Six Stroke Engine

[Deadwood]

I am probably behind the times as usual, and I am not sure if this has been discussed on here or not, but this new six stroke engine was dicussed pretty heavily at the Railroad Engine House where I work.

Surprisingly enough, it was brought to my attention via a snowmobile website that did not give this engine much discussion. I'm kind of impressed however and as far as railroading, it has some merits.

I'll let you take the link and read the article fo yourself. I think this is a pretty interesting theory and protype engine and it just might have some serious ramifications in the logging industry.

Six Stroke Engine

[IL Bull]

That sounds interesting.  I wonder how much energy he is saving off the exhaust side. ???  Must be plenty if the engine runs that cool. :P

[jon12345]

That is pretty interesting and complex, I wish i could see a diagram but I think it'll be a while before he shows his secrets with the public.


IL Bull
-According to the article, he estimates a 40% gain in fuel efficiency and also the ability to burn lower grade gasoline.

[Ianab]

Thats an interesting idea.
Sorta like the local gas fired power plant, they use the waste heat from the gas turbines to fire a boiler/steam generator and recover a lot of the otherwise wasted energy. They get 20% more power from the same amount of gas.

I can visualise what he has done from the description, and he's not breaking any laws of physics, it's just a very clever idea. I'm guessing it's going to need many millions spent on it before you can buy a production one for your truck. I'm also wondering how he gets effecient combustion with the engine running so cool, but I guess thats what you build prototypes for   :P

Just wish I'd thought of the idea 1st  :D

Ian

[Minnesota_boy]

It won't work here.  Half the year the water tank will be frozen solid. 

[Quartlow]

It won't work here.  Half the year the water tank will be frozen solid. 

you have to get Costa Rican water, it doesn't freeze  :D

[slowzuki]

I didn't read the article that well but is he essentially burning one shot gas, one steam expansion, then exhaust cycle?

[Deadwood]

Since I work in the railroad industry, I see the greatest benefit there. Locomotives already haul vasts amount of water and their cooling systems are less than ideal. I am certain that if you could take away the inadequate cooling system, you could save some serious maintenance costs:

Cracked heads
Cracked Liners
Lower Liner Seals
Diluted Base Oil
Overheating

Locomotives are also designed around using straight water...no anti-freeze or presurized systems so they have that going for them right from the start. Their engines are also bullet proof. Two nights ago a locomotive came in with a piston sitting on the catwalk. In 48 hours it was hauling freight. The engines are just built for rebuilding and durability.

The interesting thing is that the four stroke motor never faired well with the locomotive. Fuel economy was only 3% better over the standard 2 stroke and the maintenance was quadroupled.

In any event, I was intrigued by the 6 stroke design and prototype and thought I would share it. It might not have got meuch attention on the snowmobile forum, but at work it was quite the discussion.

[Deadwood]

Slowzuki:

The typical 4 stroke engine goes:

Intake
Compression
Power
Exhaust

His engine (I believe) goes like this:

Intake
Compression
Power
Compression
Steam Power
Exhaust

Basically he is injecting water right after the pistons go down on the power stroke to convert the super hot cylinder temp into steam. That drives the piston down again with even more force. He eliminates the need for a cooling sytem because the water absorbs the heat and is turned into steam.

In essence he is getting 2 power strokes out of the same amount of fuel which is why his engine is so effecient. The beautiful part is, this steam powered stroke is free AND has more force than the fuel explosion power stroke. Additionally his engine does not need a water pump which also robs power from the engine.

I probably made that even more confusing for you, but it's kind of complex. The fact that he made a prototype is shy of amazing.

[Murf]

The linked article says he has a patent on the engine, in which case the information, including at least basic drawings, certainly is public and not secret at all.

The US Patent Office has a great website, including a search engine to look up patents.

[beenthere]

deadwood
Your explanation makes a lot of sense, as well as does the invention.
Will be interesting how things develop from here.

[slowzuki]

I'm a skeptic always  :D but I'd be interested to see how much power it actually makes because that second compression stroke would eat a bunch of power.  I'd also like to see what happens when the engine is cold and some water condenses on the expansion stroke...

It is an interesting approach, the best place to try and get more energy out of a motor is at the highest temperature place.  There may be a lot of energy coming out the exhaust and the cooling system but its all low temp compared to the combustion inside.

[Deadwood]

Slowzuki, I do not believe his engine robs power by using the second compression stroke because it is not really compressing anything. I believe, which means I could very well be wrong, but I think the exhaust valves are open so that the piston on the upstroke is not compressing that much air.

I am guessing that the engine still has enough heat to make steam though. I think at top dead center of the 5th stroke, he injects atomized water (think diesel injector now) into the combustion chamber. As the water is instantly turned to steam, it expands at 1600 times, driving down the piston for a second free power stroke. As the piston lowers itself, more steam is made and expands because more of the hot cylinder wall is exposed.

Then, at bottom dead center of the 6th steam exhaust stroke, the exhaust valve opens and the steam is forced out. This would not rob much power either because the valve is wide open and thus venting as much of the steam out as possable...that is, no compression to speak of.

I think the key to this whole design is the double cam shaft. Because Crowley has spent his entire life making custom cam shafts, he is about the only one who could design this engine. I think the sequnce of the exhaust, and steam injector valves is the true key to the entire engine concept. What I cannot figure out is how the wet spark plug does not foul itself out?

[Deadwood]

My post above was too long to discuss an important part of this engine...the steam injector. I think what happens is the fine mist sprayed on the cylinder walls is converted to steam quickly.

The only way I can explain this is how a diesel injector was explained to me. If you took a lit candle and a small spray bottle set to stream, when you sprayed the candle the stream of liquid would actually put the candle out.

Now if you put the spray bottle on a fine mist and spray it at the candle, you get a fireball. That is because the fuel is atomized (finer molecules mixed with losts of oxigen).

The same holds true with his steam injector. Because the injector sprays such a fine mist of water, it creates steam far better and over a larger surface. This makes "hotter" steam and because it is over a bigger surface, collects more heat from the cylinder walls.

What I am trying to say is, with this fine spray, the walls of the cylinder would only have to be above 212 degrees to make steam. If the exhaust valves were wide open on the fifth stroke, there would still be enough heat from the fuel explosion power stroke to create steam. I think that is why he said his engine would run better if the "cooling fins of his engine were removed." That makes sense because with less surface area on the cylinder walls, the explosion would make the walls hotter until the steam was generated a spilt second later.

My only question is, at what point does the continuous heat/ cool cycling take effect on the metalorgy of the engine? A typical engine enjoys a CONSTANT temp. This engine adds and subtracts heat at such a rate, I would think metal fatique would come into play.

[Ianab]

What I cannot figure out is how the wet spark plug does not foul itself out?

I'm guessing he only injects a small amount of water, atomised like you said, that instantly flashes to steam, and not enough to saturate the hot air and leave liquid water laying around. The cylinder / spark plug are still warm, so water isn't going to condense on them.
I see he mentioned using distilled or rain water, I imagine having lime scale build up in the engine would be a bad thing 

Ian

[Deadwood]

Ianab,

I don't see the issue of non-distilled water as a problem. Locomotives go through a lot of water due to bad seals, cracked heads, and the like. I mentioned earlier that their cooling systems do not use anti-freeze or is presurized. What it does have however is something we call "Treatment."

It's a dye product that keeps the interior of the engine from deteriating from scale, carbon and rust. We went a year without using this stuff and starting spring leaks everywhere. As cheap as our little railroad is, we went back to buying the stuff.

I think this might be the answer to the issue of distilled water. The cost is pretty low for this stuff and 1 gallon of treatment treats 500 gallons of water.

Now please, don't get the wrong idea here that I got all the answers for this engine. As I said we discussed this issue ALOT at the engine house. I'm facinated with the concept and it's not like we work on locomotives all that much!!

[SPIKER]

this is very interesting, (my firts love is hot rods: noticed the crower name right off. ;)



Intake
Compression
Power
Compression
Steam Power
Exhaust

I would think that the 6 stroke would be very benificial, first off the seniro above woud work BUT I think that a bit more explaining should be done so that



Intake (intake valve open, fresh air & fuel into cylinder piston goig down)

Compression (both valves closed piston moving up to TDC & spark or no spark for compression ignition )

Power (valves closed still piston going down)

Compression (EXHAUST valve open (bring back in the heat to help it heat the water spray and in multi cylinder applications draw heat from exhaust of other cylinders 7 scavange then faster too,)  for return UP cyl bore)

Steam Power (spray in distilled water so no formations occure piston moves down)

Exhaust ( piston UP and exhaust valve open )

this is pretty ideal situation, crower describes using a injector similar to a dirrect injection of diesel uses, there is a varriation that has been around a while which uses a small passageways and multiple very small orfices UNDER the exhaust valves sealing face.  (actually this under valve design is used to run gas into engines and the gas is vaporized inside the valve seat for better combustion.)

anyhow the 6 stroke design would make for a lot of good descussions

Mark M

[slowzuki]

The concept certainly is neat.  I'm fairly sure without my steam tables being handy that you need temps higher than 212 as the presure rises or it will revert back to condensed liquid.  But I'm also sure you can find high enough temps in there to do that.  The bigger problem to me is the lower the surface temps are, the worse the HC and CO emissions will be on the gas version of the motor.  NOx will be very low though at least.  They should move to a diesel version perhaps to avoid that issue.

Good to see innovation!

[beenthere]

Probably a good reason, but I'm wondering why not compress the hot exhaust gas (leave EXHAUST valve closed after fuel combustion) so as to not lose that heat which is converting the water to steam?

[Minnesota_boy]

Um, that hot exhaust is what caused the power stroke.  If you recompress it you have no power, not even enough to bring the piston back to TDC.  Better bet would be to wait until the exhaust valve was closed and then inject the water spray and capture the power with a turbine.

[SPIKER]

Probably a good reason, but I'm wondering why not compress the hot exhaust gas (leave EXHAUST valve closed after fuel combustion) so as to not lose that heat which is converting the water to steam?

the exhaust valve must open up when the piston starts comming back up, if it didn't then it would not be able to COME UP as the expanding gasses oer fills the cylinder hence the power stroke.   once the valve is open the piston moves up freely only pushing out the spend combustion gasses.   
markM

[beenthere]

Thanks, that does make good sense.