Gas vapors?

[gungfudan]

Has anyone converted their carburetor engine to run on gas vapors.

 

[RonD]

No, it is one of those simple science automotive MPG enhancers, that read well but don't work.

It starts with what sounds like reasonable science, "gasoline vapor" will release more energy when burned than "liquid gasoline", but it isn't true in automotive use, it just reads like it should be true, lol.

Carburetors are less efficient than fuel injection for a few reasons.
One is that as the air passes the jets fuel is sucked out and fills the intake with an air/fuel mix, there is alot of surface area in an intake manifold and some of that air/fuel mix sticks to the sides of the intake, so fuel is unused, but no longer in the tank, lol.
(vapor injection would suffer the same fate)

Another is that as long as an engine is pulling in air, fuel is being sucked out of the jets, so when coasting you are burning fuel.
(Same thing with vapor)

Fuel injectors are located next to the intake valves, so most of the air/fuel ends up in the cylinder not coating surfaces, better MPG

Fuel injectors are shut off when coasting, general parameter is when your foot is off the gas pedal(TPS at 1volt), the injectors are shut off until engine RPMs drop to 1,100, then injectors are restarted at idle level, better MPG.
It is better to coast down a hill in gear so RPMs are higher and fuel injectors are off, than coasting in neutral with engine idling , better MPG

The Feed back system with O2 sensors reading rich/lean condition also aids MPG by doing on the fly adjustment of air/fuel mix.

Fuel injection works much better with the Feed Back system, Feed Back Carbs didn't do as well, but also had the other drawbacks.


The science of energy conversion is not simple but does have some simple rules, the "vapor injection" idea is fine except it won't improve MPG.
Same with hydrogen injection, another one that reads good but can't improve MPG.

 

[BRUTUS_T_HOG]

Your engine already runs on gasoline vapor. Liquid fuel does not burn.

If you are talking about a wood gasifier or hydrogen you have nothing to gain over gasoline in my opinion.

There is CNG and LPG systems also. What exactly are you referring to?

 

[gungfudan]

http://m.youtube.com/results?q=gas%20vapor%20system&sm=1

Watch some of the videos. I am not saying I believe this or buy into it. I research things when I hear about them and before trying them. I am asking for facts, myths ect.....

 

[RonD]

Gasoline has a stoichiometric air/fuel ratio of 14.7:1
This means 14.7 parts, by WEIGHT, of air; and 1 part of gasoline, by WEIGHT, when burned, will have 100% combustion, all of the air and all of the fuel will be consumed.

Since this is by WEIGHT, the pre-vaporized fuel, or atomized fuel(injectors or carb) requires the same amount of fuel for the same ratio.

The "fuel vapor" idea is based on VOLUME not weight, which is why it reads well, lol, but in practice it can't work as described because you still need the same weight of fuel to get the correct ratio.

A gallon of gasoline has X amount of energy stored in it, if burned at 100% efficiency(14.7:1) there is nothing you can change in the combustion process to increase the energy available in that gallon of gas.
A leaner fuel ratio is more efficient but over time will melt pistons.

Gas engines run at 25%-30% thermal efficiently, this means that 70%-75% of the fuel consumed is wasted in heat generation, which isn't used to drive the wheels.
50% of that heat goes out the exhaust pipe, 50% to the cooling system.

So you are using less than a 1/3 of the energy in a gallon of gas to drive the wheels, over 2/3s is used to heat up the world, lol.

This is where engine designers spend most of their time, trying to increase thermal efficiency.

Diesel engines run at 35%-40% thermal efficiency, direct injection turbo diesels can get up to 50% efficiency.

 

[alfacliff]

the fuel injection system on the older Alfa Romeos injected the fuel into the intake at 600 psi or so. thaqt would probably be concidered vapor.
somje of the first gas engines used a vapro system, like the Wright Brothers flyer, a box with baffles that gas dribbled into and was heated by the engine as air was drawn through the box. dosnt that seem efficient and safe?

 

[kevinbmx77]

No, it is one of those simple science automotive MPG enhancers, that read well but don't work.

It starts with what sounds like reasonable science, "gasoline vapor" will release more energy when burned than "liquid gasoline", but it isn't true in automotive use, it just reads like it should be true, lol.

Carburetors are less efficient than fuel injection for a few reasons.
One is that as the air passes the jets fuel is sucked out and fills the intake with an air/fuel mix, there is alot of surface area in an intake manifold and some of that air/fuel mix sticks to the sides of the intake, so fuel is unused, but no longer in the tank, lol.
(vapor injection would suffer the same fate)

Another is that as long as an engine is pulling in air, fuel is being sucked out of the jets, so when coasting you are burning fuel.
(Same thing with vapor)

Fuel injectors are located next to the intake valves, so most of the air/fuel ends up in the cylinder not coating surfaces, better MPG

Fuel injectors are shut off when coasting, general parameter is when your foot is off the gas pedal(TPS at 1volt), the injectors are shut off until engine RPMs drop to 1,100, then injectors are restarted at idle level, better MPG.
It is better to coast down a hill in gear so RPMs are higher and fuel injectors are off, than coasting in neutral with engine idling , better MPG

The Feed back system with O2 sensors reading rich/lean condition also aids MPG by doing on the fly adjustment of air/fuel mix.

Fuel injection works much better with the Feed Back system, Feed Back Carbs didn't do as well, but also had the other drawbacks.


The science of energy conversion is not simple but does have some simple rules, the "vapor injection" idea is fine except it won't improve MPG.
Same with hydrogen injection, another one that reads good but can't improve MPG.

So when you down shift to slow down the fuel injectors shut off, i feel like this may solve something I've been wondering about. Sometimes when i downshift to slow down, ill push the clutch back in and the truck will die, could that be injectors not turning back on soon enough? Or maybe timing being off alittle?

Sent from my SM-G920P using Tapatalk

 

[adsm08]

No.