Review of hybrid electric systems for construction machinery

A large amount of construction machinery results in an enormous waste of energy and is a serious source of air pollution. Increasing fuel efficiency or using cleaner energy has become the most fundamental methods to solve this problem. First, this paper briefly introduces hybrid electric system (HES) structures. Second, HES for several types of construction machinery are comprehensively discussed and compared. Third, energy-saving control strategies for construction machinery are analysed in detail. Finally, the prospects and challenges of HES research for construction machinery are presented.