Water-Methanol boost

[GeneMO]

I have heard lots about "power fuel" , distilite, burning kerosene, etc. during the war due to gas shortages.

I am reading a book about the "Marianas Turkey shoot" in WWII. A fighter pilot in an F6F hellcat is chasing an enemy plane. Here is what the book says, " Dean, eager for another kill, shoved the throttle through "the gate": He pushed the lever past the safety-wire stop on the quadrant, engaging the water-methanol mixture that boosted his engine's power. The water injection feature added two hundred horsepower to the usual two thousand, accelerating the big Grumman beyound normal performance. It was good for only five minutes: Afterward, the Pratt & Whitney would begin to burn itself out.

Sorry for the long post, but thought this was interesting as this is technology that was invented when the H and M Farmalls were in their heyday.

Why are we not using this today? Not to the extreme that we burn out the engine, but maybe to squeeze more performance out of our gas?


Gene

 

[Anonymous-0]

Part of the problem with using the technology today is that carrying the weight of the water for combustion aid may negate benefit.

Also, water freezes.

I would also question what water would do to the engine long term even with pushing the so called limits.

 

[Anonymous-0]

Water injection to allow more power with low octane fuel was in use in the 1920's. A good example would be a steel wheel, flywheel start D John Deere feeding water from the over size top radiator tank into the intake so the engine could pull at full power on low octane distillate fuel.

Over the last 30 years or so I have seen bubbler type alcohol / water injectors that evaporate a bit of Water / alcohol mix and introduce it into the intake manifold of the engine.
In theory the evaporating mix will lower the intake air temp for a dense air mix, plus making the fuel air mix a little less apt to detonate with high compression and more ignition advance.

Any of you remember the Olds 215 turbocharged engine of the early 60's ? They used a water / alcohol injection system to fight full throttle detonation, when the engine was at max turbo boost. The fluid used was an alcohol / water mix, much like modern windsheild washer fluid which would not freeze in cold weather
Example of a water / alcohol injector.

 

[T_Bone]

Hi Gene,

I know they talk about it over on thedeiselstop.com for running at the drags on diesel engines. Like your article pointed out, it's only used for a short boost of HP when wound tight.

Too much of a good thing is not good for any engine. I never seen a engine torn down that ran meth/h2o so I really don't know.

T_Bone

 

[Anonymous-0]

One of the explainations I got was; Water has an infinity octane rating, also fills volume and raises compression;but "high" octane=no detonation. Try looking at high performance tractor pulls on Youtube, when they are winding up before launch the diesel cloud goes from black to grey, that is from water injection.

 

[Anonymous-0]

Methanol burns a lot cooler and makes better HP. It also makes a high performance engine last longer because of running cooler. That's why sprint cars, drag cars and monster trucks, etc. use it. Aircraft used technology that was way ahead of other industries. Especially in regards to engines.

 

[Gene Dotson]

The water injection (anti-detonation injection) was used to prevent the engine from destroying itself. The only purpose of the alcohol was to prevent freezing at altitude. Normal mixture was 70/30 in summer and 60/40 in winter.
The supercharger was capable of producing more boost than the engine could handle at full military power so water was injected to retard initial pressure buildup that will cause detonation. the five minute limitation was that was the capacity of the ADI tank.
The increase in power is due to the fact that water turned to staem actually has a higher pressure increase than burning gasoline... Gene

 

[MarkB_MI]

Nothing stopping you from using it today. It's just a means of preventing detonation in a supercharged or turbocharged engine. It's the supercharger that boosts the power, although there is some energy provided by the methanol.

 

[KIP in MX]

Not piston engine related, but we used to have Bell 206L helicopters in the late 70´s with Allison C-20 turbine engines that had a 3 gallon water/methanol tank. When the pilot was taking off, the engine would reach turbine outlet temp limits before he reached torque requirments, so pilot hit water/methanol switch and injected the mixture into compressor inlet for a few seconds. This dropped temperature enough to pull another 5-10% torque. Mixture was 3 parts water to one part methanol.

 

[sd pete]

Way back in the late 60"s and early 70"s I was in 2 Navy EC 121 squadrons. And we used it on take off to help keep the cylinder temp down. Those R3350"s could squirt a lot of fuel and water and alky mix on take off.

 

[Gene Davis (Ga.)]

Hot Rod magazine hadan article on building a system for use like this. They used a windshield washer pump set up with a vacuum operated switch I think and a rheostat to control the delivery rate into a nozzle made from a windshield washer nozzle pinched down somehow.

 

[dej(Jed)]

Engines love oxygen. The normal engine intake scenario can never supply enough oxygen for a complete fuel burn. Air is only about 18% oxygen.
Enrich that by means of porting or a super charger and you will get a better running engine.
Methanol is an OH configuration , while water has a 2H20 structure. Oxygen and hydrogen do wonders for combustion.

 

[John S-B]

Air is about 21% Oxygen, most of the rest is Nitrogen. You need at least 19% to function normally. Over 24% is not good either, it increases fire danger.

 

[buickanddeere]

Sorry dej(jed) but that"s only partially correct.
As some pp have stated. The water alcohol injection allows the supercharger boost to be increased without the engine suffering from detonation.
The methanol richens the mixture which also increases detonation resistance.
The proper amount of water absorbs enough heat during the compression stroke to prevent the air/fuel mixture from reaching it auto ignition temp.
Jets use water injection to absorb heat and limit power turbine inlet temps.
The water injection tends to steam clean soot, dirt and deposites from the engines.

 

[dej(Jed)]

Okay, I stand corrected. I should have specified that I was referring to conventional gasoline and diesel engines. I really haven't worked much around Jet engines.

 

[buickanddeere]

Atmospheric air is 20.9% oxygen no matter what the altitude/pressure.
H2O is H2O not H2O2
Water injected into a combustion chamber does not breakdown into it"s base chemical elements of Hydrogen & oxygen. It stayed bonded real tight.
In anycase the injected water is to lower temps in and after the combustion chamber.

 

[dej(Jed)]

Hey I said I would give you teh jet engine info, but now I don't agree! Compounds most certainly do break down when they ignite. Where do you think CO2, CO, SO, SO2 and Nox comes from? They are the bi products of combustion. No one put them in the fuel in that form. Also water is 2H20 you can't have H20, it would be chemically unstable. Yes, alcohol does cool, but it also is burnt as Hydrogen & Oxygen. At least that is what they taught us at Ohio State.

 

[buickanddeere]

CO, CO2, NOX, SO2 AND H2O are formed from combustion/oxidization.
How are you splitting water apart in a combustion chamber then turning around and re-combining it into water???
All the water is doing is absorbing btu"s of heat when flashing into steam. This limits the max temps in the combustion chamber.
The carbon and hydrogen in the alcohol bonds with oxygen, give soff heat and turns into CO2, H2O and a little CO. On it"s own alcohol burns too cool to heat N2 and make NOX as a by product of the heat/free oxygen and nitrogen under heat/pressure.

 

[Anonymous-0]

Ohio State, Should have known. Water in a real University chem101 class IS H2O, most encyclopedias, or even wikipedia confirms this. Oxygen does NOT burn, it promotes OXIDATION(chemical bonding).