Diesel fuel is essentially a hydrocarbon molecule with complex structure. Just like any organic substance, it can be affected by environmental elements. This also applies to natural gas, gasoline and kerosene. Owners of diesel cars should also know how environment could affect diesel fuel. Things that can affect diesel fuel include light, metal, water and temperature. When diesel fuel is exposed to direct sunlight, the oxidation process can be accelerated, because light is a catalyst. Oxidation happens when oxygen reacts with a part of the diesel fuel, causing changes in structure and properties. When diesel fuel is oxidized, polymers are created. Changes happen faster, because polymers react with one another through chain reactions. This causes diesel fuel to break apart, with the heavier components sticking together. This causes them to sink to the bottom of the tank, because they are heavier. Heavily oxidized diesel fuel no longer burns efficiently and this could cause imperfect combustion. It means that deposits will form, because some components don’t combust. Another symptom of heavily oxidized diesel fuel is reduced fuel economy and poor emissions.
Oxidized diesel fuel is also called stratified fuel and during combustion process, its maximum energy value is lower than fresh fuel. It’s a bad thing for owners of trucks and diesel car, if available fuel supply is oxidized. Other than direct sunlight, water could also speed up the oxidation process. Water absorbs various gases, including oxygen and this speeds up the oxidation process. Metal could also cause faster oxidation, however they don’t donate oxygen and only work as catalyst when enough oxygen is available near diesel fuel. A simple experiment is by putting a small amount of diesel fuel in a glass jar and leave it exposed to sunlight. Eventually it will get darker, because one of the signs of oxidation is discoloration.
Another big problem is if diesel fuel is contaminated by specific kind of microbe. Because diesel fuels are consisted of organic molecules, it will be affected by biological processes caused by microbial influences. When specific species of microbe contaminate diesel fuel, it will eventually break down. Due to these issues, diesel fuel needs special care when stored, compared to gasoline. For owners of diesel cars, they may store fuel, including during winter, especially if fuel is difficult to obtain. When we need to store fuel for a long time, it is a good idea to add additives, especially fuel stabilizer. Car owners may need to consider whether it is necessary to store diesel fuel for a long period of time. This is necessary, because improper storage could cause microorganism contamination easier to happen. Fungus and bacteria may affect diesel fuel, the breakdown process could happen faster, especially if water accumulates inside the storage. The storage area should have low humidity level and it may be a good idea to put a dehumidified device. It is important to keep diesel fuel fresh and prevent any harmful reaction. We should know that diesel fuel that’s stored in car’s tank for a long time could eventually break down.