tscombustion.com was their main gateway.
There are, fortunately, vestigial links around the web but the most readable is this discussion from AutoblogGreen.
AutoblogGreen Q&A with Transonic Combustion: Can supercritical fluids give a 30% mpg boost? - Autoblog
There is still a Wiki up and running and the source notes at the bottom are informative though some are in German ( we have a fluent German speaker on staff simply because much of the good research comes out of Germany).
https://en.wikipedia.org/wiki/Transonic_Combustion
Source 1 is the link to their 2010 SAE paper abstract. They have a 5 page review that allows you to parse more detailed information about the test engine in discussion such as it's 17.5:1 compression ratio.
Transonic Combustion - A Novel Injection-Ignition System for Improved Gasoline Engine Efficiency
They could run the engine over a range of loads without a throttle but as I understand it, there was the need to throttle the engine for emission reasons over other operating regimes. A three way catalytic converter was to be employed. When un-throttled, the engine could run at 50:1 AFR. Un-throttled operation was much like that found in diesel engines.
And here are some claims as posted in an article from an MIT Publication.
https://www.technologyreview.com/s/4...e-passes-test/
I hope this gives you some food for thought.