Have you ever looked at the sticker that states ULTRA-LOW SULFUR HIGHWAY DIESEL (ULSD) when you fill up your truck at the pump? What does this mean for you and your diesel truck?
Refineries have been forced to remove the sulfur from the diesel. In 1993, the Government started to work on bills that would lower the sulfur level of diesel fuel. Then in 2007, all on-highway diesel vehicles were required to run the ULSD, which reduced sulfur down to 15 ppm. One of the primary reasons to reduce sulfur was to reduce the emissions produced by diesel engines. Sulfur has been linked to one of the major sources of smog-causing air pollutants. The lower sulfur was also required to protect the new emissions equipment installed on diesel vehicles from 2007 and up.
What does this mean for those who use this diesel fuel?
There is a lot of confusion around how this sulfur reduction affects the diesel fuels today. One of these topics revolve around the lubricity of today’s fuel. The correlation between sulfur and lubricity is often confused in that sulfur is the lubricity on diesel fuel. Some think that because the sulfur is being removed then so is the lubricity. Well this is partly true, but not in the way that most think. Lubricity is an important and required element in diesel fuel. Diesel fuel components need lubrication so that there is no metal to metal contact. Some of these components that have very tight tolerances and require significant lubrication are fuel pumps and injectors. If there is not enough lubricity in the fuel, these components will wear and eventually fail.
What’s the connection between sulfur and lubricity? In order to reduce the sulfur content of diesel fuel, refineries use a process called desulfurization to remove the sulfur. Unfortunately, during this desulfurization process there are critical components that are destroyed. Some of these components are what make up the lubricity in diesel fuel. So what you get is a fuel that is satisfactorily low in sulfur, but also unsatisfactorily low in lubricity.
Once the EPA started to realize this correlation between low sulfur and low lubricity, they launched a task force to include lubricity requirements. In 2005, lubricity standards were included in the ASTM D975 (regulation code) that included an established testing method for determining the required amount of lubrication the fuel has. So now fuel-regulating agencies are mandating that all No. 2 ULSD diesel fuel must comply with lubricity requirements. Engine manufacturers will also void warranty if the fuel used is not compliant with this lubricity limit. In order to meet these requirements, refineries are injecting additives into the fuel at distribution sites. Each one of the gas stations or fuel distributors is responsible to determine if these additives are meeting the standard or not. So this is where there is some possible error in the quality of fuel you are getting at the pump.
What can you do to make sure you are getting the best quality fuel? For starters, make sure to buy your fuel from a quality fuel supplier and one that uses a high volume of fuel. The next thing is to find a good quality additive that provides what you want from it. There are a number of fuel additives on the market, but they are not all created equal and not all of them do the same thing.
Here are some of the major things that fuel treatment additives do:
1. Improve mileage and power
2. Clean fuel system components like injectors and engine deposits
3. Provide additional lubrication
4. Remove water
5. Increase cetane rating
6. Stabilize the fuel
Find some of our favorite fuel additives below to keep your diesel running smooth.