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

That is a very interesting figure, I think I will have to look at it
over the weekend to see if I can understand it...

What does "saked" mean?  Do you have to drink hot rice wine to work
with trochoid equations?

Hans

I guess maybe I was sakied when I tried to spell asked - I are an injuneer
not a spellyar
The housing form is generated by mathematically rotating a point at
eccentric offset radius
(otherwise called half the stroke by us heathens) while roating a point at
the radial distance
from the rotor center to the seal tip at one third the angular rate.
RE = RADIUS OF ECCENTRIC       RR=RADIUS OF ROTOR CENTER TO SEAL TIP
FOR ANGL = 0 T0 1080 DEGREES
X= (RE *SIN(ANGLE))+(RR*(SIN(ANGLE/3))
Y= (RE*COS(ANGLE))+(RR*(C0S(ANGLE/3))
I think that should do it if I have not mistyped.
Vance J

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