Pemex Diesel Fuel Update
There is some important new information to share regarding the availability of ULSD (Ultra Low Sulfur Diesel) in Mexico. Over the past month (February 2017) I kept pestering a half dozen public rel...
Forum Discussion
A minor clarification to a couple of things mentioned in some of the preceding posts:
1.
The emissions system used by vehicles designed for ULSD is not really a "bolt on". It is much more complicated than that. It involves an entire emissions programming set that monitors emissions and controls regeneration cycles, as well as fuel injection rates. Removing the system requires reprogramming of the ECM, which in itself is complicated and more easily done during manufacture than in an aftermarket environment.
2.
The emissions system doesn't remove the last 15ppm of sulfur. Sulfur compounds formed during combustion from this 15ppm are ignored by the emissions system and mostly pass out of the tailpipe. Anything above that concentration interferes with the functioning of the SCR (Selective Catalytic Reducer) which uses Diesel Exhaust Fluid (DEF) to reduce oxides of Nitrogen (NOX) in the exhaust. When higher sulfur fuels are used, sulfur compounds temporarily poison the catalyst surfaces until the next regeneration cycle burns the sulfur out of the system.
1.
The emissions system used by vehicles designed for ULSD is not really a "bolt on". It is much more complicated than that. It involves an entire emissions programming set that monitors emissions and controls regeneration cycles, as well as fuel injection rates. Removing the system requires reprogramming of the ECM, which in itself is complicated and more easily done during manufacture than in an aftermarket environment.
2.
The emissions system doesn't remove the last 15ppm of sulfur. Sulfur compounds formed during combustion from this 15ppm are ignored by the emissions system and mostly pass out of the tailpipe. Anything above that concentration interferes with the functioning of the SCR (Selective Catalytic Reducer) which uses Diesel Exhaust Fluid (DEF) to reduce oxides of Nitrogen (NOX) in the exhaust. When higher sulfur fuels are used, sulfur compounds temporarily poison the catalyst surfaces until the next regeneration cycle burns the sulfur out of the system.
