Several years ago, diesel engine fuel consumption dramatically improved. Due to recent increases in the cost of gas, it has become very lucrative to use diesel-powered vehicles. Although the cost-per-gallon is about the same as regular gas, the miles-per-gallon benefit derived from these vehicles is very appealing.
As a result, the use of diesel engines in various vehicles is rapidly increasing due to the above-referenced benefits. Although the use of diesel oil does allow for less fuel consumption as well as lower carbon dioxide emissions than previously, it still poses certain environmental problems due to the creation of toxic air pollutants that are detrimental to the general public’s health as well as to diesel engines.
Much research has been done and it was determined that the four most destructive pollutants that cause premature engine failure are: water, glycol, soot and fuel thinning.
- Water – The main cause of the absorption of water into diesel engine oil is due to the small amount of monoglycerides and diglycerides that remain during incomplete combustion. The presence of these molecules acts as a chemical agent capable of reducing the tension of fuel, thus allowing water to combine with diesel engine oils. The existence of water molecules may result in various mechanical problems, which include: corrosion to vital fuel system components; premature failure of fuel pumps; a speed-up of the gelling of residual fuel; and being the cause of pitting on the pistons.
- Ethylene Glycol – Glycol is introduced into diesel engine oils in many ways, including: a broken head gasket; defective seals; thermally-warped cylinder heads; corrosion damage; cylinder wall cavitations; and electrochemical erosion. Several laboratory studies have been conducted and a small amount of glycol was found in the samples. The presence of glycol in these engines is degenerative itself by means of pinhole perforations leading to hydraulic lock; bearing damage due to rust on iron surfaces; and filter blockage.
- Soot – One of the toxic particulate matters that contribute to the emission problem is the presence of soot, created as the result of a process known as ‘pyrolysis.’ This involves the decomposition of organic matters at higher temperatures when oxygen is not present. The result is a product known as char that primarily consists of carbon. Soot occurs because the chemical composition of diesel oil, that includes saturated hydrocarbons and aromatic hydrocarbons, undergoes this pyrolysis which breaks it down into several chemical elements including soot.
- Fuel Thinning – In various laboratory studies, fuel dilution was detected through viscosity and gas chromatography. The primary cause could be incomplete combustion; seal and gasket problems; over-fueling; and frequent short trip driving. It is believed that this dilution is capable of causing damage to the vehicle’s engine. The allowable dilution limit is up to 2%; anything beyond that is considered abnormal and anything above that amount can cause mechanical damage and possible engine failure.
Even though various chemical particulates have been scientifically discovered in diesel fuels, these engines are still considered to be cost-effective with lower fuel consumption, which is a big economic advantage. Manufacturers are constantly finding new ways to help eliminate this problem. With improved vehicle technology, drivers can save more money on gas expenses, protect the environment in general and public health as a whole. Don’t let these diesel engine pollutants rob a diesel engine of its benefits!