Orv's Engine
In late 2005 Orval Hill contacted me with some pictures of his creation
- he built a working experimental steam engine from an old ride on
mower engine using a pressure cooker for a boiler. I was intrigued,
projects
like this have turned up before, but Orv's is different in that it is
so clever, simple, and straight forward that just about anyone could
build one. The remainder of this article is Orval's words and pictures
- read on, hopefully you'll be spurred onto building one! The article
and pictures are © Copyright Orval Hill 2005 All Rights Reserved,
used with permission.
ORV’S STEAM ENGINE
My idea
for this project was two fold:
- Convert an existing engine; and
- To produce steam the modern way, like useing an induction
heater or a magnatron as in a (microwave oven).
This would be a very cheap, easy and environemtally friendly way. The
heaters being powered by an inverter and the inverter being powered by
a simple battery. The engine in this experiment was taken from a ride
on mower, converted then replaced in the mower proving it could do
useful work.
My idea is to convert any 4 cycle internal combustion engine to an
external combustion engine using water for fuel. This can be done by
changing the camshaft and crankshaft gears to a 1 to 1 ratio instead of
the 2 to 1 ration as now used and by modifying the exhaust valve.
Steam can be generated in a boiler by using an AC induction
heater or a magnetron as found in microwave ovens. Power for the heater
comes from an inverter in turn powered from a 12 VDC battery.
Using a 2 cylinder engine whose pistons are 180 degrees out of phase
with each other, in other words when one piston is at Top Dead Centre
(TDC) the other one will be at its bottom most position Bottom Dead
Centre (BDC).
Starting at TDC when the crankshaft starts to rotate and is 5 degrees
past TDC the intake valve starts to open, allowing steam under
pressure, to force the piston downward. At 170 degrees the intake valve
closes shutting off the steam. At 175 degrees the exhaust valve starts
to open and stays open till 355 degrees, thus expelling the spent steam
and the cycle starts over again.
For use over a long period of time, or continued use, the exhaust could
be expelled into a condensor which would change the hot steam from a
gas into a liquid. The liquid could be collected into a tank and
returned to the main fuel tank to be used over and over again.
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During my experimenting with
trying to convert a 4-cycle internal
combustion engine to a 2-cycle external combustion engine, I made some
mistakes and what I did to remedy them.
The first mistake was that I selected the wrong engine to experiment
with, that is I selected a 2 cylinder engine that had both pistons at
TOP DEAD CENTER at the same time instead of 180 out of phase, I wanted
an engine that had one piston at the top of its stroke, when the other
one was at the bottom of its stroke, this then would have given me 2
power strokes for every revolution of the crankshaft.
The second mistake was that I selected the wrong pressure cooker for
the job I wanted it to do. I selected an aluminum vessel, which was not
a magnetic material that I needed in order to use an induction heater.
I solved this problem by cutting out the bottom of the vessel and
installing a steel bottom in the pressure cooker.
I then had a problem with leaking; I solved this problem by using a
high temperature gasket-forming compound.
I used compressed air to do the experimenting with and to get the
timing correct.
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Orv's completed engine piped up to its
pressure cooker boiler.
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Orv's Pressure Cooker Boiler showing the
piping and pressure gauge.
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The piping within the pressure cooker to
gather dry steam and to some extent super heat it.
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I then had the timing gears, the
crankshaft and the camshaft gears
machined to where I could weld 2 bicycle sprockets, both the same size,
to the machined down gears in order to get my 2 cycle timing that I
desired.
When I first tried to run the engine, with compressed air, it would
only make ½ a revolution; this was because the compressed air in
the
cylinder would not allow the piston to return to the top of its stroke.
I solved this problem by changing the exhaust valve cam, I welded stock on
the leading edge of the exhaust valve cam, and then had it machined so that
it would open just after the intake valve closed and then stayed open
till the piston reached it’s top most position. The engine then ran
great.
To complete my experiment, I would then plug the induction heater into
a 120 volt ac source and heat the water to a boiling point and get the
pressure up to around 70 PSI before It would start leaking around the
gaskets and therefore the pressure would not go any higher, but the
engine ran fine at this pressure. I would then plug the heater into my
12 volt DC to 120 volt AC inverter, which ran off a 12volt battery
there fore completing my experiment.
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CAM TIMING
BLOCK DIAGRAM
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- Engine
- Battery
- Boiler
- 12 Volt DC to AC Inverter (mains voltage)
- AC (mains voltage) Induction Heater
- Throttle Valve
- Intake
- Exhaust
- Starter Motor
- Generator
- Fuel Tank
- Condensor
- Pump
- AC (mains voltage)
- 12 Volts DC
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SOME RECOMMENDATIONS
I would suggest using an older 2 cylinder motorcycle engine that have
the pistons 180 degrees out of phase, (see NO-1 above) this way you
would have 2 power strokes every revolution of the crankshaft, thus
doubling the horsepower.
Another idea would be to use a 4 cylinder engine, an automobile type,
as this would insure of having 2 pistons 180 degrees out of phase.
Remove 2 of the pistons and use say number 1 and 3. If the engine has a
timing belt instead of gears, you might buy a crankshaft gear and
install it on the camshaft, thus giving you the 1 to 1 ratio desired.
You can contact Orval at orvalhill AT peoplepc.com
Editors note: This project uses
heating powered by mains AC voltages (ranges from 110 VAC to 270 VAC
depending on where you live) and is suggested to use a magnetron
instead of an induction heater. It also uses a considerable boiler
space and is capable of producing hot steam. I recommend that you seek
the guidance and help of an appropriately qualified Electrical Engineer
and possibly a Mechanical Engineer before undertaking a similar
project. While it is certainly not beyond the home workshop, it does
utilise principals which if used carelessly or without knowledge could
lead to injury or possibly even death.
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