A Short Guide to Alternative Fuels

Straight Vegetable Oil, Pure Plant Oil, Biodiesel v/s Petrodiesel

Jan 8, 2008

Vegetable and plant oils can be viable fuel alternatives to petrodiesel. Rudolf Diesel said it 100 years ago and the technology is here today. How much do we really know?

Yes, Diesel was a Man

Before sky-high gas prices and global warming concerns, Rudolph Diesel foresaw vegetable and plant oils being used in his engine as fuel alternatives to petrol-based fuels. Over one hundred years after the first diesel engine, its time to take a deeper look at this option.

There are many reasons why alternatives to gasoline are a good idea. Some are political, some environmental and others economic. Whatever the reason, one must understand what these options can and can’t do with the current technology.

The Engine

The alternative fuels discussed must be used in a diesel engine. Historically, fuel injection systems were initially developed for the diesel engine by Bosche in 1922 while the work of Prosper L'Orange led to a pre-combustion chamber, streamlining a self-igniting diesel engine that was smoother and quieter.

The injection system is what determines the emissions. Basically, the higher the pressure in the injection system, the more efficient the engine will be. If a dual-fuel option is used, mixing oil and gas, it would require multi-needle injectors.

The Fuels

SVO - Straight Vegetable Oil. Either straight (fresh) vegetable oil or used oil that is filtered from particles and water (like from fast-food restaurants).

Biodiesel - A mixture of an alcohol and oil, which the resultant glycerin is removed from.

How are they used?

In order for a diesel engine to run on SVO or PPO the engine must be converted and fit with a mechanism to heat the oil in order to reduce the viscosity so that it is more fluid. Biodiesel, on the other hand, requires more serious modifications to prevent damage, such as changing out the pump seals and fuel lines.

Another option is duel fuel, allowing the driver to switch between liquid and Diesel, as needed. Emulsion injection involves water and fuel always used together, which companies like L'Orange offer.

Economic/Conservation Concerns

Back in 1912, Rudolf Diesel said that "The diesel engine can be fed with vegetable oils and would help considerably in the development of agriculture of the countries which use it." A more recent study done by Dr. Peder Jensen of the European Commission in 2003 reiterates that by noting that it is the agrarian sector (in Europe) that has been trying to push this idea along.

Only little refinement of PPO's is necessary to make it usable for vehicle use - basically cold-pressing and filtering. Not only would this develop agriculture, but it would create jobs, thus boosting economy in low income rural areas. Politically, this could become a battle between big oil and agriculture.

Environmental/Pollution Concerns

One slight drawback with SVO is that it is slightly less fuel efficient than diesel fuel and the electric components necessary to heat the oil results in increased energy use. However, there are companies producing systems that address this issue.

Both SVO and PPO are carbon neutral. In short, that means that the carbon dioxide that they put out when the engine is running is cancelled out by the plants grown to supply it (since they absorb it). Oil spills from SVO and PPO will not negatively effect groundwater.

As for Biodiesel, it falls into the same category as viscous crude oil, which puts groundwater at risk. In addition, biodiesel needs twice as much energy to produce it as PPO.

The fact that there are companies offering conversion kits for alternative fuel solutions and equipment, is an indication that the interest in alternative fuel is increasing. Finally, after 100 years, Rudolph Diesel’s vision is being realized.

References and Additional Information:

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