Paul Lamar wrote:

Since I got this new pattern making capability I am thinking of
building a turbo compound gear box to hook to a ordinary
turbo charger. The way I figure it I will need a .32 inch
diameter pinion gear capable of 24 inch pounds of torque
at 120,000 RPM (50 HP) or a pitch line velocity of 10,000
feet per minute. I might need a planetary set up
to reduce the load on the small teeth.

That seems to be within the capabilities of gear makers.

The final drive could be a starter pinion on two or more
ring gears side by side. Pitch line velocity at 6000 RPM
with a 12 inch ring gear will be 19,000 feet per minute
which is pushing the envelope. Perhaps the starter pinion idea
won't work. I might have to go to a separate smaller diameter
gear on the nose of the E shaft.

The fluid coupling will be integrated with the gear box.

Check my math. Comments anyone?

0.32 inch seems pretty aggressive.

Why kill yourself to mesh with the engine rpm?  Drive the PSRU ring
gear and let the PSRU mix the engine and TC torque.

Russell Kent

That is what I originally planed but the ring gear pitch line velocity
appears
to be too high. 10,000 feet per minute appears to be the gear limit.

Paul Lamar

Russell Kent wrote:

Huh?  I assumed that there would be a step-down planetary between the

blow

down turbine and the ring gear mesh.  What am I not seeing?

Russell

6000 rpm on the 12 inch dia ring gear means the one inch starter pinion
is really
zinging along at about 72,000 RPM. That gives a mesh velocity of
19,000 feet per minute which is too high. No way around this except
to use a smaller ring gear. About 6.3 inches in diameter.

Paul Lamar

Paul - a wild thought - set up the redrive planetary such that engine power
is into the pinion
and power takeoff from the planet carrier. And then instead of locking the
planet ring,
you drive it additive from the compunding turbine. It runs slowly, as a
function of the power split
and it acts like a differential and you are not locked at a fixed speed
relationship. When
the engine first starts it might spin the turbine backwards slightly till
the exhaust power builds.

I still think you are overestimating the power recovery (turbine scale
effects to start with)
and that the best scheme is to drive a hompolar alternator, and off load all
accesory power
to the electrical system including water pump.
Vance J

 
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