Vance W Jaqua wrote:

There was some mention of a 2 stroke Wankel, and that got the brain

cells

agitiated. I had often said tha a two stroke w\Wankel would be very
difficult, so I tried. Converting any positive displacement 4 stroke

engine

to an externally scavanged 2 stroke is very attractive. At the same
BMEP
and peak loads, you have the potential for twice the torque (and of

course

BHP) at the same rpm. Of course there is always a downside - ie the
integrated heat load is also doubled, and you need some sort of
external
pump..
To convert (or really build) a 2 stroke classicc trochoid Wankel.
you
need to use side porting that opens an exhaust port before rotor BDC
(max chamber volume), and shortly theafter open the intake port
to push the residual gases out and charge the volume, It is useful
to close the exhaust port to complete the charging (and perhaps some
super charging). The rather artsy geometric figure attached
represents
the rotor surface excursion in 10 degree incrementsof rotor
rotation.
The shaded areas represent the port areas as defined by the rotor
edge
(seal location modifies ths some what). Rotor rotation is clockwise
and the 2 sparkplugs would fire six times (power strokes) per
rotor revolution. Port areas seem rather restrictive and can only
be increased with more ovelap or duration.
An interesting exercise, and I would be intersted in the system
planned by the person that saked for the trochiod equations.
Vance J

Vance concept first. Hans second.

Paul Lamar

Gee! only a bit over 10 years too late. Probably a more detail search
would
find even
more earlier proposals. Should work just fine - I wonder if anyone
has run
one?
Vance J

I guess that I am the guy who asked for the trochoid equations.  I am
trying to interface with the machinist to get a proposal for a running
prototype to Marty, whose patent Paul just sent to the list.  Marty
told me he has never figured out how to machine a trochiod housing.
Right now Marty is focused on his steam engine that he is building from
scratch.  Others have told me that he had a running two stroke built on
a lawnmower wankel rotor and housing, but when I asked him about it he
said not really.  I take this to mean that it was a rotating model that
he spun up with external power or something.

I think I understand the graph you sent now, going to two-stroke limits
the port size.  Can you tell us what the port size would be say on a
two stroke based on a 13B rotor, I am curious to compare the relative
size of side ports on 2 vs. 4 stroke to try to understand what we are
up against.  I think the answer likely involves lots of boost.

Here is a thought I had:  Could you use two inline compressors
mechanically linked to the fast turning inner housing to generate
enough boost to allow compression ignition of diesel fuel in the rotary
piston section?  This would allow diesel fuel and eliminate the need
for spark.

Hans Conser

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.