JHZR2
Staff member
Molakule, etc.:
I have a question regarding the design of the dispersant packages used in motor oils.
It seems to me that optimally, we would design an oil that would allow particles suspended in the oil to loosely aggregate/agglomerate, due to weak van der waals or DLVO type forces.
Under a slight amount of shear, such as occurs in an engine (many instances in an engine that are extremely smilar to any commonplace rheometer), these weakly aggregated particles would break apart, and cleanly flow through any narrow passages. However, in a large fluid body, such as the oil sump, the particles would be able to aggregate and thus plug themselves in the oil filter.
I have done numerous studies of interparticle interactions in situations such as stirred media mills, etc. Varying the surface chemistry to keep the particles permanently separated seems to me to almost be kind of dumb in an engine. It would be preferable to me to get the particles weakly aggregated, and then lodged in a full-flow/bypass filter system, where they won't get out.
Having dispersed fine particles permanently in the system seems to have the potential of being a problem. Of course, engine life and UOA show otherwise, but has thought ever been put into removing the particles rather than dispersing them? Seems oils could last a lot longer this way in situations like diesels, where soot is the limiting factor.
JMH
I have a question regarding the design of the dispersant packages used in motor oils.
It seems to me that optimally, we would design an oil that would allow particles suspended in the oil to loosely aggregate/agglomerate, due to weak van der waals or DLVO type forces.
Under a slight amount of shear, such as occurs in an engine (many instances in an engine that are extremely smilar to any commonplace rheometer), these weakly aggregated particles would break apart, and cleanly flow through any narrow passages. However, in a large fluid body, such as the oil sump, the particles would be able to aggregate and thus plug themselves in the oil filter.
I have done numerous studies of interparticle interactions in situations such as stirred media mills, etc. Varying the surface chemistry to keep the particles permanently separated seems to me to almost be kind of dumb in an engine. It would be preferable to me to get the particles weakly aggregated, and then lodged in a full-flow/bypass filter system, where they won't get out.
Having dispersed fine particles permanently in the system seems to have the potential of being a problem. Of course, engine life and UOA show otherwise, but has thought ever been put into removing the particles rather than dispersing them? Seems oils could last a lot longer this way in situations like diesels, where soot is the limiting factor.
JMH