How does digital engineering drive electrification? Hybrid vehicles have been developed as a form of alternative mobility to comply with increasing international regulations for a sustainable future. In this scenario of major changes in policies and accelerated technological evolution, a digital model is essential to maintain competitive development times, identify project bottlenecks in the early stages and reduce or eliminate the cost of building unnecessary prototypes.
Model Building
Consider the initial scenario of an electrification project: I have my vehicle's specifications, a variety of components to evaluate, and several possible configurations for the arrangement of these components. How to analyze the impact of these choices on final performance? Traditionally, responsible engineers use heuristics to reduce the universe of decisions to a handful of possibilities, which can then be evaluated by the team in the early weeks of the project. Alternatively, it is possible to set up a digital representation of the system in Simcenter Amesim , as in the simulation below.
Configuration of a parallel hybrid vehicle
Configuration of a series hybrid vehicle
Configuring components from business data allows you to quickly evaluate key system metrics in different scenarios. To compare performance between the two architectures, we chose three driving cycles representative of real conditions:
Urban Dynamometer Driving Schedule (UDDS): American standardized test that represents urban driving conditions
Highway Fuel Economy Test cycle (HWFET): highway driving cycle with a high-speed profile used to determine the fuel economy rates of light vehicles
My daily route to work: the cycle is automatically generated by Amesim using public GPS and traffic data.
In general, the engine of a parallel configuration can be smaller than that used in a series architecture, as it transfers work directly to the wheels without losing energy for electromechanical conversion. For this study, the same engine was used in both configurations, and the other components were chosen to be as similar as possible.
Analysis
After a few seconds of simulation we obtain a concise summary of the performance of the configurations in each cycle.
In a quick analysis we can see that the series architecture is a little more efficient in urban driving conditions. Furthermore, the driving cycle results obtained by GPS are consistent with those obtained by UDDS.
Another critical parameter is battery power consumption and savings during the driving cycle. This is called SOC ( State of Charge ). The batteries are recharged during braking or when the SOC reaches certain limits, determined by the chosen control strategy.
What does all this mean?
As seen above, Simcenter Amesim represents the electric vehicle system by a comprehensible and highly customizable diagram, which allows rapid determination of vehicle subsystems from commercial data for rapid validation of new components and configurations in pre-design stages. In more advanced stages, it is possible to detail the control strategies and performance curves of critical components, such as batteries and motors, for a simulation of critical factors — for example, heating and energy demand. All of this makes it possible to evaluate the functioning of the project in conditions close to real ones from the initial stages.
The only way to balance a large number of variables is to consider them comprehensively from the beginning of the process. In the digital world, the evaluation of different scenarios is optimized to save team work time, reduce time to market for the final product and enable evidence-based design decisions, resulting in greater added value to the final product.
In addition to system modeling, when geometric aspects and spatial distribution of the quantities involved are relevant, digital engineering employs multiphysics virtual prototyping in 3 dimensions, considering fluid dynamic, thermal, chemical, structural, acoustic, electromagnetic effects, complex materials, constructive forms and manufacturing processes.
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