A Study on Integrated Optimality and Optimal Structure Changeover of Hybrid Systems. An Investigation into Life-Cycle Optimality and Leading Design of Vehicles.

Abstract

This paper investigates the integrated optimality and optimal structure changeover of hybridtype systems. The environmental issue on the earth forces engineering design to configure new machines or equipments to reduce energy consumption or carbon dioxide gas release. While there are a few successful design implementations, it is essential to establish rational design scenario or methodology to accelerate a new design paradigm. This paper demonstrates the importance of system-based design and system-level optimality, which are accessed with any mathematical means, with an example of leading design of vehicles toward life-cycle optimality. After providing general conception, the system structure of vehicles are compared among gasoline internal combustion engine vehicle, THS-type hybrid electric vehicle and genuine electric vehicle in the aspects of fuel economy, total cost and life-cycle-based environmental impact. Furthermore, the influences of battery performance progress and the external changes such as environment taxation system or fuel price on the system structure optimality are outlined as examples of the utility of system-based optimal design methodology.