A major oil technology change is heading for the trucking industry and it is a major shift in lubricant technology, the lifeblood of our prime movers. Diesel Workshop looks at the tests the new oils have to undergo. API CK-4 and FA-4 present tough challenges for the next generation of diesel engine oils and how they must perform, particularly in advanced modern engines. Three tests in particular define these performance challenges.
The oxidation control test looks at oxidation, which is a chemical reaction of oil with oxygen (from air) which significantly deteriorates engine oils over time. It is accelerated by high stress operation conditions such as the high temperatures we see in modern engines. Oxidation control is becoming increasingly important, as advanced heavy duty engines are designed to run hotter in the drive for higher performance and efficiency. Oxidation leads to increasing oil viscosity and deposit formation, which results in reduced ability to flow, thus decreasing engine protection and negatively impacting engine fuel efficiency.
The CK-4 diesel engine oils are blended to deliver outstanding oxidation resistance to meet the demands of hard working equipment in Australia.
The aeration control test is also important, aeration or foaming is a physical process in which small bubbles of air as foam become entrapped in the lubricant. Aeration directly affects the intended lubrication properties of oil. A high level of entrapped air will degrade the ability of the oil film to protect engine parts, potentially causing engine wear and ultimately meaning greater costs for operators.
The CK-4 engine oils will meet or exceed the new category test for aeration control, to deliver higher ever levels of engine protection.
There is also the shear stability test necessary because multigrade engine oils are formulated with viscosity modifiers, additives which control oil viscosity under different operating temperatures. Under stress, these molecules may ‘shear’, affecting their ability to control viscosity.
Shear stability is a measure of the ability of an oil to stay in SAE viscosity grade i.e. SAE 30 stays as an SAE 30 after repeated use. The viscosity specs of any engine oil are precisely matched to the application and operating conditions it is recommended for. Shearing of the viscosity modifiers means the oil can become thinner and less protective, i.e. an SAE 30 grade could drop down to SAE 20 leading to compromised engine protection.
The API FA-4 engine oils are formulated with a unique viscosity modifier which significantly improves the oil’s shear stability, for new levels of stay-in-grade performance, and better protection for the modern heavy duty diesel engines.