http://www.nzherald.co.nz/motoring/news/article.cfm?c_id=9&objectid=11164644
Its got side-port intake, so its just a periport and exhaust port
massaging away from double the HP!
-Dan
"Yamanouchi had said the main problem with rotaries was the lack of
torque and need to rev hard, thus using a lot of fuel. His solution
was large displacement engines, far bigger than the 12A, 13B and 20Bs
the company has produced over the years. Suzuki confirmed that
passenger rotaries were still very much on the table."
Hmmm...
Their relationship is far more than arms length these days ( Mazda /
Ford ) but the Eco-Boost System used on a couple of their engines
have a flat torque curve ( which IMHO was pretty revolutionary and no
one saw it ) , my guess is this is achieved by modulating the
turbo-design and the wastegate. Why would not be this a natural
application for the Rotary and not have to upsize ?
Anthony AKA John Smith :)
They are wrong.
All they need is a European style auto shafting manual transmission
for better acceleration.
No need for a bigger engine.
The rotary engine suffers from high BSFC at low loads.
Low loads are the name of the game for automotive engines.
GM found back in 1978 that the temperature of the rotor face had a strong
effect on the low load BSFC. A 9.8% improvement in the BSFC
was possible with a hot rotor at low loads. Higher rotor temperatures
gave
lower fuel burn at low loads. However if the rotor was not
cooled at high loads the cast iron over heated.
GM got a patent in 1976 on a hot rotor face insulated from
the rest of the rotor. Here is a pdf on the 3,995,602 patent.
The SAE GM paper on the subject was 780419.
The obvious solution is to control the temperature of
the rotor as a function of the load on the engine.
The amount of oil cooling on the rotor is now controlled
by a ball and a spring that opens at a certain RPM.
RPM is not the problem. Engine load is the problem.
A way can be found to cut off the oil cooling to the
rotor at low loads regardless of the RPM. In other
words run the rotor face as hot as possible at all RPM's.
One mechanical way of doing that is insert a stationary tube
in the center of the e-shaft that moves back and
fourth controlled by a servo that senses engine
load and cuts off the cooling oil supply to the
rotor. A piece of cake for todays computer controlled
engines. In fact it need not be controlled by a computer
or electrical servo but by a simple air servo connected to the
intake manifold pressure.
Patent applied for :)
Here is another way.
Install a small cruise rotary engine bolted to the RX8 diff. A
mechanical hybrid so to speak.
Take advantage of the small size and light weight features of the
rotary engine.
Get an AIXRO Kart engine and mount it on the back of the RX8 differential.
Remove the stock rear cover. Use a second pinion gear and run the AIXRO
only at cruising speed with a one way clutch to disconnect it at lower
speeds.
Assume a 30 inch diameter tire and that gives a 94.248" circumference.
That is 7.85 feet in
circumference. At 95 feet per second or 65 MPH that is 12 revs per
second or
720 RPM. Multiplying by the 4.77:1 rear axle ratio yields 3434 AIXRO
engine RPM.
So you will need a 2.17 planetary gear reduction given 7452 RPM max HP
for the AXIRO engine.
That is also 114 revs per mile... per hour or 96 MPH at 11,000 AIXRO
max RPM.
My guess is the MPG running on the AIXRO alone will
be .73/.52 X 25 will be about 35 MPG. Converting the AIXRO to an oil
cooled rotor and EFI and the RX8 MPG could jump to 38.8 MPG.
Going the full turbo compound route on the AIXRO and getting
the BSFC down to .4 or below the RX8 MPG would jump to
.73/.4 X 25 or 46 MPG at a steady 65 MPH.
The cost of testing this is not beyond the means of an individual.
Paul Lamar
Interesting proposal. Some old research, I can't retrieve the
reference now,
pointed that the HC in exhaust are in reverse relationship to the Rotor's
surface temperature, the higher the Rotor surface temperature, the lower the
exhaust HC, and also the Yanmar Diesel research pointed that a TDR rotor
recess reduced the HC in exhaust respective to a MDR or LDR recess, this is
because of inherent features of the flame propagation in RCEs:
'Combustion and emission properties of Rotary Engines'; Automotive
Engineering, July 1972, pag. 26-29, (full issue download $14 at SAE.org)
based on SAE paper 720357 by K Yamamoto et al ($24, same site).
The effect of rotor recess shape on performance and emissions of RCEs
seems being dependent also on the number and placement of plugs,
Toyota showed best results were obtained with a glow plug in the
leading site, I don't know if such plugs are available in the market for
something different to model engines, but it would be interesting
having the opportunity of testing a glow plug in a full size RE.
As discussed previously, US patent 3848574 by Kawasaki proposed
changing the shape of plug hole to a wedge, with the end pointing to
the trailing edge of Rotor, to improve combustion, power and emissions,
I've hired from Kevin Landers in rotaryresurrection.com the implementation
of this change in a 13B engine, and I've done it myself also in a Sachs
KC-27 engine
from an Hercules W-2000 motorcycle, when I have some data bout the results,
I'll let you know.
How do you intend to change the Aixro charge cooled rotor into an oil-cooled
version? It seems a hard work, and I can't imagine the way for this.
Thanks for your attention. Best regards. Salut † Jose Gros-Aymerich
E-28033 Madrid, Spain
Add an oil pump and replace the needle bearing with plain bearings.
Paul Lamar
Ford had some patents around 1975 (Espacenet, search words Rotary
Engine, applicant: Ford)
about reed-valve controlled intake, and the SAE paper 790435 by Toyota,
besides describing
the air injection in exhaust ports, deals with the use of a glow-plug
and also a detailed mathematical
analysis on the effects of a reed-valve on part load performance, but
very early papers about the
Curtiss-Wright RCEs pointed that under part load, the Wankel had
better real life fuel mileage
than similar reciprocating engines.
Let's see this, but in an aviation use, as it seems it's the most
frequent among those who send
info (by the way, top quality one) to this site, part load functioning
is rare.
Thanks, salut
Jose Gros-Aymerich
E-28033 Madrid, Spain
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