[Gasification] OT - two stroke engine

[Bob Stuart]

On 2-Jun-07, at 11:53 AM, Peter Singfield wrote:

> At 10:51 AM 6/2/2007 -0600, you wrote:
>>
>> The working gas will have to be cooled by the cylinder walls as well
>> as by expansion in order to have a useful pressure difference between
>> the  compression and expansion strokes.
>>
>> Best,
>> Bob Stuart
>>
>
> "Work" cools Bob!!

Au contraire!  I'm in here because working now would make Bob  
sweat!   :-)

>
> The interesting thin is no work -- as in Idling -- no cooling --  
> bath temp
> goes up -- fan shuts down -- biomass combustion is greatly reduced.
>
> More "work" applied to crank -- bath temp goes down -- fan pops on  
> -- bath
> heated.

How is this communicated to the gas?  Does it not still see a moving  
piston changing its volume?  How could a pressurized gas expand  
against a piston and not do work?  It would either accelerate a crank  
and flywheel or make the piston into a projectile.  Neglecting  
friction, it would put just enough into the flywheel to re-compress  
itself to the same temperature.

>
> The channel restriction device (that is between expansion super  
> heater coil
> and cylinder varies/controls flow to limit RPM only.
>
> We do not want to ever condense vapor -- that would "slug" the engine.
>
> Granted -- maybe not very much work will be produced -- maybe only  
> 1/4 of
> an HP -- or so -- but work must be produced -- and work so produces  
> -- that
> energy comes from the heat of the vapors -- nothing else!!
>
> The cylinder and head must be insulated!!
>
> A preheating circuit must be included.
>
> Certainly -- no cooing --
>
> But == if you thinking steam engine -- you would be correct.
>
> Rather -- think sterling cycle.
>

Yes, I did immediately, and it has a "cold end."

> Theoretically this would work with just "air" to!!
>
> Anyway -- very easy to prototype and find out.
>
> What ever power that is generated will be produced with  
> exceptionally high
> efficiencies -- as it is a vapor only cycle -- no condensing!!
>
> True -- one might have to go to a 3 foot diameter piston to get  
> enough power!!
>
> After all -- the only work "force/energy" available for extraction  
> is the
> specific heat in that volume of gas.
>
> The prototype might not work because of insufficient energy to over  
> come
> friction of the mechanical parts involved!!
>
> OK -- to visualize this better then.
>
> Take a bicycle tire pump -- hook the end of that hose to a small  
> diameter
> copper coil emersed in boiling water --
>
> Pump down hard --
>
> I suggest the pump handle will "recoil" with more energy than you  
> applied
> to pump it into that coil.
>
> And easy experiment for any of you to try --

And then, how do I have a second compression stroke with less energy  
than the recoil, now that the average temperature of the air has  
increased?

>
> Boyle's laws anyone??

Yes.  He does not mention work.

>
> If you do not extract work from the recoil -- then you end up  
> heating your
> bicycle pump -- heat transfer -- rather than power generation.
>
> I figure a diesel engine can operate at 400 F --- so the "bath"  
> would be
> set at 400 F --
>
> Sure -- diesels in operation are cooled to 180 F by radiator and  
> thermostat
> -- as example.
>
> But you can easily measure 400 F and more off the exhaust manifold  
> -- right??
>
> Never mind what temp the piston and rings are running at -- during  
> their
> heat transferring to jacket cooling process.
>
> Try the pump trick Bob --
>
> If that does not produce "power" -- then we have to scrap physics!!
>
> And you can't extract power without lowering temps in that process!!
>
> This should twist a few brains ---
>
> And here -- another "twisting" - -why the 16 to one or higher  
> compression
> ratios??
>
> To get much faster heat transfer ratios!!
>
> What about the heat of compression??
>
> ah ha -- there lies the real question!!
>
> Well -- one might need to operate this device with below Atmospheric
> pressure at end of expansion stroke.
>
> The little light come on yet??

Several little red ones, actually.

>
> Theoretical start-up -- for steam example.
>
> The engine is heated to the same temperature as heat bath using  
> flowing
> steam at almost zero pressure.
>
> This could be best accomplished by opening a steam passage to a  
> copper tube
> positioned under the insulation of cylinder and head.
>
> Some details on engine changes --
>
> The intake port would be hermetically sealed -- the diesel injector  
> would
> remain in place -- the exhaust port would have exhaust valve removed.
>
> A small diameter pipe (regular steel car brake line should work  
> fine) would
> then be passed through the valve guide to just inside the cylinder  
> head
> through the now empty of valve exhaust port.
>
> A steel plate with a hole just the right size for brake line would  
> then be
> placed over valve orifice -- some packing (little fiberglass would  
> work
> fine) would be jammed around the brake line pipe at valve train end  
> of the
> valve guide.
>
> The head would be then so positioned that one could pour molten  
> aluminum
> down the exhaust port -- filling entirely that cavity and the valve  
> guide
> space between brake line and valve guide orifice.
>
> The cylinder should be preheated to at least 700 F before pouring.
>
> The preferred aluminum alloy would be melted down used engine pistons.
>
> After it has cooled down and turned solid -- take of the steel  
> plate the
> brake line passed through -- file grind flush.
>
> One could also do this same with the intake port. Two flash tube  
> boiler
> might work better than one!!
>
> Now -- back to the starting of this engine.
>
> The end of the flash tube boiler has a cap or valve protruding out  
> of the
> heat bath. This short extension (say two inches) will be well  
> insulated --
>
> It can either be capped -- or valved.
>
> After the engine is heated to operating temps -- and the flash  
> boiler bath
> -- then the original diesel injector is used to inject some water  
> to the
> top of piston -- with piston at top dead center -- which immediately
> flashes to steam -- and this steam travels out the flash tube  
> boiler -- out
> the other end.
>
> Once well purged -- the end of the tube is capped.
>
> The machine is now ready to operate.
>
> This engine will require external rotation to start.
>
> OK -- the piston is not put to bottom of stroke -- the diesel  
> injector pump
> -- which is now external to the engine -- and manually "pumped" is  
> stroked
> till the operating pressure required is reached. Which can be lower
> atmospheric!!
>
> When that point is reached -- one cranks over the engine briskly --  
> and
> hopes it will start - -and continue to run -- producing some power.
>
> One can tweak this engine on the fly -- same as tweaking a car  
> carburetor
> while the engine is running -- by voiding steam from the end of the  
> flash
> tube boiler -- or injecting more water --
>
> There should be no need for a governor -- maximum RPM will depend  
> totally
> on boiler surface area -- so flash tube coil can be built accordingly.
>
> More longer coils of smaller diameter having greater heat transfer  
> area
> than short fatter ones.
>
> No lost energy when engine tops out -- bath temps go up -- blower  
> turns off
> -- and stable operating RPM achieved.
>
> Load applied -- bath temps go down -- fan goes back on -- power  
> produced.
>
> It will be slow response -- but think running a DC generator to charge
> battery!!
>
> Let's twist again --
>
> Neat power plant that could run by simply putting the pot on any  
> stove!!
>
> When this engine tops out -- the heat would simply pass by and cook  
> one's
> rice and beans -- eh??
>
> I will use a small diesel engine for prototyping -- but as this  
> kind of
> engine would always be producing so little power -- one could use a  
> much
> lighter design in the end.
>
> and oh -- don't forget to block of the lube line to the head!! No  
> valves --
> no pushrods -- no nothing there that needs lube no more!
>
> Will it do "work"??
>
> Well -- why not??
>
> Try the bicycle pump experiment! Just use "air"
>
> Why use steam even??
>
> Higher specific heat.
>
> Pure CO2 is also very high specific heat -- if I remember right??
>
> There -- physics time folks!!
>
> Peter/Belize
>

OK, serve returned.


Best,
Bob Stuart