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This may be a clever innovation on introducing air and fuel into the combustion chamber.

(tease)
"Georgia Tech researchers have created a new combustor (combustion chamber where fuel is burned to power an engine or gas turbine) designed to burn fuel in a wide range of devices ― with next to no emission of nitrogen oxide (NOx) and carbon monoxide (CO)..."

(URL)
http://www.gatech.edu/news-room/release.php?id=1020

The cartoon show fixed combustion chambers (for heat) rather than pistons etc. (for gas expansion).

DAS

Not quite understanding why reverse-flow would provide all
those benefits, but I do see the point of having air/fuel
mix and combustion products sort of mixin' it up together in
the chamber as "instant EGR". The Prius engine, in fact, does
a similar trick with VVTi timing/overlap and eliminates the need
for any external EGR hardware. The only problem I would guess
at with the gatech system is the need for high-temperature
nozzle components for fuel and air since they're sort of right
there in the primary exhaust stream...
.
_H*

My first impression was that air injection down the walls of the cylinder might help cool them. This may have little basis in fact, though.

DAS

hm interesting discovery but too early in its stage to show us number data.

looks like direct injection as applied to gas turbines/Brayton cycle? It seems as though this would ensure combustion takes place more evenly (statistically speaking) throughout the space, and not concentrated in a smaller volume as occurs with normal fuel/air injection, where most combustion initiates at one spot past the injector, where the mixture has expanded to the proper pressures for ignition.

traditionally the fuel/air ratio is set in the swirl cup prior to injection to the combustor.

It seems like this would be limited to can combustors where the geometry can be controlled. Most larger engines use annular combustors or cans withe free communication between them, making the airflow far more complex.