quote:
Originally posted by Ken2:
Hi Bob,
Just a note to clarify, #1 diesel fuel is not a superior product to #2-D. #1-D is a lower viscosity, lower flash point, has a lower floc point (where the cold causes the wax to crystalize), and also lower BTU content. It's widely used to blend with #2-D for winter use in cold climates.
Premium #2-D is the superior product: "The premium diesel concept is not the same as that of the premium gasoline. Gasoline engines of certain types and compression ratios require a higher octane fuel to avoid knocking. Therefore, premium gasoline is required for these vehicles and is provided by all fuel suppliers. Premium diesel, on the other hand, is related to varying one or more fuel properties. Some of the more-talked-about fuel properties are: cetane number, low temperature operability, stability, lubricity, detergency, and heating value. The suppliers of premium diesel fuel evaluate their marketing area and provide a fuel that has one or more of these improved properties. The level of improvement in each property varies from one supplier to another." (From a Chevron pub.)
There is no widespread agreement on what should consitute a standard for premium #2-D. Consideration is any two of the following-->138,700 btu/gal, >47 cetane, specified low temperature operability, specified 150°C thermal stability, specified fuel injector cleanliness.
Ken
Actually Ken, I had not intended to get into this as of yet, but I do agree with you to some extent. First let's explain something so others can relate what we are talking about.
Fuels with naturally high cetane pack less energy per gal. Cetane is a measure of how quickly fuel ignites. Fuels with more cetane burn faster and starts engines easier. Once you have enough for reliable starts you don't want more.
Most engine manufactures recommends and API gravity of no more than 35 for common fuel. API gravity is a measure of the fuels density(or weight per gal). The higher it goes the less the weight per gal and the less energy it contains. As a general rule, energy content of fuel decreases 3-5% for every 10 degree increase in API gravity. Lower energy content will result in roughly the same percentage decrease in engine power and raise fuel consumption.
Now, my statement in the previous post was not to make a #2 it into a number 1 fuel but actually get the benefits of number 1 while staying in a #2 grade API. So whats the benefits of number 1 D fuel?, easier starts due to easier ignition, less smoke, cleaner injectors. The basic idea of a #1 prem Diesel fuel was set by
if memory serves 2 out of 5 of these parameters are to be considered a prem fuel. So what 2 do you have when you fuel up? As pointed out, there's no consistency thus, the fuel additive.
Here is a list and this doesn't include lubricity as one of them as they didn't have a current test to test the lubricity enhanced fuels. So that isn't included as one of the items they look at in a prem fuel, So when getting a prem #1, you have less lubricity as a norm, so now you're paying more for less.
Now, given that, lubricity is a major factor in diesel fuels. unfortunately as noted above this isn't a requirement when you get to the pump to be demonstrated. This is where a #2 diesel fuel excels as it has higher levels of sulfur which provides better lubricity. The problem here is that Gore was able to have the sulfur content of the fuel reduced for on road use(due to heavy black smoke among reasons given) so when this took place many engines developed seal problems in their pumps. This natural lubricity was being reduced so to reduce emissions. As you know, off road fuel,(with dye) has higher amounts of sulfur. Sulfur is actually a double edge sword, as it helps lubricity, it also leaves a residue, called carbon. As sulfur is burned it becomes a sulfuric acid byproduct and starts leaving deposits and this creates hot spots in the cyl as well it clog's injectors and created uneven burn which also causes reduced fuel economy. A higher api gravity fuel such as #1 has a much lower amount of sulfur and doesn't cause that as much. Well, that's one of the neat benefits of the fuel additive, it neutralizes the sulfur but adds the lubricity back in. All this without increasing the api gravity. Also the additive will increase the cetane with out increasing the api gravity thus, it will burn or ignite easier, but yet have the btu's or energy of the #2 fuel. So, in effect, your getting some of the benefits of the #1 but with the #2, kind of like taking the best of both and blending them together into one.
Thought you might like to see why lubricity is so important in a fuel injection system. Notice all the mechanical moving parts in an injector. This is the same for gas and diesel engines as they all have springs, check balls, pistons, valves, so imagine running that with a low lubricity package in the fuel system. My question to you is this as many are asking how often should I run a fuel treatment, How often do you know that the fuel you're using has a lubricity package that will keep the injectors not only clean but lubricated as well as reduce any water ingestion so that these parts don't get corroded? That imo, is why I run a fuel additive in every tank full. There's no consistent requirement for fuel jobbers to supply you with any of this info.
Ken, I hope that clarifies what I was saying earlier.
bob