Argonne Team Receives DOE Award for Groundbreaking Diesel Fuel Spray Research

Recent DOE Award winners, (L-R) Jin Wang, Chris Powell, Yong Yue, and Steve Ciatti, stand in front of their fuel spray injection chamber. Using the synchrotron beam at the APS, the team is able to probe the fuel spray and study the process of combustion.

A team of Argonne scientists (Jin Wang, Steve Ciatti, Chris Powell, and Yong Yue) recently won the 2002 National Laboratory Combustion and Emissions Control R&D Award for groundbreaking work in diesel fuel sprays. For the first time ever, the team used x-rays to penetrate through gasoline and diesel sprays and made detailed measurements of fuel injection systems for diesel engines. This technology uncovered a previously unknown shockwave in diesel sprays, which may eventually help manufacturers improve the combustion process and thus build cleaner, more efficient injection systems.

The team uses x-rays from the Advanced Photon Source (APS) — an Argonne facility dedicated to producing synchrotron x-rays for research — to study the fuel injection system of an engine and to see how combustion works. Studying the breakup of liquid and gas particles near the fuel-injector nozzle will help to advance fuel-injection technology.

"It gives us the ability to track the fuel mass of a spray," says Steve Ciatti. "It's unique. The standard is to use optical-based techniques like lasers or photos, but with those techniques you can only see the external functions."

Laser light near the nozzle causes large numbers of droplets in the high-pressure fuel spray to scatter, limiting the quantitative evaluation of the spray. The highly penetrative nature of the X-ray beam makes them ideal for studying extremely dense droplets composed of materials with a low atomic number. The team can more completely define the structure of the mass of fuel and track where it is at any given time using the x-ray beam.

Steve notes the research they are doing at APS is critical because cleaning up diesel engines is necessary to reduce air pollution from semi-trucks, trains, and potentially diesel-hybrid automobiles. To understand diesel emissions, it is key to understand diesel combustion, which is defined by the fuel spray.

The team also has found the presence of shockwaves in modern injection systems and measured the air/fuel composition in the core of diesel sprays. This observation has never been made before. Jin notes that because they are able to vary the conditions of the spray, they are able to study the structure and the speed of the shockwaves. This research can then be used by fuel injection manufacturers to help design better, more efficient systems. In addition, the technique offers promise for similar studies in dense plasma and other optically dense structures.

The team plans to continue their research, increasing the temperature and pressure surrounding the fuel injector to create a more diesel-like atmosphere. These conditions will allow them to observe fuel injectors and combustion under more realistic conditions.