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Discussion Starter · #1 ·
Does anyone know of any type of fuel that could produce a higher flame propagation than gasoline without raising compression?
 

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tegboy1342 on Feb/09/04 said:
Does anyone know of any type of fuel that could produce a higher flame propagation than gasoline without raising compression?
Yes. But no-one uses it or talks about it because the economy would fall apart.


Lol, seriosuly, if there was something better than gasoline available taht would work in our engines, dont you think someone would have mentioned it by now?
 

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no i make my own fuel that is cheaper and is gaurenteed to make ur car run 150% stronger, yet i have proven to be more reliable than gasoline....i am a gazillionare


seriously tho, every car company in the world has a team of engineers trying to solve this problem.
 

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i know what he's talking about. people have used modified fuels in the past that have stupid-high propogation speeds... this allows for much less ignition advance.

if this is your goal, they're called fast-burn engines. nowadays, most people modify the head (and combustion chamber as a whole) to create fast-burn engines with extreme flame propogation, and use good-ol' gasoline. (but it generally requires some compression increase)
 

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Well, there's propane powered vehicles. I dunno about no dang-old doggone flame proper-gayshun or nuthin.

Maybe my friend Hank Hill would know.

I just know you'd need a number of modifications to turn your engine into a propane engine. I wouldn't even know the advantages or drawbacks.

But I agree, i think the lack of alternative fuel vehicles should tell you something about their viability in the real world.
 

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turbulent flame speed increases can be influenced by:

mixture motion and AF ratio (eg. lift swirl, reverse tumble swirl, direct fuel injection)

combustion chamber shape (eg. lean burn compact combustion chambers like the pentroof in our Tegs), as DaBoyNBlu stated.


and as you suggest fuel composition (methanol-natural gas or liquified petroleum gas with usual hydrocarbons for cold start). Heavier fuels have faster flame speeds.

from this site:

99 octane (R + M/2) methanol runs an average of 0.43 m/sec measured stoichiometric turbulent flame speed compared to 86-94 octane (R+M/2) unleaded gasoline's 0.34 m/sec, all things being equal.

However, methanol combustion produces formaldehyde which is known to cause cancer and is not removed by your cat until it has come up to temp. I wonder if the CART boys (methanol turbo engines) wear protective masks in the pits or if they use a formaldehyde scavenge mechanism?

Methane 120 octane (R+M/2) and propane 104.5 octane runs a stoichiometric turbulent flame speed of 0.45 m/s.

I guess the latest hype is using hydrogen powered engines which produce water as the only emissions output (at least GM wants you to know that's what their doing but they aren't the only ones). The website discusses the hydrogen filled air ballons and the Hindenberg disaster.Yikes.

Bush's clean air bill is based on pushing these alternatives. Maybe a kick in the ass to high inertia status quo lovers and dinosaurs like GM.
 

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Discussion Starter · #12 ·
thanks for the help guys. since peak cylinder pressure falls around 14 degrees atdc b/c of the chemical limits of the fuel, i figured that if you can push the piston down past 14 atdc then you would obviously gain considerable power. and by the way, methanol has a lower flame propagation than gasoline, it just burns much cooler and has a higher resistance to detonation...
 

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Some people try to spread out the peak cylinder pressure over several crankshaft degrees but have a lower overall absolute peak value.

the LMP turbo diesel racing engines run it like that with big torque at low low rpms....great for driveability out of the corners...they do that, instead of trying to shift the peak cylinder pressure location to a later crankshaft degree ATDC.

why? lower cylinder temps. with less detonation risk.

Ricardo Motorsports is building a turbo diesel racing engine to run in LeMans.

if you read the Shell Optimax Gold fuel hype they say with their cleaning additives in their fuel, they can run an earlier combustion propagation and also allows for the max cylinder pressure to occur later ATDC for more kick down on the piston at a better rod to crank angle (I guess they claim the combustion chamber shape is cleaner and keeps it's shape without deposits and the mix is more homogeneous and so you get an earlier burn start up and the burn is slower with their 98 octane rating in Asia so the completion of burn isn't until later in the ATDC)...sort of too much of a good thing in my books (ie. hyped to the max. )...if all else fails, just say you are the official fuel supplier to the Ferrari F1 team and that's why your fuel is "worth it"...
 

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Some FSAE teams run Ethanol 85 (the only legal fuel in the competition besides gasoline). It is capable of producing a bit more power but making the transition is a nightmare because it eats many types of seals and gaskets. Plus, it would be tough to get a hold of and about as legal as removing your headlights and installing machine guns.

If your car is street driven stick with pump gas!
 

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MichaelDelaney on Feb/10/04 said:
Bush's clean air bill is based on pushing these alternatives. Maybe a kick in the ass to high inertia status quo lovers and dinosaurs like GM.
Actually GM was the first to suggest cleaner vehicles. Low gas prices in the U.S. enable soccer moms to drive their empty urban assult vehicles all over the place. The low gas prices are due to government control of gas taxing. Low gas taxing is due to the fact that voters won't vote for a candidate who wants to raise gas taxes (until Bush maybe). GM just builds what customers demand, just like any company that want's to be around for a while. So, moral of the story, wasteful consumers should get a kick to the ass first. Just thought i'd throw a bone to the company that signs my paychecks.
 

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damn urban assualt vehicles lol, Adam I agree with your post...

Michele
 
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