Vegetable Oil as a Fuel

By

 

Rudolf DieselRudolf Diesel invented the diesel engine in the late 1800's. When he exhibited his engine at the Paris World’s fair, it was with peanut oil as the fuel. He envisioned his engine as being able to run on multiple fuels, including vegetable oil.

"The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in the course of time as important as petroleum and the coal tar products of the present time," - Rudolf Diesel, 1911

We can always hope, but the facts are that if we used all our farmland to grow vegetable oils, we would only be able to replace a small percentage of petroleum diesel fuel.

In the beginning, the diesel engine would run on just about anything with enough BTUs. Over the years, the diesel engine was fine-tuned to run more efficiently on petroleum. Also, the fuel has been changed to improve reliability and reduce emission. All of this "improving" prevents us from dumping vegetable oil directly in the fuel tank of modern diesel engines.

SVO or Straight Vegetable Oil will, in most cases, work fine in diesel engines for a tank or two, but for long-term use, we need to make some changes or reliability suffers. There are three options:

  1. We can chemically alter vegetable oil to give it properties more resembling diesel fuel. (aka make biodiesel)
  2. We can blend our vegetable oil with solvents like gasoline and turpentine to give it properties closer to diesel fuel.
  3. We can modify our diesel engine so that it can operate reliably longer on unmodified vegetable oil.

Making biodiesel requires purchasing and working with dangerous chemicals. Making biodiesel also generates a hazardous waste stream that causes all sorts of problems. There has been a lot of research on making, and using biodiesel, and we know biodiesel can be used indefinitely and still maintain a high degree of reliability.

Blending modifies the fuel without most of the problems of making biodiesel, and you don't need to modify your engine. It is highly experimental, and while some have run over 50K miles with no problems, others have had to replace the entire fuel system after only a few thousand miles. Blending is best done on an older (disposable) vehicle.

Converting your vehicle to run reliably on vegetable oil can be a little bit expensive. Once converted, the cost is less than 50 cents a gallon. That is if we use WVO (used or Waste Vegetable Oil) that we collect from kitchen fryers. New, unused Vegetable oil can cost significantly more.