Paul, the reason I picked up on your RevMaster boo-boo is that I too
have been scratching my head for some time on a similar schemes.

Don't know if anyone noticed, but at Airventure 2008 Mistral had an
integrated Starter-Alternator tucked away in the corner. They were not
really showing it, but did honestly answer questions about it.

In the past, Starter-Alternators have been a royal pain in the ###.  But
with todays electronics, particulary the advances in
 Power FET's, it may
be an acheivable design.

As to the Starter-Alternator, I think the key is design the flywheel
permanent magnet alternator such that it will "just" generate the
maximum battery charging voltage at maximum engine RPM.

This is need to keep back EMF below battery voltage when in motor mode
at cranking RPM's.It allows a simplified starter chopper circuit,
when one considers the parasitic "Bode Diodes" of the switching
FET's,
while also preventing a disaster if a regulator fails.

Key elements would be magnet strength, magnet path and air gaps, and
number of turns on windings.

To regulate voltage in Alternator mode, the rectified output would have
to go thru a boost regulator circuit. Today these are quite simple,
consisting of an Inductor, FET, Diode and controll IC.

The Starter circuit is basically a Motor Controller, consisting of 6
FET's and a control IC.

As
 to injection, I've been thinking about some sort of Stratified-Charge
Quasi-Diesel.
I.E., starts with spark plugs, but runs as a straight Diesel once it
gets going. There seem to be several design efforts going this way, but
very quietly !

I think the key is to use a Turbo to boost overall compression ratio
into the normal Diesel range, and maintaining the heat generated by the
turbo's 2:1 to 4:1 pressure ratio. Hence no Intercooler and no Throttle.

I.E., recover some exhaust power, muffel the exhaust, eliminate intake
pumping loss, and perhaps even generate a little torque during the
intake cycle.

Assuming lower exhaust temperatures of a diesel, use of best apex seals
and modern coatings, how high can the inlet temperature go ?  The great
unknown !

Still trying to fully understand effects of altitude vs pressure ratio
vs turbo maps.  Would be nice if it could be done without a waste
 gate,
by limiting Injection at maximum manifold pressure.

As to Injection, have been thinking about a pair of Bosch Single
Cylinder Injection Pumps, mounted 180 degrees apart on a single cam lobe
off the front crankshaft.

Why two seperate pumps vs 2 cylinder unit ?Plumb one to the starbord
tank, and the other to the port tank.  A few drops of water will stall a
diesel.

My thought is that one rotor would keep running (at a little less than
half power) while it purges water out of the other system. Better than
having the engine totally quit !

Finally Ignition.  If the injection pump is doing the timing, Ignition
could contineously occur over the begining portion of the injection
cycle.  And if the engine runs as a Diesel at flight RPM's, there would
be no need for dual ignition.

The Ignition circuit may be as simple a as field of magnets exciting a
pair of high voltage coils mounted
 180 degrees apart.  (High voltage =
20 to 30 KV !)  The mass of these magnets could replace mass of the
balance weight.  The pitch of magnet's north south poles should be much
finer than that of the Starter-Alternator, to generate multiple
alternating cycles during the iginiton period.

I may post some sketches in a few days.

JCP

The GM Chevy Malibu "hybrid" (I think) has a starter alternator.
It is not built into the flywheel. It looks like a heavy duty
alternator and is belt drive to the crank.
The starter part is so strong it moves the car in slow speed traffic.

Paul Lamar


Typo correction:  "Body Diodes", not Bode Diodes" in the FET's.

Had seen write up on an automotive Starter-Alternator, did not now it
has been deployed.
May make a very good starting point for some reverse engineering.
Wonder if it works off 12 VDC, or the much higher hybrid battery voltage ?

Thinking in terms of larger diameter with more poles, to compensate for
3-4:1 pulley ratio between engine and Starter-Alternator (assuming
direct drive built into flywheel approach).
Less RPM, more Torque !

Problem is finding a source of larger stator lamination's.
Not something one can easily buy only a few pounds of.
See articles using "smart" washing machine direct drive motor for
windmill alternators.
But they appear to be way too large.
(I don't think these washing machines were sold in the USA.)

"Thinking Outside the Box"
JCP