New "Ducted Fuel Injection" May Eliminate Diesel Soot.
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Ducted fuel injection, developed by Chuck Mueller at Sandia's Combustion Research Facility, is able to fine-tune the amount of diesel used in an engine to the point of eliminating between 50 and 100% of the soot... [H]e and his team, Christopher Nilsen, Drummond Biles and Nathan Harry, began experiments that have now resulted in an assembly of four to six small tubes, or ducts, directing fuel mixture from the injector right to the points of ignition. Chuck said that injectors in a traditional diesel engine create local mixtures containing 3-10 times more fuel than is needed for complete combustion. "When you have that much excess fuel at high temperature, you tend to produce a lot of soot," he said...
"Soot is second only to carbon dioxide in climate change, and it's toxic, so its emissions should be minimized," Chuck said. "In the past, there's always been this problem called the soot/nitrogen oxides trade-off. That is: when you do something to lower soot, emissions of nitrogen oxides -- or NOx -- go up, and vice versa... Now that we've got soot out of the way, there's no more soot/NOx trade-off," he said. "So we can add dilution -- taking some of the engine exhaust and routing it back to the intake -- to get rid of NOx without soot emissions becoming a problem. It's like a two-for-one deal on reducing pollutants... This gives us a path to much lower emissions for diesel engines, solving a long-standing problem for this highly efficient technology," he said.
They don't mention fuel savings, but if traditional injection is using "3-10 times more fuel than needed", I would expect miles per gallon to increase as the soot decreases.
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