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About this book

This work presents an investigation of the influence of different modeling approaches on the quality of fuel economy simulations of hybrid electric powertrains. The main focus is on the challenge to accurately include transient effects and reduce the computation time of complex models. Methods for the composition of entire powertrain models are analyzed as well as the modeling of the individual components internal combustion engine and battery. The results shall help with the selection of suitable models for specific simulation tasks and provide a deeper understanding of the dynamic processes within simulations of hybrid electric vehicles.

About the Author

Florian Winke was research associate at the Research Institute of Automotive Engineering and Vehicle Engines Stuttgart (FKFS), where he worked on modeling and simulation of hybrid electric powertrains. After finishing his doctorate, he joined a German automotive manufacturer, where he is working in software development in the field of hybrid operation strategies.

Table of Contents


Chapter 1. Introduction

Since the beginning of industrialization, the demand for individual mobility has been continuously increasing. Fast growing populations and people striving to improve their standards of living lead to rapid increases in vehicle numbers and traffic. Figure 1.1 illustrates that the trend towards more vehicles continues until today, even in industrialized regions.
Florian Winke

Chapter 2. Powertrain

For this work, multiple powertrain models were developed that differ in the way that dynamic effects are taken into account. All of these models were built up with a modular structure so that it is possible to interchange and compare different sub models of the powertrain components.
Florian Winke

Chapter 3. Internal Combustion Engine

Within a parallel HEV powertrain, the internal combustion engine represents the determining component with respect to fuel consumption and pollutant emissions. Several different approaches can be taken for the simulation of internal combustion engines. The following list presents the most common model types in order of increasing complexity.
Florian Winke

Chapter 4. Battery

As the secondary energy storage, batteries are key components in hybrid powertrains. Even for charge sustaining hybrids, where ultimately all energy comes from fuel, the efficiency and the dynamic behavior of the electric energy storage has a significant impact on the fuel consumption and driving performance. However, the availability of detailed models is often problematic which is why it is important to understand the impact of battery models with different complexity on powertrain simulations.
Florian Winke

Chapter 5. Summary and Conclusion

For this work, a range of component and powertrain models for HEV were developed. The main goal was to provide an overview of possible modeling approaches and their impact on the results of consumption and CO2 oriented simulations. In order to understand the underlying mechanisms and to analyze varying boundary conditions, a set of engine and vehicle concepts was developed that stretches from a Sub-Compact Car to a fullsize SUV and from a naturally aspirated 2-cylinder MPI engine to a turbo charged 4-cylinder DI engine (all SI engines).
Florian Winke


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