[Stoves] Bisschop Engine – rough & ready

[Jeff Davis]

Dear List,


This will be a multi-part e-mail regarding the Bisschop prime move.

Andrew wrote:
>I've allowed myself a little crosspost 

Me to.

On Tue, 05 Sep 2006 18:48:22 -0600, Tom Reed wrote:
>We are coming to the conclusion that producer gas has a very wide 
>flamability limit.  This would be due to the ~20% H2 in it (like 
>Synthane).  This would explain how a million non technical people could 
>operate converted cars during WWII.

~20% is great. Roy McAlister states ~10% min. when using hydrogen as a pilot 
fuel.


Andrew wrote:
>Jeff Davis has mentioned running an "atmospheric" Bisschop engine on
>producer gas,

The Bisschop engine is not a “atmospheric” prime mover it is a 
“non-compression”. At least that is my understanding.

Andrew wrote:
 >I've looked around and a chap I know, who builds model
>engines, says that these early gas engines will not run on lpg or
>natural gas because the mixture strength is so critical.

Or is it the missing lubrication hence tar.


Andrew wrote:
 >He posted
>that he had to resort to acetylene to get a similar engine to run. We
>know acetylene has both high energy and a very wide flammability
>range. 

Acetylene is sooty and soot is a lubrication.


Andrew wrote:
>This all points to producer gas being far more tolerant of
>varying air:fuel mixtures than natural gas.

Only if it has a good amount of H2?



Andrew wrote:
>BTW the Bisschop cycle seems very unlikely to be a good choice because
>of its poor thermodynamic performance. It appears it imbibes its
>fuel:air mix on the downward stroke, 

It's my understanding that it is on the up stroke thus intake stroke.


Andrew wrote:
>there simply is not
>enough temperature drop available to extract work from.

My understanding is that they where made up to two HP. One-third was the most 
popular. Do we really need more HP? One can do a lot with one-third HP.





This prime mover is a non-compression engine with poor gas consumption per 
horsepower. I see prime movers/engine as energy conversion devices so they 
take in fuel and output two species of energy. One form being power 
(macro-motion) and the other is heat (micro-motion). We talk a lot about fuel 
efficiency's and our prime movers just don't understand what our problem is. 
They do their job much better than we do ours. True, the Bisschop engine 
doesn't belong in a car. But, it's interesting how we want VERY efficient 
car/engines (etc.) so that we can drive all around whenever we feel like, 
sometimes just to unwind! In other words, we criticize our engines but our 
methods are ten times less efficient than our engines. So lets spend $50,000 
for a new fangled engine to somewhat make up for our inefficient methods.

Tool for every job and a job for every tool:
 Yes, I am all for a highly efficient engine (macro-motion) for our cars! BUT 
lets always look at our problems in a systems way. We pay good money for a 
furnace to heat our homes and most of the fuel is converted to heat and zero 
to macro-motion and we think that is great. It would be possible to heat your 
home with a Bisschop engine and get some macro-motion for generating electric 
or it could be used to power (macro-motion) an agglomerator to make fireballs 
and the micro-motion (heat) would be used to dry them. Of course this would 
all be on producer-gas.

Of all the engines to try to build, that will produce a usable amount of 
power, the Bisschop looks like the easiest. Even the simple Tesla turbine 
gets complicated, fast!


I plan on building a vertical Bisschop cycle engine --- some day:

-- No piston rings.

-- No tight piston to cylinder tolerance. Primitive machine shop.

-- No conventional governor (bag of gas & bag of air?).

-- 110 rpm

-- Sticky intake valves should not be the chillies heel.

-- Lots of heat for cogen (that's where I plan to increase my efficiency).

-- Maybe hard maple wood bearings (bio-bearings). Hey, it worked for Mercedes 
Benz. The bearings are at the top of the engine not at the bottom like the 
engine in your car. So, one could think of this engine as an inverted IC 
engine. Kind of like Tom's inverted downdraft gasifier.

-- The biggie, it needs NO crank case oil. It can not have oil in the 
cylinder. So how does it get cylinder oil? Answer: tar in the producer gas. 
Think of it as a two-cycle engine where the gasoline is mixed with oil. 
Although, I would not think that it would be prudent to feed it too much tar. 
I still feel that it would need a down draft gasifier. Someone built one and 
it would not run on propane, it needs producer-gas. Well, I hope that it 
would run on producer gas. It was reported to run on town-gas and 
illumination-gas. These gases are at least twice the Btu's as our 
producer-gas and have a good percentage of hydrogen.

-- No spark plugs or distributor junk.

-- No fuel injection junk.

-- It faced the efficient Otto-cycle engine and still was vary popular because 
of it's simplicity and reliability. It was always a small engine. The 1/3rd 
HP was the most popular. They may have made a two HP. So Peter has me out 
powered and he doesn't need the extra by-product (heat) like I do so this 
engine is not for everybody.

Hint: It would make a great engine to turn an agglomerator and the off heat 
for drying the fireballs.


Jeff


-- 
Jeff Davis
Somewhere 20 miles south of Lake Erie, USA
http://www.velocity.net/~jeff0124