and λ = 1.4 is feasible, although efficiency decreases at leaner mixtures [15].
Systems Engineering in der ingenieurwissenschaftlichen Lehre: Herausforderungen und Good Practices
(2025)
Interdisziplinäre Zusammenarbeit und ganzheitliches Denken sind essenziell, um drängende gesellschaftliche Herausforderungen wie den Klimawandel durch technische Innovationen zu bewältigen. Systems Engineering hat sich in der Industrie als bewährte Methodik zur Entwicklung komplexer mechatronischer Systeme etabliert und bietet auch für die ingenieurwissenschaftliche Lehre großes Potenzial. Am Beispiel des studentischen Projekts DriveOhm der TH Nürnberg wird gezeigt, wie Systems Engineering erfolgreich in die Lehre integriert werden kann. Studierende entwickeln mithilfe eines speziell ausgestatteten Modellfahrzeugs eigenständig Fahrerassistenzsysteme und wenden Methoden wie Requirements Engineering, Systemarchitekturentwicklung und Verifikation & Validierung an. Der vorliegende Beitrag präsentiert die erstmalige Umsetzung des Lehrkonzeptes, identifiziert Good Practices und diskutiert Herausforderungen dieses Ansatzes.
Harmful NOx emissions generated during rapid changes in engine’s speed and load (such as acceleration or deceleration) are strongly linked to deviations in air-to-fuel ratio (λ) from its optimal setpoint. These deviations arise under transient conditions due to several factors, including sensor resolution limitations, time delays between actuators and sensors, and inaccurate air mass estimation within the engine management system.
While fuel mass control has significantly improved over the past three decades - achieving superior performance in terms of both dynamics and accuracy through the use of multiple injections per engine cycle - the primary challenge remains the precise control of air mass, particularly under transient conditions. Nonlinear wave dynamics and the inertia of the engine’s air path make traditional solutions, such as slow and inefficient actuators like the butterfly valve, inadequate.
This paper introduces a novel methodology to address these limitations by developing a device that is an order of magnitude faster than a butterfly valve while minimizing flow losses. The design philosophy is outlined, and the flow bench setup used to evaluate the performance of an instrumented prototype is presented. High-frequency data collected during testing are analyzed, and the extracted flow structure and turbulence parameters are discussed.
Finally, the dynamic performance of the newly developed device is incorporated into a transient gas exchange engine model, where its capability to control λ on a cycle-resolved basis is evaluated against a conventional throttle body. Numerous studies have proven that NOx spikes during engine’s accelerations and decelerations are well correlated to λ deviations from its setpoint. The assessment of the emissions reduction strategy under transient conditions is based on the device's precision in managing λ during each engine cycle, as derived from the transient model output.
Over the last decade, the prevailing demand for renewable energy sources initiated the electrification of the transportation sector, with the development of H2 engines and fuel cell powertrains increasingly gaining momentum alongside battery electric vehicles. One of the essential tasks to optimize the overall efficiency of these drives is to precisely, dynamically and frictionless meter the reacting gases into the conversion chambers. In this paper, we propose a novel dosing system, focusing on gases (air), that is based on the principle of a variable Venturi nozzle, which incorporates a device for rapid variation of the effective flow cross-sectional area (EA) with negligible pressure losses. Each EA corresponds to a demanded load or mass flow and thus enables a dynamic control of the stoichiometry (l) of the machine. Our patented technology mainly consists of two surfaces perpendicular to the flow direction where one is fixed in space and the other one is moving at high frequency (> 20 Hz) towards or against the flow direction. Firstly, the underlying design philosophy and the details of the first prototype are presented, followed by an extensive description of the test bench setup, including data acquisition system. This is succeeded by a thorough analysis of the high-frequency data to extract flow characteristics and turbulence parameters. Subsequently, the transient performance of the Venturi system is experimentally compared with that of a throttle body. Finally, the capability of the Venturi system to precisely control the cycle-resolved air-fuel ratio of a hydrogen engine is demonstrated through transient simulation results based on a class B car operating under the FTP-75 driving cycle.
Herausforderungen und Lösungsansätze für die Umfelderkennung von automatisierten Rangierlokomotiven
(2024)
Autokorso vs. Norisring
(2024)
This fundamental work explains in detail systems for active safety and driver assistance, considering both their structure and their function. These include the well-known standard systems such as Anti-lock braking system (ABS), Electronic Stability Control (ESC) or Adaptive Cruise Control (ACC). But it includes also new systems for protecting collisions protection, for changing the lane, or for convenient parking.
The book aims at giving a complete picture focusing on the entire system. First, it describes the components which are necessary for assistance systems, such as sensors, actuators, mechatronic subsystems, and control elements. Then, it explains key features for the user-friendly design of human-machine interfaces between driver and assistance system. Finally, important characteristic features of driver assistance systems for particular vehicles are presented: Systems for commercial vehicles and motorcycles.