Philip wrote:

> Do reveal how higher combstion pressure and temperature result in more soot.
>

Simply re-read what I wrote, quoted below. Don't worry, I'll explain it
again when we get down there....

>
>>(and other undesirable combustion byproducts)
>
>
> The primary byproduct here is your vague reference to NOx?

I for one never said or implied a word about NOx.

>
>
>>being pushed past the rings into the LUBRICANT, even though the total soot
>>produced and sent out the tailpipe is much lower. Thus, poor
>>wording aside, the statement is correct in the context of soot loading
>>of the oil.
>
>
> Are you aware that NOx contaminates the lubricating oil? I am not. If
> less soot is being produced, then how is -more- soot being "pushed past the
> rings into the LUBRICANT"

Ring sealing technology has improved since 1960, but only very slightly
compared to improvements in other areas, such as fuel delivery
management and forced induction pressures. Combustion pressures tend to
be much higher with direct injection, hence there's a bit more blow-by.
So even though the combustion gasses may be cleaner, more volume (albeit
of cleaner gas) passes through the crankcase. Also, the higher pressures
result in higher piston underside temperatures, and that too stresses a
lubricating oil.