Quote:
Originally Posted by brando1985
I appreciate your input, but question your hypothesis. I'm curious how the quality of diesel contributes to CBU in the intake / intake ports. The fuel never reaches those areas, unless it's implied that increased soot is the bi-product of lessor quality diesel, hence increasing the chances of CBU via EGR?
Further, as we all know, the N54 guys are battling CBU as well. Since those engines don't have to combat soot, one would suspect that while the prevention of EGR is good for our diesels, it's only half the equation. To completely eliminate the chances of CBU of any kind, one needs to eliminate the EGR, and take steps to reduce oil from finding its way into the intake manifold, correct?
Thanks,
Brando
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Understanding that the oil from different regions has different levels of paraffins and variations in types of hydrocarbon molecules, both gasoline and diesel will have different composition to a certain extent from different types of crude and refining/hydrocracking techniques. The chemical composition of the soot itself may also matter and be a function of the fuel composition, I don't know.
If you google direct injection and CBU, the scientific papers, mostly from SAE, imply fuel composition and/or additives in their conclusions as preventing or causing deposit formation is mentioned. Please see attached files.
ACEA Position on Metal Based Fuel Additives.pdf
IDID Quigley TAE Esslingen 2011 .pdf
The Use of Ferrocene Additives to Reduce Carbon Build Up in Diesel Based Internal Combustion Eng.pdf
The importance of diesel fuel cleanliness and contamination is also part of the discussion in this chapter:
Diesel fuels.pdf
But this doesn't refute the role, in general, of engine management and EGR design:
EGR Applied Energy August_2011.pdf
I'm sure the same can be said for gasoline direct injection. I don't have any studies on the gasoline side, being a diesel head since 1997.....
PL