Thanks for the info / input.
One of the reasons for low NOx in the Wankel is the dilution of the
intake charge.
Just another loss of efficiency factor I would like to minimize.
Love the air curtain idea Paul ! Had not thought of that one !
Now, the natural stratified charge you mention is hard to control and
probably only works at higher rpm.
I believe ultimate efficiency at part throttle / lower rpms is only
going to happen with direct injection.
The low BSFC figures mentioned for the LeMans engine etc are great but I
don't believe they are going to hold up against the recip under light
load / part throttle conditions without direct injection. I see this as
the main way to get around the achille's heel of the Wankel, it's
relatively poor surface to volume ratio. I don't see any way around the
inherent shorter lever length problem ( " e " or eccentricity ) which is
about 1/2 of what most comparable recips have, right ? Does anyone have
an opinion how much this factor alone affects fuel economy / torque ?
In the Rolls Royce diesel Wankel (the 2-R6 produced 325 hp @ 4500 RPM
and weighed 929 pounds) the injector was placed a few degrees before the
minor axis. ( This is what Norbye states but his diagrams show the
injector just after the minor axis) In the Rolls Diesel Wankel, the
exhaust charge exited the exhaust port and entered one half of the
wankel compressor and helped drive it .... similar to Mr. Lamar's idea
of using exhaust energy to drive a turbine of some sort which in turn
helped drive the eccentric shaft again ! I have not been able to find
much on this Rolls Wankel. Norbye says in his book, " The technical
details of their experimental engines have been classified information
under the terms of British Government contracts" This is still true all
these years later ? All I know is development stopped in 1974 after
Rolls had a bout with bankruptcy ?
On your injector position (1 O clock high) ... holes in the rotor casing
should be avoided at this area to prevent leakage backwards during the
combustion cycle.
Interested in patents, especially as concerns the Wankel ?
see:
http://www.uiausa.org/Publications/FreeBook/PPart9.pdf
start reading at page 14. (ok this guy is a little biased against the
Wankel I think, as some of his statements are not correct, factually
speaking)
Wankel's 1958 USA patent for the wild DKM
patent number 2,988,065 (33 pages)
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=2988065
Wankel's 1957 USA patent for the KKM
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=2988008
I love Wikipedia
http://en.wikipedia.org/wiki/Wankel_engine
http://de.wikipedia.org/wiki/Wankelmotor
http://en.wikipedia.org/wiki/Wankel (section on aircraft engines !)
Perhaps the wildest thing I read .....
"Perhaps the most exotic use of the Wankel design is in the seat belt
<http://en.wikipedia.org/wiki/Seat_belt> pretensioner system of the
Volkswagen
<http://en.wikipedia.org/wiki/Volkswagen> New Beetle
<http://en.wikipedia.org/wiki/New_Beetle>. In this car, when
deceleration
<http://en.wikipedia.org/wiki/Deceleration> sensors
<http://en.wikipedia.org/wiki/Sensor> sense a potential crash, small
explosive cartridges are triggered electrically and the resulting
pressurized gas feeds into tiny Wankel engines which rotate to take up
the slack in the seat belt systems, anchoring the driver and passengers
firmly in the seat before any collision."
*** Looks like this might be covered under SAE *Document Number: *980557
SAE
http://www.sae.org/servlets/index has over 100 very interesting
papers on the Wankel but they are now priced at about $10 each. If I
could just find a less expensive way to get these .... Maybe I could
copy them at a local University ???
Here is a nice animation !
http://www.keveney.com/Wankel.html
All for now .... time for bed.
zzzzzzzz
Toski
Some of that wikipedia stuff is total nonsense.
http://en.wikipedia.org/wiki/Wankel_engine
"A further problem caused by the shape of the seals in Mazda engines is
that carbon particles can become trapped between the seal and the casing,
completely jamming the engine and requiring a partial stripdown to rectify.
Such engines should never be started and run unless the engine will reach
operating temperature; most such instances of jammed engines occur when
a car is started and moved a few yards, e.g. from a garage to a driveway.
In these situations it is better to manually push the car."
In over a million miles of driving six different Mazda Wankel powered
cars over the last 34 years I have never had this happen. Pure BS.
"Unlike a piston engine, where the cylinder is cooled by the incoming charge
after being heated by combustion, Wankel rotor housings are constantly heated
on one side and cooled at the other, leading to very high local temperatures
and unequal thermal expansion. This places high demands on the materials used."
More nonsense. Mazda heats the cool side of the engine with exhaust gas
passages in the center and rotor housings to equalize the temperature on
both side of the engine.
"In engines having more than two rotors, or two rotor race engines intended
for high-rpm use, a multi-piece eccentric shaft may be used, allowing additional
bearings between rotors."
Not necessary. Curtis Wright had a center main bearing with out split housing
on a two rotor engine.
"Some studies have indicated that at high speeds, the rate at which the volume
of the combustion chamber increases in the moments after ignition actually
out paces the expansion of the burning fuel. The result is that, at high speeds,
less useful energy is extracted from the same volume of fuel, as the exhaust
has to expend time and energy "catching up" to the rotor before it can accomplish
any work."
More nonsense. If that were the case the racers would not be running them at
11,000 RPM. Notice the "author" did not reference the "studies".
Paul Lamar ...No rotor no motor.
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