With rising debates on the climate change crisis, researchers and scientists are working tirelessly to provide solutions to combat existing pollution levels and introduce methods to reduce pollution in the future as well. However, it is difficult to incorporate these methods as they are not yet cost-effective or efficient enough to run the global economy. Despite being the most polluting fuel, diesel is used in most heavy-duty vehicles such as trucks and ships because it helps provide massive torque in comparison to gasoline or electricity.
In order to understand why diesel engines produce such high amounts of soot and toxic nitrogen oxide emissions, it is important to understand how a diesel engine works. In a gasoline engine, an electric spark ignites the fuel; however, diesel engines do not require this spark. In a diesel engine, injectors spray fuel at pressures as high as 200 megapascals (unit of pressure) and these droplets travel at 600 meters per second to mix with air in the chamber. Almost immediately, a plunging piston squeezes the particles to create high pressure and consequently the heat generated causes the fuel to self-ignite.
One existing method to reduce toxic emissions is to route low combustion gases from the previous cycle back to the air intake. This procedure, called dilution, reduces the production of nitrogen oxides but in return reduces the temperature due to which, not all fuel is consumed and soot is produced instead.
Charles Mueller, a combustion scientist at Sandia National Laboratories, and his team found a way to reduce emissions in diesel engines all while being cost-effective. Using the mechanism of a Bunsen burner, Mueller explained how the burner has slots near the bottom of the tube and how that helps draw in air and mixes more oxygen to the stream making sure the fuel burns completely. With this, he experimented by equipping diesel fuel injectors with tiny Bunsen burner equivalent metal tubes to ensure that fuel and air mixed completely due to which considerably less soot and nitrogen oxides are produced.
Mueller’s technology, the Ducted Fuel Injection (DFI), received funds from the U.S. Department of Energy’s Vehicle Technologies Office and he hopes to use this to further research into ways that DFI can be introduced to consumer and commercial vehicles with little alterations in existing engines.