Sunday, October 19, 2008

Rotating Non-Equilibrium Gliding Arc Plasma Disc for Enhancement in Ignition and Combustion of Hydrocarbon Fuels

No, I am not author of the above title, I just realized the importance of the document for diesel cars!

still searching for the link where it came from!

I have good news for you. The above mentioned document can be used as a cetane number improver for diesel engines, by making a lot of radicals in the suction air! I have yet to try it, but in theory it is worth a try! If nothing else, it takes much less power than a H2 generator and has much higher efficiency!

I will repeat the abstract here:
The best plasma discharge system for combustion applications should generate non-equilibrium plasma with high concentration of active species and intermediate temperatures, high enough to support chain in propagation reaction. The non-equilibrium Gliding Arc (GA) aptly suits this application. A novel, nonequilibrium gliding arc plasma disc reactor has been developed to study possibility of flame speed increase, flammability limit extension for hydrocarbon fuel and oxidizer mixture.
What does it mean? To simplify that paper: you remember why nailing occurs? It is because fuel is dispersed in prechamber but fails to combust. The same happens if you increase the injection pressure past 140BAR, the fuel is sprayed nice and lovely, but the droplet is too small and too fast to keep a burning flame behind it and the flamelet goes out, only to result in detonation of the vapour later. (that is the flammability limit mentioned above!) Air full of nitrogen oxides and intermediate products is very reactive and the paper shows some good increase of resistance of diffuse flame to go out with increasing wind speed.

So intended use?
You install it in suction, even before the air filter. Power it up, run the engine. Now Injection pressure can be adjusted to the point where the injector will have a tendency to make knocking sound. If 20% better combustion speed is achieved, the injection pressure where this happens may be higher some 6-9%, I reasonably expect it to raise from 135-140BAR to 145-150BAR. Not that it is a big improvement, but every improvement of the combustion profile is improvement of engine efficiency!

Next, if this is proved, or maybe not, we can adjust IP timing, perharps retarding it one or two degrees. (moving closer to the top dead center).

One note: oil life might be negatively affected if you put it into much contact with the reactive air. Not by much, only few percent - because it is already in contact with combustion gases, but I thought you might want to know.