Experimental study on energy flow loss mechanisms of hydraulic excavators under real-world operating characteristics

Abstract

Abstract

The energy efficiency of hydraulic excavators is significantly influenced by operator behavior, yet the quantitative relationship between operating characteristics and system-level energy flow loss mechanisms remains poorly understood. Current evaluation methods often rely on multi-cycle averaging, which obscures the dynamic impact of human factors under varying operating conditions: idling, moving, and working states. This study proposes a data-driven framework based on real-time field measurements to identify operator-dependent energy inefficiencies and clarify energy flow loss mechanisms in hydraulic excavators. We parameterize operator control behaviors (driving styles: small, medium, and large opening) and predefined control strategies (driving modes: fine, general, and heavy-load) to systematically quantify their effects on energy flow loss and efficiency across different swing amplitudes within the working condition. Results indicate that throttling losses and deceleration overflow losses are the dominant sources of energy waste, which are ultimately dissipated as thermal energy and affect the thermal stability of the hydraulic system, with efficiency variations strongly dependent on swing amplitude. For 90° swings, the medium-opening driving style achieves a favorable trade-off between time and energy use, reducing consumption by 15.6% compared to the large-opening style while maintaining comparable cycle time. For 180° swings, the same style improves efficiency by 29.3% and reduces energy use by 17.7% relative to the small-opening style. Differences among driving modes become more pronounced with increasing swing amplitude. During 360° working cycles, the heavy-load driving mode increases system efficiency by 28.3% but raises total energy consumption by 105.2%. In contrast, the general driving mode offers a more balanced improvement, boosting efficiency by 23.6% with a moderate 56.1% increase in energy consumption. These findings underscore the critical influence of operator driving styles and system-defined driving modes on energy flow loss and thermal performance, and reveal key loss mechanisms contributing to energy waste in construction machinery. This work provides actionable insights for improving equipment design, refining operator training, and developing intelligent control systems, supporting cleaner and more sustainable construction operations.