Lean and Clean Combustion for the New Millennium

Internal combustion engines have been identified as the source of one-third of pollution and ozone-depleting greenhouse gases. Computational studies using a new comprehensive combustion model at ORNL, with perspective from our industrial partners GM and Cummins Engine, are meeting the pollution and global warming problems head-on by identifying designs that achieve lean fuel limits, low emissions, and high energy efficiencies. This work has been supported by the DOE's Energy Efficiency and Renewable Energy Office and the Office of Computational and Technology Research.

The sequence of images above shows NOx emissions before, during and after ignition in an engine cylinder. High emissions (.0008 g/cm3 and above) are shown in red; low emissions (.00005 g/cm3 and below) are shown in blue. The sequence corresponds to crank angles -19.99, -4.85, 10.14, and 25.14, respectively. Click on the small images to see larger (approximately 640x480) images.

This visualization shows cylinder temperatures immediately after ignition ranging from 882K (blue) to 2910K (red). Temperature is a critical factor in combustion efficiency, NOx production, and plug life. Click on the image to see a larger (approximately 640x480) image.

Above are single frames from each of several animations recorded in real time from an Onyx Reality Engine workstation at ORNL. Click on the frames to see the MPEG movie from which it was taken. These visualizations were conducted as part of a collaborative visualization development effort between Sandia National Laboratories' Synthetic Environments Lab and Oak Ridge National Laboratory's Center for Computational Sciences Vizualization Lab in fall of 1997. The first three animations show the animated combustion zone with temperature profiles. The last two use NOx profiles. Within the animations, each piston cycle consists of 41 time steps.

Osman Yasar (yasar@ornl.gov or yasar@ams.sunysb.edu)
Ross Toedte (toedte@ccs.ornl.gov)