Transonic Combustion - SAE Paper
Since the prior thread is closed, I'm posting this in a new thread referencing the original thread. I previously posted that when new technical information became publicly available, I would link it here.
On October 25, 2010, Transonic Combustion presented an SAE technical paper detailing it's novel new injection ignition combustion process at the Society of Automotive Engineers 2010 Powertrain Fuels and Lubricants Meeting in San Diego CA.
"Spark ignition gasoline engine efficiency is limited by a number of
factors; these include the pumping losses that result from throttling
for load control, spark ignition and the slow burn rates that result in
poor combustion phasing and a compression ratio limited by detonation of
fuel. A new combustion process has been developed based on the patented
concept of injection-ignition known as Transonic Combustion or TSCi?;
this combustion process is based on the direct injection of fuel into
the cylinder as a supercritical fluid. Supercritical fuel achieves rapid
mixing with the contents of the cylinder and after a short delay period
spontaneous ignition occurs at multiple locations. Multiple ignition
sites and rapid combustion combine to result in high rates of heat
release and high cycle efficiency. The injection-ignition process is
independent from the overall air/fuel ratio contained in the cylinder
and thus allows the engine to operate un-throttled. Additionally, the
stratified nature of the charge under part load conditions reduces heat
loss to the surrounding surfaces, resulting in further efficiency
improvements. The short combustion delay angles allow for the injection
timing to be such that the ignition and combustion events take place
after TDC. This late injection timing results in a fundamental advantage
in that all work resulting from heat release produces positive work on
the piston. Other advantages are the elimination of droplet burning and
increased combustion stability that results from multiple ignition
sources."
How long does it take from when I stick the key in until there is sufficient supercritical fluid available to start the engine?
Since startup heating is entirely electrical, it takes a few seconds to get enough heat buildup. It's on par with Diesel glow plugs. Once the engine is running, recovered waste heat takes over a large portion of the fuel heating.
You are partially correct. TSCi(tm) utilizes compression ignition, but the injection techniques, the cylinder geometries, and the characterisitics of supercritical gasoline are different enough that it's called Injection Ignition, instead of Compression Ignition. It's definitely a close relative. It's easier to say what it isn't. It's not quite Diesel, and not quite HCCI, but with similarities to both.
The whole point is that our technology allows for better than Diesel engine efficiency, while burning gasoline. The better than Diesel efficiency comes primarily from additional waste heat recovery from the exhaust, used to pre-heat the fuel, and from the mixing/burn characterisitcs of supercritical gasoline.
We cannot switch the whole world over to Diesel fuel. When barrels of oil are refined, you get a mixture of Diesel fuel and gasoline, in the middle distillate range. U.S. refineries are optimized for an approx. 60% gasoline/40% Diesel ratio. Europe's refineries are approx. 50-50. If you built all new refineries, you could make about 60% Diesel/40% gasoline, but since refineries cost in the billions of dollars, that is not a casual investment. You have to have a more efficient solution for all that gasoline.
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