ten percent water in one liter of petrol?

[Christ]

I'm just not sure how to go about emulsifying the fuel without wasting alot more energy than you're going to get back.

Plus, you'd have to test with all the other chemicals that are used in the emulsion to make sure that it wasn't just one of the chemicals or a component of more than one of them chemicals that makes the difference, which could get both dangerous and expensive quickly.

I used to have a diesel tractor that I burned old engine oil in... even the oil from the other tractor that always had water in it... yep, the creamy engine-killing goo. It never bothered the engine, but the filters would always clog earlier than normal from the goop in the oil.

Of course, I have no idea if it ran better, worse, or indifferent to the mixture, never tested, never cared.

[drew1d]

I can't speak for diesel engines. They're compression based combustion. (the pistons compress the air and fuel in a cylinder so much that it ignites, vs a compression AND spark of a gasoline engine.)

But water in an engine that has spark plugs is just bad news.

[jamesqf]

Originally Posted by Christ

So that coolant/oil mix never separated? Interesting...

Not in the maybe 5 years I kept the bottle around. There was some initial separation of water (maybe some that wasn't fully emulsified?), but after a couple of months or so it stabilized with maybe an inch of water at the bottom of the jug.

[Christ]

Originally Posted by drew1d

I can't speak for diesel engines. They're compression based combustion. (the pistons compress the air and fuel in a cylinder so much that it ignites, vs a compression AND spark of a gasoline engine.)

But water in an engine that has spark plugs is just bad news.

You got some sources/references to back that up?

I'm sure there are lots of turbo guys and FI guys in general that would love to disagree with you, and set up complete injection systems on their engines for the express purpose of injecting water/methanol into their engines, making more power and efficiency as a result of doing so.

[Christ]

Originally Posted by jamesqf

Not in the maybe 5 years I kept the bottle around. There was some initial separation of water (maybe some that wasn't fully emulsified?), but after a couple of months or so it stabilized with maybe an inch of water at the bottom of the jug.

I wonder what the means for storage properties of emulsified fuels?

Most primarily, whether the fuel will "gel" as diesel oils tend to.

[wagonman76]

Originally Posted by jamesqf

Or if you've ever had a cylinder head crack, so that coolant mixes in with the oil while the engine's running. Turns into this creamy gunk, which doesn't separate out again. I kept a bottle of it around for years, just to see if it would...

BTW, the naivity I meant wasn't about the diesel-water emulsion, but the idea that a high official wouldn't lie.

When I bought my 89 6k wagon, the guy said it had a blown head gasket. It had been sitting for 6 years after he parked it in the field behind his house. When I checked the oil, it looked perfectly normal. It wasn't until I ran it for a few minutes that the water mixed in and it was a milky mess. It wasn't new oil either, and upon driving it home the level didn't rise, so I know it had water in the oil when parked.

Yeah that was my first thought about lying high officials. Corruption by high officials seems like a weekly story in the paper around here. I'd believe them less than anyone.

Maybe it's different when mixed well enough, but normally water in the gas makes a car run like garbage, or not at all.

[Christ]

Originally Posted by wagonman76

When I bought my 89 6k wagon, the guy said it had a blown head gasket. It had been sitting for 6 years after he parked it in the field behind his house. When I checked the oil, it looked perfectly normal. It wasn't until I ran it for a few minutes that the water mixed in and it was a milky mess. It wasn't new oil either, and upon driving it home the level didn't rise, so I know it had water in the oil when parked.

Yeah that was my first thought about lying high officials. Corruption by high officials seems like a weekly story in the paper around here. I'd believe them less than anyone.

Maybe it's different when mixed well enough, but normally water in the gas makes a car run like garbage, or not at all.

That's the difference between emulsion and water in the tank.

When you get water in the tank, you get a very uneven distribution of water and fuel through each injector, and that causes stumbling and other problems, if you can even get it started. Once the water is emulsified to the point that it doesn't separate under normal circumstances (like when your oil turns creamy), that it can be used as fuel. The water is bonded to the oil in such a way that the fuel can still burn, heating the water molecules, making them unstable, turning them into steam, creating higher expansion ratios than normal fuels alone.

It's not a new concept by any means, but it is a novel one, for sure.

[drew1d]

Originally Posted by Christ

You got some sources/references to back that up?

I'm sure there are lots of turbo guys and FI guys in general that would love to disagree with you, and set up complete injection systems on their engines for the express purpose of injecting water/methanol into their engines, making more power and efficiency as a result of doing so.

Disagree, if they want.

Let me see if I got this right, inside the combustion chamber is a mix of gasses, for simplistic terms will say Fuel vapor and 02. With the right ratio, all the 02 and fuel are burnt, the gasses heat up and expand and push the piston.

Adding water vapor does a few things. It's material that expands when heated as well, and if it takes some of the heat away from the cylinder as it isn't the agent that is combusting. This slight amount of vapor expanding in the cylinder is what's giving the power? I wouldn't say that the water vapor isn't really chemically changing anything. It doesn't really mix with gas or oil.

Water vapor also slows pre-detonation, like the fuel is a higher octane, so you'd also have to tune your car for it.

If you can figure out a good way to do that, then I guess you may see some higher mpg's if you dial it in just right.

The part where I would NEVER advise anyone to consciously put water into the engine is because of blowback gasses. As the cylinder fires in normal operation of the car, a small amount the expanding gas blows past the piston rings into the engine, causing pressure to build up. A PCV valve is used as a one way valve to relieve the pressure of the gasses, and vent them into the intake. Water vapor in the oil causes it to gunk up. Either having that valve stick open, or gunking up other parts of the engine. The worst thing I'd think you can do is have a turbo setup where the oil line cooling the turbo could get gunked up.

So higher mpg at the cost of engine parts? Not worth it. Imagine all the energy (probably electricity from burning oil) it takes to machine the parts the water would destroy? That's like the opposite of what I want.

If water in the gas really worked, then if I used 10oz of fuel in my chainsaw on a dry day, lets say it would idle for an hour. And on a foggy humid day, it would idle longer, no? Would you feel that's an accurate test?

[jamesqf]

Originally Posted by Christ

When you get water in the tank, you get a very uneven distribution of water and fuel through each injector, and that causes stumbling and other problems, if you can even get it started.

The problem is that the (non-emulsified) water, being denser than gas, collects on the bottom of the tank, and so if there's a bunch it will all go into the pickup tube & down the fuel lines, meaning you're trying to run the engine on straight water until it all runs through. That's why light airplanes typically have fuel drains in the tanks, so you can draw off a bit from the bottom as part of your preflight check, and see if there's any water accumulated.

[chuckm]

There is another issue to watch out for - steam is pretty corrosive. Since there is a chunk of steam normally present in the exhaust, I don't know if the higher fraction will cause much of an issue to your exhaust system.

In the engine, if water undergoes a phase change on the surface of the piston or piston wall, you might see pitting over time (microscopic thermal differential stress fractures resulting from the lower surface temperature where the water takes up the heat). In normal operation, this isn't an issue because the water is a product of combustion; it isn't present during combustion.