Against the backdrop of the global energy crisis and the urgent pursuit of dual-carbon goals, improving energy efficiency and reducing energy consumption in construction machinery have become central to the industry’s green and low-carbon transition. As key equipment in infrastructure construction, hydraulic excavators generate considerable gravitational potential energy in the boom during cyclic operations. However, the throttling losses inherent in conventional valve-controlled systems not only waste energy but also cause system overheating and reduced efficiency. Owing to its four-quadrant operating capability and high efficiency, the four-quadrant pump-controlled system provides an effective technical platform for recovering boom potential energy. Therefore, this paper presents a comprehensive review of four-quadrant pump-controlled boom energy recovery (FQ-PCBER) systems. First, three representative system architectures—electric, hydraulic, and hybrid—are examined, and their technical characteristics, performance limitations, and applicable scenarios are compared. Subsequently, the review focuses on the control challenges associated with these systems and summarizes advanced control strategies. Finally, practical engineering issues, technical challenges, and future research directions are discussed. This review aims to provide researchers with a clear technical roadmap, accelerate the practical implementation of four-quadrant pump-controlled boom energy recovery technology, and support the green and low-carbon transformation of the construction machinery sector.
Li et al. (Thu,) studied this question.