Gasoline VAPOR?

[Hersbird]

I think what you get with gasoline vapors is what was a 200hp (or whatever) motor making 20hp instead. It does mean it will be running wide open so limiting throttle body losses, and it can run really lean (which probably puts it way outside of allowable emissions). So a regular fuel injected (and especially a direct injected) car could also easily make 120 mpg IF you were willing to live with 20hp and tailpipe emissions be dammed.

[Ecky]

Originally Posted by Hersbird

I think what you get with gasoline vapors is what was a 200hp (or whatever) motor making 20hp instead. It does mean it will be running wide open so limiting throttle body losses, and it can run really lean (which probably puts it way outside of allowable emissions). So a regular fuel injected (and especially a direct injected) car could also easily make 120 mpg IF you were willing to live with 20hp and tailpipe emissions be dammed.

This stands to reason.

[racprops]

Sorry it does not stand to reason:

“I think what you get with gasoline vapors is what was a 200hp (or whatever) motor making 20hp instead. It does mean it will be running wide open so limiting throttle body losses, and it can run really lean (which probably puts it way outside of allowable emissions). So a regular fuel injected (and especially a direct injected) car could also easily make 120 mpg IF you were willing to live with 20hp and tailpipe emissions be dammed.”

If what is written is correct, the engine is only able to make use of 30% of the fuel fed by a carb Throttle Body Injection, Turned Port Injected and even Direct injection.

All these systems are gasoline droplets trying to convert to vapor. There is NO time for this to happen with in the combustion cycle.

SO If the fuel in converted to 100% vapor and then fed to the engine, it is said to burn much faster than any standard system and there is NO need to throw 100% of current fuel feeds to GET that 30% power making vapor.

Direct injection has already shown it to be a bad idea, unless YOUR selling the intake valve cleaning services which can be a new money maker for car dealers.

They still have the same problem getting the fuel to vaporize.

Pumping Loses are a minor problem so yes a wide open throttle is a good idea…if it can be done vapor feed might become the power controller like the fuel feed in in diesels.

Rich

[Ecky]

I'm not saying you're wrong, but I'd like to know what you're basing these assertions on.

Originally Posted by racprops

If what is written is correct, the engine is only able to make use of 30% of the fuel fed by a carb Throttle Body Injection, Turned Port Injected and even Direct injection.

Based on?

Originally Posted by racprops

All these systems are gasoline droplets trying to convert to vapor. There is NO time for this to happen with in the combustion cycle.

How long is needed?

How quickly does a micro-droplet of a volatile hydrocarbon take to vaporize when it's suspended in a 3000° kelvin gas?

EDIT: I just looked up the auto-ignition point of gasoline - it's 280°C, or 536°F.

Originally Posted by racprops

SO If the fuel in converted to 100% vapor and then fed to the engine, it is said to burn much faster than any standard system and there is NO need to throw 100% of current fuel feeds to GET that 30% power making vapor.

What's interesting to me is that diesel engines burn their fuel by compressing it until it explodes - 100% ignition, instantaneously.

Diesel has around 15%(?) more energy content per volume of fuel.

At work, we have a Rav4 gasoline, and a Rav4 diesel, both with similar engine sizes. The diesel gets around 15% better fuel economy.

If the diesel is getting around 35mpg, should not the gasoline version get only 10mpg? What am I missing?

Originally Posted by racprops

Direct injection has already shown it to be a bad idea, unless YOUR selling the intake valve cleaning services which can be a new money maker for car dealers.

Mazda's direct injection engines have been torn down north of 200,000 miles, and the valves have still been essentially clean. Evidently it depends on the implementation.

Originally Posted by racprops

They still have the same problem getting the fuel to vaporize.

Based on? What manufacturers publish suggests incomplete combustion is 2% or less. Are we being lied to?

I'm not suggesting there isn't gain to be had by improving vaporization, but we have the engine makers saying <2%, and you saying 70%. And, we have examples of engines that do not have vaporization problems which show only marginal improvement.

[Ecky]

Doing a bit of math using vaporization rate calculators:

Assumed injection amount - 0.02g per cylinder per cycle
Molecular weight of gasoline - 100.2g/mol
Mass transfer coefficient - 0.18 m hr

Area of liquid surface - let's assume the gasoline is squirted as a single droplet, and not as a spray. We have 0.000200 mol of gasoline, which, if in a sphere, would have a volume of 0.00448 liters. The surface area of a sphere containing 0.00448 liters is ~0.00096 square meters.

Vaporization pressure of gasoline - 9psi or 6.8kpa

Temperature - I put in 2500c.

I plugged these values into a few engineering calculators, and got numbers that were zero, rounded to the nearest tenth of a millisecond.

If a crankshaft is spinning at 2000rpm, that's 33 revolutions per second, or 12,000 degrees of rotation per second. Or, 1 millisecond per 12 degrees of rotation.

The vaporization worst case scenario is less than 0.1 millisecond. Assuming your injector just dribbles the fuel in, in a single large blob.

As to how this plays out in practice is another matter. This is my best attempt at academic honesty on the topic.

[racprops]

How much does 1 gallon of liquid gasoline displace as a vapor? The saturated vapor volume of an average gallon of liquid gasoline when fully evaporated is 160 gallons of vapor at 60° F and sea level. When you convert 1 gallon of gasoline into 160 gallons of highly combustible fuel vapor you increase your nation’s fuel supply by 16,000% (16,000% of 1 is 160). If you paid $5 for just one gallon of liquid gasoline you would actually only be paying $0.03 (3 cents) per gallon of fuel vapor.

From: https://presscore.ca/news/how-to-con...bustible-fuel/

SO You can get a LOT of vapor....out of a gallon of gasoline.

[racprops]

I'm not saying you're wrong, but I'd like to know what you're basing these assertions on.

Quote:

Originally Posted by racprops
If what is written is correct, the engine is only able to make use of 30% of the fuel fed by a carb Throttle Body Injection, Turned Port Injected and even Direct injection.

Based on?

https://en.wikipedia.org/wiki/Engine_efficiency
Gasoline (petrol) engines

Modern gasoline engines have a maximum thermal efficiency of more than 50%,[1] but most road legal cars are only about 20% to 40% when used to power a car.[2][3][4][5] Many engines would be capable of running at higher thermal efficiency but at the cost of higher wear and emissions.[6] In other words, even when the engine is operating at its point of maximum thermal efficiency, of the total heat energy released by the gasoline consumed, about 60-80% of total power is emitted as heat without being turned into useful work, i.e. turning the crankshaft.[7] Approximately half of this rejected heat is carried away by the exhaust gases, and half passes through the cylinder walls or cylinder head into the engine cooling system, and is passed to the atmosphere via the cooling system radiator.[8] Some of the work generated is also lost as friction, noise, air turbulence, and work used to turn engine equipment and appliances such as water and oil pumps and the electrical generator, leaving only about 20-40% of the energy released by the fuel consumed available to move the vehicle.

Quote:

Originally Posted by racprops
All these systems are gasoline droplets trying to convert to vapor. There is NO time for this to happen with in the combustion cycle.
How long is needed?

How quickly does a micro-droplet of a volatile hydrocarbon take to vaporize when it's suspended in a 3000° kelvin gas?

EDIT: I just looked up the auto-ignition point of gasoline - it's 280°C, or 536°F.

Quote:

Originally Posted by racprops
SO If the fuel in converted to 100% vapor and then fed to the engine, it is said to burn much faster than any standard system and there is NO need to throw 100% of current fuel feeds to GET that 30% power making vapor.
What's interesting to me is that diesel engines burn their fuel by compressing it until it explodes - 100% ignition, instantaneously.

Diesel has around 15%(?) more energy content per volume of fuel.

At work, we have a Rav4 gasoline, and a Rav4 diesel, both with similar engine sizes. The diesel gets around 15% better fuel economy.

If the diesel is getting around 35mpg, should not the gasoline version get only 10mpg? What am I missing?
https://en.wikipedia.org/wiki/Engine_efficiency

Diesel engines

Engines using the Diesel cycle are usually more efficient, although the Diesel cycle itself is less efficient at equal compression ratios. Since diesel engines use much higher compression ratios (the heat of compression is used to ignite the slow-burning diesel fuel), that higher ratio more than compensates for air pumping losses within the engine.

Modern turbo-diesel engines use electronically controlled common-rail fuel injection to increase efficiency. With the help of geometrically variable turbo-charging system (albeit more maintenance) this also increases the engines' torque at low engine speeds (1,200–1,800 rpm). Low speed diesel engines like the MAN S80ME-C7 have achieved an overall energy conversion efficiency of 54.4%, which is the highest conversion of fuel into power by any single-cycle internal or external combustion engine.[9][10][11] Engines in large diesel trucks, buses, and newer diesel cars can achieve peak efficiencies around 45%.[12]


Quote:
Originally Posted by racprops
Direct injection has already shown it to be a bad idea, unless YOUR selling the intake valve cleaning services which can be a new money maker for car dealers.

Mazda's direct injection engines have been torn down north of 200,000 miles, and the valves have still been essentially clean. Evidently it depends on the implementation.


https://duckduckgo.com/?t=ffab&q=Whi...lves%3F&ia=web
Lots of reports…


Quote:
Originally Posted by racprops

They still have the same problem getting the fuel to vaporize.
Based on? What manufacturers publish suggests incomplete combustion is 2% or less. Are we being lied to?

Perhaps:

https://strutdaddys.com/the-truth-ab...ur-gdi-engine/



I'm not suggesting there isn't gain to be had by improving vaporization, but we have the engine makers saying <2%, and you saying 70%. And, we have examples of engines that do not have vaporization problems which show only marginal improvement.

A standard vaporization problem was vapor locked fuel systems….

There are hundreds of stories going back over 80 years from the Fish Carb, to Tom Ogle…

https://duckduckgo.com/?q=Historial+...&t=ffab&ia=web

[cRiPpLe_rOoStEr]

Originally Posted by racprops

if it can be done vapor feed might become the power controller like the fuel feed in in diesels

IIRC that's how some dedicated-CNG and propane fuel systems operate on forklifts.

[Ecky]

Originally Posted by racprops

How much does 1 gallon of liquid gasoline displace as a vapor? The saturated vapor volume of an average gallon of liquid gasoline when fully evaporated is 160 gallons of vapor at 60° F and sea level. When you convert 1 gallon of gasoline into 160 gallons of highly combustible fuel vapor you increase your nation’s fuel supply by 16,000% (16,000% of 1 is 160). If you paid $5 for just one gallon of liquid gasoline you would actually only be paying $0.03 (3 cents) per gallon of fuel vapor.

From: https://presscore.ca/news/how-to-con...bustible-fuel/

SO You can get a LOT of vapor....out of a gallon of gasoline.

160 gallons of gasoline vapor has the same energy content as 1 gallon of liquid gasoline - minus the energy needed to vaporize it.

Engines already turn 0.02 grams of liquid gasoline into 0.02 grams of vaporized gasoline per injection event.

[racprops]

Sorry NO they don't The burn cycle is too slow to fully use 100% of the fuel other wise we would be told to cut out the cats as they are no longer needed.

Rich