Originally Posted By: Ducked
That graph has some features I've never understood.
What's the X-axis, and how do they get away with publishing a graph without it labelled (assuming they have editors who know their arse from their elbow)?
I'd guess OCI (time) would make sense. A plot of TBN against TAN would too.
Why that clear "wedge" under the TBN line, the bit with no TAN points? (The TBN line is perhaps "theoretical". There's no way that's real raw data, though I suppose it COULD be a fitted curve).
I think I'll send an email to the organization that was listed as the author for that article.
The x (horizontal) axis could be time, or miles after the most recent oil change. On the other hand, it might not refer to anything at all. The "real raw data" would be the blue dots, which represent a reading from a truck's TAN. The higher the TAN, the higher up (y axis) that dot is placed. But what determines the x axis is simply what the TBN is at the time of the reading. I read that chart as, "When TBN is this much, TAN is that much." The TBN line might simply be portrayed to look like a typical TBN trajectory in an individual vehicle.
That graph has some features I've never understood.
What's the X-axis, and how do they get away with publishing a graph without it labelled (assuming they have editors who know their arse from their elbow)?
I'd guess OCI (time) would make sense. A plot of TBN against TAN would too.
Why that clear "wedge" under the TBN line, the bit with no TAN points? (The TBN line is perhaps "theoretical". There's no way that's real raw data, though I suppose it COULD be a fitted curve).
I think I'll send an email to the organization that was listed as the author for that article.
The x (horizontal) axis could be time, or miles after the most recent oil change. On the other hand, it might not refer to anything at all. The "real raw data" would be the blue dots, which represent a reading from a truck's TAN. The higher the TAN, the higher up (y axis) that dot is placed. But what determines the x axis is simply what the TBN is at the time of the reading. I read that chart as, "When TBN is this much, TAN is that much." The TBN line might simply be portrayed to look like a typical TBN trajectory in an individual vehicle.