Very often I am asked by my diesel customers about the diesel fuel on the market today,
with its low sulfur content. Over the years with all the restrictions that are being placed on engine manufactures, many changes have had to occur, just like the E15 that I previously wrote about for gasoline engines. I recommend that if you operate a vehicle or truck that uses diesel fuel, I would use a fuel additive at every fill up. Below I have explained a few key things about diesel fuel.
Because of their unique compression-ignition principle, diesel engines run on fuel oil instead of gasoline. The fuel is injected into the cylinder at the end of the compression stroke and the heat of compression ignites the mixture. Diesel fuel used in automotive applications comes in two grades: No. 1 diesel fuel and No. 2 diesel fuel. No. 1 diesel is the more volatile of the two and is designed for engines that will operate under varying load and speed conditions. No. 2 diesel is designed for a relatively uniform speed and high loads.
Cetane number
The cetane number of a diesel fuel refers to the ease with which a diesel fuel ignites. Don’t confuse cetane ratings with octane ratings. Octane ratings refer to the slowing or controlling of the burning of gasoline. Cetane ratings refer only to the ease or speed of the ignition of diesel fuel. High cetane numbers mean that the fuel will ignite with relative ease or that it ignites well at low temperatures.
Viscosity
Viscosity is the ability of a liquid to flow. Water, for instance, has a low viscosity since it flows so easily. The viscosity of diesel fuel is important since it must be low enough that it flows easily through the injection system, while at the same time being high enough to lubricate the moving parts in the injection system. No. 2 diesel fuel has a higher viscosity than No. 1, which means it lubricates better, but does not flow as well.
Because of this and its lower cetane rating, No.
2 diesel is not as satisfactory as No.
1 in extremely cold weather.
One more word on diesel fuels. No matter what you’ve heard elsewhere, don’t thin diesel fuel with gasoline in cold weather. The lighter gasoline, which is more explosive, will cause rough running at the very least, and may cause extensive engine damage if enough is used.