Why today’s engine lubricants are more complex than ever

Increased fuel efficiency and reduced emissions are never far from peoples’ conversations within the industry. The continuing drive to a cleaner and more environmentally-friendly future has forced significant changes in engine hardware and aftertreatment systems.

In order for new passenger cars to achieve the ever tightening emissions standards (currently Euro 6), the engine lubricant is having to perform in hotter and more severe operating conditions.

The widespread use of diesel particulate filters (DPFs) is being followed by gasoline particulate filters (GPFs) in petrol vehicles; removing small but harmful particulate matter from the vehicle’s exhaust gases. Engine lubricants with lower levels of sulphated ash, phosphorous and sulphur (SAPS) are formulated to ensure after treatment devices perform efficiently throughout their lifetime.

In addition to original equipment manufacturer (OEM) oil specifications, lower SAPS lubricants are generally aligned with the ACEA ‘C’ categories of service-fill oils. In contrast, the use of higher SAPS lubricants (ACEA ‘A’ and ‘B’ categories) could lead to reduced power, lower efficiency and ultimately blockage of the particulate filter, along with an expensive yet avoidable repair bill for the vehicle owner.

The drive to increased fuel efficiency has led to the development of lower viscosity engine lubricants. While today’s well accepted SAE 5W-30 viscosity grade delivers fuel economy gains against older 10W-40 grades, the advancement of engine hardware and lubricants means this will be superseded by more efficient and higher performance SAE 0W-20 and 0W-16 grades. The move to lower viscosity grade engine lubricants as a means to increase fuel efficiency is only going to continue.

However, increased efficiency doesn’t lie just with lower viscosity grade lubricants. OEMs are moving to reduced “high temperature high shear” (HTHS) viscosity engine lubricants for their latest engine hardware designs in order to deliver greater efficiency and fuel economy.

In an operating engine, the lubricant is required to lubricate and protect areas under high shear conditions at high operating temperatures. HTHS dynamic viscosity is the current industry standard test that best predicts fluid behaviour in the operating conditions of an engine.

In lower HTHS viscosity lubricants, the resistance to flow of the oil is less, meaning the engine needs to generate less power to maintain performance and so less fuel is consumed. Moving to lower HTHS viscosity engine lubricants, for example from 3.5 mPa.s to 2.9 mPa.s, delivers fuel efficiency bene ts at the same viscosity grade.

As engine lubricants can have the same viscosity grade but different HTHS viscosity, awareness and understanding of both is important. It is essential that the correct OEM recommended engine lubricant is used to ensure it provides the necessary engine protection as well as offering the opportunity for fuel efficiency benefits.

Carlube Triple R engine oils offer a future- proofed, differentiated and technically superior solution. The requirement for higher performance, lower viscosity, fuel efficient lubricants is increasing. Carlube Triple R offers a wide range of vehicle specific oils with manufacturer approvals.

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