Investigation of Aging Effects on Combustion and Performance Characteristics of Mining Engines

The sustainability of mines is becoming ever more important to reduce the greenhouse gas footprint and keep the resources extraction economically sustainable. Despite the electrification and hybridization trend of mining equipment, Diesel engines are still expected to maintain their importance as a primary source of power especially for open pit equipment, thanks to their longer operating range. However, in order to keep high efficiency and minimize fuel consumption for the entire operating life it is crucial to understand and tackle the ageing effect on the engine performance. In this research a 500-h durability test was performed on a Liebherr mining engine, with the aim of better understanding how ageing affects the combustion process and engine performance (power and fuel consumption), and how this effect can be compensated. Experimental results show a 1% specific fuel consumption increase, ascribable to injector aging. Moreover, with the objective of emphasizing other possible opportunities to further reduce fuel consumption, the possibility of cancelling cylinder-to-cylinder disparities (maximum IMEP variations of 7% compared to the average value of 12 cylinders) and optimizing the calibration setting near the reliability limits (BSFC decrease by 0.7%, compared to the base calibration), were investigated in the paper. The role of cylinder pressure-based closed loop control systems as enabling technology to seize these potential benefits is discussed in the article.