FLUID MECHANICS OF DIESEL INJECTION STUDIED AT PENN STATE

Special photography method helps student researchers get a better look at spray patterns.

EXHAUST EMISSIONS FROM DIESEL ENGINES contain numerous pollutants including particulate matter (PM), nitrogen oxides (NO_x), and unburned hydrocarbons (UHC), which are known to cause adverse health effects such as asthma and lung disease. The released quantities of these pollutants are limited by emission regulations in the U.S. and Europe. Research on in-cylinder emissions-reduction techniques, such as advanced injection timings, will help the engineering community develop an understanding of diesel combustion from a fundamental standpoint, allowing optimal injection schedules to be determined more effectively.

Graduate and undergraduate researchers at Pennsylvania State University have been investigating multiple consecutive fuel injections using a simplified experimental setup that allows them to study the fundamental fluid mechanics of multiple injections using high-speed diagnostic techniques. In the preliminary study discussed in the SAE International technical paper titled “The Effects of Injection Timing and Duration on Jet Penetration and Mixing in Multiple Injection Schedules,” the authors utilized schlieren photography to determine the jet-tip penetration and dispersion of helium gas jets, which when scaled properly can mimic some critical behaviors of diesel injection.