Paving The Way For Heavy Duty Synthetics

Synthetics deliver on performance and lower emissions

Synthetics Synthetics

With fuel prices rising, delivery deadlines getting tighter, and truck drivers in short supply, fleet operators continue to look for ways to streamline their operations and reduce operating and maintenance costs. It means more than focusing only on the initial purchase price of the truck, but instead on reducing the total cost of vehicle ownership. Fleet operators want improved durability in their trucks to limit turnover and to lower capital expenditures over the long term. They need greater reliability to help increase overall fleet productivity. And they need greater efficiency from their vehicles to decrease their operating costs and fuel spend.

 

Hardware designs have evolved significantly over the last 30 years to keep up with demands of increasingly stringent regulations. With each change, new demands have been placed on the lubricating oil. With tighter tolerances between components, today’s advanced engine technologies achieve greater efficiency, but are more sensitive and run much hotter than previous designs. And when the engine runs hotter, so too does the oil, which has prompted new demands on oil quality.

 

Like most things, too much heat can stress the oil. It makes it more vulnerable to breakdown, which can cause it to degrade. Severely oxidized oil will become much thicker than when the oil was new, and can also become acidic and attack internal components like bearings and bushings. Oxidized oil also contributes to deposit formation in places like the turbocharger and power cylinder. Elevated temperatures can also cause a portion of the oil to evaporate, which can impact oil consumption and further accelerate degradation.

 

Of course, engines and the oils that protect them must be robust not only at elevated temperatures but also at the very low temperatures encountered upon winter startup. Fluids that can handle these wide temperature swings have what oil formulators call high “viscosity index.”  Increasingly, we turn to synthetic oils that, when formulated with high performance additives, deliver on the high stability, low volatility, and high viscosity index that today’s operators demand.

 

It's helpful to understand the difference between conventional and synthetic oils. Conventional oils are made from refined crude oil and undergo further processing to remove harmful impurities and to further tailor their properties. In contrast, synthetic base oils are purposely built chemicals that are synthesized to deliver high performance. Synthetic base oils are generally less volatile, and more chemically stable than conventional base oils. Yet, they are particularly robust at low temperatures as well.

 

Of course, it is not just the synthetic base oil that delivers these properties, but also the additive package that is unique to each producer. The greatest potential for high performance comes from the optimal combination of synthetic oils and additive formulation expertise. The properties we often attribute to synthetics are actually the result of the additives working with the base oil to produce the desired performance. More simply stated, not all synthetics are created equal.

 

With the trend toward smaller, technologically advanced heavy-duty engines, we have seen a parallel trend toward lower viscosity lubricants. This is leading logically to the wider use of synthetic blends, and ultimately, full synthetic engine oils. With the right additive formulations, synthetic lubricants will help deliver on the goals of lower emissions and high fuel economy that truck manufacturers have been working towards. Fleet managers would do well to understand the benefits of synthetics and to prepare for this transition as they upgrade their fleets.

08/18/2021

Shawn Whitacre
Shawn’s career spans 25 years focused exclusively on research and engineering dealing with heavy-duty engine lubricants, fuels, emissions, and materials. Before joining Chevron in 2013, he spent 12 years leading global fluids and materials engineering activities for Cummins. He also spent five years conducting lubricant, fuel, and emission research for the Department of Energy’s National Renewable Energy Laboratory in Golden, CO. At Chevron, he is a Senior Staff Engineer primarily responsible for product formulation of the Delo Brand of Heavy Duty Engine Oils. Whitacre is the chairman of the ASTM Heavy-Duty Engine Oil Classification Panel, which was tasked with the final development of the API CK-4 and FA-4 specifications that took effect in late 2016.

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