Impact of fuel on real diesel injector performance in field test

Abstract

This work assessed the potential impact of diesel fuel complying with the EN 590 standard on real diesel injector performance in a long-term field test. Injector deposit formation has been attributed to diesel fuel instability during storage in relation to fuel injection equipment (FIE) operating conditions. These deposits can occur at different locations within FIE and impact on fuel spray characteristics, causing threats to the proper functioning of the fuel injectors. The long-term field tests were performed with two new vehicles fitted with an advanced common rail (CR) fuel injection system, meeting the requirements of Euro 5. A high quality diesel fuel meeting the requirements of the EN 590 standard was used for both vehicles. A scanning electron microscope with energy dispersive X-ray spectrometry (EDS) and an electron backscatter diffraction (EBSD) detector was used for observation and imaging of external, coking injector deposits around the nozzle fuel-flow holes and internal diesel injector deposits (IDID) in the area of the nozzle needle. An elemental analysis was performed by energy dispersive X-ray spectroscopy analysis (EDX). Evaluation of the macroscopic characteristics revealed that, despite the formation of external and internal injector deposits, there was no measurable loss of flow through the injectors. As a result, while injector deposits have adverse impacts on some injector macroscopic characteristics, they did not cause a significant deterioration of the injectors’ operating characteristic and their real performance.