It’s an open secret that a modern diesel engine is only as efficient as the lubricant inside, which is why engine oil has become equally important to those in commercial road transport as the hardware around it.
According to Aleks Urosevic, Senior Technologist at Castrol, modern-day diesel engine oil is not only meant to keep moving metal surfaces separated – especially at high-pressure contact points in the engine valve train – but also to extend vehicle life in general and reduce fuel consumption along the way.
One key constituent of that mammoth task is deposit reduction, he says, as the accrual of excessive residue around a piston cannot only result in ring sticking and abrasion, but also in cylinder wear, which will shorten engine life and increase oil consumption. According to Aleks, that’s why many a synthetic oil now includes ‘active molecules’ that are able to prevent build-up before it can cause any trouble.
While trying to manage deposit and wear control, experienced oil companies are also working to counteract exhaust-gas acid, which can lead to corrosion inside the engine. To avoid such a scenario, they add special substances to the oil that are able to neutralise it as it flows past areas that are especially exposed to chemical damage.
Given the potential value added to a trucking organisation – not just in reduced maintenance cost, but in overall asset utilisation – much of the debate is currently centred around switching from standard oil to more complex synthetic alternatives like Castrol’s top-shelf Vecton product, says Aleks.
According to the oil specialist, the lower viscosity oil is able to reach critical components in less time than a standard product whilst providing extra protection at temperatures where a conventional alternative might fail. In doing so, Aleks says a traditional 5W-30 could potentially deliver “useful fuel savings” compared to a typical 15W-40 while also extending the recommended oil drain interval – of course depending on engine type, service type and operating environment.
“Especially with trucks built to the most recent US or European emission standards, you need to make sure you use the right oil to keep them happy,” he says. “The more complex a truck becomes, and the more stringent your target is in terms of fuel burn, the more you need to look at the oil you use to get those extra few per cent out of the engine without taking a risk.”
Going forward, the showdown may become even more interesting, as a new US heavy-duty diesel oil standard is currently underway that could see even more oils surface that are specifically designed to reduce the level of greenhouse gas (GHG) emissions and deliver fuel economy improvements along the way – with some of them becoming so advanced that they won’t be backward compatible anymore. “There’s a new heavy-duty diesel oil standard in the works in North America. It will not be available until mid to late 2017, but the performance requirements for it tell you a lot about where the diesel engine industry is headed,” says US journalist Tom Jackson of Equipment World.
According to Tom, the new standard is necessary because the US are pushing ahead with a new fuel efficiency standard in 2017, paving the way for lower viscosity oils with additional performance features like the one Aleks was testing in Melbourne. “While none of the lube oil formulators are ready to publish numbers yet as to what the new FA-4 lubricants will deliver in terms of fuel efficiency, studies have shown that using conventional low-viscosity oils will result in about a one per cent gain in fuel efficiency [when compared to a 15W-40 lubricant],” he says – adding that to understand which oil will ork for which application, there will have to be a whole new nomenclature as well.
“The current heavy-duty diesel engine oil standard is known as CJ-4, as designated by the American Petroleum Institute (API, ed.). The new standard is being called by its working name: PC-11, or Proposed Category 11,” he explains. “Once licensing begins, the oils will probably be designated by the API nomenclature of CK-4 along with a low-viscosity formulation likely to be named FA-4. This would be the first time the API designates a split standard [and] the difference is largely a matter of the different needs of on-road and off-road diesel engines.”
Building on the complexity of current-day oils, the low-viscosity FA-4 formulations will be formulated with lower high-temperature, high shear (HT/HS) properties in order to improve the fuel economy of next generation, low-emission truck engines, says Aleks. “However, they might not be backward compatible with engines older than 2016-2017.”
To make sure that those who need the high HT/HS capabilities of a CK-4 oil can still be serviced, CK-4 oils will remain backward compatible with all trucks and off-road equipment that use the current CJ-4 standard. According to Tom, that distinction will become especially important for those who need help protecting their engines in high-heat, high-load applications such as off-road or mining.
To help end users better distinguish between API CK-4 and API FA-4 oils, the API is considering an additional designation on the viscosity grades, adds Tom. Oils with low HT/HS may be designated with an ‘L’ at the end of the viscosity nomenclature, while those with higher HT/HS capabilities may be marked with an ‘H’ at the end of the designation.
In preparing for future legislation change, Aleks says the Castrol team, for example, is now regularly involved in fleet management consulting. “You would find many a fleet out there that has been working with Castrol for 25 years or so, because they know we have the expertise to supply the right oil for both current and next generation engines Australia-wide,” he says.
“As a result, we not only have to work with government and the manufacturing industry to ensure we have the right oil available to help next generation engines run smoothly, but also with those who use the equipment in the field.