OT: Interesting new idea, the six-stroke engine Options

[Dead Air]

I'm NO engineer, but
for atomized fuel to burn effeciently doesn't the combustion chamber need to be at a certain temperature? If the water cooled the chamber beyond that point, it seems the engine would be fighting with itself to maintain efficiency?
(IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[lapuwali]

QUOTE (Dead Air @ Mar 1 2006, 05:16 AM)

I'm NO engineer, but for atomized fuel to burn effeciently doesn't the combustion chamber need to be at a certain temperature? If the water cooled the chamber beyond that point, it seems the engine would be fighting with itself to maintain efficiency? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

Yes, quite right. The trick is to cool the engine enough that it won't self-destruct, but not so much that you end up with poor thermal efficiency, as the energy in the fuel will go to heating up the engine rather than pushing the piston. Essentially, the engine would spend all of its time "warming up".

It looks like this system could control cooling quite precisely, by varying the amount of water injected on each cycle. At some point, there's going to be an equilibrium between gaining power from the steam stroke, and losing it from overcooling. A dyno will quickly allow you to find this point (these points, more likely, as this will certainly vary as load changes), and you can program the water injection system accordingly.

[MattR]

QUOTE (guiltless @ Mar 1 2006, 02:05 AM)

Who really cares what the vapor does after it leaves the combustion chamber, unless you have a turbo after it. Just send everyhing on out the back.

If its a closed system you have to deal with the heat somehow. This appears to be an open system though and consumes gas. I had it wrong the first time. This makes a little more sense now. Instead of the water circulating through the system and worrying about cooling and bringing the vapor back to liquid, you just expell the vapor. Makes sense.

[MattR]

QUOTE (Porcharu @ Mar 1 2006, 01:53 AM)

Oh come on now! You don't know what water injection is?

Dont be a dick. I'm here to learn... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

[lapuwali]

Exhaust gas temps are typically in the range of 1200-1500dF, so it's safe to say that at the end of the exhaust stroke that's close to the ambient temp in the cylinder. That's 2-3x your number, so there you are.

[MattR]

And I dont see why it would have to run a high pressure in the water. Theres no need for atomization (since its turining into steam when it hits the chamber anyways), so you could flood the chamber with just a few PSI I would imagine.

[Rand]

There is an interesting article in the latest Car and Driver mag about a BMW engine. Is this a different animal???

I think it's cool when new designs come out. Time will tell.

Just pinging.... Anyone heard of the Bork(sp?) engine?

[pek771]

Did Crower patent this? I'd like to see the abstract. Also, I'd like to see a plot of the cycle on a T-S diagram.

Also, the staem portion likely produces little power. I'll bet that thing needs a 50 pound flywheel to carry the extra revolution while the vater vapor expands.

This is a good thermo problem for you aspiring engineers. Us old engineers don't have as much free time...gotta keep the Porsche fleet running first and foremost.

[lapuwali]

I don't know where to look up the expansion time for water into steam, or the "flash" time, but there's a fair amount of time to play with here. If we just pick a number out of the air, say, 3000rpm, that means each full crank revolution takes 20 milliseconds, so each stroke takes 10ms. Figure you'd actually use more than one stroke for the expansion time, as you'd likely inject the water while the piston was still rising on the exhaust stroke. Let's say 150% of one stroke, or 15ms. That's a pretty long time, really. Plenty of reactions are measured in picoseconds. Sammy, I'd love to see some actual numbers on this, since I have no idea what the actual times are.

We're not going to be talking a large volume of water here, either. Since water expands to 1600 times its volume as steam, a volume of water that's about 1% of the cylinder volume would generate considerable pressure as steam. That's 5cc for a 2.0 four, which would expand to 8000cc of steam, or 16bar of pressure in the cylinder with the piston at BDC. If the water were injected with the piston near TDC, you'd be looking at a number 8-10x that.

[alpha434]

Ok. So from my understanding. And correct me if any part of this is wrong (I'm as new to this as the rest of you are.)

1. Intake open, gas/air intake. Downstroke.
2 Upstroke Combustion.
3 Downstroke. Compression.
4. Exhaust partially open to prevent overpressurization in combustion chamber. Upstroke.
5. Water spray. Flash vaporizes. Expands in an envrionment that would be at a the highest pressure that the operating temperature will allow the water to flash at. Downstroke.
6.Exhaust full open. Everything comes out. Upstroke.

So a turbo wouldn't matter. The water would be vaporous and would just pass through like the air does.

The engine would benifit from the heat transfer from the metal to the water during stroke 5.

Water could possibly be recollected from the exhaust. For efficiency.

The car would benifit (powerwise) From having two downstrokes for the same fuel expense. And a direct port cooling system.

So less heat overall from the cycle. And the trick would to keep the cylinders within operating temp to prevent early wear. Except the comps that we have today would handle that.

And timing would have to be figured carefully, for the water cycle. Since that takes time. So a timing retard and less water injected at higher RPMs, right?

EXCEPT!!! That during the start phase, the engine wouldn't be hot enough to phase change the water. But the heat transfer is from exhaust to water, so this would be ok, as long as there is a combustion before water is injected.

So there will be small flaws that need perfected, but otherwise this is something that is far below our technological standards today, and those should be cleared up by what? 2007?

[pek771]

Yeah, but you have to examine a Mollier diagram of the expansion. The chamber pressure would be higher at the point of water injection. Crower says the engine uses equal amounts of water and fuel, and you could probably run 15:1 CR in the engine.

I can't find any patent application for this.

Pat

[alpha434]

QUOTE (pek771 @ Mar 3 2006, 08:59 PM)

Yeah, but you have to examine a Mollier diagram of the expansion. The chamber pressure would be higher at the point of water injection. Crower says the engine uses equal amounts of water and fuel, and you could probably run 15:1 CR in the engine. I can't find any patent application for this. Pat

Yeah. But that was just to make his one cylinder test subject run. Someone said that the water takes time to "flash." So retard and less water would be logical. Since that would give the water more time to expand.

And wouldn't the CR still be somewhat dependant on fuel type? Or are we treating the water as a "boost" variable?

[Porcharu]

QUOTE (MattR @ Mar 1 2006, 10:24 AM)

QUOTE (Porcharu @ Mar 1 2006, 01:53 AM) Oh come on now! You don't know what water injection is? Dont be a dick. I'm here to learn... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

I was not being a dick, or anything else. I'm just suprised that you didn't know about something that has been around longer than we have been alive, besides you seem to know a fair amount of stuff. (IMG:http://www.914world.com/bbs2/html/emoticons/mueba.gif)

[alpha434]

QUOTE (Porcharu @ Mar 3 2006, 11:18 PM)

QUOTE (MattR @ Mar 1 2006, 10:24 AM) QUOTE (Porcharu @ Mar 1 2006, 01:53 AM) Oh come on now! You don't know what water injection is? Dont be a dick. I'm here to learn... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) I was not being a dick, or anything else. I'm just suprised that you didn't know about something that has been around longer than we have been alive, besides you seem to know a fair amount of stuff. (IMG:http://www.914world.com/bbs2/html/emoticons/mueba.gif)

Yeah, Matt. You gotta learn all the cheap tricks that people forget about.

Run the breather hose to the exhaust!
(IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif)

[TimT]

Isnt there a 6 stroke engine out there already? in a prodution car?

it doesnt use water in its combustion cycle...