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Caution using Biodiesel

Biodiesel is being treated with caution by the fuel injection equipment manufacturers and engine companies.  While many support the development of alternative (non-petroleum) fuels in diesel engines, they are worried about unregulated biodiesel being used in equipment that was designed to run primarily on highly regulated #2 Diesel.

A variety of source materials are used to make biodiesel, which means there are lots of undesirable finished products that could end up in your fuel tank. This is of great concern to diesel engine companies because there can be all sorts of bad stuff roaming through their equipment such as:

• Free methanol
• water
• free glycerin
• Mono-, di-, and triglycerides
• Free fatty acids
• Solid particles and Oxidated fuel.

If your diesel engine / generator is under warranty and you want to run biodiesel, you’d better think twice before filling up your tank.

Biodiesel Pros and Cons

In addition to petroleum, Diesel fuel can be made from various vegetable oils, including canola and soybean. The ASTM has also released a standard, D-6751, for biodiesel fuels. Stanadyne, as well as the other major fuel injection equipment manufacturers, has determined that a blend of 5 percent biodiesel that meets the ASTM D-6751 standard and 95 percent mineral diesel that meets the ASTM D-975 standard should not harm fuel system components. This blend is referred to as B5. As with ULSD, biodiesel fuel also has various advantages and disadvantages:

Advantages of biodiesel

• Reduced exhaust emissions
• Made from a renewable resource
• Almost no sulfur (in the biodiesel itself)
• Higher cetane value (51 minimum versus 40 minimum for mineral diesel)
• Excellent lubricity

Disadvantages of biodiesel

• *Could harm certain elastomers (seals)
• Has poor resistance to oxidation, especially when blended with ULSD. This results in spoilage and the formation of acids and varnishes
• Biodiesel can absorb much more water than mineral diesel
• Has lower energy content

Most diesel engine companies including Aurora Generators will not warranty your engine if anything but normal automotive diesel fuel is use. Many companies simply don’t cover fuel injectors and fuel pumps thus avoiding any disputes on what type of fuels where used and examining the engine for evidence.

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Types Of Diesel Fuel

Diesel fuel is derived from crude oil. It is a mixture of hydrogen and carbon molecules. It is developed for engines that provide energy for power, flow readily in cold temperature, provide low emission, provide good fuel economy, and allow easy start-up. Power generators are run by diesel fuel. The fuel also runs diesel-powered vehicles, such as ships, buses, or trucks. Diesel engines of these types of vehicles are internal combustion engines.

Diesel is used in a high-compression engine. Air is compressed until it is heated above the autoignition temperature of diesel. Then the fuel is injected as a high pressure spray. There is no ignition source. As a result, diesel is required to have a high flash point and a low autoignition temperature. The flash-point of a fuel is the lowest temperature at which it can form an ignitable mix with air. The high flash point in diesel fuel means that it does not burn as easily as gasoline, which is a safety factor. Too low of a flash point is a fire hazard because ignition may continue and lead to explosion.

Autoignition temperature is the temperature at which a substance can be brought to flames without any sort of external force, such as a flame or spark. There are three different types of diesel fuel. These are Diesel No. 1, Diesel No. 2, and Diesel No. 4. The ignition temperature of Diesel fuel No.1 ranges from 450 to 602 Kelvin, Diesel fuel No. 2 ranges from 527 to 558 Kelvin, and Diesel fuel No .4 is 536 Kelvin.

Diesel is a petroleum-based fuel with a high energy content – helping diesel go further per gallon than most other

Refiners reduced the sulfur content in diesel fuel by 97 percent. This new, ultra-clean fuel is important because sulfur tends to hamper exhaust-control devices in diesel engines, like lead once impeded the catalytic converters on gasoline cars. Just as taking the lead out of gasoline in the 1970s enabled a new generation of emissions control technologies that have made gasoline vehicles over 95 percent cleaner, so will removing the sulfur from diesel help usher in a new generation of clean diesel technology.

Physio-chemical properties of diesel fuel

Autoignition Temperature (°C)

• Diesel Fuel # 1 177-329
• Diesel Fuel # 2 254-285
• Diesel Fuel # 4 263