In order to meet various regulations, refineries are required to produce low sulphur and Ultra low sulphur diesel. Sulphur is reduced by a process known as hydrosulphurisation. However, in the process of reducing sulphur, certain naturally occurring polar compounds, which lend lubricity to the fuel, are also removed. Lubricity enhancing compounds are naturally present in diesel fuel derived from petroleum crude by distillation. Diesel lubricity is largely provided by trace levels of naturally occurring polar compounds which form a protective layer on the metal surface. They can be altered or changed by hydrotreating, the process used to reduce sulfur and aromatic contents. However, lowering sulfur or aromatics, does not necessarily lower fuel lubricity. Typical sulfur compounds are not responsible for the lubricity characteristic of diesel; rather it is the nitrogen and oxygen containing hetero-compounds that majorly contribute to this characteristic. Because hydrosulphrisation is not a selective process it removes S as well as N & O. The removal of N and O from hetero-compounds destroys their ability to perform as lubricity agents. Thus, low S fuels have lower levels of active N and O compounds and thus worse lubricity. Lubricity is a fuel quality that prevents or minimizes wear in diesel fuel injection equipment. A fuel lacking lubricity can cause severe wear and premature failure of the fuel pump and injection systems. In essence, the lubricity improver additive diesel makes up for the loss of naturally occurring compounds, which provide lubricity to the fuel. The lubricity additive works by the principle of boundary lubrication. Here, it forms a molecularly thin layer which gets adsorbed on the metallic surfaces resulting in drastically reducing wear.

CRISTOL Lubricity Improver for Diesel (LI) Series are non-metallic, phosphorus free additive that maintains lubricity in low sulphur diesel. The lubricity improver forms a thin protective film on the surface of the metallic injection systems that acts as a boundary when two metal surfaces come in contact.


  • Product does not interact with any other constituents in the fuel or the fuel itself
  • is completely compatible with the same.
  • Product does not interact with engine lubricants.
  • Product protects against corrosion.