A guy walks into a bar and says……

"Does anyone know about Diesel Fuels?"

Diesel fuel is more efficient than gasoline because it contains 10% more energy per gallon than gasoline. But there are a few kinds of diesel fuel: Just as gasoline is rated by its octane, diesel fuel is rated by its cetane, which indicates how easy it is to ignite and how fast it burns. Diesel fuel is safer than gasoline because its vapors don’t explode or ignite as easily as gasoline vapors.

When exhaust from conventional diesel fuel was found to cause cancer, clean diesel engines were developed. Although conventional diesel fuel-burning vehicles are still on the road, states and the federal government enacted legislation that will eventually eliminate these older diesels engines.

Standard diesel fuel comes in two grades: Diesel #1 (or 1-D) and Diesel #2 (or 2-D). The higher the cetane number, the more volatile the fuel. Most diesel vehicles use fuel with a rating of 40 to 55.

You don’t have to worry about which type to use because all diesel OEMs specify Diesel #2 for normal driving conditions. Over the road truckers use Diesel #2 to carry heavy loads for long distances at sustained speeds because it’s less volatile than Diesel #1 and provides greater fuel economy.

Diesel fuel also is measured by its viscosity. Like other motor oils, diesel fuel gets thicker and cloudier at lower temperatures. Under extreme conditions it can become a gel, which limits flow. Diesel #1 flows more easily than Diesel #2, so it’s more efficient at lower temperatures. The two types of oil can be blended, and most service stations offer diesel fuel blended for local weather conditions.

If you plan to drive in very cold weather, choose diesel fuel rated at least 10 degrees lower than the coldest temperatures you expect to encounter. Consult your owner’s manual or engine builder for more specifics.

"Red" Diesel Fuel is exactly the same fluid as No. 2 fuel that's used in diesel pick-ups, heavy- duty trucks, buses and some cars on the road. The big difference is red fuel is used for engines that power off-road vehicles, as well as machines like tractors and bulldozers that are used on farms and construction sites.

Because of its price, which typically is much lower than the cost for No. 2 fuel, red diesel is subject to a rebated tax. Although red diesel certainly will "work" in our daily diesel vehicles, using it on the street is not allowed. You could face high fines and penalties for tax evasion if you are caught using red diesel on public roads.

Another type is Biodiesel. This diesel fuel is derived from agricultural materials and has the potential to provide a clean-burning alternative to petroleum.

Rudolph Diesel’s first engine was designed to run on peanut oil. Henry Ford envisioned plant-based fuel as the primary fuel for transportation, so he partnered with Standard Oil to develop biofuel production and distribution.

However, currently the only type of biodiesel fuel that can be used in vehicles in the United States and Canada without violating manufacturer’s warranties is B5, a blend of 5 percent biodiesel and 95 percent regular diesel. Most diesel engines run just fine on blends of up to 30 percent biodiesel.

The bartender looks up and says, "Is this supposed to be some kind of joke?"