There has been previous discussion of this topic here and I stumbled on a study that The Diesel Place ran on the topic. You might find it of interest. I know I did.

http://www.dieselplace.com/forum/forumdisplay.php?f=64

It's the sticky titled "Lubricity Additive Study Discussion".

Interesting! HFRR, BTW, is "High Frequency Reciprocating Rig"; I haven't seen where it's ever received an ASTM number. A micron is 1/1,000,000 of a meter, or 1/1,000 mm.

Anyway, there are some misconceptions, based on The Diesel Place Forum members' posts.

"Lubricity" is a term frequently flung about by folks (and we used it liberally when I was a Fuels and Lube Engineer), but it has no exact definition! It is usually used as a comparative term, such as "improved lubricity". A statement of "excellent lubricity" in a product is somewhat vapid (but when I peddled oil, I used it on occasion).

Emulsions/Emulsifiers: Bottom line is that emulsifiers should not be used in diesel fuel, and this is one VERY good reason not to add detergent-dispersant-containing motor oil. However, emulsions can be misunderstood. A simple emulsion is a substance in which insoluble ("immiscible") droplets of one ingredient are suspended in another. The latter is called the "continuous matrix" or "continuous phase". Taking the example of contemporary high-detergent motor oils, they contain additives to suspend the water in the oil, which is the continuous matrix. This minimizes (but doesn't fully eliminate*) the contact of water with internal engine parts, and when the engine warms up, those water droplets evaporate. Diesel fuel shouldn't get that hot, and there's no place for the water to go, anyway. Water retained/accumulated in aninjection system is not good, no matter how small the concentration.

* Motor oils do contain additives to ensure an oil coating of engine parts, so that what water droplets might otherwise contact engine parts, won't.

quote:

Originally posted by Rusty:
Interesting!

Emulsions/Emulsifiers: Bottom line is that emulsifiers should not be used in diesel fuel, and this is one VERY good reason not to add detergent-dispersant-containing motor oil. However, emulsions can be misunderstood. A simple emulsion is a substance in which insoluble ("immiscible") droplets of one ingredient are suspended in another. The latter is called the "continuous matrix" or "continuous phase". Taking the example of contemporary high-detergent motor oils, they contain additives to suspend the water in the oil, which is the continuous matrix. This minimizes (but doesn't fully eliminate*) the contact of water with internal engine parts, and when the engine warms up, those water droplets evaporate. Diesel fuel shouldn't get that hot, and there's no place for the water to go, anyway. Water retained/accumulated in aninjection system is not good, no matter how small the concentration.

Stable emulsion: Mayonnaise
less stable emulsion: Oil and Vinegar
water erodes diesel injectors, not real good for gasoline injectors with much lower pressure.
fwi