First of all, most AMM use a hotwire to measure mass flow. This essentially is a wire held in the center of the air flow thru which a regulated amount of current is routed to maintain a certain temperature...
So, if a larger flow goes past it, cooling is higher, and more current is required. Considering that the main components of air are O2 (21.7%)and N2 (78%) and a balance of irrelevant noble gases, and considering that the densities as well as heat capacities, and hence convective heat-transfer characteristics of N2 and O2 are similar, the AMM cannot determine how much O2 is being fed to the engine if you would use O2 enrichment as proposed. So this would be problem Uno.......There is no control mechanism which would be able to take into account the amount of O2 being fed. Only downstream of the engine, thru the O2 sensor you could control fuel after the fact...which may not be sufficiently fast....
Problem Duo, however, is the show stopper.....with only very small percentages of O2 enrichment, temperatures are achievable much higher than your engine block can withstand.In fact, only a couple of percent O2 enrichment is required to increase maximum temperatures 100 s degrees.....With these engines, the flame generated is essentially an Turbulent Non-Premixed Flame. These flames, although somewhat tempered by flame stretch, run very close to adiabatic flame temperatures. I.e. very high.
Problem Three, also a show stopper is detonation. With increased oxygen concentrations, radical pools of reactive species essential for combustion (O, OH, and H) are generated much faster. Hence the ignition chemistry accelerates dramatically with the increased O2 concentration and the increased temperatures.........Hence, the onset of detonation occurs at much lower boost pressures.....and if it occurs it is much more violent, capable of destroying engines easily.....
I have a PhD in Aerothermochemnistry...Doing this stuff for a living.....
However, if someone is willing to sacrifice an engine to test where the limits for a Saab are....I would be interested.....


posted by 63.15.185...

• Pure oxygen?, Alex, Wed, 6 Feb 2002 12:33:06
  • I thought about using just compressed air...., Jordan, Thu, 7 Feb 2002 03:18:20
    • What you need is an VNT turbo..., Street, Thu, 7 Feb 2002 15:41:53
      • Re: What you need is an VNT turbo..., Street, Thu, 7 Feb 2002 15:55:05
    • funny you mention it, dave n, Thu, 7 Feb 2002 11:59:42
      • I want flames out the back ;-)., Jordan, Thu, 7 Feb 2002 17:14:57
      • yup...., kooch, Thu, 7 Feb 2002 12:38:21
    • Re: I thought about using just compressed air...., patprice, Thu, 7 Feb 2002 11:24:52
    • Re: I thought about using just compressed air...., Dean, Thu, 7 Feb 2002 10:12:40
  • Re: Pure oxygen?, Johann F, Wed, 6 Feb 2002 19:45:21
    • Re: actually not flame speed, Loo Y., Wed, 6 Feb 2002 20:36:05
  • Re: Here is the load down...very long/scientific, Loo Y., Wed, 6 Feb 2002 17:11:44 <-- Viewing This Message
    • Oh, his name is raul, dave n, Sat, 9 Feb 2002 21:01:38
    • Can I get fries with that?......., SteveW, Wed, 6 Feb 2002 23:08:22
      • Re: Well-done intake Valves...., Loo Y., Thu, 7 Feb 2002 09:58:26
    • Wow! Thanks Loo, good info! I digress. n/m, Alex, Wed, 6 Feb 2002 17:55:55
      • Re: No engine donation in the persuit of knowledge? :-), Loo Y., Wed, 6 Feb 2002 20:24:46
  • Re: Pure oxygen?, peter , Wed, 6 Feb 2002 16:11:41
  • Why nobody does this, saabaru, Wed, 6 Feb 2002 15:22:28
  • If you must try, see this link >, StanleyB, Wed, 6 Feb 2002 15:15:41
  • knock knock no head!, Dean, Wed, 6 Feb 2002 14:22:33
  • NOS seems to be tried and true..., Rookie, Wed, 6 Feb 2002 14:13:34
    • Besides...according to your post below you run 13's..., Rookie, Wed, 6 Feb 2002 14:21:17
      • 13's isn't fast enough!, Alex, Wed, 6 Feb 2002 14:32:04
    • I plan on it. Theoretically discussion only =) n/m, Alex, Wed, 6 Feb 2002 14:16:41
  • No Way......, SteveW, Wed, 6 Feb 2002 12:50:29
    • =(, Alex, Wed, 6 Feb 2002 13:37:55
      • BOOM!!!!!!!!!!!!!!, Street, Wed, 6 Feb 2002 14:07:35
        • Aren't explosions good?, Alex, Wed, 6 Feb 2002 14:24:54
  • wouldn't that burn too hot, Chad B, Wed, 6 Feb 2002 12:34:35

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