Competing lubrication performance

Now, in the previous section, we talked about some additives. So, if we use ester as the base oil and add a lot of additives, we can make the ideal oil, right? I don't know if there are those who think that, but you can guess what I mean by the title. Anti-wear agents, extreme pressure agents, friction modifiers, base oils with strong polarity, and so on. All of these work by sticking to or compounding with metal surfaces. So what happens if there is a large amount of each of these? Each will interfere with the other and reduce the effectiveness of the other. This is what is called "competition. What can we do to eliminate competition? First, we cannot eliminate conflicts completely. It is up to the oil blender to maximize the effect of the additives with the least waste while they are competing with each other. The theory is to minimize the polarity of the base oil as much as possible. If the polarity of the base oil itself is too strong, the additives will be less effective. The non-polar base oils are mineral oil and PAO. Mineral oil, especially VHVI, which contains few impurities, is widely used in recent years because it is effective as an additive even in small quantities and its cost is relatively low. It is also very easy to use as a base oil because it has little effect on rubber (although it swells it very slightly). PAO, on the other hand, has the advantage of reducing the amount of viscosity index improvers and flow point reducers used because of the high viscosity index of the base oil itself. On the other hand, PAO cannot be used as a stand-alone oil because of its low compatibility with additives and because it causes rubber to shrink. This is because engine oil requires a large amount of additives, including antioxidants, to be dissolved in it. Therefore, it must be combined with mineral oil and AN to make a well-balanced oil. Now I digress, to reduce the impact of competition. The next approach is from additives. Have you ever seen a test or demonstration where a piece of metal is pressed against a rotating rod to measure friction and wear? That test is called the chimken test, and the one with high extreme pressure has an advantage. If you have seen a tester that applies high pressure, which is impossible in an actual engine, and still runs well, and you think, "Wow, this is amazing, the engine runs smoothly now! Of course, extreme pressure is added to prepare the engine for high pressure when the oil film runs out. However, high extreme pressure performance means that other performance is compromised. In a real engine, the bearings are designed to be wider where they are subjected to high pressure and to disperse the pressure. In a normal engine, extreme pressure agents do not play a major role. Oil with excellent extreme pressure performance is unbalanced when viewed as an engine oil. The approach from additives is to determine the performance required for the engine, confirm it through comprehensive tests including actual driving, and mix additives in a suitable balance. Oh, yes, there is one more thing I wanted to tell you about the chimken test. However, in the Chimken test demonstration, you are using cold, fresh oil. This is normal oil for comparison," you say, "and this is normal oil for comparison," without allowing the additives in the oil to be demonstrated. Whoever came up with this demonstration is quite a badass. I hope no one will fall for it in the future.
*This is not to say that the Chimken test is meaningless, but rather that if the minimum standard is met, even if it has more extreme pressure, the effect is limited. Extreme pressure performance is important when the lubrication layer is destroyed for any reason.
There is also a high-speed chimken test, in which a test is conducted under a low load and high speed, similar to actual lubrication conditions.

Share this post

← Older Post Newer Post →