Examination of particulate contamination contents in commercial diesel fuel

Authors

• Zbigniew Stępień Oil and Gas Institute – National Research Institute, Lubicz 25A, 31-503 Kraków, Poland
• Magdalena Żółty Oil and Gas Institute – National Research Institute, Lubicz 25A, 31-503 Kraków, Poland

DOI: https://doi.org/10.30678/fjt.91711

Keywords:

abrasive particles, hard particles, diesel fuel

Abstract

The purity of diesel fuel is a crucial issue, in particular in the face of modern injection systems operating under very high pressures with very precisely fitted mating parts. At such pressures and in high temperatures, injectors are particularly exposed to abrasive wear due to the presence of fine, hard abrasive particles in diesel fuel.

This article presents the results of diesel fuel contamination with abrasive particles in various size ranges (above 1, 2, 3, 4, 6 and 14 µm) determined in accordance with ASTM D7619 and EN 12662. Fuel samples came from leading manufacturers and were collected at filling stations which are the last links of the distribution chain. Furthermore, all diesel fuels were tested for compliance with all the requirements of EN 590.

Analysing the results obtained, the problem of contamination with abrasive particles was found to be present in Poland. Around 37% of the samples tested did not meet the requirements of the Worldwide Fuel Charter (WWFC) in terms of purity class (ISO code 18/16/13 for particles in the range above 4, 6 and 14 µm according to ISO 4406). Violations of the purity class were found mainly for particles in the range over 4 µm. A very large number of particles from the lowest ranges, which are not included in the Worldwide Fuel Charter (above 1, 2 and 3 µm), were also found, and these may cause damage to fuel injection systems. The number of particles in the range above 1 μm in majority of samples exceeded the class 22, and that of those in the range above 2 and 3 μm was mainly between classes 19 and 21. Moreover, no correlation was found between the results of the particulate matter determination (ASTM D 7619) and the total impurity content (EN 12662).

Based on the results of the tests carried out, it can be concluded that exceeded number of particles in individual size ranges are not always related to the content of impurities in a form of metallic pulp, impurities from outside the system or the precipitation of enriching additives. Nevertheless, they may be one of the factors contributing to damage to precision fuel injection systems.