Diesel is cheaper than gasoline worldwide. Hence, diesel engines are used in ships, trucks, buses and big motor cars. These engines however give rise to higher particulate matter, nitrogen oxide, carbon monoxide and other harmful compounds. All these compounds are polluting the air and environment.
The government of countries in the world enacted rules and regulations to control the quality of exhaust emission of the diesel engines. The requirements of the diesel fuel properties have become more stringent in the wake of these rules and regulations.
The diesel fuel properties can be improved by way of fuel modification. Adding diesel additives is one of the ways to modify the diesel fuel properties.
Diesel additives can reduce black smog or particulate matter. The black smog consists of particles of dust and liquid droplets. It is the result of incomplete combustion of diesel fuel. It is related to diseases such as cancer. It contributes to the global warming via greenhouse effect.
Beside black smog, other harmful by-products of incomplete combustion of the diesel engine are nitrogen oxide, volatile organic compounds and ozone. Nitrogen oxide may cause infection in the respiratory system. Volatile organic compounds are the cause of acid rain. Ozone is not emitted directly from the diesel engine. It is formed by the reaction between the sunlight and the air containing hydrocarbon, volatile organic compounds and nitrogen oxide. There is evidence showing that increased ground level ozone caused significant reduction of agricultural yield.
Diesel additives contain oxygenated compounds. They help to stabilize the diesel fuel and reduces quantity of harmful particulate matter, volatile organic compound and nitrogen oxide which are released into the air in the form of noxious exhaust emission.
In the past, sulfur compounds were added into the diesel fuel to improve its lubricating properties. Because of the stringent regulations in the European Union, the United State of America and some other countries, sulfur was removed from the diesel causing lower lubricity. Lubricity is a measure of the extent of a lubricant reducing the friction. Diesel additives may assist in this respect by improving its lubricity without compromising diesel fuel properties.
Due to incomplete combustion, carbon deposit tends to develop at the intake valve and the wall of the combustion cylinder. The carbon deposit reduces the air and fuel drawn into the combustion cylinder causing inefficient and incomplete combustion. Incomplete combustion gives rise to black smog. The compression ratio of the diesel engine will also drop and hence its power.
Diesel additives break the bond between the carbon deposit and engine parts. Once the carbon deposit is removed, there will be lesser particulate matter emitted and lesser fuel wasted. In fact, the diesel engine may have cleaner burn, generate higher power and need lesser maintenance with the presence of diesel additives.
Water enters the diesel fuel in the form of suspended water during refinery, storage and engine operation stage. It damages the injector tip and impairs combustion. Ice forms from the suspended water easily at low temperature in the winter. It will clog the fuel line. Water consists of oxygen and hydrogen which can react with other compounds in diesel fuel to form sulfuric acid. Sulfuric acid could erode engine parts.
Diesel additives improve diesel fuel quality by breaking down suspended water into smaller particles. As a result, it could be burnt easily and emitted as steam. Water particle less than 4 micron will not be abrasive to the injector tips.
Diesel additives can assist fuel economy in the sense that longer distance could be traveled at a given amount of diesel fuel. This is due to better combustion of diesel.
Due to nano properties of some diesel additives that break down diesel into smaller particles, it can reduce air requirement for the combustion process. As a result the combustion goes more smoothly and produces more energy.
In short, diesel additives may provide better fuel economy, cause the diesel engine emit lesser harmful matters into the air and prevent excessive engine wear and tear.