Just when the trucking industry was growing accustom to CJ-4 oil, the National Highway Traffic Safety Administration released new greenhouse gas (GHG) regulations and required fuel economy gains for on-highway medium and heavy duty trucks. Engine and truck manufacturers know that to help meet these new requirements with the modern diesel engine they must reduce oil viscosity, thereby reducing fuel consumption.
A new proposed classification of oil called PC-11 appears to be the answer that the engine manufacturers need to meet the requirements.
Proposed Category 11 (PC-11) likely will be the American Petroleum Institute (API) replacement for CJ-4 and for good reasons. This new oil category provides better oxidation and shear stability, and it enhances overall engine performance and durability.
It is probable that the industry will see two categories of PC-11: one for modern engines and one to be backward compatible for older engines. The older designation will likely be a replacement for 15W-40 oils while the newer PC-11 will mainly be available in 10W-30 weights or lighter. This lighter oil must be able to endure extreme heat while helping improve fuel economy and emissions.
The new U.S. EPA fuel economy requirement is not so cut and dry. In fact, the OEM requirement could be from a 6 percent to 20 percent improvement, depending on the type of vehicle operated. This means that the new oil must be adaptable to multiple engine platforms and demands with similar hardware as exist on the engines today.
OIL FILTRATION
Perhaps the out-of-sight critical system that will be integral to the success of this lighter, more resilient oil is the oil filtration system. The oil filter will be required to filter this lighter oil without creating more friction and negatively impacting fuel economy. As the viscosity of the oil goes down, so does the oil pressure.
To further exacerbate the issue, engine manufacturers say we will likely see an increase of 10 degrees in engine temperature.
As oil travels throughout the engine, it is churning and being filled with air bubbles which are not good for lubricating critical parts such as rod and main bearings. The PC-11 oil must resist the tendency to aerate and have the ability to release any air that will be produced.
Engine manufacturers must conduct rigorous tests to ensure the filtration systems can adequately handle the new engine designs and requirements.
2018
I believe most engine manufacturers, by 2018, will fill their engines from the factory with the updated PC-11 to be in compliance with the new greenhouse gas standards and be prepared for the harsher operating environment of the modern diesel engine. Fleets are hoping for lower maintenance costs and higher vehicle uptime as a result of using this high-performing oil by allowing them to extend oil drain intervals.
Of course, customizing engine oil change intervals should never be attempted without applying tried and true techniques, such as the application of the vehicle, average miles per year and an engine manufacturer’s recommendation.
These are very exciting and challenging times as we understand the diesel engines of today are increasingly more complex and, in some cases, will require a higher skilled technician just to perform the “basics.”
Homer S. Hogg is the manager of technical development for TA and Petro Stopping Centers (www.ta-petro.com). It is a leading full-service travel center company in the U.S. serving professional drivers and motorists alike, offering diesel and gasoline fueling services, full- and quick-service restaurants, 24-hour convenience stores, heavy truck maintenance services, emergency roadside, service, truck parking reservations and many other services.
