Abstract
Research and/or Engineering Questions/Objective
A concept optimization method for a platform underpinning both conventional and electric vehicles is described.
The viable solution is reached by analyzing all together design variables & constraints, solving conflicting objectives among all underpinned vehicles, achieving the best balance between ergonomics roominess, vehicle performance, development investment and manufacturing cost among all vehicles.
Methodology:
A Multi-Objectives Optimization Model (MOOM) has been built and implemented to define the optimal solution for the shared platform among electric and conventional vehicles. The conflicting objectives of this platform sharing have been taken as optimization variables,
i.e.:
- Space: EV module packaging space vs. ergonomics roominess;
- Weight: Maximum payload of suspension vs. light weight design target of conventional vehicles;
- Cost: Special components/tooling vs. manufacturing cost/ investment.
Besides, some optimizations constraints are also considered in the model, such not to penalize in roominess the conventional car because of the sharing with the electric car.
An ideal goal threshold is set for each variable, and all the variables are weighted according to the importance to the global variable in this model. The model calculated all the solutions which should fulfil the thresholds of all variation.
In the end a Pareto-optimality is defined by considered the weighting of each variable.
Results:
The analysis has given an optimal solution for the design of electric & conventional vehicle platform that can underpin A0 to A class (Europe class B-C) conventional vehicle and a A0-class (Europe class-B) electric vehicle;
As first application, two vehicles, a A0-class BEV crossover and a A-class conventional sedan have been finished their concept design and relevant CAE validation, these two vehicles share most of the rolling chassis, E/E, and interior components; The cost of the electric vehicles is sustainable due to the high sharing rate with conventional vehicles.
Limitation of this study:
This strategy of platform sharing among electric and conventional vehicles allowing to bring upward at sustainable cost the performance of the electric ones has reached up to now about 40-50% of validation, achieved by means of both the above mentioned two SOP cars and several prototypes of following new cars.
What does the paper offer that is new in the field including in comparison to other work by the authors?
This paper offers a novel approach to tackle with a complex case of platform definition, facing objectives and constraints all together.
It is based on MOOM, a technique mainly used in the field of design refinement, applied here to the technical and economical optimization in the concept definition phase of a platform underpinning electric and conventional cars.
Conclusions:
The multi-objectives optimization has proved to be a valuable tool in the concept definition of a vehicle platform shared among several vehicle, some of them electric and the others conventional.
It allows to analyze all key variables together: BOM cost & investment, roominess & range, technological risk. And it has reached a viable solution.
KEYWORDS – multi-objective optimization; electric vehicle; modular design; (Give five (5) keywords that describe the content of the technical paper. Use 12 point text.)