NACFE: Fleets should switch to low-viscosity engine oils

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Fleet Owner  /  June 28, 2016

Latest Confidence Report highlights fuel economy savings and potentially longer drain intervals of low-viscosity engine oil blends.

The latest Confidence Report issued by the North American Council for Freight Efficiency (NACFE) indicates that Class 8 tractors can gain anywhere from 0.5% to 1.5% in fuel economy when switching from 15W-40 oils to current CJ-4 5W-30 or 10W-30 blends or to CK-4 5W-30 and 10W-30 blends derived from the new PC-11 classification, which will be available in December this year.

NACFE’s researchers also found a further 0.4% to 0.7% gain in fuel economy on top of that 0.5% to 1.5% improvement can be obtained by switching to the new FA-4 low viscosity PC-11 variant, though the backward compatibility of that oil remains a major unknown, according to Mike Roeth, the group’s executive director.

“Fleets don’t want two oils in their systems: we heard that loud and clear in our interviews,” he explained in a conference call with reporters. “So we hope to see work go on to approve these oils as far backward as possible.”

He added that it “feels like we’ve got a tipping point here” in terms of getting the trucking industry to switch to lower viscosity oils, even the new FA-4 grade despite that backward compatibility issue.

“The old axiom that heavier oils will protect my engine better is falling apart now,” Roeth said. “I went in with assumption that FA-4 would not backward compatible. But as we start testing older engines with the newer [FA-4] oils, it may be. I expect there to be a growing amount of test data on this.”

In engineering terms, the reports primary author Yunsu Park noted that “viscosity” is defined as a measure of a fluid’s internal resistance to flow. Thus within a truck’s engine, mechanical losses from pumping and friction consume approximately 16% of the total energy input to the vehicle. Using lower-viscosity oil, then, will reduce such engine mechanical losses – thereby reducing fuel use.

Though NACFE is recommending that fleets use the low-end of the fuel economy scale in its report – 0.5% – to conduct payback analysis regarding a switch to low-viscosity blends, Roeth noted that “a half percent fuel economy at $2 or $3 per gallon [diesel] fuel is still hundreds of dollars in savings per truck per year.”

NACFE noted several other factors that need to be weighed if fleets contemplate switching to low-viscosity engine oils:

• For fleets using non-synthetic 15W-40 oils there is a cost entailed in switching to low-viscosity engine oil, largely due to the fact that much of the 15W-40 oil found on the market today is mineral-based;

• At the retail level, a switch from mineral-based oils to synthetic blends typically increases cost by 30% to 40%, even within the same brand family. Therefore, a higher price for engine oil will increase maintenance costs over the lifetime of the switch.

• Yet NACFE’s research also found switching to lower-viscosity oil may allow a fleet to consider an extended drain interval, which can help offset that price premium.

• Although the ability to extend drain intervals varies greatly by various factors such as duty cycle, one fleet that this study team interviewed extended its drain interval by 20,000 miles by switching to lower-viscosity oil.

“In grand scheme of things, in terms of fuel savings, 0.5% not a very high number,” noted Park during the conference call. “But [the switch] is very basic and is implemented easily: no real change to maintenance practices is required and there is no added weight or extra components to the truck. Even assuming just 0.5% benefit, get a decent return on that investment. Assuming [a fleet is] getting enough miles on [its] trucks, this is one that fleets should certainly adopt.”

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Low-vis lube brings modest fuel saving for modest investment

Today’s Trucking  /  June 28, 2016

Class 8 over-the-road fleets can realistically expect fuel savings from low-viscosity oils, states a new report from Trucking Efficiency, an initiative under the North American Council for Freight Efficiency.

Fleets can expect fuel savings in the range of 0.5% - 1.5% by switching from 15W-40 to 5W/10W-30 engine oil, either CJ-4 or CK-4, the report found. The savings from switching to the fuel-efficient FA-4 variant, available after December 2016, can be expected to add a further 0.4–0.7% of increased fuel efficiency.

Fuel costs faced by the trucking industry have been extremely volatile over the past decade, so the report is designed to give an unbiased perspective of engine oil impact in an environment where fleets have more oil choices than ever before.

“While these efficiency gains are modest relative to some other technologies, this is one of the rare instances where an efficiency technology can be implemented across the entire fleet very quickly, does not require an upfront investment, and does not require any changes in operation or maintenance practices,” state the authors of the June 28 report.

Since 2003, fleets have invested in lower-viscosity lubricants with adoption rates for engine oils reaching 40% among the largest, most efficiency-conscious fleets. However, adoption rates are much lower in the industry as a whole at 20%, the report states.

A switch to lower-viscosity oil may also allow a fleet to consider an extended drain interval, which can help offset price premium.

The report also found that within the same viscosity grade, the base stock, whether mineral, synthetic, or a blend, does not directly affect fuel consumption.

All major North American engine OEMs have approved 5W/10W-30 engine oil for over-the-road applications, the study’s authors state.

 

DECISION GUIDE FOR LOW-VISCOSITY LUBRICANTS: 

DESCRIPTION OF FLEET AT PRESENT	SUGGESTED FLEET ACTION
Using 15W-40 mineral-based oil	Check with engine OEM(s) for approved 5W/10W-30 oil & work with oil supplier to find acceptable ROI assuming 0.5% fuel savings.
Using 15W-40 synthetic or synthetic-blend oil	Check with engine OEM(s) for approved 5W/10W-30 oil and switch. Fleet should see no significant cost increase.
Single-sourced engine OEM fleet using 5W/10W-30 oil	Work with engine OEM and oil supplier to accelerate backward compatibility of FA-4 to their application.
Multi-sourced engine OEM fleet using 5W/10W-30 oil	Consider isolating any FA-4 approved vehicles to a location where implementation of FA-4 oil could be practical.