When it comes to powering large vehicles, such as semi trucks and construction machines, standard gasoline just does not do the job. Instead, a higher thermodynamic and more efficient substance is used called diesel fuel, a fluid usually derived from petroleum. Rather than using spark plugs for the combustion of an air and gas mixture, diesel engines’ fuel ignition results simply from compression and the injection of fuel into the inlet air mixture.
Unfortunately, the use of diesel fuel can lead to harmful emissions like many other forms of combustible power. These engines can release harmful NOx gas into the air. However, in order to prevent these hazardous gases, systems are required to pump diesel exhaust fluid (DEF) into the exhaust stream to break down the NOx into harmless emissions of nitrogen and water.
NOx emissions can end up filling the air and even contaminate water. Unfortunately, water is one of the most valuable and, in many regions, also one of the scarcest resources in the world. Global water demand is projected to grow from around 4,500 cubic kilometers in 2010 to about 6,350 cubic kilometers in 2030. But thanks to technologies such as these pumps, over 90% of the world’s population is actually expected to have access to clean drinking water by 2015. Water technology exports alone are worth around $2.7 billion.
To ensure steady injection of DEF, diesel exhaust fluid pumps can push this fluid where it needs to go. The Environmental Protection Agency (EPA) actually requires vehicle manufacturers to ensure these engines cannot run without DEF. They enforce the use of DEF not only due to its breakdown of NOx, but because DEF is also not toxic or harmful. In fact, it is the least hazardous substance used throughout diesel engines.
Diesel exhaust fluid pumps can span anywhere from centrifugal drum pumps to high pressure diaphragm pumps, but must be made from specific materials. While harmless to people, DEF is still corrosive to some metals, such as carbon, steel, aluminum, copper, and zinc. Stainless steel is the ideal material to be used for diesel exhaust fluid pumps. More efficient than other mechanisms such as catalytic converters, these pumps are important to keep diesel engines running properly, without harmful emissions. With the current focus on environmental conservation, Environmental Protection Agency guidelines for diesel use will likely continue to become more strict, meaning pumps will continue to evolve.