At Sandia National Laboratories in Livermore, California, Jacqueline Chen and Chun Sang Yoo use supercomputers to simulate burning fuel. The image at right depicts a cold jet of ethylene (a hydrocarbon similar to that found in automotive gasoline) combusting in hot air. By controlling the speed of the ethylene jet, Chen and Yoo alter how rapidly the fuel burns, a measure of its efficiency. (The goal is to optimize the speed. Think of a birthday candle: Blow on it gently and the flame intensifies, but blow too hard and the flame goes out.)

In this model, blue and green represent formaldehyde, a by-product of ethylene ignition. Red represents hydroxyl radicals, markers of flame. The technology can also depict alternative fuels like ethanol and biobutanol, paving the way for greener internal combustion engines in years to come.