Can A 2-Cycle Engine Be Made to Run Off Steam?

Not if you quit feeding it steam after 15% of piston travel.

The piston will stop and move back toward the top when the steam stops.

There's no energy left in the steam at that point.

Now, keep feeding it steam till the bottom of the stroke. Maybe.

How does the piston get back to TDC?

If low pressure steam, I see what you meant, but if high energy steam is used, this should continue to expand. I think the flywheel I have on it should be enough momentum to bring it around.

The only way it will continue to expand is if the engine is hotter than the steam.

You can't fool Mother Nature.

Flywheel, OK.

Why not siamese two engines together, bottom to bottom?

Please don't apologize for questioning anything I say.

The chuff results from the steam being at a higher pressure than atmospheric, not necessarily because it is still expanding inside the cylinder.

You may be right. Maybe this will be resolved.

at what pressure of the steam for 5% to 15%, ?,

at any reasonable pressure? - what pressure is being considered?

On a highschool "LASHME" (language,arts,science,history,mathe,english) day -- When I and the metal shop teacher had a dozen 7th graders BUILD and RUN 6 steam engines from scratch parts, ... the slide valve timing I set was over 110-deg swing of the yale-key-crank.

some ran a whopping 330 rpm!

CO2 model engines use more than 15% of the piston travel

This kid did it.....I think you need both valves though....

http://www.youtube.com/watch?v=mFEvZ125Eik

Here's another....

http://www.youtube.com/watch?v=POsJpHFhcbo

and another.....

http://www.youtube.com/watch?v=wqLW3gg74yQ

part 2....

http://www.youtube.com/watch?v=L1Xe07WyAt4

part 3....sheesh

http://www.youtube.com/watch?v=8ph4ZGlCD3g

How are you going to lubricate it?

What type of source are you going to use for steam?

I suppose you could make some type of gasoline burner to create the steam.

Probably some type of stainless steel steam coil, to handle >2000psig, and over 1000 F. I don't expect the steam to remain at this temperature during the down-stroke for very long, so I don't expect the aluminum to melt, but I might be wrong. I don't want to use oil a whole lot for lubrication, as this will pollute any condensate made to be returned through the exhaust. Maybe this is still going to be a "diesel" engine? If I use a fuel with a low flash point and induce it by using the original sleeve, then rely on the high temperature of the steam to make it ignite? No idea if the flammable limit could be reached this way, or if the steam would simply inhibit autoignition.

I think it will immediately seize and explode.....2000psig? 1000ºF?!

OK maybe that was an extreme example, so the P,T can be backed down quite a bit to keep from frying everything.

The old steam power house we are currently tearing down has a myriad of different size steam engines that range from 3 HP chemical/water pumps up to 350HP condenser pumps.

The entire system operated well on 300 PSI at 600F.

it wont make more energy than you put in it, the steam at best will just "turn the engine" no power generation

I have seen a number of single cylinder 4 stroke engines converted into simple steam engines being displayed at antique shows.

They work well and the only modifications are adding a second set of lobes to the camshaft opposite the original ones so that the intake valve opens on ever down stroke and the exhaust opens on every upstroke.

The only other mod as I understood it is re machining the piston to replace the two metal compression sealing rings with a larger single fiber or high temp synthetic rubber one to better seal the compression chamber from the crankcase.

Now relating to temperature most air cooled single cylinder engines can see cylinder and piston temps in excess of 400 F so if being ran on steam that would give you loads of pressure to work with without compromising the structural integrity of any of the parts.

Powerwise if one right and ran at a reasonable working pressures you should be able to get at least similar crankshaft power as what the engine originally had when working as a 4 stroke IC unit.

Basically its been done and works well if done right.

It depends upon the timing of the valves.

It will be a heavy rebuild. Why not just use a simple reciprocating steam engine instead? Secondhand off eBay an internet auction site, perhaps?

or that. Just happened to have the 2-cycle stuff lying around, and I was looking for a way to make it run almost silently.

in this simplistic drawing you can see how the case is basically open to the "inlet" side of the engine. everything that relies on lubrication will be washed away with steam, you'd have to modify the entire lubricating system of the cylinder walls. crank, rod bearings, etc.

Yes, the whole "project" appears somewhat hopeless from the point of view of adapting what I have on hand, but I will still probably mess around with the idea some more, and see if I learn anything new.

to be clear. I'm not attempting to discourage you from trying something unconventional, not at all. I just merely pointed out a couple of critical issues you face no matter how much support the idea has. it's an interesting concept, good luck

Both two-stroke (not "two cycle" - they only have one operating cycle!) and four-stroke internal-combustion engines have been successfully converted to steam operation. So have compressors and a miscellany of other piston machines.

Converting a crankcase-scavenged 2-stroke to steam does involve providing a steam inlet in the cylinder head, leaving the end-of-piston travel exhaust port as is, and of course some sort of valve gear to time the steam admission and cutoff.

Contrary to what has been claimed, such an engine, which is technically a uniflow or unaflow engine, can run continuously and produce a net power output even with only one cylinder, provided a good-size flywheel is provided. How much power it can produce, and at what efficiency, depends on steam inlet conditions, engine geometry, cutoff timing and whether the engine exhausts to atmosphere (sometimes called "back-pressure" operation) or into a condenser.

Lubrication in small piston steam engines is conventionally by "steam oil" carried along with the steam, and then separated out of the spent steam prior to entering the condenser (if any). More recently, small steam engines have been built and operated with dry lubrication, but the materials of a conventional IC engine presumably won't allow this. You would then have two lubrication systems: a bath or splash system in the crankcase, which would have a pool of oil in it like a conventional four-stroke engine, and a steam oil injector in the steam line. It might be possible to repurpose the rotary valve of a typical crankcase-scavenged IC engine to serve as the steam valve if you could manage with a fixed cutoff.

Thats a cool idea. You could modify existing two strokes for steam power this way. Interesting idea....

I have seen steam engines and locos for boys which use two stroke configuration

and a heavy flywheel .The construction was very simple cylinder was connected to

the crank ,and because of crank movement cylinder hinged on the rear had a radial

movement .this radial movement was used to connect the cylinder to pressure and exhaust ports.

Clever. Eliminates the wrist pin and would even allow double-acting operation of the cylinder.

It might be a fun project, but there is little chance that it will be viable unless you have access to a major amount of heat at no cost to you. Stoking a boiler for days at a time quickly cures most people of steam engines.....

Steam engines when made and setup well achieve about 11% efficiency if I remember correctly....not converted petrol engines which may not even achieve 1%....

A Stirling engine, if you have a cheap heat source, may be a better alternative if you really want to do something useful with your time and energy......

At this website:-

http://en.wikipedia.org/wiki/Stirling_engine

I noted this for example:-

The Stirling engine is noted for its high efficiency compared to steam engines,^[4] quiet operation, and the ease with which it can use almost any heat source. This compatibility with alternative and renewable energy sources has become increasingly significant as the price of conventional fuels rises, and also in light of concerns such as peak oil and climate change. This engine is currently exciting interest as the core component of micro combined heat and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.

I am certainly not advanced enough of a machinist to construct one of the newest (NASA) Stirling engine designs that uses the linear generator. But I could monkey around with a couple of 2-stroke engines. Maybe even use one of the smaller engines to act as the admission valve for the other one on a common flywheel/shaft.

I do plan on using solar heat with a fresnel lens on a telescope mount with the steam coils at the focal area. On lousy day, switch the coils out with one being heated with a wood fire - chimnea or the like... it is just a toy at this point.

I wish to thank all for their considerable input on this.

If I remember correctly, there was a patent by a gentleman named Fischer that used high temperature water injected through an injector, simular to a diesel injector, that then flashed into steam, and the amount injected was such that on the piston reaching it's maximum the flashed steam turned back into water and on the return to piston minumum was then valved off to return to the boiler. Kind of a 'two stroke design.

I am not sure if it belongs here but there is a motor than can run on petrol or diesel (design differences for the different fuels, its not the same engine), that adds an extra cycle where water is injected, which turns to steam, cools the motor and drives the piston down.

http://en.wikipedia.org/wiki/Six-stroke_engine

http://www.youtube.com/watch?v=UskFplqn1YM

I hope this is interesting enough for all concerned.....

I have to say, I do find this 6-stroke class of engines distinct and interesting. Not sure what to make of some of the earlier ones, as these were definitely intended for large stationary power applications, but the newer ones such as the Beare head engine look promising. Maybe I should focus on making a combined 2 piston engine where the pistons are on the same flywheel (same rotational speed, same frequency), but port the head of the smaller model plane engine to the intake of the larger weed whacker engine, and see what happens. Probably a train wreck, or a fuel (and air) starved mess. Surely that would be easier to do with a limited shop capability.

At some point I really want to get back to building a Sterling engine, and a steam engine.

I have to agree, if you have a cheap source of heat, a Stirling engine is the only answer....

As they are (fairly) easily constructed, simpler than a steam system and far less dangerous, as well as being far more efficient......

There is nothing inherently more efficient about a Stirling engine or a steam engine. In any heat engine, it's the source and the sink temperature that matter; everything else is secondary or of no effect whatever. Most commercial steam powerplants are far more efficient than any Stirling engine ever built, not because steam is better but because they operate at very high peak temperatures.

As for safety, to get decent power density out of a Stirling it has to be pressurized, and a pressure vessel is a pressure vessel. Actually, steam has an advantage there, because a once-through or flash boiler has a very small amount of live steam in it at any one time - it's exempt from the usual boiler certifications and inspections for that reason. But if a big Stirling ruptures while under pressure, it's bad news.

Don't get me wrong - I like Stirlings - but they are not inherently more efficient, or better in any other respect, than other heat engines. Whether they are the best choice in any given application depends on many factors, as does almost any other engineering decision.

And getting back to our topic, you can't convert an old lawnmower engine, or an old compressor, to Stirling-cycle operation. Not without adding a whole lot more hardware. And I'm not counting the boiler against the two-stroke conversion, because such conversions are usually used as auxiliaries in plants that already have low-pressure steam available.

Wikipedia (I have already posted the link here last week) is saying something quite different in a steam to Stirling comparison.

I know what I believe......you believe what you want.....

I found this:-

The Stirling engine is noted for its high efficiency compared to steam engines,^[4] quiet operation, and the ease with which it can use almost any heat source. This compatibility with alternative and renewable energy sources has become increasingly significant as the price of conventional fuels rises, and also in light of concerns such as peak oil and climate change. This engine is currently exciting interest as the core component of micro combined heat and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.

At this website:-

http://en.wikipedia.org/wiki/Stirling_engine

Maybe you need to contact Wiki and get some serious changes organized, written and published as they differ completely to your thoughts and ideas!

I hope this helps you further....

I realize that you're probably joking, but I'll say it anyway: Wikipedia is run by a committee of people ranging in acuity from extremely bright to borderline imbecilic. Some of their entries are valid, some aren't. This is one of the latter.

Pick up a text on thermodynamics and try to "believe" that. You'll have a better chance of being right.

I looked around on the web to see if I could drum up support for your take on this question of steam vs Stirling. I was sadly, unable to support your theories.

Here are some of the web links that I found:-

http://www.appropedia.org/Comparison_of_motors

http://www.cnccookbook.com/CCStirlingGenerator.htm

http://autonopedia.org/crafts-and-technology/engines/understanding-stirling-engines/

There are many other links praising the simplicity and efficiencies of the Stirling design.....especially modern versions with modern materials!

I did not find one that said that steam was cheaper and or more efficient, so I thought you could research them yourself and let us know where they are as I am sure you are not alone with your thoughts.....

Here is a book on "GreenSteam" that may interest many here:-

http://www.greensteamengine.com/

Let's try this, then. I will forget for the moment the laws of thermodynamics and stop questioning the oracular authority of Wikipedia - at least in this thread - so we can get back to the matter at hand.

You believe that Stirlings are inherently better than steam? Fine. Now tell the person who started this thread (remember him?) how to convert his two-stroke internal-combustion engine into a Stirling machine.

For bonus points, show him how to make that Stirling engine more efficient than a steam engine operating from the same heat source.

Ready? Begin...

You totally missed the point again.....

Just for you personally, I will say it again, most steam systems require continuous "stoking" and are not efficient. e.g. energy is being continually wasted (which is why continuous "stoking" is required!). A converted 2 stroke engine is MOST unlikely to ever achieve even the poor energy conversion of a properly designed steam engine...

According to many others, a Stirling engine can not only work at a far higher efficiency as even an "air" version should achieve at least double that of even the best steam engines, but is also far less "picky" about the quality of the heat or its source.

So it might appear that for the purposes of generating power, the home steam engine, though possible, is too complicated and far too inefficient.

Also we should not forget that due to the temperatures and pressures in a boilers for steam, the laws in most civilized countries require that the boilers be tested at regular intervals (at a heavy cost in time and money), and be licensed.

The laws where you are may be different.

Too many people have been injured or worse in the 17, 18 and early 19th Centuries before such certification was made law in the UK for example.Which is why private unlicensed boilers above a certain size, MUST BE CERTIFIED AS BEING SAFE. Even model steam locomotives and traction engines must be certified in the UK (and Germany!) for example.

Also, all pressure boilers must have proper safety devices, in full working order and the owner/user must have achieved a specific level of training before firing up....

If the aim is just for a bit of fun, to show that he can achieve rotation using air pressure as a steam substitute (not my impression but possible), then go ahead if it is legal (even high air pressures in the hands of an amateur can be dangerous) where he lives.

I and others, were just trying to demonstrate to the OP that he may want to try something simpler and safer......and to be aware of the dangers and requirements of using live steam.

May I ask what is wrong with that?

My guess is that the disagreement stems from differing assumptions about what is meant by 'steam engine'.

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I suspect that 'steam engine' elicits imagery of the machines that use to be the standby for trains to Andy Germany ....reciprocating steam engines.

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.....whereas for Piolenc, 'steam engine' easily encompasses modern steam turbines.

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The efficiency of the better examples Sterling engines is probably comparable to the better examples of reciprocating steam engines.

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Including modern steam turbines, results in the efficiency of sterling engines generally does not compare favorably with steam engines.

"I suspect that 'steam engine' elicits imagery of the machines that use to be the standby for trains to Andy Germany ....reciprocating steam engines.

......whereas for Piolenc, 'steam engine' easily encompasses modern steam turbines."

Basic thermodynamics does indeed encompass turbines, but I was not advocating the use of turbines. There is nothing inherently better about turbines, and in any case the original question was about a reciprocating engine. The turbine/recip question has to do primarily with operational constraints, not with efficiency per se.

Not that efficiency means much when converting such a simple machine. What converters of compressors and small IC engines are usually looking for is something that gives adequate power from whatever heat source they have, efficiency coming into it only when it comes to making sure that the engine will indeed be able to produce the necessary power.

'....There is nothing inherently better about turbines....'

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The sheer abundance of turbines in use today compared to the dearth of reciprocating steam engines for power generations might be something to consider.

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'....in any case the original question was about a reciprocating engine.....'

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Well, yes. But this particular line of discussion stems from Andy Germany's quite reasonable suggestion that a sterling engine would probably be better suited; and your dispute thereof, that began with a blanket denial of differences sufficient to create advantage with either system.

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I must have overlooked that at first glance. I was certainly trying to give you the benefit of the doubt. You have since worked hard to remove any uncertainty, so there really no longer any room to extend benefit.

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Andy is clearly correct. The attributes he list, simplicity, ease of construction, and efficiency are all real and advantageous. (I was wrong about the efficiency of steam turbines as compared to Sterling engines) When you further consider the reduced maintenance and the ability for function at lower delta T, Sterling engines have some significant advantages in the scenario discussed.

Has one seen the way the Martin 60, 1948 outboard motor used 2 strokes and two pistons and just 2 valves (one/each) ? [built by Martin Pressure Cooker Co.]

Putted around Tampa Bay in 1971 with one bought for 20 bucks!

What is the INHERENT advantage, -efficiency/ -to consumption, of the turbine over the current-possible machining of a steam recip?

Q: off topic tangently:::

How have any other systems of low pressure (used) steam turbines been working lately in refrigerants crossing the blades by way of temperature differentials from -10 or lower ambient temps to 55degree EARTH-COUPLED heat exchanger uses/exchanges that were in 1980, producing an inherently poor amount of electricity, then../now..?

http://www.yourownpower.com/Power/grc%20paper.pdf

Wow! More good answers...this is getting interesting. Suppose you take a heat source (probably a low grade heat of approximately 300 F.) On one hand you provide a Stirling engine that is the best design (putting aside the 2-stroke model plane engine, the weed whacker engine, etc) - the NASA design or one similar to that. On the other hand you provide the best steam engine available (non turbine). There is no steam re-heat taking place, just straight run. Now which one will do a better job of utilizing the 300 F temperature? My guess would be the Stirling, since you have the option of utilizing SCC as the working medium (super-critical carbon dioxide). The steam engine will have to face the issue of what happens at bottom temperature (bottom stroke) as to condensation of the steam? Don't get me wrong, there are conditions where steam is the best choice, others where Stirling is best choice, and many others where IC engine is the best choice.

GA

I am only surprised that I am the first!!!

Good common sense, which is missing in many posts here.....

Maybe I'll be able to answer one day soon, currently working on a sun tracker that transmits position information to a 8x12 heliostat that focuses on a sterling engine head with a 12" cylinder made form 1/4" wall pipe, crankshaft made from floating hubs from truck rear end with 3rd member cut out, regenerator stuffed with copper wool made from salvaged zip cord. Goal is to turn a 4500w belt drive generator. We'll have to see how fast the sterling runs. If need more heat I'll link a second heliostat. It's an experiment, who cares how efficient. I've got enough room for 3 more heliostats.

You are way ahead of me on this one. What type of heliostat are you using? I saw some on Youtube that use a fresnel lens, and it did run, but not all that great as far as stability of focus with wind buffeting the mount.

Currently under construction: Horizontal base made from a rear spindle removed from a rear axel from a front drive car. This is bolted to a plate welded to a 3" post in a 4' deep hole filled with concrete, appx. 6' to the top. The car rim is replaced by a large sprocket run by a 90v gear reduction motor running at 12vdc controlled by an 'arduino uno with pwm output driving an off the shelf controller ($14), the arduino analog in senses a 10 turn pot off the motor shaft to develop position info ( the sprocket ratio gives 180 deg w/ less than 10 turns. Same thing for the vertical. The mirror is 12" tiles mounted to a small plate on a 1/4" x 5" rod welded to angle iron frame made from bed frame. The 5" rod bends to allow each mirror to focus at the same point appx. 75' away. I'm currently working with 1 mirror until targeting software is finished. Then I'll mount the rest...don't want to cook any strays.

Brilliant!!!