How gasoline works


Most of us consider pumping gasoline into our cars to be a routine part of our day, but gasoline is actually a fascinating substance literally millions of years in the making. From a chemical point of view, gasoline is as close to a perfect fuel for internal combustion engines as anyone could imagine.

To understand the properties of gasoline, one must first consider how it got here in the first place. The term ‘fossil fuel’ is not an exaggeration when it comes to oil (and ultimately gasoline). Hundreds of millions of years ago, the earth was covered with all sorts of vegetation and large reptilian creatures called dinosaurs.

Eventually all of these living beings died out and their remains became part of the soil. As the land grew over these deposits of decayed plants and animals, pockets formed under tremendous heat and pressure. All of the organic material slowly changed back to essential elements and compounds, such as hydrogen and carbon.

The Law of Conservation of Energy in physics states that energy cannot be created or destroyed, but it can be concentrated. When all of these plants and animals turned to hydrogen and carbon molecules under pressure, their collective energy was concentrated in the chemical bonding process. Essentially, oil deposits contain ALL of the energy which helped ancient plants grow and little dinosaurs become big dinosaurs.

The chemical bonds in crude (unrefined and raw) oil are incredibly strong, so whenever a catalyst is introduced, such as an open flame, the resulting reaction is very powerful. These deposits of oil are scattered all over the globe, but the largest supplies are found under the deserts of the Middle East, Alaska, South America, and some portions of Africa.
Obviously there are limited supplies of raw oil because the conditions which created it in the first place are no longer present.

Gasoline is a by-product of petroleum. Raw oil is really several different substances held together in an emulsion. Some substances in oil will eventually form the basis for plastics or motor oil or hydraulic fluids, but a specific layer will become gasoline. In order to create gasoline from crude oil, an oil company must ‘refine’ it.

This is a complicated process, but in general refining, oil means separating out the various levels of fluids found in crude oil and only removing the one called gasoline. Imagine putting corn syrup, water, and vegetable oil in a container. Eventually, the heavier corn syrup would fall to the bottom, the water would essentially float in the middle, and the vegetable oil would float above the water and not mix.

Gasoline would be the ‘water’ in a refining operation, so oil workers must siphon off the middle layer and filter it to remove impurities. This is the substance that is put into pipelines or loaded onto tanker trucks for delivery to gas stations. Some companies may add detergents to their gasoline or boost the octane level, but for the most part, gasoline is gasoline wherever you go.

When the inventors of the internal combustion engine realized they needed a fuel which delivered tremendous energy relative to its size, they realized that gasoline was ideal. Various substances are formed in the refining process, and most of them would successfully blow up a lab with a match, but gasoline happened to have a very strong chemical bond called ‘octane’. Octane is very stable without a catalyst present, so gasoline can be stored in tanks without losing much power or spontaneously exploding by itself.

When an ignition source is introduced, however, the octane bonds fly apart with tremendous force. This force is what drives the controlled explosions inside an internal combustion engine. A mixture of air and atomized gasoline is introduced to a small chamber in a car’s engine. A spark plug introduces a small electrical spark, which causes an explosion as the carbon and hydrogen bonds mix with the oxygen in the air.

This explosive power forces a piston down and the engine’s crankshaft is turned slightly. As the piston is pushed back to its original position, the unwanted fumes and residual from the exploding gasoline are pushed out to the exhaust system. Gas and air are once again sprayed into the chamber, the spark plug sets off an electrical charge and the atomized gasoline explodes again.

This process will continue until something causes it to stop. Gasoline contaminated with water may not explode, so the engine may sputter to an unplanned stop. Spark plugs may become too coated with carbon deposits from the spent gasoline to fire sparks. But the most common reason an internal combustion engine stops running is a lack of fuel. Once the gas tank runs out, the fuel injection system has nothing to introduce to the engine and it stops almost immediately.

Any contaminants in the gas itself can also cause the fuel lines to become clogged, cutting off the supply of gasoline to the engine. These contaminants generally tend to sink to the lower levels of stored gasoline, so many auto experts recommend keeping your fuel tank at least one-quarter full at all times. Fuel filters are inexpensive, but consumers often fail to have them changed out regularly.

Gasoline is really only designed to work as fuel for combustion engines. Some people have used gasoline as an insecticide, paint thinner or general cleaning agent, but gasoline creates invisible fumes which will ignite very easily. It should NEVER be used indoors for any purpose, and clothing contaminated with gasoline should be treated outdoors.

Consumers should only used gasoline for its intended purpose and keep it stored in approved containers. If insecticides or paint thinners are required for a job, it makes much better sense to purchase products designed for those purposes. Gasoline possesses the same sort of explosive energy as dynamite, and burns caused by gasoline can easily become third-degree within minutes.

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