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ZooTech wrote:

Shiv wrote:But why would it be two different states?

Just because it's getting sprayed into the cylinder doesn't mean it's a gas.

And once it was combusted, it goes out the exhaust.

The injectors atomize the fuel, they don't convert it to a gas. Atomization is necessary for a quick and even burn, otherwise you end up with unspent fuel and cylinder hot spots.

What he said, and most of the volume of the engine (1000cc) is actually gas (air). And you also need to remember that the actual combustion takes place at the end of the upstroke, meaning the gas and atomized fuel is compressed, then detonated.

While it's not entirely related....here's a good link to a gasoline FAQ I found a while back.

http://www.faqs.org/faqs/autos/gasoline-faq/part1/

tells you all you need to know about how gas is involved in combustion and whatnot.

gas does ignite as a liquid, ever throw a match on gasoline? yeah there is some poof as the vapors around it go up, but after that its just burning liquid fule. however when you introduce atomized (creates an excessively high surface area per volume) fuel to hot cobustion chamber(from previous explosion) then there will be a rapid vaporization as well, which would help to ignite any still liquid gas. so yes they do burn at different rates at the same time, why do you think many engines have two plugs per cyl? I belive new hemis do this cause the domed head is not as efficient at, well, anything as the pent roof design. However the difference between gasoline with an excessively high surface area (burnable area) to volume ration and as a vapor (entire volume IS surface area, sort of) is relatively low, and when compressed some of the actual gassified gas will compress back down to a liquid with the pressure. in effect you could possibly see this as good because the initial vapour explosion gets the piston moving and the slightly slower liquid fuel continues the process further on in the stroke. then again this is all in maybe milliseconds or less, I mean say with a 12k rpm speed on a twin then the piston moves down 6k times a minute, or 100 times per second, so ok thats .01seconds that is the entire power stroke under this situation. then again probably 30% of the fuel is not actually burned through this and keeps going out to the cat to burn up there or it leaves the exhaust pipes with some flame.... which is probably where more of the gas that is less atomized goes. this of course is wasted gas.

I'm sure I read somewhere (credible) that a pool of gasoline only burns as the surface vaporizes to a gas, and that the actual liquid does not ignite (pour gas onto a match and it will extinguish, etc).

It was a long time ago and is one of those things I never questioned or had reason/need to test or reresearch

pouring gas onto a match will remove all the exygen from the heat, therefore no flame. the flame happens at the point where the heat and fuel and oxygen come together, without any one peice there is no combustion. so in a sense yes it will only burn at the surface, where it comes in contact with the oxygen. atomized gasoline has as much surface area per volume as gas can have, meaning that amost all of the volume of gas is in contact with the oxygen. the volume of gas is the fuel potential, I guess you could say the surface area is the available fuel.

Gasoline does evaporate very rapidly though, so I could see the 'only vapors' part being true.

I wish I knew more about science...or well chemistry. Know more than enough biology to last me a life time and getting more and more crammed into my head everyday.

Gasoline will not burn as a liquid, its the vapor that burns. Gasoline gives off lots of vapors since it evaporates rapidly. When the vapor starts burning the heat from the flame causes the liquid gasoline to evaporate even faster feeding the fire.

The atomized fuel that enters a cylinder turns to vapor extremely rapidly when compressed, by the time the cylinder hits the top of the compression stroke all of the fuel has turned to vapor and will readily burn when it hits the spark.

The combustion process in the cylinder is not an explosion, its a controlled burn, just like a gun when it fires. The burning of the fuel causes tremendous expansion of the mixture of gases in the cylinder from the heat and forces the piston down

Im not being funny, but is this a wind up, Jeez... 18litres of fuel, 1 liter of engine, your having a laugh....
1000 CC = 1000 militre cubic capacity = bore and stroke of engine...lengh of cylinder width of cylinder on this bike would be all four cylinders = 1litre of space, length of stroke, shorter the stroke faster the revs, etc, basic maths here guys...

fuel mixture is atomised and squirted in the the cylinders ignited by the sparkplug Bang....power ...
Inlet valves suck the fuel in, fuel is ignited exhaust lets spent gasses out..
its not rocket science, actually rocket science is simpler!

I've seen two fires involving 10 gallon gas storage cans. The tank that was full, caught fire and was highly volitile. The tank that was empty, exploded withan incredible amount of energy. Which supports the fact that it is the fumes that are the most dangerous when combined with O2.

Shiv wrote:You sure it vaporizes it? I'm pretty sure that the fuel while under pressure would be very volatile and would have no problem combusting in a liquid state.

It is definitely vaporized. That is the primary function of the fuel injector or carb.

In order to completely burn the fuel charge in a cylinder, you must have the stoichiometric (optimum) balance of fuel and air. For gasoline engines, this is 14.7 parts air to 1 part fuel. If you increase the amount of fuel in the ratio, it's called a rich mixture. At some point, you'll reach the level where there is not enough air in the ratio to ignite the mixture. If you've ever had a carb that was running rich, you'd know that it's long before the point where the fuel is entering the cylinders in a liquid state.