the apparent magic of detonation

[JanGeo]

If you have a chance to visit the materials labs of a good college they usually have an octane tester which is a piston that tests the combustion of by compressing it UNTIL IT IGNITES. And how do you think diesel engines operate?? They can start without glow plugs if the engine temperature is above 60-70 degrees easily.

I'm not saying that other things are not happening in this process that Tesla writes about.

[CoyoteX]

Assuming a correct fuel ratio the higher the pressure the faster the flame front travels. So to make this simple lets say that you have a sealed cylinder with gas/air uniformly mixed and you ignite it. The point of ignition starts burning and expanding due to heat and combustion, increasing pressure. This increase in pressure makes the flame front travel faster. This increases exponentially, I am not going to bother with the equations because they are hard to solve in text format. Usually the result is the sealed container will explode once it gets to the point it can't contain the pressure anymore and ruptures. The flame front will not travel evenly because the pressure is increasing up to the point the container ruptures. This is how a pipe bomb explodes so violently, when you could just ignite the same amount of powder in the open and it will just make lots of smoke.

Now put this into a moving piston. The pre ignition happens sometime before the spark plug fires, or the plug fires early. The piston is going upward still increasing the pressure. The flame starts and as it burns it is also increasing pressure. Since it happened early the pressure gets very high and the fuel burns almost instantly Since remember the flame front speed exponentially increases with pressure. The increasing pressure from the piston moving upward and the already started combustion means the fuel is totally burned before the piston reaches top dead center. The engine has enough rotating mass to force the piston up to TDC anyway. From basic chemistry you know that increasing the pressure of a sealed container increases it's temperature so now instead of the normal combustion temperature and pressure you greatly increase the pressure because you are compressing the entire burned air/fuel mix at TDC which increases temperature as much as 5-10x normal. So if you don't break a piston or lift the heads from the excessive pressure which will cause an instant failure of the engine you will over time melt stuff starting with the metals with the lowest melting point showing damage first. It also causes metal fatigue from the stress that over time can cause stuff to break.

You don't get that kind of temperature with normal combustion because as the fuel burns the piston is moving downward increasing the volume of the chamber which also means the temperatures and pressures are more controlled and you don't get a runaway flame front speed. Nice and simple even though I simplified things a bit and left out all the math it should still be fairly easy to follow the logic.


But then what do I know I only have degrees in physics and chemistry.

[CoyoteX]

What everyone is talking about what initially causes pre ignition is typically something like a lot of carbon buildup on the combustion chamber. This carbon can hold a lot of heat so as the piston is going up compressing the air/fuel the pressure is increasing and the temperature. This carbon is already hot so once the fuel gets hot enough that the activation energy required is less than the amount of energy in the carbon deposit the fuel will ignite. This is can be anywhere like 20-40 degrees or so to early and causes what I said in the last post.

Another thing is if the octane is low/compression ratio too high. The temperature and pressure of the piston working normally will either exceed the activation energy and the fuel will ignite early or the normal ignition timing will spark and ignite the mixture. The lower the octane the faster the flame front can travel so the fuel burns faster than the engine expects, This increases pressure rapidly as the engine is still before TDC with the piston moving upwards and you get the same runaway combustion as already described. The engine might be tuned for 93 octane so it expects the fuel to burn at a certain rate, increasing the burn rate by using 87 octane means the engine will have to be retuned. Typically you shape the combustion chamber with a certain flame front speed in mind so if you retard the ignition because of bad gas or whatever reason you do not get efficent combustion. Same thing with running 93 in a car tuned for 87 the fuel burns slower than expected so you don't get the full energy from it. Not considering newer cars that can adjust their timing to suit the current conditions. Even the new cars can not advance the ignition past the table in their memory so if they are not tuned for 93 they won't need it unless the car has problems.

[molecule]

alot of what you said is fine
alot of what you said is false

the difference between high octane fuels is that they are further reduced in their complexity of structure...
basically 87 octane has roughly 3 stages of burn...because fossil fuel is composed of many different densities...it generally contains a few even after refinery in the towers...
spark can only ignite part of the fuel...the flame front propogation is required to burn the rest
higher octane fuels are refined yet even more so that they actually burn quicker...they have less total difference in deviance of their structure and density...and the spark energy can induce a higher percentage of the total burn...
as mentioned earlier...additives are added to higher octane fuels to ward off detonation...to total burn cycle is kept fairly constant in that the fuel now requires less burn time as it is more refined...
however higher octane fuels contain less energy per unit...
lower octane fuels simply have more in them...a part of which burns hotter...
performance motors can produce more hp on high octane because:
they are less likely to detonate and can handle more timing
they are more stable at higher rpms as they burn quicker
being able to rev your motor to 9500 instead of 7200...
well...you lose a percentage of power per cycle on the high octane...
but you gain the repetition....and more power is produced in the same amount of time at higher rpms...

if you downloaded that text...it describes detonation and pre-ignition the best i have heard...
and puts all of the thread posters (including myself) to shame...lol
clearly pre-ignition is most dangerous...
the text describes detonation as potentially not disasterous...

i would like to see more pictures of damaged internals...
maybe there is more evidence out there for the Radiant Energy taking place
for now...that texts description is most complete...
however...the blocks resonating at a 6200hz or whatever frequency it is...
that just doesn't seem like something fuel could produce outside of pre-igniton...
i just dont see sudden combustion of unburnt fuel ATDC as being a viable source for that kind of energy and pinging...
if in fact it can be produced ATDC...i would say it can...though i dont have enough experience tuning motors...
something still rings true that there is something else happening in certain conditions
i have heard it...and my first reaction and present thought is that fuel could not do that...

[onegammyleg]

molecule

Ok , whatever , radiant energy , fairy dust , we dont care.(and ime not going to debate this topic any more)



Many if not the vast majority of visitors to this forum back up their ideas with scientific experimentation and use thier own cash to finance their thoughts.

So how about this for an idea.

If you think radiant energy is the key to this amazing power , how about you , out of your own pocket , build a radiant power engine.
Go get a loan from the bank , sell your house (if u have one) and all that you have to finance this project.
If you are SO convinced that radiant energy is the source of unlimited power then there should be no reservation on your part to take up this challenge and make a car run on it.

When you get it working , present it to two , independant , 3rd party qualified observers and I will gladly drop my shorts so you can give me a good kick in the kaboose.

So there you have it , prove me wrong.
Prove to everyone here that I am ignorant person. (as you have challenged)

But you know what , I believe that you , just like Tesla and all the others , will come up with some reason why you don't come up with the goods.

Ime expecting , you to reply with some comment like , ¨why should I prove it to you¨ , ,, or , you will tell us to ¨prove it to you that it doesnt work¨., or some other lame exscuse not to develope anything.

[rh77]

I just switched back to 87-octane because of the colder weather

More $$$ saved...

RH77

[molecule]

you have heightened the claim of my belief beyond...
i merely stated what i have read about tesla and his accomplishments...
i believe 100% in the radiant energy...
do i believe that the E.V. Gray motor and the Tesla motor work...???
i'm skeptical...
you must understand something though...Teslas alleged discovery of radiant energy has nothing to do with a motor...
it was not internal...it was in open air...a circuit board of sorts...and a spark gap
his motor circuit had an antennae about 6 feet long...
i'm not in the least suggesting running a motor on alleged radiant energy from spark energy in an internal combustion engine...
ALL I AM SAYING is that maybe we can eliminate the possibility of detonation
that is all i have been saying from the beginning
you need to reread my first post
i am not talking about harnessing radiant energy to power a motor
though who wouldn't if we can...???

stop being such a weeny...you think i give a rats *** about you...???
honestly...be a little more forthright with your nobility...
oh watery being...with no theory of life...

the thing that i believe makes you ignorant is your willingness to jump to conclusions...
to take someone elses work and make it your own for plight or quarry
to stand as a judge who cannot be judged

you sound like i made this thread just to invoke your reply
you could have just watched...
someone with the confidence of their beliefs surely would not need to display them just to sound smart....???? or would they...???

**** man...you wont even engage in conversation
all you do is bark orders
ignorance is not being able to find common ground
to rule out another being for difference
you have no concept of energy and what constitutes your being
you THINK you know...but you fail to display respect for it here
you have segregated me into a space in your mind where all bad things go
i'm not saying you cant disagree...
but nobility finds a way to understand
where i understand you...but you do not understand me
you look down on me...where i do not look down on you...
i shun you....when you cannot look past the difference...
respect is earned my friend
take a look who made the decision to open fire in a personal way
my mistake was to feed that fire with response
you cannot (or have not shown the ability to) differentiate the practical use and necessity to direct energy towards a positive outcome...
you will just end up a sour bastard if you do
and this i speak from experience and can back up with experimentation
energy is life...and altitude is life insurance...
how high are you...???

[onegammyleg]

Molecule -¨take a look who made the decision to open fire in a personal way¨

Umm , take a look dude.
You responded to my first post on this subject at post number 5 with ¨your a fool and a liar.¨
On post 6 you said ¨**** man¨
Post 6 ¨oh and i dont care how much f'in¨
Post 13 ¨but ****¨
Post 22 ¨i think you are a fool¨
Post 39 ¨you think i give a rats *** about you.¨
Post 39 ¨**** man.¨
Post 39 ¨sour bastard¨

So I did take a look , and your the agressor.

And like I said , prove what you say with verifiable proof or just B quiet.

[red91sit]

I think it might be best if you leave Molecule, or atleast realize that if you come on here asking questions, you shoudln't call people liars, fools, and bastard's when they try to help you...

I really don't understand your purpose here, we already all know what detonation is and how to avoid it. Exactly what is it your wondering? BTW all that philisophical stuff really has no use here.

[psyshack]

Wow!!!!!