Benefits of Low Sulphur Diesel

[Watty]

Here in South Africa the sulphur content of diesel has been set via legislation in Jan 2006 to either 0.05% or 0.005% (the 50 ppm is locally known as ULS diesel - ultra low sulphur). Previously sulphur levels could not be more than 0.3%. Apart from the obvious environmental issues and less wear and tear within the enjine, filters, etc., it would be interesting to know if there is any real:-

1. fuel consumption benefits using low sulphur diesel?
2. improvement in power

Any experiences / views from other CRD owners?

 

[Silver Streak]

Diesel with low sulphur is considered more enviromentally friendly. It used to be the all diesel and gasoline as well were low sulphur, back before the `73 OPEC oil embargo. Back then crude oil that contained any appreciable amount of sulphur was only used for Bunker C fuel oil. Bunker C was burned in power plants mostly, and ocean going ships boilers and so forth. The enviromentalists of the `60s went crazy and began the hullabaloo claiming Acid Rain was the boogey man caused by burning fuel oils made using high sulphur crude oil stocks. The public utilities saw low sulpur fuels as the panacea to get them out of the public eye so to speak. This made bunker C only good for ocean going ships and the rare boiler now and again. The Arab oil embargo of `73 caused oil companies to begin selling diesels made from high sulpur crude oils for the general consumption of industry. The result was many failed engine bearings due to the high acid content left in motor oil from engine blow-by.
Oil industry groups like the API (american petroleum institute) instituted new standards for motor oils that included protection for corrosives left from burning motor fuels that contained too much sulphur. In the US here, this was when API service CC or maybe it was CD came about for diesel engine oils. Basically they added something like alka-seltzer to the oil in small quantities to counter act the acid left from the sulphur fuels. Crude oil stocks from Venezuala and Nigeria for instance, are high sulphur crude stocks, and therefore diesels made from these stocks are high sulphur. The refinery that processes these oils has to be special as well, due to the differences in this base stock. This is why Chavez of Venezuala, though he loudly proclaims he will sell his oil elsewhere, only the US has the capaciaty to handle large quantities of high sulphur crude oils.
Low sulphur diesels don't effect the water cooled EGR valves nearly as adversely as higher sulphur diesels. It is only in the US that i am aware of that we have laws making Nitrous Oxides (NOX) emissions the boogey man. In Europe and elsewhere they allow higher nox emissions, but consider any fuel containing high sulphur content to be the boogey man, because they figure it contributes to acid rain. So it is basically all about enviromental laws now a-days; however it was originally very bad for your engine. Thankfully the lubrication oil producers countered this very effectively in the `70s, and now most people don't even remember it. To be a good little enviromentalist today of course, you have to tout the awful effects of high sulphur fuels, even if you don't have a clue what the hell you are talking about.

Silver Streak

 

[m0th]

But doesn't using ULSD allow you to have better catalytic converters and other pollution reduction stuff since they won't get damaged by the sulphur, hence less NOx and particulates.

 

[Watty]

Here is the view from a local science magazine:

Sulphur in diesel contributes towards the formation of the acid rain causing and lung-damaging pollutant, sulphur dioxide. It is also directly related to the amount of soot formation in a diesel engine and hence also the amount of particulates introduced into the atmosphere. In addition to polluting the atmosphere, these chemicals pollute the vehicle's engine itself: causing changes in the lubricating oil composition as well as the poisoning of the exhaust treatment catalysts, degrading their performance. In the long term, these chemical changes reduce the efficiency of the oil, meaning a need for frequent oil changes. Low sulphur fuels extend the life-span of the oil as it is not degraded as quickly. Longer oil-change intervals translate to direct savings of time and resources.

Benefits of ULS Diesel are

-improved engine performance;
-longer engine life;
-extended oil change intervals;
-and a cleaner environment.

The savings resulting from using better fuel will save a pickup truck/bakkie owner about R4500 (US$370) every 30000km. The use of low sulphur fuel in combination with a used oil monitoring programme increases the oil change interval from 7500km to 15000km (For vehicle's still under warrantee the marketer must be consulted before drain intervals are extended). For a small business with one vehicle, this represents a 50% reduction in days lost to vehicle maintenance.

In some ways this new fuel will be like a better bottle of wine for a car - it causes less wear and tear than plonk, the headache will be much lighter than with plonk, the mood better and the bouquet terrific.