Quote:
Originally Posted by racprops
Found this:
At what temperature does gasoline vaporize?
What kind of heat would have to be applied to a closed circut container to vaporize the gasoline inside?
I'm an amature MAD scientist
Update: OK I'll spill. Gasoline carburetors are about 30% effficient. A gasoline engine CANNOT burn a liquid fuel. The carb turns the fuel into a spray, tiny droplets that do ignite but ver ineffeiciently. That why all the smog pump carp. To reburn what passed through. These are called hydrocarbons. OK back to the spill. If the gasoline can be turned from a liquid gas into a true vapor, which is MUCH more explosive than liquid gas, it will burn at 100%. The result of that is a shocking improvement in fuel mileage. Carbs have been built. IN 1936 Charles Pogue built one that milled out an amazing 200 mpg. Interestingly enough his shot misteriously burned down after he refused to sell it to an oil company. Its no secret though. The plans still exsist. You can find sketches on line. There are three types. heat, cold and electric vaporization. All of which improve mileage from 30 to 100%... a V8 that gets 60-80 mpg? its already been done.
AND:
fuel boils between 104-401F and from what I've read it vaporizes at 450F, and will self ignite at 460-572F. i have also read up on this and am currently thinking of building my own vapor carb, mainly because i am getting around 10 mpg on my old school carb.I'm going to start testing at 50F to see how the gas reacts and take it farther from there. i also thought about using water. the engine will only get you to 250F before it over heats if it hasn't done so by that point, but it might work. so i will see how far i can get with other methods. from what I've read we can't sell what we invent so if i find a way to get it off the ground I'll use it on my own vehicle and share the proven facts with others. just remember that the vapors are really explosive, you don't want to miss calculate and blow up your test facility. also to get 100mpg i saw something that says you would need an air/fuel mix of around 75-1.
AND:
The flash point of diesel fuel is 100 deg. F. for type 1-D fuel. And 125 deg. F. for type 2-D fuel. And 130 deg. F for type 4-D fuel.
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I know where you got that post because I had argued with the poster years ago. He had high regard for his own opinions as these people have a tendency to do. I have said it before and I'll say it again, if you look at the particulars of the Pogue "experiment" you will see a lot of ecomodding techniques were used to achieve the so called 200 mpg. And more that were not made public. So what if you can get 200 mpg from a car that was gutted and lightened and was run at only 40 mph? The FreedomCar program from the 90s had gasoline powered vehicles that got 60-80 mpg but with body construction that did not meet safety standards for collision and with engines that did not meet emissions standards. None needed to use vapor carburetors. The more realistic goal of 50+ mpg with fully vetted construction and emissions control is already within manufacturers grasp.
And your continued belief that only 30% of the fuel is burned is erroneous. The poster MAD Sceintist ( he spelled his name that way because of the " i "before "e" thing - really ) would spout that belief even after I produced dozens of research papers that show through high speed photography and heat measurements that 98% of the fuel is burned before BDC ( bottom dead center).
Now, there is something to be said about vapor phase combustion, but as Oil Pan4 has pointed out, it is only in the single digit range of advantage. What you and many others fail to realize, is that heated gasoline vapors are more reactive. As the post on heated airplane carburetors indicated, something is happening that causes detonation if you heat your fuel mix under certain conditions.
In his book about the Mitsubishi Zero Fighter of World War 2, Subaru Sakai mentioned his part in finding an extra several hundred miles of range for his aircraft by leaning of the fuel mix. Though not mentioned in the book, an interview later indicated that carb heat was also used during cruise. When a pilot detected pinging, he would lean the engine. This would continue until the exhaust gas temperature would drop. This indicated the safe area to cruise lean. This allowed the Japanese Empire to strike targets in the Philippines from bases in Formosa ( modern Taiwan ).
The American Aviator, Charles Lindbergh, found out the same phenomenon a short time later and this allowed aircraft fighting in the expanses of the Pacific to gain an extra measure of range.
There is nothing magical about vapor phase combustion. It is well understood and has been used for decades in various applications. Vaporizing gasoline will gain you a few percent in efficiency because of the elimination of irreversible losses ( energy needed to vaporize the droplets ). The hot vapors do gain in reactivity which can allow you to run the engine with reduced ignition lead. This allows you another few percent in efficiency gain. The real gains come from running lean and being able to do so with reduced ignition lead time resulting in more torque production from the same amount of fuel. This results in reduced pumping losses too. Now you will see double digit percentage gains.
All the above is well known and taught at the university level. I can vouch for the theory holding true in various applications.