By Dan Arcy, OEM Technical Manager, Shell Lubricants
The American Petroleum Institute (API), working with engine manufacturers and oil makers, has completed redesigning two new heavy-duty engine oil specifications. Nearly a decade has passed since the last diesel engine oil category, API CJ-4, was developed and major changes are required.
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.
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 lower CO2, more fuel-efficient diesel engines, they need a new generation of higher-performing diesel engine oils to protect them.
New Oil Classifications Tackle Emerging Diesel Engine Technology
Evolution to Revolution
Heavy-duty diesel engine designs have evolved substantially over the last 40 years. This evolution has been driven by emissions 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 aftertreatment 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 emissions and NHTSA 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) while they were being developed.
The new specifications have been finalized and two new oils performance standards were developed with first licensing on December 1, 2016. They will replace the current CJ-4 heavy-duty oils.
- API CK-4 oils will replace today’s CJ-4 lubricants and will be completely backwards compatible with all current on- and off- road vehicles. They will be designed with improved oxidation resistance, shear stability and aeration control.
- API FA-4 oils will meet these new requirements and include lower viscosity grades designed for next-generation on-road diesel engines to help maximize fuel economy without sacrificing engine protection. These oils are expected to have limited backwards compatibility because some older engines were not designed to operate with lower viscosity grades
These new engine oil requirements, especially for FA-4, 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. CK-4 and FA-4 specifications will continue to use many of the current tests, but some of these tests will have more stringent limits. Two new tests have been 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. New CK-4 and FA-4 oils will be licensed on December 1, 2016.
Shell Lubricants is playing a leading role in the development and testing of the next generation of low-viscosity oils through more than 40 million miles of real-world testing and has demonstrated the performance of its next-generation, low‑viscosity oil formulation technology. New Shell ROTELLA T4 15W-40 Triple Protection and Shell ROTELLA T5 10W-30 Synthetic Blend have been developed to meet the new API CK-4 service category for diesel engine oil and are available now.
What New Specifications May Mean for Your Fleet
API licensed oils are used for on- and off-highway applications. The same goes for the new oils as they will be valid for transport, agriculture, construction, mining and even diesel pickup applications. You will be able to expect improved protection and performance, even in the tough terrain and harsh conditions your off-highway vehicles face on a daily basis. With on-highway diesel emission legislation generally leading off-highway requirements by several years, on-highway engines are generally used to develop engine tests. Engine manufacturers are still determining whether off-highway engines will use FA-4 oils.
Visit Rotella.com for more information about the new oil specifications - topics include the fundamentals of CK-4 and FA-4, approaching changes, testing updates, and how the new category is expected to affect new, current and older engines when it replaces API CJ-4 engine oils.
About Dan Arcy: Arcy works closely with OEMs on new product testing and development of lubricants and new lubricant specifications. He also works extensively with Shell’s on- and off-highway field testing programs. He served as chairman of the New Category Development Team (NCDT) and was responsible for leading the NCDT in defining the PC-11 performance standard for the next-generation heavy-duty engine oils.
