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 Madrid, Spain

It seems German and British engineers difered in several things
besides measuring 'metric' or 'imperial', or in the direction an
screw is to be turned to 'go inside'; when building aircraft engines,
UK liked smaller displacement engines, working at high rpm, and at
high MEP, and Germans chose high displacement, slowly turning
engines, almost never used at full open throttle, to minimize chances
of engine being overloaded or suffering a failure, and also giving a
longer life and time between TBOs, but the engines ever having shown
the best time before overhaul were the radial, air-cooled, single
sleeve-valve distribution built by Bristol during WWII, on the work
by Fedden and Ricardo, with a TBO of 3000 hours or even more. Thanks
for your attention, best regards. Salut

Jose Gros-Aymerich Madrid, Spain

   Hello again!: I reviewed the SAE paper about the OMC snowmobile
engine, and although it's described that it has both peripheral and
side intake ports, and a lateral view of the housing showing the PP
control system is included; I've been unable to find a full drawing
of this engine. Does anybody know a link or source for finding a
complete sketch of this OMC small, air cooled, Wankel RCE?

A US university build a micro-car around this engine, with a
continuous variation transmission, the two pulley and belts type,
and claimed a fuel economy of 25 mpg, that sounds too low for an
engine with a chamber displacement of around 300 cc, less than
36 HP, and installed in a car with a weight below 700 kg.
Thank you, have a nice year 2014. Regards. Salut
   Jose Gros-Aymerich
 Madrid, Spain

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