Ash in Gas Engine Oils
WHAT IS SULPHATED ASH? Sulphated Ash (Sulfated Ash) is the percentage of oil that remains after burning it, treating the initial residue with sulphuric acids,…
Category: Engine Oils
How Does Motorsport Technology Transfer Into Consumer Engine Oils?
Rafe sits down with Tomek Young – Global Motorsports Manager at ExxonMobil to discuss all things regarding the relationship between oil companies and motorport teams.…
How Does the Development Cycle of a Racing Oil Occur?
Rafe sits down with Tomek Young – Global Motorsports Manager at ExxonMobil to discuss all things regarding the relationship between oil companies an…
Why do Oil Companies Participate in Motorsports?
Rafe sits down with Tomek Young – Global Motorsports Manager at ExxonMobil to discuss all things regarding the relationship between oil companies and motorport teams.…
What is Nitration of Lubricating Oil?
Nitration refers to an unfavourable condition in which the oil in gas engines is saturated with insoluble or soluble nitrogen oxide compounds. The combustion chamber…
How do Antiwear Additives Work?
Anti-wear additives are an essential component of most lubricants including engine oils, hydraulic oils, turbine oils, or gear oils. They help us protect components by…
The hydrodynamic lubrication regime encompasses the right side of the chart, but at low ZN/P values we're specifically talking about the boundary and mixed lubrication regimes. In order to have a low value on the x-axis, either N needs to be small (slow speed) or P (load) could be very high and because it's in the denominator it will make the term smaller.
We're therefore talking about slow speed, high load operations or a combination of both. Under these conditions the load is shared between both the fluid and the surface. Under boundary lubrication there is full metal to metal contact and all of that load is really being taken by the metal surface. With no protection for the machine surface the situation would lead to extreme wear of components.
To alleviate the situation we must turn to additives, of which there are two large groups - solid and reactive additives.
The most common antiwear additive is ZDDP as it can be manufactured at relatively low cost that has really good at anti-wear benefits. ZDDP is a combination of thiophosphoric acid, as well as zinc oxide. Sometimes we call ZDDP a metal salt because it's the product of a reaction of between an acid and a base. Acid plus base makes salt plus water.
These sacrificial films therefore form a hard barrier above the component surface, protecting it from abrasive / adhesive wear in highly loaded application.