A recent survey of over 200 automotive executives named fuel efficiency as the top concern for the modern automotive (light-duty) consumer – 92% of respondents ranked this higher than safety, comfort, vehicle styling, or environmental friendliness.  And for the big truck (heavy-duty) consumer, the National Petroleum Council identified the diesel engine as the powertrain of choice because of its combination of power and efficiency.  In addition to the demand for high-efficiency vehicles, fuel economy and emissions standards for all on-road vehicles place further constraints on vehicle and powertrain design.  To improve efficiency and emissions performance, diesel engine design concepts for both light-duty and heavy-duty vehicles utilize features like novel waste-heat recovery, increasingly effective exhaust aftertreatment, and advanced combustion.  One advanced combustion concept – injection schedule design – is a way to reduce emissions using in-cylinder techniques that could reduce the burden, size, and cost of aftertreatment systems while meeting the high-efficiency demands of consumers.  Data from the heavy-duty diesel optical engine facility at Sandia National Laboratories will illustrate the use of post injections, short injections following the main fuel injection, as a way to reduce pollutant emissions while maintaining efficiency.  Examples from conventional diesel operation will show that post injections can reduce engine-out soot emissions by up to 50%, and data from low-temperature combustion (LTC) conditions will show how post injections can reduce unburned hydrocarbon emissions by up to 40% at low-load conditions.  Optical data from this engine, simultaneous laser-induced OH fluorescence and soot incandescence at conventional conditions and simultaneous OH and formaldehyde fluorescence at LTC conditions, help to uncover the mechanism by which these small, close-coupled post injections can have such significant effects on engine-out emissions.  Discussion of future work for injection schedule solutions will provide one pathway to a cleaner, more efficient post-modern diesel engine.

Speaker BIO: Jacqueline O’Connor is a post-doctoral researcher at Sandia National Laboratories in Livermore, California in the Engine Combustion Department within the Combustion Research Facility. Her research at Sandia focuses on using laser diagnostic techniques to understand fluid-chemical interactions in heavy-duty diesel engines for the mitigation of pollutants such as soot and unburned hydrocarbons.  Dr. O’Connor will begin as an Assistant Professor in Mechanical and Nuclear Engineering at Penn State in August 2013.  She received a Bachelors of Science from the Massachusetts Institute of Technology in Aeronautics in 2006, and a Masters of Science and Ph.D. in Aerospace Engineering from the Georgia Institute of Technology in 2009 and 2012. Her dissertation described the velocity-coupled response of swirl-stabilized flames to transverse acoustic modes for gas turbine applications.  Jacqueline was a National Science Foundation Graduate Fellow from 2006 – 2009 and has received awards from the AIAA, ASME, and Georgia Tech, among others. She is an actively involved member of the ASME, SAE, and AIAA. Her research interests are in combustion and fuels, hydrodynamic instability, acoustics, and high-speed diagnostics.