The American Petroleum Institute (API), working with engine manufacturers and oil makers, is completely redesigning heavy-duty engine oil specifications. Nearly a decade has passed since the last API diesel engine oil category, CJ-4, was developed.
“The current CJ-4 standard has lasted well beyond the life of the typical engine category. Some of the engine tests required to qualify an oil are no longer available or no longer relevant to next-generation engines,” according to Dan Arcy, chair, New Category Development Team, API, and global OEM technical manager, Shell Lubricants.
Oil technology and engine technology go hand in hand. Changing regulatory limits challenge engine manufacturers to reduce emissions. As engine manufacturers begin to create a new generation of cleaner, more fuel-efficient diesel engines, they need a new generation of higher-performing diesel engine oils to protect them.
EVOLUTION TO REVOLUTION
Heavy-duty diesel engine designs have evolved substantially over the last 40 years. This evolution has been driven by emission legislation and customers’ requirements for efficiency and reliability. There has been significant progress. For example, high pressure, common-rail injection systems are now widely used to improve combustion efficiency; advances in turbocharger technology have increased specific power output; and exhaust gas recirculation and after treatment devices, such as diesel particulate filters and selective catalytic reduction, have curbed harmful emissions of oxides of nitrogen and particulate matter (i.e., soot).
Despite this progress, recent regulations coupled with customers’ desires to reduce the total cost of ownership are making fuel economy the most critical driver for engine manufacturers. Advanced technologies and materials, and new operating conditions, such as higher operating temperatures, continue to improve engine efficiency.
Engine changes place more stress on the oil, which has to lubricate, cool, clean, and protect over long oil-drain intervals. The vehicle industry is starting to recognize that oil can help to achieve an engine’s full potential for fuel economy without compromising hardware durability. As engine manufacturers create cleaner, more fuel-efficient diesel engines, they will need a new generation of higher-performing diesel engine oils to protect them.
DEFINING THE CATEGORY
Engines have changed considerably since CJ-4 was introduced. They have improved fuel consumption and increased power outputs. New EPA and NHTSA emission legislation scheduled for diesel-powered commercial transport vehicles in 2017 requires significant improvements in fuel consumption that will help to reduce carbon dioxide emissions. These fuel consumption improvements depend on vehicle class, type, and size, and include specific improvements for medium and heavy-duty engines. This has created the need for a new category of lubricant specifications, collectively called Proposed Category 11 (PC-11).
These oils, targeted for licensing in December 2016, will eventually replace the current CJ-4 heavy-duty oils. The API will introduce two types of heavy-duty diesel oil as part of PC-11:

  • PC-11A (CK-4) oils will replace today’s lubricants and will be completely backwards compatible with all current vehicles. They will be designed with improved oxidation resistance, shear stability, and aeration control. (The name API CK-4 is the current proposed name for the category.)
  • PC-11B (FA-4) oils will meet these new requirements and include lower viscosity grades designed for next-generation diesel engines to help maximize fuel economy without sacrificing engine protection. These oils will have limited backwards compatibility because some older engines were not designed to operate with lower viscosity grades. (The name API FA-4 is the current proposed name for the category. The term FA-4 will differentiate them from API CK-4 oils. The names API CK-4 and API FA-4 could still change, depending on comments from the API Lubricants Group.)

These new engine oil requirements, especially for PC-11B, are a major change in the industry’s approach to heavy-duty oil specifications. Oil producers will need to continue to deliver excellent wear protection and cleanliness—two factors that help to drive down customers’ maintenance costs and prolong engine life.
NEW AND UPDATED TESTS
A major part of designing an oil specification is defining a set of rigorous tests that each oil formulation must pass before it goes on sale. PC-11 specifications will continue to use many of the current tests, but some of these tests will have more stringent limits. Two new tests will be introduced to ensure that next-generation oils can cope with the oxidation stability and aeration control needs of modern technology. Both tests are designed to ensure that the new oils will be able to protect new and older engines operating under more severe conditions.
Shell Lubricants is playing a leading role in the development and testing of the next generation of low-viscosity oils through more than 20 million miles of real-world testing and has demonstrated the performance of its next-generation, low‑viscosity oil formulation technology.
WHAT PC-11 MAY MEAN FOR YOUR VEHICLES AND EQUIPMENT
With on-highway diesel emission legislation generally leading off-highway requirements by several years, on-highway engines are generally used to develop engine tests. However, API licensed oils are used for on- and off-highway applications. The same goes for PC-11 oils as they will be valid for transport, agriculture, construction, mining, and even diesel pickup applications. Engine manufacturers are still determining whether off-highway engines wi\ll use PC-11B oils. You will be able to expect improved protection and performance, even in with the tough terrain and harsh conditions your off-highway vehicles face on a daily basis.
PC-11 ENGINE OIL UPDATES
New PC-11 oils should be available in late 2016. The Shell Rotella brand launched a website called WhatIsPC-11.com to help educate and inform people about PC-11. The website will be a resource for topics such as the fundamentals of PC-11, impending changes, testing updates, and how it is expected to affect new, current, and older engines when the category replaces API CJ-4 engine oils by 2017. ■
For More Information: For more information about new PC-11 oils, be sure to check out the website www.whatispc-11.com, a site created by Shell Rotella as a resource.
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Modern Contractor Solutions, August 2015
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