Böhme, Maximilian; Gerdts, Matthias; Trapp, Christian. (2023). Backend-Based State-of-Charge Control as a Predictive Operating Strategy for a Serial PHEV. Stuttgart International Symposium (23., 2023, Stuttgart), S. 1-16.


In previous work, a serial hybrid powertrain concept with a phlegmatised ICE has been described. Drivability is to be ensured through an innovative predictive operating strategy. Battery State-of-Charge (SoC) is controlled using a backend-based prediction of energy consumption on a given route based on road map and traffic data.

In this paper, a spotlight is thrown on the proposed control architecture. On the top level of the controller, a Dynamic Programming algorithm finds an optimal reference trajectory for the SoC over a known route with the goal of avoiding certain Worst-Case scenarios commonly associated with the serial hybrid powertrain topology. Close adherence to the reference trajectory is ensured on a lower level through Model Predictive Control, taking into account additional factors such as battery stress. These control layers closely represent the map DATA distributed on the on-board bus network of state-of-the-art road vehicles under the current ADASIS standard. The necessary input data for the proposed controller is therefore available at no extra cost or engineering effort to OEMs. A simulation framework based on Matlab/Simulink and AVL CruiseM enables testing of the operating strategy using high-quality, open-source map DATA. Thus, the viability of the proposed control architecture is demonstrated in a selection of challenging driving scenarios on real-road speed and gradient profiles. It is shown that this quite basic prediction algorithm outperforms classical, non-predictive serial hybrid operating strategies in terms of drivability. Thus, systematic optimisation of the ICE towards high efficiency and low emissions is enabled, reducing requirements for transient behavior and high power density. Potential for future development, especially further improvements of efficiency and emissions behavior of the ICE through predictive thermal management, is also elucidated.



Kottakalam, Saraschandran; Alkezbari, Ahmad Anas; Rottenkolber, Gregor; Trapp, Christian. (2023). Developing optical measurement techniques for improving ignition simulation models. International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (14., 2023, Barcelona).


Computational Fluid Dynamics (CFD) simulations are an important part of the development of new combustion strategies and innovative powertrain concepts. Since the ignition model initiates combustion in CFD simulation models of spark-ignited engines, it is crucial to have an ignition model that accurately represents the phenomena. Therefore, it is essential to have a fundamental physical understanding of ignition phenomena in order to optimise spark-ignited engines to meet customer expectations and regulatory requirements. This study presents new experimental/ measurement techniques developed with a focus on validating and improving existing ignition simulation models. These newly developed tests are used to observe sparks in an optically accessible flowbench capable of reproducing engine operating conditions. Through these tests, spark parameters such as spark elongation and phenomena such as the interaction of the spark with the surrounding medium have been observed and quantified. The knowledge gained was used to calibrate and improve an existing ignition simulation model.




Grundl, Larissa; Sundaram, Pravin K.; Pang, Genny A.; Trapp, Christian T.; Loffredo, Francesca. (2023). Alternative combustion concept for a highly phlegmatized hybrid powertrain: Simulation and validation of dual fuel homogeneous charge compression ignition engine using chemical kinetics with 1D simulation and 3D CFD software. International Vienna Motor Symposium (44., 2023, Wien).


Trapp, Christian; Sotiropoulou, Emmanuella; Tozzi, Luigi. (2022). Phlegmatized ethanol ICE using innovative prechamber spark plug technology for serial hybrid applications. Internationales Stuttgarter Symposium Automobil- und Motorentechnik (22., 2014, Stuttgart).


This paper proposes a serial hybrid concept for an automotive powertrain running on re-newable ethanol. All transient power requirements are covered by a smart battery system with high power output at a moderate capacity, enabling the internal combustion engine to operate quasi stationary, requiring only 3-5 operating points to cover the average power. This allows for a significant increase in vehicle efficiency, even when considering the addi-tional energy conversion losses within a serial hybrid. AVL Cruise is used to determine the required operating points for WLTC and real-world driving, as well as the vehicle efficiency and emissions. A combination of 1D analysis and 3D CFD, in addition with engine testing, is used to develop the combustion solution. The innovative DI ethanol engine with turbulent flame jet ignition, via prechamber spark plug, has a compression ratio of 13:1 and is running at lambda 1.9 with a BMEP of 16 -18 bar and a speed of 1200 – 3000 rpm. The engine effi-ciency is between 42% and 44% and due to the low raw emissions, an oxidation catalyst and a SCR-System with moderate conversion rates are sufficient to meet the proposed Euro 7 limits.

Trapp, Christian & Böhme, Maximilian. (2022). Innovative, modular serial hybrid concept for a highly efficient, clean automotive powertrain. Internationales Stuttgarter Symposium Automobil- und Motorentechnik (22., 2022, Stuttgart).


Global transport and mobility are responsible for around 25 % of the greenhouse gas emis-sions and thus one of the key areas to address global warming and reach the Paris climate goals. Additionally, a further stringent reduction of vehicle related emissions is required by upcoming regulations like Euro 7. Different applications, from small, short range urban vehicles to long haul, high load trucks require different power train performance and renewable energy storage to meet the vary-ing requirements while meeting the above targets. In the future, there will be a mix of BEV, PHEV, FCEV and ICE only powertrains using energy from renewable sources like biomass and renewable power or gaseous and liquid fuels like Hydrogen, Methanol, Ethanol or e-gasoline derived from that. The Universität der Bundeswehr has developed a unique modular power train concept based on a serial hybrid architecture which can be used as basis for BEV, PHEV and FCEV.The powertrain concept is based on scalable and interchangeable building blocks: an innova-tive smart battery with cell integrated power electronics and a new multiphase electric motor including the respective power electronics are defining the BEV configuration, adding a fuel cell and hydrogen tank system extend this to a FCEV vehicle, adding an ICE and hydro-gen or ethanol / methanol tank system extend this to a PHEV. Both, the fuel cell and the ICE are profiting from the serial hybrid concept used, as all tran-sient energy requirement will be covered by the smart battery system with high power output at a moderate capacity and thus small size and weight. The fuel cell and the ICE can be operated quasi stationary, only requiring 3-5 operating points to cover the average pow-er needed or to boost when more power than available from the battery is needed. As both have only to cover the average power requirements of the vehicle, the fuel cell and the ICE can be relatively small and thus designed to be long-life and cost effective. For the ICE, this quasi-stationary operation allows also for ultra-low raw emissions and thus requires only a simplified after treatment system to meet even Euro 7.





Evaluation of Ignition Modeling with AVL FIRE

AVL User Conference

Cost Effective and Reliable Solutions for Gas Engines in Stationary and Mobile Applications Using Advanced Passive Prechamber Technologies

29th CIMAC World Congress on Combustion Engine Technology

Maximizing the Efficiency of High Speed, Power Generation Engines – Prometheus Prechamber Spark Plug Technology

11th Dessau Gas Engine Conference


GE’s J920 gas engine – 10, MW power and more than 50 % electrical efficiency

MTZ Industrial Sept. 2017

Further improvements in steady state and transient performance of GE’s Jenbacher type 6 gas engine

 Proceedings of "Der Arbeitsprozess des Verbrennungsmotors" Graz

GE’s J920 Großgasmotor kombiniert wegweisende Technologien und innovatives Digital Monitoring, um mehr als 50 % elektrischen Wirkungsgrad zu erreichen

Proceedings of the Vienna Engine Symposium

GE’s J920 gas engine – 10,4 MW power at up to 50 % electrical efficiency

Proceedings of the Dessauer Gas Engine Conference

Gasmotoren und gasförmige Kraftstoffe

Handbuch Dieselmotoren, Herausgeber Helmut Tschöke, Klaus Mollenhauer und Rudolf Maier, Springer Vieweg

How to translate the theoretical potential of applying variable valve timing on large stationary gas engines into actual benefits

 Proceedings of "Der Arbeitsprozess des Verbrennungsmotors" Graz

Moderne Großgasmotoren für die dezentrale Energieversorgung der Zukunft

"Der Verbrennungsmotor – ein Antrieb mit Zukunft"; Herausgeber: Antje Hein und Tilo Roß, Springer Vieweg



"Erdgas und erneuerbares Methan für den Fahrzeugantrieb"; Springer-Vieweg Reihe „Der Fahrzeugantrieb“, Herausgeber: Michael Bargende, Richard van Basshuysen und Helmut List


Cylinder pressure based controls for robust operations of gas engines of high power density

Dessauer Gasmotorenkonferenz

GE‘s J920 FleXtra Gas Engine – 60 Hz Application and Further Improvements for low NOx Emissions

Dessauer Gasmotorenkonferenz


Nutzung von Gichtgas im Großgasmotor mit Hilfe zylinder-druckbasierter Motorregelung und Zweigasbetrieb

3. Rostocker Gasmotorenkonferenz

Flammentomographie zur Bewertung des Verbrennungs- und Klopfverhaltens eines hocheffizienten Großgasmotors

11. Internationales Symposium für Verbrennungsdiagnostik, Baden-Baden

Großgasmotoren - Technologien für zukünftige Herausforderungen des Marktes und der Gesetzgebung

Seminar Verbrennungsmotoren, Karlsruher Institut für Technologie, WS 2013/14


LEC-GPN - A New Index for Assessing the Knock Behavior of Gaseous Fuels for Large Engines

4. Internationale Tagung ottomotorisches Klopfen, Berlin

GE’s Intelligent Controls – The Smart Path to the Next Level of Power Density and Efficiency for Large Bore Gas Engines

Der Arbeitsprozess des Verbrennungsmotors, Graz

Zukünftige Gasmotoren - Technologien für zukünftige Marktbedürfnisse und Gesetzgebungen im Vergleich zum Diesel

Der Arbeitsprozess des Verbrennungsmotors, Graz

Konzept für direkt gezündete Großgasmotoren

MTZ 5/2013

GE’s all new J920 gas engine- a smart accretion of two-stage turbocharging, ultra lean combustion concept and intelligent controls

CIMAC congress 2013, Shanghai

Large Gas Engines - 75 mg/Nm3 @ 15%02 NOx 'Engine-Internal Measures or Exhaust Aftertreatment?

CIMAC congress 2013, Shanghai

The Potential of Exhaust Gas Recirculation in Large Gas Engines

CIMAC congress 2013, Shanghai


Bewertung von Simulationsmodellen zur Brennverfahrensauslegung für die neue Generation von Großgasmotoren

10. Internationales Symposium für Verbrennungsdiagnostik, Baden-Baden

Technologiebausteine für direkt gezündete Hochleistungsgasmotoren

MTZ Heavy Duty Conference

Die neue Gasmotorengeneration von GE Jenbacher – mit zweistufiger Aufladung zu höchsten Wirkungsgraden

32. Wiener Motorensymposium


J624 – der weltweit erste Gasmotor mit zweistufiger Aufladung

MTZ 04/2011

Technologiebausteine künftiger Großgasmotoren – höchste Wirkungsgrade bei geringen Emissionen

Der Arbeitsprozess des Verbrennungsmotors, Graz

Utilization of Special Gases in Stationary Gas Engines

MTZ Industrial 01/2011

The next generation of GE’s Jenbacher Gas Engines – a groundbreaking combination of two stage turbo charging and innovative combustion concepts

7. Dessauer Gasmotorenkonferenz


Aktuelle Herausforderungen bei der Entwicklung von Brennverfahren für Großgasmotoren

1. Rostocker Großmotorentagung

Zweistufige Hochdruck-Turboaufladung für Gasmotoren mit hohem Wirkungsgrad

15. Aufladetechnische Konferenz, Dresden

The gas engine of the future – innovative combustion and high compression ratios for highest efficiency

CIMAC Congress


Sondergase aus Industrieprozessen – neue Ressourcen für Energieerzeugung mit Verbrennungsmotoren

4. Tagung Gasfahrzeuge, Stuttgart

Zündungskonzepte moderner Großgasmotoren – ein Blick in die Zukunft

Der Arbeitsprozess des Verbrennungsmotors, Graz


Simulation in der Motorentwicklung - Auf dem Weg zur virtuellen Applikation

MTZ 11/2008

SCR im Ottomotor -Potenziale und Anwendungsmöglichkeiten

Internationales CTI-Forum SCR-System, Bonn

CO2-Potenziale heutiger und zukünftiger Ottomotoren – Konsequenzen für die Abgastechnik

Internationales CTI Forum Abgastechnik, Nürtingen


Lean boost and NOx – strategies to control nitrogen oxide emissions

Direkteinspritzung im Ottomotor VI, HdT, Essen

Strategien zur Minderung der CO2- und Stickoxidemissionen bei zukünftigen Ottomotoren

MTZ 09/2007

Verbrennungsanalyse und -simulation: Schlüsselwerkzeuge im Entwicklungsprozess

Internationales CTI Forum Brennverfahren, Stuttgart

NOx emission control options for the Lean Boost downsized gasoline engine

1. IAV MiNox Conference, Berlin


Ottomotoren mit Benzindirekteinspritzung – eine einfache Modellierung der Energiefreisetzung im geschichteten Magerbetrieb

Dr.-Hut Verlag, München


Development without samples – gasoline injetors – generation next


Potential eines direkteinspritzenden Ottomotors mit Abgasturboaufladung

Stuttgarter Symposium

Abschlussbericht „Potentialabschätzung der Aufladung an einem direkteinspritzenden Ottomotor“

VDMA Gesellschaft für Forschung und Innovation (VFI) mbH, Frankfurt



Skript, Institut für Verbrennungsmotoren und Kraftfahrwesen der Universität Stuttgart