Summer 2002 -- vol. 20, no. 2 logos home page Contact the logos editor Argonne home page Feature articles Globus software plugs users into the grid Blood-vessel simulations provide valuable data for doctors Good-neighbor Argonne helps high-tech companies Argonne Update Pres. Bush visits Argonne for homeland security demos Super-slick coating nears commercialization IPNS named 'Nuclear Historic Landmark' X-rays expose secrets of diesel combustion

X-rays expose secrets of diesel combustion

by Katie Williams

Groundbreaking research in the use of X-ray beams to analyze diesel fuel injector sprays may lead to higher efficiency in diesel engines that use fuel injection systems.

The Argonne research team, which includes Jin Wang of the Experimental Facilities Division and Steve Ciatti, Christopher Powell and Yong Yue of the Energy Systems Division, won the U.S. department of Energy's 2002 National Laboratory Combustion and Emissions Control R&D Award.

The team was also named as a finalist in Discover Magazine's 2002 Innovation Awards, and they were most recently highlighted in Science. "This research has been full of excitement since the idea of using 'X-ray vision' to study high-pressure fuel sprays was first conceived three years ago," said Wang, who is the driving force behind the experiment.

AWARD WINNERS – Jin Wang (left), 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 in a diesel-like environment. The goal is to create cleaner, more efficient engines.

"It's nice to be recognized for research that is doing its part in pollution reduction," said Powell. "We're working very hard at it, and it's something no one else has been able to do."

The team uses X-rays from the Advanced Photon Source (APS) – a facility dedicated to producing synchrotron X-ray beams for research – to study the fuel injection system of an engine and to see how combustion works.

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

The team can more completely define the structure of the mass of fuel and track where it is at any given time using the APS.

Ciatti said the research is critical because cleaning up diesel engines is necessary to reduce air pollution from semi-trucks, trains and diesel-hybrid automobiles. To understand diesel emissions, it is necessary to understand diesel combustion, which is directly affected by the composition of the fuel sprays.

Other information the team has found includes the presence of shock waves in modern injection systems and air/fuel vapor in the core of diesel spray.

The research is still in the early stages of development, but Powell said the team plans to increase the temperature and pressure surrounding the fuel injector to create a more diesel-like atmosphere. They will be able to observe fuel injectors and combustion under more realistic conditions.

The X-ray technique may be used in the future for similar studies of dense plasma and other optically dense structures.

"This technique we have developed here is not only for fuel spray," Wang said. "It can be used for other highly transient phenomena like looking at plasma discharge or spray coating. Most of these materials are optically opaque. The X-ray makes them a perfect candidate for this type of application."

For more information, please contact Catherine Foster (630/252-5580 or cfoster@anl.gov) at Argonne.