Running a Diesel Engine on Vegetable Oil

July 14, 2006— -- I began the project "Grease Not Gas" in the hope that I could run a car on society's waste. I first heard about the possibility of using vegetable oil in cars in 1999. At first, I didn't believe it because it seemed to me that if this was really possible everyone would be doing it. Nonetheless, I was determined to find out if regular old vegetable oil could be used as fuel.

As one may expect restaurant owners are happy to get rid of waste that they usually pay to have taken away. Just don't make a mess or you and other fellow greasers won't be welcome back. My first few trips were hard because I was new to the whole thing. Now after fifteen trips across the country it's become quite simple.

Turns out, diesel engines' simple design allows for virtually anything oil-based to be used as fuel. The inventor of the motor, Rudolph Diesel, used peanut oil in his original design. He said in 1911, "The use of plant oil as fuel may seem insignificant today. But such products can, in time, become just as important as kerosene and these coal-tar-products of today."

To try this theory out I bought an old Chevy pick-up truck. I didn't know much about diesel engines or how they could burn grease for fuel. Over the next seven years, however, I found out.

I have converted several different types of vehicles with diesel engines to be able to run on grease rather than diesel. Thanks to the conversion process I have traveled over 200,000 miles without paying for fuel. In my travels I found that it takes a certain amount of work to make it happen but it's all true, you can run just about any diesel motor on any organic oil.

Once I understood that vegetable oil would burn in the diesel motor it was time to figure out how to make it work. If grease is used for cooking for too long it becomes too solid to be used as fuel. It's important to find clean grease from a restaurant that changes its oil frequently. Asian cuisine is usually the best bet, but you never know what you'll find, it really depends on the habits of the restaurant and its kitchen crew. Once I started to find clean grease I realized it's not gross, it generally doesn't smell bad or have tons of food particles floating in it.

The cleaner the grease the thinner it's going to be, but it's never going to be thin enough to use as fuel. We have to thin the grease down to match the thickness of diesel fuel.

There are two ways to achieve the desired consistency. One is to remove the glycerin through a chemical process, creating biodiesel. Biodiesel is a great renewable resource and it's better for the environment then diesel fuel. It is, however, an aggressive solvent which means it's ultimately damaging to the vehicle. The solution that most people seem happy with is a blend of 80 percent diesel with 20 percent bio. This ratio is known as B20 and considered the least harmful.

The second option is to heat the grease to around 160 F which thins it down as well. This is the process I prefer. Unlike the making of biodiesel there are no toxic chemicals involved and no waste glycerin. I wanted to burn 100 percent grease out on the open road, so I now heat the grease known as Straight Vegetable Oil or SVO.

Burning anything creates greenhouse gases, but the crops grown to make the oil help use up carbon dioxide through photosynthesis. This process is called a closed carbon cycle and it helps reduce the effects of global warming.

I hope that all my trials and errors can help more people create a system that works well and reduces human beings' impact on our planet.