Skip to main content

Virtual Component and System Integration for Efficient Electrified Vehicle Development

Periodic Reporting for period 1 - VISION-xEV (Virtual Component and System Integration for Efficient Electrified Vehicle Development)

Reporting period: 2019-01-01 to 2020-06-30

The VISION-xEV project aims at developing and demonstrating a generic virtual component and system integration framework for the efficient development of all kinds of future electrified powertrain systems.

The need to meet future fleet CO2 emission limits will lead to a further increased introduction of a broad range of electrified vehicle configurations to the portfolio of the European OEMs. A significant effort regarding methods and tools is therefore required to enable the development of the diverse future electrified powertrain systems at minimum additional cost.

An electrified powertrain is a highly complex mechatronic system and meeting all functional and performance requirements efficiently demands a highly integrated development approach. Micro- and mild-hybrid architectures add moderate complexity to the conventional powertrain. However, the further step towards heavy electrification, aimed at a largely improved overall energy efficiency and unconditional emission legislation compliance under RDE conditions, requires advanced design and optimization methods and tools to master the related development challenges. It is the goal of VISION-xEV to contribute to this by joining the expertise of all partners involved.
In a first step, the research activities were mainly focused on performing a thorough analysis of electrified/hybridized vehicle architectures, components and sub-systems technologies, the related development processes and tasks as well as the currently adopted modelling, simulation and testing techniques. This analysis resulted in the identification of white spots and gaps regarding currently available models and simulation methods and led to the derivation of the requirements for components modelling and system integration. This also resulted in the specification of four industrial use-cases. In addition, an experimental campaign with three plug-in hybrid vehicles was carried out to generate model validation data and reference drive cycles as the basis for virtual-/simulation-based development and assessment of electrified/hybrid vehicles.

Regarding advanced integrated modelling of energy storage components, electrical and thermal characterization of battery and super-capacitor cells have been performed. Multi-dimensional and system-level battery cell, module and pack models were set up adopting the experimental cell characterization data and electro-thermal models. Multi-physical e-machine simulation was focusing on integrated and reduced modeling of the electric and magnetic domains as well as thermal domains with integrated fluid flow. Multi- dimensional and system level multi-physics models of an inverter were built considering the relevant electrical, thermal and fluid-flow processes for both detailed and fast and transient calculation of the power losses in the inverter. Model order reduction approaches were elaborated to derive system level e-component models directly from detailed high-fidelity simulation results.

With regards to classic thermodynamic powertrain components, fluid-flow and thermal integration, engine models have been set up and validated using experimental data. Detailed CFD simulations have been carried out to predict the complex three-dimensional flow field in a turbocharger turbine under continuous and pulsating flow conditions. Experiments for different turbocharger configurations were used to develop an innovative power-based approach to approximate the amount of heat transfer in the turbocharger. For assessment of the thermal management of internal combustion engines models of both coolant and air circuits were set up. Engine tests have been carried out for enabling comparison of simulation results with measured data. Detailed multi-dimensional modelling has been adopted for heat loss prediction in exhaust aftertreatment systems under zero flow conditions and new models for simulation of electrically heated catalysts and components adopting phase change materials were set up.

Detailed information on the individual component models and related input/output data have been exchanged for clarification of the model interfacing options for system integration. Furthermore, component and sub-system models were exchanged and first prototyping activities regarding model interfacing and coupling were successfully started.
The VISION-xEV research and development activities of the first period resulted in scalable models, methods and experimental data for supporting future modeling and simulation of electrified/hybrid powertrain components and sub-systems, e.g.
o advanced battery, super-capacitor, inverter and e-machine models,
o extended models of internal combustion engines, charging and aftertreatment systems,
o models of engine thermal management validated based on measurements,
o experimental data for model validation and reference drive cycles
as well as specification of suitably extended and adapted interfacing and co-simulation requirements to enable seamless coupling of the individual components and sub-systems, regardless of the underlying modelling platform.

A major focus of the research and innovation activities in the second period of VISION-xEV is on the implementation and validation of robust and efficient model coupling strategies. These are aimed at facilitating a seamless interfacing/co-simulation of the dedicated system-level component and sub-system models of the partners. Demonstration and validation of the newly developed models and methods as well as of the model coupling strategies is based upon four selected industrial use-cases.

A battery development use-case is dedicated to the relevant aspects regarding packaging of the battery with special emphasize on thermal integration, i.e. on proper cooling under all relevant driving and ambient conditions. The xEV-powertrain configuration use-case is aimed at the assessment of strategies and methods for virtual minimization of the overall vehicle energy consumption under real driving scenarios. It comprises the analysis and assessment of the influence of the e.g. technology and sizing of the adopted e-components, transmission configuration, powertrain components cooling and passenger compartment HVAC system configuration, etc. The engine and aftertreatment system definition use-case is related to the integration of phase change material elements within three-way catalyst modelling to support identification of the potential of such technology and to adapt proposed configurations to obtain faster validation than based on full experimental evaluation of several prototypes. The mid-size urban bus HEV use-case is aimed at supporting the optimum choice of xEV powertrain components and sub-systems. For this purpose, the component and system integration framework developed in the project is used in the concept phase for laying out the possible component combinations and matching them against mission requirements. Potential variables considered are the powertrain architecture (e.g. serial hybrid, parallel hybrid, power split), choice of available sub-system technology, performance of subsystems, power, size and combustion type of ICE as well as performance of electric components, demonstrated for a mid-size urban bus HEV configuration.