Automated Schematic Design of Power-Split Hybrid Vehicles With a Single Planetary Gear

Abstract

Most of the previous research in the field of power-split hybrid electric vehicles focused on the powertrain topology optimization. However, depicting a given or found topology in the form of schematic diagram, required for the advanced steps of vehicles’ design, has not yet been studied. In this paper, we propose a systematic approach to automatically generate all feasible stick diagrams for all twelve split-hybrid powertrain topologies with a single planetary gear (PG). The stick diagram is a simplified cartoon layout that schematically illustrates the connections, arrangements, and positions of the powertrain components. The proposed process is divided into three steps. First, we introduce the placement diagram, which specifies the position of the components with respect to the planetary gear. Secondly, for each placement diagrams, all positioning diagrams are generated where the relative location of each component is determined. The use of positioning diagrams guarantees dealing with all the possible arrangements. Lastly, the feasible stick diagrams are selected by filtering out infeasible ones from the entire pool of candidate stick diagrams using a set of feasibility rules. The proposed method is used for several topologies, such as Toyota Prius and GM Volt, and it is found that the patented stick diagrams are a subset of all the feasible stick diagrams. Therefore, one can systematically generate all the feasible stick diagrams for any given single PG powertrain topology using the proposed design methodology.