Wednesday 22 September 2021

Oiling the way to environmental gains

Nigel Bottom, managing director of Witham Group, explains how the latest lubricants are helping to reduce CO2 emissions and improve fuel economy

While the drive towards a greener and more sustainable commercial transport fleet has been a journey that the developed world has been on for decades, we are fast reaching a point where mechanical intervention and enhanced design of the internal combustion engine has taken us as far as possible – hence the introduction of hybrid and electric vehicles.

So, with the drive to lower and lower emissions showing no sign of slowing down and the climate rightly at the top of almost everyone’s agenda, what else can be done?

Lubricants have always played a fundamental part in the reduction of emissions, with lubricant manufacturers developing suitable fluids in partnership with OEMs for each new generation of engine; however, they look set to play a much larger future part in the drive for sustainability.

Additive chemistry has now required a complete redesign with the introduction of low SAPS – sulphated ash, phosphorus and sulphur – oils. These components can poison exhaust after-treatment devices used to achieve Euro emissions standards for pollutants and stop them working, so need to be reduced in the finished lubricant.

Viscosities are reducing; ten years ago the standard viscosity grades for heavy duty engines were 20W-40 or 15W-40. Today the vast majority of OEMs are recommending 5W-30 and even 5W-20.

Why is this? The simple answer is friction – the lower the viscosity of the fluid, the less energy (fuel) is required to circulate it. The less fuel used, the less carbon emissions produced.

This has however required the shift from traditional mineral oils to more sophisticated synthetic formulations which has inevitably increased the cost of compliant engine lubricants.

Numerous studies are available detailing fuel savings of between 1-1.5 per cent where moving from a 15W-40 to a 5W-30. Given fuel is often in the top three running costs for hauliers this can, however, more than offset the increased cost of the lubricant.

We as a company have made the transition to lower viscosity engine and transmission fluids across our own small fleet of mixed aged trucks, and achieved an overall 1.38mpg fuel saving, hopefully demonstrating real world benefits.

The use of biodiesel is also a positive step in reducing the overall carbon footprint, and their use is ever increasing – but in 2019 they made up only 5.1 per cent of all road and non-road fuel, so there is still work to do here.

Fuel economy and the use of biodiesel look set to form an ever-increasing part of emissions reduction. So much so that ACEA (the European Automobile Manufacturers Association) who set the lubricant specifications for Europe and include as members all the major OEMs have included specific tests in their upcoming 2021 specification sequences for heavy duty diesel fuel economy (F11 & F8).

There is also already a CEC-SG-L-109 biodiesel oxidation bench test that determines the effect that fuels with biodiesel content can have on the finished lubricant in the current ACEA 2016 specifications.

It has never been more important to use the correct fluid with the appropriate specification and chemistry. We simply need to look at how far vehicles have evolved over the past 10 years to realise that the fluids that maintain and protect them have had to evolve alongside.

Witham Group’s website offers a tool to help fleets identify the correct lubricant for the correct application:

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