Dr. Robert Sutherland of Pennzoil isn't just one of the world's leading engine oil chemist
While writing this month's SEMA Action Network story (page 20) and taking a look at the 2016 CAFÉ standards for fleet-wide fuel economy that all the automakers are busily working toward meeting, it seemed fitting to dedicate this month's Tech Talk to an important but oftentimes overlooked piece of that puzzle: motor oil.
Whether you're aware of it or not, your engine's oil isn't just there as a lubricant designed to reduce friction on moving parts. It also plays an important role when it comes to fuel economy and emissions control, not to mention enabling advancements in engine design.
The latest minimum performance standard in passenger car motor oil, called ILSAC GF-5, is scheduled to take effect right about the time you read this (fall of 2010) and will be the factory fill for many 2011 model year engines. Starting in October of next year, GF-5 motor oil will be the required minimum standard for all gasoline engines (OEMs are always free to require more).
What are the ILSAC GF-5 specifications for motor oil, and how is it an improvement over ILSAC GF-4 spec oil? To answer these questions, I called Dr. Bob Sutherland, chief Pennzoil scientist at Shell Global Solutions and one of the world's leading motor oil chemists. Dr. Sutherland is also a member of the GF-5 negotiating team, where he helped define this new standard for motor oil.
According to Dr. Sutherland, "With respect to fuel economy, we always want more. For GF-5, we have a new fuel economy test, where we run the engine for 16 hours and make a fuel economy measurement. This is considered the fresh oil test. Then we age the oil [for 100 total hours or an estimated 4,000 to 6,000 miles] and redo the fuel economy test, which gives us an idea of how fuel economy changes as the oil ages. For GF-5 we have higher standards for both fresh oil fuel economy and aged oil fuel economy versus GF-4."
Sludge buildup is one of the performance-robbing elements that GF-5 oil is designed to red
In general, GF-5 lubricants deliver 1-2 percent improvements in fuel economy. As Dr. Sutherland pointed out, "Some of the fuel economy improvement is the result of using a lighter viscosity, but it's important to always run the specified viscosity level for your engine since it was carefully engineered to run it. If you use a lower than recommended viscosity oil in search of improved fuel economy, you run the risk of increased wear in critical areas of the engine."
ILSAC GF-5 isn't just about improved fuel economy, though. Improved oil robustness, where the oil better protects the engine from deposits and wear, has also been a focus of this new standard. According to Dr. Sutherland, "GF-5 robustness testing looks at sludge formation, varnish formation and resistance to carbon deposits on the pistons and rings. Moving from GF-4 to GF-5, we've really raised the bar on reducing sludge and piston deposits, since these are two of the most critical areas when it comes to engine performance. Sludge can cause blockages in oil flow to VVT devices, and it can also block the oil pickup screen or plug the oil filter, so reducing sludge is always a good thing. Limiting piston deposits as much as possible is also very important to overall engine operation, because as soon as deposits start to form on rings, ring grooves or ring lands, you really start to lose power and fuel economy. You lose the ring seal and as well as oil flow between the rings, which can lead to wear problems or even engine failure if a ring gets stuck and snaps. So keeping pistons clean is very important."