BIZOL OIL EXPLAINER: CLASSIFICATION

Oils and terminology

Question, where do the different oils actually come from?

The graphic shows the production chain up to the point where the base oil is produced. The first step is extracting it from the ground. The next step is transporting the extracted crude oil to the refinery where it is split into fractions. The fractions are distilled as shown in the graphic and the lubricant manufacturer purchases the respective base oil from the refinery and turns it into the final product.

Figure 1 – Fractional distillation of oil

What does oil contain?

As we have discussed previously, engine oil is made up from a cocktail of base oil and additives. The graphic shows the typical make-up of a modern engine oil.

Figure 2 – Typical oil composition

It may come as a surprise to some that engine oil contains such a high percentage of additives. But without the additive package, the oil simply could not do what is required of it. The actual number of additives and the amount of additive used in a formulation varies. Most commercially available oils have a base oil content of around 60-90%, depending on the additive package needed to fulfil specifications.

Differences in the amount of wear inhibitors, corrosion inhibitors, antioxidants, viscosity index improvers etc affect how well the engine is protected from wear and the amount of deposit formation. The quality and suitability of an oil depends on the lubricant producer getting the science and the mix of additives absolutely right.

Before blinding you with science, we thought it might be a good idea to explain some of the jargon, so here’s a brief overview of some of the terminology used when talking about oil.

Table 1 – Overview of typical oil terminology