Quote:
Originally Posted by LUVMBDiesels
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Tips for Diesel Owners
Diesel Fuel In the '90s Diesel fuel quality is declining throughout the world, and we expect this trend to continue. In fact, a recent survey suggests that 70% of diesel fuel sold at service stations does not meet the Society of Automotive Engineers' (SAE) standard for diesel fuel lubricity. The three leading factors affecting fuel are:- Crude oil sources
- Refining techniques, and
- Blending techniques ..."
I have been saying this for some time now. I always use Lucas Fuel treatment and Diesel Kleen in my car. I get MUCH better milage ~4-5mpg than when I do without them.
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While this was true to a point for a while, it was a function of allowable sulfur and how refiners aligned blend pools and stocks to maximize profit. With ULSD, fuel quality has increased. The reason why is that the aromatic-bound sulfurs, generally benzothiophene type molecules, are very difficult to process.
We use hydrodesulfurization to upgrade diesel cut fuel stocks to be ultra-low sulfur. This involves high temperature and high pressure hydrogen being reacted. The issue is that the reaction is not selective to the sulfur species, and so the reaction tends to open aromatic rings and force reconstruction of the compounds before the sulfur is accessible and reacted.
The byproduct is a better fuel with less aromatics (an issue for seal swell and lubricity though), and higher cetane.