Emission control regulations are changing, and the emphasis is on controlling greenhouse gases. Despite recent management upheaval at the influential United States Environmental Protection Agency, it appears the agency is committed to a phased approach to reducing emissions.

In 2011, President Barack Obamas administration negotiated new rules with U.S. automakers that sought to double average fleet-wide fuel efficiency to 54.5 miles per gallon (23.17 kilometers per liter) by 2025. However, President Donald Trump wants to review U.S. vehicle fuel-efficiency standards from 2022-2025, reopening the process ahead of a previously agreed April 2018 deadline.

Removed from the politics, lubricant additive companies have been assessing new trends and technologies that will shape the lubrication of heavy-duty diesel engines beyond 2018. In Europe, the evolution of heavy-duty fleets has resulted in a growing market for lower sulfated ash lubricants that comply with ACEA E6 SAPS (sulfated ash, phosphorus and sulfur) limits. According to Bhaskar Mukherjee, Chevron Oronites market manager for Europe, Africa and the Middle East, fuel economy lubricants are a relatively inexpensive but a high-impact way to reduce friction losses and enhance fuel economy compared with other engine strategies.

Move to Zero Emissions

Speaking at the Base Oils and Lubes Middle East conference in May in Dubai, Mukherjee said consumer choice is increasingly expected to favor energy-conserving lubricants made from the most widely available base stocks that deliver wear control and fuel economy targets. He believes there is a great deal of harmonization in emission control technology, particularly among Europe, the US and Japan.

Most of the current technologies are oriented toward zero-emission diesel engines and reductions in particulate matter and nitrous oxide, he said. Lubricant specifications have also evolved and include ACEA E6 and E9 in Europe, API CK-4 and FA-4 in the U.S. and Japans new JASO DH-2F standard.

In the next decade, the focus for original equipment manufacturers will be on cost of ownership and resource conservation. One of the facilitators will be low- viscosity lubricants. You burn less fuel if you overcome friction. Phase two of the U.S. EPA and National Highway Traffic Safety Administrations carbon dioxide and fuel consumption standards are due to be implemented from 2018.

The targets, according to Mukherjee, are challenging with reductions of almost 20 percent and more in some classes of heavy-duty diesel engines. Although phase two is currently EPA policy, its roll-out hangs in the balance and may be overturned.

Engine and Truck Technology

Future developments in engines will require lubricant performance beyond todays technology. Under EPA phase one, existing engine platforms achieved significant performance enhancements. These include combustion improvements, higher fuel injection pressures, smaller displacement, friction reduction and turbocharging, as well as selective catalytic reduction and exhaust gas recirculation. Next-generation engine platforms will likely include a greater number of technologies Mukherjee believes. There is a trend toward downsizing of engines in the passenger car segment, and it will be evident in the heavy-duty space, too, said Mukherjee.

Technological evolution is about improving engine efficiency, and future technologies might include variable compression ratio and valve timing, waste heat recovery, dual-stage turbocharging, parent-bore engines (i.e., without the replaceable piston liners commonly found in heavy-duty diesel engines) and low-temperature combustion. The consequence of these technological advances is increased thermal load on lubricants, a major concern for OEMs. A thin film when heated becomes thinner, and although a function of the viscosity index, there is a question of whether the lubricant will control wear, Mukherjee explained.

The dilemma over lubricant durability raises questions about cost of ownership for fleet owners, which is particularly pertinent in the Middle East where high ambient temperatures and dust ingress increase friction in engines. This situation becomes more of a concern as the region reduces its dependence on high-viscosity API Group I base oils, which have typified the market for so long.

Oronite has conducted tests demonstrating that lower-viscosity engine oils reduce fuel consumption when used in conjunction with a crafted additive package. The tests were conducted in a 5.9-liter Cummins ISB run on the World Harmonized Transient Cycle using an API CJ-4 additive package blended into an SAE 5W-20 or 5W-30 oil. Polymer content was varied to meet a range of high temperature high shear (HTHS) and kinematic viscosities. Reducing HTHS from 4.2 to 3.0 centiPoise produced a 1.2 percent fuel economy benefit.

It indicates that when you use a low-viscosity lubricant, you get lower energy consumption and, therefore, you get savings, Mukherjee said. However, the savings need to be viewed in the context of the different operating regimes of heavy-duty diesel engines.

Concerns over thermal load prompted Volvo to evaluate advanced lubricants and their impact on performance and fuel economy. The company was seeking a product that exhibited less of a viscosity increase and better oxidation control. The results showed that most API CJ-4/E9 oils would not pass the Mack T-13 oxidation test.

Another prominent OEM, Daimler, has upgraded its specifications with an emphasis on durability and scuffing protection. To comply with its recent 228.51 upgrade Daimler requires a higher lubricant specification comparable in performance to ACEA E6/7 and API CK-4. The German OEM has also increased the wear control limits on the OM 501 LA and OM 646 LA engine. Setting such standards dictates that claims for fuel economy must be tangible and measurable.

Middle East Outlook

For years, governments in the Middle East have heavily subsidized fuel prices, but in the wake of the fall in crude prices those subsidies, in varying degrees, are being rolled back. While it remains to be seen whether Gulf policymakers continue to hack away at subsidies, Mukherjee contended that operators can still realize value in the Middle East where fuel costs are low and subsidies exist. An Oronite study in the region demonstrated that operators can capture real savings if a lubricant can deliver just 1 percent fuel economy improvement.

Lubricant drain intervals in the Middle East are low, and Mukherjee conceded that only a modest change in habits is expected in the use of fuel economy lubricants. But using higher-specification lubricants makes it possible to double drain interval to 30,000 km from the regions typical interval of 15,000 km. This would generate savings of around U.S. $88 per oil change. It may appear meager, but it is a start. And when you apply that to a fleet, the savings can be substantial, he said. Of course, actual cost savings depend on several factors, including fleet composition and operating regimes of heavy-duty diesel engines.

Market Direction

Understanding how the market is evolving is fundamental to the additive business, and a recent review by Oronite provides a glimpse of the direction being taken in Europe. The region comprises a highway fleet of around 8 million trucks and is key battleground for low viscosity lubricants.

We project that by 2026, we may see a 25 percent market share for low-viscosity lubricants, lower than 3.5-cP HTHS. But a substantial proportion – 70 percent or more – of low-emission diesel engine lubricants will have some degree of fuel economy ability, Mukherjee said.

There is little doubt the OEMs focus in the next few years will be on reducing greenhouse gases. Mukherjee believes the use of high sulfated ash oils will decline, and consumer choice will center around fuel economy lubricants possessing long drain intervals. These will be the essential components to deliver the cost-effective efficiency improvements the market demands. Technological progress is such that todays engines possess enough development potential to meet future emission and fuel economy regulations. Nevertheless, changes in engine design have increased thermal loads on lubricants but the desire for fuel economy must not come at the expense of resilience. OEMs will not sacrifice durability for improved fuel economy, particularly as far cost of ownership is concerned, Mukherjee said.

Diesel-gate Permeates

With the industry-wide preoccupation on future technological developments, it is hard to escape the long shadow of the emissions scandal of 2015, known as diesel-gate. There is no suggestion the heavy-duty diesel engine market has been compromised by the fallout in the passenger market scandal that has engulfed several automakers, most notably Volkswagen, which was caught by the EPA falsifying emissions readings during lab testing. However, the discussion about diesel nitrogen oxide (NOx) emissions is a wider industry worry.

The backlash against the efficiency of diesel technology is plain to see, and according to some analysts it borders on existential. That is despite diesels proven durability and the technological prowess of selective catalytic reduction in removing NOx emissions.

But the debate is raging. A newly released study by the International Council on Clean Transportation found diesel vehicles in major markets produce over 50 percent more NOx than official certification limits indicate. The council urges more stringent tailpipe emission standards that it estimates could prevent 174,000 premature deaths annually by 2040.

The ICCT clearly has the heavy-duty market in its sights. Heavy-duty vehicles – commercial trucks and buses – were by far the largest contributors worldwide, accounting for 76 percent of the total excess NOx emissions. And just five markets – Brazil, China, the European Union, India, and the U.S. – produced 90 percent of that, said Josh Miller, researcher at the council and co-lead author of the study.

The momentum from regulators for a quick solution to the problem is building, adding further pressure to the already complex research confronting the industry. The vital role lubricant technology will play in sustaining the heavy duty diesel engine market is increasingly apparent. What form that takes and how it is manifested may require a more collaborative approach than has been the current norm.