Supercritical Fuel System: 50-75% Improvement in Engine Fuel Economy

The TSCi gasoline fuel charge enters the cylinder at around 400 °C—compared to about 100 °C for a conventional liquid direct injection fuel charge—at precisely Top Dead Center (TDC, 0° crank angle).
The supercritical charge facilitates short ignition delay and fast combustion, with the energy released focused just on pushing the piston down. The fast combustion minimizes crevice burn and partial combustion near the cylinder walls, and prevents droplet diffusion burn.

The TSCi system supports more efficient engine operation over the full range of conditions—from stoichiometric air-to-fuel ratios at full power to lean 80:1 air-to-fuel ratios at cruise.
The software control is key to facilitating the extremely fast combustion, enabled by advanced microprocessing technology. The TSCi injection system can also be supplemented by advanced thermal management, exhaust gas recovery, electronic valves, and advanced combustion chamber geometries. (The Syracuse team, for example, is using exhaust gas heat to help bring the fuel to SC states.) Through the use of its software, the TSCi system can optimize the use of any combustion chamber geometry or piston bowl shape.

http://www.greencarcongress.com/2009/08/sc-diesel-20090804.html
http://www.greencarcongress.com/2010/03/transonic-20100304.html