Kevin & Kim wrote:

Right.  Bear with me while I think WAY out of the box... and come up
with a real hybrid. How about this: a compound rotary engine similar
to the old compound steam engines in ships 100 years ago.  Here's

how

it works (or not). One rotor runs like any, burning gasoline.
However, the exhaust gas is ported through the side and moves into a
second rotor as intake.  The second rotor then compresses the

exhaust

gasses further, creating more heat.  During compression, water mist

is

injected into the hot gas, which creates steam, which creates
additional pressure.  Then, the exhaust is expelled from the engine.
Something of a Wankel + Watt + Diesel multistage engine.... Anyone

try

this before?  Or, what's the detail that I'm forgetting that may nix
the whole thing? Kevin in Denver

Not that I know of. Hard to say if any. Sounds plausible. The key with

any

steam engine is the condenser.

Engines of this type are known as bottoming cycle engines and are

widely

used
in stationary gas turbine electric power plants. Waste heat from the

turbine

is used to
generate steam which drives a steam turbine. They are also highly

efficient

getting as much as 50% of the energy in a pound of fuel. The drawback

is

they are bulky and not suite to land mobile applications.

Paul Lamar

Sanderson wrote:

I have thought about a similar setup.  That is adding a rotor or two

to

the

back of the Mazda and running the exhaust through them.  I have seen
drawings of Wankle steam engines and that is where I probably got the

idea.

Extra housing and rotors could probably be made of lightweight

aluminum

because the exhaust gas would lose temperature rapidly as it expands

through

the engine.  This scheme would also eliminate the need for a muffler.

My thought is that the extra rotor(s) should be of considerably

greater

displacement than the main engine.  And/or they could be geared to

turn

faster.  One would also need a new eshaft.

Big downsides are greater weight and a longer engine.

The Tesla turbine has been around a long time but lacks any real

study.  I

have read that they can produce tremendous torque at low speed and I

have

also read that they produce no torque at low speed.  I have been

wanting

to

build a small one in my shop for a long time.  It would be most

interesting

to hook one up to the exhaust of an IC engine and see if I can get any
useful numbers out of it.  It is a project that sounds simple but I

know

from experience that numerous problems rear their ugly heads during

the

implementation of supposedly simple ideas.

Could the work of compression be eliminated if the exhaust and water

were

injected into the area of the spark plug hole?  This might allow the
expanding steam to produce work without having to first remove power

from

the other rotor.  It still sounds like a complicated version of

achieving

turbo-compounding.  Water ain't light, either!

Scott Gettings

mail2web - Check your email from the web at
http://mail2web.com/ .

I think that would be an improvement. Sort of like a compound steam

engine.

Paul Lamar

Instead of getting the steam working an otherwise useless rotor chamber why
not put an oversized turbo on the engine and inject your water between the
exhaust port and the turbine. If you have a turbine anyway your increase in
weight would be reduced. EGT's could be lowered and if you eliminated the
water injection at altitude you should be able to reduce the risk of turbo
overspeed. And of course we all know how simple it is to build a light,
cheap, easy, long lived turbo system.

John

 
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