Automotive diesel oil

Diesel oil is the fuel for motor propulsion which is mainly benefiting from the technological development of Diesel-cycle compression-ignition internal combustion engines.
It is, in fact, in this engine field where the most important innovations are registered in terms of both performance and consumption. It is therefore not a coincidence that these engines are on increasing demand for cars even of small/medium cylinder capacity.

Cetane number, properties when cold as well as cloud point or CFPP (Cold Filter Plugging Point), plus lubricity are the most important characteristics from the point of view of the use of the product.
The cetane number indicates the self-ignition capacity of diesel oil. The higher this number, the easier for the diesel oil to self-ignite in the diesel engine, where the combustion of the air-fuel mixture occurs spontaneously (compression-ignition engine) thanks to the high temperature reached in the cylinder at the end of the compression stage.

Today the minimum cetane number required in normal diesel oils for automotive is 51.
Other important characteristics for the automotive diesel oil are the properties when cold, for example the cloud point – which represents, in Celsius degrees, the temperature at which the fuel starts to become opaque – and the CFPP (Cold Filter Plugging Point) that is the temperature at which the product no longer flows within a specific time inside a specific filter.

For such reason the automotive diesel oil has its “seasonality” and during the winter period there are special diesel oils available: for example Arctic diesel is fully efficient up to a temperature close to 21º below zero.

The third relevant characteristic for the use of automotive diesel is the lubricity, or the lubricating power of the diesel oil itself. Following the continuous reduction of the sulphur content in the automotive diesel oil for environmental reasons, the increasingly intensive desulphurisation processes also resulted in the elimination of the components that naturally confer the oil a lubricating power (lubricity).