Larry Morgan Jr. wrote:Off topic a bit, but crazy things have happened when things get near absolute zero. We have 5 known states of matter now because of it. The one near absolute zero being the Bose-Einstein Condensate. In a few experiments with thing in the nanokelvin range, atoms have imploded together and "disappeared"
And nobody knows for sure what happens at exactly absolute zero... If you use modern equations and quantum theory, since matter is made of energy, you lose all energy. So, the matter ceases to exist, which goes against the law of conservation of energy...
and if matter is utterly destroyed,you should have some serious residual energy (heat) there...think of anti-matter + matter = Huge bang. It basically cracks physics open...
-Bjørn
"Impossible? Nah...just needs more development time"
If you create a matter/anti-matter explosion,and the chamber can hold it, wouldn't you compress atoms to the point of infinite density, which in turn means infinite gravity(ie a black hole)? Assuming that the chamber can still handle the forces, just think of the chamber filling thats going to happen when the intake valve opens! Now thats a pressure drop! ( sorry guys, I couldn't help throwing that one out there.)
as far as optimum fuel/ air ratio, have you ever considered using CO feedback? My understanding is it's way better than excess O2. If you could tune for 200 to 300ppm it would be about perfect.
I think the sensor technology is not available and that may be why you see Excess O2 used as a closed loop feedback.
automotive breath wrote:It's not only about fuel atomization, although that can be big part. Check out this CFD showing flow vectors and equivalence ratios to highlight in cylinder mixing of the fresh charge with residual gas.
"...this means that generally in the cylinder there will be fuel richer regions with lower temperature and leaner regions with higher temperature...."
"...the effect of mixing in the cylinder is very important since it controls the local temperature and composition in the cylinder. There is a correlation between local equivalence ratio and residual gas fraction with temperature. The assumption of homogeneous composition (in the cylinder) could be quite inaccurate even under premixed conditions in the intake port..."
2dumb2kwit wrote:If you create a matter/anti-matter explosion,and the chamber can hold it, wouldn't you compress atoms to the point of infinite density, which in turn means infinite gravity(ie a black hole)? Assuming that the chamber can still handle the forces, just think of the chamber filling thats going to happen when the intake valve opens! Now thats a pressure drop! ( sorry guys, I couldn't help throwing that one out there.)
You'd need a hefty bench to flowtest that one...
And,the seated pressure of the valvesprings
-Bjørn
"Impossible? Nah...just needs more development time"
automotive breath wrote:"...this means that generally in the cylinder there will be fuel richer regions with lower temperature and leaner regions with higher temperature...."
This may be off topic but I would have thought that the highest temperature produced would be for a fuel air mix which was at Stoichiometric ratios about 14.7 to 1. Any mixture above or below this would produce less heat. At ratios greater than 14.7 to 1 the mixture would burn slower and for longer transferring more heat into the piston and cylinder head making the temperature appear higher. At ratios below 14.7 to 1 the mixture would also burn slower but since there is more fuel to vaporize this would reduce the overall heat produced.
The interesting thing here is why does a ratio of around 12 to 1 produce the most power?
tommurphy73 wrote:This may be off topic but I would have thought that the highest temperature produced would be for a fuel air mix which was at Stoichiometric ratios about 14.7 to 1. Any mixture above or below this would produce less heat. At ratios greater than 14.7 to 1 the mixture would burn slower and for longer transferring more heat into the piston and cylinder head making the temperature appear higher. At ratios below 14.7 to 1 the mixture would also burn slower but since there is more fuel to vaporize this would reduce the overall heat produced.
The interesting thing here is why does a ratio of around 12 to 1 produce
the most power?
Regards
Tom
Slower burn could be a complete burn at a given time. No detonation!
The interesting thing here is why does a ratio of around 12 to 1 produce the most power?
The ratio of 12 to 1 created the best power because of the molecular proximity (density of hydrocarbon atoms) which made things easier for the ignition to comence under mixture and pressure.
Now days with the higher energy and multilple spark it might not be the norm it used to be especially in the more thermally efficent power plants.
14.7:1 does not produce the most heat, a slightly leaner a/f ratio produces the most heat.
A slower burning combustion process doesn't necessarily put more heat into the piston / chamber - although it might, but it is likely to heat the engine more, even causing overheating as a result of the continued burning on it's way out the exhaust port.
When I worked on emissions calibration many years ago, we found that oxides of nitrogen, which are formed during high temperature combustion, peaked at ~ 15.5 to 16:1 AFR...
racing97 wrote:The ratio of 12 to 1 created the best power because of the molecular proximity (density of hydrocarbon atoms) which made things easier for the ignition to comence under mixture and pressure.
Now days with the higher energy and multilple spark it might not be the norm it used to be especially in the more thermally efficent power plants.
regards
"Molecular proximity"! This is a key! I've been very busy and haven't had the chance to really delve into this much for a while.
Molecular proximity is a critical component in increasing the effectiveness of a "nitrogen heater / exciter," more widely known as an internal combustion engine.
Flame temperature will vary with engine design and running conditions among other variables. The transfer of this heat to the engine depends on component material of construction and time.
How does air fuel ratio, and burn temperature relate to burn speed? Does the 12:1 ratio burn faster than the 16:1 ratio even though the burn temperature are much the same. Combustion chamber design etc being kept the same.
