Why Convert Our Car?
We needed to convert the engine in our car because vegetable oil is more viscous than diesel. So, we needed to heat vegetable oil before it enters the engine. Heating vegetable oil decreases its viscosity. As the temperature increases, the vegetable oil molecules separate from one another, and the vegetable oil flows more readily.
In the fuel tank, which is located in the trunk of our car, the vegetable oil is heated with coils. The vegetable oil is carried from the tank to the engine through a hose that is also heated. This is done by surrounding the hose for the vegetable oil with a larger hose that contains a heating liquid. So the heat from this liquid keeps the oil warm until it reaches the engine.
When the engine is cold, I start the car on diesel. Once everything heats up, I flip a switch, and the hot grease starts flowing. The car runs best when the engine temperature is at least 80 °F.
Before I turn off the engine—especially if it is cold outside—I switch back to diesel to flush the vegetable oil out of the engine. Otherwise, the oil will cool down and harden in the engine. As you can imagine, if vegetable oil thickens in the engine, it would be hard to get the car started again!
Is Our Car Really Green?
We decided to use vegetable oil instead of diesel or gasoline because we wanted a car that was better for the environment. So how “green” is vegetable oil?
One clear advantage is that vegetable oil is “carbon-neutral,” meaning that the amount of carbon dioxide released when the vegetable oil burns is the same as the amount of carbon dioxide taken in by plants to grow. So these two effects—the burning of vegetable oil and the use of carbon dioxide by plants to grow—cancel each other out, resulting in no net increase of carbon dioxide in the atmosphere.
Another advantage of a vegetable car is that it pollutes less. For instance, compared to a traditional car powered by gasoline or diesel, our car produces 50% less carbon monoxide, 50% less hydrocarbons, and no sulfur oxides.
There are other sources of energy derived from plants with similar potential. For instance, scientists are exploring how to use a plant fat produced by algae called triacylglycerol as a fuel.
Scientists are also studying how to produce energy from cellulose, the fibrous or woody material of plants and trees made of carbon, hydrogen, and oxygen atoms. By removing oxygen atoms from cellulose, it would be possible to produce molecules that contain only carbon and hydrogen atoms. These molecules form what is known as “green” gasoline, a substance that packs more energy than cellulose.
Vegetable oil, algae oil, and green gasoline, generically known as biofuels, might change the way cars will run in the future. In the meantime, you can still use cooking oil!