Powertrain sizing of electrically supercharged internal combustion engine vehicles

We assess the concept of electrically supercharged internal combustion engines, where the supercharger, consisting of a compressor and an electric motor, draws electric power from a buffer (a battery or a supercapacitor). In particular, we investigate the scenario of downsizing the engine, while delivering high power demands by supercharging. Simultaneously, we seek the optimum buffer size that provides sufficient electric power and energy to run the supercharger, such that the vehicle is able to deliver the performance required by a driving cycle representing the typical daily usage of the vehicle. We provide convex modeling steps that formulate the problem as a second order cone program that not only delivers the optimal engine and buffer size, but also provides the optimal control and state trajectories for a given gear selection strategy. Finally, we provide a case study of sizing the engine and the electric buffer for different compressor power ratings.