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 :)

Paul Lamar

Not to deprive you of the millions you would make but wouldn't a better
solution to the low power, low BSFC be to put the rotary engine in an
airplane where the only low power application is during taxi ?

John

ROFL PL