Energy efficiency of series hybrid power system for transit buses estimation of charge-discharge loss of generated electric energy on board

The driving conditions of suburban transit buses were investigated with a chartered bus, Based on this data, a series hybrid system was designed for transit buses from the viewpoint of the acceleration performance and the energy saving, In order to measure the electric energy flow on board, the dynamometer bench tests and the static simulated experiments were carried out with storage batteries and ultra capacitors. It was clarified that the charge discharge loss in the storage devices can be estimated by the calculation using the internal resistance and current. And, the energy efficiency of the series hybrid system was evaluated in compared with conventional engine powered buses for a trial.