An award-winning University of Wisconsin-Madison student hybrid vehicle will become a showcase for advanced fuel technology that harnesses the advantages of both diesel and gasoline. The team vehicles will emit 75 percent fewer greenhouse gases. RCCI engines can achieve efficiencies of between 20 and 35 percent better than with standard diesel engines, which are themselves about 20 to 30 percent more efficient than gasoline engines.
Mechanical engineering professor Rolf Reitz is perfecting a new mixed-fuel technology that harnesses the advantages of both diesel and gasoline.
The process, called reactivity-controlled compression ignition (RCCI), involves two separate fuel injections: First, gasoline is swept into the engine with fresh air, with which it mixes uniformly. Then, a diesel fuel is injected, dispersed finely enough that it ignites under compression.
Mixing the two fuels allows combustion to take place at lower temperatures, which both reduces how much energy is lost in just keeping the engine hot, and minimizes the production of nitric oxides, one of the biggest culprits in vehicle-related air pollution.
The technology also reduces greenhouse gas emissions. Because the process involves pulling in fresh air, more so than standard combustion, leftover carbon is more likely to react with oxygen to form carbon dioxide, rather than being expelled as soot.