Impact of the technical condition of main pumps on fuel consumption in a hydraulic excavator

During the operation of hydraulic excavators, the technical condition of pumps deteriorates due to wear, leading to increased internal clearances, fluid leakage, a reduction in volumetric efficiency, and higher energy losses, ultimately resulting in excessive fuel consumption. The objective of this study was to determine the optimal service life of pumps, taking into account the growing fuel overconsumption during operation. The following tasks were addressed: developing a mathematical model for pump ownership costs, incorporating progressive fuel overconsumption; designing an algorithm and conducting computer simulations using Simulink-Matlab; and assessing the increase in fuel consumption. The study examines the impact of the technical condition of the main hydraulic pumps on fuel overconsumption using the Komatsu PC2000-8 hydraulic excavator as a case study. Based on the proposed pump operation cost model, which accounts for the increase in fuel consumption over time, dependencies between fuel overconsumption and pump wear were established. Computer modeling was performed in Simulink-Matlab and Excel based on the developed calculation methodology and software algorithm. Relationships between the excavator’s fuel overconsumption and the technical condition of the pumps were identified. A mathematical model for pump ownership costs is presented, taking into account the progressive fuel overconsumption during operation, along with the resulting equation for determining the optimal service life of pumps to minimize total costs, including pump acquisition and fuel expenses. This expression considers the technical condition of the main pumps, their rate of deterioration, fuel costs, and pump replacement costs. A fuel overconsumption indicator was introduced, defined as the ratio of the difference between actual fuel consumption per 1 m3 of excavated material and fuel consumption at nominal efficiency of the main pumps (nominal fuel consumption) to the nominal fuel consumption. The application of this criterion, in conjunction with the proposed equation for determining the optimal pump service life, allows for a data-driven selection of the critical wear threshold for the main pumps, reducing total ownership and fuel costs by up to 17%, depending on economic and mining-engineering conditions.