IC engines have been the dominant automotive powertrain in the 20th century because of their advantages in power density, thermal efficiency, simplicity, durability and mobility. Condensing 100 years of information on automotive engine system technology evolution shows five different development stages: “bone and muscle”, “instinct”, “nerve and brain”, “intelligence”, and “system optimization”. Currently, the last step is facing the pressure of the “clean revolution” plus the “e-commerce revolution”. To meet future emission requirements and reduce CO2 emissions, the conventional engine system will be pushed to new physical limits, leading to higher cost and reduced durability. Therefore, the automobile industry should consider re-engineering or system optimization of the engines, including configuring the system architecture to be as transparent as possible to suit the fast changing environment of e-commerce.
A hybrid powertrain is an ideal solution to meeting future fuel economy and emission regulations because it reduces much of the burden on the engine. From a system standpoint, the most important feature of a hybrid powertrain is the primary power unit, either IC engine or fuel cell, can be partially decoupled from the vehicle driving dynamic demands, yielding benefits such as zero-emission driving mode, no idling, no cold start emissions, no transient fuel compensation, easy control, simple engine calibration, etc. Furthermore, since heat engines and fuel cells cannot restore energy, a secondary energy system should be considered to recover braking energy. Finally, if the transient energy demand, including the initial launching, is taken care of by the electrical subsystem where no mass transfer problems exist, the overall system behaves more like a linear system and its control can be transparent and open.
Implementation of all the new hybridization features that increase the likelihood of the system achieving the lowest emissions and highest fuel economy will lead many engine technologies to become obsolete. Correspondingly, the capital investment and engineering focus will be shifted, and the new system's open architecture will provide many opportunities for engine suppliers to improve the technology and cut costs quickly. This transparent system structure and its fast R&D response will change the engine product nature to more e-commerce styling.