Two of my own Unicorn ideas?

[ps2fixer]

I thought of these ideas prior to becoming a member here, and since reading a lot and learning loads, I'm thinking these ideas are more myth than logical.

First one... I have always been told that fuel injectors are less efficent compaired to carbrator in the department of fuel atomization. Since then it seems the best MPG will be found on small engine powered cars which are fuel injected. Down side of carb was the fact you can't control it as well as fuel injection. This made me think fuel vaporization could be a real fuel saver. I have done some small tests with lawnmower engines and was able to get an engine to run on only fuel vapors, but it would die out after starting since it was sucking more at the higher rpm than starting so less air contact time with the fuel to get it to evaporate. Also pulling the intake though a liquid would restrict the air flow, which I would suspect would make the engine low rpm only.

Expanding on the idea after a while, I came across plans online (don't have link atm) of a chamber the designer called the vapor carbrator. The very basics is that it had a small pump which would cycle air though the chamber to get as much fuel in the air as possible. Then the top side of the chamber ran to the intake of the engine, along the way having a exhaust exchange to heat the fuel (and maybe the chamber?), a placed to add fresh air, regulate vacuum, etc. It seems to be an interesting idea, but the claims are reallllllyyyyy out there. Something like 200mpg in the 1950s using a 1930s v8.

Here is one of the cars I came across after the 200mpg v8 thing.... 376mpg car which has a chain drive and ran on vaporized fuel in 1976. Interesting read, but I think it is another one of these unicorns.

Big Oil conspiracy! 376 mpg Opel uncovered! | Hemmings Blog: Classic and collectible cars and parts
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Second one... Based on racing mojo... nitro boosts car power by tons which basically adds more oxygen allowing the engine to burn more fuel per power cycle, but this largely adds to temp which I didn't think much about before. The idea was to equip a car with an oxygen tank and run it as a boost to engine power expecting better MPG, and back then thinking the savings would bearly cover the oxygen tank refills. My new thinking is that MPG would be nearly the same giving no other factors are changed, just adding abilities for the engine to burn more fuel at a given rpm would lower rpm, but at a huge cost of having the intake butterfly closed more which of what I read is less efficent (basically having a v6 vs having a v4 in a small car). Only good thing I can think of is for using an extremely small engine and maxing out what it can do within reasion (including turbo) and the benefit could be viewed similar to a normal turbo setup but have further gains? Also note that the oxygen used would be huge, and wouldn't last a tank of fuel I suspect.

Just for giggles I played around with a tourch with LP + Oxygen setup to "fuel" a lawnmower engine. Basically adjusted for the best flame, knocked it out and stuck the nosel in to the carb area and pull started it with my other hand. In about 3 tries, the engine did fire up the gas, but it was a backfire which riped the pull rope out of my hands and puffed out of the carb. That was enough of that for me . Also to note, I think it was out of gas when I tried it and orignal plans was to just start it on it for a few secs just to see the thing run on it, no revs etc.


Just to make sure I'm clear, I view the above as 99.5% invalid myth with an extremely slim chance of having any type of benefit in any form, but comments should make things funny .

[NeilBlanchard]

If carbs are that good, then why do virtually all cars use fuel injection?

Internal combustion engines are limited by the Laws of Thermodynamics.

[rmay635703]

Actually a carb or throttle body can be basically as efficient as true direct injection but most cars didn't control the A/F well using carb tech which was designed for true mechanical ideot proof operation. AKA rich Not many bother with electronically controlled carburation which is basically what throttle body is.

Next the old hit and miss engines from before 1940 into the 1800's ran on vapors, every one. I can't say they were extremely efficient but it works just fine and is simple. The trouble with any kind of vapor system is that the carb will gum up with laquer if it actually vaporizes the fuel.

Something that did intregue me was the catyllitic carburator, something that may have been more efficient than FI. They explored it prior to using a CAT to clean exhaust, instead the cat cleaned the intake charge (sort of)

[ps2fixer]

Very interesting replies, didn't know anything about the laquer building up in vaporized systems or the fact engines where already designed to run on them. In my adventers of vaporization, i also tried 99% isopropyl alcohol and didn't have such luck, had a backfire that blew up my fuel container as well as a strong ringing in the ears. That was about the last time I did that type of stuff .

@Frank Lee

Sorry, the "mith" spelling is a result of playing games... it cooks the mind. Mith is short for Mithril as in Runescape - Mithril - The RuneScape Wiki - Skills, quests, guides, items, monsters, and more

Edited first post to correct spelling.

[Ryland]

Originally Posted by ps2fixer

First one... I have always been told that fuel injectors are less efficent compaired to carbrator in the department of fuel atomization. Since then it seems the best MPG will be found on small engine powered cars which are fuel injected. Down side of carb was the fact you can't control it as well as fuel injection.

Fuel atomization is dependent on fuel pressure and spray pattern, seeing as how most engines that you can compare side by side show both an increase in peek HP and lower fuel consumption, I'm not sure where you get the idea that a carburetor is better.

Here is one of the cars I came across after the 200mpg v8 thing.... 376mpg car which has a chain drive and ran on vaporized fuel in 1976. Interesting read, but I think it is another one of these unicorns.

Big Oil conspiracy! 376 mpg Opel uncovered! | Hemmings Blog: Classic and collectible cars and parts

One of the ideas behind vehicles like that, that vaporize the fuel is that they are not using all of the fuel, just the lightest part of it by bubbling warm/hot air up through it and pulling off the light flammable parts, then at the end of the test when the left over fuel is weighed or measured you have the slower burning parts left over, perfect for varnishing your wood work.
That car is also just part of an Opel shell that has been stripped out and had a very small engine installed, I suspect the whole thing weighs less then a 1,000 pounds.

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Second one... Based on racing mojo... nitro boosts car power by tons which basically adds more oxygen allowing the engine to burn more fuel per power cycle, but this largely adds to temp which I didn't think much about before. The idea was to equip a car with an oxygen tank and run it as a boost to engine power expecting better MPG, and back then thinking the savings would bearly cover the oxygen tank refills. My new thinking is that MPG would be nearly the same giving no other factors are changed, just adding abilities for the engine to burn more fuel at a given rpm would lower rpm, but at a huge cost of having the intake butterfly closed more which of what I read is less efficent (basically having a v6 vs having a v4 in a small car). Only good thing I can think of is for using an extremely small engine and maxing out what it can do within reasion (including turbo) and the benefit could be viewed similar to a normal turbo setup but have further gains? Also note that the oxygen used would be huge, and wouldn't last a tank of fuel I suspect..

VW has made 1.2 or 1.3L engines for the Golf that are gasoline with turbos and direct injection that get around 50mpg because of their small displacement needing less fuel at cruising speeds then the turbo allowing for higher power output when needed, Ford is doing the same kind of thing with the Eco-Boost engines.
Nitrous Oxide would be safer then pure oxygen because the Nitrous Oxide doesn't release the o2 until it's heated where pure o2 can burn your skin and room temp, either way I'd say that a turbo is a much better idea.

[gone-ot]

...there's a HUGE difference between ATOMIZATION 'efficiency' and ATOMIZATION 'quanity' control.

[Grant-53]

Evaporating fuel requires heat. This can be used to make the A/F mixture cooler and more dense. It's all part of the tuning or mapping process.

[mja1]

Originally Posted by Grant-53

Evaporating fuel requires heat. This can be used to make the A/F mixture cooler and more dense.

you mean "hotter" and "less dense"

[big shafe]

I've heard of SAE formula 1 design where they had injectors pointed up the runner towards the plenum. The idea was to have a better AF mixture. I've heard they were a bear to start, but this could be overcome with a second set of injectors that point down the runner to the intake valve, like a typical setup and then possibly wait until the engine reaches closed loop operating conditions.

I'd imagine the runner velocities would need to be sufficiently high at slower engine speeds.

[Grant-53]

Keep an eye open for direct cylinder injection engines becoming more common.